Enlist the FreeBSD-CURRENT users as testers of what is to become Gcc 3.1.0.

These bits are taken from the FSF anoncvs repo on 1-Feb-2002 08:20 PST.

40 files changed, 54530 insertions, 0 deletions

diff --git a/contrib/gcc/doc/bugreport.texi b/contrib/gcc/doc/bugreport.texi
new file mode 100644
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--- /dev/null
+++ b/contrib/gcc/doc/bugreport.texi
@@ -0,0 +1,394 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+@c 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Bugs
+@chapter Reporting Bugs
+@cindex bugs
+@cindex reporting bugs
+
+Your bug reports play an essential role in making GCC reliable.
+
+When you encounter a problem, the first thing to do is to see if it is
+already known.  @xref{Trouble}.  If it isn't known, then you should
+report the problem.
+
+Reporting a bug may help you by bringing a solution to your problem, or
+it may not.  (If it does not, look in the service directory; see
+@ref{Service}.)  In any case, the principal function of a bug report is
+to help the entire community by making the next version of GCC work
+better.  Bug reports are your contribution to the maintenance of GCC@.
+
+Since the maintainers are very overloaded, we cannot respond to every
+bug report.  However, if the bug has not been fixed, we are likely to
+send you a patch and ask you to tell us whether it works.
+
+In order for a bug report to serve its purpose, you must include the
+information that makes for fixing the bug.
+
+@menu
+* Criteria:  Bug Criteria.   Have you really found a bug?
+* Where: Bug Lists.	     Where to send your bug report.
+* Reporting: Bug Reporting.  How to report a bug effectively.
+* GNATS: gccbug.             You can use a bug reporting tool.
+* Known: Trouble.            Known problems.
+* Help: Service.             Where to ask for help.
+@end menu
+
+@node Bug Criteria,Bug Lists,,Bugs
+@section Have You Found a Bug?
+@cindex bug criteria
+
+If you are not sure whether you have found a bug, here are some guidelines:
+
+@itemize @bullet
+@cindex fatal signal
+@cindex core dump
+@item
+If the compiler gets a fatal signal, for any input whatever, that is a
+compiler bug.  Reliable compilers never crash.
+
+@cindex invalid assembly code
+@cindex assembly code, invalid
+@item
+If the compiler produces invalid assembly code, for any input whatever
+(except an @code{asm} statement), that is a compiler bug, unless the
+compiler reports errors (not just warnings) which would ordinarily
+prevent the assembler from being run.
+
+@cindex undefined behavior
+@cindex undefined function value
+@cindex increment operators
+@item
+If the compiler produces valid assembly code that does not correctly
+execute the input source code, that is a compiler bug.
+
+However, you must double-check to make sure, because you may have run
+into an incompatibility between GNU C and traditional C
+(@pxref{Incompatibilities}).  These incompatibilities might be considered
+bugs, but they are inescapable consequences of valuable features.
+
+Or you may have a program whose behavior is undefined, which happened
+by chance to give the desired results with another C or C++ compiler.
+
+For example, in many nonoptimizing compilers, you can write @samp{x;}
+at the end of a function instead of @samp{return x;}, with the same
+results.  But the value of the function is undefined if @code{return}
+is omitted; it is not a bug when GCC produces different results.
+
+Problems often result from expressions with two increment operators,
+as in @code{f (*p++, *p++)}.  Your previous compiler might have
+interpreted that expression the way you intended; GCC might
+interpret it another way.  Neither compiler is wrong.  The bug is
+in your code.
+
+After you have localized the error to a single source line, it should
+be easy to check for these things.  If your program is correct and
+well defined, you have found a compiler bug.
+
+@item
+If the compiler produces an error message for valid input, that is a
+compiler bug.
+
+@cindex invalid input
+@item
+If the compiler does not produce an error message for invalid input,
+that is a compiler bug.  However, you should note that your idea of
+``invalid input'' might be my idea of ``an extension'' or ``support
+for traditional practice''.
+
+@item
+If you are an experienced user of one of the languages GCC supports, your
+suggestions for improvement of GCC are welcome in any case.
+@end itemize
+
+@node Bug Lists,Bug Reporting,Bug Criteria,Bugs
+@section Where to Report Bugs
+@cindex bug report mailing lists
+@kindex gcc-bugs@@gcc.gnu.org or bug-gcc@@gnu.org
+Send bug reports for the GNU Compiler Collection to
+@email{gcc-bugs@@gcc.gnu.org}.  In accordance with the GNU-wide
+convention, in which bug reports for tool ``foo'' are sent
+to @samp{bug-foo@@gnu.org}, the address @email{bug-gcc@@gnu.org}
+may also be used; it will forward to the address given above.
+
+Please read @uref{http://gcc.gnu.org/bugs.html} for additional and/or
+more up-to-date bug reporting instructions before you post a bug report.
+
+@node Bug Reporting,gccbug,Bug Lists,Bugs
+@section How to Report Bugs
+@cindex compiler bugs, reporting
+
+The fundamental principle of reporting bugs usefully is this:
+@strong{report all the facts}.  If you are not sure whether to state a
+fact or leave it out, state it!
+
+Often people omit facts because they think they know what causes the
+problem and they conclude that some details don't matter.  Thus, you might
+assume that the name of the variable you use in an example does not matter.
+Well, probably it doesn't, but one cannot be sure.  Perhaps the bug is a
+stray memory reference which happens to fetch from the location where that
+name is stored in memory; perhaps, if the name were different, the contents
+of that location would fool the compiler into doing the right thing despite
+the bug.  Play it safe and give a specific, complete example.  That is the
+easiest thing for you to do, and the most helpful.
+
+Keep in mind that the purpose of a bug report is to enable someone to
+fix the bug if it is not known.  It isn't very important what happens if
+the bug is already known.  Therefore, always write your bug reports on
+the assumption that the bug is not known.
+
+Sometimes people give a few sketchy facts and ask, ``Does this ring a
+bell?''  This cannot help us fix a bug, so it is basically useless.  We
+respond by asking for enough details to enable us to investigate.
+You might as well expedite matters by sending them to begin with.
+
+Try to make your bug report self-contained.  If we have to ask you for
+more information, it is best if you include all the previous information
+in your response, as well as the information that was missing.
+
+Please report each bug in a separate message.  This makes it easier for
+us to track which bugs have been fixed and to forward your bugs reports
+to the appropriate maintainer.
+
+To enable someone to investigate the bug, you should include all these
+things:
+
+@itemize @bullet
+@item
+The version of GCC@.  You can get this by running it with the
+@option{-v} option.
+
+Without this, we won't know whether there is any point in looking for
+the bug in the current version of GCC@.
+
+@item
+A complete input file that will reproduce the bug.  If the bug is in the
+C preprocessor, send a source file and any header files that it
+requires.  If the bug is in the compiler proper (@file{cc1}), send the
+preprocessor output generated by adding @option{-save-temps} to the
+compilation command (@pxref{Debugging Options}).  When you do this, use
+the same @option{-I}, @option{-D} or @option{-U} options that you used in
+actual compilation.  Then send the @var{input}.i or @var{input}.ii files
+generated.
+
+A single statement is not enough of an example.  In order to compile it,
+it must be embedded in a complete file of compiler input; and the bug
+might depend on the details of how this is done.
+
+Without a real example one can compile, all anyone can do about your bug
+report is wish you luck.  It would be futile to try to guess how to
+provoke the bug.  For example, bugs in register allocation and reloading
+frequently depend on every little detail of the function they happen in.
+
+Even if the input file that fails comes from a GNU program, you should
+still send the complete test case.  Don't ask the GCC maintainers to
+do the extra work of obtaining the program in question---they are all
+overworked as it is.  Also, the problem may depend on what is in the
+header files on your system; it is unreliable for the GCC maintainers
+to try the problem with the header files available to them.  By sending
+CPP output, you can eliminate this source of uncertainty and save us
+a certain percentage of wild goose chases.
+
+@item
+The command arguments you gave GCC to compile that example
+and observe the bug.  For example, did you use @option{-O}?  To guarantee
+you won't omit something important, list all the options.
+
+If we were to try to guess the arguments, we would probably guess wrong
+and then we would not encounter the bug.
+
+@item
+The type of machine you are using, and the operating system name and
+version number.
+
+@item
+The operands you gave to the @code{configure} command when you installed
+the compiler.
+
+@item
+A complete list of any modifications you have made to the compiler
+source.  (We don't promise to investigate the bug unless it happens in
+an unmodified compiler.  But if you've made modifications and don't tell
+us, then you are sending us on a wild goose chase.)
+
+Be precise about these changes.  A description in English is not
+enough---send a context diff for them.
+
+Adding files of your own (such as a machine description for a machine we
+don't support) is a modification of the compiler source.
+
+@item
+Details of any other deviations from the standard procedure for installing
+GCC@.
+
+@item
+A description of what behavior you observe that you believe is
+incorrect.  For example, ``The compiler gets a fatal signal,'' or,
+``The assembler instruction at line 208 in the output is incorrect.''
+
+Of course, if the bug is that the compiler gets a fatal signal, then one
+can't miss it.  But if the bug is incorrect output, the maintainer might
+not notice unless it is glaringly wrong.  None of us has time to study
+all the assembler code from a 50-line C program just on the chance that
+one instruction might be wrong.  We need @emph{you} to do this part!
+
+Even if the problem you experience is a fatal signal, you should still
+say so explicitly.  Suppose something strange is going on, such as, your
+copy of the compiler is out of synch, or you have encountered a bug in
+the C library on your system.  (This has happened!)  Your copy might
+crash and the copy here would not.  If you @i{said} to expect a crash,
+then when the compiler here fails to crash, we would know that the bug
+was not happening.  If you don't say to expect a crash, then we would
+not know whether the bug was happening.  We would not be able to draw
+any conclusion from our observations.
+
+If the problem is a diagnostic when compiling GCC with some other
+compiler, say whether it is a warning or an error.
+
+Often the observed symptom is incorrect output when your program is run.
+Sad to say, this is not enough information unless the program is short
+and simple.  None of us has time to study a large program to figure out
+how it would work if compiled correctly, much less which line of it was
+compiled wrong.  So you will have to do that.  Tell us which source line
+it is, and what incorrect result happens when that line is executed.  A
+person who understands the program can find this as easily as finding a
+bug in the program itself.
+
+@item
+If you send examples of assembler code output from GCC,
+please use @option{-g} when you make them.  The debugging information
+includes source line numbers which are essential for correlating the
+output with the input.
+
+@item
+If you wish to mention something in the GCC source, refer to it by
+context, not by line number.
+
+The line numbers in the development sources don't match those in your
+sources.  Your line numbers would convey no useful information to the
+maintainers.
+
+@item
+Additional information from a debugger might enable someone to find a
+problem on a machine which he does not have available.  However, you
+need to think when you collect this information if you want it to have
+any chance of being useful.
+
+@cindex backtrace for bug reports
+For example, many people send just a backtrace, but that is never
+useful by itself.  A simple backtrace with arguments conveys little
+about GCC because the compiler is largely data-driven; the same
+functions are called over and over for different RTL insns, doing
+different things depending on the details of the insn.
+
+Most of the arguments listed in the backtrace are useless because they
+are pointers to RTL list structure.  The numeric values of the
+pointers, which the debugger prints in the backtrace, have no
+significance whatever; all that matters is the contents of the objects
+they point to (and most of the contents are other such pointers).
+
+In addition, most compiler passes consist of one or more loops that
+scan the RTL insn sequence.  The most vital piece of information about
+such a loop---which insn it has reached---is usually in a local variable,
+not in an argument.
+
+@findex debug_rtx
+What you need to provide in addition to a backtrace are the values of
+the local variables for several stack frames up.  When a local
+variable or an argument is an RTX, first print its value and then use
+the GDB command @code{pr} to print the RTL expression that it points
+to.  (If GDB doesn't run on your machine, use your debugger to call
+the function @code{debug_rtx} with the RTX as an argument.)  In
+general, whenever a variable is a pointer, its value is no use
+without the data it points to.
+@end itemize
+
+Here are some things that are not necessary:
+
+@itemize @bullet
+@item
+A description of the envelope of the bug.
+
+Often people who encounter a bug spend a lot of time investigating
+which changes to the input file will make the bug go away and which
+changes will not affect it.
+
+This is often time consuming and not very useful, because the way we
+will find the bug is by running a single example under the debugger with
+breakpoints, not by pure deduction from a series of examples.  You might
+as well save your time for something else.
+
+Of course, if you can find a simpler example to report @emph{instead} of
+the original one, that is a convenience.  Errors in the output will be
+easier to spot, running under the debugger will take less time, etc.
+Most GCC bugs involve just one function, so the most straightforward
+way to simplify an example is to delete all the function definitions
+except the one where the bug occurs.  Those earlier in the file may be
+replaced by external declarations if the crucial function depends on
+them.  (Exception: inline functions may affect compilation of functions
+defined later in the file.)
+
+However, simplification is not vital; if you don't want to do this,
+report the bug anyway and send the entire test case you used.
+
+@item
+In particular, some people insert conditionals @samp{#ifdef BUG} around
+a statement which, if removed, makes the bug not happen.  These are just
+clutter; we won't pay any attention to them anyway.  Besides, you should
+send us cpp output, and that can't have conditionals.
+
+@item
+A patch for the bug.
+
+A patch for the bug is useful if it is a good one.  But don't omit the
+necessary information, such as the test case, on the assumption that a
+patch is all we need.  We might see problems with your patch and decide
+to fix the problem another way, or we might not understand it at all.
+
+Sometimes with a program as complicated as GCC it is very hard to
+construct an example that will make the program follow a certain path
+through the code.  If you don't send the example, we won't be able to
+construct one, so we won't be able to verify that the bug is fixed.
+
+And if we can't understand what bug you are trying to fix, or why your
+patch should be an improvement, we won't install it.  A test case will
+help us to understand.
+
+See @uref{http://gcc.gnu.org/contribute.html}
+for guidelines on how to make it easy for us to
+understand and install your patches.
+
+@item
+A guess about what the bug is or what it depends on.
+
+Such guesses are usually wrong.  Even I can't guess right about such
+things without first using the debugger to find the facts.
+
+@item
+A core dump file.
+
+We have no way of examining a core dump for your type of machine
+unless we have an identical system---and if we do have one,
+we should be able to reproduce the crash ourselves.
+@end itemize
+
+@node gccbug,, Bug Reporting, Bugs
+@section The gccbug script
+@cindex gccbug script
+
+To simplify creation of bug reports, and to allow better tracking of
+reports, we use the GNATS bug tracking system.  Part of that system is
+the @code{gccbug} script.  This is a Unix shell script, so you need a
+shell to run it.  It is normally installed in the same directory where
+@code{gcc} is installed.
+
+The gccbug script is derived from send-pr, @pxref{using
+send-pr,,Creating new Problem Reports,send-pr,Reporting Problems}.  When
+invoked, it starts a text editor so you can fill out the various fields
+of the report.  When the you quit the editor, the report is automatically
+send to the bug reporting address.
+
+A number of fields in this bug report form are specific to GCC, and are
+explained at @uref{http://gcc.gnu.org/gnats.html}.
diff --git a/contrib/gcc/doc/c-tree.texi b/contrib/gcc/doc/c-tree.texi
new file mode 100644
index 0000000..cbf0196
--- /dev/null
+++ b/contrib/gcc/doc/c-tree.texi
@@ -0,0 +1,2307 @@
+@c Copyright (c) 1999, 2000, 2001 Free Software Foundation, Inc.
+@c Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@c ---------------------------------------------------------------------
+@c Trees
+@c ---------------------------------------------------------------------
+
+@node Trees
+@chapter Trees: The intermediate representation used by the C and C++ front ends
+@cindex Trees
+@cindex C/C++ Internal Representation
+
+This chapter documents the internal representation used by GCC to
+represent C and C++ source programs.  When presented with a C or C++
+source program, GCC parses the program, performs semantic analysis
+(including the generation of error messages), and then produces the
+internal representation described here.  This representation contains a
+complete representation for the entire translation unit provided as
+input to the front end.  This representation is then typically processed
+by a code-generator in order to produce machine code, but could also be
+used in the creation of source browsers, intelligent editors, automatic
+documentation generators, interpreters, and any other programs needing
+the ability to process C or C++ code.
+
+This chapter explains the internal representation.  In particular, it
+documents the internal representation for C and C++ source
+constructs, and the macros, functions, and variables that can be used to
+access these constructs.  The C++ representation which is largely a superset
+of the representation used in the C front end.  There is only one
+construct used in C that does not appear in the C++ front end and that
+is the GNU ``nested function'' extension.  Many of the macros documented
+here do not apply in C because the corresponding language constructs do
+not appear in C@.
+
+If you are developing a ``back end'', be it is a code-generator or some
+other tool, that uses this representation, you may occasionally find
+that you need to ask questions not easily answered by the functions and
+macros available here.  If that situation occurs, it is quite likely
+that GCC already supports the functionality you desire, but that the
+interface is simply not documented here.  In that case, you should ask
+the GCC maintainers (via mail to @email{gcc@@gcc.gnu.org}) about
+documenting the functionality you require.  Similarly, if you find
+yourself writing functions that do not deal directly with your back end,
+but instead might be useful to other people using the GCC front end, you
+should submit your patches for inclusion in GCC@.
+
+@menu
+* Deficiencies::        Topics net yet covered in this document.
+* Tree overview::       All about @code{tree}s.
+* Types::               Fundamental and aggregate types.
+* Scopes::              Namespaces and classes.
+* Functions::           Overloading, function bodies, and linkage.
+* Declarations::        Type declarations and variables.
+* Attributes::          Declaration and type attributes.
+* Expression trees::    From @code{typeid} to @code{throw}.
+@end menu
+
+@c ---------------------------------------------------------------------
+@c Deficiencies
+@c ---------------------------------------------------------------------
+
+@node Deficiencies
+@section Deficiencies
+
+There are many places in which this document is incomplet and incorrekt.
+It is, as of yet, only @emph{preliminary} documentation.
+
+@c ---------------------------------------------------------------------
+@c Overview
+@c ---------------------------------------------------------------------
+
+@node Tree overview
+@section Overview
+@cindex tree
+@findex TREE_CODE
+
+The central data structure used by the internal representation is the
+@code{tree}.  These nodes, while all of the C type @code{tree}, are of
+many varieties.  A @code{tree} is a pointer type, but the object to
+which it points may be of a variety of types.  From this point forward,
+we will refer to trees in ordinary type, rather than in @code{this
+font}, except when talking about the actual C type @code{tree}.
+
+You can tell what kind of node a particular tree is by using the
+@code{TREE_CODE} macro.  Many, many macros take a trees as input and
+return trees as output.  However, most macros require a certain kinds of
+tree node as input.  In other words, there is a type-system for trees,
+but it is not reflected in the C type-system.
+
+For safety, it is useful to configure GCC with @option{--enable-checking}.
+Although this results in a significant performance penalty (since all
+tree types are checked at run-time), and is therefore inappropriate in a
+release version, it is extremely helpful during the development process.
+
+Many macros behave as predicates.  Many, although not all, of these
+predicates end in @samp{_P}.  Do not rely on the result type of these
+macros being of any particular type.  You may, however, rely on the fact
+that the type can be compared to @code{0}, so that statements like
+@example
+if (TEST_P (t) && !TEST_P (y))
+  x = 1;
+@end example
+@noindent
+and
+@example
+int i = (TEST_P (t) != 0);
+@end example
+@noindent
+are legal.  Macros that return @code{int} values now may be changed to
+return @code{tree} values, or other pointers in the future.  Even those
+that continue to return @code{int} may return multiple nonzero codes
+where previously they returned only zero and one.  Therefore, you should
+not write code like
+@example
+if (TEST_P (t) == 1)
+@end example
+@noindent
+as this code is not guaranteed to work correctly in the future.
+
+You should not take the address of values returned by the macros or
+functions described here.  In particular, no guarantee is given that the
+values are lvalues.
+
+In general, the names of macros are all in uppercase, while the names of
+functions are entirely in lower case.  There are rare exceptions to this
+rule.  You should assume that any macro or function whose name is made
+up entirely of uppercase letters may evaluate its arguments more than
+once.  You may assume that a macro or function whose name is made up
+entirely of lowercase letters will evaluate its arguments only once.
+
+The @code{error_mark_node} is a special tree.  Its tree code is
+@code{ERROR_MARK}, but since there is only ever one node with that code,
+the usual practice is to compare the tree against
+@code{error_mark_node}.  (This test is just a test for pointer
+equality.)  If an error has occurred during front-end processing the
+flag @code{errorcount} will be set.  If the front end has encountered
+code it cannot handle, it will issue a message to the user and set
+@code{sorrycount}.  When these flags are set, any macro or function
+which normally returns a tree of a particular kind may instead return
+the @code{error_mark_node}.  Thus, if you intend to do any processing of
+erroneous code, you must be prepared to deal with the
+@code{error_mark_node}.
+
+Occasionally, a particular tree slot (like an operand to an expression,
+or a particular field in a declaration) will be referred to as
+``reserved for the back end.''  These slots are used to store RTL when
+the tree is converted to RTL for use by the GCC back end.  However, if
+that process is not taking place (e.g., if the front end is being hooked
+up to an intelligent editor), then those slots may be used by the
+back end presently in use.
+
+If you encounter situations that do not match this documentation, such
+as tree nodes of types not mentioned here, or macros documented to
+return entities of a particular kind that instead return entities of
+some different kind, you have found a bug, either in the front end or in
+the documentation.  Please report these bugs as you would any other
+bug.
+
+@menu
+* Macros and Functions::Macros and functions that can be used with all trees.
+* Identifiers::         The names of things.
+* Containers::          Lists and vectors.
+@end menu
+
+@c ---------------------------------------------------------------------
+@c Trees
+@c ---------------------------------------------------------------------
+
+@node Macros and Functions
+@subsection Trees
+@cindex tree
+
+This section is not here yet.
+
+@c ---------------------------------------------------------------------
+@c Identifiers
+@c ---------------------------------------------------------------------
+
+@node Identifiers
+@subsection Identifiers
+@cindex identifier
+@cindex name
+@tindex IDENTIFIER_NODE
+
+An @code{IDENTIFIER_NODE} represents a slightly more general concept
+that the standard C or C++ concept of identifier.  In particular, an
+@code{IDENTIFIER_NODE} may contain a @samp{$}, or other extraordinary
+characters.
+
+There are never two distinct @code{IDENTIFIER_NODE}s representing the
+same identifier.  Therefore, you may use pointer equality to compare
+@code{IDENTIFIER_NODE}s, rather than using a routine like @code{strcmp}.
+
+You can use the following macros to access identifiers:
+@ftable @code
+@item IDENTIFIER_POINTER
+The string represented by the identifier, represented as a
+@code{char*}.  This string is always @code{NUL}-terminated, and contains
+no embedded @code{NUL} characters.
+
+@item IDENTIFIER_LENGTH
+The length of the string returned by @code{IDENTIFIER_POINTER}, not
+including the trailing @code{NUL}.  This value of
+@code{IDENTIFIER_LENGTH (x)} is always the same as @code{strlen
+(IDENTIFIER_POINTER (x))}.
+
+@item IDENTIFIER_OPNAME_P
+This predicate holds if the identifier represents the name of an
+overloaded operator.  In this case, you should not depend on the
+contents of either the @code{IDENTIFIER_POINTER} or the
+@code{IDENTIFIER_LENGTH}.
+
+@item IDENTIFIER_TYPENAME_P
+This predicate holds if the identifier represents the name of a
+user-defined conversion operator.  In this case, the @code{TREE_TYPE} of
+the @code{IDENTIFIER_NODE} holds the type to which the conversion
+operator converts.
+
+@end ftable
+
+@c ---------------------------------------------------------------------
+@c Containers
+@c ---------------------------------------------------------------------
+
+@node Containers
+@subsection Containers
+@cindex container
+@cindex list
+@cindex vector
+@tindex TREE_LIST
+@tindex TREE_VEC
+@findex TREE_PURPOSE
+@findex TREE_VALUE
+@findex TREE_VEC_LENGTH
+@findex TREE_VEC_ELT
+
+Two common container data structures can be represented directly with
+tree nodes.  A @code{TREE_LIST} is a singly linked list containing two
+trees per node.  These are the @code{TREE_PURPOSE} and @code{TREE_VALUE}
+of each node.  (Often, the @code{TREE_PURPOSE} contains some kind of
+tag, or additional information, while the @code{TREE_VALUE} contains the
+majority of the payload.  In other cases, the @code{TREE_PURPOSE} is
+simply @code{NULL_TREE}, while in still others both the
+@code{TREE_PURPOSE} and @code{TREE_VALUE} are of equal stature.)  Given
+one @code{TREE_LIST} node, the next node is found by following the
+@code{TREE_CHAIN}.  If the @code{TREE_CHAIN} is @code{NULL_TREE}, then
+you have reached the end of the list.
+
+A @code{TREE_VEC} is a simple vector.  The @code{TREE_VEC_LENGTH} is an
+integer (not a tree) giving the number of nodes in the vector.  The
+nodes themselves are accessed using the @code{TREE_VEC_ELT} macro, which
+takes two arguments.  The first is the @code{TREE_VEC} in question; the
+second is an integer indicating which element in the vector is desired.
+The elements are indexed from zero.
+
+@c ---------------------------------------------------------------------
+@c Types
+@c ---------------------------------------------------------------------
+
+@node Types
+@section Types
+@cindex type
+@cindex pointer
+@cindex reference
+@cindex fundamental type
+@cindex array
+@tindex VOID_TYPE
+@tindex INTEGER_TYPE
+@tindex TYPE_MIN_VALUE
+@tindex TYPE_MAX_VALUE
+@tindex REAL_TYPE
+@tindex COMPLEX_TYPE
+@tindex ENUMERAL_TYPE
+@tindex BOOLEAN_TYPE
+@tindex POINTER_TYPE
+@tindex REFERENCE_TYPE
+@tindex FUNCTION_TYPE
+@tindex METHOD_TYPE
+@tindex ARRAY_TYPE
+@tindex RECORD_TYPE
+@tindex UNION_TYPE
+@tindex UNKNOWN_TYPE
+@tindex OFFSET_TYPE
+@tindex TYPENAME_TYPE
+@tindex TYPEOF_TYPE
+@findex CP_TYPE_QUALS
+@findex TYPE_UNQUALIFIED
+@findex TYPE_QUAL_CONST
+@findex TYPE_QUAL_VOLATILE
+@findex TYPE_QUAL_RESTRICT
+@findex TYPE_MAIN_VARIANT
+@cindex qualified type
+@findex TYPE_SIZE
+@findex TYPE_ALIGN
+@findex TYPE_PRECISION
+@findex TYPE_ARG_TYPES
+@findex TYPE_METHOD_BASETYPE
+@findex TYPE_PTRMEM_P
+@findex TYPE_OFFSET_BASETYPE
+@findex TREE_TYPE
+@findex TYPE_CONTEXT
+@findex TYPE_NAME
+@findex TYPENAME_TYPE_FULLNAME
+@findex TYPE_FIELDS
+@findex TYPE_PTROBV_P
+
+All types have corresponding tree nodes.  However, you should not assume
+that there is exactly one tree node corresponding to each type.  There
+are often several nodes each of which correspond to the same type.
+
+For the most part, different kinds of types have different tree codes.
+(For example, pointer types use a @code{POINTER_TYPE} code while arrays
+use an @code{ARRAY_TYPE} code.)  However, pointers to member functions
+use the @code{RECORD_TYPE} code.  Therefore, when writing a
+@code{switch} statement that depends on the code associated with a
+particular type, you should take care to handle pointers to member
+functions under the @code{RECORD_TYPE} case label.
+
+In C++, an array type is not qualified; rather the type of the array
+elements is qualified.  This situation is reflected in the intermediate
+representation.  The macros described here will always examine the
+qualification of the underlying element type when applied to an array
+type.  (If the element type is itself an array, then the recursion
+continues until a non-array type is found, and the qualification of this
+type is examined.)  So, for example, @code{CP_TYPE_CONST_P} will hold of
+the type @code{const int ()[7]}, denoting an array of seven @code{int}s.
+
+The following functions and macros deal with cv-qualification of types:
+@ftable @code
+@item CP_TYPE_QUALS
+This macro returns the set of type qualifiers applied to this type.
+This value is @code{TYPE_UNQUALIFIED} if no qualifiers have been
+applied.  The @code{TYPE_QUAL_CONST} bit is set if the type is
+@code{const}-qualified.  The @code{TYPE_QUAL_VOLATILE} bit is set if the
+type is @code{volatile}-qualified.  The @code{TYPE_QUAL_RESTRICT} bit is
+set if the type is @code{restrict}-qualified.
+
+@item CP_TYPE_CONST_P
+This macro holds if the type is @code{const}-qualified.
+
+@item CP_TYPE_VOLATILE_P
+This macro holds if the type is @code{volatile}-qualified.
+
+@item CP_TYPE_RESTRICT_P
+This macro holds if the type is @code{restrict}-qualified.
+
+@item CP_TYPE_CONST_NON_VOLATILE_P
+This predicate holds for a type that is @code{const}-qualified, but
+@emph{not} @code{volatile}-qualified; other cv-qualifiers are ignored as
+well: only the @code{const}-ness is tested.
+
+@item TYPE_MAIN_VARIANT
+This macro returns the unqualified version of a type.  It may be applied
+to an unqualified type, but it is not always the identity function in
+that case.
+@end ftable
+
+A few other macros and functions are usable with all types:
+@ftable @code
+@item TYPE_SIZE
+The number of bits required to represent the type, represented as an
+@code{INTEGER_CST}.  For an incomplete type, @code{TYPE_SIZE} will be
+@code{NULL_TREE}.
+
+@item TYPE_ALIGN
+The alignment of the type, in bits, represented as an @code{int}.
+
+@item TYPE_NAME
+This macro returns a declaration (in the form of a @code{TYPE_DECL}) for
+the type.  (Note this macro does @emph{not} return a
+@code{IDENTIFIER_NODE}, as you might expect, given its name!)  You can
+look at the @code{DECL_NAME} of the @code{TYPE_DECL} to obtain the
+actual name of the type.  The @code{TYPE_NAME} will be @code{NULL_TREE}
+for a type that is not a built-in type, the result of a typedef, or a
+named class type.
+
+@item CP_INTEGRAL_TYPE
+This predicate holds if the type is an integral type.  Notice that in
+C++, enumerations are @emph{not} integral types.
+
+@item ARITHMETIC_TYPE_P
+This predicate holds if the type is an integral type (in the C++ sense)
+or a floating point type.
+
+@item CLASS_TYPE_P
+This predicate holds for a class-type.
+
+@item TYPE_BUILT_IN
+This predicate holds for a built-in type.
+
+@item TYPE_PTRMEM_P
+This predicate holds if the type is a pointer to data member.
+
+@item TYPE_PTR_P
+This predicate holds if the type is a pointer type, and the pointee is
+not a data member.
+
+@item TYPE_PTRFN_P
+This predicate holds for a pointer to function type.
+
+@item TYPE_PTROB_P
+This predicate holds for a pointer to object type.  Note however that it
+does not hold for the generic pointer to object type @code{void *}.  You
+may use @code{TYPE_PTROBV_P} to test for a pointer to object type as
+well as @code{void *}.
+
+@item same_type_p
+This predicate takes two types as input, and holds if they are the same
+type.  For example, if one type is a @code{typedef} for the other, or
+both are @code{typedef}s for the same type.  This predicate also holds if
+the two trees given as input are simply copies of one another; i.e.,
+there is no difference between them at the source level, but, for
+whatever reason, a duplicate has been made in the representation.  You
+should never use @code{==} (pointer equality) to compare types; always
+use @code{same_type_p} instead.
+@end ftable
+
+Detailed below are the various kinds of types, and the macros that can
+be used to access them.  Although other kinds of types are used
+elsewhere in G++, the types described here are the only ones that you
+will encounter while examining the intermediate representation.
+
+@table @code
+@item VOID_TYPE
+Used to represent the @code{void} type.
+
+@item INTEGER_TYPE
+Used to represent the various integral types, including @code{char},
+@code{short}, @code{int}, @code{long}, and @code{long long}.  This code
+is not used for enumeration types, nor for the @code{bool} type.  Note
+that GCC's @code{CHAR_TYPE} node is @emph{not} used to represent
+@code{char}.  The @code{TYPE_PRECISION} is the number of bits used in
+the representation, represented as an @code{unsigned int}.  (Note that
+in the general case this is not the same value as @code{TYPE_SIZE};
+suppose that there were a 24-bit integer type, but that alignment
+requirements for the ABI required 32-bit alignment.  Then,
+@code{TYPE_SIZE} would be an @code{INTEGER_CST} for 32, while
+@code{TYPE_PRECISION} would be 24.)  The integer type is unsigned if
+@code{TREE_UNSIGNED} holds; otherwise, it is signed.
+
+The @code{TYPE_MIN_VALUE} is an @code{INTEGER_CST} for the smallest
+integer that may be represented by this type.  Similarly, the
+@code{TYPE_MAX_VALUE} is an @code{INTEGER_CST} for the largest integer
+that may be represented by this type.
+
+@item REAL_TYPE
+Used to represent the @code{float}, @code{double}, and @code{long
+double} types.  The number of bits in the floating-point representation
+is given by @code{TYPE_PRECISION}, as in the @code{INTEGER_TYPE} case.
+
+@item COMPLEX_TYPE
+Used to represent GCC built-in @code{__complex__} data types.  The
+@code{TREE_TYPE} is the type of the real and imaginary parts.
+
+@item ENUMERAL_TYPE
+Used to represent an enumeration type.  The @code{TYPE_PRECISION} gives
+(as an @code{int}), the number of bits used to represent the type.  If
+there are no negative enumeration constants, @code{TREE_UNSIGNED} will
+hold.  The minimum and maximum enumeration constants may be obtained
+with @code{TYPE_MIN_VALUE} and @code{TYPE_MAX_VALUE}, respectively; each
+of these macros returns an @code{INTEGER_CST}.
+
+The actual enumeration constants themselves may be obtained by looking
+at the @code{TYPE_VALUES}.  This macro will return a @code{TREE_LIST},
+containing the constants.  The @code{TREE_PURPOSE} of each node will be
+an @code{IDENTIFIER_NODE} giving the name of the constant; the
+@code{TREE_VALUE} will be an @code{INTEGER_CST} giving the value
+assigned to that constant.  These constants will appear in the order in
+which they were declared.  The @code{TREE_TYPE} of each of these
+constants will be the type of enumeration type itself.
+
+@item BOOLEAN_TYPE
+Used to represent the @code{bool} type.
+
+@item POINTER_TYPE
+Used to represent pointer types, and pointer to data member types.  The
+@code{TREE_TYPE} gives the type to which this type points.  If the type
+is a pointer to data member type, then @code{TYPE_PTRMEM_P} will hold.
+For a pointer to data member type of the form @samp{T X::*},
+@code{TYPE_PTRMEM_CLASS_TYPE} will be the type @code{X}, while
+@code{TYPE_PTRMEM_POINTED_TO_TYPE} will be the type @code{T}.
+
+@item REFERENCE_TYPE
+Used to represent reference types.  The @code{TREE_TYPE} gives the type
+to which this type refers.
+
+@item FUNCTION_TYPE
+Used to represent the type of non-member functions and of static member
+functions.  The @code{TREE_TYPE} gives the return type of the function.
+The @code{TYPE_ARG_TYPES} are a @code{TREE_LIST} of the argument types.
+The @code{TREE_VALUE} of each node in this list is the type of the
+corresponding argument; the @code{TREE_PURPOSE} is an expression for the
+default argument value, if any.  If the last node in the list is
+@code{void_list_node} (a @code{TREE_LIST} node whose @code{TREE_VALUE}
+is the @code{void_type_node}), then functions of this type do not take
+variable arguments.  Otherwise, they do take a variable number of
+arguments.
+
+Note that in C (but not in C++) a function declared like @code{void f()}
+is an unprototyped function taking a variable number of arguments; the
+@code{TYPE_ARG_TYPES} of such a function will be @code{NULL}.
+
+@item METHOD_TYPE
+Used to represent the type of a non-static member function.  Like a
+@code{FUNCTION_TYPE}, the return type is given by the @code{TREE_TYPE}.
+The type of @code{*this}, i.e., the class of which functions of this
+type are a member, is given by the @code{TYPE_METHOD_BASETYPE}.  The
+@code{TYPE_ARG_TYPES} is the parameter list, as for a
+@code{FUNCTION_TYPE}, and includes the @code{this} argument.
+
+@item ARRAY_TYPE
+Used to represent array types.  The @code{TREE_TYPE} gives the type of
+the elements in the array.  If the array-bound is present in the type,
+the @code{TYPE_DOMAIN} is an @code{INTEGER_TYPE} whose
+@code{TYPE_MIN_VALUE} and @code{TYPE_MAX_VALUE} will be the lower and
+upper bounds of the array, respectively.  The @code{TYPE_MIN_VALUE} will
+always be an @code{INTEGER_CST} for zero, while the
+@code{TYPE_MAX_VALUE} will be one less than the number of elements in
+the array, i.e., the highest value which may be used to index an element
+in the array.
+
+@item RECORD_TYPE
+Used to represent @code{struct} and @code{class} types, as well as
+pointers to member functions and similar constructs in other languages.
+@code{TYPE_FIELDS} contains the items contained in this type, each of
+which can be a @code{FIELD_DECL}, @code{VAR_DECL}, @code{CONST_DECL}, or
+@code{TYPE_DECL}.  You may not make any assumptions about the ordering
+of the fields in the type or whether one or more of them overlap.  If
+@code{TYPE_PTRMEMFUNC_P} holds, then this type is a pointer-to-member
+type.  In that case, the @code{TYPE_PTRMEMFUNC_FN_TYPE} is a
+@code{POINTER_TYPE} pointing to a @code{METHOD_TYPE}.  The
+@code{METHOD_TYPE} is the type of a function pointed to by the
+pointer-to-member function.  If @code{TYPE_PTRMEMFUNC_P} does not hold,
+this type is a class type.  For more information, see @pxref{Classes}.
+
+@item UNION_TYPE
+Used to represent @code{union} types.  Similar to @code{RECORD_TYPE}
+except that all @code{FIELD_DECL} nodes in @code{TYPE_FIELD} start at
+bit position zero.
+
+@item QUAL_UNION_TYPE
+Used to represent part of a variant record in Ada.  Similar to
+@code{UNION_TYPE} except that each @code{FIELD_DECL} has a
+@code{DECL_QUALIFIER} field, which contains a boolean expression that
+indicates whether the field is present in the object.  The type will only
+have one field, so each field's @code{DECL_QUALIFIER} is only evaluated
+if none of the expressions in the previous fields in @code{TYPE_FIELDS}
+are nonzero.  Normally these expressions will reference a field in the
+outer object using a @code{PLACEHOLDER_EXPR}.
+
+@item UNKNOWN_TYPE
+This node is used to represent a type the knowledge of which is
+insufficient for a sound processing.
+
+@item OFFSET_TYPE
+This node is used to represent a data member; for example a
+pointer-to-data-member is represented by a @code{POINTER_TYPE} whose
+@code{TREE_TYPE} is an @code{OFFSET_TYPE}.  For a data member @code{X::m}
+the @code{TYPE_OFFSET_BASETYPE} is @code{X} and the @code{TREE_TYPE} is
+the type of @code{m}.
+
+@item TYPENAME_TYPE
+Used to represent a construct of the form @code{typename T::A}.  The
+@code{TYPE_CONTEXT} is @code{T}; the @code{TYPE_NAME} is an
+@code{IDENTIFIER_NODE} for @code{A}.  If the type is specified via a
+template-id, then @code{TYPENAME_TYPE_FULLNAME} yields a
+@code{TEMPLATE_ID_EXPR}.  The @code{TREE_TYPE} is non-@code{NULL} if the
+node is implicitly generated in support for the implicit typename
+extension; in which case the @code{TREE_TYPE} is a type node for the
+base-class.
+
+@item TYPEOF_TYPE
+Used to represent the @code{__typeof__} extension.  The
+@code{TYPE_FIELDS} is the expression the type of which is being
+represented.
+@end table
+
+There are variables whose values represent some of the basic types.
+These include:
+@table @code
+@item void_type_node
+A node for @code{void}.
+
+@item integer_type_node
+A node for @code{int}.
+
+@item unsigned_type_node.
+A node for @code{unsigned int}.
+
+@item char_type_node.
+A node for @code{char}.
+@end table
+@noindent
+It may sometimes be useful to compare one of these variables with a type
+in hand, using @code{same_type_p}.
+
+@c ---------------------------------------------------------------------
+@c Scopes
+@c ---------------------------------------------------------------------
+
+@node Scopes
+@section Scopes
+@cindex namespace, class, scope
+
+The root of the entire intermediate representation is the variable
+@code{global_namespace}.  This is the namespace specified with @code{::}
+in C++ source code.  All other namespaces, types, variables, functions,
+and so forth can be found starting with this namespace.
+
+Besides namespaces, the other high-level scoping construct in C++ is the
+class.  (Throughout this manual the term @dfn{class} is used to mean the
+types referred to in the ANSI/ISO C++ Standard as classes; these include
+types defined with the @code{class}, @code{struct}, and @code{union}
+keywords.)
+
+@menu
+* Namespaces::          Member functions, types, etc.
+* Classes::             Members, bases, friends, etc.
+@end menu
+
+@c ---------------------------------------------------------------------
+@c Namespaces
+@c ---------------------------------------------------------------------
+
+@node Namespaces
+@subsection Namespaces
+@cindex namespace
+@tindex NAMESPACE_DECL
+
+A namespace is represented by a @code{NAMESPACE_DECL} node.
+
+However, except for the fact that it is distinguished as the root of the
+representation, the global namespace is no different from any other
+namespace.  Thus, in what follows, we describe namespaces generally,
+rather than the global namespace in particular.
+
+The following macros and functions can be used on a @code{NAMESPACE_DECL}:
+
+@ftable @code
+@item DECL_NAME
+This macro is used to obtain the @code{IDENTIFIER_NODE} corresponding to
+the unqualified name of the name of the namespace (@pxref{Identifiers}).
+The name of the global namespace is @samp{::}, even though in C++ the
+global namespace is unnamed.  However, you should use comparison with
+@code{global_namespace}, rather than @code{DECL_NAME} to determine
+whether or not a namespaces is the global one.  An unnamed namespace
+will have a @code{DECL_NAME} equal to @code{anonymous_namespace_name}.
+Within a single translation unit, all unnamed namespaces will have the
+same name.
+
+@item DECL_CONTEXT
+This macro returns the enclosing namespace.  The @code{DECL_CONTEXT} for
+the @code{global_namespace} is @code{NULL_TREE}.
+
+@item DECL_NAMESPACE_ALIAS
+If this declaration is for a namespace alias, then
+@code{DECL_NAMESPACE_ALIAS} is the namespace for which this one is an
+alias.
+
+Do not attempt to use @code{cp_namespace_decls} for a namespace which is
+an alias.  Instead, follow @code{DECL_NAMESPACE_ALIAS} links until you
+reach an ordinary, non-alias, namespace, and call
+@code{cp_namespace_decls} there.
+
+@item DECL_NAMESPACE_STD_P
+This predicate holds if the namespace is the special @code{::std}
+namespace.
+
+@item cp_namespace_decls
+This function will return the declarations contained in the namespace,
+including types, overloaded functions, other namespaces, and so forth.
+If there are no declarations, this function will return
+@code{NULL_TREE}.  The declarations are connected through their
+@code{TREE_CHAIN} fields.
+
+Although most entries on this list will be declarations,
+@code{TREE_LIST} nodes may also appear.  In this case, the
+@code{TREE_VALUE} will be an @code{OVERLOAD}.  The value of the
+@code{TREE_PURPOSE} is unspecified; back ends should ignore this value.
+As with the other kinds of declarations returned by
+@code{cp_namespace_decls}, the @code{TREE_CHAIN} will point to the next
+declaration in this list.
+
+For more information on the kinds of declarations that can occur on this
+list, @xref{Declarations}.  Some declarations will not appear on this
+list.  In particular, no @code{FIELD_DECL}, @code{LABEL_DECL}, or
+@code{PARM_DECL} nodes will appear here.
+
+This function cannot be used with namespaces that have
+@code{DECL_NAMESPACE_ALIAS} set.
+
+@end ftable
+
+@c ---------------------------------------------------------------------
+@c Classes
+@c ---------------------------------------------------------------------
+
+@node Classes
+@subsection Classes
+@cindex class
+@tindex RECORD_TYPE
+@tindex UNION_TYPE
+@findex CLASSTYPE_DECLARED_CLASS
+@findex TYPE_BINFO
+@findex BINFO_TYPE
+@findex TREE_VIA_PUBLIC
+@findex TREE_VIA_PROTECTED
+@findex TREE_VIA_PRIVATE
+@findex TYPE_FIELDS
+@findex TYPE_VFIELD
+@findex TYPE_METHODS
+
+A class type is represented by either a @code{RECORD_TYPE} or a
+@code{UNION_TYPE}.  A class declared with the @code{union} tag is
+represented by a @code{UNION_TYPE}, while classes declared with either
+the @code{struct} or the @code{class} tag are represented by
+@code{RECORD_TYPE}s.  You can use the @code{CLASSTYPE_DECLARED_CLASS}
+macro to discern whether or not a particular type is a @code{class} as
+opposed to a @code{struct}.  This macro will be true only for classes
+declared with the @code{class} tag.
+
+Almost all non-function members are available on the @code{TYPE_FIELDS}
+list.  Given one member, the next can be found by following the
+@code{TREE_CHAIN}.  You should not depend in any way on the order in
+which fields appear on this list.  All nodes on this list will be
+@samp{DECL} nodes.  A @code{FIELD_DECL} is used to represent a non-static
+data member, a @code{VAR_DECL} is used to represent a static data
+member, and a @code{TYPE_DECL} is used to represent a type.  Note that
+the @code{CONST_DECL} for an enumeration constant will appear on this
+list, if the enumeration type was declared in the class.  (Of course,
+the @code{TYPE_DECL} for the enumeration type will appear here as well.)
+There are no entries for base classes on this list.  In particular,
+there is no @code{FIELD_DECL} for the ``base-class portion'' of an
+object.
+
+The @code{TYPE_VFIELD} is a compiler-generated field used to point to
+virtual function tables.  It may or may not appear on the
+@code{TYPE_FIELDS} list.  However, back ends should handle the
+@code{TYPE_VFIELD} just like all the entries on the @code{TYPE_FIELDS}
+list.
+
+The function members are available on the @code{TYPE_METHODS} list.
+Again, subsequent members are found by following the @code{TREE_CHAIN}
+field.  If a function is overloaded, each of the overloaded functions
+appears; no @code{OVERLOAD} nodes appear on the @code{TYPE_METHODS}
+list.  Implicitly declared functions (including default constructors,
+copy constructors, assignment operators, and destructors) will appear on
+this list as well.
+
+Every class has an associated @dfn{binfo}, which can be obtained with
+@code{TYPE_BINFO}.  Binfos are used to represent base-classes.  The
+binfo given by @code{TYPE_BINFO} is the degenerate case, whereby every
+class is considered to be its own base-class.  The base classes for a
+particular binfo can be obtained with @code{BINFO_BASETYPES}.  These
+base-classes are themselves binfos.  The class type associated with a
+binfo is given by @code{BINFO_TYPE}.  It is always the case that
+@code{BINFO_TYPE (TYPE_BINFO (x))} is the same type as @code{x}, up to
+qualifiers.  However, it is not always the case that @code{TYPE_BINFO
+(BINFO_TYPE (y))} is always the same binfo as @code{y}.  The reason is
+that if @code{y} is a binfo representing a base-class @code{B} of a
+derived class @code{D}, then @code{BINFO_TYPE (y)} will be @code{B}, and
+@code{TYPE_INFO (BINFO_TYPE (y))} will be @code{B} as its own
+base-class, rather than as a base-class of @code{D}.
+
+The @code{BINFO_BASETYPES} is a @code{TREE_VEC} (@pxref{Containers}).
+Base types appear in left-to-right order in this vector.  You can tell
+whether or @code{public}, @code{protected}, or @code{private}
+inheritance was used by using the @code{TREE_VIA_PUBLIC},
+@code{TREE_VIA_PROTECTED}, and @code{TREE_VIA_PRIVATE} macros.  Each of
+these macros takes a @code{BINFO} and is true if and only if the
+indicated kind of inheritance was used.  If @code{TREE_VIA_VIRTUAL}
+holds of a binfo, then its @code{BINFO_TYPE} was inherited from
+virtually.
+
+The following macros can be used on a tree node representing a class-type.
+
+@ftable @code
+@item LOCAL_CLASS_P
+This predicate holds if the class is local class @emph{i.e.} declared
+inside a function body.
+
+@item TYPE_POLYMORPHIC_P
+This predicate holds if the class has at least one virtual function
+(declared or inherited).
+
+@item TYPE_HAS_DEFAULT_CONSTRUCTOR
+This predicate holds whenever its argument represents a class-type with
+default constructor.
+
+@item CLASSTYPE_HAS_MUTABLE
+@item TYPE_HAS_MUTABLE_P
+These predicates hold for a class-type having a mutable data member.
+
+@item CLASSTYPE_NON_POD_P
+This predicate holds only for class-types that are not PODs.
+
+@item TYPE_HAS_NEW_OPERATOR
+This predicate holds for a class-type that defines
+@code{operator new}.
+
+@item TYPE_HAS_ARRAY_NEW_OPERATOR
+This predicate holds for a class-type for which
+@code{operator new[]} is defined.
+
+@item TYPE_OVERLOADS_CALL_EXPR
+This predicate holds for class-type for which the function call
+@code{operator()} is overloaded.
+
+@item TYPE_OVERLOADS_ARRAY_REF
+This predicate holds for a class-type that overloads
+@code{operator[]}
+
+@item TYPE_OVERLOADS_ARROW
+This predicate holds for a class-type for which @code{operator->} is
+overloaded.
+
+@end ftable
+
+@c ---------------------------------------------------------------------
+@c Declarations
+@c ---------------------------------------------------------------------
+
+@node Declarations
+@section Declarations
+@cindex declaration
+@cindex variable
+@cindex type declaration
+@tindex LABEL_DECL
+@tindex CONST_DECL
+@tindex TYPE_DECL
+@tindex VAR_DECL
+@tindex PARM_DECL
+@tindex FIELD_DECL
+@tindex NAMESPACE_DECL
+@tindex RESULT_DECL
+@tindex TEMPLATE_DECL
+@tindex THUNK_DECL
+@tindex USING_DECL
+@findex THUNK_DELTA
+@findex DECL_INITIAL
+@findex DECL_SIZE
+@findex DECL_ALIGN
+@findex DECL_EXTERNAL
+
+This section covers the various kinds of declarations that appear in the
+internal representation, except for declarations of functions
+(represented by @code{FUNCTION_DECL} nodes), which are described in
+@ref{Functions}.
+
+Some macros can be used with any kind of declaration.  These include:
+@ftable @code
+@item DECL_NAME
+This macro returns an @code{IDENTIFIER_NODE} giving the name of the
+entity.
+
+@item TREE_TYPE
+This macro returns the type of the entity declared.
+
+@item DECL_SOURCE_FILE
+This macro returns the name of the file in which the entity was
+declared, as a @code{char*}.  For an entity declared implicitly by the
+compiler (like @code{__builtin_memcpy}), this will be the string
+@code{"<internal>"}.
+
+@item DECL_SOURCE_LINE
+This macro returns the line number at which the entity was declared, as
+an @code{int}.
+
+@item DECL_ARTIFICIAL
+This predicate holds if the declaration was implicitly generated by the
+compiler.  For example, this predicate will hold of an implicitly
+declared member function, or of the @code{TYPE_DECL} implicitly
+generated for a class type.  Recall that in C++ code like:
+@example
+struct S @{@};
+@end example
+@noindent
+is roughly equivalent to C code like:
+@example
+struct S @{@};
+typedef struct S S;
+@end example
+The implicitly generated @code{typedef} declaration is represented by a
+@code{TYPE_DECL} for which @code{DECL_ARTIFICIAL} holds.
+
+@item DECL_NAMESPACE_SCOPE_P
+This predicate holds if the entity was declared at a namespace scope.
+
+@item DECL_CLASS_SCOPE_P
+This predicate holds if the entity was declared at a class scope.
+
+@item DECL_FUNCTION_SCOPE_P
+This predicate holds if the entity was declared inside a function
+body.
+
+@end ftable
+
+The various kinds of declarations include:
+@table @code
+@item LABEL_DECL
+These nodes are used to represent labels in function bodies.  For more
+information, see @ref{Functions}.  These nodes only appear in block
+scopes.
+
+@item CONST_DECL
+These nodes are used to represent enumeration constants.  The value of
+the constant is given by @code{DECL_INITIAL} which will be an
+@code{INTEGER_CST} with the same type as the @code{TREE_TYPE} of the
+@code{CONST_DECL}, i.e., an @code{ENUMERAL_TYPE}.
+
+@item RESULT_DECL
+These nodes represent the value returned by a function.  When a value is
+assigned to a @code{RESULT_DECL}, that indicates that the value should
+be returned, via bitwise copy, by the function.  You can use
+@code{DECL_SIZE} and @code{DECL_ALIGN} on a @code{RESULT_DECL}, just as
+with a @code{VAR_DECL}.
+
+@item TYPE_DECL
+These nodes represent @code{typedef} declarations.  The @code{TREE_TYPE}
+is the type declared to have the name given by @code{DECL_NAME}.  In
+some cases, there is no associated name.
+
+@item VAR_DECL
+These nodes represent variables with namespace or block scope, as well
+as static data members.  The @code{DECL_SIZE} and @code{DECL_ALIGN} are
+analogous to @code{TYPE_SIZE} and @code{TYPE_ALIGN}.  For a declaration,
+you should always use the @code{DECL_SIZE} and @code{DECL_ALIGN} rather
+than the @code{TYPE_SIZE} and @code{TYPE_ALIGN} given by the
+@code{TREE_TYPE}, since special attributes may have been applied to the
+variable to give it a particular size and alignment.  You may use the
+predicates @code{DECL_THIS_STATIC} or @code{DECL_THIS_EXTERN} to test
+whether the storage class specifiers @code{static} or @code{extern} were
+used to declare a variable.
+
+If this variable is initialized (but does not require a constructor),
+the @code{DECL_INITIAL} will be an expression for the initializer.  The
+initializer should be evaluated, and a bitwise copy into the variable
+performed.  If the @code{DECL_INITIAL} is the @code{error_mark_node},
+there is an initializer, but it is given by an explicit statement later
+in the code; no bitwise copy is required.
+
+GCC provides an extension that allows either automatic variables, or
+global variables, to be placed in particular registers.  This extension
+is being used for a particular @code{VAR_DECL} if @code{DECL_REGISTER}
+holds for the @code{VAR_DECL}, and if @code{DECL_ASSEMBLER_NAME} is not
+equal to @code{DECL_NAME}.  In that case, @code{DECL_ASSEMBLER_NAME} is
+the name of the register into which the variable will be placed.
+
+@item PARM_DECL
+Used to represent a parameter to a function.  Treat these nodes
+similarly to @code{VAR_DECL} nodes.  These nodes only appear in the
+@code{DECL_ARGUMENTS} for a @code{FUNCTION_DECL}.
+
+The @code{DECL_ARG_TYPE} for a @code{PARM_DECL} is the type that will
+actually be used when a value is passed to this function.  It may be a
+wider type than the @code{TREE_TYPE} of the parameter; for example, the
+ordinary type might be @code{short} while the @code{DECL_ARG_TYPE} is
+@code{int}.
+
+@item FIELD_DECL
+These nodes represent non-static data members.  The @code{DECL_SIZE} and
+@code{DECL_ALIGN} behave as for @code{VAR_DECL} nodes.  The
+@code{DECL_FIELD_BITPOS} gives the first bit used for this field, as an
+@code{INTEGER_CST}.  These values are indexed from zero, where zero
+indicates the first bit in the object.
+
+If @code{DECL_C_BIT_FIELD} holds, this field is a bit-field.
+
+@item NAMESPACE_DECL
+@xref{Namespaces}.
+
+@item TEMPLATE_DECL
+
+These nodes are used to represent class, function, and variable (static
+data member) templates.  The @code{DECL_TEMPLATE_SPECIALIZATIONS} are a
+@code{TREE_LIST}.  The @code{TREE_VALUE} of each node in the list is a
+@code{TEMPLATE_DECL}s or @code{FUNCTION_DECL}s representing
+specializations (including instantiations) of this template.  Back ends
+can safely ignore @code{TEMPLATE_DECL}s, but should examine
+@code{FUNCTION_DECL} nodes on the specializations list just as they
+would ordinary @code{FUNCTION_DECL} nodes.
+
+For a class template, the @code{DECL_TEMPLATE_INSTANTIATIONS} list
+contains the instantiations.  The @code{TREE_VALUE} of each node is an
+instantiation of the class.  The @code{DECL_TEMPLATE_SPECIALIZATIONS}
+contains partial specializations of the class.
+
+@item USING_DECL
+
+Back ends can safely ignore these nodes.
+
+@end table
+
+@c ---------------------------------------------------------------------
+@c Functions
+@c ---------------------------------------------------------------------
+
+@node Functions
+@section Functions
+@cindex function
+@tindex FUNCTION_DECL
+@tindex OVERLOAD
+@findex OVL_CURRENT
+@findex OVL_NEXT
+
+A function is represented by a @code{FUNCTION_DECL} node.  A set of
+overloaded functions is sometimes represented by a @code{OVERLOAD} node.
+
+An @code{OVERLOAD} node is not a declaration, so none of the
+@samp{DECL_} macros should be used on an @code{OVERLOAD}.  An
+@code{OVERLOAD} node is similar to a @code{TREE_LIST}.  Use
+@code{OVL_CURRENT} to get the function associated with an
+@code{OVERLOAD} node; use @code{OVL_NEXT} to get the next
+@code{OVERLOAD} node in the list of overloaded functions.  The macros
+@code{OVL_CURRENT} and @code{OVL_NEXT} are actually polymorphic; you can
+use them to work with @code{FUNCTION_DECL} nodes as well as with
+overloads.  In the case of a @code{FUNCTION_DECL}, @code{OVL_CURRENT}
+will always return the function itself, and @code{OVL_NEXT} will always
+be @code{NULL_TREE}.
+
+To determine the scope of a function, you can use the
+@code{DECL_REAL_CONTEXT} macro.  This macro will return the class
+(either a @code{RECORD_TYPE} or a @code{UNION_TYPE}) or namespace (a
+@code{NAMESPACE_DECL}) of which the function is a member.  For a virtual
+function, this macro returns the class in which the function was
+actually defined, not the base class in which the virtual declaration
+occurred.  If a friend function is defined in a class scope, the
+@code{DECL_CLASS_CONTEXT} macro can be used to determine the class in
+which it was defined.  For example, in
+@example
+class C @{ friend void f() @{@} @};
+@end example
+the @code{DECL_REAL_CONTEXT} for @code{f} will be the
+@code{global_namespace}, but the @code{DECL_CLASS_CONTEXT} will be the
+@code{RECORD_TYPE} for @code{C}.
+
+The @code{DECL_REAL_CONTEXT} and @code{DECL_CLASS_CONTEXT} are not
+available in C; instead you should simply use @code{DECL_CONTEXT}.  In C,
+the @code{DECL_CONTEXT} for a function maybe another function.  This
+representation indicates that the GNU nested function extension is in
+use.  For details on the semantics of nested functions, see the GCC
+Manual.  The nested function can refer to local variables in its
+containing function.  Such references are not explicitly marked in the
+tree structure; back ends must look at the @code{DECL_CONTEXT} for the
+referenced @code{VAR_DECL}.  If the @code{DECL_CONTEXT} for the
+referenced @code{VAR_DECL} is not the same as the function currently
+being processed, and neither @code{DECL_EXTERNAL} nor @code{DECL_STATIC}
+hold, then the reference is to a local variable in a containing
+function, and the back end must take appropriate action.
+
+@menu
+* Function Basics::     Function names, linkage, and so forth.
+* Function Bodies::     The statements that make up a function body.
+@end menu
+
+@c ---------------------------------------------------------------------
+@c Function Basics
+@c ---------------------------------------------------------------------
+
+@node Function Basics
+@subsection Function Basics
+@cindex constructor
+@cindex destructor
+@cindex copy constructor
+@cindex assignment operator
+@cindex linkage
+@findex DECL_NAME
+@findex DECL_ASSEMBLER_NAME
+@findex TREE_PUBLIC
+@findex DECL_LINKONCE_P
+@findex DECL_FUNCTION_MEMBER_P
+@findex DECL_CONSTRUCTOR_P
+@findex DECL_DESTRUCTOR_P
+@findex DECL_OVERLOADED_OPERATOR_P
+@findex DECL_CONV_FN_P
+@findex DECL_ARTIFICIAL
+@findex DECL_GLOBAL_CTOR_P
+@findex DECL_GLOBAL_DTOR_P
+@findex GLOBAL_INIT_PRIORITY
+
+The following macros and functions can be used on a @code{FUNCTION_DECL}:
+@ftable @code
+@item DECL_MAIN_P
+This predicate holds for a function that is the program entry point
+@code{::code}.
+
+@item DECL_NAME
+This macro returns the unqualified name of the function, as an
+@code{IDENTIFIER_NODE}.  For an instantiation of a function template,
+the @code{DECL_NAME} is the unqualified name of the template, not
+something like @code{f<int>}.  The value of @code{DECL_NAME} is
+undefined when used on a constructor, destructor, overloaded operator,
+or type-conversion operator, or any function that is implicitly
+generated by the compiler.  See below for macros that can be used to
+distinguish these cases.
+
+@item DECL_ASSEMBLER_NAME
+This macro returns the mangled name of the function, also an
+@code{IDENTIFIER_NODE}.  This name does not contain leading underscores
+on systems that prefix all identifiers with underscores.  The mangled
+name is computed in the same way on all platforms; if special processing
+is required to deal with the object file format used on a particular
+platform, it is the responsibility of the back end to perform those
+modifications.  (Of course, the back end should not modify
+@code{DECL_ASSEMBLER_NAME} itself.)
+
+@item DECL_EXTERNAL
+This predicate holds if the function is undefined.
+
+@item TREE_PUBLIC
+This predicate holds if the function has external linkage.
+
+@item DECL_LOCAL_FUNCTION_P
+This predicate holds if the function was declared at block scope, even
+though it has a global scope.
+
+@item DECL_ANTICIPATED
+This predicate holds if the function is a built-in function but its
+prototype is not yet explicitly declared.
+
+@item DECL_EXTERN_C_FUNCTION_P
+This predicate holds if the function is declared as an
+`@code{extern "C"}' function.
+
+@item DECL_LINKONCE_P
+This macro holds if multiple copies of this function may be emitted in
+various translation units.  It is the responsibility of the linker to
+merge the various copies.  Template instantiations are the most common
+example of functions for which @code{DECL_LINKONCE_P} holds; G++
+instantiates needed templates in all translation units which require them,
+and then relies on the linker to remove duplicate instantiations.
+
+FIXME: This macro is not yet implemented.
+
+@item DECL_FUNCTION_MEMBER_P
+This macro holds if the function is a member of a class, rather than a
+member of a namespace.
+
+@item DECL_STATIC_FUNCTION_P
+This predicate holds if the function a static member function.
+
+@item DECL_NONSTATIC_MEMBER_FUNCTION_P
+This macro holds for a non-static member function.
+
+@item DECL_CONST_MEMFUNC_P
+This predicate holds for a @code{const}-member function.
+
+@item DECL_VOLATILE_MEMFUNC_P
+This predicate holds for a @code{volatile}-member function.
+
+@item DECL_CONSTRUCTOR_P
+This macro holds if the function is a constructor.
+
+@item DECL_NONCONVERTING_P
+This predicate holds if the constructor is a non-converting constructor.
+
+@item DECL_COMPLETE_CONSTRUCTOR_P
+This predicate holds for a function which is a constructor for an object
+of a complete type.
+
+@item DECL_BASE_CONSTRUCTOR_P
+This predicate holds for a function which is a constructor for a base
+class sub-object.
+
+@item DECL_COPY_CONSTRUCTOR_P
+This predicate holds for a function which is a copy-constructor.
+
+@item DECL_DESTRUCTOR_P
+This macro holds if the function is a destructor.
+
+@item DECL_COMPLETE_DESTRUCTOR_P
+This predicate holds if the function is the destructor for an object a
+complete type.
+
+@item DECL_OVERLOADED_OPERATOR_P
+This macro holds if the function is an overloaded operator.
+
+@item DECL_CONV_FN_P
+This macro holds if the function is a type-conversion operator.
+
+@item DECL_GLOBAL_CTOR_P
+This predicate holds if the function is a file-scope initialization
+function.
+
+@item DECL_GLOBAL_DTOR_P
+This predicate holds if the function is a file-scope finalization
+function.
+
+@item DECL_THUNK_P
+This predicate holds if the function is a thunk.
+
+These functions represent stub code that adjusts the @code{this} pointer
+and then jumps to another function.  When the jumped-to function
+returns, control is transferred directly to the caller, without
+returning to the thunk.  The first parameter to the thunk is always the
+@code{this} pointer; the thunk should add @code{THUNK_DELTA} to this
+value.  (The @code{THUNK_DELTA} is an @code{int}, not an
+@code{INTEGER_CST}.)
+
+Then, if @code{THUNK_VCALL_OFFSET} (an @code{INTEGER_CST}) is nonzero
+the adjusted @code{this} pointer must be adjusted again.  The complete
+calculation is given by the following pseudo-code:
+
+@example
+this += THUNK_DELTA
+if (THUNK_VCALL_OFFSET)
+  this += (*((ptrdiff_t **) this))[THUNK_VCALL_OFFSET]
+@end example
+
+Finally, the thunk should jump to the location given
+by @code{DECL_INITIAL}; this will always be an expression for the
+address of a function.
+
+@item DECL_NON_THUNK_FUNCTION_P
+This predicate holds if the function is @emph{not} a thunk function.
+
+@item GLOBAL_INIT_PRIORITY
+If either @code{DECL_GLOBAL_CTOR_P} or @code{DECL_GLOBAL_DTOR_P} holds,
+then this gives the initialization priority for the function.  The
+linker will arrange that all functions for which
+@code{DECL_GLOBAL_CTOR_P} holds are run in increasing order of priority
+before @code{main} is called.  When the program exits, all functions for
+which @code{DECL_GLOBAL_DTOR_P} holds are run in the reverse order.
+
+@item DECL_ARTIFICIAL
+This macro holds if the function was implicitly generated by the
+compiler, rather than explicitly declared.  In addition to implicitly
+generated class member functions, this macro holds for the special
+functions created to implement static initialization and destruction, to
+compute run-time type information, and so forth.
+
+@item DECL_ARGUMENTS
+This macro returns the @code{PARM_DECL} for the first argument to the
+function.  Subsequent @code{PARM_DECL} nodes can be obtained by
+following the @code{TREE_CHAIN} links.
+
+@item DECL_RESULT
+This macro returns the @code{RESULT_DECL} for the function.
+
+@item TREE_TYPE
+This macro returns the @code{FUNCTION_TYPE} or @code{METHOD_TYPE} for
+the function.
+
+@item TYPE_RAISES_EXCEPTIONS
+This macro returns the list of exceptions that a (member-)function can
+raise.  The returned list, if non @code{NULL}, is comprised of nodes
+whose @code{TREE_VALUE} represents a type.
+
+@item TYPE_NOTHROW_P
+This predicate holds when the exception-specification of its arguments
+if of the form `@code{()}'.
+
+@item DECL_ARRAY_DELETE_OPERATOR_P
+This predicate holds if the function an overloaded
+@code{operator delete[]}.
+
+@end ftable
+
+@c ---------------------------------------------------------------------
+@c Function Bodies
+@c ---------------------------------------------------------------------
+
+@node Function Bodies
+@subsection Function Bodies
+@cindex function body
+@cindex statements
+@tindex ASM_STMT
+@findex ASM_STRING
+@findex ASM_CV_QUAL
+@findex ASM_INPUTS
+@findex ASM_OUTPUTS
+@findex ASM_CLOBBERS
+@tindex BREAK_STMT
+@tindex CLEANUP_STMT
+@findex CLEANUP_DECL
+@findex CLEANUP_EXPR
+@tindex COMPOUND_STMT
+@findex COMPOUND_BODY
+@tindex CONTINUE_STMT
+@tindex DECL_STMT
+@findex DECL_STMT_DECL
+@tindex DO_STMT
+@findex DO_BODY
+@findex DO_COND
+@tindex EMPTY_CLASS_EXPR
+@tindex EXPR_STMT
+@findex EXPR_STMT_EXPR
+@tindex FOR_STMT
+@findex FOR_INIT_STMT
+@findex FOR_COND
+@findex FOR_EXPR
+@findex FOR_BODY
+@tindex FILE_STMT
+@findex FILE_STMT_FILENAME
+@tindex GOTO_STMT
+@findex GOTO_DESTINATION
+@findex GOTO_FAKE_P
+@tindex HANDLER
+@tindex IF_STMT
+@findex IF_COND
+@findex THEN_CLAUSE
+@findex ELSE_CLAUSE
+@tindex LABEL_STMT
+@tindex LABEL_STMT_LABEL
+@tindex RETURN_INIT
+@tindex RETURN_STMT
+@findex RETURN_EXPR
+@tindex SCOPE_STMT
+@findex SCOPE_BEGIN_P
+@findex SCOPE_END_P
+@findex SCOPE_NULLIFIED_P
+@tindex SUBOBJECT
+@findex SUBOBJECT_CLEANUP
+@tindex SWITCH_STMT
+@findex SWITCH_COND
+@findex SWITCH_BODY
+@tindex TRY_BLOCK
+@findex TRY_STMTS
+@findex TRY_HANDLERS
+@findex HANDLER_PARMS
+@findex HANDLER_BODY
+@findex USING_STMT
+@tindex WHILE_STMT
+@findex WHILE_BODY
+@findex WHILE_COND
+
+A function that has a definition in the current translation unit will
+have a non-@code{NULL} @code{DECL_INITIAL}.  However, back ends should not make
+use of the particular value given by @code{DECL_INITIAL}.
+
+The @code{DECL_SAVED_TREE} macro will give the complete body of the
+function.  This node will usually be a @code{COMPOUND_STMT} representing
+the outermost block of the function, but it may also be a
+@code{TRY_BLOCK}, a @code{RETURN_INIT}, or any other valid statement.
+
+@subsubsection Statements
+
+There are tree nodes corresponding to all of the source-level statement
+constructs.  These are enumerated here, together with a list of the
+various macros that can be used to obtain information about them.  There
+are a few macros that can be used with all statements:
+
+@ftable @code
+@item STMT_LINENO
+This macro returns the line number for the statement.  If the statement
+spans multiple lines, this value will be the number of the first line on
+which the statement occurs.  Although we mention @code{CASE_LABEL} below
+as if it were a statement, they do not allow the use of
+@code{STMT_LINENO}.  There is no way to obtain the line number for a
+@code{CASE_LABEL}.
+
+Statements do not contain information about
+the file from which they came; that information is implicit in the
+@code{FUNCTION_DECL} from which the statements originate.
+
+@item STMT_IS_FULL_EXPR_P
+In C++, statements normally constitute ``full expressions''; temporaries
+created during a statement are destroyed when the statement is complete.
+However, G++ sometimes represents expressions by statements; these
+statements will not have @code{STMT_IS_FULL_EXPR_P} set.  Temporaries
+created during such statements should be destroyed when the innermost
+enclosing statement with @code{STMT_IS_FULL_EXPR_P} set is exited.
+
+@end ftable
+
+Here is the list of the various statement nodes, and the macros used to
+access them.  This documentation describes the use of these nodes in
+non-template functions (including instantiations of template functions).
+In template functions, the same nodes are used, but sometimes in
+slightly different ways.
+
+Many of the statements have substatements.  For example, a @code{while}
+loop will have a body, which is itself a statement.  If the substatement
+is @code{NULL_TREE}, it is considered equivalent to a statement
+consisting of a single @code{;}, i.e., an expression statement in which
+the expression has been omitted.  A substatement may in fact be a list
+of statements, connected via their @code{TREE_CHAIN}s.  So, you should
+always process the statement tree by looping over substatements, like
+this:
+@example
+void process_stmt (stmt)
+     tree stmt;
+@{
+  while (stmt)
+    @{
+      switch (TREE_CODE (stmt))
+        @{
+        case IF_STMT:
+          process_stmt (THEN_CLAUSE (stmt));
+          /* More processing here.  */
+          break;
+
+        @dots{}
+        @}
+
+      stmt = TREE_CHAIN (stmt);
+    @}
+@}
+@end example
+In other words, while the @code{then} clause of an @code{if} statement
+in C++ can be only one statement (although that one statement may be a
+compound statement), the intermediate representation will sometimes use
+several statements chained together.
+
+@table @code
+@item ASM_STMT
+
+Used to represent an inline assembly statement.  For an inline assembly
+statement like:
+@example
+asm ("mov x, y");
+@end example
+The @code{ASM_STRING} macro will return a @code{STRING_CST} node for
+@code{"mov x, y"}.  If the original statement made use of the
+extended-assembly syntax, then @code{ASM_OUTPUTS},
+@code{ASM_INPUTS}, and @code{ASM_CLOBBERS} will be the outputs, inputs,
+and clobbers for the statement, represented as @code{STRING_CST} nodes.
+The extended-assembly syntax looks like:
+@example
+asm ("fsinx %1,%0" : "=f" (result) : "f" (angle));
+@end example
+The first string is the @code{ASM_STRING}, containing the instruction
+template.  The next two strings are the output and inputs, respectively;
+this statement has no clobbers.  As this example indicates, ``plain''
+assembly statements are merely a special case of extended assembly
+statements; they have no cv-qualifiers, outputs, inputs, or clobbers.
+All of the strings will be @code{NUL}-terminated, and will contain no
+embedded @code{NUL}-characters.
+
+If the assembly statement is declared @code{volatile}, or if the
+statement was not an extended assembly statement, and is therefore
+implicitly volatile, then the predicate @code{ASM_VOLATILE_P} will hold
+of the @code{ASM_STMT}.
+
+@item BREAK_STMT
+
+Used to represent a @code{break} statement.  There are no additional
+fields.
+
+@item CASE_LABEL
+
+Use to represent a @code{case} label, range of @code{case} labels, or a
+@code{default} label.  If @code{CASE_LOW} is @code{NULL_TREE}, then this is a
+@code{default} label.  Otherwise, if @code{CASE_HIGH} is @code{NULL_TREE}, then
+this is an ordinary @code{case} label.  In this case, @code{CASE_LOW} is
+an expression giving the value of the label.  Both @code{CASE_LOW} and
+@code{CASE_HIGH} are @code{INTEGER_CST} nodes.  These values will have
+the same type as the condition expression in the switch statement.
+
+Otherwise, if both @code{CASE_LOW} and @code{CASE_HIGH} are defined, the
+statement is a range of case labels.  Such statements originate with the
+extension that allows users to write things of the form:
+@example
+case 2 ... 5:
+@end example
+The first value will be @code{CASE_LOW}, while the second will be
+@code{CASE_HIGH}.
+
+@item CLEANUP_STMT
+
+Used to represent an action that should take place upon exit from the
+enclosing scope.  Typically, these actions are calls to destructors for
+local objects, but back ends cannot rely on this fact.  If these nodes
+are in fact representing such destructors, @code{CLEANUP_DECL} will be
+the @code{VAR_DECL} destroyed.  Otherwise, @code{CLEANUP_DECL} will be
+@code{NULL_TREE}.  In any case, the @code{CLEANUP_EXPR} is the
+expression to execute.  The cleanups executed on exit from a scope
+should be run in the reverse order of the order in which the associated
+@code{CLEANUP_STMT}s were encountered.
+
+@item COMPOUND_STMT
+
+Used to represent a brace-enclosed block.  The first substatement is
+given by @code{COMPOUND_BODY}.  Subsequent substatements are found by
+following the @code{TREE_CHAIN} link from one substatement to the next.
+The @code{COMPOUND_BODY} will be @code{NULL_TREE} if there are no
+substatements.
+
+@item CONTINUE_STMT
+
+Used to represent a @code{continue} statement.  There are no additional
+fields.
+
+@item CTOR_STMT
+
+Used to mark the beginning (if @code{CTOR_BEGIN_P} holds) or end (if
+@code{CTOR_END_P} holds of the main body of a constructor.  See also
+@code{SUBOBJECT} for more information on how to use these nodes.
+
+@item DECL_STMT
+
+Used to represent a local declaration.  The @code{DECL_STMT_DECL} macro
+can be used to obtain the entity declared.  This declaration may be a
+@code{LABEL_DECL}, indicating that the label declared is a local label.
+(As an extension, GCC allows the declaration of labels with scope.)  In
+C, this declaration may be a @code{FUNCTION_DECL}, indicating the
+use of the GCC nested function extension.  For more information,
+@pxref{Functions}.
+
+@item DO_STMT
+
+Used to represent a @code{do} loop.  The body of the loop is given by
+@code{DO_BODY} while the termination condition for the loop is given by
+@code{DO_COND}.  The condition for a @code{do}-statement is always an
+expression.
+
+@item EMPTY_CLASS_EXPR
+
+Used to represent a temporary object of a class with no data whose
+address is never taken.  (All such objects are interchangeable.)  The
+@code{TREE_TYPE} represents the type of the object.
+
+@item EXPR_STMT
+
+Used to represent an expression statement.  Use @code{EXPR_STMT_EXPR} to
+obtain the expression.
+
+@item FILE_STMT
+
+Used to record a change in filename within the body of a function.
+Use @code{FILE_STMT_FILENAME} to obtain the new filename.
+
+@item FOR_STMT
+
+Used to represent a @code{for} statement.  The @code{FOR_INIT_STMT} is
+the initialization statement for the loop.  The @code{FOR_COND} is the
+termination condition.  The @code{FOR_EXPR} is the expression executed
+right before the @code{FOR_COND} on each loop iteration; often, this
+expression increments a counter.  The body of the loop is given by
+@code{FOR_BODY}.  Note that @code{FOR_INIT_STMT} and @code{FOR_BODY}
+return statements, while @code{FOR_COND} and @code{FOR_EXPR} return
+expressions.
+
+@item GOTO_STMT
+
+Used to represent a @code{goto} statement.  The @code{GOTO_DESTINATION} will
+usually be a @code{LABEL_DECL}.  However, if the ``computed goto'' extension
+has been used, the @code{GOTO_DESTINATION} will be an arbitrary expression
+indicating the destination.  This expression will always have pointer type.
+Additionally the @code{GOTO_FAKE_P} flag is set whenever the goto statement
+does not come from source code, but it is generated implicitly by the compiler.
+This is used for branch prediction.
+
+@item HANDLER
+
+Used to represent a C++ @code{catch} block.  The @code{HANDLER_TYPE}
+is the type of exception that will be caught by this handler; it is
+equal (by pointer equality) to @code{CATCH_ALL_TYPE} if this handler
+is for all types.  @code{HANDLER_PARMS} is the @code{DECL_STMT} for
+the catch parameter, and @code{HANDLER_BODY} is the
+@code{COMPOUND_STMT} for the block itself.
+
+@item IF_STMT
+
+Used to represent an @code{if} statement.  The @code{IF_COND} is the
+expression.
+
+If the condition is a @code{TREE_LIST}, then the @code{TREE_PURPOSE} is
+a statement (usually a @code{DECL_STMT}).  Each time the condition is
+evaluated, the statement should be executed.  Then, the
+@code{TREE_VALUE} should be used as the conditional expression itself.
+This representation is used to handle C++ code like this:
+
+@example
+if (int i = 7) @dots{}
+@end example
+
+where there is a new local variable (or variables) declared within the
+condition.
+
+The @code{THEN_CLAUSE} represents the statement given by the @code{then}
+condition, while the @code{ELSE_CLAUSE} represents the statement given
+by the @code{else} condition.
+
+@item LABEL_STMT
+
+Used to represent a label.  The @code{LABEL_DECL} declared by this
+statement can be obtained with the @code{LABEL_STMT_LABEL} macro.  The
+@code{IDENTIFIER_NODE} giving the name of the label can be obtained from
+the @code{LABEL_DECL} with @code{DECL_NAME}.
+
+@item RETURN_INIT
+
+If the function uses the G++ ``named return value'' extension, meaning
+that the function has been defined like:
+@example
+S f(int) return s @{@dots{}@}
+@end example
+then there will be a @code{RETURN_INIT}.  There is never a named
+returned value for a constructor.  The first argument to the
+@code{RETURN_INIT} is the name of the object returned; the second
+argument is the initializer for the object.  The object is initialized
+when the @code{RETURN_INIT} is encountered.  The object referred to is
+the actual object returned; this extension is a manual way of doing the
+``return-value optimization.''  Therefore, the object must actually be
+constructed in the place where the object will be returned.
+
+@item RETURN_STMT
+
+Used to represent a @code{return} statement.  The @code{RETURN_EXPR} is
+the expression returned; it will be @code{NULL_TREE} if the statement
+was just
+@example
+return;
+@end example
+
+@item SCOPE_STMT
+
+A scope-statement represents the beginning or end of a scope.  If
+@code{SCOPE_BEGIN_P} holds, this statement represents the beginning of a
+scope; if @code{SCOPE_END_P} holds this statement represents the end of
+a scope.  On exit from a scope, all cleanups from @code{CLEANUP_STMT}s
+occurring in the scope must be run, in reverse order to the order in
+which they were encountered.  If @code{SCOPE_NULLIFIED_P} or
+@code{SCOPE_NO_CLEANUPS_P} holds of the scope, back ends should behave
+as if the @code{SCOPE_STMT} were not present at all.
+
+@item SUBOBJECT
+
+In a constructor, these nodes are used to mark the point at which a
+subobject of @code{this} is fully constructed.  If, after this point, an
+exception is thrown before a @code{CTOR_STMT} with @code{CTOR_END_P} set
+is encountered, the @code{SUBOBJECT_CLEANUP} must be executed.  The
+cleanups must be executed in the reverse order in which they appear.
+
+@item SWITCH_STMT
+
+Used to represent a @code{switch} statement.  The @code{SWITCH_COND} is
+the expression on which the switch is occurring.  See the documentation
+for an @code{IF_STMT} for more information on the representation used
+for the condition.  The @code{SWITCH_BODY} is the body of the switch
+statement.
+
+@item TRY_BLOCK
+Used to represent a @code{try} block.  The body of the try block is
+given by @code{TRY_STMTS}.  Each of the catch blocks is a @code{HANDLER}
+node.  The first handler is given by @code{TRY_HANDLERS}.  Subsequent
+handlers are obtained by following the @code{TREE_CHAIN} link from one
+handler to the next.  The body of the handler is given by
+@code{HANDLER_BODY}.
+
+If @code{CLEANUP_P} holds of the @code{TRY_BLOCK}, then the
+@code{TRY_HANDLERS} will not be a @code{HANDLER} node.  Instead, it will
+be an expression that should be executed if an exception is thrown in
+the try block.  It must rethrow the exception after executing that code.
+And, if an exception is thrown while the expression is executing,
+@code{terminate} must be called.
+
+@item USING_STMT
+Used to represent a @code{using} directive.  The namespace is given by
+@code{USING_STMT_NAMESPACE}, which will be a NAMESPACE_DECL@.  This node
+is needed inside template functions, to implement using directives
+during instantiation.
+
+@item WHILE_STMT
+
+Used to represent a @code{while} loop.  The @code{WHILE_COND} is the
+termination condition for the loop.  See the documentation for an
+@code{IF_STMT} for more information on the representation used for the
+condition.
+
+The @code{WHILE_BODY} is the body of the loop.
+
+@end table
+
+@c ---------------------------------------------------------------------
+@c Attributes
+@c ---------------------------------------------------------------------
+@node Attributes
+@section Attributes in trees
+@cindex attributes
+
+Attributes, as specified using the @code{__attribute__} keyword, are
+represented internally as a @code{TREE_LIST}.  The @code{TREE_PURPOSE}
+is the name of the attribute, as an @code{IDENTIFIER_NODE}.  The
+@code{TREE_VALUE} is a @code{TREE_LIST} of the arguments of the
+attribute, if any, or @code{NULL_TREE} if there are no arguments; the
+arguments are stored as the @code{TREE_VALUE} of successive entries in
+the list, and may be identifiers or expressions.  The @code{TREE_CHAIN}
+of the attribute is the next attribute in a list of attributes applying
+to the same declaration or type, or @code{NULL_TREE} if there are no
+further attributes in the list.
+
+Attributes may be attached to declarations and to types; these
+attributes may be accessed with the following macros.  All attributes
+are stored in this way, and many also cause other changes to the
+declaration or type or to other internal compiler data structures.
+
+@deftypefn {Tree Macro} tree DECL_ATTRIBUTES (tree @var{decl})
+This macro returns the attributes on the declaration @var{decl}.
+@end deftypefn
+
+@deftypefn {Tree Macro} tree TYPE_ATTRIBUTES (tree @var{type})
+This macro returns the attributes on the type @var{type}.
+@end deftypefn
+
+@c ---------------------------------------------------------------------
+@c Expressions
+@c ---------------------------------------------------------------------
+
+@node Expression trees
+@section Expressions
+@cindex expression
+@findex TREE_OPERAND
+@tindex INTEGER_CST
+@findex TREE_INT_CST_HIGH
+@findex TREE_INT_CST_LOW
+@findex tree_int_cst_lt
+@findex tree_int_cst_equal
+@tindex REAL_CST
+@tindex COMPLEX_CST
+@tindex STRING_CST
+@findex TREE_STRING_LENGTH
+@findex TREE_STRING_POINTER
+@tindex PTRMEM_CST
+@findex PTRMEM_CST_CLASS
+@findex PTRMEM_CST_MEMBER
+@tindex VAR_DECL
+@tindex NEGATE_EXPR
+@tindex BIT_NOT_EXPR
+@tindex TRUTH_NOT_EXPR
+@tindex ADDR_EXPR
+@tindex INDIRECT_REF
+@tindex FIX_TRUNC_EXPR
+@tindex FLOAT_EXPR
+@tindex COMPLEX_EXPR
+@tindex CONJ_EXPR
+@tindex REALPART_EXPR
+@tindex IMAGPART_EXPR
+@tindex NOP_EXPR
+@tindex CONVERT_EXPR
+@tindex THROW_EXPR
+@tindex LSHIFT_EXPR
+@tindex RSHIFT_EXPR
+@tindex BIT_IOR_EXPR
+@tindex BIT_XOR_EXPR
+@tindex BIT_AND_EXPR
+@tindex TRUTH_ANDIF_EXPR
+@tindex TRUTH_ORIF_EXPR
+@tindex TRUTH_AND_EXPR
+@tindex TRUTH_OR_EXPR
+@tindex TRUTH_XOR_EXPR
+@tindex PLUS_EXPR
+@tindex MINUS_EXPR
+@tindex MULT_EXPR
+@tindex TRUNC_DIV_EXPR
+@tindex TRUNC_MOD_EXPR
+@tindex RDIV_EXPR
+@tindex LT_EXPR
+@tindex LE_EXPR
+@tindex GT_EXPR
+@tindex GE_EXPR
+@tindex EQ_EXPR
+@tindex NE_EXPR
+@tindex INIT_EXPR
+@tindex MODIFY_EXPR
+@tindex COMPONENT_REF
+@tindex COMPOUND_EXPR
+@tindex COND_EXPR
+@tindex CALL_EXPR
+@tindex CONSTRUCTOR
+@tindex COMPOUND_LITERAL_EXPR
+@tindex STMT_EXPR
+@tindex BIND_EXPR
+@tindex LOOP_EXPR
+@tindex EXIT_EXPR
+@tindex CLEANUP_POINT_EXPR
+@tindex ARRAY_REF
+@tindex VTABLE_REF
+
+The internal representation for expressions is for the most part quite
+straightforward.  However, there are a few facts that one must bear in
+mind.  In particular, the expression ``tree'' is actually a directed
+acyclic graph.  (For example there may be many references to the integer
+constant zero throughout the source program; many of these will be
+represented by the same expression node.)  You should not rely on
+certain kinds of node being shared, nor should rely on certain kinds of
+nodes being unshared.
+
+The following macros can be used with all expression nodes:
+
+@ftable @code
+@item TREE_TYPE
+Returns the type of the expression.  This value may not be precisely the
+same type that would be given the expression in the original program.
+@end ftable
+
+In what follows, some nodes that one might expect to always have type
+@code{bool} are documented to have either integral or boolean type.  At
+some point in the future, the C front end may also make use of this same
+intermediate representation, and at this point these nodes will
+certainly have integral type.  The previous sentence is not meant to
+imply that the C++ front end does not or will not give these nodes
+integral type.
+
+Below, we list the various kinds of expression nodes.  Except where
+noted otherwise, the operands to an expression are accessed using the
+@code{TREE_OPERAND} macro.  For example, to access the first operand to
+a binary plus expression @code{expr}, use:
+
+@example
+TREE_OPERAND (expr, 0)
+@end example
+@noindent
+As this example indicates, the operands are zero-indexed.
+
+The table below begins with constants, moves on to unary expressions,
+then proceeds to binary expressions, and concludes with various other
+kinds of expressions:
+
+@table @code
+@item INTEGER_CST
+These nodes represent integer constants.  Note that the type of these
+constants is obtained with @code{TREE_TYPE}; they are not always of type
+@code{int}.  In particular, @code{char} constants are represented with
+@code{INTEGER_CST} nodes.  The value of the integer constant @code{e} is
+given by @example
+((TREE_INT_CST_HIGH (e) << HOST_BITS_PER_WIDE_INT)
++ TREE_INST_CST_LOW (e))
+@end example
+@noindent
+HOST_BITS_PER_WIDE_INT is at least thirty-two on all platforms.  Both
+@code{TREE_INT_CST_HIGH} and @code{TREE_INT_CST_LOW} return a
+@code{HOST_WIDE_INT}.  The value of an @code{INTEGER_CST} is interpreted
+as a signed or unsigned quantity depending on the type of the constant.
+In general, the expression given above will overflow, so it should not
+be used to calculate the value of the constant.
+
+The variable @code{integer_zero_node} is an integer constant with value
+zero.  Similarly, @code{integer_one_node} is an integer constant with
+value one.  The @code{size_zero_node} and @code{size_one_node} variables
+are analogous, but have type @code{size_t} rather than @code{int}.
+
+The function @code{tree_int_cst_lt} is a predicate which holds if its
+first argument is less than its second.  Both constants are assumed to
+have the same signedness (i.e., either both should be signed or both
+should be unsigned.)  The full width of the constant is used when doing
+the comparison; the usual rules about promotions and conversions are
+ignored.  Similarly, @code{tree_int_cst_equal} holds if the two
+constants are equal.  The @code{tree_int_cst_sgn} function returns the
+sign of a constant.  The value is @code{1}, @code{0}, or @code{-1}
+according on whether the constant is greater than, equal to, or less
+than zero.  Again, the signedness of the constant's type is taken into
+account; an unsigned constant is never less than zero, no matter what
+its bit-pattern.
+
+@item REAL_CST
+
+FIXME: Talk about how to obtain representations of this constant, do
+comparisons, and so forth.
+
+@item COMPLEX_CST
+These nodes are used to represent complex number constants, that is a
+@code{__complex__} whose parts are constant nodes.  The
+@code{TREE_REALPART} and @code{TREE_IMAGPART} return the real and the
+imaginary parts respectively.
+
+@item STRING_CST
+These nodes represent string-constants.  The @code{TREE_STRING_LENGTH}
+returns the length of the string, as an @code{int}.  The
+@code{TREE_STRING_POINTER} is a @code{char*} containing the string
+itself.  The string may not be @code{NUL}-terminated, and it may contain
+embedded @code{NUL} characters.  Therefore, the
+@code{TREE_STRING_LENGTH} includes the trailing @code{NUL} if it is
+present.
+
+For wide string constants, the @code{TREE_STRING_LENGTH} is the number
+of bytes in the string, and the @code{TREE_STRING_POINTER}
+points to an array of the bytes of the string, as represented on the
+target system (that is, as integers in the target endianness).  Wide and
+non-wide string constants are distinguished only by the @code{TREE_TYPE}
+of the @code{STRING_CST}.
+
+FIXME: The formats of string constants are not well-defined when the
+target system bytes are not the same width as host system bytes.
+
+@item PTRMEM_CST
+These nodes are used to represent pointer-to-member constants.  The
+@code{PTRMEM_CST_CLASS} is the class type (either a @code{RECORD_TYPE}
+or @code{UNION_TYPE} within which the pointer points), and the
+@code{PTRMEM_CST_MEMBER} is the declaration for the pointed to object.
+Note that the @code{DECL_CONTEXT} for the @code{PTRMEM_CST_MEMBER} is in
+general different from the @code{PTRMEM_CST_CLASS}.  For example,
+given:
+@example
+struct B @{ int i; @};
+struct D : public B @{@};
+int D::*dp = &D::i;
+@end example
+@noindent
+The @code{PTRMEM_CST_CLASS} for @code{&D::i} is @code{D}, even though
+the @code{DECL_CONTEXT} for the @code{PTRMEM_CST_MEMBER} is @code{B},
+since @code{B::i} is a member of @code{B}, not @code{D}.
+
+@item VAR_DECL
+
+These nodes represent variables, including static data members.  For
+more information, @pxref{Declarations}.
+
+@item NEGATE_EXPR
+These nodes represent unary negation of the single operand, for both
+integer and floating-point types.  The type of negation can be
+determined by looking at the type of the expression.
+
+@item BIT_NOT_EXPR
+These nodes represent bitwise complement, and will always have integral
+type.  The only operand is the value to be complemented.
+
+@item TRUTH_NOT_EXPR
+These nodes represent logical negation, and will always have integral
+(or boolean) type.  The operand is the value being negated.
+
+@item PREDECREMENT_EXPR
+@itemx PREINCREMENT_EXPR
+@itemx POSTDECREMENT_EXPR
+@itemx POSTINCREMENT_EXPR
+These nodes represent increment and decrement expressions.  The value of
+the single operand is computed, and the operand incremented or
+decremented.  In the case of @code{PREDECREMENT_EXPR} and
+@code{PREINCREMENT_EXPR}, the value of the expression is the value
+resulting after the increment or decrement; in the case of
+@code{POSTDECREMENT_EXPR} and @code{POSTINCREMENT_EXPR} is the value
+before the increment or decrement occurs.  The type of the operand, like
+that of the result, will be either integral, boolean, or floating-point.
+
+@item ADDR_EXPR
+These nodes are used to represent the address of an object.  (These
+expressions will always have pointer or reference type.)  The operand may
+be another expression, or it may be a declaration.
+
+As an extension, GCC allows users to take the address of a label.  In
+this case, the operand of the @code{ADDR_EXPR} will be a
+@code{LABEL_DECL}.  The type of such an expression is @code{void*}.
+
+If the object addressed is not an lvalue, a temporary is created, and
+the address of the temporary is used.
+
+@item INDIRECT_REF
+These nodes are used to represent the object pointed to by a pointer.
+The operand is the pointer being dereferenced; it will always have
+pointer or reference type.
+
+@item FIX_TRUNC_EXPR
+These nodes represent conversion of a floating-point value to an
+integer.  The single operand will have a floating-point type, while the
+the complete expression will have an integral (or boolean) type.  The
+operand is rounded towards zero.
+
+@item FLOAT_EXPR
+These nodes represent conversion of an integral (or boolean) value to a
+floating-point value.  The single operand will have integral type, while
+the complete expression will have a floating-point type.
+
+FIXME: How is the operand supposed to be rounded?  Is this dependent on
+@option{-mieee}?
+
+@item COMPLEX_EXPR
+These nodes are used to represent complex numbers constructed from two
+expressions of the same (integer or real) type.  The first operand is the
+real part and the second operand is the imaginary part.
+
+@item CONJ_EXPR
+These nodes represent the conjugate of their operand.
+
+@item REALPART_EXPR
+@item IMAGPART_EXPR
+These nodes represent respectively the real and the imaginary parts
+of complex numbers (their sole argument).
+
+@item NON_LVALUE_EXPR
+These nodes indicate that their one and only operand is not an lvalue.
+A back end can treat these identically to the single operand.
+
+@item NOP_EXPR
+These nodes are used to represent conversions that do not require any
+code-generation.  For example, conversion of a @code{char*} to an
+@code{int*} does not require any code be generated; such a conversion is
+represented by a @code{NOP_EXPR}.  The single operand is the expression
+to be converted.  The conversion from a pointer to a reference is also
+represented with a @code{NOP_EXPR}.
+
+@item CONVERT_EXPR
+These nodes are similar to @code{NOP_EXPR}s, but are used in those
+situations where code may need to be generated.  For example, if an
+@code{int*} is converted to an @code{int} code may need to be generated
+on some platforms.  These nodes are never used for C++-specific
+conversions, like conversions between pointers to different classes in
+an inheritance hierarchy.  Any adjustments that need to be made in such
+cases are always indicated explicitly.  Similarly, a user-defined
+conversion is never represented by a @code{CONVERT_EXPR}; instead, the
+function calls are made explicit.
+
+@item THROW_EXPR
+These nodes represent @code{throw} expressions.  The single operand is
+an expression for the code that should be executed to throw the
+exception.  However, there is one implicit action not represented in
+that expression; namely the call to @code{__throw}.  This function takes
+no arguments.  If @code{setjmp}/@code{longjmp} exceptions are used, the
+function @code{__sjthrow} is called instead.  The normal GCC back end
+uses the function @code{emit_throw} to generate this code; you can
+examine this function to see what needs to be done.
+
+@item LSHIFT_EXPR
+@itemx RSHIFT_EXPR
+These nodes represent left and right shifts, respectively.  The first
+operand is the value to shift; it will always be of integral type.  The
+second operand is an expression for the number of bits by which to
+shift.  Right shift should be treated as arithmetic, i.e., the
+high-order bits should be zero-filled when the expression has unsigned
+type and filled with the sign bit when the expression has signed type.
+Note that the result is undefined if the second operand is larger
+than the first operand's type size.
+
+
+@item BIT_IOR_EXPR
+@itemx BIT_XOR_EXPR
+@itemx BIT_AND_EXPR
+These nodes represent bitwise inclusive or, bitwise exclusive or, and
+bitwise and, respectively.  Both operands will always have integral
+type.
+
+@item TRUTH_ANDIF_EXPR
+@itemx TRUTH_ORIF_EXPR
+These nodes represent logical and and logical or, respectively.  These
+operators are not strict; i.e., the second operand is evaluated only if
+the value of the expression is not determined by evaluation of the first
+operand.  The type of the operands, and the result type, is always of
+boolean or integral type.
+
+@item TRUTH_AND_EXPR
+@itemx TRUTH_OR_EXPR
+@itemx TRUTH_XOR_EXPR
+These nodes represent logical and, logical or, and logical exclusive or.
+They are strict; both arguments are always evaluated.  There are no
+corresponding operators in C or C++, but the front end will sometimes
+generate these expressions anyhow, if it can tell that strictness does
+not matter.
+
+@itemx PLUS_EXPR
+@itemx MINUS_EXPR
+@itemx MULT_EXPR
+@itemx TRUNC_DIV_EXPR
+@itemx TRUNC_MOD_EXPR
+@itemx RDIV_EXPR
+These nodes represent various binary arithmetic operations.
+Respectively, these operations are addition, subtraction (of the second
+operand from the first), multiplication, integer division, integer
+remainder, and floating-point division.  The operands to the first three
+of these may have either integral or floating type, but there will never
+be case in which one operand is of floating type and the other is of
+integral type.
+
+The result of a @code{TRUNC_DIV_EXPR} is always rounded towards zero.
+The @code{TRUNC_MOD_EXPR} of two operands @code{a} and @code{b} is
+always @code{a - a/b} where the division is as if computed by a
+@code{TRUNC_DIV_EXPR}.
+
+@item ARRAY_REF
+These nodes represent array accesses.  The first operand is the array;
+the second is the index.  To calculate the address of the memory
+accessed, you must scale the index by the size of the type of the array
+elements.  The type of these expressions must be the type of a component of
+the array.
+
+@item ARRAY_RANGE_REF
+These nodes represent access to a range (or ``slice'') of an array.  The
+operands are the same as that for @code{ARRAY_REF} and have the same
+meanings.  The type of these expressions must be an array whose component
+type is the same as that of the first operand.  The range of that array
+type determines the amount of data these expressions access.
+
+@item EXACT_DIV_EXPR
+Document.
+
+@item LT_EXPR
+@itemx LE_EXPR
+@itemx GT_EXPR
+@itemx GE_EXPR
+@itemx EQ_EXPR
+@itemx NE_EXPR
+
+These nodes represent the less than, less than or equal to, greater
+than, greater than or equal to, equal, and not equal comparison
+operators.  The first and second operand with either be both of integral
+type or both of floating type.  The result type of these expressions
+will always be of integral or boolean type.
+
+@item MODIFY_EXPR
+These nodes represent assignment.  The left-hand side is the first
+operand; the right-hand side is the second operand.  The left-hand side
+will be a @code{VAR_DECL}, @code{INDIRECT_REF}, @code{COMPONENT_REF}, or
+other lvalue.
+
+These nodes are used to represent not only assignment with @samp{=} but
+also compound assignments (like @samp{+=}), by reduction to @samp{=}
+assignment.  In other words, the representation for @samp{i += 3} looks
+just like that for @samp{i = i + 3}.
+
+@item INIT_EXPR
+These nodes are just like @code{MODIFY_EXPR}, but are used only when a
+variable is initialized, rather than assigned to subsequently.
+
+@item COMPONENT_REF
+These nodes represent non-static data member accesses.  The first
+operand is the object (rather than a pointer to it); the second operand
+is the @code{FIELD_DECL} for the data member.
+
+@item COMPOUND_EXPR
+These nodes represent comma-expressions.  The first operand is an
+expression whose value is computed and thrown away prior to the
+evaluation of the second operand.  The value of the entire expression is
+the value of the second operand.
+
+@item COND_EXPR
+These nodes represent @code{?:} expressions.  The first operand
+is of boolean or integral type.  If it evaluates to a nonzero value,
+the second operand should be evaluated, and returned as the value of the
+expression.  Otherwise, the third operand is evaluated, and returned as
+the value of the expression.  As a GNU extension, the middle operand of
+the @code{?:} operator may be omitted in the source, like this:
+
+@example
+x ? : 3
+@end example
+@noindent
+which is equivalent to
+
+@example
+x ? x : 3
+@end example
+
+@noindent
+assuming that @code{x} is an expression without side-effects.  However,
+in the case that the first operation causes side effects, the
+side-effects occur only once.  Consumers of the internal representation
+do not need to worry about this oddity; the second operand will be
+always be present in the internal representation.
+
+@item CALL_EXPR
+These nodes are used to represent calls to functions, including
+non-static member functions.  The first operand is a pointer to the
+function to call; it is always an expression whose type is a
+@code{POINTER_TYPE}.  The second argument is a @code{TREE_LIST}.  The
+arguments to the call appear left-to-right in the list.  The
+@code{TREE_VALUE} of each list node contains the expression
+corresponding to that argument.  (The value of @code{TREE_PURPOSE} for
+these nodes is unspecified, and should be ignored.)  For non-static
+member functions, there will be an operand corresponding to the
+@code{this} pointer.  There will always be expressions corresponding to
+all of the arguments, even if the function is declared with default
+arguments and some arguments are not explicitly provided at the call
+sites.
+
+@item STMT_EXPR
+These nodes are used to represent GCC's statement-expression extension.
+The statement-expression extension allows code like this:
+@example
+int f() @{ return (@{ int j; j = 3; j + 7; @}); @}
+@end example
+In other words, an sequence of statements may occur where a single
+expression would normally appear.  The @code{STMT_EXPR} node represents
+such an expression.  The @code{STMT_EXPR_STMT} gives the statement
+contained in the expression; this is always a @code{COMPOUND_STMT}.  The
+value of the expression is the value of the last sub-statement in the
+@code{COMPOUND_STMT}.  More precisely, the value is the value computed
+by the last @code{EXPR_STMT} in the outermost scope of the
+@code{COMPOUND_STMT}.  For example, in:
+@example
+(@{ 3; @})
+@end example
+the value is @code{3} while in:
+@example
+(@{ if (x) @{ 3; @} @})
+@end example
+(represented by a nested @code{COMPOUND_STMT}), there is no value.  If
+the @code{STMT_EXPR} does not yield a value, it's type will be
+@code{void}.
+
+@item BIND_EXPR
+These nodes represent local blocks.  The first operand is a list of
+temporary variables, connected via their @code{TREE_CHAIN} field.  These
+will never require cleanups.  The scope of these variables is just the
+body of the @code{BIND_EXPR}.  The body of the @code{BIND_EXPR} is the
+second operand.
+
+@item LOOP_EXPR
+These nodes represent ``infinite'' loops.  The @code{LOOP_EXPR_BODY}
+represents the body of the loop.  It should be executed forever, unless
+an @code{EXIT_EXPR} is encountered.
+
+@item EXIT_EXPR
+These nodes represent conditional exits from the nearest enclosing
+@code{LOOP_EXPR}.  The single operand is the condition; if it is
+nonzero, then the loop should be exited.  An @code{EXIT_EXPR} will only
+appear within a @code{LOOP_EXPR}.
+
+@item CLEANUP_POINT_EXPR
+These nodes represent full-expressions.  The single operand is an
+expression to evaluate.  Any destructor calls engendered by the creation
+of temporaries during the evaluation of that expression should be
+performed immediately after the expression is evaluated.
+
+@item CONSTRUCTOR
+These nodes represent the brace-enclosed initializers for a structure or
+array.  The first operand is reserved for use by the back end.  The
+second operand is a @code{TREE_LIST}.  If the @code{TREE_TYPE} of the
+@code{CONSTRUCTOR} is a @code{RECORD_TYPE} or @code{UNION_TYPE}, then
+the @code{TREE_PURPOSE} of each node in the @code{TREE_LIST} will be a
+@code{FIELD_DECL} and the @code{TREE_VALUE} of each node will be the
+expression used to initialize that field.  You should not depend on the
+fields appearing in any particular order, nor should you assume that all
+fields will be represented.  Unrepresented fields may be assigned any
+value.
+
+If the @code{TREE_TYPE} of the @code{CONSTRUCTOR} is an
+@code{ARRAY_TYPE}, then the @code{TREE_PURPOSE} of each element in the
+@code{TREE_LIST} will be an @code{INTEGER_CST}.  This constant indicates
+which element of the array (indexed from zero) is being assigned to;
+again, the @code{TREE_VALUE} is the corresponding initializer.  If the
+@code{TREE_PURPOSE} is @code{NULL_TREE}, then the initializer is for the
+next available array element.
+
+Conceptually, before any initialization is done, the entire area of
+storage is initialized to zero.
+
+@item COMPOUND_LITERAL_EXPR
+@findex COMPOUND_LITERAL_EXPR_DECL_STMT
+@findex COMPOUND_LITERAL_EXPR_DECL
+These nodes represent ISO C99 compound literals.  The
+@code{COMPOUND_LITERAL_EXPR_DECL_STMT} is a @code{DECL_STMT}
+containing an anonymous @code{VAR_DECL} for
+the unnamed object represented by the compound literal; the
+@code{DECL_INITIAL} of that @code{VAR_DECL} is a @code{CONSTRUCTOR}
+representing the brace-enclosed list of initializers in the compound
+literal.  That anonymous @code{VAR_DECL} can also be accessed directly
+by the @code{COMPOUND_LITERAL_EXPR_DECL} macro.
+
+@item SAVE_EXPR
+
+A @code{SAVE_EXPR} represents an expression (possibly involving
+side-effects) that is used more than once.  The side-effects should
+occur only the first time the expression is evaluated.  Subsequent uses
+should just reuse the computed value.  The first operand to the
+@code{SAVE_EXPR} is the expression to evaluate.  The side-effects should
+be executed where the @code{SAVE_EXPR} is first encountered in a
+depth-first preorder traversal of the expression tree.
+
+@item TARGET_EXPR
+A @code{TARGET_EXPR} represents a temporary object.  The first operand
+is a @code{VAR_DECL} for the temporary variable.  The second operand is
+the initializer for the temporary.  The initializer is evaluated, and
+copied (bitwise) into the temporary.
+
+Often, a @code{TARGET_EXPR} occurs on the right-hand side of an
+assignment, or as the second operand to a comma-expression which is
+itself the right-hand side of an assignment, etc.  In this case, we say
+that the @code{TARGET_EXPR} is ``normal''; otherwise, we say it is
+``orphaned''.  For a normal @code{TARGET_EXPR} the temporary variable
+should be treated as an alias for the left-hand side of the assignment,
+rather than as a new temporary variable.
+
+The third operand to the @code{TARGET_EXPR}, if present, is a
+cleanup-expression (i.e., destructor call) for the temporary.  If this
+expression is orphaned, then this expression must be executed when the
+statement containing this expression is complete.  These cleanups must
+always be executed in the order opposite to that in which they were
+encountered.  Note that if a temporary is created on one branch of a
+conditional operator (i.e., in the second or third operand to a
+@code{COND_EXPR}), the cleanup must be run only if that branch is
+actually executed.
+
+See @code{STMT_IS_FULL_EXPR_P} for more information about running these
+cleanups.
+
+@item AGGR_INIT_EXPR
+An @code{AGGR_INIT_EXPR} represents the initialization as the return
+value of a function call, or as the result of a constructor.  An
+@code{AGGR_INIT_EXPR} will only appear as the second operand of a
+@code{TARGET_EXPR}.  The first operand to the @code{AGGR_INIT_EXPR} is
+the address of a function to call, just as in a @code{CALL_EXPR}.  The
+second operand are the arguments to pass that function, as a
+@code{TREE_LIST}, again in a manner similar to that of a
+@code{CALL_EXPR}.  The value of the expression is that returned by the
+function.
+
+If @code{AGGR_INIT_VIA_CTOR_P} holds of the @code{AGGR_INIT_EXPR}, then
+the initialization is via a constructor call.  The address of the third
+operand of the @code{AGGR_INIT_EXPR}, which is always a @code{VAR_DECL},
+is taken, and this value replaces the first argument in the argument
+list.  In this case, the value of the expression is the @code{VAR_DECL}
+given by the third operand to the @code{AGGR_INIT_EXPR}; constructors do
+not return a value.
+
+@item VTABLE_REF
+A @code{VTABLE_REF} indicates that the interior expression computes
+a value that is a vtable entry.  It is used with @option{-fvtable-gc}
+to track the reference through to front end to the middle end, at
+which point we transform this to a @code{REG_VTABLE_REF} note, which
+survives the balance of code generation.
+
+The first operand is the expression that computes the vtable reference.
+The second operand is the @code{VAR_DECL} of the vtable.  The third
+operand is an @code{INTEGER_CST} of the byte offset into the vtable.
+
+@end table
diff --git a/contrib/gcc/doc/collect2.texi b/contrib/gcc/doc/collect2.texi
new file mode 100644
index 0000000..2cd1d3c
--- /dev/null
+++ b/contrib/gcc/doc/collect2.texi
@@ -0,0 +1,85 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Collect2
+@chapter @code{collect2}
+
+GNU CC uses a utility called @code{collect2} on nearly all systems to arrange
+to call various initialization functions at start time.
+
+The program @code{collect2} works by linking the program once and
+looking through the linker output file for symbols with particular names
+indicating they are constructor functions.  If it finds any, it
+creates a new temporary @samp{.c} file containing a table of them,
+compiles it, and links the program a second time including that file.
+
+@findex __main
+@cindex constructors, automatic calls
+The actual calls to the constructors are carried out by a subroutine
+called @code{__main}, which is called (automatically) at the beginning
+of the body of @code{main} (provided @code{main} was compiled with GNU
+CC)@.  Calling @code{__main} is necessary, even when compiling C code, to
+allow linking C and C++ object code together.  (If you use
+@option{-nostdlib}, you get an unresolved reference to @code{__main},
+since it's defined in the standard GCC library.  Include @option{-lgcc} at
+the end of your compiler command line to resolve this reference.)
+
+The program @code{collect2} is installed as @code{ld} in the directory
+where the passes of the compiler are installed.  When @code{collect2}
+needs to find the @emph{real} @code{ld}, it tries the following file
+names:
+
+@itemize @bullet
+@item
+@file{real-ld} in the directories listed in the compiler's search
+directories.
+
+@item
+@file{real-ld} in the directories listed in the environment variable
+@code{PATH}.
+
+@item
+The file specified in the @code{REAL_LD_FILE_NAME} configuration macro,
+if specified.
+
+@item
+@file{ld} in the compiler's search directories, except that
+@code{collect2} will not execute itself recursively.
+
+@item
+@file{ld} in @code{PATH}.
+@end itemize
+
+``The compiler's search directories'' means all the directories where
+@code{gcc} searches for passes of the compiler.  This includes
+directories that you specify with @option{-B}.
+
+Cross-compilers search a little differently:
+
+@itemize @bullet
+@item
+@file{real-ld} in the compiler's search directories.
+
+@item
+@file{@var{target}-real-ld} in @code{PATH}.
+
+@item
+The file specified in the @code{REAL_LD_FILE_NAME} configuration macro,
+if specified.
+
+@item
+@file{ld} in the compiler's search directories.
+
+@item
+@file{@var{target}-ld} in @code{PATH}.
+@end itemize
+
+@code{collect2} explicitly avoids running @code{ld} using the file name
+under which @code{collect2} itself was invoked.  In fact, it remembers
+up a list of such names---in case one copy of @code{collect2} finds
+another copy (or version) of @code{collect2} installed as @code{ld} in a
+second place in the search path.
+
+@code{collect2} searches for the utilities @code{nm} and @code{strip}
+using the same algorithm as above for @code{ld}.
diff --git a/contrib/gcc/doc/configfiles.texi b/contrib/gcc/doc/configfiles.texi
new file mode 100644
index 0000000..c6c60bb
--- /dev/null
+++ b/contrib/gcc/doc/configfiles.texi
@@ -0,0 +1,74 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+@c 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Configuration Files
+@subsubsection Files Created by @code{configure}
+
+Here we spell out what files will be set up by @file{configure} in the
+@file{gcc} directory.  Some other files are created as temporary files
+in the configuration process, and are not used in the subsequent
+build; these are not documented.
+
+@itemize @bullet
+@item
+@file{Makefile} is constructed from @file{Makefile.in}, together with
+the host and target fragments (@pxref{Fragments, , Makefile
+Fragments}) @file{t-@var{target}} and @file{x-@var{host}} from
+@file{config}, if any, and language Makefile fragments
+@file{@var{language}/Make-lang.in}.
+@item
+@file{auto-host.h} contains information about the host machine
+determined by @file{configure}.  If the host machine is different from
+the build machine, then @file{auto-build.h} is also created,
+containing such information about the build machine.
+@item
+@file{config.status} is a script that may be run to recreate the
+current configuration.
+@item
+@file{configargs.h} is a header containing details of the arguments
+passed to @file{configure} to configure GCC, and of the thread model
+used.
+@item
+@file{cstamp-h} is used as a timestamp.
+@item
+@file{fixinc/Makefile} is constructed from @file{fixinc/Makefile.in}.
+@item
+@file{gccbug}, a script for reporting bugs in GCC, is constructed from
+@file{gccbug.in}.
+@item
+@file{intl/Makefile} is constructed from @file{intl/Makefile.in}.
+@item
+@file{mklibgcc}, a shell script to create a Makefile to build libgcc,
+is constructed from @file{mklibgcc.in}.
+@item
+If a language @file{config-lang.in} file (@pxref{Front End Config, ,
+The Front End @file{config-lang.in} File}) sets @code{outputs}, then
+the files listed in @code{outputs} there are also generated.
+@end itemize
+
+The following configuration headers are created from the Makefile,
+using @file{mkconfig.sh}, rather than directly by @file{configure}.
+@file{config.h}, @file{hconfig.h} and @file{tconfig.h} all contain the
+@file{xm-@var{machine}.h} header, if any, appropriate to the host,
+build and target machines respectively, the configuration headers for
+the target, and some definitions; for the host and build machines,
+these include the autoconfigured headers generated by
+@file{configure}.  The other configuration headers are determined by
+@file{config.gcc}.  They also contain the typedefs for @code{rtx},
+@code{rtvec} and @code{tree}.
+
+@itemize @bullet
+@item
+@file{config.h}, for use in programs that run on the host machine.
+@item
+@file{hconfig.h}, for use in programs that run on the build machine.
+@item
+@file{tconfig.h}, for use in programs and libraries for the target
+machine.
+@item
+@file{tm_p.h}, which includes the header @file{@var{machine}-protos.h}
+that contains prototypes for functions in the target @file{.c} file.
+FIXME: why is such a separate header necessary?
+@end itemize
diff --git a/contrib/gcc/doc/configterms.texi b/contrib/gcc/doc/configterms.texi
new file mode 100644
index 0000000..39b3152
--- /dev/null
+++ b/contrib/gcc/doc/configterms.texi
@@ -0,0 +1,61 @@
+@c Copyright (C) 2001, 2002 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Configure Terms
+@section Configure Terms and History
+@cindex configure terms
+@cindex canadian
+
+The configure and build process has a long and colorful history, and can
+be confusing to anyone who doesn't know why things are the way they are.
+While there are other documents which describe the configuration process
+in detail, here are a few things that everyone working on GCC should
+know.
+
+There are three system names that the build knows about: the machine you
+are building on (@dfn{build}), the machine that you are building for
+(@dfn{host}), and the machine that GCC will produce code for
+(@dfn{target}).  When you configure GCC, you specify these with
+@option{--build=}, @option{--host=}, and @option{--target=}.
+
+Specifying the host without specifying the build should be avoided, as
+@command{configure} may (and once did) assume that the host you specify
+is also the build, which may not be true.
+
+If build, host, and target are all the same, this is called a
+@dfn{native}.  If build and host are the same but target is different,
+this is called a @dfn{cross}.  If build, host, and target are all
+different this is called a @dfn{canadian} (for obscure reasons dealing
+with Canada's political party and the background of the person working
+on the build at that time).  If host and target are the same, but build
+is different, you are using a cross-compiler to build a native for a
+different system.  Some people call this a @dfn{host-x-host},
+@dfn{crossed native}, or @dfn{cross-built native}.  If build and target
+are the same, but host is different, you are using a cross compiler to
+build a cross compiler that produces code for the machine you're
+building on.  This is rare, so there is no common way of describing it
+(although I propose calling it a @dfn{crossback}).
+
+If build and host are the same, the GCC you are building will also be
+used to build the target libraries (like @code{libstdc++}).  If build and host
+are different, you must have already build and installed a cross
+compiler that will be used to build the target libraries (if you
+configured with @option{--target=foo-bar}, this compiler will be called
+@command{foo-bar-gcc}).
+
+In the case of target libraries, the machine you're building for is the
+machine you specified with @option{--target}.  So, build is the machine
+you're building on (no change there), host is the machine you're
+building for (the target libraries are built for the target, so host is
+the target you specified), and target doesn't apply (because you're not
+building a compiler, you're building libraries).  The configure/make
+process will adjust these variables as needed.  It also sets
+@code{$with_cross_host} to the original @option{--host} value in case you
+need it.
+
+The @code{libiberty} support library is built up to three times: once
+for the host, once for the target (even if they are the same), and once
+for the build if build and host are different.  This allows it to be
+used by all programs which are generated in the course of the build
+process.
diff --git a/contrib/gcc/doc/contrib.texi b/contrib/gcc/doc/contrib.texi
new file mode 100644
index 0000000..966d3ec
--- /dev/null
+++ b/contrib/gcc/doc/contrib.texi
@@ -0,0 +1,712 @@
+@c Copyright (C) 1988,1989,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001
+@c Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Contributors
+@unnumbered Contributors to GCC
+@cindex contributors
+
+The GCC project would like to thank its many contributors.  Without them the
+project would not have been nearly as successful as it has been.  Any omissions
+in this list are accidental.  Feel free to contact
+@email{law@@redhat.com} if you have been left out
+or some of your contributions are not listed.  Please keep this list in
+alphabetical order.
+
+Some projects operating under the GCC project maintain their own list
+of contributors, such as
+@uref{http://gcc.gnu.org/libstdc++/,the C++ library}.
+
+@itemize @bullet
+
+@item
+Analog Devices helped implement the support for complex data types
+and iterators.
+
+@item
+James van Artsdalen wrote the code that makes efficient use of
+the Intel 80387 register stack.
+
+@item
+Alasdair Baird for various bugfixes.
+
+@item
+Gerald Baumgartner added the signature extension to the C++ front end.
+
+@item
+Neil Booth for various work on cpplib.
+
+@item
+Per Bothner for his direction via the steering committee and various
+improvements to our infrastructure for supporting new languages.  Chill
+and Java front end implementations.  Initial implementations of
+cpplib, fix-header, config.guess, libio, and past C++ library
+(libg++) maintainer.
+
+@item
+Devon Bowen helped port GCC to the Tahoe.
+
+@item
+Don Bowman for mips-vxworks contributions.
+
+@item
+Dave Brolley for work on cpplib and Chill.
+
+@item
+Robert Brown implemented the support for Encore 32000 systems.
+
+@item
+Christian Bruel for improvements to local store elimination.
+
+@item
+Herman A.J. ten Brugge for various fixes.
+
+@item
+Joe Buck for his direction via the steering committee.
+
+@item
+Craig Burley for leadership of the Fortran effort.
+
+@item
+John Carr for his alias work, SPARC hacking, infrastructure improvements,
+previous contributions to the steering committee, loop optimizations, etc.
+
+@item
+Steve Chamberlain wrote the support for the Hitachi SH and H8 processors
+and the PicoJava processor.
+
+@item
+Scott Christley for his ObjC contributions.
+
+@item
+Branko Cibej for more warning contributions.
+
+@item
+Nick Clifton for arm, mcore, fr30, v850, m32r work, @option{--help}, and other random
+hacking.
+
+@item
+Ralf Corsepius for SH testing and minor bugfixing.
+
+@item
+Stan Cox for care and feeding of the x86 port and lots of behind
+the scenes hacking.
+
+@item
+Alex Crain provided changes for the 3b1.
+
+@item
+Ian Dall for major improvements to the NS32k port.
+
+@item
+Dario Dariol contributed the four varieties of sample programs
+that print a copy of their source.
+
+@item
+Ulrich Drepper for his work on the C++ runtime libraries, glibc,
+ testing of GCC using glibc, ISO C99 support, CFG dumping support, etc.
+
+@item
+Richard Earnshaw for his ongoing work with the ARM@.
+
+@item
+David Edelsohn for his direction via the steering committee,
+ongoing work with the RS6000/PowerPC port, and help cleaning up Haifa
+loop changes.
+
+@item
+Paul Eggert for random hacking all over GCC@.
+
+@item
+Mark Elbrecht for various DJGPP improvements.
+
+@item
+Ben Elliston for his work to move the Objective-C runtime into its
+own subdirectory and for his work on autoconf.
+
+@item
+Marc Espie for OpenBSD support.
+
+@item
+Doug Evans for much of the global optimization framework, arc, m32r,
+and SPARC work.
+
+@item
+Fred Fish for BeOS support and Ada fixes.
+
+@item
+Peter Gerwinski for various bugfixes and the Pascal front end.
+
+@item
+Kaveh Ghazi for his direction via the steering committee and
+amazing work to make @samp{-W -Wall} useful.
+
+@item
+Judy Goldberg for c++ contributions.
+
+@item
+Torbjorn Granlund for various fixes and the c-torture testsuite,
+multiply- and divide-by-constant optimization, improved long long
+support, improved leaf function register allocation, and his direction
+via the steering committee.
+
+@item
+Anthony Green for his @option{-Os} contributions and Java front end work.
+
+@item
+Michael K. Gschwind contributed the port to the PDP-11.
+
+@item
+Ron Guilmette implemented the @command{protoize} and @command{unprotoize}
+tools, the support for Dwarf symbolic debugging information, and much of
+the support for System V Release 4.  He has also worked heavily on the
+Intel 386 and 860 support.
+
+@item
+Bruno Haible for improvements in the runtime overhead for EH, new
+warnings and assorted bugfixes.
+
+@item
+Andrew Haley for his Java work.
+
+@item
+Chris Hanson assisted in making GCC work on HP-UX for the 9000 series 300.
+
+@item
+Michael Hayes for various thankless work he's done trying to get
+the c30/c40 ports functional.  Lots of loop and unroll improvements and
+fixes.
+
+@item
+Kate Hedstrom for staking the g77 folks with an initial testsuite.
+
+@item
+Richard Henderson for his ongoing SPARC and alpha work, loop opts, and
+generally fixing lots of old problems we've ignored for years, flow
+rewrite and lots of stuff I've forgotten.
+
+@item
+Nobuyuki Hikichi of Software Research Associates, Tokyo, contributed
+the support for the Sony NEWS machine.
+
+@item
+Manfred Hollstein for his ongoing work to keep the m88k alive, lots
+of testing an bugfixing, particularly of our configury code.
+
+@item
+Steve Holmgren for MachTen patches.
+
+@item
+Jan Hubicka for his x86 port improvements.
+
+@item
+Christian Iseli for various bugfixes.
+
+@item
+Kamil Iskra for general m68k hacking.
+
+@item
+Lee Iverson for random fixes and mips testing.
+
+@item
+Andreas Jaeger for various fixes to the MIPS port
+
+@item
+Jakub Jelinek for his SPARC work and sibling call optimizations.
+
+@item
+J. Kean Johnston for OpenServer support.
+
+@item
+Klaus Kaempf for his ongoing work to make alpha-vms a viable target.
+
+@item
+David Kashtan of SRI adapted GCC to VMS@.
+
+@item
+Geoffrey Keating for his ongoing work to make the PPC work for Linux.
+
+@item
+Brendan Kehoe for his ongoing work with g++.
+
+@item
+Oliver M. Kellogg of Deutsche Aerospace contributed the port to the
+MIL-STD-1750A@.
+
+@item
+Richard Kenner of the New York University Ultracomputer Research
+Laboratory wrote the machine descriptions for the AMD 29000, the DEC
+Alpha, the IBM RT PC, and the IBM RS/6000 as well as the support for
+instruction attributes.  He also made changes to better support RISC
+processors including changes to common subexpression elimination,
+strength reduction, function calling sequence handling, and condition
+code support, in addition to generalizing the code for frame pointer
+elimination and delay slot scheduling.  Richard Kenner was also the
+head maintainer of GCC for several years.
+
+@item
+Mumit Khan for various contributions to the cygwin and mingw32 ports and
+maintaining binary releases for Windows hosts.
+
+@item
+Robin Kirkham for cpu32 support.
+
+@item
+Mark Klein for PA improvements.
+
+@item
+Thomas Koenig for various bugfixes.
+
+@item
+Bruce Korb for the new and improved fixincludes code.
+
+@item
+Benjamin Kosnik for his g++ work.
+
+@item
+Charles LaBrec contributed the support for the Integrated Solutions
+68020 system.
+
+@item
+Jeff Law for his direction via the steering committee, coordinating the
+entire egcs project and GCC 2.95, rolling out snapshots and releases,
+handling merges from GCC2, reviewing tons of patches that might have
+fallen through the cracks else, and random but extensive hacking.
+
+@item
+Marc Lehmann for his direction via the steering committee and helping
+with analysis and improvements of x86 performance.
+
+@item
+Ted Lemon wrote parts of the RTL reader and printer.
+
+@item
+Kriang Lerdsuwanakij for improvements to demangler and various c++ fixes.
+
+@item
+Warren Levy major work on libgcj (Java Runtime Library) and random
+work on the Java front end.
+
+@item
+Alain Lichnewsky ported GCC to the Mips cpu.
+
+@item
+Robert Lipe for OpenServer support, new testsuites, testing, etc.
+
+@item
+Weiwen Liu for testing and various bugfixes.
+
+@item
+Dave Love for his ongoing work with the Fortran front end and
+runtime libraries.
+
+@item
+Martin von L@"owis for internal consistency checking infrastructure,
+and various C++ improvements including namespace support.
+
+@item
+H.J. Lu for his previous contributions to the steering committee, many x86
+bug reports, prototype patches, and keeping the Linux ports working.
+
+@item
+Greg McGary for random fixes and (someday) bounded pointers.
+
+@item
+Andrew MacLeod for his ongoing work in building a real EH system,
+various code generation improvements, work on the global optimizer, etc.
+
+@item
+Vladimir Makarov for hacking some ugly i960 problems, PowerPC
+hacking improvements to compile-time performance and overall knowledge
+and direction in the area of instruction scheduling.
+
+@item
+Bob Manson for his behind the scenes work on dejagnu.
+
+@item
+Michael Meissner for LRS framework, ia32, m32r, v850, m88k, MIPS powerpc, haifa,
+ECOFF debug support, and other assorted hacking.
+
+@item
+Jason Merrill for his direction via the steering committee and leading
+the g++ effort.
+
+@item
+David Miller for his direction via the steering committee, lots of
+SPARC work, improvements in jump.c and interfacing with the Linux kernel
+developers.
+
+@item
+Gary Miller ported GCC to Charles River Data Systems machines.
+
+@item
+Mark Mitchell for his direction via the steering committee, mountains of
+C++ work, load/store hoisting out of loops, alias analysis improvements,
+ISO C @code{restrict} support, and serving as release manager for GCC 3.0.
+
+@item
+Alan Modra for various Linux bits and testing.
+
+@item
+Toon Moene for his direction via the steering committee, Fortran
+maintenance, and his ongoing work to make us make Fortran run fast.
+
+@item
+Jason Molenda for major help in the care and feeding of all the services
+on the gcc.gnu.org (formerly egcs.cygnus.com) machine---mail, web
+services, ftp services, etc etc.
+
+@item
+Catherine Moore for fixing various ugly problems we have sent her
+way, including the haifa bug which was killing the Alpha & PowerPC Linux
+kernels.
+
+@item
+David Mosberger-Tang for various Alpha improvements.
+
+@item
+Stephen Moshier contributed the floating point emulator that assists in
+cross-compilation and permits support for floating point numbers wider
+than 64 bits and for ISO C99 support.
+
+@item
+Bill Moyer for his behind the scenes work on various issues.
+
+@item
+Philippe De Muyter for his work on the m68k port.
+
+@item
+Joseph S. Myers for his work on the PDP-11 port, format checking and ISO
+C99 support, and continuous emphasis on (and contributions to) documentation.
+
+@item
+Nathan Myers for his work on libstdc++-v3.
+
+@item
+NeXT, Inc.@: donated the front end that supports the Objective-C
+language.
+
+@item
+Hans-Peter Nilsson for the CRIS and MMIX ports, improvements to the search
+engine setup, various documentation fixes and other small fixes.
+
+@item
+Geoff Noer for this work on getting cygwin native builds working.
+
+@item
+Alexandre Oliva for various build infrastructure improvements, scripts and
+amazing testing work.
+
+@item
+Melissa O'Neill for various NeXT fixes.
+
+@item
+Rainer Orth for random MIPS work, including improvements to our o32
+ABI support, improvements to dejagnu's MIPS support, etc.
+
+@item
+Paul Petersen wrote the machine description for the Alliant FX/8.
+
+@item
+Alexandre Petit-Bianco for his Java work.
+
+@item
+Matthias Pfaller for major improvements to the NS32k port.
+
+@item
+Gerald Pfeifer for his direction via the steering committee, pointing
+out lots of problems we need to solve, maintenance of the web pages, and
+taking care of documentation maintenance in general.
+
+@item
+Ovidiu Predescu for his work on the ObjC front end and runtime libraries.
+
+@item
+Ken Raeburn for various improvements to checker, mips ports and various
+cleanups in the compiler.
+
+@item
+David Reese of Sun Microsystems contributed to the Solaris on PowerPC
+port.
+@item
+Gabriel Dos Reis for contributions and maintenance of libstdc++-v3,
+including valarray implementation and limits support.
+
+@item
+Joern Rennecke for maintaining the sh port, loop, regmove & reload
+hacking.
+
+@item
+Gavin Romig-Koch for lots of behind the scenes MIPS work.
+
+@item
+Ken Rose for fixes to our delay slot filling code.
+
+@item
+Paul Rubin wrote most of the preprocessor.
+
+@item
+Juha Sarlin for improvements to the H8 code generator.
+
+@item
+Greg Satz assisted in making GCC work on HP-UX for the 9000 series 300.
+
+@item
+Peter Schauer wrote the code to allow debugging to work on the Alpha.
+
+@item
+William Schelter did most of the work on the Intel 80386 support.
+
+@item
+Bernd Schmidt for various code generation improvements and major
+work in the reload pass as well a serving as release manager for
+GCC 2.95.3.
+
+@item
+Andreas Schwab for his work on the m68k port.
+
+@item
+Joel Sherrill for his direction via the steering committee, RTEMS
+contributions and RTEMS testing.
+
+@item
+Nathan Sidwell for many C++ fixes/improvements.
+
+@item
+Jeffrey Siegal for helping RMS with the original design of GCC, some
+code which handles the parse tree and RTL data structures, constant
+folding and help with the original VAX & m68k ports.
+
+@item
+Franz Sirl for his ongoing work with making the PPC port stable
+for linux.
+
+@item
+Andrey Slepuhin for assorted AIX hacking.
+
+@item
+Christopher Smith did the port for Convex machines.
+
+@item
+Randy Smith finished the Sun FPA support.
+
+@item
+Scott Snyder for various fixes.
+
+@item
+Richard Stallman, for writing the original gcc and launching the GNU project.
+
+@item
+Jan Stein of the Chalmers Computer Society provided support for
+Genix, as well as part of the 32000 machine description.
+
+@item
+Nigel Stephens for various mips16 related fixes/improvements.
+
+@item
+Jonathan Stone wrote the machine description for the Pyramid computer.
+
+@item
+Graham Stott for various infrastructure improvements.
+
+@item
+Mike Stump for his Elxsi port, g++ contributions over the years and more
+recently his vxworks contributions
+
+@item
+Shigeya Suzuki for this fixes for the bsdi platforms.
+
+@item
+Ian Lance Taylor for his mips16 work, general configury hacking,
+fixincludes, etc.
+
+@item
+Holger Teutsch provided the support for the Clipper cpu.
+
+@item
+Gary Thomas for his ongoing work to make the PPC work for Linux.
+
+@item
+Philipp Thomas for random bugfixes throughout the compiler
+
+@item
+Kresten Krab Thorup wrote the run time support for the Objective-C
+language.
+
+@item
+Michael Tiemann for random bugfixes the first instruction scheduler,
+initial C++ support, function integration, NS32k, sparc and M88k
+machine description work, delay slot scheduling.
+
+@item
+Teemu Torma for thread safe exception handling support.
+
+@item
+Leonard Tower wrote parts of the parser, RTL generator, and RTL
+definitions, and of the VAX machine description.
+
+@item
+Tom Tromey for internationalization support and his Java work.
+
+@item
+Lassi Tuura for improvements to config.guess to determine HP processor
+types.
+
+@item
+Todd Vierling for contributions for NetBSD ports.
+
+@item
+Dean Wakerley for converting the install documentation from HTML to texinfo
+in time for GCC 3.0.
+
+@item
+Krister Walfridsson for random bugfixes.
+
+@item
+John Wehle for various improvements for the x86 code generator,
+related infrastructure improvements to help x86 code generation,
+value range propagation and other work, WE32k port.
+
+@item
+Zack Weinberg for major work on cpplib and various other bugfixes.
+
+@item
+Dale Wiles helped port GCC to the Tahoe.
+
+@item
+Bob Wilson from Tensilica, Inc.@: for the Xtensa port.
+
+@item
+Jim Wilson for his direction via the steering committee, tackling hard
+problems in various places that nobody else wanted to work on, strength
+reduction and other loop optimizations.
+
+@item
+Carlo Wood for various fixes.
+
+@item
+Tom Wood for work on the m88k port.
+
+@item
+Masanobu Yuhara of Fujitsu Laboratories implemented the machine
+description for the Tron architecture (specifically, the Gmicro).
+
+@item
+Kevin Zachmann helped ported GCC to the Tahoe.
+
+@end itemize
+
+
+We'd also like to thank the folks who have contributed time and energy in
+testing GCC:
+
+@itemize @bullet
+@item
+David Billinghurst
+
+@item
+Horst von Brand
+
+@item
+Rodney Brown
+
+@item
+Joe Buck
+
+@item
+Craig Burley
+
+@item
+Ulrich Drepper
+
+@item
+David Edelsohn
+
+@item
+Yung Shing Gene
+
+@item
+Kaveh Ghazi
+
+@item
+Kate Hedstrom
+
+@item
+Richard Henderson
+
+@item
+Manfred Hollstein
+
+@item
+Kamil Iskra
+
+@item
+Christian Joensson
+
+@item
+Jeff Law
+
+@item
+Robert Lipe
+
+@item
+Damon Love
+
+@item
+Dave Love
+
+@item
+H.J. Lu
+
+@item
+Mumit Khan
+
+@item
+Matthias Klose
+
+@item
+Martin Knoblauch
+
+@item
+David Miller
+
+@item
+Toon Moene
+
+@item
+Matthias Mueller
+
+@item
+Alexandre Oliva
+
+@item
+Richard Polton
+
+@item
+David Rees
+
+@item
+Peter Schmid
+
+@item
+David Schuler
+
+@item
+Vin Shelton
+
+@item
+Franz Sirl
+
+@item
+Mike Stump
+
+@item
+Carlo Wood
+
+@item
+And many others
+@end itemize
+
+And finally we'd like to thank everyone who uses the compiler, submits bug
+reports and generally reminds us why we're doing this work in the first place.
diff --git a/contrib/gcc/doc/contribute.texi b/contrib/gcc/doc/contribute.texi
new file mode 100644
index 0000000..f9a5f97
--- /dev/null
+++ b/contrib/gcc/doc/contribute.texi
@@ -0,0 +1,25 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+@c 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Contributing
+@chapter Contributing to GCC Development
+
+If you would like to help pretest GCC releases to assure they work well,
+our current development sources are available by CVS (see
+@uref{http://gcc.gnu.org/cvs.html}).  Source and binary snapshots are
+also available for FTP; see @uref{http://gcc.gnu.org/snapshots.html}.
+
+If you would like to work on improvements to GCC, please read the
+advice at these URLs:
+
+@smallexample
+@uref{http://gcc.gnu.org/contribute.html} 
+@uref{http://gcc.gnu.org/contributewhy.html}
+@end smallexample
+
+@noindent
+for information on how to make useful contributions and avoid
+duplication of effort.  Suggested projects are listed at
+@uref{http://gcc.gnu.org/projects/}.
diff --git a/contrib/gcc/doc/cpp.texi b/contrib/gcc/doc/cpp.texi
new file mode 100644
index 0000000..3572384
--- /dev/null
+++ b/contrib/gcc/doc/cpp.texi
@@ -0,0 +1,4302 @@
+\input texinfo
+@setfilename cpp.info
+@settitle The C Preprocessor
+@setchapternewpage off
+@c @smallbook
+@c @cropmarks
+@c @finalout
+
+@macro copyrightnotice
+@c man begin COPYRIGHT
+Copyright @copyright{} 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996,
+1997, 1998, 1999, 2000, 2001
+Free Software Foundation, Inc.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.1 or
+any later version published by the Free Software Foundation.  A copy of
+the license is included in the
+@c man end
+section entitled ``GNU Free Documentation License''.
+@ignore
+@c man begin COPYRIGHT
+man page gfdl(7).
+@c man end
+@end ignore
+@end macro
+
+@macro covertexts
+@c man begin COPYRIGHT
+This manual contains no Invariant Sections.  The Front-Cover Texts are
+(a) (see below), and the Back-Cover Texts are (b) (see below).
+
+(a) The FSF's Front-Cover Text is:
+
+     A GNU Manual
+
+(b) The FSF's Back-Cover Text is:
+
+     You have freedom to copy and modify this GNU Manual, like GNU
+     software.  Copies published by the Free Software Foundation raise
+     funds for GNU development.
+@c man end
+@end macro
+
+@macro gcctabopt{body}
+@code{\body\}
+@end macro
+
+@ifinfo
+@dircategory Programming
+@direntry
+* Cpp: (cpp).		       The GNU C preprocessor.
+@end direntry
+@end ifinfo
+
+@titlepage
+@title The C Preprocessor
+@subtitle Last revised April 2001
+@subtitle for GCC version 3
+@author Richard M. Stallman
+@author Zachary Weinberg
+@page
+@c There is a fill at the bottom of the page, so we need a filll to
+@c override it.
+@vskip 0pt plus 1filll
+@copyrightnotice{}
+@covertexts{}
+@end titlepage
+@contents
+@page
+
+@node Top
+@top
+The C preprocessor implements the macro language used to transform C,
+C++, and Objective-C programs before they are compiled.  It can also be
+useful on its own.
+
+@menu
+* Overview::
+* Header Files::
+* Macros::
+* Conditionals::
+* Diagnostics::
+* Line Control::
+* Pragmas::
+* Other Directives::
+* Preprocessor Output::
+* Traditional Mode::
+* Implementation Details::
+* Invocation::
+* GNU Free Documentation License::
+* Index of Directives::
+* Concept Index::
+
+@detailmenu
+ --- The Detailed Node Listing ---
+
+Overview
+
+* Initial processing::
+* Tokenization::
+* The preprocessing language::
+
+Header Files
+
+* Include Syntax::
+* Include Operation::
+* Search Path::
+* Once-Only Headers::
+* Computed Includes::
+* Wrapper Headers::
+* System Headers::
+
+Macros
+
+* Object-like Macros::
+* Function-like Macros::
+* Macro Arguments::
+* Stringification::
+* Concatenation::
+* Variadic Macros::
+* Predefined Macros::
+* Undefining and Redefining Macros::
+* Macro Pitfalls::
+
+Predefined Macros
+
+* Standard Predefined Macros::
+* Common Predefined Macros::
+* System-specific Predefined Macros::
+* C++ Named Operators::
+
+Macro Pitfalls
+
+* Misnesting::
+* Operator Precedence Problems::
+* Swallowing the Semicolon::
+* Duplication of Side Effects::
+* Self-Referential Macros::
+* Argument Prescan::
+* Newlines in Arguments::
+
+Conditionals
+
+* Conditional Uses::
+* Conditional Syntax::
+* Deleted Code::
+
+Conditional Syntax
+
+* Ifdef::
+* If::
+* Defined::
+* Else::
+* Elif::
+
+Implementation Details
+
+* Implementation-defined behavior::
+* Implementation limits::
+* Obsolete Features::
+* Differences from previous versions::
+
+Obsolete Features
+
+* Assertions::
+* Obsolete once-only headers::
+* Miscellaneous obsolete features::
+
+@end detailmenu
+@end menu
+
+@ifnottex
+@copyrightnotice{}
+@covertexts{}
+@end ifnottex
+
+@node Overview
+@chapter Overview
+@c man begin DESCRIPTION
+The C preprocessor, often known as @dfn{cpp}, is a @dfn{macro processor}
+that is used automatically by the C compiler to transform your program
+before compilation.  It is called a macro processor because it allows
+you to define @dfn{macros}, which are brief abbreviations for longer
+constructs.
+
+The C preprocessor is intended to be used only with C, C++, and
+Objective-C source code.  In the past, it has been abused as a general
+text processor.  It will choke on input which does not obey C's lexical
+rules.  For example, apostrophes will be interpreted as the beginning of
+character constants, and cause errors.  Also, you cannot rely on it
+preserving characteristics of the input which are not significant to
+C-family languages.  If a Makefile is preprocessed, all the hard tabs
+will be removed, and the Makefile will not work.
+
+Having said that, you can often get away with using cpp on things which
+are not C@.  Other Algol-ish programming languages are often safe
+(Pascal, Ada, etc.) So is assembly, with caution.  @option{-traditional}
+mode preserves more white space, and is otherwise more permissive.  Many
+of the problems can be avoided by writing C or C++ style comments
+instead of native language comments, and keeping macros simple.
+
+Wherever possible, you should use a preprocessor geared to the language
+you are writing in.  Modern versions of the GNU assembler have macro
+facilities.  Most high level programming languages have their own
+conditional compilation and inclusion mechanism.  If all else fails,
+try a true general text processor, such as GNU M4.
+
+C preprocessors vary in some details.  This manual discusses the GNU C
+preprocessor, which provides a small superset of the features of ISO
+Standard C@.  In its default mode, the GNU C preprocessor does not do a
+few things required by the standard.  These are features which are
+rarely, if ever, used, and may cause surprising changes to the meaning
+of a program which does not expect them.  To get strict ISO Standard C,
+you should use the @option{-std=c89} or @option{-std=c99} options, depending
+on which version of the standard you want.  To get all the mandatory
+diagnostics, you must also use @option{-pedantic}.  @xref{Invocation}.
+@c man end
+
+@menu
+* Initial processing::
+* Tokenization::
+* The preprocessing language::
+@end menu
+
+@node Initial processing
+@section Initial processing
+
+The preprocessor performs a series of textual transformations on its
+input.  These happen before all other processing.  Conceptually, they
+happen in a rigid order, and the entire file is run through each
+transformation before the next one begins.  GNU CPP actually does them
+all at once, for performance reasons.  These transformations correspond
+roughly to the first three ``phases of translation'' described in the C
+standard.
+
+@enumerate
+@item
+@cindex character sets
+@cindex line endings
+The input file is read into memory and broken into lines.
+
+GNU CPP expects its input to be a text file, that is, an unstructured
+stream of ASCII characters, with some characters indicating the end of a
+line of text.  Extended ASCII character sets, such as ISO Latin-1 or
+Unicode encoded in UTF-8, are also acceptable.  Character sets that are
+not strict supersets of seven-bit ASCII will not work.  We plan to add
+complete support for international character sets in a future release.
+
+Different systems use different conventions to indicate the end of a
+line.  GCC accepts the ASCII control sequences @kbd{LF}, @kbd{@w{CR
+LF}}, @kbd{CR}, and @kbd{@w{LF CR}} as end-of-line markers.  The first
+three are the canonical sequences used by Unix, DOS and VMS, and the
+classic Mac OS (before OSX) respectively.  You may therefore safely copy
+source code written on any of those systems to a different one and use
+it without conversion.  (GCC may lose track of the current line number
+if a file doesn't consistently use one convention, as sometimes happens
+when it is edited on computers with different conventions that share a
+network file system.)  @kbd{@w{LF CR}} is included because it has been
+reported as an end-of-line marker under exotic conditions.
+
+If the last line of any input file lacks an end-of-line marker, the end
+of the file is considered to implicitly supply one.  The C standard says
+that this condition provokes undefined behavior, so GCC will emit a
+warning message.
+
+@item
+@cindex trigraphs
+If trigraphs are enabled, they are replaced by their corresponding
+single characters.
+
+These are nine three-character sequences, all starting with @samp{??},
+that are defined by ISO C to stand for single characters.  They permit
+obsolete systems that lack some of C's punctuation to use C@.  For
+example, @samp{??/} stands for @samp{\}, so @t{'??/n'} is a character
+constant for a newline.  By default, GCC ignores trigraphs, but if you
+request a strictly conforming mode with the @option{-std} option, then
+it converts them.
+
+Trigraphs are not popular and many compilers implement them incorrectly.
+Portable code should not rely on trigraphs being either converted or
+ignored.  If you use the @option{-Wall} or @option{-Wtrigraphs} options,
+GCC will warn you when a trigraph would change the meaning of your
+program if it were converted.
+
+In a string constant, you can prevent a sequence of question marks from
+being confused with a trigraph by inserting a backslash between the
+question marks.  @t{"(??\?)"} is the string @samp{(???)}, not
+@samp{(?]}.  Traditional C compilers do not recognize this idiom.
+
+The nine trigraphs and their replacements are
+
+@example
+Trigraph:       ??(  ??)  ??<  ??>  ??=  ??/  ??'  ??!  ??-
+Replacement:      [    ]    @{    @}    #    \    ^    |    ~
+@end example
+
+@item
+@cindex continued lines
+@cindex backslash-newline
+Continued lines are merged into one long line.
+
+A continued line is a line which ends with a backslash, @samp{\}.  The
+backslash is removed and the following line is joined with the current
+one.  No space is inserted, so you may split a line anywhere, even in
+the middle of a word.  (It is generally more readable to split lines
+only at white space.)
+
+The trailing backslash on a continued line is commonly referred to as a
+@dfn{backslash-newline}.
+
+If there is white space between a backslash and the end of a line, that
+is still a continued line.  However, as this is usually the result of an
+editing mistake, and many compilers will not accept it as a continued
+line, GCC will warn you about it.
+
+@item
+@cindex comments
+@cindex line comments
+@cindex block comments
+All comments are replaced with single spaces.
+
+There are two kinds of comments.  @dfn{Block comments} begin with
+@samp{/*} and continue until the next @samp{*/}.  Block comments do not
+nest:
+
+@example
+/* @r{this is} /* @r{one comment} */ @r{text outside comment}
+@end example
+
+@dfn{Line comments} begin with @samp{//} and continue to the end of the
+current line.  Line comments do not nest either, but it does not matter,
+because they would end in the same place anyway.
+
+@example
+// @r{this is} // @r{one comment}
+@r{text outside comment}
+@end example
+@end enumerate
+
+It is safe to put line comments inside block comments, or vice versa.
+
+@example
+@group
+/* @r{block comment}
+   // @r{contains line comment}
+   @r{yet more comment}
+ */ @r{outside comment}
+
+// @r{line comment} /* @r{contains block comment} */
+@end group
+@end example
+
+But beware of commenting out one end of a block comment with a line
+comment.
+
+@example
+@group
+ // @r{l.c.}  /* @r{block comment begins}
+    @r{oops! this isn't a comment anymore} */
+@end group
+@end example
+
+Comments are not recognized within string literals.  @t{@w{"/* blah
+*/"}} is the string constant @samp{@w{/* blah */}}, not an empty string.
+
+Line comments are not in the 1989 edition of the C standard, but they
+are recognized by GCC as an extension.  In C++ and in the 1999 edition
+of the C standard, they are an official part of the language.
+
+Since these transformations happen before all other processing, you can
+split a line mechanically with backslash-newline anywhere.  You can
+comment out the end of a line.  You can continue a line comment onto the
+next line with backslash-newline.  You can even split @samp{/*},
+@samp{*/}, and @samp{//} onto multiple lines with backslash-newline.
+For example:
+
+@example
+@group
+/\
+*
+*/ # /*
+*/ defi\
+ne FO\
+O 10\
+20
+@end group
+@end example
+
+@noindent
+is equivalent to @code{@w{#define FOO 1020}}.  All these tricks are
+extremely confusing and should not be used in code intended to be
+readable.
+
+There is no way to prevent a backslash at the end of a line from being
+interpreted as a backslash-newline.
+
+@example
+"foo\\
+bar"
+@end example
+
+@noindent
+is equivalent to @code{"foo\bar"}, not to @code{"foo\\bar"}.  To avoid
+having to worry about this, do not use the deprecated GNU extension
+which permits multi-line strings.  Instead, use string literal
+concatenation:
+
+@example
+   "foo\\"
+   "bar"
+@end example
+
+@noindent
+Your program will be more portable this way, too.
+
+@node Tokenization
+@section Tokenization
+
+@cindex tokens
+@cindex preprocessing tokens
+After the textual transformations are finished, the input file is
+converted into a sequence of @dfn{preprocessing tokens}.  These mostly
+correspond to the syntactic tokens used by the C compiler, but there are
+a few differences.  White space separates tokens; it is not itself a
+token of any kind.  Tokens do not have to be separated by white space,
+but it is often necessary to avoid ambiguities.
+
+When faced with a sequence of characters that has more than one possible
+tokenization, the preprocessor is greedy.  It always makes each token,
+starting from the left, as big as possible before moving on to the next
+token.  For instance, @code{a+++++b} is interpreted as
+@code{@w{a ++ ++ + b}}, not as @code{@w{a ++ + ++ b}}, even though the
+latter tokenization could be part of a valid C program and the former
+could not.
+
+Once the input file is broken into tokens, the token boundaries never
+change, except when the @samp{##} preprocessing operator is used to paste
+tokens together.  @xref{Concatenation}.  For example,
+
+@example
+@group
+#define foo() bar
+foo()baz
+     @expansion{} bar baz
+@emph{not}
+     @expansion{} barbaz
+@end group
+@end example
+
+The compiler does not re-tokenize the preprocessor's output.  Each
+preprocessing token becomes one compiler token.
+
+@cindex identifiers
+Preprocessing tokens fall into five broad classes: identifiers,
+preprocessing numbers, string literals, punctuators, and other.  An
+@dfn{identifier} is the same as an identifier in C: any sequence of
+letters, digits, or underscores, which begins with a letter or
+underscore.  Keywords of C have no significance to the preprocessor;
+they are ordinary identifiers.  You can define a macro whose name is a
+keyword, for instance.  The only identifier which can be considered a
+preprocessing keyword is @code{defined}.  @xref{Defined}.
+
+This is mostly true of other languages which use the C preprocessor.
+However, a few of the keywords of C++ are significant even in the
+preprocessor.  @xref{C++ Named Operators}.
+
+In the 1999 C standard, identifiers may contain letters which are not
+part of the ``basic source character set,'' at the implementation's
+discretion (such as accented Latin letters, Greek letters, or Chinese
+ideograms).  This may be done with an extended character set, or the
+@samp{\u} and @samp{\U} escape sequences.  GCC does not presently
+implement either feature in the preprocessor or the compiler.
+
+As an extension, GCC treats @samp{$} as a letter.  This is for
+compatibility with some systems, such as VMS, where @samp{$} is commonly
+used in system-defined function and object names.  @samp{$} is not a
+letter in strictly conforming mode, or if you specify the @option{-$}
+option.  @xref{Invocation}.
+
+@cindex numbers
+@cindex preprocessing numbers
+A @dfn{preprocessing number} has a rather bizarre definition.  The
+category includes all the normal integer and floating point constants
+one expects of C, but also a number of other things one might not
+initially recognize as a number.  Formally, preprocessing numbers begin
+with an optional period, a required decimal digit, and then continue
+with any sequence of letters, digits, underscores, periods, and
+exponents.  Exponents are the two-character sequences @samp{e+},
+@samp{e-}, @samp{E+}, @samp{E-}, @samp{p+}, @samp{p-}, @samp{P+}, and
+@samp{P-}.  (The exponents that begin with @samp{p} or @samp{P} are new
+to C99.  They are used for hexadecimal floating-point constants.)
+
+The purpose of this unusual definition is to isolate the preprocessor
+from the full complexity of numeric constants.  It does not have to
+distinguish between lexically valid and invalid floating-point numbers,
+which is complicated.  The definition also permits you to split an
+identifier at any position and get exactly two tokens, which can then be
+pasted back together with the @samp{##} operator.
+
+It's possible for preprocessing numbers to cause programs to be
+misinterpreted.  For example, @code{0xE+12} is a preprocessing number
+which does not translate to any valid numeric constant, therefore a
+syntax error.  It does not mean @code{@w{0xE + 12}}, which is what you
+might have intended.
+
+@cindex string literals
+@cindex string constants
+@cindex character constants
+@cindex header file names
+@c the @: prevents makeinfo from turning '' into ".
+@dfn{String literals} are string constants, character constants, and
+header file names (the argument of @samp{#include}).@footnote{The C
+standard uses the term @dfn{string literal} to refer only to what we are
+calling @dfn{string constants}.}  String constants and character
+constants are straightforward: @t{"@dots{}"} or @t{'@dots{}'}.  In
+either case embedded quotes should be escaped with a backslash:
+@t{'\'@:'} is the character constant for @samp{'}.  There is no limit on
+the length of a character constant, but the value of a character
+constant that contains more than one character is
+implementation-defined.  @xref{Implementation Details}.
+
+Header file names either look like string constants, @t{"@dots{}"}, or are
+written with angle brackets instead, @t{<@dots{}>}.  In either case,
+backslash is an ordinary character.  There is no way to escape the
+closing quote or angle bracket.  The preprocessor looks for the header
+file in different places depending on which form you use.  @xref{Include
+Operation}.
+
+In standard C, no string literal may extend past the end of a line.  GNU
+CPP accepts multi-line string constants, but not multi-line character
+constants or header file names.  This extension is deprecated and will
+be removed in GCC 3.1.  You may use continued lines instead, or string
+constant concatenation.  @xref{Differences from previous versions}.
+
+@cindex punctuators
+@cindex digraphs
+@cindex alternative tokens
+@dfn{Punctuators} are all the usual bits of punctuation which are
+meaningful to C and C++.  All but three of the punctuation characters in
+ASCII are C punctuators.  The exceptions are @samp{@@}, @samp{$}, and
+@samp{`}.  In addition, all the two- and three-character operators are
+punctuators.  There are also six @dfn{digraphs}, which the C++ standard
+calls @dfn{alternative tokens}, which are merely alternate ways to spell
+other punctuators.  This is a second attempt to work around missing
+punctuation in obsolete systems.  It has no negative side effects,
+unlike trigraphs, but does not cover as much ground.  The digraphs and
+their corresponding normal punctuators are:
+
+@example
+Digraph:        <%  %>  <:  :>  %:  %:%:
+Punctuator:      @{   @}   [   ]   #    ##
+@end example
+
+@cindex other tokens
+Any other single character is considered ``other.'' It is passed on to
+the preprocessor's output unmolested.  The C compiler will almost
+certainly reject source code containing ``other'' tokens.  In ASCII, the
+only other characters are @samp{@@}, @samp{$}, @samp{`}, and control
+characters other than NUL (all bits zero).  (Note that @samp{$} is
+normally considered a letter.)  All characters with the high bit set
+(numeric range 0x7F--0xFF) are also ``other'' in the present
+implementation.  This will change when proper support for international
+character sets is added to GCC@.
+
+NUL is a special case because of the high probability that its
+appearance is accidental, and because it may be invisible to the user
+(many terminals do not display NUL at all).  Within comments, NULs are
+silently ignored, just as any other character would be.  In running
+text, NUL is considered white space.  For example, these two directives
+have the same meaning.
+
+@example
+#define X^@@1
+#define X 1
+@end example
+
+@noindent
+(where @samp{^@@} is ASCII NUL)@.  Within string or character constants,
+NULs are preserved.  In the latter two cases the preprocessor emits a
+warning message.
+
+@node The preprocessing language
+@section The preprocessing language
+@cindex directives
+@cindex preprocessing directives
+@cindex directive line
+@cindex directive name
+
+After tokenization, the stream of tokens may simply be passed straight
+to the compiler's parser.  However, if it contains any operations in the
+@dfn{preprocessing language}, it will be transformed first.  This stage
+corresponds roughly to the standard's ``translation phase 4'' and is
+what most people think of as the preprocessor's job.
+
+The preprocessing language consists of @dfn{directives} to be executed
+and @dfn{macros} to be expanded.  Its primary capabilities are:
+
+@itemize @bullet
+@item
+Inclusion of header files.  These are files of declarations that can be
+substituted into your program.
+
+@item
+Macro expansion.  You can define @dfn{macros}, which are abbreviations
+for arbitrary fragments of C code.  The preprocessor will replace the
+macros with their definitions throughout the program.  Some macros are
+automatically defined for you.
+
+@item
+Conditional compilation.  You can include or exclude parts of the
+program according to various conditions.
+
+@item
+Line control.  If you use a program to combine or rearrange source files
+into an intermediate file which is then compiled, you can use line
+control to inform the compiler where each source line originally came
+from.
+
+@item
+Diagnostics.  You can detect problems at compile time and issue errors
+or warnings.
+@end itemize
+
+There are a few more, less useful, features.
+
+Except for expansion of predefined macros, all these operations are
+triggered with @dfn{preprocessing directives}.  Preprocessing directives
+are lines in your program that start with @samp{#}.  Whitespace is
+allowed before and after the @samp{#}.  The @samp{#} is followed by an
+identifier, the @dfn{directive name}.  It specifies the operation to
+perform.  Directives are commonly referred to as @samp{#@var{name}}
+where @var{name} is the directive name.  For example, @samp{#define} is
+the directive that defines a macro.
+
+The @samp{#} which begins a directive cannot come from a macro
+expansion.  Also, the directive name is not macro expanded.  Thus, if
+@code{foo} is defined as a macro expanding to @code{define}, that does
+not make @samp{#foo} a valid preprocessing directive.
+
+The set of valid directive names is fixed.  Programs cannot define new
+preprocessing directives.
+
+Some directives require arguments; these make up the rest of the
+directive line and must be separated from the directive name by
+whitespace.  For example, @samp{#define} must be followed by a macro
+name and the intended expansion of the macro.
+
+A preprocessing directive cannot cover more than one line.  The line
+may, however, be continued with backslash-newline, or by a block comment
+which extends past the end of the line.  In either case, when the
+directive is processed, the continuations have already been merged with
+the first line to make one long line.
+
+@node Header Files
+@chapter Header Files
+
+@cindex header file
+A header file is a file containing C declarations and macro definitions
+(@pxref{Macros}) to be shared between several source files.  You request
+the use of a header file in your program by @dfn{including} it, with the
+C preprocessing directive @samp{#include}.
+
+Header files serve two purposes.
+
+@itemize @bullet
+@item
+@cindex system header files
+System header files declare the interfaces to parts of the operating
+system.  You include them in your program to supply the definitions and
+declarations you need to invoke system calls and libraries.
+
+@item
+Your own header files contain declarations for interfaces between the
+source files of your program.  Each time you have a group of related
+declarations and macro definitions all or most of which are needed in
+several different source files, it is a good idea to create a header
+file for them.
+@end itemize
+
+Including a header file produces the same results as copying the header
+file into each source file that needs it.  Such copying would be
+time-consuming and error-prone.  With a header file, the related
+declarations appear in only one place.  If they need to be changed, they
+can be changed in one place, and programs that include the header file
+will automatically use the new version when next recompiled.  The header
+file eliminates the labor of finding and changing all the copies as well
+as the risk that a failure to find one copy will result in
+inconsistencies within a program.
+
+In C, the usual convention is to give header files names that end with
+@file{.h}.  It is most portable to use only letters, digits, dashes, and
+underscores in header file names, and at most one dot.
+
+@menu
+* Include Syntax::
+* Include Operation::
+* Search Path::
+* Once-Only Headers::
+* Computed Includes::
+* Wrapper Headers::
+* System Headers::
+@end menu
+
+@node Include Syntax
+@section Include Syntax
+
+@findex #include
+Both user and system header files are included using the preprocessing
+directive @samp{#include}.  It has two variants:
+
+@table @code
+@item #include <@var{file}>
+This variant is used for system header files.  It searches for a file
+named @var{file} in a standard list of system directories.  You can prepend
+directories to this list with the @option{-I} option (@pxref{Invocation}).
+
+@item #include "@var{file}"
+This variant is used for header files of your own program.  It searches
+for a file named @var{file} first in the directory containing the
+current file, then in the same directories used for @code{<@var{file}>}.
+@end table
+
+The argument of @samp{#include}, whether delimited with quote marks or
+angle brackets, behaves like a string constant in that comments are not
+recognized, and macro names are not expanded.  Thus, @code{@w{#include
+<x/*y>}} specifies inclusion of a system header file named @file{x/*y}.
+
+However, if backslashes occur within @var{file}, they are considered
+ordinary text characters, not escape characters.  None of the character
+escape sequences appropriate to string constants in C are processed.
+Thus, @code{@w{#include "x\n\\y"}} specifies a filename containing three
+backslashes.  (Some systems interpret @samp{\} as a pathname separator.
+All of these also interpret @samp{/} the same way.  It is most portable
+to use only @samp{/}.)
+
+It is an error if there is anything (other than comments) on the line
+after the file name.
+
+@node Include Operation
+@section Include Operation
+
+The @samp{#include} directive works by directing the C preprocessor to
+scan the specified file as input before continuing with the rest of the
+current file.  The output from the preprocessor contains the output
+already generated, followed by the output resulting from the included
+file, followed by the output that comes from the text after the
+@samp{#include} directive.  For example, if you have a header file
+@file{header.h} as follows,
+
+@example
+char *test (void);
+@end example
+
+@noindent
+and a main program called @file{program.c} that uses the header file,
+like this,
+
+@example
+int x;
+#include "header.h"
+
+int
+main (void)
+@{
+  puts (test ());
+@}
+@end example
+
+@noindent
+the compiler will see the same token stream as it would if
+@file{program.c} read
+
+@example
+int x;
+char *test (void);
+
+int
+main (void)
+@{
+  puts (test ());
+@}
+@end example
+
+Included files are not limited to declarations and macro definitions;
+those are merely the typical uses.  Any fragment of a C program can be
+included from another file.  The include file could even contain the
+beginning of a statement that is concluded in the containing file, or
+the end of a statement that was started in the including file.  However,
+a comment or a string or character constant may not start in the
+included file and finish in the including file.  An unterminated
+comment, string constant or character constant in an included file is
+considered to end (with an error message) at the end of the file.
+
+To avoid confusion, it is best if header files contain only complete
+syntactic units---function declarations or definitions, type
+declarations, etc.
+
+The line following the @samp{#include} directive is always treated as a
+separate line by the C preprocessor, even if the included file lacks a
+final newline.
+
+@node Search Path
+@section Search Path
+
+GCC looks in several different places for headers.  On a normal Unix
+system, if you do not instruct it otherwise, it will look for headers
+requested with @code{@w{#include <@var{file}>}} in:
+
+@example
+/usr/local/include
+/usr/lib/gcc-lib/@var{target}/@var{version}/include
+/usr/@var{target}/include
+/usr/include
+@end example
+
+For C++ programs, it will also look in @file{/usr/include/g++-v3},
+first.  In the above, @var{target} is the canonical name of the system
+GCC was configured to compile code for; often but not always the same as
+the canonical name of the system it runs on.  @var{version} is the
+version of GCC in use.
+
+You can add to this list with the @option{-I@var{dir}} command line
+option.  All the directories named by @option{-I} are searched, in
+left-to-right order, @emph{before} the default directories.  You can
+also prevent GCC from searching any of the default directories with the
+@option{-nostdinc} option.  This is useful when you are compiling an
+operating system kernel or some other program that does not use the
+standard C library facilities, or the standard C library itself.
+
+GCC looks for headers requested with @code{@w{#include "@var{file}"}}
+first in the directory containing the current file, then in the same
+places it would have looked for a header requested with angle brackets.
+For example, if @file{/usr/include/sys/stat.h} contains
+@code{@w{#include "types.h"}}, GCC looks for @file{types.h} first in
+@file{/usr/include/sys}, then in its usual search path.
+
+If you name a search directory with @option{-I@var{dir}} that is also a
+system include directory, the @option{-I} wins; the directory will be
+searched according to the @option{-I} ordering, and it will not be
+treated as a system include directory. GCC will warn you when a system
+include directory is hidden in this way.
+
+@samp{#line} (@pxref{Line Control}) does not change GCC's idea of the
+directory containing the current file.
+
+You may put @option{-I-} at any point in your list of @option{-I} options.
+This has two effects.  First, directories appearing before the
+@option{-I-} in the list are searched only for headers requested with
+quote marks.  Directories after @option{-I-} are searched for all
+headers.  Second, the directory containing the current file is not
+searched for anything, unless it happens to be one of the directories
+named by an @option{-I} switch.
+
+@option{-I. -I-} is not the same as no @option{-I} options at all, and does
+not cause the same behavior for @samp{<>} includes that @samp{""}
+includes get with no special options.  @option{-I.} searches the
+compiler's current working directory for header files.  That may or may
+not be the same as the directory containing the current file.
+
+If you need to look for headers in a directory named @file{-}, write
+@option{-I./-}.
+
+There are several more ways to adjust the header search path.  They are
+generally less useful.  @xref{Invocation}.
+
+@node Once-Only Headers
+@section Once-Only Headers
+@cindex repeated inclusion
+@cindex including just once
+@cindex wrapper @code{#ifndef}
+
+If a header file happens to be included twice, the compiler will process
+its contents twice.  This is very likely to cause an error, e.g.@: when the
+compiler sees the same structure definition twice.  Even if it does not,
+it will certainly waste time.
+
+The standard way to prevent this is to enclose the entire real contents
+of the file in a conditional, like this:
+
+@example
+@group
+/* File foo.  */
+#ifndef FILE_FOO_SEEN
+#define FILE_FOO_SEEN
+
+@var{the entire file}
+
+#endif /* !FILE_FOO_SEEN */
+@end group
+@end example
+
+This construct is commonly known as a @dfn{wrapper #ifndef}.
+When the header is included again, the conditional will be false,
+because @code{FILE_FOO_SEEN} is defined.  The preprocessor will skip
+over the entire contents of the file, and the compiler will not see it
+twice.
+
+GNU CPP optimizes even further.  It remembers when a header file has a
+wrapper @samp{#ifndef}.  If a subsequent @samp{#include} specifies that
+header, and the macro in the @samp{#ifndef} is still defined, it does
+not bother to rescan the file at all.
+
+You can put comments outside the wrapper.  They will not interfere with
+this optimization.
+
+@cindex controlling macro
+@cindex guard macro
+The macro @code{FILE_FOO_SEEN} is called the @dfn{controlling macro} or
+@dfn{guard macro}.  In a user header file, the macro name should not
+begin with @samp{_}.  In a system header file, it should begin with
+@samp{__} to avoid conflicts with user programs.  In any kind of header
+file, the macro name should contain the name of the file and some
+additional text, to avoid conflicts with other header files.
+
+@node Computed Includes
+@section Computed Includes
+@cindex computed includes
+@cindex macros in include
+
+Sometimes it is necessary to select one of several different header
+files to be included into your program.  They might specify
+configuration parameters to be used on different sorts of operating
+systems, for instance.  You could do this with a series of conditionals,
+
+@example
+#if SYSTEM_1
+# include "system_1.h"
+#elif SYSTEM_2
+# include "system_2.h"
+#elif SYSTEM_3
+@dots{}
+#endif
+@end example
+
+That rapidly becomes tedious.  Instead, the preprocessor offers the
+ability to use a macro for the header name.  This is called a
+@dfn{computed include}.  Instead of writing a header name as the direct
+argument of @samp{#include}, you simply put a macro name there instead:
+
+@example
+#define SYSTEM_H "system_1.h"
+@dots{}
+#include SYSTEM_H
+@end example
+
+@noindent
+@code{SYSTEM_H} will be expanded, and the preprocessor will look for
+@file{system_1.h} as if the @samp{#include} had been written that way
+originally.  @code{SYSTEM_H} could be defined by your Makefile with a
+@option{-D} option.
+
+You must be careful when you define the macro.  @samp{#define} saves
+tokens, not text.  The preprocessor has no way of knowing that the macro
+will be used as the argument of @samp{#include}, so it generates
+ordinary tokens, not a header name.  This is unlikely to cause problems
+if you use double-quote includes, which are close enough to string
+constants.  If you use angle brackets, however, you may have trouble.
+
+The syntax of a computed include is actually a bit more general than the
+above.  If the first non-whitespace character after @samp{#include} is
+not @samp{"} or @samp{<}, then the entire line is macro-expanded
+like running text would be.
+
+If the line expands to a single string constant, the contents of that
+string constant are the file to be included.  CPP does not re-examine the
+string for embedded quotes, but neither does it process backslash
+escapes in the string.  Therefore
+
+@example
+#define HEADER "a\"b"
+#include HEADER
+@end example
+
+@noindent
+looks for a file named @file{a\"b}.  CPP searches for the file according
+to the rules for double-quoted includes.
+
+If the line expands to a token stream beginning with a @samp{<} token
+and including a @samp{>} token, then the tokens between the @samp{<} and
+the first @samp{>} are combined to form the filename to be included.
+Any whitespace between tokens is reduced to a single space; then any
+space after the initial @samp{<} is retained, but a trailing space
+before the closing @samp{>} is ignored.  CPP searches for the file
+according to the rules for angle-bracket includes.
+
+In either case, if there are any tokens on the line after the file name,
+an error occurs and the directive is not processed.  It is also an error
+if the result of expansion does not match either of the two expected
+forms.
+
+These rules are implementation-defined behavior according to the C
+standard.  To minimize the risk of different compilers interpreting your
+computed includes differently, we recommend you use only a single
+object-like macro which expands to a string constant.  This will also
+minimize confusion for people reading your program.
+
+@node Wrapper Headers
+@section Wrapper Headers
+@cindex wrapper headers
+@cindex overriding a header file
+@findex #include_next
+
+Sometimes it is necessary to adjust the contents of a system-provided
+header file without editing it directly.  GCC's @command{fixincludes}
+operation does this, for example.  One way to do that would be to create
+a new header file with the same name and insert it in the search path
+before the original header.  That works fine as long as you're willing
+to replace the old header entirely.  But what if you want to refer to
+the old header from the new one?
+
+You cannot simply include the old header with @samp{#include}.  That
+will start from the beginning, and find your new header again.  If your
+header is not protected from multiple inclusion (@pxref{Once-Only
+Headers}), it will recurse infinitely and cause a fatal error.
+
+You could include the old header with an absolute pathname:
+@example
+#include "/usr/include/old-header.h"
+@end example
+@noindent
+This works, but is not clean; should the system headers ever move, you
+would have to edit the new headers to match.
+
+There is no way to solve this problem within the C standard, but you can
+use the GNU extension @samp{#include_next}.  It means, ``Include the
+@emph{next} file with this name.''  This directive works like
+@samp{#include} except in searching for the specified file: it starts
+searching the list of header file directories @emph{after} the directory
+in which the current file was found.
+
+Suppose you specify @option{-I /usr/local/include}, and the list of
+directories to search also includes @file{/usr/include}; and suppose
+both directories contain @file{signal.h}.  Ordinary @code{@w{#include
+<signal.h>}} finds the file under @file{/usr/local/include}.  If that
+file contains @code{@w{#include_next <signal.h>}}, it starts searching
+after that directory, and finds the file in @file{/usr/include}.
+
+@samp{#include_next} does not distinguish between @code{<@var{file}>}
+and @code{"@var{file}"} inclusion, nor does it check that the file you
+specify has the same name as the current file.  It simply looks for the
+file named, starting with the directory in the search path after the one
+where the current file was found.
+
+The use of @samp{#include_next} can lead to great confusion.  We
+recommend it be used only when there is no other alternative.  In
+particular, it should not be used in the headers belonging to a specific
+program; it should be used only to make global corrections along the
+lines of @command{fixincludes}.
+
+@node System Headers
+@section System Headers
+@cindex system header files
+
+The header files declaring interfaces to the operating system and
+runtime libraries often cannot be written in strictly conforming C@.
+Therefore, GCC gives code found in @dfn{system headers} special
+treatment.  All warnings, other than those generated by @samp{#warning}
+(@pxref{Diagnostics}), are suppressed while GCC is processing a system
+header.  Macros defined in a system header are immune to a few warnings
+wherever they are expanded.  This immunity is granted on an ad-hoc
+basis, when we find that a warning generates lots of false positives
+because of code in macros defined in system headers.
+
+Normally, only the headers found in specific directories are considered
+system headers.  These directories are determined when GCC is compiled.
+There are, however, two ways to make normal headers into system headers.
+
+The @option{-isystem} command line option adds its argument to the list of
+directories to search for headers, just like @option{-I}.  Any headers
+found in that directory will be considered system headers.
+
+All directories named by @option{-isystem} are searched @emph{after} all
+directories named by @option{-I}, no matter what their order was on the
+command line.  If the same directory is named by both @option{-I} and
+@option{-isystem}, @option{-I} wins; it is as if the @option{-isystem} option
+had never been specified at all. GCC warns you when this happens.
+
+@findex #pragma GCC system_header
+There is also a directive, @code{@w{#pragma GCC system_header}}, which
+tells GCC to consider the rest of the current include file a system
+header, no matter where it was found.  Code that comes before the
+@samp{#pragma} in the file will not be affected.  @code{@w{#pragma GCC
+system_header}} has no effect in the primary source file.
+
+On very old systems, some of the pre-defined system header directories
+get even more special treatment.  GNU C++ considers code in headers
+found in those directories to be surrounded by an @code{@w{extern "C"}}
+block.  There is no way to request this behavior with a @samp{#pragma},
+or from the command line.
+
+@node Macros
+@chapter Macros
+
+A @dfn{macro} is a fragment of code which has been given a name.
+Whenever the name is used, it is replaced by the contents of the macro.
+There are two kinds of macros.  They differ mostly in what they look
+like when they are used.  @dfn{Object-like} macros resemble data objects
+when used, @dfn{function-like} macros resemble function calls.
+
+You may define any valid identifier as a macro, even if it is a C
+keyword.  The preprocessor does not know anything about keywords.  This
+can be useful if you wish to hide a keyword such as @code{const} from an
+older compiler that does not understand it.  However, the preprocessor
+operator @code{defined} (@pxref{Defined}) can never be defined as a
+macro, and C++'s named operators (@pxref{C++ Named Operators}) cannot be
+macros when you are compiling C++.
+
+@menu
+* Object-like Macros::
+* Function-like Macros::
+* Macro Arguments::
+* Stringification::
+* Concatenation::
+* Variadic Macros::
+* Predefined Macros::
+* Undefining and Redefining Macros::
+* Macro Pitfalls::
+@end menu
+
+@node Object-like Macros
+@section Object-like Macros
+@cindex object-like macro
+@cindex symbolic constants
+@cindex manifest constants
+
+An @dfn{object-like macro} is a simple identifier which will be replaced
+by a code fragment.  It is called object-like because it looks like a
+data object in code that uses it.  They are most commonly used to give
+symbolic names to numeric constants.
+
+@findex #define
+You create macros with the @samp{#define} directive.  @samp{#define} is
+followed by the name of the macro and then the token sequence it should
+be an abbreviation for, which is variously referred to as the macro's
+@dfn{body}, @dfn{expansion} or @dfn{replacement list}.  For example,
+
+@example
+#define BUFFER_SIZE 1024
+@end example
+
+@noindent
+defines a macro named @code{BUFFER_SIZE} as an abbreviation for the
+token @code{1024}.  If somewhere after this @samp{#define} directive
+there comes a C statement of the form
+
+@example
+foo = (char *) malloc (BUFFER_SIZE);
+@end example
+
+@noindent
+then the C preprocessor will recognize and @dfn{expand} the macro
+@code{BUFFER_SIZE}.  The C compiler will see the same tokens as it would
+if you had written
+
+@example
+foo = (char *) malloc (1024);
+@end example
+
+By convention, macro names are written in upper case.  Programs are
+easier to read when it is possible to tell at a glance which names are
+macros.
+
+The macro's body ends at the end of the @samp{#define} line.  You may
+continue the definition onto multiple lines, if necessary, using
+backslash-newline.  When the macro is expanded, however, it will all
+come out on one line.  For example,
+
+@example
+#define NUMBERS 1, \
+                2, \
+                3
+int x[] = @{ NUMBERS @};
+     @expansion{} int x[] = @{ 1, 2, 3 @};
+@end example
+
+@noindent
+The most common visible consequence of this is surprising line numbers
+in error messages.
+
+There is no restriction on what can go in a macro body provided it
+decomposes into valid preprocessing tokens.  Parentheses need not
+balance, and the body need not resemble valid C code.  (If it does not,
+you may get error messages from the C compiler when you use the macro.)
+
+The C preprocessor scans your program sequentially.  Macro definitions
+take effect at the place you write them.  Therefore, the following input
+to the C preprocessor
+
+@example
+foo = X;
+#define X 4
+bar = X;
+@end example
+
+@noindent
+produces
+
+@example
+foo = X;
+bar = 4;
+@end example
+
+When the preprocessor expands a macro name, the macro's expansion
+replaces the macro invocation, then the expansion is examined for more
+macros to expand.  For example,
+
+@example
+@group
+#define TABLESIZE BUFSIZE
+#define BUFSIZE 1024
+TABLESIZE
+     @expansion{} BUFSIZE
+     @expansion{} 1024
+@end group
+@end example
+
+@noindent
+@code{TABLESIZE} is expanded first to produce @code{BUFSIZE}, then that
+macro is expanded to produce the final result, @code{1024}.
+
+Notice that @code{BUFSIZE} was not defined when @code{TABLESIZE} was
+defined.  The @samp{#define} for @code{TABLESIZE} uses exactly the
+expansion you specify---in this case, @code{BUFSIZE}---and does not
+check to see whether it too contains macro names.  Only when you
+@emph{use} @code{TABLESIZE} is the result of its expansion scanned for
+more macro names.
+
+This makes a difference if you change the definition of @code{BUFSIZE}
+at some point in the source file.  @code{TABLESIZE}, defined as shown,
+will always expand using the definition of @code{BUFSIZE} that is
+currently in effect:
+
+@example
+#define BUFSIZE 1020
+#define TABLESIZE BUFSIZE
+#undef BUFSIZE
+#define BUFSIZE 37
+@end example
+
+@noindent
+Now @code{TABLESIZE} expands (in two stages) to @code{37}.
+
+If the expansion of a macro contains its own name, either directly or
+via intermediate macros, it is not expanded again when the expansion is
+examined for more macros.  This prevents infinite recursion.
+@xref{Self-Referential Macros}, for the precise details.
+
+@node Function-like Macros
+@section Function-like Macros
+@cindex function-like macros
+
+You can also define macros whose use looks like a function call.  These
+are called @dfn{function-like macros}.  To define a function-like macro,
+you use the same @samp{#define} directive, but you put a pair of
+parentheses immediately after the macro name.  For example,
+
+@example
+#define lang_init()  c_init()
+lang_init()
+     @expansion{} c_init()
+@end example
+
+A function-like macro is only expanded if its name appears with a pair
+of parentheses after it.  If you write just the name, it is left alone.
+This can be useful when you have a function and a macro of the same
+name, and you wish to use the function sometimes.
+
+@example
+extern void foo(void);
+#define foo() /* optimized inline version */
+@dots{}
+  foo();
+  funcptr = foo;
+@end example
+
+Here the call to @code{foo()} will use the macro, but the function
+pointer will get the address of the real function.  If the macro were to
+be expanded, it would cause a syntax error.
+
+If you put spaces between the macro name and the parentheses in the
+macro definition, that does not define a function-like macro, it defines
+an object-like macro whose expansion happens to begin with a pair of
+parentheses.
+
+@example
+#define lang_init ()    c_init()
+lang_init()
+     @expansion{} () c_init()()
+@end example
+
+The first two pairs of parentheses in this expansion come from the
+macro.  The third is the pair that was originally after the macro
+invocation.  Since @code{lang_init} is an object-like macro, it does not
+consume those parentheses.
+
+@node Macro Arguments
+@section Macro Arguments
+@cindex arguments
+@cindex macros with arguments
+@cindex arguments in macro definitions
+
+Function-like macros can take @dfn{arguments}, just like true functions.
+To define a macro that uses arguments, you insert @dfn{parameters}
+between the pair of parentheses in the macro definition that make the
+macro function-like.  The parameters must be valid C identifiers,
+separated by commas and optionally whitespace.
+
+To invoke a macro that takes arguments, you write the name of the macro
+followed by a list of @dfn{actual arguments} in parentheses, separated
+by commas.  The invocation of the macro need not be restricted to a
+single logical line---it can cross as many lines in the source file as
+you wish.  The number of arguments you give must match the number of
+parameters in the macro definition.  When the macro is expanded, each
+use of a parameter in its body is replaced by the tokens of the
+corresponding argument.  (You need not use all of the parameters in the
+macro body.)
+
+As an example, here is a macro that computes the minimum of two numeric
+values, as it is defined in many C programs, and some uses.
+
+@example
+#define min(X, Y)  ((X) < (Y) ? (X) : (Y))
+  x = min(a, b);          @expansion{}  x = ((a) < (b) ? (a) : (b));
+  y = min(1, 2);          @expansion{}  y = ((1) < (2) ? (1) : (2));
+  z = min(a + 28, *p);    @expansion{}  z = ((a + 28) < (*p) ? (a + 28) : (*p));
+@end example
+
+@noindent
+(In this small example you can already see several of the dangers of
+macro arguments.  @xref{Macro Pitfalls}, for detailed explanations.)
+
+Leading and trailing whitespace in each argument is dropped, and all
+whitespace between the tokens of an argument is reduced to a single
+space.  Parentheses within each argument must balance; a comma within
+such parentheses does not end the argument.  However, there is no
+requirement for square brackets or braces to balance, and they do not
+prevent a comma from separating arguments.  Thus,
+
+@example
+macro (array[x = y, x + 1])
+@end example
+
+@noindent
+passes two arguments to @code{macro}: @code{array[x = y} and @code{x +
+1]}.  If you want to supply @code{array[x = y, x + 1]} as an argument,
+you can write it as @code{array[(x = y, x + 1)]}, which is equivalent C
+code.
+
+All arguments to a macro are completely macro-expanded before they are
+substituted into the macro body.  After substitution, the complete text
+is scanned again for macros to expand, including the arguments.  This rule
+may seem strange, but it is carefully designed so you need not worry
+about whether any function call is actually a macro invocation.  You can
+run into trouble if you try to be too clever, though.  @xref{Argument
+Prescan}, for detailed discussion.
+
+For example, @code{min (min (a, b), c)} is first expanded to
+
+@example
+  min (((a) < (b) ? (a) : (b)), (c))
+@end example
+
+@noindent
+and then to
+
+@example
+@group
+((((a) < (b) ? (a) : (b))) < (c)
+ ? (((a) < (b) ? (a) : (b)))
+ : (c))
+@end group
+@end example
+
+@noindent
+(Line breaks shown here for clarity would not actually be generated.)
+
+@cindex empty macro arguments
+You can leave macro arguments empty; this is not an error to the
+preprocessor (but many macros will then expand to invalid code).
+You cannot leave out arguments entirely; if a macro takes two arguments,
+there must be exactly one comma at the top level of its argument list.
+Here are some silly examples using @code{min}:
+
+@example
+min(, b)        @expansion{} ((   ) < (b) ? (   ) : (b))
+min(a, )        @expansion{} ((a  ) < ( ) ? (a  ) : ( ))
+min(,)          @expansion{} ((   ) < ( ) ? (   ) : ( ))
+min((,),)       @expansion{} (((,)) < ( ) ? ((,)) : ( ))
+
+min()      @error{} macro "min" requires 2 arguments, but only 1 given
+min(,,)    @error{} macro "min" passed 3 arguments, but takes just 2
+@end example
+
+Whitespace is not a preprocessing token, so if a macro @code{foo} takes
+one argument, @code{@w{foo ()}} and @code{@w{foo ( )}} both supply it an
+empty argument.  Previous GNU preprocessor implementations and
+documentation were incorrect on this point, insisting that a
+function-like macro that takes a single argument be passed a space if an
+empty argument was required.
+
+Macro parameters appearing inside string literals are not replaced by
+their corresponding actual arguments.
+
+@example
+#define foo(x) x, "x"
+foo(bar)        @expansion{} bar, "x"
+@end example
+
+@node Stringification
+@section Stringification
+@cindex stringification
+@cindex @samp{#} operator
+
+Sometimes you may want to convert a macro argument into a string
+constant.  Parameters are not replaced inside string constants, but you
+can use the @samp{#} preprocessing operator instead.  When a macro
+parameter is used with a leading @samp{#}, the preprocessor replaces it
+with the literal text of the actual argument, converted to a string
+constant.  Unlike normal parameter replacement, the argument is not
+macro-expanded first.  This is called @dfn{stringification}.
+
+There is no way to combine an argument with surrounding text and
+stringify it all together.  Instead, you can write a series of adjacent
+string constants and stringified arguments.  The preprocessor will
+replace the stringified arguments with string constants.  The C
+compiler will then combine all the adjacent string constants into one
+long string.
+
+Here is an example of a macro definition that uses stringification:
+
+@example
+@group
+#define WARN_IF(EXP) \
+do @{ if (EXP) \
+        fprintf (stderr, "Warning: " #EXP "\n"); @} \
+while (0)
+WARN_IF (x == 0);
+     @expansion{} do @{ if (x == 0)
+           fprintf (stderr, "Warning: " "x == 0" "\n"); @} while (0);
+@end group
+@end example
+
+@noindent
+The argument for @code{EXP} is substituted once, as-is, into the
+@code{if} statement, and once, stringified, into the argument to
+@code{fprintf}.  If @code{x} were a macro, it would be expanded in the
+@code{if} statement, but not in the string.
+
+The @code{do} and @code{while (0)} are a kludge to make it possible to
+write @code{WARN_IF (@var{arg});}, which the resemblance of
+@code{WARN_IF} to a function would make C programmers want to do; see
+@ref{Swallowing the Semicolon}.
+
+Stringification in C involves more than putting double-quote characters
+around the fragment.  The preprocessor backslash-escapes the quotes
+surrounding embedded string constants, and all backslashes within string and
+character constants, in order to get a valid C string constant with the
+proper contents.  Thus, stringifying @code{@w{p = "foo\n";}} results in
+@t{@w{"p = \"foo\\n\";"}}.  However, backslashes that are not inside string
+or character constants are not duplicated: @samp{\n} by itself
+stringifies to @t{"\n"}.
+
+All leading and trailing whitespace in text being stringified is
+ignored.  Any sequence of whitespace in the middle of the text is
+converted to a single space in the stringified result.  Comments are
+replaced by whitespace long before stringification happens, so they
+never appear in stringified text.
+
+There is no way to convert a macro argument into a character constant.
+
+If you want to stringify the result of expansion of a macro argument,
+you have to use two levels of macros.
+
+@example
+#define xstr(s) str(s)
+#define str(s) #s
+#define foo 4
+str (foo)
+     @expansion{} "foo"
+xstr (foo)
+     @expansion{} xstr (4)
+     @expansion{} str (4)
+     @expansion{} "4"
+@end example
+
+@code{s} is stringified when it is used in @code{str}, so it is not
+macro-expanded first.  But @code{s} is an ordinary argument to
+@code{xstr}, so it is completely macro-expanded before @code{xstr}
+itself is expanded (@pxref{Argument Prescan}).  Therefore, by the time
+@code{str} gets to its argument, it has already been macro-expanded.
+
+@node Concatenation
+@section Concatenation
+@cindex concatenation
+@cindex token pasting
+@cindex token concatenation
+@cindex @samp{##} operator
+
+It is often useful to merge two tokens into one while expanding macros.
+This is called @dfn{token pasting} or @dfn{token concatenation}.  The
+@samp{##} preprocessing operator performs token pasting.  When a macro
+is expanded, the two tokens on either side of each @samp{##} operator
+are combined into a single token, which then replaces the @samp{##} and
+the two original tokens in the macro expansion.  Usually both will be
+identifiers, or one will be an identifier and the other a preprocessing
+number.  When pasted, they make a longer identifier.  This isn't the
+only valid case.  It is also possible to concatenate two numbers (or a
+number and a name, such as @code{1.5} and @code{e3}) into a number.
+Also, multi-character operators such as @code{+=} can be formed by
+token pasting.
+
+However, two tokens that don't together form a valid token cannot be
+pasted together.  For example, you cannot concatenate @code{x} with
+@code{+} in either order.  If you try, the preprocessor issues a warning
+and emits the two tokens.  Whether it puts white space between the
+tokens is undefined.  It is common to find unnecessary uses of @samp{##}
+in complex macros.  If you get this warning, it is likely that you can
+simply remove the @samp{##}.
+
+Both the tokens combined by @samp{##} could come from the macro body,
+but you could just as well write them as one token in the first place.
+Token pasting is most useful when one or both of the tokens comes from a
+macro argument.  If either of the tokens next to an @samp{##} is a
+parameter name, it is replaced by its actual argument before @samp{##}
+executes.  As with stringification, the actual argument is not
+macro-expanded first.  If the argument is empty, that @samp{##} has no
+effect.
+
+Keep in mind that the C preprocessor converts comments to whitespace
+before macros are even considered.  Therefore, you cannot create a
+comment by concatenating @samp{/} and @samp{*}.  You can put as much
+whitespace between @samp{##} and its operands as you like, including
+comments, and you can put comments in arguments that will be
+concatenated.  However, it is an error if @samp{##} appears at either
+end of a macro body.
+
+Consider a C program that interprets named commands.  There probably
+needs to be a table of commands, perhaps an array of structures declared
+as follows:
+
+@example
+@group
+struct command
+@{
+  char *name;
+  void (*function) (void);
+@};
+@end group
+
+@group
+struct command commands[] =
+@{
+  @{ "quit", quit_command @},
+  @{ "help", help_command @},
+  @dots{}
+@};
+@end group
+@end example
+
+It would be cleaner not to have to give each command name twice, once in
+the string constant and once in the function name.  A macro which takes the
+name of a command as an argument can make this unnecessary.  The string
+constant can be created with stringification, and the function name by
+concatenating the argument with @samp{_command}.  Here is how it is done:
+
+@example
+#define COMMAND(NAME)  @{ #NAME, NAME ## _command @}
+
+struct command commands[] =
+@{
+  COMMAND (quit),
+  COMMAND (help),
+  @dots{}
+@};
+@end example
+
+@node Variadic Macros
+@section Variadic Macros
+@cindex variable number of arguments
+@cindex macros with variable arguments
+@cindex variadic macros
+
+A macro can be declared to accept a variable number of arguments much as
+a function can.  The syntax for defining the macro is similar to that of
+a function.  Here is an example:
+
+@example
+#define eprintf(@dots{}) fprintf (stderr, __VA_ARGS__)
+@end example
+
+This kind of macro is called @dfn{variadic}.  When the macro is invoked,
+all the tokens in its argument list after the last named argument (this
+macro has none), including any commas, become the @dfn{variable
+argument}.  This sequence of tokens replaces the identifier
+@code{@w{__VA_ARGS__}} in the macro body wherever it appears.  Thus, we
+have this expansion:
+
+@example
+eprintf ("%s:%d: ", input_file, lineno)
+     @expansion{}  fprintf (stderr, "%s:%d: ", input_file, lineno)
+@end example
+
+The variable argument is completely macro-expanded before it is inserted
+into the macro expansion, just like an ordinary argument.  You may use
+the @samp{#} and @samp{##} operators to stringify the variable argument
+or to paste its leading or trailing token with another token.  (But see
+below for an important special case for @samp{##}.)
+
+If your macro is complicated, you may want a more descriptive name for
+the variable argument than @code{@w{__VA_ARGS__}}.  GNU CPP permits
+this, as an extension.  You may write an argument name immediately
+before the @samp{@dots{}}; that name is used for the variable argument.
+The @code{eprintf} macro above could be written
+
+@example
+#define eprintf(args@dots{}) fprintf (stderr, args)
+@end example
+
+@noindent
+using this extension.  You cannot use @code{__VA_ARGS__} and this
+extension in the same macro.
+
+You can have named arguments as well as variable arguments in a variadic
+macro.  We could define @code{eprintf} like this, instead:
+
+@example
+#define eprintf(format, @dots{}) fprintf (stderr, format, __VA_ARGS__)
+@end example
+
+@noindent
+This formulation looks more descriptive, but unfortunately it is less
+flexible: you must now supply at least one argument after the format
+string.  In standard C, you cannot omit the comma separating the named
+argument from the variable arguments.  Furthermore, if you leave the
+variable argument empty, you will get a syntax error, because
+there will be an extra comma after the format string.
+
+@example
+eprintf("success!\n", );
+     @expansion{} fprintf(stderr, "success!\n", );
+@end example
+
+GNU CPP has a pair of extensions which deal with this problem.  First,
+you are allowed to leave the variable argument out entirely:
+
+@example
+eprintf ("success!\n")
+     @expansion{} fprintf(stderr, "success!\n", );
+@end example
+
+@noindent
+Second, the @samp{##} token paste operator has a special meaning when
+placed between a comma and a variable argument.  If you write
+
+@example
+#define eprintf(format, @dots{}) fprintf (stderr, format, ##__VA_ARGS__)
+@end example
+
+@noindent
+and the variable argument is left out when the @code{eprintf} macro is
+used, then the comma before the @samp{##} will be deleted.  This does
+@emph{not} happen if you pass an empty argument, nor does it happen if
+the token preceding @samp{##} is anything other than a comma.
+
+@example
+eprintf ("success!\n")
+     @expansion{} fprintf(stderr, "success!\n");
+@end example
+
+C99 mandates that the only place the identifier @code{@w{__VA_ARGS__}}
+can appear is in the replacement list of a variadic macro.  It may not
+be used as a macro name, macro argument name, or within a different type
+of macro.  It may also be forbidden in open text; the standard is
+ambiguous.  We recommend you avoid using it except for its defined
+purpose.
+
+Variadic macros are a new feature in C99.  GNU CPP has supported them
+for a long time, but only with a named variable argument
+(@samp{args@dots{}}, not @samp{@dots{}} and @code{@w{__VA_ARGS__}}).  If you are
+concerned with portability to previous versions of GCC, you should use
+only named variable arguments.  On the other hand, if you are concerned
+with portability to other conforming implementations of C99, you should
+use only @code{@w{__VA_ARGS__}}.
+
+Previous versions of GNU CPP implemented the comma-deletion extension
+much more generally.  We have restricted it in this release to minimize
+the differences from C99.  To get the same effect with both this and
+previous versions of GCC, the token preceding the special @samp{##} must
+be a comma, and there must be white space between that comma and
+whatever comes immediately before it:
+
+@example
+#define eprintf(format, args@dots{}) fprintf (stderr, format , ##args)
+@end example
+
+@noindent
+@xref{Differences from previous versions}, for the gory details.
+
+@node Predefined Macros
+@section Predefined Macros
+
+@cindex predefined macros
+Several object-like macros are predefined; you use them without
+supplying their definitions.  They fall into three classes: standard,
+common, and system-specific.
+
+In C++, there is a fourth category, the named operators.  They act like
+predefined macros, but you cannot undefine them.
+
+@menu
+* Standard Predefined Macros::
+* Common Predefined Macros::
+* System-specific Predefined Macros::
+* C++ Named Operators::
+@end menu
+
+@node Standard Predefined Macros
+@subsection Standard Predefined Macros
+@cindex standard predefined macros.
+
+The standard predefined macros are specified by the C and/or C++
+language standards, so they are available with all compilers that
+implement those standards.  Older compilers may not provide all of
+them.  Their names all start with double underscores.
+
+@table @code
+@item __FILE__
+This macro expands to the name of the current input file, in the form of
+a C string constant.  This is the path by which the preprocessor opened
+the file, not the short name specified in @samp{#include} or as the
+input file name argument.  For example,
+@code{"/usr/local/include/myheader.h"} is a possible expansion of this
+macro.
+
+@item __LINE__
+This macro expands to the current input line number, in the form of a
+decimal integer constant.  While we call it a predefined macro, it's
+a pretty strange macro, since its ``definition'' changes with each
+new line of source code.
+@end table
+
+@code{__FILE__} and @code{__LINE__} are useful in generating an error
+message to report an inconsistency detected by the program; the message
+can state the source line at which the inconsistency was detected.  For
+example,
+
+@example
+fprintf (stderr, "Internal error: "
+                 "negative string length "
+                 "%d at %s, line %d.",
+         length, __FILE__, __LINE__);
+@end example
+
+An @samp{#include} directive changes the expansions of @code{__FILE__}
+and @code{__LINE__} to correspond to the included file.  At the end of
+that file, when processing resumes on the input file that contained
+the @samp{#include} directive, the expansions of @code{__FILE__} and
+@code{__LINE__} revert to the values they had before the
+@samp{#include} (but @code{__LINE__} is then incremented by one as
+processing moves to the line after the @samp{#include}).
+
+A @samp{#line} directive changes @code{__LINE__}, and may change
+@code{__FILE__} as well.  @xref{Line Control}.
+
+C99 introduces @code{__func__}, and GCC has provided @code{__FUNCTION__}
+for a long time.  Both of these are strings containing the name of the
+current function (there are slight semantic differences; see the GCC
+manual).  Neither of them is a macro; the preprocessor does not know the
+name of the current function.  They tend to be useful in conjunction
+with @code{__FILE__} and @code{__LINE__}, though.
+
+@table @code
+
+@item __DATE__
+This macro expands to a string constant that describes the date on which
+the preprocessor is being run.  The string constant contains eleven
+characters and looks like @code{@w{"Feb 12 1996"}}.  If the day of the
+month is less than 10, it is padded with a space on the left.
+
+@item __TIME__
+This macro expands to a string constant that describes the time at
+which the preprocessor is being run.  The string constant contains
+eight characters and looks like @code{"23:59:01"}.
+
+@item __STDC__
+In normal operation, this macro expands to the constant 1, to signify
+that this compiler conforms to ISO Standard C@.  If GNU CPP is used with
+a compiler other than GCC, this is not necessarily true; however, the
+preprocessor always conforms to the standard, unless the
+@option{-traditional} option is used.
+
+This macro is not defined if the @option{-traditional} option is used.
+
+On some hosts, the system compiler uses a different convention, where
+@code{__STDC__} is normally 0, but is 1 if the user specifies strict
+conformance to the C Standard.  GNU CPP follows the host convention when
+processing system header files, but when processing user files
+@code{__STDC__} is always 1.  This has been reported to cause problems;
+for instance, some versions of Solaris provide X Windows headers that
+expect @code{__STDC__} to be either undefined or 1.  You may be able to
+work around this sort of problem by using an @option{-I} option to
+cancel treatment of those headers as system headers.  @xref{Invocation}.
+
+@item __STDC_VERSION__
+This macro expands to the C Standard's version number, a long integer
+constant of the form @code{@var{yyyy}@var{mm}L} where @var{yyyy} and
+@var{mm} are the year and month of the Standard version.  This signifies
+which version of the C Standard the compiler conforms to.  Like
+@code{__STDC__}, this is not necessarily accurate for the entire
+implementation, unless GNU CPP is being used with GCC@.
+
+The value @code{199409L} signifies the 1989 C standard as amended in
+1994, which is the current default; the value @code{199901L} signifies
+the 1999 revision of the C standard.  Support for the 1999 revision is
+not yet complete.
+
+This macro is not defined if the @option{-traditional} option is used, nor
+when compiling C++ or Objective-C@.
+
+@item __STDC_HOSTED__
+This macro is defined, with value 1, if the compiler's target is a
+@dfn{hosted environment}.  A hosted environment has the complete
+facilities of the standard C library available.
+
+@item __cplusplus
+This macro is defined when the C++ compiler is in use.  You can use
+@code{__cplusplus} to test whether a header is compiled by a C compiler
+or a C++ compiler.  This macro is similar to @code{__STDC_VERSION__}, in
+that it expands to a version number.  A fully conforming implementation
+of the 1998 C++ standard will define this macro to @code{199711L}.  The
+GNU C++ compiler is not yet fully conforming, so it uses @code{1}
+instead.  We hope to complete our implementation in the near future.
+
+@end table
+
+@node Common Predefined Macros
+@subsection Common Predefined Macros
+@cindex common predefined macros
+
+The common predefined macros are GNU C extensions.  They are available
+with the same meanings regardless of the machine or operating system on
+which you are using GNU C@.  Their names all start with double
+underscores.
+
+@table @code
+
+@item __GNUC__
+@itemx __GNUC_MINOR__
+@itemx __GNUC_PATCHLEVEL__
+These macros are defined by all GNU compilers that use the C
+preprocessor: C, C++, and Objective-C@.  Their values are the major
+version, minor version, and patch level of the compiler, as integer
+constants.  For example, GCC 3.2.1 will define @code{__GNUC__} to 3,
+@code{__GNUC_MINOR__} to 2, and @code{__GNUC_PATCHLEVEL__} to 1.  They
+are defined only when the entire compiler is in use; if you invoke the
+preprocessor directly, they are not defined.
+
+@code{__GNUC_PATCHLEVEL__} is new to GCC 3.0; it is also present in the
+widely-used development snapshots leading up to 3.0 (which identify
+themselves as GCC 2.96 or 2.97, depending on which snapshot you have).
+
+If all you need to know is whether or not your program is being compiled
+by GCC, you can simply test @code{__GNUC__}.  If you need to write code
+which depends on a specific version, you must be more careful.  Each
+time the minor version is increased, the patch level is reset to zero;
+each time the major version is increased (which happens rarely), the
+minor version and patch level are reset.  If you wish to use the
+predefined macros directly in the conditional, you will need to write it
+like this:
+
+@example
+/* @r{Test for GCC > 3.2.0} */
+#if __GNUC__ > 3 || \
+    (__GNUC__ == 3 && (__GNUC_MINOR__ > 2 || \
+                       (__GNUC_MINOR__ == 2 && \
+                        __GNUC_PATCHLEVEL__ > 0))
+@end example
+
+@noindent
+Another approach is to use the predefined macros to
+calculate a single number, then compare that against a threshold:
+
+@example
+#define GCC_VERSION (__GNUC__ * 10000 \
+                     + __GNUC_MINOR__ * 100 \
+                     + __GNUC_PATCHLEVEL__)
+@dots{}
+/* @r{Test for GCC > 3.2.0} */
+#if GCC_VERSION > 30200
+@end example
+
+@noindent
+Many people find this form easier to understand.
+
+@item __OBJC__
+This macro is defined, with value 1, when the Objective-C compiler is in
+use.  You can use @code{__OBJC__} to test whether a header is compiled
+by a C compiler or a Objective-C compiler.
+
+@item __GNUG__
+The GNU C++ compiler defines this.  Testing it is equivalent to
+testing @code{@w{(__GNUC__ && __cplusplus)}}.
+
+@item __STRICT_ANSI__
+GCC defines this macro if and only if the @option{-ansi} switch, or a
+@option{-std} switch specifying strict conformance to some version of ISO C,
+was specified when GCC was invoked.  It is defined to @samp{1}.
+This macro exists primarily to direct GNU libc's header files to
+restrict their definitions to the minimal set found in the 1989 C
+standard.
+
+@item __BASE_FILE__
+This macro expands to the name of the main input file, in the form
+of a C string constant.  This is the source file that was specified
+on the command line of the preprocessor or C compiler.
+
+@item __INCLUDE_LEVEL__
+This macro expands to a decimal integer constant that represents the
+depth of nesting in include files.  The value of this macro is
+incremented on every @samp{#include} directive and decremented at the
+end of every included file.  It starts out at 0, it's value within the
+base file specified on the command line.
+
+@item __VERSION__
+This macro expands to a string constant which describes the version of
+the compiler in use.  You should not rely on its contents having any
+particular form, but it can be counted on to contain at least the
+release number.
+
+@item __OPTIMIZE__
+@itemx __OPTIMIZE_SIZE__
+@itemx __NO_INLINE__
+These macros describe the compilation mode.  @code{__OPTIMIZE__} is
+defined in all optimizing compilations.  @code{__OPTIMIZE_SIZE__} is
+defined if the compiler is optimizing for size, not speed.
+@code{__NO_INLINE__} is defined if no functions will be inlined into
+their callers (when not optimizing, or when inlining has been
+specifically disabled by @option{-fno-inline}).
+
+These macros cause certain GNU header files to provide optimized
+definitions, using macros or inline functions, of system library
+functions.  You should not use these macros in any way unless you make
+sure that programs will execute with the same effect whether or not they
+are defined.  If they are defined, their value is 1.
+
+@item __CHAR_UNSIGNED__
+GCC defines this macro if and only if the data type @code{char} is
+unsigned on the target machine.  It exists to cause the standard header
+file @file{limits.h} to work correctly.  You should not use this macro
+yourself; instead, refer to the standard macros defined in @file{limits.h}.
+
+@item __REGISTER_PREFIX__
+This macro expands to a single token (not a string constant) which is
+the prefix applied to CPU register names in assembly language for this
+target.  You can use it to write assembly that is usable in multiple
+environments.  For example, in the @code{m68k-aout} environment it
+expands to nothing, but in the @code{m68k-coff} environment it expands
+to a single @samp{%}.
+
+@item __USER_LABEL_PREFIX__
+This macro expands to a single token which is the prefix applied to
+user labels (symbols visible to C code) in assembly.  For example, in
+the @code{m68k-aout} environment it expands to an @samp{_}, but in the
+@code{m68k-coff} environment it expands to nothing.
+
+This macro will have the correct definition even if
+@option{-f(no-)underscores} is in use, but it will not be correct if
+target-specific options that adjust this prefix are used (e.g.@: the
+OSF/rose @option{-mno-underscores} option).
+
+@item __SIZE_TYPE__
+@itemx __PTRDIFF_TYPE__
+@itemx __WCHAR_TYPE__
+@itemx __WINT_TYPE__
+These macros are defined to the correct underlying types for the
+@code{size_t}, @code{ptrdiff_t}, @code{wchar_t}, and @code{wint_t}
+typedefs, respectively.  They exist to make the standard header files
+@file{stddef.h} and @file{wchar.h} work correctly.  You should not use
+these macros directly; instead, include the appropriate headers and use
+the typedefs.
+
+@item __USING_SJLJ_EXCEPTIONS__
+This macro is defined, with value 1, if the compiler uses the old
+mechanism based on @code{setjmp} and @code{longjmp} for exception
+handling.
+@end table
+
+@node System-specific Predefined Macros
+@subsection System-specific Predefined Macros
+
+@cindex system-specific predefined macros
+@cindex predefined macros, system-specific
+@cindex reserved namespace
+
+The C preprocessor normally predefines several macros that indicate what
+type of system and machine is in use.  They are obviously different on
+each target supported by GCC@.  This manual, being for all systems and
+machines, cannot tell you what their names are, but you can use
+@command{cpp -dM} to see them all.  @xref{Invocation}.  All system-specific
+predefined macros expand to the constant 1, so you can test them with
+either @samp{#ifdef} or @samp{#if}.
+
+The C standard requires that all system-specific macros be part of the
+@dfn{reserved namespace}.  All names which begin with two underscores,
+or an underscore and a capital letter, are reserved for the compiler and
+library to use as they wish.  However, historically system-specific
+macros have had names with no special prefix; for instance, it is common
+to find @code{unix} defined on Unix systems.  For all such macros, GCC
+provides a parallel macro with two underscores added at the beginning
+and the end.  If @code{unix} is defined, @code{__unix__} will be defined
+too.  There will never be more than two underscores; the parallel of
+@code{_mips} is @code{__mips__}.
+
+When the @option{-ansi} option, or any @option{-std} option that
+requests strict conformance, is given to the compiler, all the
+system-specific predefined macros outside the reserved namespace are
+suppressed.  The parallel macros, inside the reserved namespace, remain
+defined.
+
+We are slowly phasing out all predefined macros which are outside the
+reserved namespace.  You should never use them in new programs, and we
+encourage you to correct older code to use the parallel macros whenever
+you find it.  We don't recommend you use the system-specific macros that
+are in the reserved namespace, either.  It is better in the long run to
+check specifically for features you need, using a tool such as
+@command{autoconf}.
+
+@node C++ Named Operators
+@subsection C++ Named Operators
+@cindex named operators
+@cindex C++ named operators
+@cindex iso646.h
+
+In C++, there are eleven keywords which are simply alternate spellings
+of operators normally written with punctuation.  These keywords are
+treated as such even in the preprocessor.  They function as operators in
+@samp{#if}, and they cannot be defined as macros or poisoned.  In C, you
+can request that those keywords take their C++ meaning by including
+@file{iso646.h}.  That header defines each one as a normal object-like
+macro expanding to the appropriate punctuator.
+
+These are the named operators and their corresponding punctuators:
+
+@multitable {Named Operator} {Punctuator}
+@item Named Operator @tab Punctuator
+@item @code{and}    @tab @code{&&}
+@item @code{and_eq} @tab @code{&=}
+@item @code{bitand} @tab @code{&}
+@item @code{bitor}  @tab @code{|}
+@item @code{compl}  @tab @code{~}
+@item @code{not}    @tab @code{!}
+@item @code{not_eq} @tab @code{!=}
+@item @code{or}     @tab @code{||}
+@item @code{or_eq}  @tab @code{|=}
+@item @code{xor}    @tab @code{^}
+@item @code{xor_eq} @tab @code{^=}
+@end multitable
+
+@node Undefining and Redefining Macros
+@section Undefining and Redefining Macros
+@cindex undefining macros
+@cindex redefining macros
+@findex #undef
+
+If a macro ceases to be useful, it may be @dfn{undefined} with the
+@samp{#undef} directive.  @samp{#undef} takes a single argument, the
+name of the macro to undefine.  You use the bare macro name, even if the
+macro is function-like.  It is an error if anything appears on the line
+after the macro name.  @samp{#undef} has no effect if the name is not a
+macro.
+
+@example
+#define FOO 4
+x = FOO;        @expansion{} x = 4;
+#undef FOO
+x = FOO;        @expansion{} x = FOO;
+@end example
+
+Once a macro has been undefined, that identifier may be @dfn{redefined}
+as a macro by a subsequent @samp{#define} directive.  The new definition
+need not have any resemblance to the old definition.
+
+However, if an identifier which is currently a macro is redefined, then
+the new definition must be @dfn{effectively the same} as the old one.
+Two macro definitions are effectively the same if:
+@itemize @bullet
+@item Both are the same type of macro (object- or function-like).
+@item All the tokens of the replacement list are the same.
+@item If there are any parameters, they are the same.
+@item Whitespace appears in the same places in both.  It need not be
+exactly the same amount of whitespace, though.  Remember that comments
+count as whitespace.
+@end itemize
+
+@noindent
+These definitions are effectively the same:
+@example
+#define FOUR (2 + 2)
+#define FOUR         (2    +    2)
+#define FOUR (2 /* two */ + 2)
+@end example
+@noindent
+but these are not:
+@example
+#define FOUR (2 + 2)
+#define FOUR ( 2+2 )
+#define FOUR (2 * 2)
+#define FOUR(score,and,seven,years,ago) (2 + 2)
+@end example
+
+If a macro is redefined with a definition that is not effectively the
+same as the old one, the preprocessor issues a warning and changes the
+macro to use the new definition.  If the new definition is effectively
+the same, the redefinition is silently ignored.  This allows, for
+instance, two different headers to define a common macro.  The
+preprocessor will only complain if the definitions do not match.
+
+@node Macro Pitfalls
+@section Macro Pitfalls
+@cindex problems with macros
+@cindex pitfalls of macros
+
+In this section we describe some special rules that apply to macros and
+macro expansion, and point out certain cases in which the rules have
+counter-intuitive consequences that you must watch out for.
+
+@menu
+* Misnesting::
+* Operator Precedence Problems::
+* Swallowing the Semicolon::
+* Duplication of Side Effects::
+* Self-Referential Macros::
+* Argument Prescan::
+* Newlines in Arguments::
+@end menu
+
+@node Misnesting
+@subsection Misnesting
+
+When a macro is called with arguments, the arguments are substituted
+into the macro body and the result is checked, together with the rest of
+the input file, for more macro calls.  It is possible to piece together
+a macro call coming partially from the macro body and partially from the
+arguments.  For example,
+
+@example
+#define twice(x) (2*(x))
+#define call_with_1(x) x(1)
+call_with_1 (twice)
+     @expansion{} twice(1)
+     @expansion{} (2*(1))
+@end example
+
+Macro definitions do not have to have balanced parentheses.  By writing
+an unbalanced open parenthesis in a macro body, it is possible to create
+a macro call that begins inside the macro body but ends outside of it.
+For example,
+
+@example
+#define strange(file) fprintf (file, "%s %d",
+@dots{}
+strange(stderr) p, 35)
+     @expansion{} fprintf (stderr, "%s %d", p, 35)
+@end example
+
+The ability to piece together a macro call can be useful, but the use of
+unbalanced open parentheses in a macro body is just confusing, and
+should be avoided.
+
+@node Operator Precedence Problems
+@subsection Operator Precedence Problems
+@cindex parentheses in macro bodies
+
+You may have noticed that in most of the macro definition examples shown
+above, each occurrence of a macro argument name had parentheses around
+it.  In addition, another pair of parentheses usually surround the
+entire macro definition.  Here is why it is best to write macros that
+way.
+
+Suppose you define a macro as follows,
+
+@example
+#define ceil_div(x, y) (x + y - 1) / y
+@end example
+
+@noindent
+whose purpose is to divide, rounding up.  (One use for this operation is
+to compute how many @code{int} objects are needed to hold a certain
+number of @code{char} objects.)  Then suppose it is used as follows:
+
+@example
+a = ceil_div (b & c, sizeof (int));
+     @expansion{} a = (b & c + sizeof (int) - 1) / sizeof (int);
+@end example
+
+@noindent
+This does not do what is intended.  The operator-precedence rules of
+C make it equivalent to this:
+
+@example
+a = (b & (c + sizeof (int) - 1)) / sizeof (int);
+@end example
+
+@noindent
+What we want is this:
+
+@example
+a = ((b & c) + sizeof (int) - 1)) / sizeof (int);
+@end example
+
+@noindent
+Defining the macro as
+
+@example
+#define ceil_div(x, y) ((x) + (y) - 1) / (y)
+@end example
+
+@noindent
+provides the desired result.
+
+Unintended grouping can result in another way.  Consider @code{sizeof
+ceil_div(1, 2)}.  That has the appearance of a C expression that would
+compute the size of the type of @code{ceil_div (1, 2)}, but in fact it
+means something very different.  Here is what it expands to:
+
+@example
+sizeof ((1) + (2) - 1) / (2)
+@end example
+
+@noindent
+This would take the size of an integer and divide it by two.  The
+precedence rules have put the division outside the @code{sizeof} when it
+was intended to be inside.
+
+Parentheses around the entire macro definition prevent such problems.
+Here, then, is the recommended way to define @code{ceil_div}:
+
+@example
+#define ceil_div(x, y) (((x) + (y) - 1) / (y))
+@end example
+
+@node Swallowing the Semicolon
+@subsection Swallowing the Semicolon
+@cindex semicolons (after macro calls)
+
+Often it is desirable to define a macro that expands into a compound
+statement.  Consider, for example, the following macro, that advances a
+pointer (the argument @code{p} says where to find it) across whitespace
+characters:
+
+@example
+#define SKIP_SPACES(p, limit)  \
+@{ char *lim = (limit);         \
+  while (p < lim) @{            \
+    if (*p++ != ' ') @{         \
+      p--; break; @}@}@}
+@end example
+
+@noindent
+Here backslash-newline is used to split the macro definition, which must
+be a single logical line, so that it resembles the way such code would
+be laid out if not part of a macro definition.
+
+A call to this macro might be @code{SKIP_SPACES (p, lim)}.  Strictly
+speaking, the call expands to a compound statement, which is a complete
+statement with no need for a semicolon to end it.  However, since it
+looks like a function call, it minimizes confusion if you can use it
+like a function call, writing a semicolon afterward, as in
+@code{SKIP_SPACES (p, lim);}
+
+This can cause trouble before @code{else} statements, because the
+semicolon is actually a null statement.  Suppose you write
+
+@example
+if (*p != 0)
+  SKIP_SPACES (p, lim);
+else @dots{}
+@end example
+
+@noindent
+The presence of two statements---the compound statement and a null
+statement---in between the @code{if} condition and the @code{else}
+makes invalid C code.
+
+The definition of the macro @code{SKIP_SPACES} can be altered to solve
+this problem, using a @code{do @dots{} while} statement.  Here is how:
+
+@example
+#define SKIP_SPACES(p, limit)     \
+do @{ char *lim = (limit);         \
+     while (p < lim) @{            \
+       if (*p++ != ' ') @{         \
+         p--; break; @}@}@}          \
+while (0)
+@end example
+
+Now @code{SKIP_SPACES (p, lim);} expands into
+
+@example
+do @{@dots{}@} while (0);
+@end example
+
+@noindent
+which is one statement.  The loop executes exactly once; most compilers
+generate no extra code for it.
+
+@node Duplication of Side Effects
+@subsection Duplication of Side Effects
+
+@cindex side effects (in macro arguments)
+@cindex unsafe macros
+Many C programs define a macro @code{min}, for ``minimum'', like this:
+
+@example
+#define min(X, Y)  ((X) < (Y) ? (X) : (Y))
+@end example
+
+When you use this macro with an argument containing a side effect,
+as shown here,
+
+@example
+next = min (x + y, foo (z));
+@end example
+
+@noindent
+it expands as follows:
+
+@example
+next = ((x + y) < (foo (z)) ? (x + y) : (foo (z)));
+@end example
+
+@noindent
+where @code{x + y} has been substituted for @code{X} and @code{foo (z)}
+for @code{Y}.
+
+The function @code{foo} is used only once in the statement as it appears
+in the program, but the expression @code{foo (z)} has been substituted
+twice into the macro expansion.  As a result, @code{foo} might be called
+two times when the statement is executed.  If it has side effects or if
+it takes a long time to compute, the results might not be what you
+intended.  We say that @code{min} is an @dfn{unsafe} macro.
+
+The best solution to this problem is to define @code{min} in a way that
+computes the value of @code{foo (z)} only once.  The C language offers
+no standard way to do this, but it can be done with GNU extensions as
+follows:
+
+@example
+#define min(X, Y)                \
+(@{ typeof (X) x_ = (X);          \
+   typeof (Y) y_ = (Y);          \
+   (x_ < y_) ? x_ : y_; @})
+@end example
+
+The @samp{(@{ @dots{} @})} notation produces a compound statement that
+acts as an expression.  Its value is the value of its last statement.
+This permits us to define local variables and assign each argument to
+one.  The local variables have underscores after their names to reduce
+the risk of conflict with an identifier of wider scope (it is impossible
+to avoid this entirely).  Now each argument is evaluated exactly once.
+
+If you do not wish to use GNU C extensions, the only solution is to be
+careful when @emph{using} the macro @code{min}.  For example, you can
+calculate the value of @code{foo (z)}, save it in a variable, and use
+that variable in @code{min}:
+
+@example
+@group
+#define min(X, Y)  ((X) < (Y) ? (X) : (Y))
+@dots{}
+@{
+  int tem = foo (z);
+  next = min (x + y, tem);
+@}
+@end group
+@end example
+
+@noindent
+(where we assume that @code{foo} returns type @code{int}).
+
+@node Self-Referential Macros
+@subsection Self-Referential Macros
+@cindex self-reference
+
+A @dfn{self-referential} macro is one whose name appears in its
+definition.  Recall that all macro definitions are rescanned for more
+macros to replace.  If the self-reference were considered a use of the
+macro, it would produce an infinitely large expansion.  To prevent this,
+the self-reference is not considered a macro call.  It is passed into
+the preprocessor output unchanged.  Let's consider an example:
+
+@example
+#define foo (4 + foo)
+@end example
+
+@noindent
+where @code{foo} is also a variable in your program.
+
+Following the ordinary rules, each reference to @code{foo} will expand
+into @code{(4 + foo)}; then this will be rescanned and will expand into
+@code{(4 + (4 + foo))}; and so on until the computer runs out of memory.
+
+The self-reference rule cuts this process short after one step, at
+@code{(4 + foo)}.  Therefore, this macro definition has the possibly
+useful effect of causing the program to add 4 to the value of @code{foo}
+wherever @code{foo} is referred to.
+
+In most cases, it is a bad idea to take advantage of this feature.  A
+person reading the program who sees that @code{foo} is a variable will
+not expect that it is a macro as well.  The reader will come across the
+identifier @code{foo} in the program and think its value should be that
+of the variable @code{foo}, whereas in fact the value is four greater.
+
+One common, useful use of self-reference is to create a macro which
+expands to itself.  If you write
+
+@example
+#define EPERM EPERM
+@end example
+
+@noindent
+then the macro @code{EPERM} expands to @code{EPERM}.  Effectively, it is
+left alone by the preprocessor whenever it's used in running text.  You
+can tell that it's a macro with @samp{#ifdef}.  You might do this if you
+want to define numeric constants with an @code{enum}, but have
+@samp{#ifdef} be true for each constant.
+
+If a macro @code{x} expands to use a macro @code{y}, and the expansion of
+@code{y} refers to the macro @code{x}, that is an @dfn{indirect
+self-reference} of @code{x}.  @code{x} is not expanded in this case
+either.  Thus, if we have
+
+@example
+#define x (4 + y)
+#define y (2 * x)
+@end example
+
+@noindent
+then @code{x} and @code{y} expand as follows:
+
+@example
+@group
+x    @expansion{} (4 + y)
+     @expansion{} (4 + (2 * x))
+
+y    @expansion{} (2 * x)
+     @expansion{} (2 * (4 + y))
+@end group
+@end example
+
+@noindent
+Each macro is expanded when it appears in the definition of the other
+macro, but not when it indirectly appears in its own definition.
+
+@node Argument Prescan
+@subsection Argument Prescan
+@cindex expansion of arguments
+@cindex macro argument expansion
+@cindex prescan of macro arguments
+
+Macro arguments are completely macro-expanded before they are
+substituted into a macro body, unless they are stringified or pasted
+with other tokens.  After substitution, the entire macro body, including
+the substituted arguments, is scanned again for macros to be expanded.
+The result is that the arguments are scanned @emph{twice} to expand
+macro calls in them.
+
+Most of the time, this has no effect.  If the argument contained any
+macro calls, they are expanded during the first scan.  The result
+therefore contains no macro calls, so the second scan does not change
+it.  If the argument were substituted as given, with no prescan, the
+single remaining scan would find the same macro calls and produce the
+same results.
+
+You might expect the double scan to change the results when a
+self-referential macro is used in an argument of another macro
+(@pxref{Self-Referential Macros}): the self-referential macro would be
+expanded once in the first scan, and a second time in the second scan.
+However, this is not what happens.  The self-references that do not
+expand in the first scan are marked so that they will not expand in the
+second scan either.
+
+You might wonder, ``Why mention the prescan, if it makes no difference?
+And why not skip it and make the preprocessor faster?''  The answer is
+that the prescan does make a difference in three special cases:
+
+@itemize @bullet
+@item
+Nested calls to a macro.
+
+We say that @dfn{nested} calls to a macro occur when a macro's argument
+contains a call to that very macro.  For example, if @code{f} is a macro
+that expects one argument, @code{f (f (1))} is a nested pair of calls to
+@code{f}.  The desired expansion is made by expanding @code{f (1)} and
+substituting that into the definition of @code{f}.  The prescan causes
+the expected result to happen.  Without the prescan, @code{f (1)} itself
+would be substituted as an argument, and the inner use of @code{f} would
+appear during the main scan as an indirect self-reference and would not
+be expanded.
+
+@item
+Macros that call other macros that stringify or concatenate.
+
+If an argument is stringified or concatenated, the prescan does not
+occur.  If you @emph{want} to expand a macro, then stringify or
+concatenate its expansion, you can do that by causing one macro to call
+another macro that does the stringification or concatenation.  For
+instance, if you have
+
+@example
+#define AFTERX(x) X_ ## x
+#define XAFTERX(x) AFTERX(x)
+#define TABLESIZE 1024
+#define BUFSIZE TABLESIZE
+@end example
+
+then @code{AFTERX(BUFSIZE)} expands to @code{X_BUFSIZE}, and
+@code{XAFTERX(BUFSIZE)} expands to @code{X_1024}.  (Not to
+@code{X_TABLESIZE}.  Prescan always does a complete expansion.)
+
+@item
+Macros used in arguments, whose expansions contain unshielded commas.
+
+This can cause a macro expanded on the second scan to be called with the
+wrong number of arguments.  Here is an example:
+
+@example
+#define foo  a,b
+#define bar(x) lose(x)
+#define lose(x) (1 + (x))
+@end example
+
+We would like @code{bar(foo)} to turn into @code{(1 + (foo))}, which
+would then turn into @code{(1 + (a,b))}.  Instead, @code{bar(foo)}
+expands into @code{lose(a,b)}, and you get an error because @code{lose}
+requires a single argument.  In this case, the problem is easily solved
+by the same parentheses that ought to be used to prevent misnesting of
+arithmetic operations:
+
+@example
+#define foo (a,b)
+@exdent or
+#define bar(x) lose((x))
+@end example
+
+The extra pair of parentheses prevents the comma in @code{foo}'s
+definition from being interpreted as an argument separator.
+
+@end itemize
+
+@node Newlines in Arguments
+@subsection Newlines in Arguments
+@cindex newlines in macro arguments
+
+The invocation of a function-like macro can extend over many logical
+lines.  However, in the present implementation, the entire expansion
+comes out on one line.  Thus line numbers emitted by the compiler or
+debugger refer to the line the invocation started on, which might be
+different to the line containing the argument causing the problem.
+
+Here is an example illustrating this:
+
+@example
+#define ignore_second_arg(a,b,c) a; c
+
+ignore_second_arg (foo (),
+                   ignored (),
+                   syntax error);
+@end example
+
+@noindent
+The syntax error triggered by the tokens @code{syntax error} results in
+an error message citing line three---the line of ignore_second_arg---
+even though the problematic code comes from line five.
+
+We consider this a bug, and intend to fix it in the near future.
+
+@node Conditionals
+@chapter Conditionals
+@cindex conditionals
+
+A @dfn{conditional} is a directive that instructs the preprocessor to
+select whether or not to include a chunk of code in the final token
+stream passed to the compiler.  Preprocessor conditionals can test
+arithmetic expressions, or whether a name is defined as a macro, or both
+simultaneously using the special @code{defined} operator.
+
+A conditional in the C preprocessor resembles in some ways an @code{if}
+statement in C, but it is important to understand the difference between
+them.  The condition in an @code{if} statement is tested during the
+execution of your program.  Its purpose is to allow your program to
+behave differently from run to run, depending on the data it is
+operating on.  The condition in a preprocessing conditional directive is
+tested when your program is compiled.  Its purpose is to allow different
+code to be included in the program depending on the situation at the
+time of compilation.
+
+However, the distinction is becoming less clear.  Modern compilers often
+do test @code{if} statements when a program is compiled, if their
+conditions are known not to vary at run time, and eliminate code which
+can never be executed.  If you can count on your compiler to do this,
+you may find that your program is more readable if you use @code{if}
+statements with constant conditions (perhaps determined by macros).  Of
+course, you can only use this to exclude code, not type definitions or
+other preprocessing directives, and you can only do it if the code
+remains syntactically valid when it is not to be used.
+
+GCC version 3 eliminates this kind of never-executed code even when
+not optimizing.  Older versions did it only when optimizing.
+
+@menu
+* Conditional Uses::
+* Conditional Syntax::
+* Deleted Code::
+@end menu
+
+@node Conditional Uses
+@section Conditional Uses
+
+There are three general reasons to use a conditional.
+
+@itemize @bullet
+@item
+A program may need to use different code depending on the machine or
+operating system it is to run on.  In some cases the code for one
+operating system may be erroneous on another operating system; for
+example, it might refer to data types or constants that do not exist on
+the other system.  When this happens, it is not enough to avoid
+executing the invalid code.  Its mere presence will cause the compiler
+to reject the program.  With a preprocessing conditional, the offending
+code can be effectively excised from the program when it is not valid.
+
+@item
+You may want to be able to compile the same source file into two
+different programs.  One version might make frequent time-consuming
+consistency checks on its intermediate data, or print the values of
+those data for debugging, and the other not.
+
+@item
+A conditional whose condition is always false is one way to exclude code
+from the program but keep it as a sort of comment for future reference.
+@end itemize
+
+Simple programs that do not need system-specific logic or complex
+debugging hooks generally will not need to use preprocessing
+conditionals.
+
+@node Conditional Syntax
+@section Conditional Syntax
+
+@findex #if
+A conditional in the C preprocessor begins with a @dfn{conditional
+directive}: @samp{#if}, @samp{#ifdef} or @samp{#ifndef}.
+
+@menu
+* Ifdef::
+* If::
+* Defined::
+* Else::
+* Elif::
+@end menu
+
+@node Ifdef
+@subsection Ifdef
+@findex #ifdef
+@findex #endif
+
+The simplest sort of conditional is
+
+@example
+@group
+#ifdef @var{MACRO}
+
+@var{controlled text}
+
+#endif /* @var{MACRO} */
+@end group
+@end example
+
+@cindex conditional group
+This block is called a @dfn{conditional group}.  @var{controlled text}
+will be included in the output of the preprocessor if and only if
+@var{MACRO} is defined.  We say that the conditional @dfn{succeeds} if
+@var{MACRO} is defined, @dfn{fails} if it is not.
+
+The @var{controlled text} inside of a conditional can include
+preprocessing directives.  They are executed only if the conditional
+succeeds.  You can nest conditional groups inside other conditional
+groups, but they must be completely nested.  In other words,
+@samp{#endif} always matches the nearest @samp{#ifdef} (or
+@samp{#ifndef}, or @samp{#if}).  Also, you cannot start a conditional
+group in one file and end it in another.
+
+Even if a conditional fails, the @var{controlled text} inside it is
+still run through initial transformations and tokenization.  Therefore,
+it must all be lexically valid C@.  Normally the only way this matters is
+that all comments and string literals inside a failing conditional group
+must still be properly ended.
+
+The comment following the @samp{#endif} is not required, but it is a
+good practice if there is a lot of @var{controlled text}, because it
+helps people match the @samp{#endif} to the corresponding @samp{#ifdef}.
+Older programs sometimes put @var{MACRO} directly after the
+@samp{#endif} without enclosing it in a comment.  This is invalid code
+according to the C standard.  GNU CPP accepts it with a warning.  It
+never affects which @samp{#ifndef} the @samp{#endif} matches.
+
+@findex #ifndef
+Sometimes you wish to use some code if a macro is @emph{not} defined.
+You can do this by writing @samp{#ifndef} instead of @samp{#ifdef}.
+One common use of @samp{#ifndef} is to include code only the first
+time a header file is included.  @xref{Once-Only Headers}.
+
+Macro definitions can vary between compilations for several reasons.
+Here are some samples.
+
+@itemize @bullet
+@item
+Some macros are predefined on each kind of machine
+(@pxref{System-specific Predefined Macros}).  This allows you to provide
+code specially tuned for a particular machine.
+
+@item
+System header files define more macros, associated with the features
+they implement.  You can test these macros with conditionals to avoid
+using a system feature on a machine where it is not implemented.
+
+@item
+Macros can be defined or undefined with the @option{-D} and @option{-U}
+command line options when you compile the program.  You can arrange to
+compile the same source file into two different programs by choosing a
+macro name to specify which program you want, writing conditionals to
+test whether or how this macro is defined, and then controlling the
+state of the macro with command line options, perhaps set in the
+Makefile.  @xref{Invocation}.
+
+@item
+Your program might have a special header file (often called
+@file{config.h}) that is adjusted when the program is compiled.  It can
+define or not define macros depending on the features of the system and
+the desired capabilities of the program.  The adjustment can be
+automated by a tool such as @command{autoconf}, or done by hand.
+@end itemize
+
+@node If
+@subsection If
+
+The @samp{#if} directive allows you to test the value of an arithmetic
+expression, rather than the mere existence of one macro.  Its syntax is
+
+@example
+@group
+#if @var{expression}
+
+@var{controlled text}
+
+#endif /* @var{expression} */
+@end group
+@end example
+
+@var{expression} is a C expression of integer type, subject to stringent
+restrictions.  It may contain
+
+@itemize @bullet
+@item
+Integer constants.
+
+@item
+Character constants, which are interpreted as they would be in normal
+code.
+
+@item
+Arithmetic operators for addition, subtraction, multiplication,
+division, bitwise operations, shifts, comparisons, and logical
+operations (@code{&&} and @code{||}).  The latter two obey the usual
+short-circuiting rules of standard C@.
+
+@item
+Macros.  All macros in the expression are expanded before actual
+computation of the expression's value begins.
+
+@item
+Uses of the @code{defined} operator, which lets you check whether macros
+are defined in the middle of an @samp{#if}.
+
+@item
+Identifiers that are not macros, which are all considered to be the
+number zero.  This allows you to write @code{@w{#if MACRO}} instead of
+@code{@w{#ifdef MACRO}}, if you know that MACRO, when defined, will
+always have a nonzero value.  Function-like macros used without their
+function call parentheses are also treated as zero.
+
+In some contexts this shortcut is undesirable.  The @option{-Wundef}
+option causes GCC to warn whenever it encounters an identifier which is
+not a macro in an @samp{#if}.
+@end itemize
+
+The preprocessor does not know anything about types in the language.
+Therefore, @code{sizeof} operators are not recognized in @samp{#if}, and
+neither are @code{enum} constants.  They will be taken as identifiers
+which are not macros, and replaced by zero.  In the case of
+@code{sizeof}, this is likely to cause the expression to be invalid.
+
+The preprocessor calculates the value of @var{expression}.  It carries
+out all calculations in the widest integer type known to the compiler;
+on most machines supported by GCC this is 64 bits.  This is not the same
+rule as the compiler uses to calculate the value of a constant
+expression, and may give different results in some cases.  If the value
+comes out to be nonzero, the @samp{#if} succeeds and the @var{controlled
+text} is included; otherwise it is skipped.
+
+If @var{expression} is not correctly formed, GCC issues an error and
+treats the conditional as having failed.
+
+@node Defined
+@subsection Defined
+
+@cindex @code{defined}
+The special operator @code{defined} is used in @samp{#if} and
+@samp{#elif} expressions to test whether a certain name is defined as a
+macro.  @code{defined @var{name}} and @code{defined (@var{name})} are
+both expressions whose value is 1 if @var{name} is defined as a macro at
+the current point in the program, and 0 otherwise.  Thus,  @code{@w{#if
+defined MACRO}} is precisely equivalent to @code{@w{#ifdef MACRO}}.
+
+@code{defined} is useful when you wish to test more than one macro for
+existence at once.  For example,
+
+@example
+#if defined (__vax__) || defined (__ns16000__)
+@end example
+
+@noindent
+would succeed if either of the names @code{__vax__} or
+@code{__ns16000__} is defined as a macro.
+
+Conditionals written like this:
+
+@example
+#if defined BUFSIZE && BUFSIZE >= 1024
+@end example
+
+@noindent
+can generally be simplified to just @code{@w{#if BUFSIZE >= 1024}},
+since if @code{BUFSIZE} is not defined, it will be interpreted as having
+the value zero.
+
+If the @code{defined} operator appears as a result of a macro expansion,
+the C standard says the behavior is undefined.  GNU cpp treats it as a
+genuine @code{defined} operator and evaluates it normally.  It will warn
+wherever your code uses this feature if you use the command-line option
+@option{-pedantic}, since other compilers may handle it differently.
+
+@node Else
+@subsection Else
+
+@findex #else
+The @samp{#else} directive can be added to a conditional to provide
+alternative text to be used if the condition fails.  This is what it
+looks like:
+
+@example
+@group
+#if @var{expression}
+@var{text-if-true}
+#else /* Not @var{expression} */
+@var{text-if-false}
+#endif /* Not @var{expression} */
+@end group
+@end example
+
+@noindent
+If @var{expression} is nonzero, the @var{text-if-true} is included and
+the @var{text-if-false} is skipped.  If @var{expression} is zero, the
+opposite happens.
+
+You can use @samp{#else} with @samp{#ifdef} and @samp{#ifndef}, too.
+
+@node Elif
+@subsection Elif
+
+@findex #elif
+One common case of nested conditionals is used to check for more than two
+possible alternatives.  For example, you might have
+
+@example
+#if X == 1
+@dots{}
+#else /* X != 1 */
+#if X == 2
+@dots{}
+#else /* X != 2 */
+@dots{}
+#endif /* X != 2 */
+#endif /* X != 1 */
+@end example
+
+Another conditional directive, @samp{#elif}, allows this to be
+abbreviated as follows:
+
+@example
+#if X == 1
+@dots{}
+#elif X == 2
+@dots{}
+#else /* X != 2 and X != 1*/
+@dots{}
+#endif /* X != 2 and X != 1*/
+@end example
+
+@samp{#elif} stands for ``else if''.  Like @samp{#else}, it goes in the
+middle of a conditional group and subdivides it; it does not require a
+matching @samp{#endif} of its own.  Like @samp{#if}, the @samp{#elif}
+directive includes an expression to be tested.  The text following the
+@samp{#elif} is processed only if the original @samp{#if}-condition
+failed and the @samp{#elif} condition succeeds.
+
+More than one @samp{#elif} can go in the same conditional group.  Then
+the text after each @samp{#elif} is processed only if the @samp{#elif}
+condition succeeds after the original @samp{#if} and all previous
+@samp{#elif} directives within it have failed.
+
+@samp{#else} is allowed after any number of @samp{#elif} directives, but
+@samp{#elif} may not follow @samp{#else}.
+
+@node Deleted Code
+@section Deleted Code
+@cindex commenting out code
+
+If you replace or delete a part of the program but want to keep the old
+code around for future reference, you often cannot simply comment it
+out.  Block comments do not nest, so the first comment inside the old
+code will end the commenting-out.  The probable result is a flood of
+syntax errors.
+
+One way to avoid this problem is to use an always-false conditional
+instead.  For instance, put @code{#if 0} before the deleted code and
+@code{#endif} after it.  This works even if the code being turned
+off contains conditionals, but they must be entire conditionals
+(balanced @samp{#if} and @samp{#endif}).
+
+Some people use @code{#ifdef notdef} instead.  This is risky, because
+@code{notdef} might be accidentally defined as a macro, and then the
+conditional would succeed.  @code{#if 0} can be counted on to fail.
+
+Do not use @code{#if 0} for comments which are not C code.  Use a real
+comment, instead.  The interior of @code{#if 0} must consist of complete
+tokens; in particular, single-quote characters must balance.  Comments
+often contain unbalanced single-quote characters (known in English as
+apostrophes).  These confuse @code{#if 0}.  They don't confuse
+@samp{/*}.
+
+@node Diagnostics
+@chapter Diagnostics
+@cindex diagnostic
+@cindex reporting errors
+@cindex reporting warnings
+
+@findex #error
+The directive @samp{#error} causes the preprocessor to report a fatal
+error.  The tokens forming the rest of the line following @samp{#error}
+are used as the error message.
+
+You would use @samp{#error} inside of a conditional that detects a
+combination of parameters which you know the program does not properly
+support.  For example, if you know that the program will not run
+properly on a VAX, you might write
+
+@example
+@group
+#ifdef __vax__
+#error "Won't work on VAXen.  See comments at get_last_object."
+#endif
+@end group
+@end example
+
+If you have several configuration parameters that must be set up by
+the installation in a consistent way, you can use conditionals to detect
+an inconsistency and report it with @samp{#error}.  For example,
+
+@example
+#if !defined(UNALIGNED_INT_ASM_OP) && defined(DWARF2_DEBUGGING_INFO)
+#error "DWARF2_DEBUGGING_INFO requires UNALIGNED_INT_ASM_OP."
+#endif
+@end example
+
+@findex #warning
+The directive @samp{#warning} is like @samp{#error}, but causes the
+preprocessor to issue a warning and continue preprocessing.  The tokens
+following @samp{#warning} are used as the warning message.
+
+You might use @samp{#warning} in obsolete header files, with a message
+directing the user to the header file which should be used instead.
+
+Neither @samp{#error} nor @samp{#warning} macro-expands its argument.
+Internal whitespace sequences are each replaced with a single space.
+The line must consist of complete tokens.  It is wisest to make the
+argument of these directives be a single string constant; this avoids
+problems with apostrophes and the like.
+
+@node Line Control
+@chapter Line Control
+@cindex line control
+
+The C preprocessor informs the C compiler of the location in your source
+code where each token came from.  Presently, this is just the file name
+and line number.  All the tokens resulting from macro expansion are
+reported as having appeared on the line of the source file where the
+outermost macro was used.  We intend to be more accurate in the future.
+
+If you write a program which generates source code, such as the
+@command{bison} parser generator, you may want to adjust the preprocessor's
+notion of the current file name and line number by hand.  Parts of the
+output from @command{bison} are generated from scratch, other parts come
+from a standard parser file.  The rest are copied verbatim from
+@command{bison}'s input.  You would like compiler error messages and
+symbolic debuggers to be able to refer to @code{bison}'s input file.
+
+@findex #line
+@command{bison} or any such program can arrange this by writing
+@samp{#line} directives into the output file.  @samp{#line} is a
+directive that specifies the original line number and source file name
+for subsequent input in the current preprocessor input file.
+@samp{#line} has three variants:
+
+@table @code
+@item #line @var{linenum}
+@var{linenum} is a non-negative decimal integer constant.  It specifies
+the line number which should be reported for the following line of
+input.  Subsequent lines are counted from @var{linenum}.
+
+@item #line @var{linenum} @var{filename}
+@var{linenum} is the same as for the first form, and has the same
+effect.  In addition, @var{filename} is a string constant.  The
+following line and all subsequent lines are reported to come from the
+file it specifies, until something else happens to change that.
+
+@item #line @var{anything else}
+@var{anything else} is checked for macro calls, which are expanded.
+The result should match one of the above two forms.
+@end table
+
+@samp{#line} directives alter the results of the @code{__FILE__} and
+@code{__LINE__} predefined macros from that point on.  @xref{Standard
+Predefined Macros}.  They do not have any effect on @samp{#include}'s
+idea of the directory containing the current file.
+
+@node Pragmas
+@chapter Pragmas
+
+The @samp{#pragma} directive is the method specified by the C standard
+for providing additional information to the compiler, beyond what is
+conveyed in the language itself.  Three forms of this directive
+(commonly known as @dfn{pragmas}) are specified by the 1999 C standard.
+A C compiler is free to attach any meaning it likes to other pragmas.
+
+GCC has historically preferred to use extensions to the syntax of the
+language, such as @code{__attribute__}, for this purpose.  However, GCC
+does define a few pragmas of its own.  These mostly have effects on the
+entire translation unit or source file.
+
+In GCC version 3, all GNU-defined, supported pragmas have been given a
+@code{GCC} prefix.  This is in line with the @code{STDC} prefix on all
+pragmas defined by C99.  For backward compatibility, pragmas which were
+recognized by previous versions are still recognized without the
+@code{GCC} prefix, but that usage is deprecated.  Some older pragmas are
+deprecated in their entirety.  They are not recognized with the
+@code{GCC} prefix.  @xref{Obsolete Features}.
+
+@cindex @code{_Pragma}
+C99 introduces the @code{@w{_Pragma}} operator.  This feature addresses a
+major problem with @samp{#pragma}: being a directive, it cannot be
+produced as the result of macro expansion.  @code{@w{_Pragma}} is an
+operator, much like @code{sizeof} or @code{defined}, and can be embedded
+in a macro.
+
+Its syntax is @code{@w{_Pragma (@var{string-literal})}}, where
+@var{string-literal} can be either a normal or wide-character string
+literal.  It is destringized, by replacing all @samp{\\} with a single
+@samp{\} and all @samp{\"} with a @samp{"}.  The result is then
+processed as if it had appeared as the right hand side of a
+@samp{#pragma} directive.  For example,
+
+@example
+_Pragma ("GCC dependency \"parse.y\"")
+@end example
+
+@noindent
+has the same effect as @code{#pragma GCC dependency "parse.y"}.  The
+same effect could be achieved using macros, for example
+
+@example
+#define DO_PRAGMA(x) _Pragma (#x)
+DO_PRAGMA (GCC dependency "parse.y")
+@end example
+
+The standard is unclear on where a @code{_Pragma} operator can appear.
+The preprocessor does not accept it within a preprocessing conditional
+directive like @samp{#if}.  To be safe, you are probably best keeping it
+out of directives other than @samp{#define}, and putting it on a line of
+its own.
+
+This manual documents the pragmas which are meaningful to the
+preprocessor itself.  Other pragmas are meaningful to the C or C++
+compilers.  They are documented in the GCC manual.
+
+@ftable @code
+@item #pragma GCC dependency
+@code{#pragma GCC dependency} allows you to check the relative dates of
+the current file and another file.  If the other file is more recent than
+the current file, a warning is issued.  This is useful if the current
+file is derived from the other file, and should be regenerated.  The
+other file is searched for using the normal include search path.
+Optional trailing text can be used to give more information in the
+warning message.
+
+@example
+#pragma GCC dependency "parse.y"
+#pragma GCC dependency "/usr/include/time.h" rerun fixincludes
+@end example
+
+@item #pragma GCC poison
+Sometimes, there is an identifier that you want to remove completely
+from your program, and make sure that it never creeps back in.  To
+enforce this, you can @dfn{poison} the identifier with this pragma.
+@code{#pragma GCC poison} is followed by a list of identifiers to
+poison.  If any of those identifiers appears anywhere in the source
+after the directive, it is a hard error.  For example,
+
+@example
+#pragma GCC poison printf sprintf fprintf
+sprintf(some_string, "hello");
+@end example
+
+@noindent
+will produce an error.
+
+If a poisoned identifier appears as part of the expansion of a macro
+which was defined before the identifier was poisoned, it will @emph{not}
+cause an error.  This lets you poison an identifier without worrying
+about system headers defining macros that use it.
+
+For example,
+
+@example
+#define strrchr rindex
+#pragma GCC poison rindex
+strrchr(some_string, 'h');
+@end example
+
+@noindent
+will not produce an error.
+
+@item #pragma GCC system_header
+This pragma takes no arguments.  It causes the rest of the code in the
+current file to be treated as if it came from a system header.
+@xref{System Headers}.
+
+@end ftable
+
+@node Other Directives
+@chapter Other Directives
+
+@findex #ident
+The @samp{#ident} directive takes one argument, a string constant.  On
+some systems, that string constant is copied into a special segment of
+the object file.  On other systems, the directive is ignored.
+
+This directive is not part of the C standard, but it is not an official
+GNU extension either.  We believe it came from System V@.
+
+@findex #sccs
+The @samp{#sccs} directive is recognized on some systems, because it
+appears in their header files.  It is a very old, obscure, extension
+which we did not invent, and we have been unable to find any
+documentation of what it should do, so GCC simply ignores it.
+
+@cindex null directive
+The @dfn{null directive} consists of a @samp{#} followed by a newline,
+with only whitespace (including comments) in between.  A null directive
+is understood as a preprocessing directive but has no effect on the
+preprocessor output.  The primary significance of the existence of the
+null directive is that an input line consisting of just a @samp{#} will
+produce no output, rather than a line of output containing just a
+@samp{#}.  Supposedly some old C programs contain such lines.
+
+@node Preprocessor Output
+@chapter Preprocessor Output
+
+When the C preprocessor is used with the C, C++, or Objective-C
+compilers, it is integrated into the compiler and communicates a stream
+of binary tokens directly to the compiler's parser.  However, it can
+also be used in the more conventional standalone mode, where it produces
+textual output.
+@c FIXME: Document the library interface.
+
+@cindex output format
+The output from the C preprocessor looks much like the input, except
+that all preprocessing directive lines have been replaced with blank
+lines and all comments with spaces.  Long runs of blank lines are
+discarded.
+
+The ISO standard specifies that it is implementation defined whether a
+preprocessor preserves whitespace between tokens, or replaces it with
+e.g.@: a single space.  In GNU CPP, whitespace between tokens is collapsed
+to become a single space, with the exception that the first token on a
+non-directive line is preceded with sufficient spaces that it appears in
+the same column in the preprocessed output that it appeared in the
+original source file.  This is so the output is easy to read.
+@xref{Differences from previous versions}.  CPP does not insert any
+whitespace where there was none in the original source, except where
+necessary to prevent an accidental token paste.
+
+@cindex linemarkers
+Source file name and line number information is conveyed by lines
+of the form
+
+@example
+# @var{linenum} @var{filename} @var{flags}
+@end example
+
+@noindent
+These are called @dfn{linemarkers}.  They are inserted as needed into
+the output (but never within a string or character constant).  They mean
+that the following line originated in file @var{filename} at line
+@var{linenum}.
+
+After the file name comes zero or more flags, which are @samp{1},
+@samp{2}, @samp{3}, or @samp{4}.  If there are multiple flags, spaces
+separate them.  Here is what the flags mean:
+
+@table @samp
+@item 1
+This indicates the start of a new file.
+@item 2
+This indicates returning to a file (after having included another file).
+@item 3
+This indicates that the following text comes from a system header file,
+so certain warnings should be suppressed.
+@item 4
+This indicates that the following text should be treated as being
+wrapped in an implicit @code{extern "C"} block.
+@c maybe cross reference NO_IMPLICIT_EXTERN_C
+@end table
+
+As an extension, the preprocessor accepts linemarkers in non-assembler
+input files.  They are treated like the corresponding @samp{#line}
+directive, (@pxref{Line Control}), except that trailing flags are
+permitted, and are interpreted with the meanings described above.  If
+multiple flags are given, they must be in ascending order.
+
+Some directives may be duplicated in the output of the preprocessor.
+These are @samp{#ident} (always), @samp{#pragma} (only if the
+preprocessor does not handle the pragma itself), and @samp{#define} and
+@samp{#undef} (with certain debugging options).  If this happens, the
+@samp{#} of the directive will always be in the first column, and there
+will be no space between the @samp{#} and the directive name.  If macro
+expansion happens to generate tokens which might be mistaken for a
+duplicated directive, a space will be inserted between the @samp{#} and
+the directive name.
+
+@node Traditional Mode
+@chapter Traditional Mode
+
+Traditional (pre-standard) C preprocessing is rather different from
+the preprocessing specified by the standard.  When GCC is given the
+@option{-traditional} option, it attempts to emulate a traditional
+preprocessor.  We do not guarantee that GCC's behavior under
+@option{-traditional} matches any pre-standard preprocessor exactly.
+
+Traditional mode exists only for backward compatibility.  We have no
+plans to augment it in any way nor will we change it except to fix
+catastrophic bugs.  You should be aware that modern C libraries often
+have header files which are incompatible with traditional mode.
+
+This is a list of the differences.  It may not be complete, and may not
+correspond exactly to the behavior of either GCC or a true traditional
+preprocessor.
+
+@itemize @bullet
+@item
+Traditional macro expansion pays no attention to single-quote or
+double-quote characters; macro argument symbols are replaced by the
+argument values even when they appear within apparent string or
+character constants.
+
+@item
+Traditionally, it is permissible for a macro expansion to end in the
+middle of a string or character constant.  The constant continues into
+the text surrounding the macro call.
+
+@item
+However, the end of the line terminates a string or character constant,
+with no error.  (This is a kluge.  Traditional mode is commonly used to
+preprocess things which are not C, and have a different comment syntax.
+Single apostrophes often appear in comments.  This kluge prevents the
+traditional preprocessor from issuing errors on such comments.)
+
+@item
+Preprocessing directives are recognized in traditional C only when their
+leading @samp{#} appears in the first column.  There can be no
+whitespace between the beginning of the line and the @samp{#}.
+
+@item
+In traditional C, a comment is equivalent to no text at all.  (In ISO
+C, a comment counts as whitespace.)  It can be used sort of the same way
+that @samp{##} is used in ISO C, to paste macro arguments together.
+
+@item
+Traditional C does not have the concept of a preprocessing number.
+
+@item
+A macro is not suppressed within its own definition, in traditional C@.
+Thus, any macro that is used recursively inevitably causes an error.
+
+@item
+The @samp{#} and @samp{##} operators are not available in traditional
+C@.
+
+@item
+In traditional C, the text at the end of a macro expansion can run
+together with the text after the macro call, to produce a single token.
+This is impossible in ISO C@.
+
+@item
+None of the GNU extensions to the preprocessor are available in
+traditional mode, with the exception of a partial implementation of
+assertions, and those may be removed in the future.
+
+@item
+A true traditional C preprocessor does not recognize @samp{#elif},
+@samp{#error}, or @samp{#pragma}.  GCC supports @samp{#elif} and
+@samp{#error} even in traditional mode, but not @samp{#pragma}.
+
+@item
+Traditional mode is text-based, not token-based, and comments are
+stripped after macro expansion.  Therefore, @samp{/**/} can be used to
+paste tokens together provided that there is no whitespace between it
+and the tokens to be pasted.
+
+@item
+Traditional mode preserves the amount and form of whitespace provided by
+the user.  Hard tabs remain hard tabs.  This can be useful, e.g.@: if you
+are preprocessing a Makefile (which we do not encourage).
+@end itemize
+
+You can request warnings about features that did not exist, or worked
+differently, in traditional C with the @option{-Wtraditional} option.
+This works only if you do @emph{not} specify @option{-traditional}.  GCC
+does not warn about features of ISO C which you must use when you are
+using a conforming compiler, such as the @samp{#} and @samp{##}
+operators.
+
+Presently @option{-Wtraditional} warns about:
+
+@itemize @bullet
+@item
+Macro parameters that appear within string literals in the macro body.
+In traditional C macro replacement takes place within string literals,
+but does not in ISO C@.
+
+@item
+In traditional C, some preprocessor directives did not exist.
+Traditional preprocessors would only consider a line to be a directive
+if the @samp{#} appeared in column 1 on the line.  Therefore
+@option{-Wtraditional} warns about directives that traditional C
+understands but would ignore because the @samp{#} does not appear as the
+first character on the line.  It also suggests you hide directives like
+@samp{#pragma} not understood by traditional C by indenting them.  Some
+traditional implementations would not recognize @samp{#elif}, so it
+suggests avoiding it altogether.
+
+@item
+A function-like macro that appears without an argument list.  In
+traditional C this was an error.  In ISO C it merely means that the
+macro is not expanded.
+
+@item
+The unary plus operator.  This did not exist in traditional C@.
+
+@item
+The @samp{U} and @samp{LL} integer constant suffixes, which were not
+available in traditional C@.  (Traditional C does support the @samp{L}
+suffix for simple long integer constants.)  You are not warned about
+uses of these suffixes in macros defined in system headers.  For
+instance, @code{UINT_MAX} may well be defined as @code{4294967295U}, but
+you will not be warned if you use @code{UINT_MAX}.
+
+You can usually avoid the warning, and the related warning about
+constants which are so large that they are unsigned, by writing the
+integer constant in question in hexadecimal, with no U suffix.  Take
+care, though, because this gives the wrong result in exotic cases.
+@end itemize
+
+@node Implementation Details
+@chapter Implementation Details
+
+Here we document details of how the preprocessor's implementation
+affects its user-visible behavior.  You should try to avoid undue
+reliance on behavior described here, as it is possible that it will
+change subtly in future implementations.
+
+Also documented here are obsolete features and changes from previous
+versions of GNU CPP@.
+
+@menu
+* Implementation-defined behavior::
+* Implementation limits::
+* Obsolete Features::
+* Differences from previous versions::
+@end menu
+
+@node Implementation-defined behavior
+@section Implementation-defined behavior
+@cindex implementation-defined behavior
+
+This is how GNU CPP behaves in all the cases which the C standard
+describes as @dfn{implementation-defined}.  This term means that the
+implementation is free to do what it likes, but must document its choice
+and stick to it.
+@c FIXME: Check the C++ standard for more implementation-defined stuff.
+
+@itemize @bullet
+@need 1000
+@item The mapping of physical source file multi-byte characters to the
+execution character set.
+
+Currently, GNU cpp only supports character sets that are strict supersets
+of ASCII, and performs no translation of characters.
+
+@item Non-empty sequences of whitespace characters.
+
+In textual output, each whitespace sequence is collapsed to a single
+space.  For aesthetic reasons, the first token on each non-directive
+line of output is preceded with sufficient spaces that it appears in the
+same column as it did in the original source file.
+
+@item The numeric value of character constants in preprocessor expressions.
+
+The preprocessor and compiler interpret character constants in the same
+way; escape sequences such as @samp{\a} are given the values they would
+have on the target machine.
+
+Multi-character character constants are interpreted a character at a
+time, shifting the previous result left by the number of bits per
+character on the host, and adding the new character.  For example, 'ab'
+on an 8-bit host would be interpreted as @w{'a' * 256 + 'b'}.  If there
+are more characters in the constant than can fit in the widest native
+integer type on the host, usually a @code{long}, the excess characters
+are ignored and a diagnostic is given.
+
+@item Source file inclusion.
+
+For a discussion on how the preprocessor locates header files,
+@ref{Include Operation}.
+
+@item Interpretation of the filename resulting from a macro-expanded
+@samp{#include} directive.
+
+@xref{Computed Includes}.
+
+@item Treatment of a @samp{#pragma} directive that after macro-expansion
+results in a standard pragma.
+
+No macro expansion occurs on any @samp{#pragma} directive line, so the
+question does not arise.
+
+Note that GCC does not yet implement any of the standard
+pragmas.
+
+@end itemize
+
+@node Implementation limits
+@section Implementation limits
+@cindex implementation limits
+
+GNU CPP has a small number of internal limits.  This section lists the
+limits which the C standard requires to be no lower than some minimum,
+and all the others we are aware of.  We intend there to be as few limits
+as possible.  If you encounter an undocumented or inconvenient limit,
+please report that to us as a bug.  (See the section on reporting bugs in
+the GCC manual.)
+
+Where we say something is limited @dfn{only by available memory}, that
+means that internal data structures impose no intrinsic limit, and space
+is allocated with @code{malloc} or equivalent.  The actual limit will
+therefore depend on many things, such as the size of other things
+allocated by the compiler at the same time, the amount of memory
+consumed by other processes on the same computer, etc.
+
+@itemize @bullet
+
+@item Nesting levels of @samp{#include} files.
+
+We impose an arbitrary limit of 200 levels, to avoid runaway recursion.
+The standard requires at least 15 levels.
+
+@item Nesting levels of conditional inclusion.
+
+The C standard mandates this be at least 63.  GNU CPP is limited only by
+available memory.
+
+@item Levels of parenthesised expressions within a full expression.
+
+The C standard requires this to be at least 63.  In preprocessor
+conditional expressions, it is limited only by available memory.
+
+@item Significant initial characters in an identifier or macro name.
+
+The preprocessor treats all characters as significant.  The C standard
+requires only that the first 63 be significant.
+
+@item Number of macros simultaneously defined in a single translation unit.
+
+The standard requires at least 4095 be possible.  GNU CPP is limited only
+by available memory.
+
+@item Number of parameters in a macro definition and arguments in a macro call.
+
+We allow @code{USHRT_MAX}, which is no smaller than 65,535.  The minimum
+required by the standard is 127.
+
+@item Number of characters on a logical source line.
+
+The C standard requires a minimum of 4096 be permitted.  GNU CPP places
+no limits on this, but you may get incorrect column numbers reported in
+diagnostics for lines longer than 65,535 characters.
+
+@item Maximum size of a source file.
+
+The standard does not specify any lower limit on the maximum size of a
+source file.  GNU cpp maps files into memory, so it is limited by the
+available address space.  This is generally at least two gigabytes.
+Depending on the operating system, the size of physical memory may or
+may not be a limitation.
+
+@end itemize
+
+@node Obsolete Features
+@section Obsolete Features
+
+GNU CPP has a number of features which are present mainly for
+compatibility with older programs.  We discourage their use in new code.
+In some cases, we plan to remove the feature in a future version of GCC@.
+
+@menu
+* Assertions::
+* Obsolete once-only headers::
+* Miscellaneous obsolete features::
+@end menu
+
+@node Assertions
+@subsection Assertions
+@cindex assertions
+
+@dfn{Assertions} are a deprecated alternative to macros in writing
+conditionals to test what sort of computer or system the compiled
+program will run on.  Assertions are usually predefined, but you can
+define them with preprocessing directives or command-line options.
+
+Assertions were intended to provide a more systematic way to describe
+the compiler's target system.  However, in practice they are just as
+unpredictable as the system-specific predefined macros.  In addition, they
+are not part of any standard, and only a few compilers support them.
+Therefore, the use of assertions is @strong{less} portable than the use
+of system-specific predefined macros.  We recommend you do not use them at
+all.
+
+@cindex predicates
+An assertion looks like this:
+
+@example
+#@var{predicate} (@var{answer})
+@end example
+
+@noindent
+@var{predicate} must be a single identifier.  @var{answer} can be any
+sequence of tokens; all characters are significant except for leading
+and trailing whitespace, and differences in internal whitespace
+sequences are ignored.  (This is similar to the rules governing macro
+redefinition.)  Thus, @code{(x + y)} is different from @code{(x+y)} but
+equivalent to @code{@w{( x + y )}}.  Parentheses do not nest inside an
+answer.
+
+@cindex testing predicates
+To test an assertion, you write it in an @samp{#if}.  For example, this
+conditional succeeds if either @code{vax} or @code{ns16000} has been
+asserted as an answer for @code{machine}.
+
+@example
+#if #machine (vax) || #machine (ns16000)
+@end example
+
+@noindent
+You can test whether @emph{any} answer is asserted for a predicate by
+omitting the answer in the conditional:
+
+@example
+#if #machine
+@end example
+
+@findex #assert
+Assertions are made with the @samp{#assert} directive.  Its sole
+argument is the assertion to make, without the leading @samp{#} that
+identifies assertions in conditionals.
+
+@example
+#assert @var{predicate} (@var{answer})
+@end example
+
+@noindent
+You may make several assertions with the same predicate and different
+answers.  Subsequent assertions do not override previous ones for the
+same predicate.  All the answers for any given predicate are
+simultaneously true.
+
+@cindex assertions, cancelling
+@findex #unassert
+Assertions can be cancelled with the @samp{#unassert} directive.  It
+has the same syntax as @samp{#assert}.  In that form it cancels only the
+answer which was specified on the @samp{#unassert} line; other answers
+for that predicate remain true.  You can cancel an entire predicate by
+leaving out the answer:
+
+@example
+#unassert @var{predicate}
+@end example
+
+@noindent
+In either form, if no such assertion has been made, @samp{#unassert} has
+no effect.
+
+You can also make or cancel assertions using command line options.
+@xref{Invocation}.
+
+@node Obsolete once-only headers
+@subsection Obsolete once-only headers
+
+GNU CPP supports two more ways of indicating that a header file should be
+read only once.  Neither one is as portable as a wrapper @samp{#ifndef},
+and we recommend you do not use them in new programs.
+
+@findex #import
+In the Objective-C language, there is a variant of @samp{#include}
+called @samp{#import} which includes a file, but does so at most once.
+If you use @samp{#import} instead of @samp{#include}, then you don't
+need the conditionals inside the header file to prevent multiple
+inclusion of the contents.  GCC permits the use of @samp{#import} in C
+and C++ as well as Objective-C@.  However, it is not in standard C or C++
+and should therefore not be used by portable programs.
+
+@samp{#import} is not a well designed feature.  It requires the users of
+a header file to know that it should only be included once.  It is much
+better for the header file's implementor to write the file so that users
+don't need to know this.  Using a wrapper @samp{#ifndef} accomplishes
+this goal.
+
+In the present implementation, a single use of @samp{#import} will
+prevent the file from ever being read again, by either @samp{#import} or
+@samp{#include}.  You should not rely on this; do not use both
+@samp{#import} and @samp{#include} to refer to the same header file.
+
+Another way to prevent a header file from being included more than once
+is with the @samp{#pragma once} directive.  If @samp{#pragma once} is
+seen when scanning a header file, that file will never be read again, no
+matter what.
+
+@samp{#pragma once} does not have the problems that @samp{#import} does,
+but it is not recognized by all preprocessors, so you cannot rely on it
+in a portable program.
+
+@node Miscellaneous obsolete features
+@subsection Miscellaneous obsolete features
+
+Here are a few more obsolete features.
+
+@itemize @bullet
+@cindex invalid token paste
+@item Attempting to paste two tokens which together do not form a valid
+preprocessing token.
+
+The preprocessor currently warns about this and outputs the two tokens
+adjacently, which is probably the behavior the programmer intends.  It
+may not work in future, though.
+
+Most of the time, when you get this warning, you will find that @samp{##}
+is being used superstitiously, to guard against whitespace appearing
+between two tokens.  It is almost always safe to delete the @samp{##}.
+
+@cindex pragma poison
+@item @code{#pragma poison}
+
+This is the same as @code{#pragma GCC poison}.  The version without the
+@code{GCC} prefix is deprecated.  @xref{Pragmas}.
+
+@cindex multi-line string constants
+@item Multi-line string constants
+
+GCC currently allows a string constant to extend across multiple logical
+lines of the source file.  This extension is deprecated and will be
+removed in a future version of GCC@.  Such string constants are already
+rejected in all directives apart from @samp{#define}.
+
+Instead, make use of ISO C concatenation of adjacent string literals, or
+use @samp{\n} followed by a backslash-newline.
+
+@end itemize
+
+@node Differences from previous versions
+@section Differences from previous versions
+@cindex differences from previous versions
+
+This section details behavior which has changed from previous versions
+of GNU CPP@.  We do not plan to change it again in the near future, but
+we do not promise not to, either.
+
+The ``previous versions'' discussed here are 2.95 and before.  The
+behavior of GCC 3.0 is mostly the same as the behavior of the widely
+used 2.96 and 2.97 development snapshots.  Where there are differences,
+they generally represent bugs in the snapshots.
+
+@itemize @bullet
+
+@item Order of evaluation of @samp{#} and @samp{##} operators
+
+The standard does not specify the order of evaluation of a chain of
+@samp{##} operators, nor whether @samp{#} is evaluated before, after, or
+at the same time as @samp{##}.  You should therefore not write any code
+which depends on any specific ordering.  It is possible to guarantee an
+ordering, if you need one, by suitable use of nested macros.
+
+An example of where this might matter is pasting the arguments @samp{1},
+@samp{e} and @samp{-2}.  This would be fine for left-to-right pasting,
+but right-to-left pasting would produce an invalid token @samp{e-2}.
+
+GCC 3.0 evaluates @samp{#} and @samp{##} at the same time and strictly
+left to right.  Older versions evaluated all @samp{#} operators first,
+then all @samp{##} operators, in an unreliable order.
+
+@item The form of whitespace betwen tokens in preprocessor output
+
+@xref{Preprocessor Output}, for the current textual format.  This is
+also the format used by stringification.  Normally, the preprocessor
+communicates tokens directly to the compiler's parser, and whitespace
+does not come up at all.
+
+Older versions of GCC preserved all whitespace provided by the user and
+inserted lots more whitespace of their own, because they could not
+accurately predict when extra spaces were needed to prevent accidental
+token pasting.
+
+@item Optional argument when invoking rest argument macros
+
+As an extension, GCC permits you to omit the variable arguments entirely
+when you use a variable argument macro.  This is forbidden by the 1999 C
+standard, and will provoke a pedantic warning with GCC 3.0.  Previous
+versions accepted it silently.
+
+@item @samp{##} swallowing preceding text in rest argument macros
+
+Formerly, in a macro expansion, if @samp{##} appeared before a variable
+arguments parameter, and the set of tokens specified for that argument
+in the macro invocation was empty, previous versions of GNU CPP would
+back up and remove the preceding sequence of non-whitespace characters
+(@strong{not} the preceding token).  This extension is in direct
+conflict with the 1999 C standard and has been drastically pared back.
+
+In the current version of the preprocessor, if @samp{##} appears between
+a comma and a variable arguments parameter, and the variable argument is
+omitted entirely, the comma will be removed from the expansion.  If the
+variable argument is empty, or the token before @samp{##} is not a
+comma, then @samp{##} behaves as a normal token paste.
+
+@item Traditional mode and GNU extensions
+
+Traditional mode used to be implemented in the same program as normal
+preprocessing.  Therefore, all the GNU extensions to the preprocessor
+were still available in traditional mode.  It is now a separate program
+and does not implement any of the GNU extensions, except for a partial
+implementation of assertions.  Even those may be removed in a future
+release.
+@end itemize
+
+@node Invocation
+@chapter Invocation
+@cindex invocation
+@cindex command line
+
+Most often when you use the C preprocessor you will not have to invoke it
+explicitly: the C compiler will do so automatically.  However, the
+preprocessor is sometimes useful on its own.  All the options listed
+here are also acceptable to the C compiler and have the same meaning,
+except that the C compiler has different rules for specifying the output
+file.
+
+@strong{Note:} Whether you use the preprocessor by way of @command{gcc}
+or @command{cpp}, the @dfn{compiler driver} is run first.  This
+program's purpose is to translate your command into invocations of the
+programs that do the actual work.  Their command line interfaces are
+similar but not identical to the documented interface, and may change
+without notice.
+
+@ignore
+@c man begin SYNOPSIS
+cpp [@option{-D}@var{macro}[=@var{defn}]@dots{}] [@option{-U}@var{macro}]
+    [@option{-I}@var{dir}@dots{}] [@option{-W}@var{warn}@dots{}]
+    [@option{-M}|@option{-MM}] [@option{-MG}] [@option{-MF} @var{filename}]
+    [@option{-MP}] [@option{-MQ} @var{target}@dots{}] [@option{-MT} @var{target}@dots{}]
+    [@option{-x} @var{language}] [@option{-std=}@var{standard}]
+    @var{infile} @var{outfile}
+
+Only the most useful options are listed here; see below for the remainder.
+@c man end
+@c man begin SEEALSO
+gpl(7), gfdl(7), fsf-funding(7),
+gcc(1), as(1), ld(1), and the Info entries for @file{cpp}, @file{gcc}, and
+@file{binutils}.
+@c man end
+@end ignore
+
+@c man begin OPTIONS
+The C preprocessor expects two file names as arguments, @var{infile} and
+@var{outfile}.  The preprocessor reads @var{infile} together with any
+other files it specifies with @samp{#include}.  All the output generated
+by the combined input files is written in @var{outfile}.
+
+Either @var{infile} or @var{outfile} may be @option{-}, which as
+@var{infile} means to read from standard input and as @var{outfile}
+means to write to standard output.  Also, if either file is omitted, it
+means the same as if @option{-} had been specified for that file.
+
+Unless otherwise noted, or the option ends in @samp{=}, all options
+which take an argument may have that argument appear either immediately
+after the option, or with a space between option and argument:
+@option{-Ifoo} and @option{-I foo} have the same effect.
+
+@cindex grouping options
+@cindex options, grouping
+Many options have multi-letter names; therefore multiple single-letter
+options may @emph{not} be grouped: @option{-dM} is very different from
+@w{@samp{-d -M}}.
+
+@cindex options
+@table @gcctabopt
+@item -D @var{name}
+Predefine @var{name} as a macro, with definition @code{1}.
+
+@item -D @var{name}=@var{definition}
+Predefine @var{name} as a macro, with definition @var{definition}.
+There are no restrictions on the contents of @var{definition}, but if
+you are invoking the preprocessor from a shell or shell-like program you
+may need to use the shell's quoting syntax to protect characters such as
+spaces that have a meaning in the shell syntax.  If you use more than
+one @option{-D} for the same @var{name}, the rightmost definition takes
+effect.
+
+If you wish to define a function-like macro on the command line, write
+its argument list with surrounding parentheses before the equals sign
+(if any).  Parentheses are meaningful to most shells, so you will need
+to quote the option.  With @command{sh} and @command{csh},
+@option{-D'@var{name}(@var{args@dots{}})=@var{definition}'} works.
+
+@item -U @var{name}
+Cancel any previous definition of @var{name}, either built in or
+provided with a @option{-D} option.
+
+All @option{-imacros @var{file}} and @option{-include @var{file}} options
+are processed after all @option{-D} and @option{-U} options.
+
+@item -undef
+Do not predefine any system-specific macros.  The common predefined
+macros remain defined.
+
+@item -I @var{dir}
+Add the directory @var{dir} to the list of directories to be searched
+for header files.  @xref{Search Path}.  Directories named by @option{-I}
+are searched before the standard system include directories.
+
+It is dangerous to specify a standard system include directory in an
+@option{-I} option.  This defeats the special treatment of system
+headers (@pxref{System Headers}).  It can also defeat the repairs to
+buggy system headers which GCC makes when it is installed.
+
+@item -o @var{file}
+Write output to @var{file}.  This is the same as specifying @var{file}
+as the second non-option argument to @command{cpp}.  @command{gcc} has a
+different interpretation of a second non-option argument, so you must
+use @option{-o} to specify the output file.
+
+@item -Wall
+Turns on all optional warnings which are desirable for normal code.  At
+present this is @option{-Wcomment} and @option{-Wtrigraphs}.  Note that
+many of the preprocessor's warnings are on by default and have no
+options to control them.
+
+@item -Wcomment
+@itemx -Wcomments
+Warn whenever a comment-start sequence @samp{/*} appears in a @samp{/*}
+comment, or whenever a backslash-newline appears in a @samp{//} comment.
+(Both forms have the same effect.)
+
+@item -Wtrigraphs
+Warn if any trigraphs are encountered.  This option used to take effect
+only if @option{-trigraphs} was also specified, but now works
+independently.  Warnings are not given for trigraphs within comments, as
+they do not affect the meaning of the program.
+
+@item -Wtraditional
+Warn about certain constructs that behave differently in traditional and
+ISO C@.  Also warn about ISO C constructs that have no traditional C
+equivalent, and problematic constructs which should be avoided.
+@xref{Traditional Mode}.
+
+@item -Wimport
+Warn the first time @samp{#import} is used.
+
+@item -Wundef
+Warn whenever an identifier which is not a macro is encountered in an
+@samp{#if} directive, outside of @samp{defined}.  Such identifiers are
+replaced with zero.
+
+@item -Werror
+Make all warnings into hard errors.  Source code which triggers warnings
+will be rejected.
+
+@item -Wsystem-headers
+Issue warnings for code in system headers.  These are normally unhelpful
+in finding bugs in your own code, therefore suppressed.  If you are
+responsible for the system library, you may want to see them.
+
+@item -w
+Suppress all warnings, including those which GNU CPP issues by default.
+
+@item -pedantic
+Issue all the mandatory diagnostics listed in the C standard.  Some of
+them are left out by default, since they trigger frequently on harmless
+code.
+
+@item -pedantic-errors
+Issue all the mandatory diagnostics, and make all mandatory diagnostics
+into errors.  This includes mandatory diagnostics that GCC issues
+without @samp{-pedantic} but treats as warnings.
+
+@item -M
+Instead of outputting the result of preprocessing, output a rule
+suitable for @command{make} describing the dependencies of the main
+source file.  The preprocessor outputs one @command{make} rule containing
+the object file name for that source file, a colon, and the names of all
+the included files, including those coming from @option{-include} or
+@option{-imacros} command line options.
+
+Unless specified explicitly (with @option{-MT} or @option{-MQ}), the
+object file name consists of the basename of the source file with any
+suffix replaced with object file suffix.  If there are many included
+files then the rule is split into several lines using @samp{\}-newline.
+The rule has no commands.
+
+@item -MM
+Like @option{-M}, but mention only the files included with @code{@w{#include
+"@var{file}"}} or with @option{-include} or @option{-imacros} command line
+options.  System header files included with @code{@w{#include <@var{file}>}}
+are omitted.
+
+@item -MF @var{file}
+When used with @option{-M} or @option{-MM}, specifies a file to write the
+dependencies to.  This allows the preprocessor to write the preprocessed
+file to stdout normally.  If no @option{-MF} switch is given, CPP sends
+the rules to stdout and suppresses normal preprocessed output.
+
+@item -MG
+When used with @option{-M} or @option{-MM}, @option{-MG} says to treat missing
+header files as generated files and assume they live in the same
+directory as the source file.  It suppresses preprocessed output, as a
+missing header file is ordinarily an error.
+
+This feature is used in automatic updating of makefiles.
+
+@item -MP
+This option instructs CPP to add a phony target for each dependency
+other than the main file, causing each to depend on nothing.  These
+dummy rules work around errors @command{make} gives if you remove header
+files without updating the @file{Makefile} to match.
+
+This is typical output:
+
+@example
+test.o: test.c test.h
+
+test.h:
+@end example
+
+@item -MT @var{target}
+
+Change the target of the rule emitted by dependency generation.  By
+default CPP takes the name of the main input file, including any path,
+deletes any file suffix such as @samp{.c}, and appends the platform's
+usual object suffix.  The result is the target.
+
+An @option{-MT} option will set the target to be exactly the string you
+specify.  If you want multiple targets, you can specify them as a single
+argument to @option{-MT}, or use multiple @option{-MT} options.
+
+For example, @option{@w{-MT '$(objpfx)foo.o'}} might give
+
+@example
+$(objpfx)foo.o: foo.c
+@end example
+
+@item -MQ @var{target}
+
+Same as @option{-MT}, but it quotes any characters which are special to
+Make.  @option{@w{-MQ '$(objpfx)foo.o'}} gives
+
+@example
+$$(objpfx)foo.o: foo.c
+@end example
+
+The default target is automatically quoted, as if it were given with
+@option{-MQ}.
+
+@item -MD @var{file}
+@itemx -MMD @var{file}
+@option{-MD @var{file}} is equivalent to @option{-M -MF @var{file}}, and
+@option{-MMD @var{file}} is equivalent to @option{-MM -MF @var{file}}.
+
+Due to limitations in the compiler driver, you must use these switches
+when you want to generate a dependency file as a side-effect of normal
+compilation.
+
+@item -x c
+@itemx -x c++
+@itemx -x objective-c
+@itemx -x assembler-with-cpp
+Specify the source language: C, C++, Objective-C, or assembly.  This has
+nothing to do with standards conformance or extensions; it merely
+selects which base syntax to expect.  If you give none of these options,
+cpp will deduce the language from the extension of the source file:
+@samp{.c}, @samp{.cc}, @samp{.m}, or @samp{.S}.  Some other common
+extensions for C++ and assembly are also recognized.  If cpp does not
+recognize the extension, it will treat the file as C; this is the most
+generic mode.
+
+@strong{Note:} Previous versions of cpp accepted a @option{-lang} option
+which selected both the language and the standards conformance level.
+This option has been removed, because it conflicts with the @option{-l}
+option.
+
+@item -std=@var{standard}
+@itemx -ansi
+Specify the standard to which the code should conform.  Currently cpp
+only knows about the standards for C; other language standards will be
+added in the future.
+
+@var{standard}
+may be one of:
+@table @code
+@item iso9899:1990
+@itemx c89
+The ISO C standard from 1990.  @samp{c89} is the customary shorthand for
+this version of the standard.
+
+The @option{-ansi} option is equivalent to @option{-std=c89}.
+
+@item iso9899:199409
+The 1990 C standard, as amended in 1994.
+
+@item iso9899:1999
+@itemx c99
+@itemx iso9899:199x
+@itemx c9x
+The revised ISO C standard, published in December 1999.  Before
+publication, this was known as C9X@.
+
+@item gnu89
+The 1990 C standard plus GNU extensions.  This is the default.
+
+@item gnu99
+@itemx gnu9x
+The 1999 C standard plus GNU extensions.
+@end table
+
+@item -I-
+Split the include path.  Any directories specified with @option{-I}
+options before @option{-I-} are searched only for headers requested with
+@code{@w{#include "@var{file}"}}; they are not searched for
+@code{@w{#include <@var{file}>}}.  If additional directories are
+specified with @option{-I} options after the @option{-I-}, those
+directories are searched for all @samp{#include} directives.
+
+In addition, @option{-I-} inhibits the use of the directory of the current
+file directory as the first search directory for @code{@w{#include
+"@var{file}"}}.  @xref{Search Path}.
+
+@item -nostdinc
+Do not search the standard system directories for header files.
+Only the directories you have specified with @option{-I} options
+(and the directory of the current file, if appropriate) are searched.
+
+@item -nostdinc++
+Do not search for header files in the C++-specific standard directories,
+but do still search the other standard directories.  (This option is
+used when building the C++ library.)
+
+@item -include @var{file}
+
+Process @var{file} as if @code{#include "file"} appeared as the first
+line of the primary source file.  However, the first directory searched
+for @var{file} is the preprocessor's working directory @emph{instead of}
+the directory containing the main source file.  If not found there, it
+is searched for in the remainder of the @code{#include "@dots{}"} search
+chain as normal.
+
+If multiple @option{-include} options are given, the files are included
+in the order they appear on the command line.
+
+@item -imacros @var{file}
+
+Exactly like @option{-include}, except that any output produced by
+scanning @var{file} is thrown away.  Macros it defines remain defined.
+This allows you to acquire all the macros from a header without also
+processing its declarations.
+
+All files specified by @option{-imacros} are processed before all files
+specified by @option{-include}.
+
+@item -idirafter @var{dir}
+Search @var{dir} for header files, but do it @emph{after} all
+directories specified with @option{-I} and the standard system directories
+have been exhausted.  @var{dir} is treated as a system include directory.
+
+@item -iprefix @var{prefix}
+Specify @var{prefix} as the prefix for subsequent @option{-iwithprefix}
+options.  If the prefix represents a directory, you should include the
+final @samp{/}.
+
+@item -iwithprefix @var{dir}
+@itemx -iwithprefixbefore @var{dir}
+
+Append @var{dir} to the prefix specified previously with
+@option{-iprefix}, and add the resulting directory to the include search
+path.  @option{-iwithprefixbefore} puts it in the same place @option{-I}
+would; @option{-iwithprefix} puts it where @option{-idirafter} would.
+
+Use of these options is discouraged.
+
+@item -isystem @var{dir}
+Search @var{dir} for header files, after all directories specified by
+@option{-I} but before the standard system directories.  Mark it
+as a system directory, so that it gets the same special treatment as
+is applied to the standard system directories.  @xref{System Headers}.
+
+@item -fpreprocessed
+Indicate to the preprocessor that the input file has already been
+preprocessed.  This suppresses things like macro expansion, trigraph
+conversion, escaped newline splicing, and processing of most directives.
+The preprocessor still recognizes and removes comments, so that you can
+pass a file preprocessed with @option{-C} to the compiler without
+problems.  In this mode the integrated preprocessor is little more than
+a tokenizer for the front ends.
+
+@option{-fpreprocessed} is implicit if the input file has one of the
+extensions @samp{.i}, @samp{.ii} or @samp{.mi}.  These are the
+extensions that GCC uses for preprocessed files created by
+@option{-save-temps}.
+
+@item -ftabstop=@var{width}
+Set the distance between tab stops.  This helps the preprocessor report
+correct column numbers in warnings or errors, even if tabs appear on the
+line.  If the value is less than 1 or greater than 100, the option is
+ignored.  The default is 8.
+
+@item -fno-show-column
+Do not print column numbers in diagnostics.  This may be necessary if
+diagnostics are being scanned by a program that does not understand the
+column numbers, such as @command{dejagnu}.
+
+@item -A @var{predicate}=@var{answer}
+Make an assertion with the predicate @var{predicate} and answer
+@var{answer}.  This form is preferred to the older form @option{-A
+@var{predicate}(@var{answer})}, which is still supported, because
+it does not use shell special characters.  @xref{Assertions}.
+
+@item -A -@var{predicate}=@var{answer}
+Cancel an assertion with the predicate @var{predicate} and answer
+@var{answer}.
+
+@item -A-
+Cancel all predefined assertions and all assertions preceding it on
+the command line.  Also, undefine all predefined macros and all
+macros preceding it on the command line.  (This is a historical wart and
+may change in the future.)
+
+@item -dCHARS
+@var{CHARS} is a sequence of one or more of the following characters,
+and must not be preceded by a space.  Other characters are interpreted
+by the compiler proper, or reserved for future versions of GCC, and so
+are silently ignored.  If you specify characters whose behavior
+conflicts, the result is undefined.
+
+@table @samp
+@item M
+Instead of the normal output, generate a list of @samp{#define}
+directives for all the macros defined during the execution of the
+preprocessor, including predefined macros.  This gives you a way of
+finding out what is predefined in your version of the preprocessor.
+Assuming you have no file @file{foo.h}, the command
+
+@example
+touch foo.h; cpp -dM foo.h
+@end example
+
+@noindent
+will show all the predefined macros.
+
+@item D
+Like @samp{M} except in two respects: it does @emph{not} include the
+predefined macros, and it outputs @emph{both} the @samp{#define}
+directives and the result of preprocessing.  Both kinds of output go to
+the standard output file.
+
+@item N
+Like @samp{D}, but emit only the macro names, not their expansions.
+
+@item I
+Output @samp{#include} directives in addition to the result of
+preprocessing.
+@end table
+
+@item -P
+Inhibit generation of linemarkers in the output from the preprocessor.
+This might be useful when running the preprocessor on something that is
+not C code, and will be sent to a program which might be confused by the
+linemarkers.  @xref{Preprocessor Output}.
+
+@item -C
+Do not discard comments.  All comments are passed through to the output
+file, except for comments in processed directives, which are deleted
+along with the directive.
+
+You should be prepared for side effects when using @option{-C}; it
+causes the preprocessor to treat comments as tokens in their own right.
+For example, comments appearing at the start of what would be a
+directive line have the effect of turning that line into an ordinary
+source line, since the first token on the line is no longer a @samp{#}.
+
+@item -gcc
+Define the macros @sc{__gnuc__}, @sc{__gnuc_minor__} and
+@sc{__gnuc_patchlevel__}.  These are defined automatically when you use
+@command{gcc -E}; you can turn them off in that case with
+@option{-no-gcc}.
+
+@item -traditional
+Try to imitate the behavior of old-fashioned C, as opposed to ISO
+C@.  @xref{Traditional Mode}.
+
+@item -trigraphs
+Process trigraph sequences.  @xref{Initial processing}.
+
+@item -remap
+Enable special code to work around file systems which only permit very
+short file names, such as MS-DOS@.
+
+@item -$
+Forbid the use of @samp{$} in identifiers.  The C standard allows
+implementations to define extra characters that can appear in
+identifiers.  By default GNU CPP permits @samp{$}, a common extension.
+
+@item -h
+@itemx --help
+@itemx --target-help
+Print text describing all the command line options instead of
+preprocessing anything.
+
+@item -v
+Verbose mode.  Print out GNU CPP's version number at the beginning of
+execution, and report the final form of the include path.
+
+@item -H
+Print the name of each header file used, in addition to other normal
+activities.  Each name is indented to show how deep in the
+@samp{#include} stack it is.
+
+@item -version
+@itemx --version
+Print out GNU CPP's version number.  With one dash, proceed to
+preprocess as normal.  With two dashes, exit immediately.
+@end table
+@c man end
+
+@include fdl.texi
+
+@page
+@node Index of Directives
+@unnumbered Index of Directives
+@printindex fn
+
+@node Concept Index
+@unnumbered Concept Index
+@printindex cp
+
+@bye
diff --git a/contrib/gcc/doc/cppinternals.texi b/contrib/gcc/doc/cppinternals.texi
new file mode 100644
index 0000000..3f3d9af
--- /dev/null
+++ b/contrib/gcc/doc/cppinternals.texi
@@ -0,0 +1,1065 @@
+\input texinfo
+@setfilename cppinternals.info
+@settitle The GNU C Preprocessor Internals
+
+@ifinfo
+@dircategory Programming
+@direntry
+* Cpplib: (cppinternals).      Cpplib internals.
+@end direntry
+@end ifinfo
+
+@c @smallbook
+@c @cropmarks
+@c @finalout
+@setchapternewpage odd
+@ifinfo
+This file documents the internals of the GNU C Preprocessor.
+
+Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
+
+Permission is granted to make and distribute verbatim copies of
+this manual provided the copyright notice and this permission notice
+are preserved on all copies.
+
+@ignore
+Permission is granted to process this file through Tex and print the
+results, provided the printed document carries copying permission
+notice identical to this one except for the removal of this paragraph
+(this paragraph not being relevant to the printed manual).
+
+@end ignore
+Permission is granted to copy and distribute modified versions of this
+manual under the conditions for verbatim copying, provided also that
+the entire resulting derived work is distributed under the terms of a
+permission notice identical to this one.
+
+Permission is granted to copy and distribute translations of this manual
+into another language, under the above conditions for modified versions.
+@end ifinfo
+
+@titlepage
+@c @finalout
+@title Cpplib Internals
+@subtitle Last revised January 2002
+@subtitle for GCC version 3.1
+@author Neil Booth
+@page
+@vskip 0pt plus 1filll
+@c man begin COPYRIGHT
+Copyright @copyright{} 2000, 2001, 2002
+Free Software Foundation, Inc.
+
+Permission is granted to make and distribute verbatim copies of
+this manual provided the copyright notice and this permission notice
+are preserved on all copies.
+
+Permission is granted to copy and distribute modified versions of this
+manual under the conditions for verbatim copying, provided also that
+the entire resulting derived work is distributed under the terms of a
+permission notice identical to this one.
+
+Permission is granted to copy and distribute translations of this manual
+into another language, under the above conditions for modified versions.
+@c man end
+@end titlepage
+@contents
+@page
+
+@node Top
+@top
+@chapter Cpplib---the GNU C Preprocessor
+
+The GNU C preprocessor in GCC 3.x has been completely rewritten.  It is
+now implemented as a library, @dfn{cpplib}, so it can be easily shared between
+a stand-alone preprocessor, and a preprocessor integrated with the C,
+C++ and Objective-C front ends.  It is also available for use by other
+programs, though this is not recommended as its exposed interface has
+not yet reached a point of reasonable stability.
+
+The library has been written to be re-entrant, so that it can be used
+to preprocess many files simultaneously if necessary.  It has also been
+written with the preprocessing token as the fundamental unit; the
+preprocessor in previous versions of GCC would operate on text strings
+as the fundamental unit.
+
+This brief manual documents the internals of cpplib, and explains some
+of the tricky issues.  It is intended that, along with the comments in
+the source code, a reasonably competent C programmer should be able to
+figure out what the code is doing, and why things have been implemented
+the way they have.
+
+@menu
+* Conventions::         Conventions used in the code.
+* Lexer::               The combined C, C++ and Objective-C Lexer.
+* Hash Nodes::          All identifiers are entered into a hash table.
+* Macro Expansion::     Macro expansion algorithm.
+* Token Spacing::       Spacing and paste avoidance issues.
+* Line Numbering::      Tracking location within files.
+* Guard Macros::        Optimizing header files with guard macros.
+* Files::               File handling.
+* Index::               Index.
+@end menu
+
+@node Conventions
+@unnumbered Conventions
+@cindex interface
+@cindex header files
+
+cpplib has two interfaces---one is exposed internally only, and the
+other is for both internal and external use.
+
+The convention is that functions and types that are exposed to multiple
+files internally are prefixed with @samp{_cpp_}, and are to be found in
+the file @file{cpphash.h}.  Functions and types exposed to external
+clients are in @file{cpplib.h}, and prefixed with @samp{cpp_}.  For
+historical reasons this is no longer quite true, but we should strive to
+stick to it.
+
+We are striving to reduce the information exposed in @file{cpplib.h} to the
+bare minimum necessary, and then to keep it there.  This makes clear
+exactly what external clients are entitled to assume, and allows us to
+change internals in the future without worrying whether library clients
+are perhaps relying on some kind of undocumented implementation-specific
+behavior.
+
+@node Lexer
+@unnumbered The Lexer
+@cindex lexer
+@cindex newlines
+@cindex escaped newlines
+
+@section Overview
+The lexer is contained in the file @file{cpplex.c}.  It is a hand-coded
+lexer, and not implemented as a state machine.  It can understand C, C++
+and Objective-C source code, and has been extended to allow reasonably
+successful preprocessing of assembly language.  The lexer does not make
+an initial pass to strip out trigraphs and escaped newlines, but handles
+them as they are encountered in a single pass of the input file.  It
+returns preprocessing tokens individually, not a line at a time.
+
+It is mostly transparent to users of the library, since the library's
+interface for obtaining the next token, @code{cpp_get_token}, takes care
+of lexing new tokens, handling directives, and expanding macros as
+necessary.  However, the lexer does expose some functionality so that
+clients of the library can easily spell a given token, such as
+@code{cpp_spell_token} and @code{cpp_token_len}.  These functions are
+useful when generating diagnostics, and for emitting the preprocessed
+output.
+
+@section Lexing a token
+Lexing of an individual token is handled by @code{_cpp_lex_direct} and
+its subroutines.  In its current form the code is quite complicated,
+with read ahead characters and such-like, since it strives to not step
+back in the character stream in preparation for handling non-ASCII file
+encodings.  The current plan is to convert any such files to UTF-8
+before processing them.  This complexity is therefore unnecessary and
+will be removed, so I'll not discuss it further here.
+
+The job of @code{_cpp_lex_direct} is simply to lex a token.  It is not
+responsible for issues like directive handling, returning lookahead
+tokens directly, multiple-include optimization, or conditional block
+skipping.  It necessarily has a minor r@^ole to play in memory
+management of lexed lines.  I discuss these issues in a separate section
+(@pxref{Lexing a line}).
+
+The lexer places the token it lexes into storage pointed to by the
+variable @code{cur_token}, and then increments it.  This variable is
+important for correct diagnostic positioning.  Unless a specific line
+and column are passed to the diagnostic routines, they will examine the
+@code{line} and @code{col} values of the token just before the location
+that @code{cur_token} points to, and use that location to report the
+diagnostic.
+
+The lexer does not consider whitespace to be a token in its own right.
+If whitespace (other than a new line) precedes a token, it sets the
+@code{PREV_WHITE} bit in the token's flags.  Each token has its
+@code{line} and @code{col} variables set to the line and column of the
+first character of the token.  This line number is the line number in
+the translation unit, and can be converted to a source (file, line) pair
+using the line map code.
+
+The first token on a logical, i.e.@: unescaped, line has the flag
+@code{BOL} set for beginning-of-line.  This flag is intended for
+internal use, both to distinguish a @samp{#} that begins a directive
+from one that doesn't, and to generate a call-back to clients that want
+to be notified about the start of every non-directive line with tokens
+on it.  Clients cannot reliably determine this for themselves: the first
+token might be a macro, and the tokens of a macro expansion do not have
+the @code{BOL} flag set.  The macro expansion may even be empty, and the
+next token on the line certainly won't have the @code{BOL} flag set.
+
+New lines are treated specially; exactly how the lexer handles them is
+context-dependent.  The C standard mandates that directives are
+terminated by the first unescaped newline character, even if it appears
+in the middle of a macro expansion.  Therefore, if the state variable
+@code{in_directive} is set, the lexer returns a @code{CPP_EOF} token,
+which is normally used to indicate end-of-file, to indicate
+end-of-directive.  In a directive a @code{CPP_EOF} token never means
+end-of-file.  Conveniently, if the caller was @code{collect_args}, it
+already handles @code{CPP_EOF} as if it were end-of-file, and reports an
+error about an unterminated macro argument list.
+
+The C standard also specifies that a new line in the middle of the
+arguments to a macro is treated as whitespace.  This white space is
+important in case the macro argument is stringified.  The state variable
+@code{parsing_args} is nonzero when the preprocessor is collecting the
+arguments to a macro call.  It is set to 1 when looking for the opening
+parenthesis to a function-like macro, and 2 when collecting the actual
+arguments up to the closing parenthesis, since these two cases need to
+be distinguished sometimes.  One such time is here: the lexer sets the
+@code{PREV_WHITE} flag of a token if it meets a new line when
+@code{parsing_args} is set to 2.  It doesn't set it if it meets a new
+line when @code{parsing_args} is 1, since then code like
+
+@smallexample
+#define foo() bar
+foo
+baz
+@end smallexample
+
+@noindent would be output with an erroneous space before @samp{baz}:
+
+@smallexample
+foo
+ baz
+@end smallexample
+
+This is a good example of the subtlety of getting token spacing correct
+in the preprocessor; there are plenty of tests in the test suite for
+corner cases like this.
+
+The lexer is written to treat each of @samp{\r}, @samp{\n}, @samp{\r\n}
+and @samp{\n\r} as a single new line indicator.  This allows it to
+transparently preprocess MS-DOS, Macintosh and Unix files without their
+needing to pass through a special filter beforehand.
+
+We also decided to treat a backslash, either @samp{\} or the trigraph
+@samp{??/}, separated from one of the above newline indicators by
+non-comment whitespace only, as intending to escape the newline.  It
+tends to be a typing mistake, and cannot reasonably be mistaken for
+anything else in any of the C-family grammars.  Since handling it this
+way is not strictly conforming to the ISO standard, the library issues a
+warning wherever it encounters it.
+
+Handling newlines like this is made simpler by doing it in one place
+only.  The function @code{handle_newline} takes care of all newline
+characters, and @code{skip_escaped_newlines} takes care of arbitrarily
+long sequences of escaped newlines, deferring to @code{handle_newline}
+to handle the newlines themselves.
+
+The most painful aspect of lexing ISO-standard C and C++ is handling
+trigraphs and backlash-escaped newlines.  Trigraphs are processed before
+any interpretation of the meaning of a character is made, and unfortunately
+there is a trigraph representation for a backslash, so it is possible for
+the trigraph @samp{??/} to introduce an escaped newline.
+
+Escaped newlines are tedious because theoretically they can occur
+anywhere---between the @samp{+} and @samp{=} of the @samp{+=} token,
+within the characters of an identifier, and even between the @samp{*}
+and @samp{/} that terminates a comment.  Moreover, you cannot be sure
+there is just one---there might be an arbitrarily long sequence of them.
+
+So, for example, the routine that lexes a number, @code{parse_number},
+cannot assume that it can scan forwards until the first non-number
+character and be done with it, because this could be the @samp{\}
+introducing an escaped newline, or the @samp{?} introducing the trigraph
+sequence that represents the @samp{\} of an escaped newline.  If it
+encounters a @samp{?} or @samp{\}, it calls @code{skip_escaped_newlines}
+to skip over any potential escaped newlines before checking whether the
+number has been finished.
+
+Similarly code in the main body of @code{_cpp_lex_direct} cannot simply
+check for a @samp{=} after a @samp{+} character to determine whether it
+has a @samp{+=} token; it needs to be prepared for an escaped newline of
+some sort.  Such cases use the function @code{get_effective_char}, which
+returns the first character after any intervening escaped newlines.
+
+The lexer needs to keep track of the correct column position, including
+counting tabs as specified by the @option{-ftabstop=} option.  This
+should be done even within C-style comments; they can appear in the
+middle of a line, and we want to report diagnostics in the correct
+position for text appearing after the end of the comment.
+
+@anchor{Invalid identifiers}
+Some identifiers, such as @code{__VA_ARGS__} and poisoned identifiers,
+may be invalid and require a diagnostic.  However, if they appear in a
+macro expansion we don't want to complain with each use of the macro.
+It is therefore best to catch them during the lexing stage, in
+@code{parse_identifier}.  In both cases, whether a diagnostic is needed
+or not is dependent upon the lexer's state.  For example, we don't want
+to issue a diagnostic for re-poisoning a poisoned identifier, or for
+using @code{__VA_ARGS__} in the expansion of a variable-argument macro.
+Therefore @code{parse_identifier} makes use of state flags to determine
+whether a diagnostic is appropriate.  Since we change state on a
+per-token basis, and don't lex whole lines at a time, this is not a
+problem.
+
+Another place where state flags are used to change behavior is whilst
+lexing header names.  Normally, a @samp{<} would be lexed as a single
+token.  After a @code{#include} directive, though, it should be lexed as
+a single token as far as the nearest @samp{>} character.  Note that we
+don't allow the terminators of header names to be escaped; the first
+@samp{"} or @samp{>} terminates the header name.
+
+Interpretation of some character sequences depends upon whether we are
+lexing C, C++ or Objective-C, and on the revision of the standard in
+force.  For example, @samp{::} is a single token in C++, but in C it is
+two separate @samp{:} tokens and almost certainly a syntax error.  Such
+cases are handled by @code{_cpp_lex_direct} based upon command-line
+flags stored in the @code{cpp_options} structure.
+
+Once a token has been lexed, it leads an independent existence.  The
+spelling of numbers, identifiers and strings is copied to permanent
+storage from the original input buffer, so a token remains valid and
+correct even if its source buffer is freed with @code{_cpp_pop_buffer}.
+The storage holding the spellings of such tokens remains until the
+client program calls cpp_destroy, probably at the end of the translation
+unit.
+
+@anchor{Lexing a line}
+@section Lexing a line
+@cindex token run
+
+When the preprocessor was changed to return pointers to tokens, one
+feature I wanted was some sort of guarantee regarding how long a
+returned pointer remains valid.  This is important to the stand-alone
+preprocessor, the future direction of the C family front ends, and even
+to cpplib itself internally.
+
+Occasionally the preprocessor wants to be able to peek ahead in the
+token stream.  For example, after the name of a function-like macro, it
+wants to check the next token to see if it is an opening parenthesis.
+Another example is that, after reading the first few tokens of a
+@code{#pragma} directive and not recognizing it as a registered pragma,
+it wants to backtrack and allow the user-defined handler for unknown
+pragmas to access the full @code{#pragma} token stream.  The stand-alone
+preprocessor wants to be able to test the current token with the
+previous one to see if a space needs to be inserted to preserve their
+separate tokenization upon re-lexing (paste avoidance), so it needs to
+be sure the pointer to the previous token is still valid.  The
+recursive-descent C++ parser wants to be able to perform tentative
+parsing arbitrarily far ahead in the token stream, and then to be able
+to jump back to a prior position in that stream if necessary.
+
+The rule I chose, which is fairly natural, is to arrange that the
+preprocessor lex all tokens on a line consecutively into a token buffer,
+which I call a @dfn{token run}, and when meeting an unescaped new line
+(newlines within comments do not count either), to start lexing back at
+the beginning of the run.  Note that we do @emph{not} lex a line of
+tokens at once; if we did that @code{parse_identifier} would not have
+state flags available to warn about invalid identifiers (@pxref{Invalid
+identifiers}).
+
+In other words, accessing tokens that appeared earlier in the current
+line is valid, but since each logical line overwrites the tokens of the
+previous line, tokens from prior lines are unavailable.  In particular,
+since a directive only occupies a single logical line, this means that
+the directive handlers like the @code{#pragma} handler can jump around
+in the directive's tokens if necessary.
+
+Two issues remain: what about tokens that arise from macro expansions,
+and what happens when we have a long line that overflows the token run?
+
+Since we promise clients that we preserve the validity of pointers that
+we have already returned for tokens that appeared earlier in the line,
+we cannot reallocate the run.  Instead, on overflow it is expanded by
+chaining a new token run on to the end of the existing one.
+
+The tokens forming a macro's replacement list are collected by the
+@code{#define} handler, and placed in storage that is only freed by
+@code{cpp_destroy}.  So if a macro is expanded in our line of tokens,
+the pointers to the tokens of its expansion that we return will always
+remain valid.  However, macros are a little trickier than that, since
+they give rise to three sources of fresh tokens.  They are the built-in
+macros like @code{__LINE__}, and the @samp{#} and @samp{##} operators
+for stringification and token pasting.  I handled this by allocating
+space for these tokens from the lexer's token run chain.  This means
+they automatically receive the same lifetime guarantees as lexed tokens,
+and we don't need to concern ourselves with freeing them.
+
+Lexing into a line of tokens solves some of the token memory management
+issues, but not all.  The opening parenthesis after a function-like
+macro name might lie on a different line, and the front ends definitely
+want the ability to look ahead past the end of the current line.  So
+cpplib only moves back to the start of the token run at the end of a
+line if the variable @code{keep_tokens} is zero.  Line-buffering is
+quite natural for the preprocessor, and as a result the only time cpplib
+needs to increment this variable is whilst looking for the opening
+parenthesis to, and reading the arguments of, a function-like macro.  In
+the near future cpplib will export an interface to increment and
+decrement this variable, so that clients can share full control over the
+lifetime of token pointers too.
+
+The routine @code{_cpp_lex_token} handles moving to new token runs,
+calling @code{_cpp_lex_direct} to lex new tokens, or returning
+previously-lexed tokens if we stepped back in the token stream.  It also
+checks each token for the @code{BOL} flag, which might indicate a
+directive that needs to be handled, or require a start-of-line call-back
+to be made.  @code{_cpp_lex_token} also handles skipping over tokens in
+failed conditional blocks, and invalidates the control macro of the
+multiple-include optimization if a token was successfully lexed outside
+a directive.  In other words, its callers do not need to concern
+themselves with such issues.
+
+@node Hash Nodes
+@unnumbered Hash Nodes
+@cindex hash table
+@cindex identifiers
+@cindex macros
+@cindex assertions
+@cindex named operators
+
+When cpplib encounters an ``identifier'', it generates a hash code for
+it and stores it in the hash table.  By ``identifier'' we mean tokens
+with type @code{CPP_NAME}; this includes identifiers in the usual C
+sense, as well as keywords, directive names, macro names and so on.  For
+example, all of @code{pragma}, @code{int}, @code{foo} and
+@code{__GNUC__} are identifiers and hashed when lexed.
+
+Each node in the hash table contain various information about the
+identifier it represents.  For example, its length and type.  At any one
+time, each identifier falls into exactly one of three categories:
+
+@itemize @bullet
+@item Macros
+
+These have been declared to be macros, either on the command line or
+with @code{#define}.  A few, such as @code{__TIME__} are built-ins
+entered in the hash table during initialization.  The hash node for a
+normal macro points to a structure with more information about the
+macro, such as whether it is function-like, how many arguments it takes,
+and its expansion.  Built-in macros are flagged as special, and instead
+contain an enum indicating which of the various built-in macros it is.
+
+@item Assertions
+
+Assertions are in a separate namespace to macros.  To enforce this, cpp
+actually prepends a @code{#} character before hashing and entering it in
+the hash table.  An assertion's node points to a chain of answers to
+that assertion.
+
+@item Void
+
+Everything else falls into this category---an identifier that is not
+currently a macro, or a macro that has since been undefined with
+@code{#undef}.
+
+When preprocessing C++, this category also includes the named operators,
+such as @code{xor}.  In expressions these behave like the operators they
+represent, but in contexts where the spelling of a token matters they
+are spelt differently.  This spelling distinction is relevant when they
+are operands of the stringizing and pasting macro operators @code{#} and
+@code{##}.  Named operator hash nodes are flagged, both to catch the
+spelling distinction and to prevent them from being defined as macros.
+@end itemize
+
+The same identifiers share the same hash node.  Since each identifier
+token, after lexing, contains a pointer to its hash node, this is used
+to provide rapid lookup of various information.  For example, when
+parsing a @code{#define} statement, CPP flags each argument's identifier
+hash node with the index of that argument.  This makes duplicated
+argument checking an O(1) operation for each argument.  Similarly, for
+each identifier in the macro's expansion, lookup to see if it is an
+argument, and which argument it is, is also an O(1) operation.  Further,
+each directive name, such as @code{endif}, has an associated directive
+enum stored in its hash node, so that directive lookup is also O(1).
+
+@node Macro Expansion
+@unnumbered Macro Expansion Algorithm
+@cindex macro expansion
+
+Macro expansion is a tricky operation, fraught with nasty corner cases
+and situations that render what you thought was a nifty way to
+optimize the preprocessor's expansion algorithm wrong in quite subtle
+ways.
+
+I strongly recommend you have a good grasp of how the C and C++
+standards require macros to be expanded before diving into this
+section, let alone the code!.  If you don't have a clear mental
+picture of how things like nested macro expansion, stringification and
+token pasting are supposed to work, damage to your sanity can quickly
+result.
+
+@section Internal representation of macros
+@cindex macro representation (internal)
+
+The preprocessor stores macro expansions in tokenized form.  This
+saves repeated lexing passes during expansion, at the cost of a small
+increase in memory consumption on average.  The tokens are stored
+contiguously in memory, so a pointer to the first one and a token
+count is all you need to get the replacement list of a macro.
+
+If the macro is a function-like macro the preprocessor also stores its
+parameters, in the form of an ordered list of pointers to the hash
+table entry of each parameter's identifier.  Further, in the macro's
+stored expansion each occurrence of a parameter is replaced with a
+special token of type @code{CPP_MACRO_ARG}.  Each such token holds the
+index of the parameter it represents in the parameter list, which
+allows rapid replacement of parameters with their arguments during
+expansion.  Despite this optimization it is still necessary to store
+the original parameters to the macro, both for dumping with e.g.,
+@option{-dD}, and to warn about non-trivial macro redefinitions when
+the parameter names have changed.
+
+@section Macro expansion overview
+The preprocessor maintains a @dfn{context stack}, implemented as a
+linked list of @code{cpp_context} structures, which together represent
+the macro expansion state at any one time.  The @code{struct
+cpp_reader} member variable @code{context} points to the current top
+of this stack.  The top normally holds the unexpanded replacement list
+of the innermost macro under expansion, except when cpplib is about to
+pre-expand an argument, in which case it holds that argument's
+unexpanded tokens.
+
+When there are no macros under expansion, cpplib is in @dfn{base
+context}.  All contexts other than the base context contain a
+contiguous list of tokens delimited by a starting and ending token.
+When not in base context, cpplib obtains the next token from the list
+of the top context.  If there are no tokens left in the list, it pops
+that context off the stack, and subsequent ones if necessary, until an
+unexhausted context is found or it returns to base context.  In base
+context, cpplib reads tokens directly from the lexer.
+
+If it encounters an identifier that is both a macro and enabled for
+expansion, cpplib prepares to push a new context for that macro on the
+stack by calling the routine @code{enter_macro_context}.  When this
+routine returns, the new context will contain the unexpanded tokens of
+the replacement list of that macro.  In the case of function-like
+macros, @code{enter_macro_context} also replaces any parameters in the
+replacement list, stored as @code{CPP_MACRO_ARG} tokens, with the
+appropriate macro argument.  If the standard requires that the
+parameter be replaced with its expanded argument, the argument will
+have been fully macro expanded first.
+
+@code{enter_macro_context} also handles special macros like
+@code{__LINE__}.  Although these macros expand to a single token which
+cannot contain any further macros, for reasons of token spacing
+(@pxref{Token Spacing}) and simplicity of implementation, cpplib
+handles these special macros by pushing a context containing just that
+one token.
+
+The final thing that @code{enter_macro_context} does before returning
+is to mark the macro disabled for expansion (except for special macros
+like @code{__TIME__}).  The macro is re-enabled when its context is
+later popped from the context stack, as described above.  This strict
+ordering ensures that a macro is disabled whilst its expansion is
+being scanned, but that it is @emph{not} disabled whilst any arguments
+to it are being expanded.
+
+@section Scanning the replacement list for macros to expand
+The C standard states that, after any parameters have been replaced
+with their possibly-expanded arguments, the replacement list is
+scanned for nested macros.  Further, any identifiers in the
+replacement list that are not expanded during this scan are never
+again eligible for expansion in the future, if the reason they were
+not expanded is that the macro in question was disabled.
+
+Clearly this latter condition can only apply to tokens resulting from
+argument pre-expansion.  Other tokens never have an opportunity to be
+re-tested for expansion.  It is possible for identifiers that are
+function-like macros to not expand initially but to expand during a
+later scan.  This occurs when the identifier is the last token of an
+argument (and therefore originally followed by a comma or a closing
+parenthesis in its macro's argument list), and when it replaces its
+parameter in the macro's replacement list, the subsequent token
+happens to be an opening parenthesis (itself possibly the first token
+of an argument).
+
+It is important to note that when cpplib reads the last token of a
+given context, that context still remains on the stack.  Only when
+looking for the @emph{next} token do we pop it off the stack and drop
+to a lower context.  This makes backing up by one token easy, but more
+importantly ensures that the macro corresponding to the current
+context is still disabled when we are considering the last token of
+its replacement list for expansion (or indeed expanding it).  As an
+example, which illustrates many of the points above, consider
+
+@smallexample
+#define foo(x) bar x
+foo(foo) (2)
+@end smallexample
+
+@noindent which fully expands to @samp{bar foo (2)}.  During pre-expansion
+of the argument, @samp{foo} does not expand even though the macro is
+enabled, since it has no following parenthesis [pre-expansion of an
+argument only uses tokens from that argument; it cannot take tokens
+from whatever follows the macro invocation].  This still leaves the
+argument token @samp{foo} eligible for future expansion.  Then, when
+re-scanning after argument replacement, the token @samp{foo} is
+rejected for expansion, and marked ineligible for future expansion,
+since the macro is now disabled.  It is disabled because the
+replacement list @samp{bar foo} of the macro is still on the context
+stack.
+
+If instead the algorithm looked for an opening parenthesis first and
+then tested whether the macro were disabled it would be subtly wrong.
+In the example above, the replacement list of @samp{foo} would be
+popped in the process of finding the parenthesis, re-enabling
+@samp{foo} and expanding it a second time.
+
+@section Looking for a function-like macro's opening parenthesis
+Function-like macros only expand when immediately followed by a
+parenthesis.  To do this cpplib needs to temporarily disable macros
+and read the next token.  Unfortunately, because of spacing issues
+(@pxref{Token Spacing}), there can be fake padding tokens in-between,
+and if the next real token is not a parenthesis cpplib needs to be
+able to back up that one token as well as retain the information in
+any intervening padding tokens.
+
+Backing up more than one token when macros are involved is not
+permitted by cpplib, because in general it might involve issues like
+restoring popped contexts onto the context stack, which are too hard.
+Instead, searching for the parenthesis is handled by a special
+function, @code{funlike_invocation_p}, which remembers padding
+information as it reads tokens.  If the next real token is not an
+opening parenthesis, it backs up that one token, and then pushes an
+extra context just containing the padding information if necessary.
+
+@section Marking tokens ineligible for future expansion
+As discussed above, cpplib needs a way of marking tokens as
+unexpandable.  Since the tokens cpplib handles are read-only once they
+have been lexed, it instead makes a copy of the token and adds the
+flag @code{NO_EXPAND} to the copy.
+
+For efficiency and to simplify memory management by avoiding having to
+remember to free these tokens, they are allocated as temporary tokens
+from the lexer's current token run (@pxref{Lexing a line}) using the
+function @code{_cpp_temp_token}.  The tokens are then re-used once the
+current line of tokens has been read in.
+
+This might sound unsafe.  However, tokens runs are not re-used at the
+end of a line if it happens to be in the middle of a macro argument
+list, and cpplib only wants to back-up more than one lexer token in
+situations where no macro expansion is involved, so the optimization
+is safe.
+
+@node Token Spacing
+@unnumbered Token Spacing
+@cindex paste avoidance
+@cindex spacing
+@cindex token spacing
+
+First, let's look at an issue that only concerns the stand-alone
+preprocessor: we want to guarantee that re-reading its preprocessed
+output results in an identical token stream.  Without taking special
+measures, this might not be the case because of macro substitution.
+For example:
+
+@smallexample
+#define PLUS +
+#define EMPTY
+#define f(x) =x=
++PLUS -EMPTY- PLUS+ f(=)
+        @expansion{} + + - - + + = = =
+@emph{not}
+        @expansion{} ++ -- ++ ===
+@end smallexample
+
+One solution would be to simply insert a space between all adjacent
+tokens.  However, we would like to keep space insertion to a minimum,
+both for aesthetic reasons and because it causes problems for people who
+still try to abuse the preprocessor for things like Fortran source and
+Makefiles.
+
+For now, just notice that when tokens are added (or removed, as shown by
+the @code{EMPTY} example) from the original lexed token stream, we need
+to check for accidental token pasting.  We call this @dfn{paste
+avoidance}.  Token addition and removal can only occur because of macro
+expansion, but accidental pasting can occur in many places: both before
+and after each macro replacement, each argument replacement, and
+additionally each token created by the @samp{#} and @samp{##} operators.
+
+Let's look at how the preprocessor gets whitespace output correct
+normally.  The @code{cpp_token} structure contains a flags byte, and one
+of those flags is @code{PREV_WHITE}.  This is flagged by the lexer, and
+indicates that the token was preceded by whitespace of some form other
+than a new line.  The stand-alone preprocessor can use this flag to
+decide whether to insert a space between tokens in the output.
+
+Now consider the result of the following macro expansion:
+
+@smallexample
+#define add(x, y, z) x + y +z;
+sum = add (1,2, 3);
+        @expansion{} sum = 1 + 2 +3;
+@end smallexample
+
+The interesting thing here is that the tokens @samp{1} and @samp{2} are
+output with a preceding space, and @samp{3} is output without a
+preceding space, but when lexed none of these tokens had that property.
+Careful consideration reveals that @samp{1} gets its preceding
+whitespace from the space preceding @samp{add} in the macro invocation,
+@emph{not} replacement list.  @samp{2} gets its whitespace from the
+space preceding the parameter @samp{y} in the macro replacement list,
+and @samp{3} has no preceding space because parameter @samp{z} has none
+in the replacement list.
+
+Once lexed, tokens are effectively fixed and cannot be altered, since
+pointers to them might be held in many places, in particular by
+in-progress macro expansions.  So instead of modifying the two tokens
+above, the preprocessor inserts a special token, which I call a
+@dfn{padding token}, into the token stream to indicate that spacing of
+the subsequent token is special.  The preprocessor inserts padding
+tokens in front of every macro expansion and expanded macro argument.
+These point to a @dfn{source token} from which the subsequent real token
+should inherit its spacing.  In the above example, the source tokens are
+@samp{add} in the macro invocation, and @samp{y} and @samp{z} in the
+macro replacement list, respectively.
+
+It is quite easy to get multiple padding tokens in a row, for example if
+a macro's first replacement token expands straight into another macro.
+
+@smallexample
+#define foo bar
+#define bar baz
+[foo]
+        @expansion{} [baz]
+@end smallexample
+
+Here, two padding tokens are generated with sources the @samp{foo} token
+between the brackets, and the @samp{bar} token from foo's replacement
+list, respectively.  Clearly the first padding token is the one we
+should use, so our output code should contain a rule that the first
+padding token in a sequence is the one that matters.
+
+But what if we happen to leave a macro expansion?  Adjusting the above
+example slightly:
+
+@smallexample
+#define foo bar
+#define bar EMPTY baz
+#define EMPTY
+[foo] EMPTY;
+        @expansion{} [ baz] ;
+@end smallexample
+
+As shown, now there should be a space before @samp{baz} and the
+semicolon in the output.
+
+The rules we decided above fail for @samp{baz}: we generate three
+padding tokens, one per macro invocation, before the token @samp{baz}.
+We would then have it take its spacing from the first of these, which
+carries source token @samp{foo} with no leading space.
+
+It is vital that cpplib get spacing correct in these examples since any
+of these macro expansions could be stringified, where spacing matters.
+
+So, this demonstrates that not just entering macro and argument
+expansions, but leaving them requires special handling too.  I made
+cpplib insert a padding token with a @code{NULL} source token when
+leaving macro expansions, as well as after each replaced argument in a
+macro's replacement list.  It also inserts appropriate padding tokens on
+either side of tokens created by the @samp{#} and @samp{##} operators.
+I expanded the rule so that, if we see a padding token with a
+@code{NULL} source token, @emph{and} that source token has no leading
+space, then we behave as if we have seen no padding tokens at all.  A
+quick check shows this rule will then get the above example correct as
+well.
+
+Now a relationship with paste avoidance is apparent: we have to be
+careful about paste avoidance in exactly the same locations we have
+padding tokens in order to get white space correct.  This makes
+implementation of paste avoidance easy: wherever the stand-alone
+preprocessor is fixing up spacing because of padding tokens, and it
+turns out that no space is needed, it has to take the extra step to
+check that a space is not needed after all to avoid an accidental paste.
+The function @code{cpp_avoid_paste} advises whether a space is required
+between two consecutive tokens.  To avoid excessive spacing, it tries
+hard to only require a space if one is likely to be necessary, but for
+reasons of efficiency it is slightly conservative and might recommend a
+space where one is not strictly needed.
+
+@node Line Numbering
+@unnumbered Line numbering
+@cindex line numbers
+
+@section Just which line number anyway?
+
+There are three reasonable requirements a cpplib client might have for
+the line number of a token passed to it:
+
+@itemize @bullet
+@item
+The source line it was lexed on.
+@item
+The line it is output on.  This can be different to the line it was
+lexed on if, for example, there are intervening escaped newlines or
+C-style comments.  For example:
+
+@smallexample
+foo /* A long
+comment */ bar \
+baz
+@result{}
+foo bar baz
+@end smallexample
+
+@item
+If the token results from a macro expansion, the line of the macro name,
+or possibly the line of the closing parenthesis in the case of
+function-like macro expansion.
+@end itemize
+
+The @code{cpp_token} structure contains @code{line} and @code{col}
+members.  The lexer fills these in with the line and column of the first
+character of the token.  Consequently, but maybe unexpectedly, a token
+from the replacement list of a macro expansion carries the location of
+the token within the @code{#define} directive, because cpplib expands a
+macro by returning pointers to the tokens in its replacement list.  The
+current implementation of cpplib assigns tokens created from built-in
+macros and the @samp{#} and @samp{##} operators the location of the most
+recently lexed token.  This is a because they are allocated from the
+lexer's token runs, and because of the way the diagnostic routines infer
+the appropriate location to report.
+
+The diagnostic routines in cpplib display the location of the most
+recently @emph{lexed} token, unless they are passed a specific line and
+column to report.  For diagnostics regarding tokens that arise from
+macro expansions, it might also be helpful for the user to see the
+original location in the macro definition that the token came from.
+Since that is exactly the information each token carries, such an
+enhancement could be made relatively easily in future.
+
+The stand-alone preprocessor faces a similar problem when determining
+the correct line to output the token on: the position attached to a
+token is fairly useless if the token came from a macro expansion.  All
+tokens on a logical line should be output on its first physical line, so
+the token's reported location is also wrong if it is part of a physical
+line other than the first.
+
+To solve these issues, cpplib provides a callback that is generated
+whenever it lexes a preprocessing token that starts a new logical line
+other than a directive.  It passes this token (which may be a
+@code{CPP_EOF} token indicating the end of the translation unit) to the
+callback routine, which can then use the line and column of this token
+to produce correct output.
+
+@section Representation of line numbers
+
+As mentioned above, cpplib stores with each token the line number that
+it was lexed on.  In fact, this number is not the number of the line in
+the source file, but instead bears more resemblance to the number of the
+line in the translation unit.
+
+The preprocessor maintains a monotonic increasing line count, which is
+incremented at every new line character (and also at the end of any
+buffer that does not end in a new line).  Since a line number of zero is
+useful to indicate certain special states and conditions, this variable
+starts counting from one.
+
+This variable therefore uniquely enumerates each line in the translation
+unit.  With some simple infrastructure, it is straight forward to map
+from this to the original source file and line number pair, saving space
+whenever line number information needs to be saved.  The code the
+implements this mapping lies in the files @file{line-map.c} and
+@file{line-map.h}.
+
+Command-line macros and assertions are implemented by pushing a buffer
+containing the right hand side of an equivalent @code{#define} or
+@code{#assert} directive.  Some built-in macros are handled similarly.
+Since these are all processed before the first line of the main input
+file, it will typically have an assigned line closer to twenty than to
+one.
+
+@node Guard Macros
+@unnumbered The Multiple-Include Optimization
+@cindex guard macros
+@cindex controlling macros
+@cindex multiple-include optimization
+
+Header files are often of the form
+
+@smallexample
+#ifndef FOO
+#define FOO
+@dots{}
+#endif
+@end smallexample
+
+@noindent
+to prevent the compiler from processing them more than once.  The
+preprocessor notices such header files, so that if the header file
+appears in a subsequent @code{#include} directive and @code{FOO} is
+defined, then it is ignored and it doesn't preprocess or even re-open
+the file a second time.  This is referred to as the @dfn{multiple
+include optimization}.
+
+Under what circumstances is such an optimization valid?  If the file
+were included a second time, it can only be optimized away if that
+inclusion would result in no tokens to return, and no relevant
+directives to process.  Therefore the current implementation imposes
+requirements and makes some allowances as follows:
+
+@enumerate
+@item
+There must be no tokens outside the controlling @code{#if}-@code{#endif}
+pair, but whitespace and comments are permitted.
+
+@item
+There must be no directives outside the controlling directive pair, but
+the @dfn{null directive} (a line containing nothing other than a single
+@samp{#} and possibly whitespace) is permitted.
+
+@item
+The opening directive must be of the form
+
+@smallexample
+#ifndef FOO
+@end smallexample
+
+or
+
+@smallexample
+#if !defined FOO     [equivalently, #if !defined(FOO)]
+@end smallexample
+
+@item
+In the second form above, the tokens forming the @code{#if} expression
+must have come directly from the source file---no macro expansion must
+have been involved.  This is because macro definitions can change, and
+tracking whether or not a relevant change has been made is not worth the
+implementation cost.
+
+@item
+There can be no @code{#else} or @code{#elif} directives at the outer
+conditional block level, because they would probably contain something
+of interest to a subsequent pass.
+@end enumerate
+
+First, when pushing a new file on the buffer stack,
+@code{_stack_include_file} sets the controlling macro @code{mi_cmacro} to
+@code{NULL}, and sets @code{mi_valid} to @code{true}.  This indicates
+that the preprocessor has not yet encountered anything that would
+invalidate the multiple-include optimization.  As described in the next
+few paragraphs, these two variables having these values effectively
+indicates top-of-file.
+
+When about to return a token that is not part of a directive,
+@code{_cpp_lex_token} sets @code{mi_valid} to @code{false}.  This
+enforces the constraint that tokens outside the controlling conditional
+block invalidate the optimization.
+
+The @code{do_if}, when appropriate, and @code{do_ifndef} directive
+handlers pass the controlling macro to the function
+@code{push_conditional}.  cpplib maintains a stack of nested conditional
+blocks, and after processing every opening conditional this function
+pushes an @code{if_stack} structure onto the stack.  In this structure
+it records the controlling macro for the block, provided there is one
+and we're at top-of-file (as described above).  If an @code{#elif} or
+@code{#else} directive is encountered, the controlling macro for that
+block is cleared to @code{NULL}.  Otherwise, it survives until the
+@code{#endif} closing the block, upon which @code{do_endif} sets
+@code{mi_valid} to true and stores the controlling macro in
+@code{mi_cmacro}.
+
+@code{_cpp_handle_directive} clears @code{mi_valid} when processing any
+directive other than an opening conditional and the null directive.
+With this, and requiring top-of-file to record a controlling macro, and
+no @code{#else} or @code{#elif} for it to survive and be copied to
+@code{mi_cmacro} by @code{do_endif}, we have enforced the absence of
+directives outside the main conditional block for the optimization to be
+on.
+
+Note that whilst we are inside the conditional block, @code{mi_valid} is
+likely to be reset to @code{false}, but this does not matter since the
+the closing @code{#endif} restores it to @code{true} if appropriate.
+
+Finally, since @code{_cpp_lex_direct} pops the file off the buffer stack
+at @code{EOF} without returning a token, if the @code{#endif} directive
+was not followed by any tokens, @code{mi_valid} is @code{true} and
+@code{_cpp_pop_file_buffer} remembers the controlling macro associated
+with the file.  Subsequent calls to @code{stack_include_file} result in
+no buffer being pushed if the controlling macro is defined, effecting
+the optimization.
+
+A quick word on how we handle the
+
+@smallexample
+#if !defined FOO
+@end smallexample
+
+@noindent
+case.  @code{_cpp_parse_expr} and @code{parse_defined} take steps to see
+whether the three stages @samp{!}, @samp{defined-expression} and
+@samp{end-of-directive} occur in order in a @code{#if} expression.  If
+so, they return the guard macro to @code{do_if} in the variable
+@code{mi_ind_cmacro}, and otherwise set it to @code{NULL}.
+@code{enter_macro_context} sets @code{mi_valid} to false, so if a macro
+was expanded whilst parsing any part of the expression, then the
+top-of-file test in @code{push_conditional} fails and the optimization
+is turned off.
+
+@node Files
+@unnumbered File Handling
+@cindex files
+
+Fairly obviously, the file handling code of cpplib resides in the file
+@file{cppfiles.c}.  It takes care of the details of file searching,
+opening, reading and caching, for both the main source file and all the
+headers it recursively includes.
+
+The basic strategy is to minimize the number of system calls.  On many
+systems, the basic @code{open ()} and @code{fstat ()} system calls can
+be quite expensive.  For every @code{#include}-d file, we need to try
+all the directories in the search path until we find a match.  Some
+projects, such as glibc, pass twenty or thirty include paths on the
+command line, so this can rapidly become time consuming.
+
+For a header file we have not encountered before we have little choice
+but to do this.  However, it is often the case that the same headers are
+repeatedly included, and in these cases we try to avoid repeating the
+filesystem queries whilst searching for the correct file.
+
+For each file we try to open, we store the constructed path in a splay
+tree.  This path first undergoes simplification by the function
+@code{_cpp_simplify_pathname}.  For example,
+@file{/usr/include/bits/../foo.h} is simplified to
+@file{/usr/include/foo.h} before we enter it in the splay tree and try
+to @code{open ()} the file.  CPP will then find subsequent uses of
+@file{foo.h}, even as @file{/usr/include/foo.h}, in the splay tree and
+save system calls.
+
+Further, it is likely the file contents have also been cached, saving a
+@code{read ()} system call.  We don't bother caching the contents of
+header files that are re-inclusion protected, and whose re-inclusion
+macro is defined when we leave the header file for the first time.  If
+the host supports it, we try to map suitably large files into memory,
+rather than reading them in directly.
+
+The include paths are internally stored on a null-terminated
+singly-linked list, starting with the @code{"header.h"} directory search
+chain, which then links into the @code{<header.h>} directory chain.
+
+Files included with the @code{<foo.h>} syntax start the lookup directly
+in the second half of this chain.  However, files included with the
+@code{"foo.h"} syntax start at the beginning of the chain, but with one
+extra directory prepended.  This is the directory of the current file;
+the one containing the @code{#include} directive.  Prepending this
+directory on a per-file basis is handled by the function
+@code{search_from}.
+
+Note that a header included with a directory component, such as
+@code{#include "mydir/foo.h"} and opened as
+@file{/usr/local/include/mydir/foo.h}, will have the complete path minus
+the basename @samp{foo.h} as the current directory.
+
+Enough information is stored in the splay tree that CPP can immediately
+tell whether it can skip the header file because of the multiple include
+optimization, whether the file didn't exist or couldn't be opened for
+some reason, or whether the header was flagged not to be re-used, as it
+is with the obsolete @code{#import} directive.
+
+For the benefit of MS-DOS filesystems with an 8.3 filename limitation,
+CPP offers the ability to treat various include file names as aliases
+for the real header files with shorter names.  The map from one to the
+other is found in a special file called @samp{header.gcc}, stored in the
+command line (or system) include directories to which the mapping
+applies.  This may be higher up the directory tree than the full path to
+the file minus the base name.
+
+@node Index
+@unnumbered Index
+@printindex cp
+
+@bye
diff --git a/contrib/gcc/doc/extend.texi b/contrib/gcc/doc/extend.texi
new file mode 100644
index 0000000..ad88a2a
--- /dev/null
+++ b/contrib/gcc/doc/extend.texi
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+@c Copyright (C) 1988,1989,1992,1993,1994,1996,1998,1999,2000,2001,2002 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node C Implementation
+@chapter C Implementation-defined behavior
+@cindex implementation-defined behavior, C language
+
+A conforming implementation of ISO C is required to document its
+choice of behavior in each of the areas that are designated
+``implementation defined.''  The following lists all such areas,
+along with the section number from the ISO/IEC 9899:1999 standard.
+
+@menu
+* Translation implementation::
+* Environment implementation::
+* Identifiers implementation::
+* Characters implementation::
+* Integers implementation::
+* Floating point implementation::
+* Arrays and pointers implementation::
+* Hints implementation::
+* Structures unions enumerations and bit-fields implementation::
+* Qualifiers implementation::
+* Preprocessing directives implementation::
+* Library functions implementation::
+* Architecture implementation::
+* Locale-specific behavior implementation::
+@end menu
+
+@node Translation implementation
+@section Translation
+
+@itemize @bullet
+@item
+@cite{How a diagnostic is identified (3.10, 5.1.1.3).}
+
+@item
+@cite{Whether each nonempty sequence of white-space characters other than
+new-line is retained or replaced by one space character in translation
+phase 3 (5.1.1.2).}
+@end itemize
+
+@node Environment implementation
+@section Environment
+
+The behavior of these points are dependent on the implementation
+of the C library, and are not defined by GCC itself.
+
+@node Identifiers implementation
+@section Identifiers
+
+@itemize @bullet
+@item
+@cite{Which additional multibyte characters may appear in identifiers
+and their correspondence to universal character names (6.4.2).}
+
+@item
+@cite{The number of significant initial characters in an identifier
+(5.2.4.1, 6.4.2).}
+@end itemize
+
+@node Characters implementation
+@section Characters
+
+@itemize @bullet
+@item
+@cite{The number of bits in a byte (3.6).}
+
+@item
+@cite{The values of the members of the execution character set (5.2.1).}
+
+@item
+@cite{The unique value of the member of the execution character set produced
+for each of the standard alphabetic escape sequences (5.2.2).}
+
+@item
+@cite{The value of a @code{char} object into which has been stored any
+character other than a member of the basic execution character set (6.2.5).}
+
+@item
+@cite{Which of @code{signed char} or @code{unsigned char} has the same range,
+representation, and behavior as ``plain'' @code{char} (6.2.5, 6.3.1.1).}
+
+@item
+@cite{The mapping of members of the source character set (in character
+constants and string literals) to members of the execution character
+set (6.4.4.4, 5.1.1.2).}
+
+@item
+@cite{The value of an integer character constant containing more than one
+character or containing a character or escape sequence that does not map
+to a single-byte execution character (6.4.4.4).}
+
+@item
+@cite{The value of a wide character constant containing more than one
+multibyte character, or containing a multibyte character or escape
+sequence not represented in the extended execution character set (6.4.4.4).}
+
+@item
+@cite{The current locale used to convert a wide character constant consisting
+of a single multibyte character that maps to a member of the extended
+execution character set into a corresponding wide character code (6.4.4.4).}
+
+@item
+@cite{The current locale used to convert a wide string literal into
+corresponding wide character codes (6.4.5).}
+
+@item
+@cite{The value of a string literal containing a multibyte character or escape
+sequence not represented in the execution character set (6.4.5).}
+@end itemize
+
+@node Integers implementation
+@section Integers
+
+@itemize @bullet
+@item
+@cite{Any extended integer types that exist in the implementation (6.2.5).}
+
+@item
+@cite{Whether signed integer types are represented using sign and magnitude,
+two's complement, or one's complement, and whether the extraordinary value
+is a trap representation or an ordinary value (6.2.6.2).}
+
+@item
+@cite{The rank of any extended integer type relative to another extended
+integer type with the same precision (6.3.1.1).}
+
+@item
+@cite{The result of, or the signal raised by, converting an integer to a
+signed integer type when the value cannot be represented in an object of
+that type (6.3.1.3).}
+
+@item
+@cite{The results of some bitwise operations on signed integers (6.5).}
+@end itemize
+
+@node Floating point implementation
+@section Floating point
+
+@itemize @bullet
+@item
+@cite{The accuracy of the floating-point operations and of the library
+functions in @code{<math.h>} and @code{<complex.h>} that return floating-point
+results (5.2.4.2.2).}
+
+@item
+@cite{The rounding behaviors characterized by non-standard values
+of @code{FLT_ROUNDS} @gol
+(5.2.4.2.2).}
+
+@item
+@cite{The evaluation methods characterized by non-standard negative
+values of @code{FLT_EVAL_METHOD} (5.2.4.2.2).}
+
+@item
+@cite{The direction of rounding when an integer is converted to a
+floating-point number that cannot exactly represent the original
+value (6.3.1.4).}
+
+@item
+@cite{The direction of rounding when a floating-point number is
+converted to a narrower floating-point number (6.3.1.5).}
+
+@item
+@cite{How the nearest representable value or the larger or smaller
+representable value immediately adjacent to the nearest representable
+value is chosen for certain floating constants (6.4.4.2).}
+
+@item
+@cite{Whether and how floating expressions are contracted when not
+disallowed by the @code{FP_CONTRACT} pragma (6.5).}
+
+@item
+@cite{The default state for the @code{FENV_ACCESS} pragma (7.6.1).}
+
+@item
+@cite{Additional floating-point exceptions, rounding modes, environments,
+and classifications, and their macro names (7.6, 7.12).}
+
+@item
+@cite{The default state for the @code{FP_CONTRACT} pragma (7.12.2).}
+
+@item
+@cite{Whether the ``inexact'' floating-point exception can be raised
+when the rounded result actually does equal the mathematical result
+in an IEC 60559 conformant implementation (F.9).}
+
+@item
+@cite{Whether the ``underflow'' (and ``inexact'') floating-point
+exception can be raised when a result is tiny but not inexact in an
+IEC 60559 conformant implementation (F.9).}
+
+@end itemize
+
+@node Arrays and pointers implementation
+@section Arrays and pointers
+
+@itemize @bullet
+@item
+@cite{The result of converting a pointer to an integer or
+vice versa (6.3.2.3).}
+
+A cast from pointer to integer discards most-significant bits if the
+pointer representation is larger than the integer type,
+sign-extends@footnote{Future versions of GCC may zero-extend, or use
+a target-defined @code{ptr_extend} pattern.  Do not rely on sign extension.}
+if the pointer representation is smaller than the integer type, otherwise
+the bits are unchanged.
+@c ??? We've always claimed that pointers were unsigned entities.
+@c Shouldn't we therefore be doing zero-extension?  If so, the bug
+@c is in convert_to_integer, where we call type_for_size and request
+@c a signed integral type.  On the other hand, it might be most useful
+@c for the target if we extend according to POINTERS_EXTEND_UNSIGNED.
+
+A cast from integer to pointer discards most-significant bits if the
+pointer representation is smaller than the integer type, extends according
+to the signedness of the integer type if the pointer representation
+is larger than the integer type, otherwise the bits are unchanged.
+
+When casting from pointer to integer and back again, the resulting
+pointer must reference the same object as the original pointer, otherwise
+the behavior is undefined.  That is, one may not use integer arithmetic to
+avoid the undefined behavior of pointer arithmetic as proscribed in 6.5.6/8.
+
+@item
+@cite{The size of the result of subtracting two pointers to elements
+of the same array (6.5.6).}
+
+@end itemize
+
+@node Hints implementation
+@section Hints
+
+@itemize @bullet
+@item
+@cite{The extent to which suggestions made by using the @code{register}
+storage-class specifier are effective (6.7.1).}
+
+@item
+@cite{The extent to which suggestions made by using the inline function
+specifier are effective (6.7.4).}
+
+@end itemize
+
+@node Structures unions enumerations and bit-fields implementation
+@section Structures, unions, enumerations, and bit-fields
+
+@itemize @bullet
+@item
+@cite{Whether a ``plain'' int bit-field is treated as a @code{signed int}
+bit-field or as an @code{unsigned int} bit-field (6.7.2, 6.7.2.1).}
+
+@item
+@cite{Allowable bit-field types other than @code{_Bool}, @code{signed int},
+and @code{unsigned int} (6.7.2.1).}
+
+@item
+@cite{Whether a bit-field can straddle a storage-unit boundary (6.7.2.1).}
+
+@item
+@cite{The order of allocation of bit-fields within a unit (6.7.2.1).}
+
+@item
+@cite{The alignment of non-bit-field members of structures (6.7.2.1).}
+
+@item
+@cite{The integer type compatible with each enumerated type (6.7.2.2).}
+
+@end itemize
+
+@node Qualifiers implementation
+@section Qualifiers
+
+@itemize @bullet
+@item
+@cite{What constitutes an access to an object that has volatile-qualified
+type (6.7.3).}
+
+@end itemize
+
+@node Preprocessing directives implementation
+@section Preprocessing directives
+
+@itemize @bullet
+@item
+@cite{How sequences in both forms of header names are mapped to headers
+or external source file names (6.4.7).}
+
+@item
+@cite{Whether the value of a character constant in a constant expression
+that controls conditional inclusion matches the value of the same character
+constant in the execution character set (6.10.1).}
+
+@item
+@cite{Whether the value of a single-character character constant in a
+constant expression that controls conditional inclusion may have a
+negative value (6.10.1).}
+
+@item
+@cite{The places that are searched for an included @samp{<>} delimited
+header, and how the places are specified or the header is
+identified (6.10.2).}
+
+@item
+@cite{How the named source file is searched for in an included @samp{""}
+delimited header (6.10.2).}
+
+@item
+@cite{The method by which preprocessing tokens (possibly resulting from
+macro expansion) in a @code{#include} directive are combined into a header
+name (6.10.2).}
+
+@item
+@cite{The nesting limit for @code{#include} processing (6.10.2).}
+
+@item
+@cite{Whether the @samp{#} operator inserts a @samp{\} character before
+the @samp{\} character that begins a universal character name in a
+character constant or string literal (6.10.3.2).}
+
+@item
+@cite{The behavior on each recognized non-@code{STDC #pragma}
+directive (6.10.6).}
+
+@item
+@cite{The definitions for @code{__DATE__} and @code{__TIME__} when
+respectively, the date and time of translation are not available (6.10.8).}
+
+@end itemize
+
+@node Library functions implementation
+@section Library functions
+
+The behavior of these points are dependent on the implementation
+of the C library, and are not defined by GCC itself.
+
+@node Architecture implementation
+@section Architecture
+
+@itemize @bullet
+@item
+@cite{The values or expressions assigned to the macros specified in the
+headers @code{<float.h>}, @code{<limits.h>}, and @code{<stdint.h>}
+(5.2.4.2, 7.18.2, 7.18.3).}
+
+@item
+@cite{The number, order, and encoding of bytes in any object
+(when not explicitly specified in this International Standard) (6.2.6.1).}
+
+@item
+@cite{The value of the result of the sizeof operator (6.5.3.4).}
+
+@end itemize
+
+@node Locale-specific behavior implementation
+@section Locale-specific behavior
+
+The behavior of these points are dependent on the implementation
+of the C library, and are not defined by GCC itself.
+
+@node C Extensions
+@chapter Extensions to the C Language Family
+@cindex extensions, C language
+@cindex C language extensions
+
+@opindex pedantic
+GNU C provides several language features not found in ISO standard C@.
+(The @option{-pedantic} option directs GCC to print a warning message if
+any of these features is used.)  To test for the availability of these
+features in conditional compilation, check for a predefined macro
+@code{__GNUC__}, which is always defined under GCC@.
+
+These extensions are available in C and Objective-C@.  Most of them are
+also available in C++.  @xref{C++ Extensions,,Extensions to the
+C++ Language}, for extensions that apply @emph{only} to C++.
+
+Some features that are in ISO C99 but not C89 or C++ are also, as
+extensions, accepted by GCC in C89 mode and in C++.
+
+@menu
+* Statement Exprs::     Putting statements and declarations inside expressions.
+* Local Labels::        Labels local to a statement-expression.
+* Labels as Values::    Getting pointers to labels, and computed gotos.
+* Nested Functions::    As in Algol and Pascal, lexical scoping of functions.
+* Constructing Calls::	Dispatching a call to another function.
+* Naming Types::        Giving a name to the type of some expression.
+* Typeof::              @code{typeof}: referring to the type of an expression.
+* Lvalues::             Using @samp{?:}, @samp{,} and casts in lvalues.
+* Conditionals::        Omitting the middle operand of a @samp{?:} expression.
+* Long Long::		Double-word integers---@code{long long int}.
+* Complex::             Data types for complex numbers.
+* Hex Floats::          Hexadecimal floating-point constants.
+* Zero Length::         Zero-length arrays.
+* Variable Length::     Arrays whose length is computed at run time.
+* Variadic Macros::	Macros with a variable number of arguments.
+* Escaped Newlines::    Slightly looser rules for escaped newlines.
+* Multi-line Strings::  String literals with embedded newlines.
+* Subscripting::        Any array can be subscripted, even if not an lvalue.
+* Pointer Arith::       Arithmetic on @code{void}-pointers and function pointers.
+* Initializers::        Non-constant initializers.
+* Compound Literals::   Compound literals give structures, unions
+                         or arrays as values.
+* Designated Inits::	Labeling elements of initializers.
+* Cast to Union::       Casting to union type from any member of the union.
+* Case Ranges::		`case 1 ... 9' and such.
+* Mixed Declarations::	Mixing declarations and code.
+* Function Attributes:: Declaring that functions have no side effects,
+                         or that they can never return.
+* Attribute Syntax::    Formal syntax for attributes.
+* Function Prototypes:: Prototype declarations and old-style definitions.
+* C++ Comments::        C++ comments are recognized.
+* Dollar Signs::        Dollar sign is allowed in identifiers.
+* Character Escapes::   @samp{\e} stands for the character @key{ESC}.
+* Variable Attributes::	Specifying attributes of variables.
+* Type Attributes::	Specifying attributes of types.
+* Alignment::           Inquiring about the alignment of a type or variable.
+* Inline::              Defining inline functions (as fast as macros).
+* Extended Asm::        Assembler instructions with C expressions as operands.
+                         (With them you can define ``built-in'' functions.)
+* Constraints::         Constraints for asm operands
+* Asm Labels::          Specifying the assembler name to use for a C symbol.
+* Explicit Reg Vars::   Defining variables residing in specified registers.
+* Alternate Keywords::  @code{__const__}, @code{__asm__}, etc., for header files.
+* Incomplete Enums::    @code{enum foo;}, with details to follow.
+* Function Names::	Printable strings which are the name of the current
+			 function.
+* Return Address::      Getting the return or frame address of a function.
+* Vector Extensions::   Using vector instructions through built-in functions.
+* Other Builtins::      Other built-in functions.
+* Target Builtins::     Built-in functions specific to particular targets.
+* Pragmas::             Pragmas accepted by GCC.
+* Unnamed Fields::      Unnamed struct/union fields within structs/unions.
+@end menu
+
+@node Statement Exprs
+@section Statements and Declarations in Expressions
+@cindex statements inside expressions
+@cindex declarations inside expressions
+@cindex expressions containing statements
+@cindex macros, statements in expressions
+
+@c the above section title wrapped and causes an underfull hbox.. i
+@c changed it from "within" to "in". --mew 4feb93
+
+A compound statement enclosed in parentheses may appear as an expression
+in GNU C@.  This allows you to use loops, switches, and local variables
+within an expression.
+
+Recall that a compound statement is a sequence of statements surrounded
+by braces; in this construct, parentheses go around the braces.  For
+example:
+
+@example
+(@{ int y = foo (); int z;
+   if (y > 0) z = y;
+   else z = - y;
+   z; @})
+@end example
+
+@noindent
+is a valid (though slightly more complex than necessary) expression
+for the absolute value of @code{foo ()}.
+
+The last thing in the compound statement should be an expression
+followed by a semicolon; the value of this subexpression serves as the
+value of the entire construct.  (If you use some other kind of statement
+last within the braces, the construct has type @code{void}, and thus
+effectively no value.)
+
+This feature is especially useful in making macro definitions ``safe'' (so
+that they evaluate each operand exactly once).  For example, the
+``maximum'' function is commonly defined as a macro in standard C as
+follows:
+
+@example
+#define max(a,b) ((a) > (b) ? (a) : (b))
+@end example
+
+@noindent
+@cindex side effects, macro argument
+But this definition computes either @var{a} or @var{b} twice, with bad
+results if the operand has side effects.  In GNU C, if you know the
+type of the operands (here let's assume @code{int}), you can define
+the macro safely as follows:
+
+@example
+#define maxint(a,b) \
+  (@{int _a = (a), _b = (b); _a > _b ? _a : _b; @})
+@end example
+
+Embedded statements are not allowed in constant expressions, such as
+the value of an enumeration constant, the width of a bit-field, or
+the initial value of a static variable.
+
+If you don't know the type of the operand, you can still do this, but you
+must use @code{typeof} (@pxref{Typeof}) or type naming (@pxref{Naming
+Types}).
+
+Statement expressions are not supported fully in G++, and their fate
+there is unclear.  (It is possible that they will become fully supported
+at some point, or that they will be deprecated, or that the bugs that
+are present will continue to exist indefinitely.)  Presently, statement
+expressions do not work well as default arguments.
+
+In addition, there are semantic issues with statement-expressions in
+C++.  If you try to use statement-expressions instead of inline
+functions in C++, you may be surprised at the way object destruction is
+handled.  For example:
+
+@example
+#define foo(a)  (@{int b = (a); b + 3; @})
+@end example
+
+@noindent
+does not work the same way as:
+
+@example
+inline int foo(int a) @{ int b = a; return b + 3; @}
+@end example
+
+@noindent
+In particular, if the expression passed into @code{foo} involves the
+creation of temporaries, the destructors for those temporaries will be
+run earlier in the case of the macro than in the case of the function.
+
+These considerations mean that it is probably a bad idea to use
+statement-expressions of this form in header files that are designed to
+work with C++.  (Note that some versions of the GNU C Library contained
+header files using statement-expression that lead to precisely this
+bug.)
+
+@node Local Labels
+@section Locally Declared Labels
+@cindex local labels
+@cindex macros, local labels
+
+Each statement expression is a scope in which @dfn{local labels} can be
+declared.  A local label is simply an identifier; you can jump to it
+with an ordinary @code{goto} statement, but only from within the
+statement expression it belongs to.
+
+A local label declaration looks like this:
+
+@example
+__label__ @var{label};
+@end example
+
+@noindent
+or
+
+@example
+__label__ @var{label1}, @var{label2}, @dots{};
+@end example
+
+Local label declarations must come at the beginning of the statement
+expression, right after the @samp{(@{}, before any ordinary
+declarations.
+
+The label declaration defines the label @emph{name}, but does not define
+the label itself.  You must do this in the usual way, with
+@code{@var{label}:}, within the statements of the statement expression.
+
+The local label feature is useful because statement expressions are
+often used in macros.  If the macro contains nested loops, a @code{goto}
+can be useful for breaking out of them.  However, an ordinary label
+whose scope is the whole function cannot be used: if the macro can be
+expanded several times in one function, the label will be multiply
+defined in that function.  A local label avoids this problem.  For
+example:
+
+@example
+#define SEARCH(array, target)                     \
+(@{                                                \
+  __label__ found;                                \
+  typeof (target) _SEARCH_target = (target);      \
+  typeof (*(array)) *_SEARCH_array = (array);     \
+  int i, j;                                       \
+  int value;                                      \
+  for (i = 0; i < max; i++)                       \
+    for (j = 0; j < max; j++)                     \
+      if (_SEARCH_array[i][j] == _SEARCH_target)  \
+        @{ value = i; goto found; @}                \
+  value = -1;                                     \
+ found:                                           \
+  value;                                          \
+@})
+@end example
+
+@node Labels as Values
+@section Labels as Values
+@cindex labels as values
+@cindex computed gotos
+@cindex goto with computed label
+@cindex address of a label
+
+You can get the address of a label defined in the current function
+(or a containing function) with the unary operator @samp{&&}.  The
+value has type @code{void *}.  This value is a constant and can be used
+wherever a constant of that type is valid.  For example:
+
+@example
+void *ptr;
+@dots{}
+ptr = &&foo;
+@end example
+
+To use these values, you need to be able to jump to one.  This is done
+with the computed goto statement@footnote{The analogous feature in
+Fortran is called an assigned goto, but that name seems inappropriate in
+C, where one can do more than simply store label addresses in label
+variables.}, @code{goto *@var{exp};}.  For example,
+
+@example
+goto *ptr;
+@end example
+
+@noindent
+Any expression of type @code{void *} is allowed.
+
+One way of using these constants is in initializing a static array that
+will serve as a jump table:
+
+@example
+static void *array[] = @{ &&foo, &&bar, &&hack @};
+@end example
+
+Then you can select a label with indexing, like this:
+
+@example
+goto *array[i];
+@end example
+
+@noindent
+Note that this does not check whether the subscript is in bounds---array
+indexing in C never does that.
+
+Such an array of label values serves a purpose much like that of the
+@code{switch} statement.  The @code{switch} statement is cleaner, so
+use that rather than an array unless the problem does not fit a
+@code{switch} statement very well.
+
+Another use of label values is in an interpreter for threaded code.
+The labels within the interpreter function can be stored in the
+threaded code for super-fast dispatching.
+
+You may not use this mechanism to jump to code in a different function.
+If you do that, totally unpredictable things will happen.  The best way to
+avoid this is to store the label address only in automatic variables and
+never pass it as an argument.
+
+An alternate way to write the above example is
+
+@example
+static const int array[] = @{ &&foo - &&foo, &&bar - &&foo,
+                             &&hack - &&foo @};
+goto *(&&foo + array[i]);
+@end example
+
+@noindent
+This is more friendly to code living in shared libraries, as it reduces
+the number of dynamic relocations that are needed, and by consequence,
+allows the data to be read-only.
+
+@node Nested Functions
+@section Nested Functions
+@cindex nested functions
+@cindex downward funargs
+@cindex thunks
+
+A @dfn{nested function} is a function defined inside another function.
+(Nested functions are not supported for GNU C++.)  The nested function's
+name is local to the block where it is defined.  For example, here we
+define a nested function named @code{square}, and call it twice:
+
+@example
+@group
+foo (double a, double b)
+@{
+  double square (double z) @{ return z * z; @}
+
+  return square (a) + square (b);
+@}
+@end group
+@end example
+
+The nested function can access all the variables of the containing
+function that are visible at the point of its definition.  This is
+called @dfn{lexical scoping}.  For example, here we show a nested
+function which uses an inherited variable named @code{offset}:
+
+@example
+@group
+bar (int *array, int offset, int size)
+@{
+  int access (int *array, int index)
+    @{ return array[index + offset]; @}
+  int i;
+  @dots{}
+  for (i = 0; i < size; i++)
+    @dots{} access (array, i) @dots{}
+@}
+@end group
+@end example
+
+Nested function definitions are permitted within functions in the places
+where variable definitions are allowed; that is, in any block, before
+the first statement in the block.
+
+It is possible to call the nested function from outside the scope of its
+name by storing its address or passing the address to another function:
+
+@example
+hack (int *array, int size)
+@{
+  void store (int index, int value)
+    @{ array[index] = value; @}
+
+  intermediate (store, size);
+@}
+@end example
+
+Here, the function @code{intermediate} receives the address of
+@code{store} as an argument.  If @code{intermediate} calls @code{store},
+the arguments given to @code{store} are used to store into @code{array}.
+But this technique works only so long as the containing function
+(@code{hack}, in this example) does not exit.
+
+If you try to call the nested function through its address after the
+containing function has exited, all hell will break loose.  If you try
+to call it after a containing scope level has exited, and if it refers
+to some of the variables that are no longer in scope, you may be lucky,
+but it's not wise to take the risk.  If, however, the nested function
+does not refer to anything that has gone out of scope, you should be
+safe.
+
+GCC implements taking the address of a nested function using a technique
+called @dfn{trampolines}.  A paper describing them is available as
+
+@noindent
+@uref{http://people.debian.org/~karlheg/Usenix88-lexic.pdf}.
+
+A nested function can jump to a label inherited from a containing
+function, provided the label was explicitly declared in the containing
+function (@pxref{Local Labels}).  Such a jump returns instantly to the
+containing function, exiting the nested function which did the
+@code{goto} and any intermediate functions as well.  Here is an example:
+
+@example
+@group
+bar (int *array, int offset, int size)
+@{
+  __label__ failure;
+  int access (int *array, int index)
+    @{
+      if (index > size)
+        goto failure;
+      return array[index + offset];
+    @}
+  int i;
+  @dots{}
+  for (i = 0; i < size; i++)
+    @dots{} access (array, i) @dots{}
+  @dots{}
+  return 0;
+
+ /* @r{Control comes here from @code{access}
+    if it detects an error.}  */
+ failure:
+  return -1;
+@}
+@end group
+@end example
+
+A nested function always has internal linkage.  Declaring one with
+@code{extern} is erroneous.  If you need to declare the nested function
+before its definition, use @code{auto} (which is otherwise meaningless
+for function declarations).
+
+@example
+bar (int *array, int offset, int size)
+@{
+  __label__ failure;
+  auto int access (int *, int);
+  @dots{}
+  int access (int *array, int index)
+    @{
+      if (index > size)
+        goto failure;
+      return array[index + offset];
+    @}
+  @dots{}
+@}
+@end example
+
+@node Constructing Calls
+@section Constructing Function Calls
+@cindex constructing calls
+@cindex forwarding calls
+
+Using the built-in functions described below, you can record
+the arguments a function received, and call another function
+with the same arguments, without knowing the number or types
+of the arguments.
+
+You can also record the return value of that function call,
+and later return that value, without knowing what data type
+the function tried to return (as long as your caller expects
+that data type).
+
+@deftypefn {Built-in Function} {void *} __builtin_apply_args ()
+This built-in function returns a pointer to data
+describing how to perform a call with the same arguments as were passed
+to the current function.
+
+The function saves the arg pointer register, structure value address,
+and all registers that might be used to pass arguments to a function
+into a block of memory allocated on the stack.  Then it returns the
+address of that block.
+@end deftypefn
+
+@deftypefn {Built-in Function} {void *} __builtin_apply (void (*@var{function})(), void *@var{arguments}, size_t @var{size})
+This built-in function invokes @var{function}
+with a copy of the parameters described by @var{arguments}
+and @var{size}.
+
+The value of @var{arguments} should be the value returned by
+@code{__builtin_apply_args}.  The argument @var{size} specifies the size
+of the stack argument data, in bytes.
+
+This function returns a pointer to data describing
+how to return whatever value was returned by @var{function}.  The data
+is saved in a block of memory allocated on the stack.
+
+It is not always simple to compute the proper value for @var{size}.  The
+value is used by @code{__builtin_apply} to compute the amount of data
+that should be pushed on the stack and copied from the incoming argument
+area.
+@end deftypefn
+
+@deftypefn {Built-in Function} {void} __builtin_return (void *@var{result})
+This built-in function returns the value described by @var{result} from
+the containing function.  You should specify, for @var{result}, a value
+returned by @code{__builtin_apply}.
+@end deftypefn
+
+@node Naming Types
+@section Naming an Expression's Type
+@cindex naming types
+
+You can give a name to the type of an expression using a @code{typedef}
+declaration with an initializer.  Here is how to define @var{name} as a
+type name for the type of @var{exp}:
+
+@example
+typedef @var{name} = @var{exp};
+@end example
+
+This is useful in conjunction with the statements-within-expressions
+feature.  Here is how the two together can be used to define a safe
+``maximum'' macro that operates on any arithmetic type:
+
+@example
+#define max(a,b) \
+  (@{typedef _ta = (a), _tb = (b);  \
+    _ta _a = (a); _tb _b = (b);     \
+    _a > _b ? _a : _b; @})
+@end example
+
+@cindex underscores in variables in macros
+@cindex @samp{_} in variables in macros
+@cindex local variables in macros
+@cindex variables, local, in macros
+@cindex macros, local variables in
+
+The reason for using names that start with underscores for the local
+variables is to avoid conflicts with variable names that occur within the
+expressions that are substituted for @code{a} and @code{b}.  Eventually we
+hope to design a new form of declaration syntax that allows you to declare
+variables whose scopes start only after their initializers; this will be a
+more reliable way to prevent such conflicts.
+
+@node Typeof
+@section Referring to a Type with @code{typeof}
+@findex typeof
+@findex sizeof
+@cindex macros, types of arguments
+
+Another way to refer to the type of an expression is with @code{typeof}.
+The syntax of using of this keyword looks like @code{sizeof}, but the
+construct acts semantically like a type name defined with @code{typedef}.
+
+There are two ways of writing the argument to @code{typeof}: with an
+expression or with a type.  Here is an example with an expression:
+
+@example
+typeof (x[0](1))
+@end example
+
+@noindent
+This assumes that @code{x} is an array of pointers to functions;
+the type described is that of the values of the functions.
+
+Here is an example with a typename as the argument:
+
+@example
+typeof (int *)
+@end example
+
+@noindent
+Here the type described is that of pointers to @code{int}.
+
+If you are writing a header file that must work when included in ISO C
+programs, write @code{__typeof__} instead of @code{typeof}.
+@xref{Alternate Keywords}.
+
+A @code{typeof}-construct can be used anywhere a typedef name could be
+used.  For example, you can use it in a declaration, in a cast, or inside
+of @code{sizeof} or @code{typeof}.
+
+@itemize @bullet
+@item
+This declares @code{y} with the type of what @code{x} points to.
+
+@example
+typeof (*x) y;
+@end example
+
+@item
+This declares @code{y} as an array of such values.
+
+@example
+typeof (*x) y[4];
+@end example
+
+@item
+This declares @code{y} as an array of pointers to characters:
+
+@example
+typeof (typeof (char *)[4]) y;
+@end example
+
+@noindent
+It is equivalent to the following traditional C declaration:
+
+@example
+char *y[4];
+@end example
+
+To see the meaning of the declaration using @code{typeof}, and why it
+might be a useful way to write, let's rewrite it with these macros:
+
+@example
+#define pointer(T)  typeof(T *)
+#define array(T, N) typeof(T [N])
+@end example
+
+@noindent
+Now the declaration can be rewritten this way:
+
+@example
+array (pointer (char), 4) y;
+@end example
+
+@noindent
+Thus, @code{array (pointer (char), 4)} is the type of arrays of 4
+pointers to @code{char}.
+@end itemize
+
+@node Lvalues
+@section Generalized Lvalues
+@cindex compound expressions as lvalues
+@cindex expressions, compound, as lvalues
+@cindex conditional expressions as lvalues
+@cindex expressions, conditional, as lvalues
+@cindex casts as lvalues
+@cindex generalized lvalues
+@cindex lvalues, generalized
+@cindex extensions, @code{?:}
+@cindex @code{?:} extensions
+Compound expressions, conditional expressions and casts are allowed as
+lvalues provided their operands are lvalues.  This means that you can take
+their addresses or store values into them.
+
+Standard C++ allows compound expressions and conditional expressions as
+lvalues, and permits casts to reference type, so use of this extension
+is deprecated for C++ code.
+
+For example, a compound expression can be assigned, provided the last
+expression in the sequence is an lvalue.  These two expressions are
+equivalent:
+
+@example
+(a, b) += 5
+a, (b += 5)
+@end example
+
+Similarly, the address of the compound expression can be taken.  These two
+expressions are equivalent:
+
+@example
+&(a, b)
+a, &b
+@end example
+
+A conditional expression is a valid lvalue if its type is not void and the
+true and false branches are both valid lvalues.  For example, these two
+expressions are equivalent:
+
+@example
+(a ? b : c) = 5
+(a ? b = 5 : (c = 5))
+@end example
+
+A cast is a valid lvalue if its operand is an lvalue.  A simple
+assignment whose left-hand side is a cast works by converting the
+right-hand side first to the specified type, then to the type of the
+inner left-hand side expression.  After this is stored, the value is
+converted back to the specified type to become the value of the
+assignment.  Thus, if @code{a} has type @code{char *}, the following two
+expressions are equivalent:
+
+@example
+(int)a = 5
+(int)(a = (char *)(int)5)
+@end example
+
+An assignment-with-arithmetic operation such as @samp{+=} applied to a cast
+performs the arithmetic using the type resulting from the cast, and then
+continues as in the previous case.  Therefore, these two expressions are
+equivalent:
+
+@example
+(int)a += 5
+(int)(a = (char *)(int) ((int)a + 5))
+@end example
+
+You cannot take the address of an lvalue cast, because the use of its
+address would not work out coherently.  Suppose that @code{&(int)f} were
+permitted, where @code{f} has type @code{float}.  Then the following
+statement would try to store an integer bit-pattern where a floating
+point number belongs:
+
+@example
+*&(int)f = 1;
+@end example
+
+This is quite different from what @code{(int)f = 1} would do---that
+would convert 1 to floating point and store it.  Rather than cause this
+inconsistency, we think it is better to prohibit use of @samp{&} on a cast.
+
+If you really do want an @code{int *} pointer with the address of
+@code{f}, you can simply write @code{(int *)&f}.
+
+@node Conditionals
+@section Conditionals with Omitted Operands
+@cindex conditional expressions, extensions
+@cindex omitted middle-operands
+@cindex middle-operands, omitted
+@cindex extensions, @code{?:}
+@cindex @code{?:} extensions
+
+The middle operand in a conditional expression may be omitted.  Then
+if the first operand is nonzero, its value is the value of the conditional
+expression.
+
+Therefore, the expression
+
+@example
+x ? : y
+@end example
+
+@noindent
+has the value of @code{x} if that is nonzero; otherwise, the value of
+@code{y}.
+
+This example is perfectly equivalent to
+
+@example
+x ? x : y
+@end example
+
+@cindex side effect in ?:
+@cindex ?: side effect
+@noindent
+In this simple case, the ability to omit the middle operand is not
+especially useful.  When it becomes useful is when the first operand does,
+or may (if it is a macro argument), contain a side effect.  Then repeating
+the operand in the middle would perform the side effect twice.  Omitting
+the middle operand uses the value already computed without the undesirable
+effects of recomputing it.
+
+@node Long Long
+@section Double-Word Integers
+@cindex @code{long long} data types
+@cindex double-word arithmetic
+@cindex multiprecision arithmetic
+@cindex @code{LL} integer suffix
+@cindex @code{ULL} integer suffix
+
+ISO C99 supports data types for integers that are at least 64 bits wide,
+and as an extension GCC supports them in C89 mode and in C++.
+Simply write @code{long long int} for a signed integer, or
+@code{unsigned long long int} for an unsigned integer.  To make an
+integer constant of type @code{long long int}, add the suffix @samp{LL}
+to the integer.  To make an integer constant of type @code{unsigned long
+long int}, add the suffix @samp{ULL} to the integer.
+
+You can use these types in arithmetic like any other integer types.
+Addition, subtraction, and bitwise boolean operations on these types
+are open-coded on all types of machines.  Multiplication is open-coded
+if the machine supports fullword-to-doubleword a widening multiply
+instruction.  Division and shifts are open-coded only on machines that
+provide special support.  The operations that are not open-coded use
+special library routines that come with GCC@.
+
+There may be pitfalls when you use @code{long long} types for function
+arguments, unless you declare function prototypes.  If a function
+expects type @code{int} for its argument, and you pass a value of type
+@code{long long int}, confusion will result because the caller and the
+subroutine will disagree about the number of bytes for the argument.
+Likewise, if the function expects @code{long long int} and you pass
+@code{int}.  The best way to avoid such problems is to use prototypes.
+
+@node Complex
+@section Complex Numbers
+@cindex complex numbers
+@cindex @code{_Complex} keyword
+@cindex @code{__complex__} keyword
+
+ISO C99 supports complex floating data types, and as an extension GCC
+supports them in C89 mode and in C++, and supports complex integer data
+types which are not part of ISO C99.  You can declare complex types
+using the keyword @code{_Complex}.  As an extension, the older GNU
+keyword @code{__complex__} is also supported.
+
+For example, @samp{_Complex double x;} declares @code{x} as a
+variable whose real part and imaginary part are both of type
+@code{double}.  @samp{_Complex short int y;} declares @code{y} to
+have real and imaginary parts of type @code{short int}; this is not
+likely to be useful, but it shows that the set of complex types is
+complete.
+
+To write a constant with a complex data type, use the suffix @samp{i} or
+@samp{j} (either one; they are equivalent).  For example, @code{2.5fi}
+has type @code{_Complex float} and @code{3i} has type
+@code{_Complex int}.  Such a constant always has a pure imaginary
+value, but you can form any complex value you like by adding one to a
+real constant.  This is a GNU extension; if you have an ISO C99
+conforming C library (such as GNU libc), and want to construct complex
+constants of floating type, you should include @code{<complex.h>} and
+use the macros @code{I} or @code{_Complex_I} instead.
+
+@cindex @code{__real__} keyword
+@cindex @code{__imag__} keyword
+To extract the real part of a complex-valued expression @var{exp}, write
+@code{__real__ @var{exp}}.  Likewise, use @code{__imag__} to
+extract the imaginary part.  This is a GNU extension; for values of
+floating type, you should use the ISO C99 functions @code{crealf},
+@code{creal}, @code{creall}, @code{cimagf}, @code{cimag} and
+@code{cimagl}, declared in @code{<complex.h>} and also provided as
+built-in functions by GCC@.
+
+@cindex complex conjugation
+The operator @samp{~} performs complex conjugation when used on a value
+with a complex type.  This is a GNU extension; for values of
+floating type, you should use the ISO C99 functions @code{conjf},
+@code{conj} and @code{conjl}, declared in @code{<complex.h>} and also
+provided as built-in functions by GCC@.
+
+GCC can allocate complex automatic variables in a noncontiguous
+fashion; it's even possible for the real part to be in a register while
+the imaginary part is on the stack (or vice-versa).  None of the
+supported debugging info formats has a way to represent noncontiguous
+allocation like this, so GCC describes a noncontiguous complex
+variable as if it were two separate variables of noncomplex type.
+If the variable's actual name is @code{foo}, the two fictitious
+variables are named @code{foo$real} and @code{foo$imag}.  You can
+examine and set these two fictitious variables with your debugger.
+
+A future version of GDB will know how to recognize such pairs and treat
+them as a single variable with a complex type.
+
+@node Hex Floats
+@section Hex Floats
+@cindex hex floats
+
+ISO C99 supports floating-point numbers written not only in the usual
+decimal notation, such as @code{1.55e1}, but also numbers such as
+@code{0x1.fp3} written in hexadecimal format.  As a GNU extension, GCC
+supports this in C89 mode (except in some cases when strictly
+conforming) and in C++.  In that format the
+@samp{0x} hex introducer and the @samp{p} or @samp{P} exponent field are
+mandatory.  The exponent is a decimal number that indicates the power of
+2 by which the significant part will be multiplied.  Thus @samp{0x1.f} is
+@tex
+$1 {15\over16}$,
+@end tex
+@ifnottex
+1 15/16,
+@end ifnottex
+@samp{p3} multiplies it by 8, and the value of @code{0x1.fp3}
+is the same as @code{1.55e1}.
+
+Unlike for floating-point numbers in the decimal notation the exponent
+is always required in the hexadecimal notation.  Otherwise the compiler
+would not be able to resolve the ambiguity of, e.g., @code{0x1.f}.  This
+could mean @code{1.0f} or @code{1.9375} since @samp{f} is also the
+extension for floating-point constants of type @code{float}.
+
+@node Zero Length
+@section Arrays of Length Zero
+@cindex arrays of length zero
+@cindex zero-length arrays
+@cindex length-zero arrays
+@cindex flexible array members
+
+Zero-length arrays are allowed in GNU C@.  They are very useful as the
+last element of a structure which is really a header for a variable-length
+object:
+
+@example
+struct line @{
+  int length;
+  char contents[0];
+@};
+
+struct line *thisline = (struct line *)
+  malloc (sizeof (struct line) + this_length);
+thisline->length = this_length;
+@end example
+
+In ISO C89, you would have to give @code{contents} a length of 1, which
+means either you waste space or complicate the argument to @code{malloc}.
+
+In ISO C99, you would use a @dfn{flexible array member}, which is
+slightly different in syntax and semantics:
+
+@itemize @bullet
+@item
+Flexible array members are written as @code{contents[]} without
+the @code{0}.
+
+@item
+Flexible array members have incomplete type, and so the @code{sizeof}
+operator may not be applied.  As a quirk of the original implementation
+of zero-length arrays, @code{sizeof} evaluates to zero.
+
+@item
+Flexible array members may only appear as the last member of a
+@code{struct} that is otherwise non-empty.
+@end itemize
+
+GCC versions before 3.0 allowed zero-length arrays to be statically
+initialized, as if they were flexible arrays.  In addition to those
+cases that were useful, it also allowed initializations in situations
+that would corrupt later data.  Non-empty initialization of zero-length
+arrays is now treated like any case where there are more initializer
+elements than the array holds, in that a suitable warning about "excess
+elements in array" is given, and the excess elements (all of them, in
+this case) are ignored.
+
+Instead GCC allows static initialization of flexible array members.
+This is equivalent to defining a new structure containing the original
+structure followed by an array of sufficient size to contain the data.
+I.e.@: in the following, @code{f1} is constructed as if it were declared
+like @code{f2}.
+
+@example
+struct f1 @{
+  int x; int y[];
+@} f1 = @{ 1, @{ 2, 3, 4 @} @};
+
+struct f2 @{
+  struct f1 f1; int data[3];
+@} f2 = @{ @{ 1 @}, @{ 2, 3, 4 @} @};
+@end example
+
+@noindent
+The convenience of this extension is that @code{f1} has the desired
+type, eliminating the need to consistently refer to @code{f2.f1}.
+
+This has symmetry with normal static arrays, in that an array of
+unknown size is also written with @code{[]}.
+
+Of course, this extension only makes sense if the extra data comes at
+the end of a top-level object, as otherwise we would be overwriting
+data at subsequent offsets.  To avoid undue complication and confusion
+with initialization of deeply nested arrays, we simply disallow any
+non-empty initialization except when the structure is the top-level
+object.  For example:
+
+@example
+struct foo @{ int x; int y[]; @};
+struct bar @{ struct foo z; @};
+
+struct foo a = @{ 1, @{ 2, 3, 4 @} @};        // @r{Valid.}
+struct bar b = @{ @{ 1, @{ 2, 3, 4 @} @} @};    // @r{Invalid.}
+struct bar c = @{ @{ 1, @{ @} @} @};            // @r{Valid.}
+struct foo d[1] = @{ @{ 1 @{ 2, 3, 4 @} @} @};  // @r{Invalid.}
+@end example
+
+@node Variable Length
+@section Arrays of Variable Length
+@cindex variable-length arrays
+@cindex arrays of variable length
+@cindex VLAs
+
+Variable-length automatic arrays are allowed in ISO C99, and as an
+extension GCC accepts them in C89 mode and in C++.  (However, GCC's
+implementation of variable-length arrays does not yet conform in detail
+to the ISO C99 standard.)  These arrays are
+declared like any other automatic arrays, but with a length that is not
+a constant expression.  The storage is allocated at the point of
+declaration and deallocated when the brace-level is exited.  For
+example:
+
+@example
+FILE *
+concat_fopen (char *s1, char *s2, char *mode)
+@{
+  char str[strlen (s1) + strlen (s2) + 1];
+  strcpy (str, s1);
+  strcat (str, s2);
+  return fopen (str, mode);
+@}
+@end example
+
+@cindex scope of a variable length array
+@cindex variable-length array scope
+@cindex deallocating variable length arrays
+Jumping or breaking out of the scope of the array name deallocates the
+storage.  Jumping into the scope is not allowed; you get an error
+message for it.
+
+@cindex @code{alloca} vs variable-length arrays
+You can use the function @code{alloca} to get an effect much like
+variable-length arrays.  The function @code{alloca} is available in
+many other C implementations (but not in all).  On the other hand,
+variable-length arrays are more elegant.
+
+There are other differences between these two methods.  Space allocated
+with @code{alloca} exists until the containing @emph{function} returns.
+The space for a variable-length array is deallocated as soon as the array
+name's scope ends.  (If you use both variable-length arrays and
+@code{alloca} in the same function, deallocation of a variable-length array
+will also deallocate anything more recently allocated with @code{alloca}.)
+
+You can also use variable-length arrays as arguments to functions:
+
+@example
+struct entry
+tester (int len, char data[len][len])
+@{
+  @dots{}
+@}
+@end example
+
+The length of an array is computed once when the storage is allocated
+and is remembered for the scope of the array in case you access it with
+@code{sizeof}.
+
+If you want to pass the array first and the length afterward, you can
+use a forward declaration in the parameter list---another GNU extension.
+
+@example
+struct entry
+tester (int len; char data[len][len], int len)
+@{
+  @dots{}
+@}
+@end example
+
+@cindex parameter forward declaration
+The @samp{int len} before the semicolon is a @dfn{parameter forward
+declaration}, and it serves the purpose of making the name @code{len}
+known when the declaration of @code{data} is parsed.
+
+You can write any number of such parameter forward declarations in the
+parameter list.  They can be separated by commas or semicolons, but the
+last one must end with a semicolon, which is followed by the ``real''
+parameter declarations.  Each forward declaration must match a ``real''
+declaration in parameter name and data type.  ISO C99 does not support
+parameter forward declarations.
+
+@node Variadic Macros
+@section Macros with a Variable Number of Arguments.
+@cindex variable number of arguments
+@cindex macro with variable arguments
+@cindex rest argument (in macro)
+@cindex variadic macros
+
+In the ISO C standard of 1999, a macro can be declared to accept a
+variable number of arguments much as a function can.  The syntax for
+defining the macro is similar to that of a function.  Here is an
+example:
+
+@example
+#define debug(format, ...) fprintf (stderr, format, __VA_ARGS__)
+@end example
+
+Here @samp{@dots{}} is a @dfn{variable argument}.  In the invocation of
+such a macro, it represents the zero or more tokens until the closing
+parenthesis that ends the invocation, including any commas.  This set of
+tokens replaces the identifier @code{__VA_ARGS__} in the macro body
+wherever it appears.  See the CPP manual for more information.
+
+GCC has long supported variadic macros, and used a different syntax that
+allowed you to give a name to the variable arguments just like any other
+argument.  Here is an example:
+
+@example
+#define debug(format, args...) fprintf (stderr, format, args)
+@end example
+
+This is in all ways equivalent to the ISO C example above, but arguably
+more readable and descriptive.
+
+GNU CPP has two further variadic macro extensions, and permits them to
+be used with either of the above forms of macro definition.
+
+In standard C, you are not allowed to leave the variable argument out
+entirely; but you are allowed to pass an empty argument.  For example,
+this invocation is invalid in ISO C, because there is no comma after
+the string:
+
+@example
+debug ("A message")
+@end example
+
+GNU CPP permits you to completely omit the variable arguments in this
+way.  In the above examples, the compiler would complain, though since
+the expansion of the macro still has the extra comma after the format
+string.
+
+To help solve this problem, CPP behaves specially for variable arguments
+used with the token paste operator, @samp{##}.  If instead you write
+
+@example
+#define debug(format, ...) fprintf (stderr, format, ## __VA_ARGS__)
+@end example
+
+and if the variable arguments are omitted or empty, the @samp{##}
+operator causes the preprocessor to remove the comma before it.  If you
+do provide some variable arguments in your macro invocation, GNU CPP
+does not complain about the paste operation and instead places the
+variable arguments after the comma.  Just like any other pasted macro
+argument, these arguments are not macro expanded.
+
+@node Escaped Newlines
+@section Slightly Looser Rules for Escaped Newlines
+@cindex escaped newlines
+@cindex newlines (escaped)
+
+Recently, the non-traditional preprocessor has relaxed its treatment of
+escaped newlines.  Previously, the newline had to immediately follow a
+backslash.  The current implementation allows whitespace in the form of
+spaces, horizontal and vertical tabs, and form feeds between the
+backslash and the subsequent newline.  The preprocessor issues a
+warning, but treats it as a valid escaped newline and combines the two
+lines to form a single logical line.  This works within comments and
+tokens, including multi-line strings, as well as between tokens.
+Comments are @emph{not} treated as whitespace for the purposes of this
+relaxation, since they have not yet been replaced with spaces.
+
+@node Multi-line Strings
+@section String Literals with Embedded Newlines
+@cindex multi-line string literals
+
+As an extension, GNU CPP permits string literals to cross multiple lines
+without escaping the embedded newlines.  Each embedded newline is
+replaced with a single @samp{\n} character in the resulting string
+literal, regardless of what form the newline took originally.
+
+CPP currently allows such strings in directives as well (other than the
+@samp{#include} family).  This is deprecated and will eventually be
+removed.
+
+@node Subscripting
+@section Non-Lvalue Arrays May Have Subscripts
+@cindex subscripting
+@cindex arrays, non-lvalue
+
+@cindex subscripting and function values
+In ISO C99, arrays that are not lvalues still decay to pointers, and
+may be subscripted, although they may not be modified or used after
+the next sequence point and the unary @samp{&} operator may not be
+applied to them.  As an extension, GCC allows such arrays to be
+subscripted in C89 mode, though otherwise they do not decay to
+pointers outside C99 mode.  For example,
+this is valid in GNU C though not valid in C89:
+
+@example
+@group
+struct foo @{int a[4];@};
+
+struct foo f();
+
+bar (int index)
+@{
+  return f().a[index];
+@}
+@end group
+@end example
+
+@node Pointer Arith
+@section Arithmetic on @code{void}- and Function-Pointers
+@cindex void pointers, arithmetic
+@cindex void, size of pointer to
+@cindex function pointers, arithmetic
+@cindex function, size of pointer to
+
+In GNU C, addition and subtraction operations are supported on pointers to
+@code{void} and on pointers to functions.  This is done by treating the
+size of a @code{void} or of a function as 1.
+
+A consequence of this is that @code{sizeof} is also allowed on @code{void}
+and on function types, and returns 1.
+
+@opindex Wpointer-arith
+The option @option{-Wpointer-arith} requests a warning if these extensions
+are used.
+
+@node Initializers
+@section Non-Constant Initializers
+@cindex initializers, non-constant
+@cindex non-constant initializers
+
+As in standard C++ and ISO C99, the elements of an aggregate initializer for an
+automatic variable are not required to be constant expressions in GNU C@.
+Here is an example of an initializer with run-time varying elements:
+
+@example
+foo (float f, float g)
+@{
+  float beat_freqs[2] = @{ f-g, f+g @};
+  @dots{}
+@}
+@end example
+
+@node Compound Literals
+@section Compound Literals
+@cindex constructor expressions
+@cindex initializations in expressions
+@cindex structures, constructor expression
+@cindex expressions, constructor
+@cindex compound literals
+@c The GNU C name for what C99 calls compound literals was "constructor expressions".
+
+ISO C99 supports compound literals.  A compound literal looks like
+a cast containing an initializer.  Its value is an object of the
+type specified in the cast, containing the elements specified in
+the initializer; it is an lvalue.  As an extension, GCC supports
+compound literals in C89 mode and in C++.
+
+Usually, the specified type is a structure.  Assume that
+@code{struct foo} and @code{structure} are declared as shown:
+
+@example
+struct foo @{int a; char b[2];@} structure;
+@end example
+
+@noindent
+Here is an example of constructing a @code{struct foo} with a compound literal:
+
+@example
+structure = ((struct foo) @{x + y, 'a', 0@});
+@end example
+
+@noindent
+This is equivalent to writing the following:
+
+@example
+@{
+  struct foo temp = @{x + y, 'a', 0@};
+  structure = temp;
+@}
+@end example
+
+You can also construct an array.  If all the elements of the compound literal
+are (made up of) simple constant expressions, suitable for use in
+initializers of objects of static storage duration, then the compound
+literal can be coerced to a pointer to its first element and used in
+such an initializer, as shown here:
+
+@example
+char **foo = (char *[]) @{ "x", "y", "z" @};
+@end example
+
+Compound literals for scalar types and union types are is
+also allowed, but then the compound literal is equivalent
+to a cast.
+
+As a GNU extension, GCC allows initialization of objects with static storage
+duration by compound literals (which is not possible in ISO C99, because
+the initializer is not a constant).
+It is handled as if the object was initialized only with the bracket
+enclosed list if compound literal's and object types match.
+The initializer list of the compound literal must be constant.
+If the object being initialized has array type of unknown size, the size is
+determined by compound literal size.
+
+@example
+static struct foo x = (struct foo) @{1, 'a', 'b'@};
+static int y[] = (int []) @{1, 2, 3@};
+static int z[] = (int [3]) @{1@};
+@end example
+
+@noindent
+The above lines are equivalent to the following:
+@example
+static struct foo x = @{1, 'a', 'b'@};
+static int y[] = @{1, 2, 3@};
+static int z[] = @{1, 0, 0@};
+@end example
+
+@node Designated Inits
+@section Designated Initializers
+@cindex initializers with labeled elements
+@cindex labeled elements in initializers
+@cindex case labels in initializers
+@cindex designated initializers
+
+Standard C89 requires the elements of an initializer to appear in a fixed
+order, the same as the order of the elements in the array or structure
+being initialized.
+
+In ISO C99 you can give the elements in any order, specifying the array
+indices or structure field names they apply to, and GNU C allows this as
+an extension in C89 mode as well.  This extension is not
+implemented in GNU C++.
+
+To specify an array index, write
+@samp{[@var{index}] =} before the element value.  For example,
+
+@example
+int a[6] = @{ [4] = 29, [2] = 15 @};
+@end example
+
+@noindent
+is equivalent to
+
+@example
+int a[6] = @{ 0, 0, 15, 0, 29, 0 @};
+@end example
+
+@noindent
+The index values must be constant expressions, even if the array being
+initialized is automatic.
+
+An alternative syntax for this which has been obsolete since GCC 2.5 but
+GCC still accepts is to write @samp{[@var{index}]} before the element
+value, with no @samp{=}.
+
+To initialize a range of elements to the same value, write
+@samp{[@var{first} ... @var{last}] = @var{value}}.  This is a GNU
+extension.  For example,
+
+@example
+int widths[] = @{ [0 ... 9] = 1, [10 ... 99] = 2, [100] = 3 @};
+@end example
+
+@noindent
+If the value in it has side-effects, the side-effects will happen only once,
+not for each initialized field by the range initializer.
+
+@noindent
+Note that the length of the array is the highest value specified
+plus one.
+
+In a structure initializer, specify the name of a field to initialize
+with @samp{.@var{fieldname} =} before the element value.  For example,
+given the following structure,
+
+@example
+struct point @{ int x, y; @};
+@end example
+
+@noindent
+the following initialization
+
+@example
+struct point p = @{ .y = yvalue, .x = xvalue @};
+@end example
+
+@noindent
+is equivalent to
+
+@example
+struct point p = @{ xvalue, yvalue @};
+@end example
+
+Another syntax which has the same meaning, obsolete since GCC 2.5, is
+@samp{@var{fieldname}:}, as shown here:
+
+@example
+struct point p = @{ y: yvalue, x: xvalue @};
+@end example
+
+@cindex designators
+The @samp{[@var{index}]} or @samp{.@var{fieldname}} is known as a
+@dfn{designator}.  You can also use a designator (or the obsolete colon
+syntax) when initializing a union, to specify which element of the union
+should be used.  For example,
+
+@example
+union foo @{ int i; double d; @};
+
+union foo f = @{ .d = 4 @};
+@end example
+
+@noindent
+will convert 4 to a @code{double} to store it in the union using
+the second element.  By contrast, casting 4 to type @code{union foo}
+would store it into the union as the integer @code{i}, since it is
+an integer.  (@xref{Cast to Union}.)
+
+You can combine this technique of naming elements with ordinary C
+initialization of successive elements.  Each initializer element that
+does not have a designator applies to the next consecutive element of the
+array or structure.  For example,
+
+@example
+int a[6] = @{ [1] = v1, v2, [4] = v4 @};
+@end example
+
+@noindent
+is equivalent to
+
+@example
+int a[6] = @{ 0, v1, v2, 0, v4, 0 @};
+@end example
+
+Labeling the elements of an array initializer is especially useful
+when the indices are characters or belong to an @code{enum} type.
+For example:
+
+@example
+int whitespace[256]
+  = @{ [' '] = 1, ['\t'] = 1, ['\h'] = 1,
+      ['\f'] = 1, ['\n'] = 1, ['\r'] = 1 @};
+@end example
+
+@cindex designator lists
+You can also write a series of @samp{.@var{fieldname}} and
+@samp{[@var{index}]} designators before an @samp{=} to specify a
+nested subobject to initialize; the list is taken relative to the
+subobject corresponding to the closest surrounding brace pair.  For
+example, with the @samp{struct point} declaration above:
+
+@example
+struct point ptarray[10] = @{ [2].y = yv2, [2].x = xv2, [0].x = xv0 @};
+@end example
+
+@noindent
+If the same field is initialized multiple times, it will have value from
+the last initialization.  If any such overridden initialization has
+side-effect, it is unspecified whether the side-effect happens or not.
+Currently, gcc will discard them and issue a warning.
+
+@node Case Ranges
+@section Case Ranges
+@cindex case ranges
+@cindex ranges in case statements
+
+You can specify a range of consecutive values in a single @code{case} label,
+like this:
+
+@example
+case @var{low} ... @var{high}:
+@end example
+
+@noindent
+This has the same effect as the proper number of individual @code{case}
+labels, one for each integer value from @var{low} to @var{high}, inclusive.
+
+This feature is especially useful for ranges of ASCII character codes:
+
+@example
+case 'A' ... 'Z':
+@end example
+
+@strong{Be careful:} Write spaces around the @code{...}, for otherwise
+it may be parsed wrong when you use it with integer values.  For example,
+write this:
+
+@example
+case 1 ... 5:
+@end example
+
+@noindent
+rather than this:
+
+@example
+case 1...5:
+@end example
+
+@node Cast to Union
+@section Cast to a Union Type
+@cindex cast to a union
+@cindex union, casting to a
+
+A cast to union type is similar to other casts, except that the type
+specified is a union type.  You can specify the type either with
+@code{union @var{tag}} or with a typedef name.  A cast to union is actually
+a constructor though, not a cast, and hence does not yield an lvalue like
+normal casts.  (@xref{Compound Literals}.)
+
+The types that may be cast to the union type are those of the members
+of the union.  Thus, given the following union and variables:
+
+@example
+union foo @{ int i; double d; @};
+int x;
+double y;
+@end example
+
+@noindent
+both @code{x} and @code{y} can be cast to type @code{union foo}.
+
+Using the cast as the right-hand side of an assignment to a variable of
+union type is equivalent to storing in a member of the union:
+
+@example
+union foo u;
+@dots{}
+u = (union foo) x  @equiv{}  u.i = x
+u = (union foo) y  @equiv{}  u.d = y
+@end example
+
+You can also use the union cast as a function argument:
+
+@example
+void hack (union foo);
+@dots{}
+hack ((union foo) x);
+@end example
+
+@node Mixed Declarations
+@section Mixed Declarations and Code
+@cindex mixed declarations and code
+@cindex declarations, mixed with code
+@cindex code, mixed with declarations
+
+ISO C99 and ISO C++ allow declarations and code to be freely mixed
+within compound statements.  As an extension, GCC also allows this in
+C89 mode.  For example, you could do:
+
+@example
+int i;
+@dots{}
+i++;
+int j = i + 2;
+@end example
+
+Each identifier is visible from where it is declared until the end of
+the enclosing block.
+
+@node Function Attributes
+@section Declaring Attributes of Functions
+@cindex function attributes
+@cindex declaring attributes of functions
+@cindex functions that never return
+@cindex functions that have no side effects
+@cindex functions in arbitrary sections
+@cindex functions that behave like malloc
+@cindex @code{volatile} applied to function
+@cindex @code{const} applied to function
+@cindex functions with @code{printf}, @code{scanf}, @code{strftime} or @code{strfmon} style arguments
+@cindex functions that are passed arguments in registers on the 386
+@cindex functions that pop the argument stack on the 386
+@cindex functions that do not pop the argument stack on the 386
+
+In GNU C, you declare certain things about functions called in your program
+which help the compiler optimize function calls and check your code more
+carefully.
+
+The keyword @code{__attribute__} allows you to specify special
+attributes when making a declaration.  This keyword is followed by an
+attribute specification inside double parentheses.  The following
+attributes are currently defined for functions on all targets:
+@code{noreturn}, @code{noinline}, @code{pure}, @code{const},
+@code{format}, @code{format_arg}, @code{no_instrument_function},
+@code{section}, @code{constructor}, @code{destructor}, @code{used},
+@code{unused}, @code{deprecated}, @code{weak}, @code{malloc}, and
+@code{alias}.  Several other attributes are defined for functions on
+particular target systems.  Other attributes, including @code{section}
+are supported for variables declarations (@pxref{Variable Attributes})
+and for types (@pxref{Type Attributes}).
+
+You may also specify attributes with @samp{__} preceding and following
+each keyword.  This allows you to use them in header files without
+being concerned about a possible macro of the same name.  For example,
+you may use @code{__noreturn__} instead of @code{noreturn}.
+
+@xref{Attribute Syntax}, for details of the exact syntax for using
+attributes.
+
+@table @code
+@cindex @code{noreturn} function attribute
+@item noreturn
+A few standard library functions, such as @code{abort} and @code{exit},
+cannot return.  GCC knows this automatically.  Some programs define
+their own functions that never return.  You can declare them
+@code{noreturn} to tell the compiler this fact.  For example,
+
+@smallexample
+@group
+void fatal () __attribute__ ((noreturn));
+
+void
+fatal (@dots{})
+@{
+  @dots{} /* @r{Print error message.} */ @dots{}
+  exit (1);
+@}
+@end group
+@end smallexample
+
+The @code{noreturn} keyword tells the compiler to assume that
+@code{fatal} cannot return.  It can then optimize without regard to what
+would happen if @code{fatal} ever did return.  This makes slightly
+better code.  More importantly, it helps avoid spurious warnings of
+uninitialized variables.
+
+Do not assume that registers saved by the calling function are
+restored before calling the @code{noreturn} function.
+
+It does not make sense for a @code{noreturn} function to have a return
+type other than @code{void}.
+
+The attribute @code{noreturn} is not implemented in GCC versions
+earlier than 2.5.  An alternative way to declare that a function does
+not return, which works in the current version and in some older
+versions, is as follows:
+
+@smallexample
+typedef void voidfn ();
+
+volatile voidfn fatal;
+@end smallexample
+
+@cindex @code{noinline} function attribute
+@item noinline
+This function attribute prevents a function from being considered for
+inlining.
+
+@cindex @code{pure} function attribute
+@item pure
+Many functions have no effects except the return value and their
+return value depends only on the parameters and/or global variables.
+Such a function can be subject
+to common subexpression elimination and loop optimization just as an
+arithmetic operator would be.  These functions should be declared
+with the attribute @code{pure}.  For example,
+
+@smallexample
+int square (int) __attribute__ ((pure));
+@end smallexample
+
+@noindent
+says that the hypothetical function @code{square} is safe to call
+fewer times than the program says.
+
+Some of common examples of pure functions are @code{strlen} or @code{memcmp}.
+Interesting non-pure functions are functions with infinite loops or those
+depending on volatile memory or other system resource, that may change between
+two consecutive calls (such as @code{feof} in a multithreading environment).
+
+The attribute @code{pure} is not implemented in GCC versions earlier
+than 2.96.
+@cindex @code{const} function attribute
+@item const
+Many functions do not examine any values except their arguments, and
+have no effects except the return value.  Basically this is just slightly
+more strict class than the @code{pure} attribute above, since function is not
+allowed to read global memory.
+
+@cindex pointer arguments
+Note that a function that has pointer arguments and examines the data
+pointed to must @emph{not} be declared @code{const}.  Likewise, a
+function that calls a non-@code{const} function usually must not be
+@code{const}.  It does not make sense for a @code{const} function to
+return @code{void}.
+
+The attribute @code{const} is not implemented in GCC versions earlier
+than 2.5.  An alternative way to declare that a function has no side
+effects, which works in the current version and in some older versions,
+is as follows:
+
+@smallexample
+typedef int intfn ();
+
+extern const intfn square;
+@end smallexample
+
+This approach does not work in GNU C++ from 2.6.0 on, since the language
+specifies that the @samp{const} must be attached to the return value.
+
+
+@item format (@var{archetype}, @var{string-index}, @var{first-to-check})
+@cindex @code{format} function attribute
+@opindex Wformat
+The @code{format} attribute specifies that a function takes @code{printf},
+@code{scanf}, @code{strftime} or @code{strfmon} style arguments which
+should be type-checked against a format string.  For example, the
+declaration:
+
+@smallexample
+extern int
+my_printf (void *my_object, const char *my_format, ...)
+      __attribute__ ((format (printf, 2, 3)));
+@end smallexample
+
+@noindent
+causes the compiler to check the arguments in calls to @code{my_printf}
+for consistency with the @code{printf} style format string argument
+@code{my_format}.
+
+The parameter @var{archetype} determines how the format string is
+interpreted, and should be @code{printf}, @code{scanf}, @code{strftime}
+or @code{strfmon}.  (You can also use @code{__printf__},
+@code{__scanf__}, @code{__strftime__} or @code{__strfmon__}.)  The
+parameter @var{string-index} specifies which argument is the format
+string argument (starting from 1), while @var{first-to-check} is the
+number of the first argument to check against the format string.  For
+functions where the arguments are not available to be checked (such as
+@code{vprintf}), specify the third parameter as zero.  In this case the
+compiler only checks the format string for consistency.  For
+@code{strftime} formats, the third parameter is required to be zero.
+
+In the example above, the format string (@code{my_format}) is the second
+argument of the function @code{my_print}, and the arguments to check
+start with the third argument, so the correct parameters for the format
+attribute are 2 and 3.
+
+@opindex ffreestanding
+The @code{format} attribute allows you to identify your own functions
+which take format strings as arguments, so that GCC can check the
+calls to these functions for errors.  The compiler always (unless
+@option{-ffreestanding} is used) checks formats
+for the standard library functions @code{printf}, @code{fprintf},
+@code{sprintf}, @code{scanf}, @code{fscanf}, @code{sscanf}, @code{strftime},
+@code{vprintf}, @code{vfprintf} and @code{vsprintf} whenever such
+warnings are requested (using @option{-Wformat}), so there is no need to
+modify the header file @file{stdio.h}.  In C99 mode, the functions
+@code{snprintf}, @code{vsnprintf}, @code{vscanf}, @code{vfscanf} and
+@code{vsscanf} are also checked.  Except in strictly conforming C
+standard modes, the X/Open function @code{strfmon} is also checked as
+are @code{printf_unlocked} and @code{fprintf_unlocked}.
+@xref{C Dialect Options,,Options Controlling C Dialect}.
+
+@item format_arg (@var{string-index})
+@cindex @code{format_arg} function attribute
+@opindex Wformat-nonliteral
+The @code{format_arg} attribute specifies that a function takes a format
+string for a @code{printf}, @code{scanf}, @code{strftime} or
+@code{strfmon} style function and modifies it (for example, to translate
+it into another language), so the result can be passed to a
+@code{printf}, @code{scanf}, @code{strftime} or @code{strfmon} style
+function (with the remaining arguments to the format function the same
+as they would have been for the unmodified string).  For example, the
+declaration:
+
+@smallexample
+extern char *
+my_dgettext (char *my_domain, const char *my_format)
+      __attribute__ ((format_arg (2)));
+@end smallexample
+
+@noindent
+causes the compiler to check the arguments in calls to a @code{printf},
+@code{scanf}, @code{strftime} or @code{strfmon} type function, whose
+format string argument is a call to the @code{my_dgettext} function, for
+consistency with the format string argument @code{my_format}.  If the
+@code{format_arg} attribute had not been specified, all the compiler
+could tell in such calls to format functions would be that the format
+string argument is not constant; this would generate a warning when
+@option{-Wformat-nonliteral} is used, but the calls could not be checked
+without the attribute.
+
+The parameter @var{string-index} specifies which argument is the format
+string argument (starting from 1).
+
+The @code{format-arg} attribute allows you to identify your own
+functions which modify format strings, so that GCC can check the
+calls to @code{printf}, @code{scanf}, @code{strftime} or @code{strfmon}
+type function whose operands are a call to one of your own function.
+The compiler always treats @code{gettext}, @code{dgettext}, and
+@code{dcgettext} in this manner except when strict ISO C support is
+requested by @option{-ansi} or an appropriate @option{-std} option, or
+@option{-ffreestanding} is used.  @xref{C Dialect Options,,Options
+Controlling C Dialect}.
+
+@item no_instrument_function
+@cindex @code{no_instrument_function} function attribute
+@opindex finstrument-functions
+If @option{-finstrument-functions} is given, profiling function calls will
+be generated at entry and exit of most user-compiled functions.
+Functions with this attribute will not be so instrumented.
+
+@item section ("@var{section-name}")
+@cindex @code{section} function attribute
+Normally, the compiler places the code it generates in the @code{text} section.
+Sometimes, however, you need additional sections, or you need certain
+particular functions to appear in special sections.  The @code{section}
+attribute specifies that a function lives in a particular section.
+For example, the declaration:
+
+@smallexample
+extern void foobar (void) __attribute__ ((section ("bar")));
+@end smallexample
+
+@noindent
+puts the function @code{foobar} in the @code{bar} section.
+
+Some file formats do not support arbitrary sections so the @code{section}
+attribute is not available on all platforms.
+If you need to map the entire contents of a module to a particular
+section, consider using the facilities of the linker instead.
+
+@item constructor
+@itemx destructor
+@cindex @code{constructor} function attribute
+@cindex @code{destructor} function attribute
+The @code{constructor} attribute causes the function to be called
+automatically before execution enters @code{main ()}.  Similarly, the
+@code{destructor} attribute causes the function to be called
+automatically after @code{main ()} has completed or @code{exit ()} has
+been called.  Functions with these attributes are useful for
+initializing data that will be used implicitly during the execution of
+the program.
+
+These attributes are not currently implemented for Objective-C@.
+
+@cindex @code{unused} attribute.
+@item unused
+This attribute, attached to a function, means that the function is meant
+to be possibly unused.  GCC will not produce a warning for this
+function.  GNU C++ does not currently support this attribute as
+definitions without parameters are valid in C++.
+
+@cindex @code{used} attribute.
+@item used
+This attribute, attached to a function, means that code must be emitted
+for the function even if it appears that the function is not referenced.
+This is useful, for example, when the function is referenced only in
+inline assembly.
+
+@cindex @code{deprecated} attribute.
+@item deprecated
+The @code{deprecated} attribute results in a warning if the function
+is used anywhere in the source file.  This is useful when identifying
+functions that are expected to be removed in a future version of a
+program.  The warning also includes the location of the declaration
+of the deprecated function, to enable users to easily find further
+information about why the function is deprecated, or what they should
+do instead.  Note that the warnings only occurs for uses:
+
+@smallexample
+int old_fn () __attribute__ ((deprecated));
+int old_fn ();
+int (*fn_ptr)() = old_fn;
+@end smallexample
+
+results in a warning on line 3 but not line 2.
+
+The @code{deprecated} attribute can also be used for variables and
+types (@pxref{Variable Attributes}, @pxref{Type Attributes}.)
+
+@item weak
+@cindex @code{weak} attribute
+The @code{weak} attribute causes the declaration to be emitted as a weak
+symbol rather than a global.  This is primarily useful in defining
+library functions which can be overridden in user code, though it can
+also be used with non-function declarations.  Weak symbols are supported
+for ELF targets, and also for a.out targets when using the GNU assembler
+and linker.
+
+@item malloc
+@cindex @code{malloc} attribute
+The @code{malloc} attribute is used to tell the compiler that a function
+may be treated as if it were the malloc function.  The compiler assumes
+that calls to malloc result in a pointers that cannot alias anything.
+This will often improve optimization.
+
+@item alias ("@var{target}")
+@cindex @code{alias} attribute
+The @code{alias} attribute causes the declaration to be emitted as an
+alias for another symbol, which must be specified.  For instance,
+
+@smallexample
+void __f () @{ /* do something */; @}
+void f () __attribute__ ((weak, alias ("__f")));
+@end smallexample
+
+declares @samp{f} to be a weak alias for @samp{__f}.  In C++, the
+mangled name for the target must be used.
+
+Not all target machines support this attribute.
+
+@item regparm (@var{number})
+@cindex functions that are passed arguments in registers on the 386
+On the Intel 386, the @code{regparm} attribute causes the compiler to
+pass up to @var{number} integer arguments in registers EAX,
+EDX, and ECX instead of on the stack.  Functions that take a
+variable number of arguments will continue to be passed all of their
+arguments on the stack.
+
+@item stdcall
+@cindex functions that pop the argument stack on the 386
+On the Intel 386, the @code{stdcall} attribute causes the compiler to
+assume that the called function will pop off the stack space used to
+pass arguments, unless it takes a variable number of arguments.
+
+The PowerPC compiler for Windows NT currently ignores the @code{stdcall}
+attribute.
+
+@item cdecl
+@cindex functions that do pop the argument stack on the 386
+@opindex mrtd
+On the Intel 386, the @code{cdecl} attribute causes the compiler to
+assume that the calling function will pop off the stack space used to
+pass arguments.  This is
+useful to override the effects of the @option{-mrtd} switch.
+
+The PowerPC compiler for Windows NT currently ignores the @code{cdecl}
+attribute.
+
+@item longcall
+@cindex functions called via pointer on the RS/6000 and PowerPC
+On the RS/6000 and PowerPC, the @code{longcall} attribute causes the
+compiler to always call the function via a pointer, so that functions
+which reside further than 64 megabytes (67,108,864 bytes) from the
+current location can be called.
+
+@item long_call/short_call
+@cindex indirect calls on ARM
+This attribute allows to specify how to call a particular function on
+ARM@.  Both attributes override the @option{-mlong-calls} (@pxref{ARM Options})
+command line switch and @code{#pragma long_calls} settings.  The
+@code{long_call} attribute causes the compiler to always call the
+function by first loading its address into a register and then using the
+contents of that register.   The @code{short_call} attribute always places
+the offset to the function from the call site into the @samp{BL}
+instruction directly.
+
+@item dllimport
+@cindex functions which are imported from a dll on PowerPC Windows NT
+On the PowerPC running Windows NT, the @code{dllimport} attribute causes
+the compiler to call the function via a global pointer to the function
+pointer that is set up by the Windows NT dll library.  The pointer name
+is formed by combining @code{__imp_} and the function name.
+
+@item dllexport
+@cindex functions which are exported from a dll on PowerPC Windows NT
+On the PowerPC running Windows NT, the @code{dllexport} attribute causes
+the compiler to provide a global pointer to the function pointer, so
+that it can be called with the @code{dllimport} attribute.  The pointer
+name is formed by combining @code{__imp_} and the function name.
+
+@item exception (@var{except-func} [, @var{except-arg}])
+@cindex functions which specify exception handling on PowerPC Windows NT
+On the PowerPC running Windows NT, the @code{exception} attribute causes
+the compiler to modify the structured exception table entry it emits for
+the declared function.  The string or identifier @var{except-func} is
+placed in the third entry of the structured exception table.  It
+represents a function, which is called by the exception handling
+mechanism if an exception occurs.  If it was specified, the string or
+identifier @var{except-arg} is placed in the fourth entry of the
+structured exception table.
+
+@item function_vector
+@cindex calling functions through the function vector on the H8/300 processors
+Use this attribute on the H8/300 and H8/300H to indicate that the specified
+function should be called through the function vector.  Calling a
+function through the function vector will reduce code size, however;
+the function vector has a limited size (maximum 128 entries on the H8/300
+and 64 entries on the H8/300H) and shares space with the interrupt vector.
+
+You must use GAS and GLD from GNU binutils version 2.7 or later for
+this attribute to work correctly.
+
+@item interrupt
+@cindex interrupt handler functions
+Use this attribute on the ARM, AVR, M32R/D and Xstormy16 ports to indicate
+that the specified function is an interrupt handler.  The compiler will
+generate function entry and exit sequences suitable for use in an
+interrupt handler when this attribute is present.
+
+Note, interrupt handlers for the H8/300, H8/300H and SH processors can
+be specified via the @code{interrupt_handler} attribute.
+
+Note, on the AVR interrupts will be enabled inside the function.
+
+Note, for the ARM you can specify the kind of interrupt to be handled by
+adding an optional parameter to the interrupt attribute like this:
+
+@smallexample
+void f () __attribute__ ((interrupt ("IRQ")));
+@end smallexample
+
+Permissible values for this parameter are: IRQ, FIQ, SWI, ABORT and UNDEF@.
+
+@item interrupt_handler
+@cindex interrupt handler functions on the H8/300 and SH processors
+Use this attribute on the H8/300, H8/300H and SH to indicate that the
+specified function is an interrupt handler.  The compiler will generate
+function entry and exit sequences suitable for use in an interrupt
+handler when this attribute is present.
+
+@item sp_switch
+Use this attribute on the SH to indicate an @code{interrupt_handler}
+function should switch to an alternate stack.  It expects a string
+argument that names a global variable holding the address of the
+alternate stack.
+
+@smallexample
+void *alt_stack;
+void f () __attribute__ ((interrupt_handler,
+                          sp_switch ("alt_stack")));
+@end smallexample
+
+@item trap_exit
+Use this attribute on the SH for an @code{interrupt_handle} to return using
+@code{trapa} instead of @code{rte}.  This attribute expects an integer
+argument specifying the trap number to be used.
+
+@item eightbit_data
+@cindex eight bit data on the H8/300 and H8/300H
+Use this attribute on the H8/300 and H8/300H to indicate that the specified
+variable should be placed into the eight bit data section.
+The compiler will generate more efficient code for certain operations
+on data in the eight bit data area.  Note the eight bit data area is limited to
+256 bytes of data.
+
+You must use GAS and GLD from GNU binutils version 2.7 or later for
+this attribute to work correctly.
+
+@item tiny_data
+@cindex tiny data section on the H8/300H
+Use this attribute on the H8/300H to indicate that the specified
+variable should be placed into the tiny data section.
+The compiler will generate more efficient code for loads and stores
+on data in the tiny data section.  Note the tiny data area is limited to
+slightly under 32kbytes of data.
+
+@item signal
+@cindex signal handler functions on the AVR processors
+Use this attribute on the AVR to indicate that the specified
+function is an signal handler.  The compiler will generate function
+entry and exit sequences suitable for use in an signal handler when this
+attribute is present.  Interrupts will be disabled inside function.
+
+@item naked
+@cindex function without a prologue/epilogue code
+Use this attribute on the ARM or AVR ports to indicate that the specified
+function do not need prologue/epilogue sequences generated by the
+compiler.  It is up to the programmer to provide these sequences.
+
+@item model (@var{model-name})
+@cindex function addressability on the M32R/D
+Use this attribute on the M32R/D to set the addressability of an object,
+and the code generated for a function.
+The identifier @var{model-name} is one of @code{small}, @code{medium},
+or @code{large}, representing each of the code models.
+
+Small model objects live in the lower 16MB of memory (so that their
+addresses can be loaded with the @code{ld24} instruction), and are
+callable with the @code{bl} instruction.
+
+Medium model objects may live anywhere in the 32-bit address space (the
+compiler will generate @code{seth/add3} instructions to load their addresses),
+and are callable with the @code{bl} instruction.
+
+Large model objects may live anywhere in the 32-bit address space (the
+compiler will generate @code{seth/add3} instructions to load their addresses),
+and may not be reachable with the @code{bl} instruction (the compiler will
+generate the much slower @code{seth/add3/jl} instruction sequence).
+
+@end table
+
+You can specify multiple attributes in a declaration by separating them
+by commas within the double parentheses or by immediately following an
+attribute declaration with another attribute declaration.
+
+@cindex @code{#pragma}, reason for not using
+@cindex pragma, reason for not using
+Some people object to the @code{__attribute__} feature, suggesting that
+ISO C's @code{#pragma} should be used instead.  At the time
+@code{__attribute__} was designed, there were two reasons for not doing
+this.
+
+@enumerate
+@item
+It is impossible to generate @code{#pragma} commands from a macro.
+
+@item
+There is no telling what the same @code{#pragma} might mean in another
+compiler.
+@end enumerate
+
+These two reasons applied to almost any application that might have been
+proposed for @code{#pragma}.  It was basically a mistake to use
+@code{#pragma} for @emph{anything}.
+
+The ISO C99 standard includes @code{_Pragma}, which now allows pragmas
+to be generated from macros.  In addition, a @code{#pragma GCC}
+namespace is now in use for GCC-specific pragmas.  However, it has been
+found convenient to use @code{__attribute__} to achieve a natural
+attachment of attributes to their corresponding declarations, whereas
+@code{#pragma GCC} is of use for constructs that do not naturally form
+part of the grammar.  @xref{Other Directives,,Miscellaneous
+Preprocessing Directives, cpp, The C Preprocessor}.
+
+@node Attribute Syntax
+@section Attribute Syntax
+@cindex attribute syntax
+
+This section describes the syntax with which @code{__attribute__} may be
+used, and the constructs to which attribute specifiers bind, for the C
+language.  Some details may vary for C++ and Objective-C@.  Because of
+infelicities in the grammar for attributes, some forms described here
+may not be successfully parsed in all cases.
+
+There are some problems with the semantics of attributes in C++.  For
+example, there are no manglings for attributes, although they may affect
+code generation, so problems may arise when attributed types are used in
+conjunction with templates or overloading.  Similarly, @code{typeid}
+does not distinguish between types with different attributes.  Support
+for attributes in C++ may be restricted in future to attributes on
+declarations only, but not on nested declarators.
+
+@xref{Function Attributes}, for details of the semantics of attributes
+applying to functions.  @xref{Variable Attributes}, for details of the
+semantics of attributes applying to variables.  @xref{Type Attributes},
+for details of the semantics of attributes applying to structure, union
+and enumerated types.
+
+An @dfn{attribute specifier} is of the form
+@code{__attribute__ ((@var{attribute-list}))}.  An @dfn{attribute list}
+is a possibly empty comma-separated sequence of @dfn{attributes}, where
+each attribute is one of the following:
+
+@itemize @bullet
+@item
+Empty.  Empty attributes are ignored.
+
+@item
+A word (which may be an identifier such as @code{unused}, or a reserved
+word such as @code{const}).
+
+@item
+A word, followed by, in parentheses, parameters for the attribute.
+These parameters take one of the following forms:
+
+@itemize @bullet
+@item
+An identifier.  For example, @code{mode} attributes use this form.
+
+@item
+An identifier followed by a comma and a non-empty comma-separated list
+of expressions.  For example, @code{format} attributes use this form.
+
+@item
+A possibly empty comma-separated list of expressions.  For example,
+@code{format_arg} attributes use this form with the list being a single
+integer constant expression, and @code{alias} attributes use this form
+with the list being a single string constant.
+@end itemize
+@end itemize
+
+An @dfn{attribute specifier list} is a sequence of one or more attribute
+specifiers, not separated by any other tokens.
+
+An attribute specifier list may appear after the colon following a
+label, other than a @code{case} or @code{default} label.  The only
+attribute it makes sense to use after a label is @code{unused}.  This
+feature is intended for code generated by programs which contains labels
+that may be unused but which is compiled with @option{-Wall}.  It would
+not normally be appropriate to use in it human-written code, though it
+could be useful in cases where the code that jumps to the label is
+contained within an @code{#ifdef} conditional.
+
+An attribute specifier list may appear as part of a @code{struct},
+@code{union} or @code{enum} specifier.  It may go either immediately
+after the @code{struct}, @code{union} or @code{enum} keyword, or after
+the closing brace.  It is ignored if the content of the structure, union
+or enumerated type is not defined in the specifier in which the
+attribute specifier list is used---that is, in usages such as
+@code{struct __attribute__((foo)) bar} with no following opening brace.
+Where attribute specifiers follow the closing brace, they are considered
+to relate to the structure, union or enumerated type defined, not to any
+enclosing declaration the type specifier appears in, and the type
+defined is not complete until after the attribute specifiers.
+@c Otherwise, there would be the following problems: a shift/reduce
+@c conflict between attributes binding the struct/union/enum and
+@c binding to the list of specifiers/qualifiers; and "aligned"
+@c attributes could use sizeof for the structure, but the size could be
+@c changed later by "packed" attributes.
+
+Otherwise, an attribute specifier appears as part of a declaration,
+counting declarations of unnamed parameters and type names, and relates
+to that declaration (which may be nested in another declaration, for
+example in the case of a parameter declaration), or to a particular declarator
+within a declaration.  Where an
+attribute specifier is applied to a parameter declared as a function or
+an array, it should apply to the function or array rather than the
+pointer to which the parameter is implicitly converted, but this is not
+yet correctly implemented.
+
+Any list of specifiers and qualifiers at the start of a declaration may
+contain attribute specifiers, whether or not such a list may in that
+context contain storage class specifiers.  (Some attributes, however,
+are essentially in the nature of storage class specifiers, and only make
+sense where storage class specifiers may be used; for example,
+@code{section}.)  There is one necessary limitation to this syntax: the
+first old-style parameter declaration in a function definition cannot
+begin with an attribute specifier, because such an attribute applies to
+the function instead by syntax described below (which, however, is not
+yet implemented in this case).  In some other cases, attribute
+specifiers are permitted by this grammar but not yet supported by the
+compiler.  All attribute specifiers in this place relate to the
+declaration as a whole.  In the obsolescent usage where a type of
+@code{int} is implied by the absence of type specifiers, such a list of
+specifiers and qualifiers may be an attribute specifier list with no
+other specifiers or qualifiers.
+
+An attribute specifier list may appear immediately before a declarator
+(other than the first) in a comma-separated list of declarators in a
+declaration of more than one identifier using a single list of
+specifiers and qualifiers.  Such attribute specifiers apply
+only to the identifier before whose declarator they appear.  For
+example, in
+
+@smallexample
+__attribute__((noreturn)) void d0 (void),
+    __attribute__((format(printf, 1, 2))) d1 (const char *, ...),
+     d2 (void)
+@end smallexample
+
+@noindent
+the @code{noreturn} attribute applies to all the functions
+declared; the @code{format} attribute only applies to @code{d1}.
+
+An attribute specifier list may appear immediately before the comma,
+@code{=} or semicolon terminating the declaration of an identifier other
+than a function definition.  At present, such attribute specifiers apply
+to the declared object or function, but in future they may attach to the
+outermost adjacent declarator.  In simple cases there is no difference,
+but, for example, in 
+
+@smallexample
+void (****f)(void) __attribute__((noreturn));
+@end smallexample
+
+@noindent
+at present the @code{noreturn} attribute applies to @code{f}, which
+causes a warning since @code{f} is not a function, but in future it may
+apply to the function @code{****f}.  The precise semantics of what
+attributes in such cases will apply to are not yet specified.  Where an
+assembler name for an object or function is specified (@pxref{Asm
+Labels}), at present the attribute must follow the @code{asm}
+specification; in future, attributes before the @code{asm} specification
+may apply to the adjacent declarator, and those after it to the declared
+object or function.
+
+An attribute specifier list may, in future, be permitted to appear after
+the declarator in a function definition (before any old-style parameter
+declarations or the function body).
+
+Attribute specifiers may be mixed with type qualifiers appearing inside
+the @code{[]} of a parameter array declarator, in the C99 construct by
+which such qualifiers are applied to the pointer to which the array is
+implicitly converted.  Such attribute specifiers apply to the pointer,
+not to the array, but at present this is not implemented and they are
+ignored.
+
+An attribute specifier list may appear at the start of a nested
+declarator.  At present, there are some limitations in this usage: the
+attributes correctly apply to the declarator, but for most individual
+attributes the semantics this implies are not implemented.
+When attribute specifiers follow the @code{*} of a pointer
+declarator, they may be mixed with any type qualifiers present.
+The following describes the formal semantics of this syntax.  It will make the
+most sense if you are familiar with the formal specification of
+declarators in the ISO C standard.
+
+Consider (as in C99 subclause 6.7.5 paragraph 4) a declaration @code{T
+D1}, where @code{T} contains declaration specifiers that specify a type
+@var{Type} (such as @code{int}) and @code{D1} is a declarator that
+contains an identifier @var{ident}.  The type specified for @var{ident}
+for derived declarators whose type does not include an attribute
+specifier is as in the ISO C standard.
+
+If @code{D1} has the form @code{( @var{attribute-specifier-list} D )},
+and the declaration @code{T D} specifies the type
+``@var{derived-declarator-type-list} @var{Type}'' for @var{ident}, then
+@code{T D1} specifies the type ``@var{derived-declarator-type-list}
+@var{attribute-specifier-list} @var{Type}'' for @var{ident}.
+
+If @code{D1} has the form @code{*
+@var{type-qualifier-and-attribute-specifier-list} D}, and the
+declaration @code{T D} specifies the type
+``@var{derived-declarator-type-list} @var{Type}'' for @var{ident}, then
+@code{T D1} specifies the type ``@var{derived-declarator-type-list}
+@var{type-qualifier-and-attribute-specifier-list} @var{Type}'' for
+@var{ident}.
+
+For example, 
+
+@smallexample
+void (__attribute__((noreturn)) ****f) (void);
+@end smallexample
+
+@noindent
+specifies the type ``pointer to pointer to pointer to pointer to
+non-returning function returning @code{void}''.  As another example,
+
+@smallexample
+char *__attribute__((aligned(8))) *f;
+@end smallexample
+
+@noindent
+specifies the type ``pointer to 8-byte-aligned pointer to @code{char}''.
+Note again that this does not work with most attributes; for example,
+the usage of @samp{aligned} and @samp{noreturn} attributes given above
+is not yet supported.
+
+For compatibility with existing code written for compiler versions that
+did not implement attributes on nested declarators, some laxity is
+allowed in the placing of attributes.  If an attribute that only applies
+to types is applied to a declaration, it will be treated as applying to
+the type of that declaration.  If an attribute that only applies to
+declarations is applied to the type of a declaration, it will be treated
+as applying to that declaration; and, for compatibility with code
+placing the attributes immediately before the identifier declared, such
+an attribute applied to a function return type will be treated as
+applying to the function type, and such an attribute applied to an array
+element type will be treated as applying to the array type.  If an
+attribute that only applies to function types is applied to a
+pointer-to-function type, it will be treated as applying to the pointer
+target type; if such an attribute is applied to a function return type
+that is not a pointer-to-function type, it will be treated as applying
+to the function type.
+
+@node Function Prototypes
+@section Prototypes and Old-Style Function Definitions
+@cindex function prototype declarations
+@cindex old-style function definitions
+@cindex promotion of formal parameters
+
+GNU C extends ISO C to allow a function prototype to override a later
+old-style non-prototype definition.  Consider the following example:
+
+@example
+/* @r{Use prototypes unless the compiler is old-fashioned.}  */
+#ifdef __STDC__
+#define P(x) x
+#else
+#define P(x) ()
+#endif
+
+/* @r{Prototype function declaration.}  */
+int isroot P((uid_t));
+
+/* @r{Old-style function definition.}  */
+int
+isroot (x)   /* ??? lossage here ??? */
+     uid_t x;
+@{
+  return x == 0;
+@}
+@end example
+
+Suppose the type @code{uid_t} happens to be @code{short}.  ISO C does
+not allow this example, because subword arguments in old-style
+non-prototype definitions are promoted.  Therefore in this example the
+function definition's argument is really an @code{int}, which does not
+match the prototype argument type of @code{short}.
+
+This restriction of ISO C makes it hard to write code that is portable
+to traditional C compilers, because the programmer does not know
+whether the @code{uid_t} type is @code{short}, @code{int}, or
+@code{long}.  Therefore, in cases like these GNU C allows a prototype
+to override a later old-style definition.  More precisely, in GNU C, a
+function prototype argument type overrides the argument type specified
+by a later old-style definition if the former type is the same as the
+latter type before promotion.  Thus in GNU C the above example is
+equivalent to the following:
+
+@example
+int isroot (uid_t);
+
+int
+isroot (uid_t x)
+@{
+  return x == 0;
+@}
+@end example
+
+@noindent
+GNU C++ does not support old-style function definitions, so this
+extension is irrelevant.
+
+@node C++ Comments
+@section C++ Style Comments
+@cindex //
+@cindex C++ comments
+@cindex comments, C++ style
+
+In GNU C, you may use C++ style comments, which start with @samp{//} and
+continue until the end of the line.  Many other C implementations allow
+such comments, and they are likely to be in a future C standard.
+However, C++ style comments are not recognized if you specify
+@w{@option{-ansi}}, a @option{-std} option specifying a version of ISO C
+before C99, or @w{@option{-traditional}}, since they are incompatible
+with traditional constructs like @code{dividend//*comment*/divisor}.
+
+@node Dollar Signs
+@section Dollar Signs in Identifier Names
+@cindex $
+@cindex dollar signs in identifier names
+@cindex identifier names, dollar signs in
+
+In GNU C, you may normally use dollar signs in identifier names.
+This is because many traditional C implementations allow such identifiers.
+However, dollar signs in identifiers are not supported on a few target
+machines, typically because the target assembler does not allow them.
+
+@node Character Escapes
+@section The Character @key{ESC} in Constants
+
+You can use the sequence @samp{\e} in a string or character constant to
+stand for the ASCII character @key{ESC}.
+
+@node Alignment
+@section Inquiring on Alignment of Types or Variables
+@cindex alignment
+@cindex type alignment
+@cindex variable alignment
+
+The keyword @code{__alignof__} allows you to inquire about how an object
+is aligned, or the minimum alignment usually required by a type.  Its
+syntax is just like @code{sizeof}.
+
+For example, if the target machine requires a @code{double} value to be
+aligned on an 8-byte boundary, then @code{__alignof__ (double)} is 8.
+This is true on many RISC machines.  On more traditional machine
+designs, @code{__alignof__ (double)} is 4 or even 2.
+
+Some machines never actually require alignment; they allow reference to any
+data type even at an odd addresses.  For these machines, @code{__alignof__}
+reports the @emph{recommended} alignment of a type.
+
+If the operand of @code{__alignof__} is an lvalue rather than a type,
+its value is the required alignment for its type, taking into account
+any minimum alignment specified with GCC's @code{__attribute__}
+extension (@pxref{Variable Attributes}).  For example, after this
+declaration:
+
+@example
+struct foo @{ int x; char y; @} foo1;
+@end example
+
+@noindent
+the value of @code{__alignof__ (foo1.y)} is 1, even though its actual
+alignment is probably 2 or 4, the same as @code{__alignof__ (int)}.
+
+It is an error to ask for the alignment of an incomplete type.
+
+@node Variable Attributes
+@section Specifying Attributes of Variables
+@cindex attribute of variables
+@cindex variable attributes
+
+The keyword @code{__attribute__} allows you to specify special
+attributes of variables or structure fields.  This keyword is followed
+by an attribute specification inside double parentheses.  Ten
+attributes are currently defined for variables: @code{aligned},
+@code{mode}, @code{nocommon}, @code{packed}, @code{section},
+@code{transparent_union}, @code{unused}, @code{deprecated},
+@code{vector_size}, and @code{weak}.  Some other attributes are defined
+for variables on particular target systems.  Other attributes are
+available for functions (@pxref{Function Attributes}) and for types
+(@pxref{Type Attributes}).  Other front ends might define more
+attributes (@pxref{C++ Extensions,,Extensions to the C++ Language}).
+
+You may also specify attributes with @samp{__} preceding and following
+each keyword.  This allows you to use them in header files without
+being concerned about a possible macro of the same name.  For example,
+you may use @code{__aligned__} instead of @code{aligned}.
+
+@xref{Attribute Syntax}, for details of the exact syntax for using
+attributes.
+
+@table @code
+@cindex @code{aligned} attribute
+@item aligned (@var{alignment})
+This attribute specifies a minimum alignment for the variable or
+structure field, measured in bytes.  For example, the declaration:
+
+@smallexample
+int x __attribute__ ((aligned (16))) = 0;
+@end smallexample
+
+@noindent
+causes the compiler to allocate the global variable @code{x} on a
+16-byte boundary.  On a 68040, this could be used in conjunction with
+an @code{asm} expression to access the @code{move16} instruction which
+requires 16-byte aligned operands.
+
+You can also specify the alignment of structure fields.  For example, to
+create a double-word aligned @code{int} pair, you could write:
+
+@smallexample
+struct foo @{ int x[2] __attribute__ ((aligned (8))); @};
+@end smallexample
+
+@noindent
+This is an alternative to creating a union with a @code{double} member
+that forces the union to be double-word aligned.
+
+It is not possible to specify the alignment of functions; the alignment
+of functions is determined by the machine's requirements and cannot be
+changed.  You cannot specify alignment for a typedef name because such a
+name is just an alias, not a distinct type.
+
+As in the preceding examples, you can explicitly specify the alignment
+(in bytes) that you wish the compiler to use for a given variable or
+structure field.  Alternatively, you can leave out the alignment factor
+and just ask the compiler to align a variable or field to the maximum
+useful alignment for the target machine you are compiling for.  For
+example, you could write:
+
+@smallexample
+short array[3] __attribute__ ((aligned));
+@end smallexample
+
+Whenever you leave out the alignment factor in an @code{aligned} attribute
+specification, the compiler automatically sets the alignment for the declared
+variable or field to the largest alignment which is ever used for any data
+type on the target machine you are compiling for.  Doing this can often make
+copy operations more efficient, because the compiler can use whatever
+instructions copy the biggest chunks of memory when performing copies to
+or from the variables or fields that you have aligned this way.
+
+The @code{aligned} attribute can only increase the alignment; but you
+can decrease it by specifying @code{packed} as well.  See below.
+
+Note that the effectiveness of @code{aligned} attributes may be limited
+by inherent limitations in your linker.  On many systems, the linker is
+only able to arrange for variables to be aligned up to a certain maximum
+alignment.  (For some linkers, the maximum supported alignment may
+be very very small.)  If your linker is only able to align variables
+up to a maximum of 8 byte alignment, then specifying @code{aligned(16)}
+in an @code{__attribute__} will still only provide you with 8 byte
+alignment.  See your linker documentation for further information.
+
+@item mode (@var{mode})
+@cindex @code{mode} attribute
+This attribute specifies the data type for the declaration---whichever
+type corresponds to the mode @var{mode}.  This in effect lets you
+request an integer or floating point type according to its width.
+
+You may also specify a mode of @samp{byte} or @samp{__byte__} to
+indicate the mode corresponding to a one-byte integer, @samp{word} or
+@samp{__word__} for the mode of a one-word integer, and @samp{pointer}
+or @samp{__pointer__} for the mode used to represent pointers.
+
+@item nocommon
+@cindex @code{nocommon} attribute
+@opindex fno-common
+This attribute specifies requests GCC not to place a variable
+``common'' but instead to allocate space for it directly.  If you
+specify the @option{-fno-common} flag, GCC will do this for all
+variables.
+
+Specifying the @code{nocommon} attribute for a variable provides an
+initialization of zeros.  A variable may only be initialized in one
+source file.
+
+@item packed
+@cindex @code{packed} attribute
+The @code{packed} attribute specifies that a variable or structure field
+should have the smallest possible alignment---one byte for a variable,
+and one bit for a field, unless you specify a larger value with the
+@code{aligned} attribute.
+
+Here is a structure in which the field @code{x} is packed, so that it
+immediately follows @code{a}:
+
+@example
+struct foo
+@{
+  char a;
+  int x[2] __attribute__ ((packed));
+@};
+@end example
+
+@item section ("@var{section-name}")
+@cindex @code{section} variable attribute
+Normally, the compiler places the objects it generates in sections like
+@code{data} and @code{bss}.  Sometimes, however, you need additional sections,
+or you need certain particular variables to appear in special sections,
+for example to map to special hardware.  The @code{section}
+attribute specifies that a variable (or function) lives in a particular
+section.  For example, this small program uses several specific section names:
+
+@smallexample
+struct duart a __attribute__ ((section ("DUART_A"))) = @{ 0 @};
+struct duart b __attribute__ ((section ("DUART_B"))) = @{ 0 @};
+char stack[10000] __attribute__ ((section ("STACK"))) = @{ 0 @};
+int init_data __attribute__ ((section ("INITDATA"))) = 0;
+
+main()
+@{
+  /* Initialize stack pointer */
+  init_sp (stack + sizeof (stack));
+
+  /* Initialize initialized data */
+  memcpy (&init_data, &data, &edata - &data);
+
+  /* Turn on the serial ports */
+  init_duart (&a);
+  init_duart (&b);
+@}
+@end smallexample
+
+@noindent
+Use the @code{section} attribute with an @emph{initialized} definition
+of a @emph{global} variable, as shown in the example.  GCC issues
+a warning and otherwise ignores the @code{section} attribute in
+uninitialized variable declarations.
+
+You may only use the @code{section} attribute with a fully initialized
+global definition because of the way linkers work.  The linker requires
+each object be defined once, with the exception that uninitialized
+variables tentatively go in the @code{common} (or @code{bss}) section
+and can be multiply ``defined''.  You can force a variable to be
+initialized with the @option{-fno-common} flag or the @code{nocommon}
+attribute.
+
+Some file formats do not support arbitrary sections so the @code{section}
+attribute is not available on all platforms.
+If you need to map the entire contents of a module to a particular
+section, consider using the facilities of the linker instead.
+
+@item shared
+@cindex @code{shared} variable attribute
+On Windows NT, in addition to putting variable definitions in a named
+section, the section can also be shared among all running copies of an
+executable or DLL@.  For example, this small program defines shared data
+by putting it in a named section @code{shared} and marking the section
+shareable:
+
+@smallexample
+int foo __attribute__((section ("shared"), shared)) = 0;
+
+int
+main()
+@{
+  /* Read and write foo.  All running
+     copies see the same value.  */
+  return 0;
+@}
+@end smallexample
+
+@noindent
+You may only use the @code{shared} attribute along with @code{section}
+attribute with a fully initialized global definition because of the way
+linkers work.  See @code{section} attribute for more information.
+
+The @code{shared} attribute is only available on Windows NT@.
+
+@item transparent_union
+This attribute, attached to a function parameter which is a union, means
+that the corresponding argument may have the type of any union member,
+but the argument is passed as if its type were that of the first union
+member.  For more details see @xref{Type Attributes}.  You can also use
+this attribute on a @code{typedef} for a union data type; then it
+applies to all function parameters with that type.
+
+@item unused
+This attribute, attached to a variable, means that the variable is meant
+to be possibly unused.  GCC will not produce a warning for this
+variable.
+
+@item deprecated
+The @code{deprecated} attribute results in a warning if the variable
+is used anywhere in the source file.  This is useful when identifying
+variables that are expected to be removed in a future version of a
+program.  The warning also includes the location of the declaration
+of the deprecated variable, to enable users to easily find further
+information about why the variable is deprecated, or what they should
+do instead.  Note that the warnings only occurs for uses:
+
+@smallexample
+extern int old_var __attribute__ ((deprecated));
+extern int old_var;
+int new_fn () @{ return old_var; @}
+@end smallexample
+
+results in a warning on line 3 but not line 2.
+
+The @code{deprecated} attribute can also be used for functions and
+types (@pxref{Function Attributes}, @pxref{Type Attributes}.)
+
+@item vector_size (@var{bytes})
+This attribute specifies the vector size for the variable, measured in
+bytes.  For example, the declaration:
+
+@smallexample
+int foo __attribute__ ((vector_size (16)));
+@end smallexample
+
+@noindent
+causes the compiler to set the mode for @code{foo}, to be 16 bytes,
+divided into @code{int} sized units.  Assuming a 32-bit int (a vector of
+4 units of 4 bytes), the corresponding mode of @code{foo} will be V4SI@.
+
+This attribute is only applicable to integral and float scalars,
+although arrays, pointers, and function return values are allowed in
+conjunction with this construct.
+
+Aggregates with this attribute are invalid, even if they are of the same
+size as a corresponding scalar.  For example, the declaration:
+
+@smallexample
+struct S @{ int a; @};
+struct S  __attribute__ ((vector_size (16))) foo;
+@end smallexample
+
+@noindent
+is invalid even if the size of the structure is the same as the size of
+the @code{int}.
+
+@item weak
+The @code{weak} attribute is described in @xref{Function Attributes}.
+
+@item model (@var{model-name})
+@cindex variable addressability on the M32R/D
+Use this attribute on the M32R/D to set the addressability of an object.
+The identifier @var{model-name} is one of @code{small}, @code{medium},
+or @code{large}, representing each of the code models.
+
+Small model objects live in the lower 16MB of memory (so that their
+addresses can be loaded with the @code{ld24} instruction).
+
+Medium and large model objects may live anywhere in the 32-bit address space
+(the compiler will generate @code{seth/add3} instructions to load their
+addresses).
+
+@end table
+
+To specify multiple attributes, separate them by commas within the
+double parentheses: for example, @samp{__attribute__ ((aligned (16),
+packed))}.
+
+@node Type Attributes
+@section Specifying Attributes of Types
+@cindex attribute of types
+@cindex type attributes
+
+The keyword @code{__attribute__} allows you to specify special
+attributes of @code{struct} and @code{union} types when you define such
+types.  This keyword is followed by an attribute specification inside
+double parentheses.  Five attributes are currently defined for types:
+@code{aligned}, @code{packed}, @code{transparent_union}, @code{unused},
+and @code{deprecated}.  Other attributes are defined for functions
+(@pxref{Function Attributes}) and for variables (@pxref{Variable Attributes}).
+
+You may also specify any one of these attributes with @samp{__}
+preceding and following its keyword.  This allows you to use these
+attributes in header files without being concerned about a possible
+macro of the same name.  For example, you may use @code{__aligned__}
+instead of @code{aligned}.
+
+You may specify the @code{aligned} and @code{transparent_union}
+attributes either in a @code{typedef} declaration or just past the
+closing curly brace of a complete enum, struct or union type
+@emph{definition} and the @code{packed} attribute only past the closing
+brace of a definition.
+
+You may also specify attributes between the enum, struct or union
+tag and the name of the type rather than after the closing brace.
+
+@xref{Attribute Syntax}, for details of the exact syntax for using
+attributes.
+
+@table @code
+@cindex @code{aligned} attribute
+@item aligned (@var{alignment})
+This attribute specifies a minimum alignment (in bytes) for variables
+of the specified type.  For example, the declarations:
+
+@smallexample
+struct S @{ short f[3]; @} __attribute__ ((aligned (8)));
+typedef int more_aligned_int __attribute__ ((aligned (8)));
+@end smallexample
+
+@noindent
+force the compiler to insure (as far as it can) that each variable whose
+type is @code{struct S} or @code{more_aligned_int} will be allocated and
+aligned @emph{at least} on a 8-byte boundary.  On a Sparc, having all
+variables of type @code{struct S} aligned to 8-byte boundaries allows
+the compiler to use the @code{ldd} and @code{std} (doubleword load and
+store) instructions when copying one variable of type @code{struct S} to
+another, thus improving run-time efficiency.
+
+Note that the alignment of any given @code{struct} or @code{union} type
+is required by the ISO C standard to be at least a perfect multiple of
+the lowest common multiple of the alignments of all of the members of
+the @code{struct} or @code{union} in question.  This means that you @emph{can}
+effectively adjust the alignment of a @code{struct} or @code{union}
+type by attaching an @code{aligned} attribute to any one of the members
+of such a type, but the notation illustrated in the example above is a
+more obvious, intuitive, and readable way to request the compiler to
+adjust the alignment of an entire @code{struct} or @code{union} type.
+
+As in the preceding example, you can explicitly specify the alignment
+(in bytes) that you wish the compiler to use for a given @code{struct}
+or @code{union} type.  Alternatively, you can leave out the alignment factor
+and just ask the compiler to align a type to the maximum
+useful alignment for the target machine you are compiling for.  For
+example, you could write:
+
+@smallexample
+struct S @{ short f[3]; @} __attribute__ ((aligned));
+@end smallexample
+
+Whenever you leave out the alignment factor in an @code{aligned}
+attribute specification, the compiler automatically sets the alignment
+for the type to the largest alignment which is ever used for any data
+type on the target machine you are compiling for.  Doing this can often
+make copy operations more efficient, because the compiler can use
+whatever instructions copy the biggest chunks of memory when performing
+copies to or from the variables which have types that you have aligned
+this way.
+
+In the example above, if the size of each @code{short} is 2 bytes, then
+the size of the entire @code{struct S} type is 6 bytes.  The smallest
+power of two which is greater than or equal to that is 8, so the
+compiler sets the alignment for the entire @code{struct S} type to 8
+bytes.
+
+Note that although you can ask the compiler to select a time-efficient
+alignment for a given type and then declare only individual stand-alone
+objects of that type, the compiler's ability to select a time-efficient
+alignment is primarily useful only when you plan to create arrays of
+variables having the relevant (efficiently aligned) type.  If you
+declare or use arrays of variables of an efficiently-aligned type, then
+it is likely that your program will also be doing pointer arithmetic (or
+subscripting, which amounts to the same thing) on pointers to the
+relevant type, and the code that the compiler generates for these
+pointer arithmetic operations will often be more efficient for
+efficiently-aligned types than for other types.
+
+The @code{aligned} attribute can only increase the alignment; but you
+can decrease it by specifying @code{packed} as well.  See below.
+
+Note that the effectiveness of @code{aligned} attributes may be limited
+by inherent limitations in your linker.  On many systems, the linker is
+only able to arrange for variables to be aligned up to a certain maximum
+alignment.  (For some linkers, the maximum supported alignment may
+be very very small.)  If your linker is only able to align variables
+up to a maximum of 8 byte alignment, then specifying @code{aligned(16)}
+in an @code{__attribute__} will still only provide you with 8 byte
+alignment.  See your linker documentation for further information.
+
+@item packed
+This attribute, attached to an @code{enum}, @code{struct}, or
+@code{union} type definition, specified that the minimum required memory
+be used to represent the type.
+
+@opindex fshort-enums
+Specifying this attribute for @code{struct} and @code{union} types is
+equivalent to specifying the @code{packed} attribute on each of the
+structure or union members.  Specifying the @option{-fshort-enums}
+flag on the line is equivalent to specifying the @code{packed}
+attribute on all @code{enum} definitions.
+
+You may only specify this attribute after a closing curly brace on an
+@code{enum} definition, not in a @code{typedef} declaration, unless that
+declaration also contains the definition of the @code{enum}.
+
+@item transparent_union
+This attribute, attached to a @code{union} type definition, indicates
+that any function parameter having that union type causes calls to that
+function to be treated in a special way.
+
+First, the argument corresponding to a transparent union type can be of
+any type in the union; no cast is required.  Also, if the union contains
+a pointer type, the corresponding argument can be a null pointer
+constant or a void pointer expression; and if the union contains a void
+pointer type, the corresponding argument can be any pointer expression.
+If the union member type is a pointer, qualifiers like @code{const} on
+the referenced type must be respected, just as with normal pointer
+conversions.
+
+Second, the argument is passed to the function using the calling
+conventions of first member of the transparent union, not the calling
+conventions of the union itself.  All members of the union must have the
+same machine representation; this is necessary for this argument passing
+to work properly.
+
+Transparent unions are designed for library functions that have multiple
+interfaces for compatibility reasons.  For example, suppose the
+@code{wait} function must accept either a value of type @code{int *} to
+comply with Posix, or a value of type @code{union wait *} to comply with
+the 4.1BSD interface.  If @code{wait}'s parameter were @code{void *},
+@code{wait} would accept both kinds of arguments, but it would also
+accept any other pointer type and this would make argument type checking
+less useful.  Instead, @code{<sys/wait.h>} might define the interface
+as follows:
+
+@smallexample
+typedef union
+  @{
+    int *__ip;
+    union wait *__up;
+  @} wait_status_ptr_t __attribute__ ((__transparent_union__));
+
+pid_t wait (wait_status_ptr_t);
+@end smallexample
+
+This interface allows either @code{int *} or @code{union wait *}
+arguments to be passed, using the @code{int *} calling convention.
+The program can call @code{wait} with arguments of either type:
+
+@example
+int w1 () @{ int w; return wait (&w); @}
+int w2 () @{ union wait w; return wait (&w); @}
+@end example
+
+With this interface, @code{wait}'s implementation might look like this:
+
+@example
+pid_t wait (wait_status_ptr_t p)
+@{
+  return waitpid (-1, p.__ip, 0);
+@}
+@end example
+
+@item unused
+When attached to a type (including a @code{union} or a @code{struct}),
+this attribute means that variables of that type are meant to appear
+possibly unused.  GCC will not produce a warning for any variables of
+that type, even if the variable appears to do nothing.  This is often
+the case with lock or thread classes, which are usually defined and then
+not referenced, but contain constructors and destructors that have
+nontrivial bookkeeping functions.
+
+@item deprecated
+The @code{deprecated} attribute results in a warning if the type
+is used anywhere in the source file.  This is useful when identifying
+types that are expected to be removed in a future version of a program.
+If possible, the warning also includes the location of the declaration
+of the deprecated type, to enable users to easily find further
+information about why the type is deprecated, or what they should do
+instead.  Note that the warnings only occur for uses and then only
+if the type is being applied to an identifier that itself is not being
+declared as deprecated.
+
+@smallexample
+typedef int T1 __attribute__ ((deprecated));
+T1 x;
+typedef T1 T2;
+T2 y;
+typedef T1 T3 __attribute__ ((deprecated));
+T3 z __attribute__ ((deprecated));
+@end smallexample
+
+results in a warning on line 2 and 3 but not lines 4, 5, or 6.  No
+warning is issued for line 4 because T2 is not explicitly
+deprecated.  Line 5 has no warning because T3 is explicitly
+deprecated.  Similarly for line 6.
+
+The @code{deprecated} attribute can also be used for functions and
+variables (@pxref{Function Attributes}, @pxref{Variable Attributes}.)
+
+@end table
+
+To specify multiple attributes, separate them by commas within the
+double parentheses: for example, @samp{__attribute__ ((aligned (16),
+packed))}.
+
+@node Inline
+@section An Inline Function is As Fast As a Macro
+@cindex inline functions
+@cindex integrating function code
+@cindex open coding
+@cindex macros, inline alternative
+
+By declaring a function @code{inline}, you can direct GCC to
+integrate that function's code into the code for its callers.  This
+makes execution faster by eliminating the function-call overhead; in
+addition, if any of the actual argument values are constant, their known
+values may permit simplifications at compile time so that not all of the
+inline function's code needs to be included.  The effect on code size is
+less predictable; object code may be larger or smaller with function
+inlining, depending on the particular case.  Inlining of functions is an
+optimization and it really ``works'' only in optimizing compilation.  If
+you don't use @option{-O}, no function is really inline.
+
+Inline functions are included in the ISO C99 standard, but there are
+currently substantial differences between what GCC implements and what
+the ISO C99 standard requires.
+
+To declare a function inline, use the @code{inline} keyword in its
+declaration, like this:
+
+@example
+inline int
+inc (int *a)
+@{
+  (*a)++;
+@}
+@end example
+
+(If you are writing a header file to be included in ISO C programs, write
+@code{__inline__} instead of @code{inline}.  @xref{Alternate Keywords}.)
+You can also make all ``simple enough'' functions inline with the option
+@option{-finline-functions}.
+
+@opindex Winline
+Note that certain usages in a function definition can make it unsuitable
+for inline substitution.  Among these usages are: use of varargs, use of
+alloca, use of variable sized data types (@pxref{Variable Length}),
+use of computed goto (@pxref{Labels as Values}), use of nonlocal goto,
+and nested functions (@pxref{Nested Functions}).  Using @option{-Winline}
+will warn when a function marked @code{inline} could not be substituted,
+and will give the reason for the failure.
+
+Note that in C and Objective-C, unlike C++, the @code{inline} keyword
+does not affect the linkage of the function.
+
+@cindex automatic @code{inline} for C++ member fns
+@cindex @code{inline} automatic for C++ member fns
+@cindex member fns, automatically @code{inline}
+@cindex C++ member fns, automatically @code{inline}
+@opindex fno-default-inline
+GCC automatically inlines member functions defined within the class
+body of C++ programs even if they are not explicitly declared
+@code{inline}.  (You can override this with @option{-fno-default-inline};
+@pxref{C++ Dialect Options,,Options Controlling C++ Dialect}.)
+
+@cindex inline functions, omission of
+@opindex fkeep-inline-functions
+When a function is both inline and @code{static}, if all calls to the
+function are integrated into the caller, and the function's address is
+never used, then the function's own assembler code is never referenced.
+In this case, GCC does not actually output assembler code for the
+function, unless you specify the option @option{-fkeep-inline-functions}.
+Some calls cannot be integrated for various reasons (in particular,
+calls that precede the function's definition cannot be integrated, and
+neither can recursive calls within the definition).  If there is a
+nonintegrated call, then the function is compiled to assembler code as
+usual.  The function must also be compiled as usual if the program
+refers to its address, because that can't be inlined.
+
+@cindex non-static inline function
+When an inline function is not @code{static}, then the compiler must assume
+that there may be calls from other source files; since a global symbol can
+be defined only once in any program, the function must not be defined in
+the other source files, so the calls therein cannot be integrated.
+Therefore, a non-@code{static} inline function is always compiled on its
+own in the usual fashion.
+
+If you specify both @code{inline} and @code{extern} in the function
+definition, then the definition is used only for inlining.  In no case
+is the function compiled on its own, not even if you refer to its
+address explicitly.  Such an address becomes an external reference, as
+if you had only declared the function, and had not defined it.
+
+This combination of @code{inline} and @code{extern} has almost the
+effect of a macro.  The way to use it is to put a function definition in
+a header file with these keywords, and put another copy of the
+definition (lacking @code{inline} and @code{extern}) in a library file.
+The definition in the header file will cause most calls to the function
+to be inlined.  If any uses of the function remain, they will refer to
+the single copy in the library.
+
+For future compatibility with when GCC implements ISO C99 semantics for
+inline functions, it is best to use @code{static inline} only.  (The
+existing semantics will remain available when @option{-std=gnu89} is
+specified, but eventually the default will be @option{-std=gnu99} and
+that will implement the C99 semantics, though it does not do so yet.)
+
+GCC does not inline any functions when not optimizing.  It is not
+clear whether it is better to inline or not, in this case, but we found
+that a correct implementation when not optimizing was difficult.  So we
+did the easy thing, and turned it off.
+
+@node Extended Asm
+@section Assembler Instructions with C Expression Operands
+@cindex extended @code{asm}
+@cindex @code{asm} expressions
+@cindex assembler instructions
+@cindex registers
+
+In an assembler instruction using @code{asm}, you can specify the
+operands of the instruction using C expressions.  This means you need not
+guess which registers or memory locations will contain the data you want
+to use.
+
+You must specify an assembler instruction template much like what
+appears in a machine description, plus an operand constraint string for
+each operand.
+
+For example, here is how to use the 68881's @code{fsinx} instruction:
+
+@example
+asm ("fsinx %1,%0" : "=f" (result) : "f" (angle));
+@end example
+
+@noindent
+Here @code{angle} is the C expression for the input operand while
+@code{result} is that of the output operand.  Each has @samp{"f"} as its
+operand constraint, saying that a floating point register is required.
+The @samp{=} in @samp{=f} indicates that the operand is an output; all
+output operands' constraints must use @samp{=}.  The constraints use the
+same language used in the machine description (@pxref{Constraints}).
+
+Each operand is described by an operand-constraint string followed by
+the C expression in parentheses.  A colon separates the assembler
+template from the first output operand and another separates the last
+output operand from the first input, if any.  Commas separate the
+operands within each group.  The total number of operands is currently
+limited to 30; this limitation may be lifted in some future version of
+GCC.
+
+If there are no output operands but there are input operands, you must
+place two consecutive colons surrounding the place where the output
+operands would go.
+
+As of GCC version 3.1, it is also possible to specify input and output
+operands using symbolic names which can be referenced within the
+assembler code.  These names are specified inside square brackets
+preceding the constraint string, and can be referenced inside the
+assembler code using @code{%[@var{name}]} instead of a percentage sign
+followed by the operand number.  Using named operands the above example
+could look like:
+
+@example
+asm ("fsinx %[angle],%[output]"
+     : [output] "=f" (result)
+     : [angle] "f" (angle));
+@end example
+
+@noindent
+Note that the symbolic operand names have no relation whatsoever to
+other C identifiers.  You may use any name you like, even those of
+existing C symbols, but must ensure that no two operands within the same
+assembler construct use the same symbolic name.
+
+Output operand expressions must be lvalues; the compiler can check this.
+The input operands need not be lvalues.  The compiler cannot check
+whether the operands have data types that are reasonable for the
+instruction being executed.  It does not parse the assembler instruction
+template and does not know what it means or even whether it is valid
+assembler input.  The extended @code{asm} feature is most often used for
+machine instructions the compiler itself does not know exist.  If
+the output expression cannot be directly addressed (for example, it is a
+bit-field), your constraint must allow a register.  In that case, GCC
+will use the register as the output of the @code{asm}, and then store
+that register into the output.
+
+The ordinary output operands must be write-only; GCC will assume that
+the values in these operands before the instruction are dead and need
+not be generated.  Extended asm supports input-output or read-write
+operands.  Use the constraint character @samp{+} to indicate such an
+operand and list it with the output operands.
+
+When the constraints for the read-write operand (or the operand in which
+only some of the bits are to be changed) allows a register, you may, as
+an alternative, logically split its function into two separate operands,
+one input operand and one write-only output operand.  The connection
+between them is expressed by constraints which say they need to be in
+the same location when the instruction executes.  You can use the same C
+expression for both operands, or different expressions.  For example,
+here we write the (fictitious) @samp{combine} instruction with
+@code{bar} as its read-only source operand and @code{foo} as its
+read-write destination:
+
+@example
+asm ("combine %2,%0" : "=r" (foo) : "0" (foo), "g" (bar));
+@end example
+
+@noindent
+The constraint @samp{"0"} for operand 1 says that it must occupy the
+same location as operand 0.  A number in constraint is allowed only in
+an input operand and it must refer to an output operand.
+
+Only a number in the constraint can guarantee that one operand will be in
+the same place as another.  The mere fact that @code{foo} is the value
+of both operands is not enough to guarantee that they will be in the
+same place in the generated assembler code.  The following would not
+work reliably:
+
+@example
+asm ("combine %2,%0" : "=r" (foo) : "r" (foo), "g" (bar));
+@end example
+
+Various optimizations or reloading could cause operands 0 and 1 to be in
+different registers; GCC knows no reason not to do so.  For example, the
+compiler might find a copy of the value of @code{foo} in one register and
+use it for operand 1, but generate the output operand 0 in a different
+register (copying it afterward to @code{foo}'s own address).  Of course,
+since the register for operand 1 is not even mentioned in the assembler
+code, the result will not work, but GCC can't tell that.
+
+As of GCC version 3.1, one may write @code{[@var{name}]} instead of
+the operand number for a matching constraint.  For example:
+
+@example
+asm ("cmoveq %1,%2,%[result]"
+     : [result] "=r"(result)
+     : "r" (test), "r"(new), "[result]"(old));
+@end example
+
+Some instructions clobber specific hard registers.  To describe this,
+write a third colon after the input operands, followed by the names of
+the clobbered hard registers (given as strings).  Here is a realistic
+example for the VAX:
+
+@example
+asm volatile ("movc3 %0,%1,%2"
+              : /* no outputs */
+              : "g" (from), "g" (to), "g" (count)
+              : "r0", "r1", "r2", "r3", "r4", "r5");
+@end example
+
+You may not write a clobber description in a way that overlaps with an
+input or output operand.  For example, you may not have an operand
+describing a register class with one member if you mention that register
+in the clobber list.  There is no way for you to specify that an input
+operand is modified without also specifying it as an output
+operand.  Note that if all the output operands you specify are for this
+purpose (and hence unused), you will then also need to specify
+@code{volatile} for the @code{asm} construct, as described below, to
+prevent GCC from deleting the @code{asm} statement as unused.
+
+If you refer to a particular hardware register from the assembler code,
+you will probably have to list the register after the third colon to
+tell the compiler the register's value is modified.  In some assemblers,
+the register names begin with @samp{%}; to produce one @samp{%} in the
+assembler code, you must write @samp{%%} in the input.
+
+If your assembler instruction can alter the condition code register, add
+@samp{cc} to the list of clobbered registers.  GCC on some machines
+represents the condition codes as a specific hardware register;
+@samp{cc} serves to name this register.  On other machines, the
+condition code is handled differently, and specifying @samp{cc} has no
+effect.  But it is valid no matter what the machine.
+
+If your assembler instruction modifies memory in an unpredictable
+fashion, add @samp{memory} to the list of clobbered registers.  This
+will cause GCC to not keep memory values cached in registers across
+the assembler instruction.  You will also want to add the
+@code{volatile} keyword if the memory affected is not listed in the
+inputs or outputs of the @code{asm}, as the @samp{memory} clobber does
+not count as a side-effect of the @code{asm}.
+
+You can put multiple assembler instructions together in a single
+@code{asm} template, separated by the characters normally used in assembly
+code for the system.  A combination that works in most places is a newline
+to break the line, plus a tab character to move to the instruction field
+(written as @samp{\n\t}).  Sometimes semicolons can be used, if the
+assembler allows semicolons as a line-breaking character.  Note that some
+assembler dialects use semicolons to start a comment.
+The input operands are guaranteed not to use any of the clobbered
+registers, and neither will the output operands' addresses, so you can
+read and write the clobbered registers as many times as you like.  Here
+is an example of multiple instructions in a template; it assumes the
+subroutine @code{_foo} accepts arguments in registers 9 and 10:
+
+@example
+asm ("movl %0,r9\n\tmovl %1,r10\n\tcall _foo"
+     : /* no outputs */
+     : "g" (from), "g" (to)
+     : "r9", "r10");
+@end example
+
+Unless an output operand has the @samp{&} constraint modifier, GCC
+may allocate it in the same register as an unrelated input operand, on
+the assumption the inputs are consumed before the outputs are produced.
+This assumption may be false if the assembler code actually consists of
+more than one instruction.  In such a case, use @samp{&} for each output
+operand that may not overlap an input.  @xref{Modifiers}.
+
+If you want to test the condition code produced by an assembler
+instruction, you must include a branch and a label in the @code{asm}
+construct, as follows:
+
+@example
+asm ("clr %0\n\tfrob %1\n\tbeq 0f\n\tmov #1,%0\n0:"
+     : "g" (result)
+     : "g" (input));
+@end example
+
+@noindent
+This assumes your assembler supports local labels, as the GNU assembler
+and most Unix assemblers do.
+
+Speaking of labels, jumps from one @code{asm} to another are not
+supported.  The compiler's optimizers do not know about these jumps, and
+therefore they cannot take account of them when deciding how to
+optimize.
+
+@cindex macros containing @code{asm}
+Usually the most convenient way to use these @code{asm} instructions is to
+encapsulate them in macros that look like functions.  For example,
+
+@example
+#define sin(x)       \
+(@{ double __value, __arg = (x);   \
+   asm ("fsinx %1,%0": "=f" (__value): "f" (__arg));  \
+   __value; @})
+@end example
+
+@noindent
+Here the variable @code{__arg} is used to make sure that the instruction
+operates on a proper @code{double} value, and to accept only those
+arguments @code{x} which can convert automatically to a @code{double}.
+
+Another way to make sure the instruction operates on the correct data
+type is to use a cast in the @code{asm}.  This is different from using a
+variable @code{__arg} in that it converts more different types.  For
+example, if the desired type were @code{int}, casting the argument to
+@code{int} would accept a pointer with no complaint, while assigning the
+argument to an @code{int} variable named @code{__arg} would warn about
+using a pointer unless the caller explicitly casts it.
+
+If an @code{asm} has output operands, GCC assumes for optimization
+purposes the instruction has no side effects except to change the output
+operands.  This does not mean instructions with a side effect cannot be
+used, but you must be careful, because the compiler may eliminate them
+if the output operands aren't used, or move them out of loops, or
+replace two with one if they constitute a common subexpression.  Also,
+if your instruction does have a side effect on a variable that otherwise
+appears not to change, the old value of the variable may be reused later
+if it happens to be found in a register.
+
+You can prevent an @code{asm} instruction from being deleted, moved
+significantly, or combined, by writing the keyword @code{volatile} after
+the @code{asm}.  For example:
+
+@example
+#define get_and_set_priority(new)              \
+(@{ int __old;                                  \
+   asm volatile ("get_and_set_priority %0, %1" \
+                 : "=g" (__old) : "g" (new));  \
+   __old; @})
+@end example
+
+@noindent
+If you write an @code{asm} instruction with no outputs, GCC will know
+the instruction has side-effects and will not delete the instruction or
+move it outside of loops.
+
+The @code{volatile} keyword indicates that the instruction has
+important side-effects.  GCC will not delete a volatile @code{asm} if
+it is reachable.  (The instruction can still be deleted if GCC can
+prove that control-flow will never reach the location of the
+instruction.)  In addition, GCC will not reschedule instructions
+across a volatile @code{asm} instruction.  For example:
+
+@example
+*(volatile int *)addr = foo;
+asm volatile ("eieio" : : );
+@end example
+
+@noindent
+Assume @code{addr} contains the address of a memory mapped device
+register.  The PowerPC @code{eieio} instruction (Enforce In-order
+Execution of I/O) tells the CPU to make sure that the store to that
+device register happens before it issues any other I/O@.
+
+Note that even a volatile @code{asm} instruction can be moved in ways
+that appear insignificant to the compiler, such as across jump
+instructions.  You can't expect a sequence of volatile @code{asm}
+instructions to remain perfectly consecutive.  If you want consecutive
+output, use a single @code{asm}.  Also, GCC will perform some
+optimizations across a volatile @code{asm} instruction; GCC does not
+``forget everything'' when it encounters a volatile @code{asm}
+instruction the way some other compilers do.
+
+An @code{asm} instruction without any operands or clobbers (an ``old
+style'' @code{asm}) will be treated identically to a volatile
+@code{asm} instruction.
+
+It is a natural idea to look for a way to give access to the condition
+code left by the assembler instruction.  However, when we attempted to
+implement this, we found no way to make it work reliably.  The problem
+is that output operands might need reloading, which would result in
+additional following ``store'' instructions.  On most machines, these
+instructions would alter the condition code before there was time to
+test it.  This problem doesn't arise for ordinary ``test'' and
+``compare'' instructions because they don't have any output operands.
+
+For reasons similar to those described above, it is not possible to give
+an assembler instruction access to the condition code left by previous
+instructions.
+
+If you are writing a header file that should be includable in ISO C
+programs, write @code{__asm__} instead of @code{asm}.  @xref{Alternate
+Keywords}.
+
+@subsection i386 floating point asm operands
+
+There are several rules on the usage of stack-like regs in
+asm_operands insns.  These rules apply only to the operands that are
+stack-like regs:
+
+@enumerate
+@item
+Given a set of input regs that die in an asm_operands, it is
+necessary to know which are implicitly popped by the asm, and
+which must be explicitly popped by gcc.
+
+An input reg that is implicitly popped by the asm must be
+explicitly clobbered, unless it is constrained to match an
+output operand.
+
+@item
+For any input reg that is implicitly popped by an asm, it is
+necessary to know how to adjust the stack to compensate for the pop.
+If any non-popped input is closer to the top of the reg-stack than
+the implicitly popped reg, it would not be possible to know what the
+stack looked like---it's not clear how the rest of the stack ``slides
+up''.
+
+All implicitly popped input regs must be closer to the top of
+the reg-stack than any input that is not implicitly popped.
+
+It is possible that if an input dies in an insn, reload might
+use the input reg for an output reload.  Consider this example:
+
+@example
+asm ("foo" : "=t" (a) : "f" (b));
+@end example
+
+This asm says that input B is not popped by the asm, and that
+the asm pushes a result onto the reg-stack, i.e., the stack is one
+deeper after the asm than it was before.  But, it is possible that
+reload will think that it can use the same reg for both the input and
+the output, if input B dies in this insn.
+
+If any input operand uses the @code{f} constraint, all output reg
+constraints must use the @code{&} earlyclobber.
+
+The asm above would be written as
+
+@example
+asm ("foo" : "=&t" (a) : "f" (b));
+@end example
+
+@item
+Some operands need to be in particular places on the stack.  All
+output operands fall in this category---there is no other way to
+know which regs the outputs appear in unless the user indicates
+this in the constraints.
+
+Output operands must specifically indicate which reg an output
+appears in after an asm.  @code{=f} is not allowed: the operand
+constraints must select a class with a single reg.
+
+@item
+Output operands may not be ``inserted'' between existing stack regs.
+Since no 387 opcode uses a read/write operand, all output operands
+are dead before the asm_operands, and are pushed by the asm_operands.
+It makes no sense to push anywhere but the top of the reg-stack.
+
+Output operands must start at the top of the reg-stack: output
+operands may not ``skip'' a reg.
+
+@item
+Some asm statements may need extra stack space for internal
+calculations.  This can be guaranteed by clobbering stack registers
+unrelated to the inputs and outputs.
+
+@end enumerate
+
+Here are a couple of reasonable asms to want to write.  This asm
+takes one input, which is internally popped, and produces two outputs.
+
+@example
+asm ("fsincos" : "=t" (cos), "=u" (sin) : "0" (inp));
+@end example
+
+This asm takes two inputs, which are popped by the @code{fyl2xp1} opcode,
+and replaces them with one output.  The user must code the @code{st(1)}
+clobber for reg-stack.c to know that @code{fyl2xp1} pops both inputs.
+
+@example
+asm ("fyl2xp1" : "=t" (result) : "0" (x), "u" (y) : "st(1)");
+@end example
+
+@include md.texi
+
+@node Asm Labels
+@section Controlling Names Used in Assembler Code
+@cindex assembler names for identifiers
+@cindex names used in assembler code
+@cindex identifiers, names in assembler code
+
+You can specify the name to be used in the assembler code for a C
+function or variable by writing the @code{asm} (or @code{__asm__})
+keyword after the declarator as follows:
+
+@example
+int foo asm ("myfoo") = 2;
+@end example
+
+@noindent
+This specifies that the name to be used for the variable @code{foo} in
+the assembler code should be @samp{myfoo} rather than the usual
+@samp{_foo}.
+
+On systems where an underscore is normally prepended to the name of a C
+function or variable, this feature allows you to define names for the
+linker that do not start with an underscore.
+
+It does not make sense to use this feature with a non-static local
+variable since such variables do not have assembler names.  If you are
+trying to put the variable in a particular register, see @ref{Explicit
+Reg Vars}.  GCC presently accepts such code with a warning, but will
+probably be changed to issue an error, rather than a warning, in the
+future.
+
+You cannot use @code{asm} in this way in a function @emph{definition}; but
+you can get the same effect by writing a declaration for the function
+before its definition and putting @code{asm} there, like this:
+
+@example
+extern func () asm ("FUNC");
+
+func (x, y)
+     int x, y;
+@dots{}
+@end example
+
+It is up to you to make sure that the assembler names you choose do not
+conflict with any other assembler symbols.  Also, you must not use a
+register name; that would produce completely invalid assembler code.  GCC
+does not as yet have the ability to store static variables in registers.
+Perhaps that will be added.
+
+@node Explicit Reg Vars
+@section Variables in Specified Registers
+@cindex explicit register variables
+@cindex variables in specified registers
+@cindex specified registers
+@cindex registers, global allocation
+
+GNU C allows you to put a few global variables into specified hardware
+registers.  You can also specify the register in which an ordinary
+register variable should be allocated.
+
+@itemize @bullet
+@item
+Global register variables reserve registers throughout the program.
+This may be useful in programs such as programming language
+interpreters which have a couple of global variables that are accessed
+very often.
+
+@item
+Local register variables in specific registers do not reserve the
+registers.  The compiler's data flow analysis is capable of determining
+where the specified registers contain live values, and where they are
+available for other uses.  Stores into local register variables may be deleted
+when they appear to be dead according to dataflow analysis.  References
+to local register variables may be deleted or moved or simplified.
+
+These local variables are sometimes convenient for use with the extended
+@code{asm} feature (@pxref{Extended Asm}), if you want to write one
+output of the assembler instruction directly into a particular register.
+(This will work provided the register you specify fits the constraints
+specified for that operand in the @code{asm}.)
+@end itemize
+
+@menu
+* Global Reg Vars::
+* Local Reg Vars::
+@end menu
+
+@node Global Reg Vars
+@subsection Defining Global Register Variables
+@cindex global register variables
+@cindex registers, global variables in
+
+You can define a global register variable in GNU C like this:
+
+@example
+register int *foo asm ("a5");
+@end example
+
+@noindent
+Here @code{a5} is the name of the register which should be used.  Choose a
+register which is normally saved and restored by function calls on your
+machine, so that library routines will not clobber it.
+
+Naturally the register name is cpu-dependent, so you would need to
+conditionalize your program according to cpu type.  The register
+@code{a5} would be a good choice on a 68000 for a variable of pointer
+type.  On machines with register windows, be sure to choose a ``global''
+register that is not affected magically by the function call mechanism.
+
+In addition, operating systems on one type of cpu may differ in how they
+name the registers; then you would need additional conditionals.  For
+example, some 68000 operating systems call this register @code{%a5}.
+
+Eventually there may be a way of asking the compiler to choose a register
+automatically, but first we need to figure out how it should choose and
+how to enable you to guide the choice.  No solution is evident.
+
+Defining a global register variable in a certain register reserves that
+register entirely for this use, at least within the current compilation.
+The register will not be allocated for any other purpose in the functions
+in the current compilation.  The register will not be saved and restored by
+these functions.  Stores into this register are never deleted even if they
+would appear to be dead, but references may be deleted or moved or
+simplified.
+
+It is not safe to access the global register variables from signal
+handlers, or from more than one thread of control, because the system
+library routines may temporarily use the register for other things (unless
+you recompile them specially for the task at hand).
+
+@cindex @code{qsort}, and global register variables
+It is not safe for one function that uses a global register variable to
+call another such function @code{foo} by way of a third function
+@code{lose} that was compiled without knowledge of this variable (i.e.@: in a
+different source file in which the variable wasn't declared).  This is
+because @code{lose} might save the register and put some other value there.
+For example, you can't expect a global register variable to be available in
+the comparison-function that you pass to @code{qsort}, since @code{qsort}
+might have put something else in that register.  (If you are prepared to
+recompile @code{qsort} with the same global register variable, you can
+solve this problem.)
+
+If you want to recompile @code{qsort} or other source files which do not
+actually use your global register variable, so that they will not use that
+register for any other purpose, then it suffices to specify the compiler
+option @option{-ffixed-@var{reg}}.  You need not actually add a global
+register declaration to their source code.
+
+A function which can alter the value of a global register variable cannot
+safely be called from a function compiled without this variable, because it
+could clobber the value the caller expects to find there on return.
+Therefore, the function which is the entry point into the part of the
+program that uses the global register variable must explicitly save and
+restore the value which belongs to its caller.
+
+@cindex register variable after @code{longjmp}
+@cindex global register after @code{longjmp}
+@cindex value after @code{longjmp}
+@findex longjmp
+@findex setjmp
+On most machines, @code{longjmp} will restore to each global register
+variable the value it had at the time of the @code{setjmp}.  On some
+machines, however, @code{longjmp} will not change the value of global
+register variables.  To be portable, the function that called @code{setjmp}
+should make other arrangements to save the values of the global register
+variables, and to restore them in a @code{longjmp}.  This way, the same
+thing will happen regardless of what @code{longjmp} does.
+
+All global register variable declarations must precede all function
+definitions.  If such a declaration could appear after function
+definitions, the declaration would be too late to prevent the register from
+being used for other purposes in the preceding functions.
+
+Global register variables may not have initial values, because an
+executable file has no means to supply initial contents for a register.
+
+On the Sparc, there are reports that g3 @dots{} g7 are suitable
+registers, but certain library functions, such as @code{getwd}, as well
+as the subroutines for division and remainder, modify g3 and g4.  g1 and
+g2 are local temporaries.
+
+On the 68000, a2 @dots{} a5 should be suitable, as should d2 @dots{} d7.
+Of course, it will not do to use more than a few of those.
+
+@node Local Reg Vars
+@subsection Specifying Registers for Local Variables
+@cindex local variables, specifying registers
+@cindex specifying registers for local variables
+@cindex registers for local variables
+
+You can define a local register variable with a specified register
+like this:
+
+@example
+register int *foo asm ("a5");
+@end example
+
+@noindent
+Here @code{a5} is the name of the register which should be used.  Note
+that this is the same syntax used for defining global register
+variables, but for a local variable it would appear within a function.
+
+Naturally the register name is cpu-dependent, but this is not a
+problem, since specific registers are most often useful with explicit
+assembler instructions (@pxref{Extended Asm}).  Both of these things
+generally require that you conditionalize your program according to
+cpu type.
+
+In addition, operating systems on one type of cpu may differ in how they
+name the registers; then you would need additional conditionals.  For
+example, some 68000 operating systems call this register @code{%a5}.
+
+Defining such a register variable does not reserve the register; it
+remains available for other uses in places where flow control determines
+the variable's value is not live.  However, these registers are made
+unavailable for use in the reload pass; excessive use of this feature
+leaves the compiler too few available registers to compile certain
+functions.
+
+This option does not guarantee that GCC will generate code that has
+this variable in the register you specify at all times.  You may not
+code an explicit reference to this register in an @code{asm} statement
+and assume it will always refer to this variable.
+
+Stores into local register variables may be deleted when they appear to be dead
+according to dataflow analysis.  References to local register variables may
+be deleted or moved or simplified.
+
+@node Alternate Keywords
+@section Alternate Keywords
+@cindex alternate keywords
+@cindex keywords, alternate
+
+The option @option{-traditional} disables certain keywords;
+@option{-ansi} and the various @option{-std} options disable certain
+others.  This causes trouble when you want to use GNU C extensions, or
+ISO C features, in a general-purpose header file that should be usable
+by all programs, including ISO C programs and traditional ones.  The
+keywords @code{asm}, @code{typeof} and @code{inline} cannot be used
+since they won't work in a program compiled with @option{-ansi}
+(although @code{inline} can be used in a program compiled with
+@option{-std=c99}), while the keywords @code{const}, @code{volatile},
+@code{signed}, @code{typeof} and @code{inline} won't work in a program
+compiled with @option{-traditional}.  The ISO C99 keyword
+@code{restrict} is only available when @option{-std=gnu99} (which will
+eventually be the default) or @option{-std=c99} (or the equivalent
+@option{-std=iso9899:1999}) is used.
+
+The way to solve these problems is to put @samp{__} at the beginning and
+end of each problematical keyword.  For example, use @code{__asm__}
+instead of @code{asm}, @code{__const__} instead of @code{const}, and
+@code{__inline__} instead of @code{inline}.
+
+Other C compilers won't accept these alternative keywords; if you want to
+compile with another compiler, you can define the alternate keywords as
+macros to replace them with the customary keywords.  It looks like this:
+
+@example
+#ifndef __GNUC__
+#define __asm__ asm
+#endif
+@end example
+
+@findex __extension__
+@opindex pedantic
+@option{-pedantic} and other options cause warnings for many GNU C extensions.
+You can
+prevent such warnings within one expression by writing
+@code{__extension__} before the expression.  @code{__extension__} has no
+effect aside from this.
+
+@node Incomplete Enums
+@section Incomplete @code{enum} Types
+
+You can define an @code{enum} tag without specifying its possible values.
+This results in an incomplete type, much like what you get if you write
+@code{struct foo} without describing the elements.  A later declaration
+which does specify the possible values completes the type.
+
+You can't allocate variables or storage using the type while it is
+incomplete.  However, you can work with pointers to that type.
+
+This extension may not be very useful, but it makes the handling of
+@code{enum} more consistent with the way @code{struct} and @code{union}
+are handled.
+
+This extension is not supported by GNU C++.
+
+@node Function Names
+@section Function Names as Strings
+@cindex @code{__FUNCTION__} identifier
+@cindex @code{__PRETTY_FUNCTION__} identifier
+@cindex @code{__func__} identifier
+
+GCC predefines two magic identifiers to hold the name of the current
+function.  The identifier @code{__FUNCTION__} holds the name of the function
+as it appears in the source.  The identifier @code{__PRETTY_FUNCTION__}
+holds the name of the function pretty printed in a language specific
+fashion.
+
+These names are always the same in a C function, but in a C++ function
+they may be different.  For example, this program:
+
+@smallexample
+extern "C" @{
+extern int printf (char *, ...);
+@}
+
+class a @{
+ public:
+  sub (int i)
+    @{
+      printf ("__FUNCTION__ = %s\n", __FUNCTION__);
+      printf ("__PRETTY_FUNCTION__ = %s\n", __PRETTY_FUNCTION__);
+    @}
+@};
+
+int
+main (void)
+@{
+  a ax;
+  ax.sub (0);
+  return 0;
+@}
+@end smallexample
+
+@noindent
+gives this output:
+
+@smallexample
+__FUNCTION__ = sub
+__PRETTY_FUNCTION__ = int  a::sub (int)
+@end smallexample
+
+The compiler automagically replaces the identifiers with a string
+literal containing the appropriate name.  Thus, they are neither
+preprocessor macros, like @code{__FILE__} and @code{__LINE__}, nor
+variables.  This means that they catenate with other string literals, and
+that they can be used to initialize char arrays.  For example
+
+@smallexample
+char here[] = "Function " __FUNCTION__ " in " __FILE__;
+@end smallexample
+
+On the other hand, @samp{#ifdef __FUNCTION__} does not have any special
+meaning inside a function, since the preprocessor does not do anything
+special with the identifier @code{__FUNCTION__}.
+
+Note that these semantics are deprecated, and that GCC 3.2 will handle
+@code{__FUNCTION__} and @code{__PRETTY_FUNCTION__} the same way as
+@code{__func__}.  @code{__func__} is defined by the ISO standard C99:
+
+@display
+The identifier @code{__func__} is implicitly declared by the translator
+as if, immediately following the opening brace of each function
+definition, the declaration
+
+@smallexample
+static const char __func__[] = "function-name";
+@end smallexample
+
+appeared, where function-name is the name of the lexically-enclosing
+function.  This name is the unadorned name of the function.
+@end display
+
+By this definition, @code{__func__} is a variable, not a string literal.
+In particular, @code{__func__} does not catenate with other string
+literals.
+
+In @code{C++}, @code{__FUNCTION__} and @code{__PRETTY_FUNCTION__} are
+variables, declared in the same way as @code{__func__}.
+
+@node Return Address
+@section Getting the Return or Frame Address of a Function
+
+These functions may be used to get information about the callers of a
+function.
+
+@deftypefn {Built-in Function} {void *} __builtin_return_address (unsigned int @var{level})
+This function returns the return address of the current function, or of
+one of its callers.  The @var{level} argument is number of frames to
+scan up the call stack.  A value of @code{0} yields the return address
+of the current function, a value of @code{1} yields the return address
+of the caller of the current function, and so forth.
+
+The @var{level} argument must be a constant integer.
+
+On some machines it may be impossible to determine the return address of
+any function other than the current one; in such cases, or when the top
+of the stack has been reached, this function will return @code{0} or a
+random value. In addition, @code{__builtin_frame_address} may be used
+to determine if the top of the stack has been reached.
+
+This function should only be used with a nonzero argument for debugging
+purposes.
+@end deftypefn
+
+@deftypefn {Built-in Function} {void *} __builtin_frame_address (unsigned int @var{level})
+This function is similar to @code{__builtin_return_address}, but it
+returns the address of the function frame rather than the return address
+of the function.  Calling @code{__builtin_frame_address} with a value of
+@code{0} yields the frame address of the current function, a value of
+@code{1} yields the frame address of the caller of the current function,
+and so forth.
+
+The frame is the area on the stack which holds local variables and saved
+registers.  The frame address is normally the address of the first word
+pushed on to the stack by the function.  However, the exact definition
+depends upon the processor and the calling convention.  If the processor
+has a dedicated frame pointer register, and the function has a frame,
+then @code{__builtin_frame_address} will return the value of the frame
+pointer register.
+
+On some machines it may be impossible to determine the frame address of
+any function other than the current one; in such cases, or when the top
+of the stack has been reached, this function will return @code{0} if
+the first frame pointer is properly initialized by the startup code.
+
+This function should only be used with a nonzero argument for debugging
+purposes.
+@end deftypefn
+
+@node Vector Extensions
+@section Using vector instructions through built-in functions
+
+On some targets, the instruction set contains SIMD vector instructions that
+operate on multiple values contained in one large register at the same time.
+For example, on the i386 the MMX, 3Dnow! and SSE extensions can be used
+this way.
+
+The first step in using these extensions is to provide the necessary data
+types.  This should be done using an appropriate @code{typedef}:
+
+@example
+typedef int v4si __attribute__ ((mode(V4SI)));
+@end example
+
+The base type @code{int} is effectively ignored by the compiler, the
+actual properties of the new type @code{v4si} are defined by the
+@code{__attribute__}.  It defines the machine mode to be used; for vector
+types these have the form @code{V@var{n}@var{B}}; @var{n} should be the
+number of elements in the vector, and @var{B} should be the base mode of the
+individual elements.  The following can be used as base modes:
+
+@table @code
+@item QI
+An integer that is as wide as the smallest addressable unit, usually 8 bits.
+@item HI
+An integer, twice as wide as a QI mode integer, usually 16 bits.
+@item SI
+An integer, four times as wide as a QI mode integer, usually 32 bits.
+@item DI
+An integer, eight times as wide as a QI mode integer, usually 64 bits.
+@item SF
+A floating point value, as wide as a SI mode integer, usually 32 bits.
+@item DF
+A floating point value, as wide as a DI mode integer, usually 64 bits.
+@end table
+
+Not all base types or combinations are always valid; which modes can be used
+is determined by the target machine.  For example, if targetting the i386 MMX
+extensions, only @code{V8QI}, @code{V4HI} and @code{V2SI} are allowed modes.
+
+There are no @code{V1xx} vector modes - they would be identical to the
+corresponding base mode.
+
+There is no distinction between signed and unsigned vector modes.  This
+distinction is made by the operations that perform on the vectors, not
+by the data type.
+
+The types defined in this manner are somewhat special, they cannot be
+used with most normal C operations (i.e., a vector addition can @emph{not}
+be represented by a normal addition of two vector type variables).  You
+can declare only variables and use them in function calls and returns, as
+well as in assignments and some casts.  It is possible to cast from one
+vector type to another, provided they are of the same size (in fact, you
+can also cast vectors to and from other datatypes of the same size).
+
+A port that supports vector operations provides a set of built-in functions
+that can be used to operate on vectors.  For example, a function to add two
+vectors and multiply the result by a third could look like this:
+
+@example
+v4si f (v4si a, v4si b, v4si c)
+@{
+  v4si tmp = __builtin_addv4si (a, b);
+  return __builtin_mulv4si (tmp, c);
+@}
+
+@end example
+
+@node Other Builtins
+@section Other built-in functions provided by GCC
+@cindex built-in functions
+@findex __builtin_isgreater
+@findex __builtin_isgreaterequal
+@findex __builtin_isless
+@findex __builtin_islessequal
+@findex __builtin_islessgreater
+@findex __builtin_isunordered
+@findex abort
+@findex abs
+@findex alloca
+@findex bcmp
+@findex bzero
+@findex cimag
+@findex cimagf
+@findex cimagl
+@findex conj
+@findex conjf
+@findex conjl
+@findex cos
+@findex cosf
+@findex cosl
+@findex creal
+@findex crealf
+@findex creall
+@findex exit
+@findex _exit
+@findex _Exit
+@findex fabs
+@findex fabsf
+@findex fabsl
+@findex ffs
+@findex fprintf
+@findex fprintf_unlocked
+@findex fputs
+@findex fputs_unlocked
+@findex imaxabs
+@findex index
+@findex labs
+@findex llabs
+@findex memcmp
+@findex memcpy
+@findex memset
+@findex printf
+@findex printf_unlocked
+@findex rindex
+@findex sin
+@findex sinf
+@findex sinl
+@findex sqrt
+@findex sqrtf
+@findex sqrtl
+@findex strcat
+@findex strchr
+@findex strcmp
+@findex strcpy
+@findex strcspn
+@findex strlen
+@findex strncat
+@findex strncmp
+@findex strncpy
+@findex strpbrk
+@findex strrchr
+@findex strspn
+@findex strstr
+
+GCC provides a large number of built-in functions other than the ones
+mentioned above.  Some of these are for internal use in the processing
+of exceptions or variable-length argument lists and will not be
+documented here because they may change from time to time; we do not
+recommend general use of these functions.
+
+The remaining functions are provided for optimization purposes.
+
+@opindex fno-builtin
+GCC includes built-in versions of many of the functions in the standard
+C library.  The versions prefixed with @code{__builtin_} will always be
+treated as having the same meaning as the C library function even if you
+specify the @option{-fno-builtin} option. (@pxref{C Dialect Options})
+Many of these functions are only optimized in certain cases; if they are
+not optimized in a particular case, a call to the library function will
+be emitted.
+
+@opindex ansi
+@opindex std
+The functions @code{abort}, @code{exit}, @code{_Exit} and @code{_exit}
+are recognized and presumed not to return, but otherwise are not built
+in.  @code{_exit} is not recognized in strict ISO C mode (@option{-ansi},
+@option{-std=c89} or @option{-std=c99}).  @code{_Exit} is not recognized in
+strict C89 mode (@option{-ansi} or @option{-std=c89}).
+
+Outside strict ISO C mode, the functions @code{alloca}, @code{bcmp},
+@code{bzero}, @code{index}, @code{rindex}, @code{ffs}, @code{fputs_unlocked},
+@code{printf_unlocked} and @code{fprintf_unlocked} may be handled as
+built-in functions.  All these functions have corresponding versions
+prefixed with @code{__builtin_}, which may be used even in strict C89
+mode.
+
+The ISO C99 functions @code{conj}, @code{conjf}, @code{conjl},
+@code{creal}, @code{crealf}, @code{creall}, @code{cimag}, @code{cimagf},
+@code{cimagl}, @code{llabs} and @code{imaxabs} are handled as built-in
+functions except in strict ISO C89 mode.  There are also built-in
+versions of the ISO C99 functions @code{cosf}, @code{cosl},
+@code{fabsf}, @code{fabsl}, @code{sinf}, @code{sinl}, @code{sqrtf}, and
+@code{sqrtl}, that are recognized in any mode since ISO C89 reserves
+these names for the purpose to which ISO C99 puts them.  All these
+functions have corresponding versions prefixed with @code{__builtin_}.
+
+The ISO C89 functions @code{abs}, @code{cos}, @code{fabs},
+@code{fprintf}, @code{fputs}, @code{labs}, @code{memcmp}, @code{memcpy},
+@code{memset}, @code{printf}, @code{sin}, @code{sqrt}, @code{strcat},
+@code{strchr}, @code{strcmp}, @code{strcpy}, @code{strcspn},
+@code{strlen}, @code{strncat}, @code{strncmp}, @code{strncpy},
+@code{strpbrk}, @code{strrchr}, @code{strspn}, and @code{strstr} are all
+recognized as built-in functions unless @option{-fno-builtin} is
+specified (or @option{-fno-builtin-@var{function}} is specified for an
+individual function).  All of these functions have corresponding
+versions prefixed with @code{__builtin_}.
+
+GCC provides built-in versions of the ISO C99 floating point comparison
+macros that avoid raising exceptions for unordered operands.  They have
+the same names as the standard macros ( @code{isgreater},
+@code{isgreaterequal}, @code{isless}, @code{islessequal},
+@code{islessgreater}, and @code{isunordered}) , with @code{__builtin_}
+prefixed.  We intend for a library implementor to be able to simply
+@code{#define} each standard macro to its built-in equivalent.
+
+@deftypefn {Built-in Function} int __builtin_types_compatible_p (@var{type1}, @var{type2})
+
+You can use the built-in function @code{__builtin_types_compatible_p} to
+determine whether two types are the same.
+
+This built-in function returns 1 if the unqualified versions of the
+types @var{type1} and @var{type2} (which are types, not expressions) are
+compatible, 0 otherwise.  The result of this built-in function can be
+used in integer constant expressions.
+
+This built-in function ignores top level qualifiers (e.g., @code{const},
+@code{volatile}).  For example, @code{int} is equivalent to @code{const
+int}.
+
+The type @code{int[]} and @code{int[5]} are compatible.  On the other
+hand, @code{int} and @code{char *} are not compatible, even if the size
+of their types, on the particular architecture are the same.  Also, the
+amount of pointer indirection is taken into account when determining
+similarity.  Consequently, @code{short *} is not similar to
+@code{short **}.  Furthermore, two types that are typedefed are
+considered compatible if their underlying types are compatible.
+
+An @code{enum} type is considered to be compatible with another
+@code{enum} type.  For example, @code{enum @{foo, bar@}} is similar to
+@code{enum @{hot, dog@}}.
+
+You would typically use this function in code whose execution varies
+depending on the arguments' types.  For example:
+
+@smallexample
+#define foo(x)                                                        \
+  (@{                                                                 \
+    typeof (x) tmp;                                                   \
+    if (__builtin_types_compatible_p (typeof (x), long double))       \
+      tmp = foo_long_double (tmp);                                    \
+    else if (__builtin_types_compatible_p (typeof (x), double))       \
+      tmp = foo_double (tmp);                                         \
+    else if (__builtin_types_compatible_p (typeof (x), float))        \
+      tmp = foo_float (tmp);                                          \
+    else                                                              \
+      abort ();                                                       \
+    tmp;                                                              \
+  @})
+@end smallexample
+
+@emph{Note:} This construct is only available for C.
+
+@end deftypefn
+
+@deftypefn {Built-in Function} @var{type} __builtin_choose_expr (@var{const_exp}, @var{exp1}, @var{exp2})
+
+You can use the built-in function @code{__builtin_choose_expr} to
+evaluate code depending on the value of a constant expression.  This
+built-in function returns @var{exp1} if @var{const_exp}, which is a
+constant expression that must be able to be determined at compile time,
+is nonzero.  Otherwise it returns 0.
+
+This built-in function is analogous to the @samp{? :} operator in C,
+except that the expression returned has its type unaltered by promotion
+rules.  Also, the built-in function does not evaluate the expression
+that was not chosen.  For example, if @var{const_exp} evaluates to true,
+@var{exp2} is not evaluated even if it has side-effects.
+
+This built-in function can return an lvalue if the chosen argument is an
+lvalue.
+
+If @var{exp1} is returned, the return type is the same as @var{exp1}'s
+type.  Similarly, if @var{exp2} is returned, its return type is the same
+as @var{exp2}.
+
+Example:
+
+@smallexample
+#define foo(x)                                                               \
+  __builtin_choose_expr (__builtin_types_compatible_p (typeof (x), double),  \
+    foo_double (x),                                                          \
+    __builtin_choose_expr (__builtin_types_compatible_p (typeof (x), float), \
+      foo_float (x),                                                         \
+      /* @r{The void expression results in a compile-time error}             \
+         @r{when assigning the result to something.}  */                     \
+      (void)0))
+@end smallexample
+
+@emph{Note:} This construct is only available for C.  Furthermore, the
+unused expression (@var{exp1} or @var{exp2} depending on the value of
+@var{const_exp}) may still generate syntax errors.  This may change in
+future revisions.
+
+@end deftypefn
+
+@deftypefn {Built-in Function} int __builtin_constant_p (@var{exp})
+You can use the built-in function @code{__builtin_constant_p} to
+determine if a value is known to be constant at compile-time and hence
+that GCC can perform constant-folding on expressions involving that
+value.  The argument of the function is the value to test.  The function
+returns the integer 1 if the argument is known to be a compile-time
+constant and 0 if it is not known to be a compile-time constant.  A
+return of 0 does not indicate that the value is @emph{not} a constant,
+but merely that GCC cannot prove it is a constant with the specified
+value of the @option{-O} option.
+
+You would typically use this function in an embedded application where
+memory was a critical resource.  If you have some complex calculation,
+you may want it to be folded if it involves constants, but need to call
+a function if it does not.  For example:
+
+@smallexample
+#define Scale_Value(X)      \
+  (__builtin_constant_p (X) \
+  ? ((X) * SCALE + OFFSET) : Scale (X))
+@end smallexample
+
+You may use this built-in function in either a macro or an inline
+function.  However, if you use it in an inlined function and pass an
+argument of the function as the argument to the built-in, GCC will
+never return 1 when you call the inline function with a string constant
+or compound literal (@pxref{Compound Literals}) and will not return 1
+when you pass a constant numeric value to the inline function unless you
+specify the @option{-O} option.
+
+You may also use @code{__builtin_constant_p} in initializers for static
+data.  For instance, you can write
+
+@smallexample
+static const int table[] = @{
+   __builtin_constant_p (EXPRESSION) ? (EXPRESSION) : -1,
+   /* ... */
+@};
+@end smallexample
+
+@noindent
+This is an acceptable initializer even if @var{EXPRESSION} is not a
+constant expression.  GCC must be more conservative about evaluating the
+built-in in this case, because it has no opportunity to perform
+optimization.
+
+Previous versions of GCC did not accept this built-in in data
+initializers.  The earliest version where it is completely safe is
+3.0.1.
+@end deftypefn
+
+@deftypefn {Built-in Function} long __builtin_expect (long @var{exp}, long @var{c})
+@opindex fprofile-arcs
+You may use @code{__builtin_expect} to provide the compiler with
+branch prediction information.  In general, you should prefer to
+use actual profile feedback for this (@option{-fprofile-arcs}), as
+programmers are notoriously bad at predicting how their programs
+actually perform.  However, there are applications in which this
+data is hard to collect.
+
+The return value is the value of @var{exp}, which should be an
+integral expression.  The value of @var{c} must be a compile-time
+constant.  The semantics of the built-in are that it is expected
+that @var{exp} == @var{c}.  For example:
+
+@smallexample
+if (__builtin_expect (x, 0))
+  foo ();
+@end smallexample
+
+@noindent
+would indicate that we do not expect to call @code{foo}, since
+we expect @code{x} to be zero.  Since you are limited to integral
+expressions for @var{exp}, you should use constructions such as
+
+@smallexample
+if (__builtin_expect (ptr != NULL, 1))
+  error ();
+@end smallexample
+
+@noindent
+when testing pointer or floating-point values.
+@end deftypefn
+
+@deftypefn {Built-in Function} void __builtin_prefetch (const void *@var{addr}, ...)
+This function is used to minimize cache-miss latency by moving data into
+a cache before it is accessed.
+You can insert calls to @code{__builtin_prefetch} into code for which
+you know addresses of data in memory that is likely to be accessed soon.
+If the target supports them, data prefetch instructions will be generated.
+If the prefetch is done early enough before the access then the data will
+be in the cache by the time it is accessed.
+
+The value of @var{addr} is the address of the memory to prefetch.
+There are two optional arguments, @var{rw} and @var{locality}.
+The value of @var{rw} is a compile-time constant one or zero; one
+means that the prefetch is preparing for a write to the memory address
+and zero, the default, means that the prefetch is preparing for a read.
+The value @var{locality} must be a compile-time constant integer between
+zero and three.  A value of zero means that the data has no temporal
+locality, so it need not be left in the cache after the access.  A value
+of three means that the data has a high degree of temporal locality and
+should be left in all levels of cache possible.  Values of one and two
+mean, respectively, a low or moderate degree of temporal locality.  The
+default is three.
+
+@smallexample
+for (i = 0; i < n; i++)
+  @{
+    a[i] = a[i] + b[i];
+    __builtin_prefetch (&a[i+j], 1, 1);
+    __builtin_prefetch (&b[i+j], 0, 1);
+    /* ... */
+  @}
+@end smallexample
+
+Data prefetch does not generate faults if @var{addr} is invalid, but 
+the address expression itself must be valid.  For example, a prefetch
+of @code{p->next} will not fault if @code{p->next} is not a valid
+address, but evaluation will fault if @code{p} is not a valid address.
+
+If the target does not support data prefetch, the address expression
+is evaluated if it includes side effects but no other code is generated
+and GCC does not issue a warning.
+@end deftypefn
+
+@node Target Builtins
+@section Built-in Functions Specific to Particular Target Machines
+
+On some target machines, GCC supports many built-in functions specific
+to those machines.  Generally these generate calls to specific machine
+instructions, but allow the compiler to schedule those calls.
+
+@menu
+* X86 Built-in Functions::
+* PowerPC AltiVec Built-in Functions::
+@end menu
+
+@node X86 Built-in Functions
+@subsection X86 Built-in Functions
+
+These built-in functions are available for the i386 and x86-64 family
+of computers, depending on the command-line switches used.
+
+The following machine modes are available for use with MMX built-in functions
+(@pxref{Vector Extensions}): @code{V2SI} for a vector of two 32-bit integers,
+@code{V4HI} for a vector of four 16-bit integers, and @code{V8QI} for a
+vector of eight 8-bit integers.  Some of the built-in functions operate on
+MMX registers as a whole 64-bit entity, these use @code{DI} as their mode.
+
+If 3Dnow extensions are enabled, @code{V2SF} is used as a mode for a vector
+of two 32-bit floating point values.
+
+If SSE extensions are enabled, @code{V4SF} is used for a vector of four 32-bit
+floating point values.  Some instructions use a vector of four 32-bit
+integers, these use @code{V4SI}.  Finally, some instructions operate on an
+entire vector register, interpreting it as a 128-bit integer, these use mode
+@code{TI}.
+
+The following built-in functions are made available by @option{-mmmx}.
+All of them generate the machine instruction that is part of the name.
+
+@example
+v8qi __builtin_ia32_paddb (v8qi, v8qi)
+v4hi __builtin_ia32_paddw (v4hi, v4hi)
+v2si __builtin_ia32_paddd (v2si, v2si)
+v8qi __builtin_ia32_psubb (v8qi, v8qi)
+v4hi __builtin_ia32_psubw (v4hi, v4hi)
+v2si __builtin_ia32_psubd (v2si, v2si)
+v8qi __builtin_ia32_paddsb (v8qi, v8qi)
+v4hi __builtin_ia32_paddsw (v4hi, v4hi)
+v8qi __builtin_ia32_psubsb (v8qi, v8qi)
+v4hi __builtin_ia32_psubsw (v4hi, v4hi)
+v8qi __builtin_ia32_paddusb (v8qi, v8qi)
+v4hi __builtin_ia32_paddusw (v4hi, v4hi)
+v8qi __builtin_ia32_psubusb (v8qi, v8qi)
+v4hi __builtin_ia32_psubusw (v4hi, v4hi)
+v4hi __builtin_ia32_pmullw (v4hi, v4hi)
+v4hi __builtin_ia32_pmulhw (v4hi, v4hi)
+di __builtin_ia32_pand (di, di)
+di __builtin_ia32_pandn (di,di)
+di __builtin_ia32_por (di, di)
+di __builtin_ia32_pxor (di, di)
+v8qi __builtin_ia32_pcmpeqb (v8qi, v8qi)
+v4hi __builtin_ia32_pcmpeqw (v4hi, v4hi)
+v2si __builtin_ia32_pcmpeqd (v2si, v2si)
+v8qi __builtin_ia32_pcmpgtb (v8qi, v8qi)
+v4hi __builtin_ia32_pcmpgtw (v4hi, v4hi)
+v2si __builtin_ia32_pcmpgtd (v2si, v2si)
+v8qi __builtin_ia32_punpckhbw (v8qi, v8qi)
+v4hi __builtin_ia32_punpckhwd (v4hi, v4hi)
+v2si __builtin_ia32_punpckhdq (v2si, v2si)
+v8qi __builtin_ia32_punpcklbw (v8qi, v8qi)
+v4hi __builtin_ia32_punpcklwd (v4hi, v4hi)
+v2si __builtin_ia32_punpckldq (v2si, v2si)
+v8qi __builtin_ia32_packsswb (v4hi, v4hi)
+v4hi __builtin_ia32_packssdw (v2si, v2si)
+v8qi __builtin_ia32_packuswb (v4hi, v4hi)
+@end example
+
+The following built-in functions are made available either with
+@option{-msse}, or with a combination of @option{-m3dnow} and
+@option{-march=athlon}.  All of them generate the machine
+instruction that is part of the name.
+
+@example
+v4hi __builtin_ia32_pmulhuw (v4hi, v4hi)
+v8qi __builtin_ia32_pavgb (v8qi, v8qi)
+v4hi __builtin_ia32_pavgw (v4hi, v4hi)
+v4hi __builtin_ia32_psadbw (v8qi, v8qi)
+v8qi __builtin_ia32_pmaxub (v8qi, v8qi)
+v4hi __builtin_ia32_pmaxsw (v4hi, v4hi)
+v8qi __builtin_ia32_pminub (v8qi, v8qi)
+v4hi __builtin_ia32_pminsw (v4hi, v4hi)
+int __builtin_ia32_pextrw (v4hi, int)
+v4hi __builtin_ia32_pinsrw (v4hi, int, int)
+int __builtin_ia32_pmovmskb (v8qi)
+void __builtin_ia32_maskmovq (v8qi, v8qi, char *)
+void __builtin_ia32_movntq (di *, di)
+void __builtin_ia32_sfence (void)
+@end example
+
+The following built-in functions are available when @option{-msse} is used.
+All of them generate the machine instruction that is part of the name.
+
+@example
+int __builtin_ia32_comieq (v4sf, v4sf)
+int __builtin_ia32_comineq (v4sf, v4sf)
+int __builtin_ia32_comilt (v4sf, v4sf)
+int __builtin_ia32_comile (v4sf, v4sf)
+int __builtin_ia32_comigt (v4sf, v4sf)
+int __builtin_ia32_comige (v4sf, v4sf)
+int __builtin_ia32_ucomieq (v4sf, v4sf)
+int __builtin_ia32_ucomineq (v4sf, v4sf)
+int __builtin_ia32_ucomilt (v4sf, v4sf)
+int __builtin_ia32_ucomile (v4sf, v4sf)
+int __builtin_ia32_ucomigt (v4sf, v4sf)
+int __builtin_ia32_ucomige (v4sf, v4sf)
+v4sf __builtin_ia32_addps (v4sf, v4sf)
+v4sf __builtin_ia32_subps (v4sf, v4sf)
+v4sf __builtin_ia32_mulps (v4sf, v4sf)
+v4sf __builtin_ia32_divps (v4sf, v4sf)
+v4sf __builtin_ia32_addss (v4sf, v4sf)
+v4sf __builtin_ia32_subss (v4sf, v4sf)
+v4sf __builtin_ia32_mulss (v4sf, v4sf)
+v4sf __builtin_ia32_divss (v4sf, v4sf)
+v4si __builtin_ia32_cmpeqps (v4sf, v4sf)
+v4si __builtin_ia32_cmpltps (v4sf, v4sf)
+v4si __builtin_ia32_cmpleps (v4sf, v4sf)
+v4si __builtin_ia32_cmpgtps (v4sf, v4sf)
+v4si __builtin_ia32_cmpgeps (v4sf, v4sf)
+v4si __builtin_ia32_cmpunordps (v4sf, v4sf)
+v4si __builtin_ia32_cmpneqps (v4sf, v4sf)
+v4si __builtin_ia32_cmpnltps (v4sf, v4sf)
+v4si __builtin_ia32_cmpnleps (v4sf, v4sf)
+v4si __builtin_ia32_cmpngtps (v4sf, v4sf)
+v4si __builtin_ia32_cmpngeps (v4sf, v4sf)
+v4si __builtin_ia32_cmpordps (v4sf, v4sf)
+v4si __builtin_ia32_cmpeqss (v4sf, v4sf)
+v4si __builtin_ia32_cmpltss (v4sf, v4sf)
+v4si __builtin_ia32_cmpless (v4sf, v4sf)
+v4si __builtin_ia32_cmpgtss (v4sf, v4sf)
+v4si __builtin_ia32_cmpgess (v4sf, v4sf)
+v4si __builtin_ia32_cmpunordss (v4sf, v4sf)
+v4si __builtin_ia32_cmpneqss (v4sf, v4sf)
+v4si __builtin_ia32_cmpnlts (v4sf, v4sf)
+v4si __builtin_ia32_cmpnless (v4sf, v4sf)
+v4si __builtin_ia32_cmpngtss (v4sf, v4sf)
+v4si __builtin_ia32_cmpngess (v4sf, v4sf)
+v4si __builtin_ia32_cmpordss (v4sf, v4sf)
+v4sf __builtin_ia32_maxps (v4sf, v4sf)
+v4sf __builtin_ia32_maxss (v4sf, v4sf)
+v4sf __builtin_ia32_minps (v4sf, v4sf)
+v4sf __builtin_ia32_minss (v4sf, v4sf)
+v4sf __builtin_ia32_andps (v4sf, v4sf)
+v4sf __builtin_ia32_andnps (v4sf, v4sf)
+v4sf __builtin_ia32_orps (v4sf, v4sf)
+v4sf __builtin_ia32_xorps (v4sf, v4sf)
+v4sf __builtin_ia32_movss (v4sf, v4sf)
+v4sf __builtin_ia32_movhlps (v4sf, v4sf)
+v4sf __builtin_ia32_movlhps (v4sf, v4sf)
+v4sf __builtin_ia32_unpckhps (v4sf, v4sf)
+v4sf __builtin_ia32_unpcklps (v4sf, v4sf)
+v4sf __builtin_ia32_cvtpi2ps (v4sf, v2si)
+v4sf __builtin_ia32_cvtsi2ss (v4sf, int)
+v2si __builtin_ia32_cvtps2pi (v4sf)
+int __builtin_ia32_cvtss2si (v4sf)
+v2si __builtin_ia32_cvttps2pi (v4sf)
+int __builtin_ia32_cvttss2si (v4sf)
+v4sf __builtin_ia32_rcpps (v4sf)
+v4sf __builtin_ia32_rsqrtps (v4sf)
+v4sf __builtin_ia32_sqrtps (v4sf)
+v4sf __builtin_ia32_rcpss (v4sf)
+v4sf __builtin_ia32_rsqrtss (v4sf)
+v4sf __builtin_ia32_sqrtss (v4sf)
+v4sf __builtin_ia32_shufps (v4sf, v4sf, int)
+void __builtin_ia32_movntps (float *, v4sf)
+int __builtin_ia32_movmskps (v4sf)
+@end example
+
+The following built-in functions are available when @option{-msse} is used.
+
+@table @code
+@item v4sf __builtin_ia32_loadaps (float *)
+Generates the @code{movaps} machine instruction as a load from memory.
+@item void __builtin_ia32_storeaps (float *, v4sf)
+Generates the @code{movaps} machine instruction as a store to memory.
+@item v4sf __builtin_ia32_loadups (float *)
+Generates the @code{movups} machine instruction as a load from memory.
+@item void __builtin_ia32_storeups (float *, v4sf)
+Generates the @code{movups} machine instruction as a store to memory.
+@item v4sf __builtin_ia32_loadsss (float *)
+Generates the @code{movss} machine instruction as a load from memory.
+@item void __builtin_ia32_storess (float *, v4sf)
+Generates the @code{movss} machine instruction as a store to memory.
+@item v4sf __builtin_ia32_loadhps (v4sf, v2si *)
+Generates the @code{movhps} machine instruction as a load from memory.
+@item v4sf __builtin_ia32_loadlps (v4sf, v2si *)
+Generates the @code{movlps} machine instruction as a load from memory
+@item void __builtin_ia32_storehps (v4sf, v2si *)
+Generates the @code{movhps} machine instruction as a store to memory.
+@item void __builtin_ia32_storelps (v4sf, v2si *)
+Generates the @code{movlps} machine instruction as a store to memory.
+@end table
+
+The following built-in functions are available when @option{-m3dnow} is used.
+All of them generate the machine instruction that is part of the name.
+
+@example
+void __builtin_ia32_femms (void)
+v8qi __builtin_ia32_pavgusb (v8qi, v8qi)
+v2si __builtin_ia32_pf2id (v2sf)
+v2sf __builtin_ia32_pfacc (v2sf, v2sf)
+v2sf __builtin_ia32_pfadd (v2sf, v2sf)
+v2si __builtin_ia32_pfcmpeq (v2sf, v2sf)
+v2si __builtin_ia32_pfcmpge (v2sf, v2sf)
+v2si __builtin_ia32_pfcmpgt (v2sf, v2sf)
+v2sf __builtin_ia32_pfmax (v2sf, v2sf)
+v2sf __builtin_ia32_pfmin (v2sf, v2sf)
+v2sf __builtin_ia32_pfmul (v2sf, v2sf)
+v2sf __builtin_ia32_pfrcp (v2sf)
+v2sf __builtin_ia32_pfrcpit1 (v2sf, v2sf)
+v2sf __builtin_ia32_pfrcpit2 (v2sf, v2sf)
+v2sf __builtin_ia32_pfrsqrt (v2sf)
+v2sf __builtin_ia32_pfrsqrtit1 (v2sf, v2sf)
+v2sf __builtin_ia32_pfsub (v2sf, v2sf)
+v2sf __builtin_ia32_pfsubr (v2sf, v2sf)
+v2sf __builtin_ia32_pi2fd (v2si)
+v4hi __builtin_ia32_pmulhrw (v4hi, v4hi)
+@end example
+
+The following built-in functions are available when both @option{-m3dnow}
+and @option{-march=athlon} are used.  All of them generate the machine
+instruction that is part of the name.
+
+@example
+v2si __builtin_ia32_pf2iw (v2sf)
+v2sf __builtin_ia32_pfnacc (v2sf, v2sf)
+v2sf __builtin_ia32_pfpnacc (v2sf, v2sf)
+v2sf __builtin_ia32_pi2fw (v2si)
+v2sf __builtin_ia32_pswapdsf (v2sf)
+v2si __builtin_ia32_pswapdsi (v2si)
+@end example
+
+@node PowerPC AltiVec Built-in Functions
+@subsection PowerPC AltiVec Built-in Functions
+
+These built-in functions are available for the PowerPC family
+of computers, depending on the command-line switches used.
+
+The following machine modes are available for use with AltiVec built-in
+functions (@pxref{Vector Extensions}): @code{V4SI} for a vector of four
+32-bit integers, @code{V4SF} for a vector of four 32-bit floating point
+numbers, @code{V8HI} for a vector of eight 16-bit integers, and
+@code{V16QI} for a vector of sixteen 8-bit integers.
+
+The following functions are made available by including
+@code{<altivec.h>} and using @option{-maltivec} and
+@option{-mabi=altivec}.  The functions implement the functionality
+described in Motorola's AltiVec Programming Interface Manual.
+
+@smallexample
+vector signed char vec_abs (vector signed char, vector signed char);
+vector signed short vec_abs (vector signed short, vector signed short);
+vector signed int vec_abs (vector signed int, vector signed int);
+vector signed float vec_abs (vector signed float, vector signed float);
+
+vector signed char vec_abss (vector signed char, vector signed char);
+vector signed short vec_abss (vector signed short, vector signed short);
+
+vector signed char vec_add (vector signed char, vector signed char);
+vector unsigned char vec_add (vector signed char, vector unsigned char);
+
+vector unsigned char vec_add (vector unsigned char, vector signed char);
+
+vector unsigned char vec_add (vector unsigned char, vector unsigned char);
+vector signed short vec_add (vector signed short, vector signed short);
+vector unsigned short vec_add (vector signed short, vector unsigned short);
+vector unsigned short vec_add (vector unsigned short, vector signed short);
+vector unsigned short vec_add (vector unsigned short, vector unsigned short);
+vector signed int vec_add (vector signed int, vector signed int);
+vector unsigned int vec_add (vector signed int, vector unsigned int);
+vector unsigned int vec_add (vector unsigned int, vector signed int);
+vector unsigned int vec_add (vector unsigned int, vector unsigned int);
+vector float vec_add (vector float, vector float);
+
+vector unsigned int vec_addc (vector unsigned int, vector unsigned int);
+
+vector unsigned char vec_adds (vector signed char, vector unsigned char);
+vector unsigned char vec_adds (vector unsigned char, vector signed char);
+vector unsigned char vec_adds (vector unsigned char, vector unsigned char);
+vector signed char vec_adds (vector signed char, vector signed char);
+vector unsigned short vec_adds (vector signed short, vector unsigned short);
+vector unsigned short vec_adds (vector unsigned short, vector signed short);
+vector unsigned short vec_adds (vector unsigned short, vector unsigned short);
+vector signed short vec_adds (vector signed short, vector signed short);
+
+vector unsigned int vec_adds (vector signed int, vector unsigned int);
+vector unsigned int vec_adds (vector unsigned int, vector signed int);
+vector unsigned int vec_adds (vector unsigned int, vector unsigned int);
+
+vector signed int vec_adds (vector signed int, vector signed int);
+
+vector float vec_and (vector float, vector float);
+vector float vec_and (vector float, vector signed int);
+vector float vec_and (vector signed int, vector float);
+vector signed int vec_and (vector signed int, vector signed int);
+vector unsigned int vec_and (vector signed int, vector unsigned int);
+vector unsigned int vec_and (vector unsigned int, vector signed int);
+vector unsigned int vec_and (vector unsigned int, vector unsigned int);
+vector signed short vec_and (vector signed short, vector signed short);
+vector unsigned short vec_and (vector signed short, vector unsigned short);
+vector unsigned short vec_and (vector unsigned short, vector signed short);
+vector unsigned short vec_and (vector unsigned short, vector unsigned short);
+vector signed char vec_and (vector signed char, vector signed char);
+vector unsigned char vec_and (vector signed char, vector unsigned char);
+
+vector unsigned char vec_and (vector unsigned char, vector signed char);
+
+vector unsigned char vec_and (vector unsigned char, vector unsigned char);
+
+vector float vec_andc (vector float, vector float);
+vector float vec_andc (vector float, vector signed int);
+vector float vec_andc (vector signed int, vector float);
+vector signed int vec_andc (vector signed int, vector signed int);
+vector unsigned int vec_andc (vector signed int, vector unsigned int);
+vector unsigned int vec_andc (vector unsigned int, vector signed int);
+vector unsigned int vec_andc (vector unsigned int, vector unsigned int);
+
+vector signed short vec_andc (vector signed short, vector signed short);
+
+vector unsigned short vec_andc (vector signed short, vector unsigned short);
+vector unsigned short vec_andc (vector unsigned short, vector signed short);
+vector unsigned short vec_andc (vector unsigned short, vector unsigned short);
+vector signed char vec_andc (vector signed char, vector signed char);
+vector unsigned char vec_andc (vector signed char, vector unsigned char);
+vector unsigned char vec_andc (vector unsigned char, vector signed char);
+vector unsigned char vec_andc (vector unsigned char, vector unsigned char);
+
+vector unsigned char vec_avg (vector unsigned char, vector unsigned char);
+vector signed char vec_avg (vector signed char, vector signed char);
+vector unsigned short vec_avg (vector unsigned short, vector unsigned short);
+vector signed short vec_avg (vector signed short, vector signed short);
+vector unsigned int vec_avg (vector unsigned int, vector unsigned int);
+vector signed int vec_avg (vector signed int, vector signed int);
+
+vector float vec_ceil (vector float);
+
+vector signed int vec_cmpb (vector float, vector float);
+
+vector signed char vec_cmpeq (vector signed char, vector signed char);
+vector signed char vec_cmpeq (vector unsigned char, vector unsigned char);
+vector signed short vec_cmpeq (vector signed short, vector signed short);
+vector signed short vec_cmpeq (vector unsigned short, vector unsigned short);
+vector signed int vec_cmpeq (vector signed int, vector signed int);
+vector signed int vec_cmpeq (vector unsigned int, vector unsigned int);
+vector signed int vec_cmpeq (vector float, vector float);
+
+vector signed int vec_cmpge (vector float, vector float);
+
+vector signed char vec_cmpgt (vector unsigned char, vector unsigned char);
+vector signed char vec_cmpgt (vector signed char, vector signed char);
+vector signed short vec_cmpgt (vector unsigned short, vector unsigned short);
+vector signed short vec_cmpgt (vector signed short, vector signed short);
+vector signed int vec_cmpgt (vector unsigned int, vector unsigned int);
+vector signed int vec_cmpgt (vector signed int, vector signed int);
+vector signed int vec_cmpgt (vector float, vector float);
+
+vector signed int vec_cmple (vector float, vector float);
+
+vector signed char vec_cmplt (vector unsigned char, vector unsigned char);
+vector signed char vec_cmplt (vector signed char, vector signed char);
+vector signed short vec_cmplt (vector unsigned short, vector unsigned short);
+vector signed short vec_cmplt (vector signed short, vector signed short);
+vector signed int vec_cmplt (vector unsigned int, vector unsigned int);
+vector signed int vec_cmplt (vector signed int, vector signed int);
+vector signed int vec_cmplt (vector float, vector float);
+
+vector float vec_ctf (vector unsigned int, const char);
+vector float vec_ctf (vector signed int, const char);
+
+vector signed int vec_cts (vector float, const char);
+
+vector unsigned int vec_ctu (vector float, const char);
+
+void vec_dss (const char);
+
+void vec_dssall (void);
+
+void vec_dst (void *, int, const char);
+
+void vec_dstst (void *, int, const char);
+
+void vec_dststt (void *, int, const char);
+
+void vec_dstt (void *, int, const char);
+
+vector float vec_expte (vector float, vector float);
+
+vector float vec_floor (vector float, vector float);
+
+vector float vec_ld (int, vector float *);
+vector float vec_ld (int, float *):
+vector signed int vec_ld (int, int *);
+vector signed int vec_ld (int, vector signed int *);
+vector unsigned int vec_ld (int, vector unsigned int *);
+vector unsigned int vec_ld (int, unsigned int *);
+vector signed short vec_ld (int, short *, vector signed short *);
+vector unsigned short vec_ld (int, unsigned short *, vector unsigned short *);
+vector signed char vec_ld (int, signed char *);
+vector signed char vec_ld (int, vector signed char *);
+vector unsigned char vec_ld (int, unsigned char *);
+vector unsigned char vec_ld (int, vector unsigned char *);
+
+vector signed char vec_lde (int, signed char *);
+vector unsigned char vec_lde (int, unsigned char *);
+vector signed short vec_lde (int, short *);
+vector unsigned short vec_lde (int, unsigned short *);
+vector float vec_lde (int, float *);
+vector signed int vec_lde (int, int *);
+vector unsigned int vec_lde (int, unsigned int *);
+
+void float vec_ldl (int, float *);
+void float vec_ldl (int, vector float *);
+void signed int vec_ldl (int, vector signed int *);
+void signed int vec_ldl (int, int *);
+void unsigned int vec_ldl (int, unsigned int *);
+void unsigned int vec_ldl (int, vector unsigned int *);
+void signed short vec_ldl (int, vector signed short *);
+void signed short vec_ldl (int, short *);
+void unsigned short vec_ldl (int, vector unsigned short *);
+void unsigned short vec_ldl (int, unsigned short *);
+void signed char vec_ldl (int, vector signed char *);
+void signed char vec_ldl (int, signed char *);
+void unsigned char vec_ldl (int, vector unsigned char *);
+void unsigned char vec_ldl (int, unsigned char *);
+
+vector float vec_loge (vector float);
+
+vector unsigned char vec_lvsl (int, void *, int *);
+
+vector unsigned char vec_lvsr (int, void *, int *);
+
+vector float vec_madd (vector float, vector float, vector float);
+
+vector signed short vec_madds (vector signed short, vector signed short, vector signed short);
+
+vector unsigned char vec_max (vector signed char, vector unsigned char);
+
+vector unsigned char vec_max (vector unsigned char, vector signed char);
+
+vector unsigned char vec_max (vector unsigned char, vector unsigned char);
+vector signed char vec_max (vector signed char, vector signed char);
+vector unsigned short vec_max (vector signed short, vector unsigned short);
+vector unsigned short vec_max (vector unsigned short, vector signed short);
+vector unsigned short vec_max (vector unsigned short, vector unsigned short);
+vector signed short vec_max (vector signed short, vector signed short);
+vector unsigned int vec_max (vector signed int, vector unsigned int);
+vector unsigned int vec_max (vector unsigned int, vector signed int);
+vector unsigned int vec_max (vector unsigned int, vector unsigned int);
+vector signed int vec_max (vector signed int, vector signed int);
+vector float vec_max (vector float, vector float);
+
+vector signed char vec_mergeh (vector signed char, vector signed char);
+vector unsigned char vec_mergeh (vector unsigned char, vector unsigned char);
+vector signed short vec_mergeh (vector signed short, vector signed short);
+vector unsigned short vec_mergeh (vector unsigned short, vector unsigned short);
+vector float vec_mergeh (vector float, vector float);
+vector signed int vec_mergeh (vector signed int, vector signed int);
+vector unsigned int vec_mergeh (vector unsigned int, vector unsigned int);
+
+vector signed char vec_mergel (vector signed char, vector signed char);
+vector unsigned char vec_mergel (vector unsigned char, vector unsigned char);
+vector signed short vec_mergel (vector signed short, vector signed short);
+vector unsigned short vec_mergel (vector unsigned short, vector unsigned short);
+vector float vec_mergel (vector float, vector float);
+vector signed int vec_mergel (vector signed int, vector signed int);
+vector unsigned int vec_mergel (vector unsigned int, vector unsigned int);
+
+vector unsigned short vec_mfvscr (void);
+
+vector unsigned char vec_min (vector signed char, vector unsigned char);
+
+vector unsigned char vec_min (vector unsigned char, vector signed char);
+
+vector unsigned char vec_min (vector unsigned char, vector unsigned char);
+vector signed char vec_min (vector signed char, vector signed char);
+vector unsigned short vec_min (vector signed short, vector unsigned short);
+vector unsigned short vec_min (vector unsigned short, vector signed short);
+vector unsigned short vec_min (vector unsigned short, vector unsigned short);
+vector signed short vec_min (vector signed short, vector signed short);
+vector unsigned int vec_min (vector signed int, vector unsigned int);
+vector unsigned int vec_min (vector unsigned int, vector signed int);
+vector unsigned int vec_min (vector unsigned int, vector unsigned int);
+vector signed int vec_min (vector signed int, vector signed int);
+vector float vec_min (vector float, vector float);
+
+vector signed short vec_mladd (vector signed short, vector signed short, vector signed short);
+vector signed short vec_mladd (vector signed short, vector unsigned short, vector unsigned short);
+vector signed short vec_mladd (vector unsigned short, vector signed short, vector signed short);
+vector unsigned short vec_mladd (vector unsigned short, vector unsigned short, vector unsigned short);
+
+vector signed short vec_mradds (vector signed short, vector signed short, vector signed short);
+
+vector unsigned int vec_msum (vector unsigned char, vector unsigned char, vector unsigned int);
+vector signed int vec_msum (vector signed char, vector unsigned char, vector signed int);
+vector unsigned int vec_msum (vector unsigned short, vector unsigned short, vector unsigned int);
+vector signed int vec_msum (vector signed short, vector signed short, vector signed int);
+
+vector unsigned int vec_msums (vector unsigned short, vector unsigned short, vector unsigned int);
+vector signed int vec_msums (vector signed short, vector signed short, vector signed int);
+
+void vec_mtvscr (vector signed int);
+void vec_mtvscr (vector unsigned int);
+void vec_mtvscr (vector signed short);
+void vec_mtvscr (vector unsigned short);
+void vec_mtvscr (vector signed char);
+void vec_mtvscr (vector unsigned char);
+
+vector unsigned short vec_mule (vector unsigned char, vector unsigned char);
+vector signed short vec_mule (vector signed char, vector signed char);
+vector unsigned int vec_mule (vector unsigned short, vector unsigned short);
+vector signed int vec_mule (vector signed short, vector signed short);
+
+vector unsigned short vec_mulo (vector unsigned char, vector unsigned char);
+vector signed short vec_mulo (vector signed char, vector signed char);
+vector unsigned int vec_mulo (vector unsigned short, vector unsigned short);
+vector signed int vec_mulo (vector signed short, vector signed short);
+
+vector float vec_nmsub (vector float, vector float, vector float);
+
+vector float vec_nor (vector float, vector float);
+vector signed int vec_nor (vector signed int, vector signed int);
+vector unsigned int vec_nor (vector unsigned int, vector unsigned int);
+vector signed short vec_nor (vector signed short, vector signed short);
+vector unsigned short vec_nor (vector unsigned short, vector unsigned short);
+vector signed char vec_nor (vector signed char, vector signed char);
+vector unsigned char vec_nor (vector unsigned char, vector unsigned char);
+
+vector float vec_or (vector float, vector float);
+vector float vec_or (vector float, vector signed int);
+vector float vec_or (vector signed int, vector float);
+vector signed int vec_or (vector signed int, vector signed int);
+vector unsigned int vec_or (vector signed int, vector unsigned int);
+vector unsigned int vec_or (vector unsigned int, vector signed int);
+vector unsigned int vec_or (vector unsigned int, vector unsigned int);
+vector signed short vec_or (vector signed short, vector signed short);
+vector unsigned short vec_or (vector signed short, vector unsigned short);
+vector unsigned short vec_or (vector unsigned short, vector signed short);
+vector unsigned short vec_or (vector unsigned short, vector unsigned short);
+vector signed char vec_or (vector signed char, vector signed char);
+vector unsigned char vec_or (vector signed char, vector unsigned char);
+vector unsigned char vec_or (vector unsigned char, vector signed char);
+vector unsigned char vec_or (vector unsigned char, vector unsigned char);
+
+vector signed char vec_pack (vector signed short, vector signed short);
+vector unsigned char vec_pack (vector unsigned short, vector unsigned short);
+vector signed short vec_pack (vector signed int, vector signed int);
+vector unsigned short vec_pack (vector unsigned int, vector unsigned int);
+
+vector signed short vec_packpx (vector unsigned int, vector unsigned int);
+
+vector unsigned char vec_packs (vector unsigned short, vector unsigned short);
+vector signed char vec_packs (vector signed short, vector signed short);
+
+vector unsigned short vec_packs (vector unsigned int, vector unsigned int);
+vector signed short vec_packs (vector signed int, vector signed int);
+
+vector unsigned char vec_packsu (vector unsigned short, vector unsigned short);
+vector unsigned char vec_packsu (vector signed short, vector signed short);
+vector unsigned short vec_packsu (vector unsigned int, vector unsigned int);
+vector unsigned short vec_packsu (vector signed int, vector signed int);
+
+vector float vec_perm (vector float, vector float, vector unsigned char);
+vector signed int vec_perm (vector signed int, vector signed int, vector unsigned char);
+vector unsigned int vec_perm (vector unsigned int, vector unsigned int, vector unsigned char);
+vector signed short vec_perm (vector signed short, vector signed short, vector unsigned char);
+vector unsigned short vec_perm (vector unsigned short, vector unsigned short, vector unsigned char);
+vector signed char vec_perm (vector signed char, vector signed char, vector unsigned char);
+vector unsigned char vec_perm (vector unsigned char, vector unsigned char, vector unsigned char);
+
+vector float vec_re (vector float);
+
+vector signed char vec_rl (vector signed char, vector unsigned char);
+vector unsigned char vec_rl (vector unsigned char, vector unsigned char);
+vector signed short vec_rl (vector signed short, vector unsigned short);
+
+vector unsigned short vec_rl (vector unsigned short, vector unsigned short);
+vector signed int vec_rl (vector signed int, vector unsigned int);
+vector unsigned int vec_rl (vector unsigned int, vector unsigned int);
+
+vector float vec_round (vector float);
+
+vector float vec_rsqrte (vector float);
+
+vector float vec_sel (vector float, vector float, vector signed int);
+vector float vec_sel (vector float, vector float, vector unsigned int);
+vector signed int vec_sel (vector signed int, vector signed int, vector signed int);
+vector signed int vec_sel (vector signed int, vector signed int, vector unsigned int);
+vector unsigned int vec_sel (vector unsigned int, vector unsigned int, vector signed int);
+vector unsigned int vec_sel (vector unsigned int, vector unsigned int, vector unsigned int);
+vector signed short vec_sel (vector signed short, vector signed short, vector signed short);
+vector signed short vec_sel (vector signed short, vector signed short, vector unsigned short);
+vector unsigned short vec_sel (vector unsigned short, vector unsigned short, vector signed short);
+vector unsigned short vec_sel (vector unsigned short, vector unsigned short, vector unsigned short);
+vector signed char vec_sel (vector signed char, vector signed char, vector signed char);
+vector signed char vec_sel (vector signed char, vector signed char, vector unsigned char);
+vector unsigned char vec_sel (vector unsigned char, vector unsigned char, vector signed char);
+vector unsigned char vec_sel (vector unsigned char, vector unsigned char, vector unsigned char);
+
+vector signed char vec_sl (vector signed char, vector unsigned char);
+vector unsigned char vec_sl (vector unsigned char, vector unsigned char);
+vector signed short vec_sl (vector signed short, vector unsigned short);
+
+vector unsigned short vec_sl (vector unsigned short, vector unsigned short);
+vector signed int vec_sl (vector signed int, vector unsigned int);
+vector unsigned int vec_sl (vector unsigned int, vector unsigned int);
+
+vector float vec_sld (vector float, vector float, const char);
+vector signed int vec_sld (vector signed int, vector signed int, const char);
+vector unsigned int vec_sld (vector unsigned int, vector unsigned int, const char);
+vector signed short vec_sld (vector signed short, vector signed short, const char);
+vector unsigned short vec_sld (vector unsigned short, vector unsigned short, const char);
+vector signed char vec_sld (vector signed char, vector signed char, const char);
+vector unsigned char vec_sld (vector unsigned char, vector unsigned char, const char);
+
+vector signed int vec_sll (vector signed int, vector unsigned int);
+vector signed int vec_sll (vector signed int, vector unsigned short);
+vector signed int vec_sll (vector signed int, vector unsigned char);
+vector unsigned int vec_sll (vector unsigned int, vector unsigned int);
+vector unsigned int vec_sll (vector unsigned int, vector unsigned short);
+vector unsigned int vec_sll (vector unsigned int, vector unsigned char);
+
+vector signed short vec_sll (vector signed short, vector unsigned int);
+vector signed short vec_sll (vector signed short, vector unsigned short);
+vector signed short vec_sll (vector signed short, vector unsigned char);
+
+vector unsigned short vec_sll (vector unsigned short, vector unsigned int);
+vector unsigned short vec_sll (vector unsigned short, vector unsigned short);
+vector unsigned short vec_sll (vector unsigned short, vector unsigned char);
+vector signed char vec_sll (vector signed char, vector unsigned int);
+vector signed char vec_sll (vector signed char, vector unsigned short);
+vector signed char vec_sll (vector signed char, vector unsigned char);
+vector unsigned char vec_sll (vector unsigned char, vector unsigned int);
+vector unsigned char vec_sll (vector unsigned char, vector unsigned short);
+vector unsigned char vec_sll (vector unsigned char, vector unsigned char);
+
+vector float vec_slo (vector float, vector signed char);
+vector float vec_slo (vector float, vector unsigned char);
+vector signed int vec_slo (vector signed int, vector signed char);
+vector signed int vec_slo (vector signed int, vector unsigned char);
+vector unsigned int vec_slo (vector unsigned int, vector signed char);
+vector unsigned int vec_slo (vector unsigned int, vector unsigned char);
+
+vector signed short vec_slo (vector signed short, vector signed char);
+vector signed short vec_slo (vector signed short, vector unsigned char);
+
+vector unsigned short vec_slo (vector unsigned short, vector signed char);
+vector unsigned short vec_slo (vector unsigned short, vector unsigned char);
+vector signed char vec_slo (vector signed char, vector signed char);
+vector signed char vec_slo (vector signed char, vector unsigned char);
+vector unsigned char vec_slo (vector unsigned char, vector signed char);
+
+vector unsigned char vec_slo (vector unsigned char, vector unsigned char);
+
+vector signed char vec_splat (vector signed char, const char);
+vector unsigned char vec_splat (vector unsigned char, const char);
+vector signed short vec_splat (vector signed short, const char);
+vector unsigned short vec_splat (vector unsigned short, const char);
+vector float vec_splat (vector float, const char);
+vector signed int vec_splat (vector signed int, const char);
+vector unsigned int vec_splat (vector unsigned int, const char);
+
+vector signed char vec_splat_s8 (const char);
+
+vector signed short vec_splat_s16 (const char);
+
+vector signed int vec_splat_s32 (const char);
+
+vector unsigned char vec_splat_u8 (const char);
+
+vector unsigned short vec_splat_u16 (const char);
+
+vector unsigned int vec_splat_u32 (const char);
+
+vector signed char vec_sr (vector signed char, vector unsigned char);
+vector unsigned char vec_sr (vector unsigned char, vector unsigned char);
+vector signed short vec_sr (vector signed short, vector unsigned short);
+
+vector unsigned short vec_sr (vector unsigned short, vector unsigned short);
+vector signed int vec_sr (vector signed int, vector unsigned int);
+vector unsigned int vec_sr (vector unsigned int, vector unsigned int);
+
+vector signed char vec_sra (vector signed char, vector unsigned char);
+vector unsigned char vec_sra (vector unsigned char, vector unsigned char);
+vector signed short vec_sra (vector signed short, vector unsigned short);
+vector unsigned short vec_sra (vector unsigned short, vector unsigned short);
+vector signed int vec_sra (vector signed int, vector unsigned int);
+vector unsigned int vec_sra (vector unsigned int, vector unsigned int);
+
+vector signed int vec_srl (vector signed int, vector unsigned int);
+vector signed int vec_srl (vector signed int, vector unsigned short);
+vector signed int vec_srl (vector signed int, vector unsigned char);
+vector unsigned int vec_srl (vector unsigned int, vector unsigned int);
+vector unsigned int vec_srl (vector unsigned int, vector unsigned short);
+vector unsigned int vec_srl (vector unsigned int, vector unsigned char);
+
+vector signed short vec_srl (vector signed short, vector unsigned int);
+vector signed short vec_srl (vector signed short, vector unsigned short);
+vector signed short vec_srl (vector signed short, vector unsigned char);
+
+vector unsigned short vec_srl (vector unsigned short, vector unsigned int);
+vector unsigned short vec_srl (vector unsigned short, vector unsigned short);
+vector unsigned short vec_srl (vector unsigned short, vector unsigned char);
+vector signed char vec_srl (vector signed char, vector unsigned int);
+vector signed char vec_srl (vector signed char, vector unsigned short);
+vector signed char vec_srl (vector signed char, vector unsigned char);
+vector unsigned char vec_srl (vector unsigned char, vector unsigned int);
+vector unsigned char vec_srl (vector unsigned char, vector unsigned short);
+vector unsigned char vec_srl (vector unsigned char, vector unsigned char);
+
+vector float vec_sro (vector float, vector signed char);
+vector float vec_sro (vector float, vector unsigned char);
+vector signed int vec_sro (vector signed int, vector signed char);
+vector signed int vec_sro (vector signed int, vector unsigned char);
+vector unsigned int vec_sro (vector unsigned int, vector signed char);
+vector unsigned int vec_sro (vector unsigned int, vector unsigned char);
+
+vector signed short vec_sro (vector signed short, vector signed char);
+vector signed short vec_sro (vector signed short, vector unsigned char);
+
+vector unsigned short vec_sro (vector unsigned short, vector signed char);
+vector unsigned short vec_sro (vector unsigned short, vector unsigned char);
+vector signed char vec_sro (vector signed char, vector signed char);
+vector signed char vec_sro (vector signed char, vector unsigned char);
+vector unsigned char vec_sro (vector unsigned char, vector signed char);
+
+vector unsigned char vec_sro (vector unsigned char, vector unsigned char);
+
+void vec_st (vector float, int, float *);
+void vec_st (vector float, int, vector float *);
+void vec_st (vector signed int, int, int *);
+void vec_st (vector signed int, int, unsigned int *);
+void vec_st (vector unsigned int, int, unsigned int *);
+void vec_st (vector unsigned int, int, vector unsigned int *);
+void vec_st (vector signed short, int, short *);
+void vec_st (vector signed short, int, vector unsigned short *);
+void vec_st (vector signed short, int, vector signed short *);
+void vec_st (vector unsigned short, int, unsigned short *);
+void vec_st (vector unsigned short, int, vector unsigned short *);
+void vec_st (vector signed char, int, signed char *);
+void vec_st (vector signed char, int, unsigned char *);
+void vec_st (vector signed char, int, vector signed char *);
+void vec_st (vector unsigned char, int, unsigned char *);
+void vec_st (vector unsigned char, int, vector unsigned char *);
+
+void vec_ste (vector signed char, int, unsigned char *);
+void vec_ste (vector signed char, int, signed char *);
+void vec_ste (vector unsigned char, int, unsigned char *);
+void vec_ste (vector signed short, int, short *);
+void vec_ste (vector signed short, int, unsigned short *);
+void vec_ste (vector unsigned short, int, void *);
+void vec_ste (vector signed int, int, unsigned int *);
+void vec_ste (vector signed int, int, int *);
+void vec_ste (vector unsigned int, int, unsigned int *);
+void vec_ste (vector float, int, float *);
+
+void vec_stl (vector float, int, vector float *);
+void vec_stl (vector float, int, float *);
+void vec_stl (vector signed int, int, vector signed int *);
+void vec_stl (vector signed int, int, int *);
+void vec_stl (vector signed int, int, unsigned int *);
+void vec_stl (vector unsigned int, int, vector unsigned int *);
+void vec_stl (vector unsigned int, int, unsigned int *);
+void vec_stl (vector signed short, int, short *);
+void vec_stl (vector signed short, int, unsigned short *);
+void vec_stl (vector signed short, int, vector signed short *);
+void vec_stl (vector unsigned short, int, unsigned short *);
+void vec_stl (vector unsigned short, int, vector signed short *);
+void vec_stl (vector signed char, int, signed char *);
+void vec_stl (vector signed char, int, unsigned char *);
+void vec_stl (vector signed char, int, vector signed char *);
+void vec_stl (vector unsigned char, int, unsigned char *);
+void vec_stl (vector unsigned char, int, vector unsigned char *);
+
+vector signed char vec_sub (vector signed char, vector signed char);
+vector unsigned char vec_sub (vector signed char, vector unsigned char);
+
+vector unsigned char vec_sub (vector unsigned char, vector signed char);
+
+vector unsigned char vec_sub (vector unsigned char, vector unsigned char);
+vector signed short vec_sub (vector signed short, vector signed short);
+vector unsigned short vec_sub (vector signed short, vector unsigned short);
+vector unsigned short vec_sub (vector unsigned short, vector signed short);
+vector unsigned short vec_sub (vector unsigned short, vector unsigned short);
+vector signed int vec_sub (vector signed int, vector signed int);
+vector unsigned int vec_sub (vector signed int, vector unsigned int);
+vector unsigned int vec_sub (vector unsigned int, vector signed int);
+vector unsigned int vec_sub (vector unsigned int, vector unsigned int);
+vector float vec_sub (vector float, vector float);
+
+vector unsigned int vec_subc (vector unsigned int, vector unsigned int);
+
+vector unsigned char vec_subs (vector signed char, vector unsigned char);
+vector unsigned char vec_subs (vector unsigned char, vector signed char);
+vector unsigned char vec_subs (vector unsigned char, vector unsigned char);
+vector signed char vec_subs (vector signed char, vector signed char);
+vector unsigned short vec_subs (vector signed short, vector unsigned short);
+vector unsigned short vec_subs (vector unsigned short, vector signed short);
+vector unsigned short vec_subs (vector unsigned short, vector unsigned short);
+vector signed short vec_subs (vector signed short, vector signed short);
+
+vector unsigned int vec_subs (vector signed int, vector unsigned int);
+vector unsigned int vec_subs (vector unsigned int, vector signed int);
+vector unsigned int vec_subs (vector unsigned int, vector unsigned int);
+
+vector signed int vec_subs (vector signed int, vector signed int);
+
+vector unsigned int vec_sum4s (vector unsigned char, vector unsigned int);
+vector signed int vec_sum4s (vector signed char, vector signed int);
+vector signed int vec_sum4s (vector signed short, vector signed int);
+
+vector signed int vec_sum2s (vector signed int, vector signed int);
+
+vector signed int vec_sums (vector signed int, vector signed int);
+
+vector float vec_trunc (vector float);
+
+vector signed short vec_unpackh (vector signed char);
+vector unsigned int vec_unpackh (vector signed short);
+vector signed int vec_unpackh (vector signed short);
+
+vector signed short vec_unpackl (vector signed char);
+vector unsigned int vec_unpackl (vector signed short);
+vector signed int vec_unpackl (vector signed short);
+
+vector float vec_xor (vector float, vector float);
+vector float vec_xor (vector float, vector signed int);
+vector float vec_xor (vector signed int, vector float);
+vector signed int vec_xor (vector signed int, vector signed int);
+vector unsigned int vec_xor (vector signed int, vector unsigned int);
+vector unsigned int vec_xor (vector unsigned int, vector signed int);
+vector unsigned int vec_xor (vector unsigned int, vector unsigned int);
+vector signed short vec_xor (vector signed short, vector signed short);
+vector unsigned short vec_xor (vector signed short, vector unsigned short);
+vector unsigned short vec_xor (vector unsigned short, vector signed short);
+vector unsigned short vec_xor (vector unsigned short, vector unsigned short);
+vector signed char vec_xor (vector signed char, vector signed char);
+vector unsigned char vec_xor (vector signed char, vector unsigned char);
+
+vector unsigned char vec_xor (vector unsigned char, vector signed char);
+
+vector unsigned char vec_xor (vector unsigned char, vector unsigned char);
+
+vector signed int vec_all_eq (vector signed char, vector unsigned char);
+
+vector signed int vec_all_eq (vector signed char, vector signed char);
+vector signed int vec_all_eq (vector unsigned char, vector signed char);
+
+vector signed int vec_all_eq (vector unsigned char, vector unsigned char);
+vector signed int vec_all_eq (vector signed short, vector unsigned short);
+vector signed int vec_all_eq (vector signed short, vector signed short);
+
+vector signed int vec_all_eq (vector unsigned short, vector signed short);
+vector signed int vec_all_eq (vector unsigned short, vector unsigned short);
+vector signed int vec_all_eq (vector signed int, vector unsigned int);
+vector signed int vec_all_eq (vector signed int, vector signed int);
+vector signed int vec_all_eq (vector unsigned int, vector signed int);
+vector signed int vec_all_eq (vector unsigned int, vector unsigned int);
+
+vector signed int vec_all_eq (vector float, vector float);
+
+vector signed int vec_all_ge (vector signed char, vector unsigned char);
+
+vector signed int vec_all_ge (vector unsigned char, vector signed char);
+
+vector signed int vec_all_ge (vector unsigned char, vector unsigned char);
+vector signed int vec_all_ge (vector signed char, vector signed char);
+vector signed int vec_all_ge (vector signed short, vector unsigned short);
+vector signed int vec_all_ge (vector unsigned short, vector signed short);
+vector signed int vec_all_ge (vector unsigned short, vector unsigned short);
+vector signed int vec_all_ge (vector signed short, vector signed short);
+
+vector signed int vec_all_ge (vector signed int, vector unsigned int);
+vector signed int vec_all_ge (vector unsigned int, vector signed int);
+vector signed int vec_all_ge (vector unsigned int, vector unsigned int);
+
+vector signed int vec_all_ge (vector signed int, vector signed int);
+vector signed int vec_all_ge (vector float, vector float);
+
+vector signed int vec_all_gt (vector signed char, vector unsigned char);
+
+vector signed int vec_all_gt (vector unsigned char, vector signed char);
+
+vector signed int vec_all_gt (vector unsigned char, vector unsigned char);
+vector signed int vec_all_gt (vector signed char, vector signed char);
+vector signed int vec_all_gt (vector signed short, vector unsigned short);
+vector signed int vec_all_gt (vector unsigned short, vector signed short);
+vector signed int vec_all_gt (vector unsigned short, vector unsigned short);
+vector signed int vec_all_gt (vector signed short, vector signed short);
+
+vector signed int vec_all_gt (vector signed int, vector unsigned int);
+vector signed int vec_all_gt (vector unsigned int, vector signed int);
+vector signed int vec_all_gt (vector unsigned int, vector unsigned int);
+
+vector signed int vec_all_gt (vector signed int, vector signed int);
+vector signed int vec_all_gt (vector float, vector float);
+
+vector signed int vec_all_in (vector float, vector float);
+
+vector signed int vec_all_le (vector signed char, vector unsigned char);
+
+vector signed int vec_all_le (vector unsigned char, vector signed char);
+
+vector signed int vec_all_le (vector unsigned char, vector unsigned char);
+vector signed int vec_all_le (vector signed char, vector signed char);
+vector signed int vec_all_le (vector signed short, vector unsigned short);
+vector signed int vec_all_le (vector unsigned short, vector signed short);
+vector signed int vec_all_le (vector unsigned short, vector unsigned short);
+vector signed int vec_all_le (vector signed short, vector signed short);
+
+vector signed int vec_all_le (vector signed int, vector unsigned int);
+vector signed int vec_all_le (vector unsigned int, vector signed int);
+vector signed int vec_all_le (vector unsigned int, vector unsigned int);
+
+vector signed int vec_all_le (vector signed int, vector signed int);
+vector signed int vec_all_le (vector float, vector float);
+
+vector signed int vec_all_lt (vector signed char, vector unsigned char);
+
+vector signed int vec_all_lt (vector unsigned char, vector signed char);
+
+vector signed int vec_all_lt (vector unsigned char, vector unsigned char);
+vector signed int vec_all_lt (vector signed char, vector signed char);
+vector signed int vec_all_lt (vector signed short, vector unsigned short);
+vector signed int vec_all_lt (vector unsigned short, vector signed short);
+vector signed int vec_all_lt (vector unsigned short, vector unsigned short);
+vector signed int vec_all_lt (vector signed short, vector signed short);
+
+vector signed int vec_all_lt (vector signed int, vector unsigned int);
+vector signed int vec_all_lt (vector unsigned int, vector signed int);
+vector signed int vec_all_lt (vector unsigned int, vector unsigned int);
+
+vector signed int vec_all_lt (vector signed int, vector signed int);
+vector signed int vec_all_lt (vector float, vector float);
+
+vector signed int vec_all_nan (vector float);
+
+vector signed int vec_all_ne (vector signed char, vector unsigned char);
+
+vector signed int vec_all_ne (vector signed char, vector signed char);
+vector signed int vec_all_ne (vector unsigned char, vector signed char);
+
+vector signed int vec_all_ne (vector unsigned char, vector unsigned char);
+vector signed int vec_all_ne (vector signed short, vector unsigned short);
+vector signed int vec_all_ne (vector signed short, vector signed short);
+
+vector signed int vec_all_ne (vector unsigned short, vector signed short);
+vector signed int vec_all_ne (vector unsigned short, vector unsigned short);
+vector signed int vec_all_ne (vector signed int, vector unsigned int);
+vector signed int vec_all_ne (vector signed int, vector signed int);
+vector signed int vec_all_ne (vector unsigned int, vector signed int);
+vector signed int vec_all_ne (vector unsigned int, vector unsigned int);
+
+vector signed int vec_all_ne (vector float, vector float);
+
+vector signed int vec_all_nge (vector float, vector float);
+
+vector signed int vec_all_ngt (vector float, vector float);
+
+vector signed int vec_all_nle (vector float, vector float);
+
+vector signed int vec_all_nlt (vector float, vector float);
+
+vector signed int vec_all_numeric (vector float);
+
+vector signed int vec_any_eq (vector signed char, vector unsigned char);
+
+vector signed int vec_any_eq (vector signed char, vector signed char);
+vector signed int vec_any_eq (vector unsigned char, vector signed char);
+
+vector signed int vec_any_eq (vector unsigned char, vector unsigned char);
+vector signed int vec_any_eq (vector signed short, vector unsigned short);
+vector signed int vec_any_eq (vector signed short, vector signed short);
+
+vector signed int vec_any_eq (vector unsigned short, vector signed short);
+vector signed int vec_any_eq (vector unsigned short, vector unsigned short);
+vector signed int vec_any_eq (vector signed int, vector unsigned int);
+vector signed int vec_any_eq (vector signed int, vector signed int);
+vector signed int vec_any_eq (vector unsigned int, vector signed int);
+vector signed int vec_any_eq (vector unsigned int, vector unsigned int);
+
+vector signed int vec_any_eq (vector float, vector float);
+
+vector signed int vec_any_ge (vector signed char, vector unsigned char);
+
+vector signed int vec_any_ge (vector unsigned char, vector signed char);
+
+vector signed int vec_any_ge (vector unsigned char, vector unsigned char);
+vector signed int vec_any_ge (vector signed char, vector signed char);
+vector signed int vec_any_ge (vector signed short, vector unsigned short);
+vector signed int vec_any_ge (vector unsigned short, vector signed short);
+vector signed int vec_any_ge (vector unsigned short, vector unsigned short);
+vector signed int vec_any_ge (vector signed short, vector signed short);
+
+vector signed int vec_any_ge (vector signed int, vector unsigned int);
+vector signed int vec_any_ge (vector unsigned int, vector signed int);
+vector signed int vec_any_ge (vector unsigned int, vector unsigned int);
+
+vector signed int vec_any_ge (vector signed int, vector signed int);
+vector signed int vec_any_ge (vector float, vector float);
+
+vector signed int vec_any_gt (vector signed char, vector unsigned char);
+
+vector signed int vec_any_gt (vector unsigned char, vector signed char);
+
+vector signed int vec_any_gt (vector unsigned char, vector unsigned char);
+vector signed int vec_any_gt (vector signed char, vector signed char);
+vector signed int vec_any_gt (vector signed short, vector unsigned short);
+vector signed int vec_any_gt (vector unsigned short, vector signed short);
+vector signed int vec_any_gt (vector unsigned short, vector unsigned short);
+vector signed int vec_any_gt (vector signed short, vector signed short);
+
+vector signed int vec_any_gt (vector signed int, vector unsigned int);
+vector signed int vec_any_gt (vector unsigned int, vector signed int);
+vector signed int vec_any_gt (vector unsigned int, vector unsigned int);
+
+vector signed int vec_any_gt (vector signed int, vector signed int);
+vector signed int vec_any_gt (vector float, vector float);
+
+vector signed int vec_any_le (vector signed char, vector unsigned char);
+
+vector signed int vec_any_le (vector unsigned char, vector signed char);
+
+vector signed int vec_any_le (vector unsigned char, vector unsigned char);
+vector signed int vec_any_le (vector signed char, vector signed char);
+vector signed int vec_any_le (vector signed short, vector unsigned short);
+vector signed int vec_any_le (vector unsigned short, vector signed short);
+vector signed int vec_any_le (vector unsigned short, vector unsigned short);
+vector signed int vec_any_le (vector signed short, vector signed short);
+
+vector signed int vec_any_le (vector signed int, vector unsigned int);
+vector signed int vec_any_le (vector unsigned int, vector signed int);
+vector signed int vec_any_le (vector unsigned int, vector unsigned int);
+
+vector signed int vec_any_le (vector signed int, vector signed int);
+vector signed int vec_any_le (vector float, vector float);
+
+vector signed int vec_any_lt (vector signed char, vector unsigned char);
+
+vector signed int vec_any_lt (vector unsigned char, vector signed char);
+
+vector signed int vec_any_lt (vector unsigned char, vector unsigned char);
+vector signed int vec_any_lt (vector signed char, vector signed char);
+vector signed int vec_any_lt (vector signed short, vector unsigned short);
+vector signed int vec_any_lt (vector unsigned short, vector signed short);
+vector signed int vec_any_lt (vector unsigned short, vector unsigned short);
+vector signed int vec_any_lt (vector signed short, vector signed short);
+
+vector signed int vec_any_lt (vector signed int, vector unsigned int);
+vector signed int vec_any_lt (vector unsigned int, vector signed int);
+vector signed int vec_any_lt (vector unsigned int, vector unsigned int);
+
+vector signed int vec_any_lt (vector signed int, vector signed int);
+vector signed int vec_any_lt (vector float, vector float);
+
+vector signed int vec_any_nan (vector float);
+
+vector signed int vec_any_ne (vector signed char, vector unsigned char);
+
+vector signed int vec_any_ne (vector signed char, vector signed char);
+vector signed int vec_any_ne (vector unsigned char, vector signed char);
+
+vector signed int vec_any_ne (vector unsigned char, vector unsigned char);
+vector signed int vec_any_ne (vector signed short, vector unsigned short);
+vector signed int vec_any_ne (vector signed short, vector signed short);
+
+vector signed int vec_any_ne (vector unsigned short, vector signed short);
+vector signed int vec_any_ne (vector unsigned short, vector unsigned short);
+vector signed int vec_any_ne (vector signed int, vector unsigned int);
+vector signed int vec_any_ne (vector signed int, vector signed int);
+vector signed int vec_any_ne (vector unsigned int, vector signed int);
+vector signed int vec_any_ne (vector unsigned int, vector unsigned int);
+
+vector signed int vec_any_ne (vector float, vector float);
+
+vector signed int vec_any_nge (vector float, vector float);
+
+vector signed int vec_any_ngt (vector float, vector float);
+
+vector signed int vec_any_nle (vector float, vector float);
+
+vector signed int vec_any_nlt (vector float, vector float);
+
+vector signed int vec_any_numeric (vector float);
+
+vector signed int vec_any_out (vector float, vector float);
+@end smallexample
+
+@node Pragmas
+@section Pragmas Accepted by GCC
+@cindex pragmas
+@cindex #pragma
+
+GCC supports several types of pragmas, primarily in order to compile
+code originally written for other compilers.  Note that in general
+we do not recommend the use of pragmas; @xref{Function Attributes},
+for further explanation.
+
+@menu
+* ARM Pragmas::
+* Darwin Pragmas::
+@end menu
+
+@node ARM Pragmas
+@subsection ARM Pragmas
+
+The ARM target defines pragmas for controlling the default addition of
+@code{long_call} and @code{short_call} attributes to functions.
+@xref{Function Attributes}, for information about the effects of these
+attributes.
+
+@table @code
+@item long_calls
+@cindex pragma, long_calls
+Set all subsequent functions to have the @code{long_call} attribute.
+
+@item no_long_calls
+@cindex pragma, no_long_calls
+Set all subsequent functions to have the @code{short_call} attribute.
+
+@item long_calls_off
+@cindex pragma, long_calls_off
+Do not affect the @code{long_call} or @code{short_call} attributes of
+subsequent functions.
+@end table
+
+@c Describe c4x pragmas here.
+@c Describe h8300 pragmas here.
+@c Describe i370 pragmas here.
+@c Describe i960 pragmas here.
+@c Describe sh pragmas here.
+@c Describe v850 pragmas here.
+
+@node Darwin Pragmas
+@subsection Darwin Pragmas
+
+The following pragmas are available for all architectures running the
+Darwin operating system.  These are useful for compatibility with other
+MacOS compilers.
+
+@table @code
+@item mark @var{tokens}@dots{}
+@cindex pragma, mark
+This pragma is accepted, but has no effect.
+
+@item options align=@var{alignment}
+@cindex pragma, options align
+This pragma sets the alignment of fields in structures.  The values of
+@var{alignment} may be @code{mac68k}, to emulate m68k alignment, or
+@code{power}, to emulate PowerPC alignment.  Uses of this pragma nest
+properly; to restore the previous setting, use @code{reset} for the
+@var{alignment}.
+
+@item segment @var{tokens}@dots{}
+@cindex pragma, segment
+This pragma is accepted, but has no effect.
+
+@item unused (@var{var} [, @var{var}]@dots{})
+@cindex pragma, unused
+This pragma declares variables to be possibly unused.  GCC will not
+produce warnings for the listed variables.  The effect is similar to
+that of the @code{unused} attribute, except that this pragma may appear
+anywhere within the variables' scopes.
+@end table
+
+@node Unnamed Fields
+@section Unnamed struct/union fields within structs/unions.
+@cindex struct
+@cindex union
+
+For compatibility with other compilers, GCC allows you to define
+a structure or union that contains, as fields, structures and unions
+without names.  For example:
+
+@example
+struct @{
+  int a;
+  union @{
+    int b;
+    float c;
+  @};
+  int d;
+@} foo;
+@end example
+
+In this example, the user would be able to access members of the unnamed
+union with code like @samp{foo.b}.  Note that only unnamed structs and
+unions are allowed, you may not have, for example, an unnamed
+@code{int}.
+
+You must never create such structures that cause ambiguous field definitions.
+For example, this structure:
+
+@example
+struct @{
+  int a;
+  struct @{
+    int a;
+  @};
+@} foo;
+@end example
+
+It is ambiguous which @code{a} is being referred to with @samp{foo.a}.
+Such constructs are not supported and must be avoided.  In the future,
+such constructs may be detected and treated as compilation errors.
+
+@node C++ Extensions
+@chapter Extensions to the C++ Language
+@cindex extensions, C++ language
+@cindex C++ language extensions
+
+The GNU compiler provides these extensions to the C++ language (and you
+can also use most of the C language extensions in your C++ programs).  If you
+want to write code that checks whether these features are available, you can
+test for the GNU compiler the same way as for C programs: check for a
+predefined macro @code{__GNUC__}.  You can also use @code{__GNUG__} to
+test specifically for GNU C++ (@pxref{Standard Predefined,,Standard
+Predefined Macros,cpp.info,The C Preprocessor}).
+
+@menu
+* Min and Max::		C++ Minimum and maximum operators.
+* Volatiles::		What constitutes an access to a volatile object.
+* Restricted Pointers:: C99 restricted pointers and references.
+* Vague Linkage::       Where G++ puts inlines, vtables and such.
+* C++ Interface::       You can use a single C++ header file for both
+                        declarations and definitions.
+* Template Instantiation:: Methods for ensuring that exactly one copy of
+                        each needed template instantiation is emitted.
+* Bound member functions:: You can extract a function pointer to the
+                        method denoted by a @samp{->*} or @samp{.*} expression.
+* C++ Attributes::      Variable, function, and type attributes for C++ only.
+* Java Exceptions::     Tweaking exception handling to work with Java.
+* Deprecated Features:: Things might disappear from g++.
+* Backwards Compatibility:: Compatibilities with earlier definitions of C++.
+@end menu
+
+@node Min and Max
+@section Minimum and Maximum Operators in C++
+
+It is very convenient to have operators which return the ``minimum'' or the
+``maximum'' of two arguments.  In GNU C++ (but not in GNU C),
+
+@table @code
+@item @var{a} <? @var{b}
+@findex <?
+@cindex minimum operator
+is the @dfn{minimum}, returning the smaller of the numeric values
+@var{a} and @var{b};
+
+@item @var{a} >? @var{b}
+@findex >?
+@cindex maximum operator
+is the @dfn{maximum}, returning the larger of the numeric values @var{a}
+and @var{b}.
+@end table
+
+These operations are not primitive in ordinary C++, since you can
+use a macro to return the minimum of two things in C++, as in the
+following example.
+
+@example
+#define MIN(X,Y) ((X) < (Y) ? : (X) : (Y))
+@end example
+
+@noindent
+You might then use @w{@samp{int min = MIN (i, j);}} to set @var{min} to
+the minimum value of variables @var{i} and @var{j}.
+
+However, side effects in @code{X} or @code{Y} may cause unintended
+behavior.  For example, @code{MIN (i++, j++)} will fail, incrementing
+the smaller counter twice.  A GNU C extension allows you to write safe
+macros that avoid this kind of problem (@pxref{Naming Types,,Naming an
+Expression's Type}).  However, writing @code{MIN} and @code{MAX} as
+macros also forces you to use function-call notation for a
+fundamental arithmetic operation.  Using GNU C++ extensions, you can
+write @w{@samp{int min = i <? j;}} instead.
+
+Since @code{<?} and @code{>?} are built into the compiler, they properly
+handle expressions with side-effects;  @w{@samp{int min = i++ <? j++;}}
+works correctly.
+
+@node Volatiles
+@section When is a Volatile Object Accessed?
+@cindex accessing volatiles
+@cindex volatile read
+@cindex volatile write
+@cindex volatile access
+
+Both the C and C++ standard have the concept of volatile objects.  These
+are normally accessed by pointers and used for accessing hardware.  The
+standards encourage compilers to refrain from optimizations
+concerning accesses to volatile objects that it might perform on
+non-volatile objects.  The C standard leaves it implementation defined
+as to what constitutes a volatile access.  The C++ standard omits to
+specify this, except to say that C++ should behave in a similar manner
+to C with respect to volatiles, where possible.  The minimum either
+standard specifies is that at a sequence point all previous accesses to
+volatile objects have stabilized and no subsequent accesses have
+occurred.  Thus an implementation is free to reorder and combine
+volatile accesses which occur between sequence points, but cannot do so
+for accesses across a sequence point.  The use of volatiles does not
+allow you to violate the restriction on updating objects multiple times
+within a sequence point.
+
+In most expressions, it is intuitively obvious what is a read and what is
+a write.  For instance
+
+@example
+volatile int *dst = @var{somevalue};
+volatile int *src = @var{someothervalue};
+*dst = *src;
+@end example
+
+@noindent
+will cause a read of the volatile object pointed to by @var{src} and stores the
+value into the volatile object pointed to by @var{dst}.  There is no
+guarantee that these reads and writes are atomic, especially for objects
+larger than @code{int}.
+
+Less obvious expressions are where something which looks like an access
+is used in a void context.  An example would be,
+
+@example
+volatile int *src = @var{somevalue};
+*src;
+@end example
+
+With C, such expressions are rvalues, and as rvalues cause a read of
+the object, GCC interprets this as a read of the volatile being pointed
+to.  The C++ standard specifies that such expressions do not undergo
+lvalue to rvalue conversion, and that the type of the dereferenced
+object may be incomplete.  The C++ standard does not specify explicitly
+that it is this lvalue to rvalue conversion which is responsible for
+causing an access.  However, there is reason to believe that it is,
+because otherwise certain simple expressions become undefined.  However,
+because it would surprise most programmers, G++ treats dereferencing a
+pointer to volatile object of complete type in a void context as a read
+of the object.  When the object has incomplete type, G++ issues a
+warning.
+
+@example
+struct S;
+struct T @{int m;@};
+volatile S *ptr1 = @var{somevalue};
+volatile T *ptr2 = @var{somevalue};
+*ptr1;
+*ptr2;
+@end example
+
+In this example, a warning is issued for @code{*ptr1}, and @code{*ptr2}
+causes a read of the object pointed to.  If you wish to force an error on
+the first case, you must force a conversion to rvalue with, for instance
+a static cast, @code{static_cast<S>(*ptr1)}.
+
+When using a reference to volatile, G++ does not treat equivalent
+expressions as accesses to volatiles, but instead issues a warning that
+no volatile is accessed.  The rationale for this is that otherwise it
+becomes difficult to determine where volatile access occur, and not
+possible to ignore the return value from functions returning volatile
+references.  Again, if you wish to force a read, cast the reference to
+an rvalue.
+
+@node Restricted Pointers
+@section Restricting Pointer Aliasing
+@cindex restricted pointers
+@cindex restricted references
+@cindex restricted this pointer
+
+As with gcc, g++ understands the C99 feature of restricted pointers,
+specified with the @code{__restrict__}, or @code{__restrict} type
+qualifier.  Because you cannot compile C++ by specifying the @option{-std=c99}
+language flag, @code{restrict} is not a keyword in C++.
+
+In addition to allowing restricted pointers, you can specify restricted
+references, which indicate that the reference is not aliased in the local
+context.
+
+@example
+void fn (int *__restrict__ rptr, int &__restrict__ rref)
+@{
+  @dots{}
+@}
+@end example
+
+@noindent
+In the body of @code{fn}, @var{rptr} points to an unaliased integer and
+@var{rref} refers to a (different) unaliased integer.
+
+You may also specify whether a member function's @var{this} pointer is
+unaliased by using @code{__restrict__} as a member function qualifier.
+
+@example
+void T::fn () __restrict__
+@{
+  @dots{}
+@}
+@end example
+
+@noindent
+Within the body of @code{T::fn}, @var{this} will have the effective
+definition @code{T *__restrict__ const this}.  Notice that the
+interpretation of a @code{__restrict__} member function qualifier is
+different to that of @code{const} or @code{volatile} qualifier, in that it
+is applied to the pointer rather than the object.  This is consistent with
+other compilers which implement restricted pointers.
+
+As with all outermost parameter qualifiers, @code{__restrict__} is
+ignored in function definition matching.  This means you only need to
+specify @code{__restrict__} in a function definition, rather than
+in a function prototype as well.
+
+@node Vague Linkage
+@section Vague Linkage
+@cindex vague linkage
+
+There are several constructs in C++ which require space in the object
+file but are not clearly tied to a single translation unit.  We say that
+these constructs have ``vague linkage''.  Typically such constructs are
+emitted wherever they are needed, though sometimes we can be more
+clever.
+
+@table @asis
+@item Inline Functions
+Inline functions are typically defined in a header file which can be
+included in many different compilations.  Hopefully they can usually be
+inlined, but sometimes an out-of-line copy is necessary, if the address
+of the function is taken or if inlining fails.  In general, we emit an
+out-of-line copy in all translation units where one is needed.  As an
+exception, we only emit inline virtual functions with the vtable, since
+it will always require a copy.
+
+Local static variables and string constants used in an inline function
+are also considered to have vague linkage, since they must be shared
+between all inlined and out-of-line instances of the function.
+
+@item VTables
+@cindex vtable
+C++ virtual functions are implemented in most compilers using a lookup
+table, known as a vtable.  The vtable contains pointers to the virtual
+functions provided by a class, and each object of the class contains a
+pointer to its vtable (or vtables, in some multiple-inheritance
+situations).  If the class declares any non-inline, non-pure virtual
+functions, the first one is chosen as the ``key method'' for the class,
+and the vtable is only emitted in the translation unit where the key
+method is defined.
+
+@emph{Note:} If the chosen key method is later defined as inline, the
+vtable will still be emitted in every translation unit which defines it.
+Make sure that any inline virtuals are declared inline in the class
+body, even if they are not defined there.
+
+@item type_info objects
+@cindex type_info
+@cindex RTTI
+C++ requires information about types to be written out in order to
+implement @samp{dynamic_cast}, @samp{typeid} and exception handling.
+For polymorphic classes (classes with virtual functions), the type_info
+object is written out along with the vtable so that @samp{dynamic_cast}
+can determine the dynamic type of a class object at runtime.  For all
+other types, we write out the type_info object when it is used: when
+applying @samp{typeid} to an expression, throwing an object, or
+referring to a type in a catch clause or exception specification.
+
+@item Template Instantiations
+Most everything in this section also applies to template instantiations,
+but there are other options as well.
+@xref{Template Instantiation,,Where's the Template?}.
+
+@end table
+
+When used with GNU ld version 2.8 or later on an ELF system such as
+Linux/GNU or Solaris 2, or on Microsoft Windows, duplicate copies of
+these constructs will be discarded at link time.  This is known as
+COMDAT support.
+
+On targets that don't support COMDAT, but do support weak symbols, GCC
+will use them.  This way one copy will override all the others, but
+the unused copies will still take up space in the executable.
+
+For targets which do not support either COMDAT or weak symbols,
+most entities with vague linkage will be emitted as local symbols to
+avoid duplicate definition errors from the linker.  This will not happen
+for local statics in inlines, however, as having multiple copies will
+almost certainly break things.
+
+@xref{C++ Interface,,Declarations and Definitions in One Header}, for
+another way to control placement of these constructs.
+
+@node C++ Interface
+@section Declarations and Definitions in One Header
+
+@cindex interface and implementation headers, C++
+@cindex C++ interface and implementation headers
+C++ object definitions can be quite complex.  In principle, your source
+code will need two kinds of things for each object that you use across
+more than one source file.  First, you need an @dfn{interface}
+specification, describing its structure with type declarations and
+function prototypes.  Second, you need the @dfn{implementation} itself.
+It can be tedious to maintain a separate interface description in a
+header file, in parallel to the actual implementation.  It is also
+dangerous, since separate interface and implementation definitions may
+not remain parallel.
+
+@cindex pragmas, interface and implementation
+With GNU C++, you can use a single header file for both purposes.
+
+@quotation
+@emph{Warning:} The mechanism to specify this is in transition.  For the
+nonce, you must use one of two @code{#pragma} commands; in a future
+release of GNU C++, an alternative mechanism will make these
+@code{#pragma} commands unnecessary.
+@end quotation
+
+The header file contains the full definitions, but is marked with
+@samp{#pragma interface} in the source code.  This allows the compiler
+to use the header file only as an interface specification when ordinary
+source files incorporate it with @code{#include}.  In the single source
+file where the full implementation belongs, you can use either a naming
+convention or @samp{#pragma implementation} to indicate this alternate
+use of the header file.
+
+@table @code
+@item #pragma interface
+@itemx #pragma interface "@var{subdir}/@var{objects}.h"
+@kindex #pragma interface
+Use this directive in @emph{header files} that define object classes, to save
+space in most of the object files that use those classes.  Normally,
+local copies of certain information (backup copies of inline member
+functions, debugging information, and the internal tables that implement
+virtual functions) must be kept in each object file that includes class
+definitions.  You can use this pragma to avoid such duplication.  When a
+header file containing @samp{#pragma interface} is included in a
+compilation, this auxiliary information will not be generated (unless
+the main input source file itself uses @samp{#pragma implementation}).
+Instead, the object files will contain references to be resolved at link
+time.
+
+The second form of this directive is useful for the case where you have
+multiple headers with the same name in different directories.  If you
+use this form, you must specify the same string to @samp{#pragma
+implementation}.
+
+@item #pragma implementation
+@itemx #pragma implementation "@var{objects}.h"
+@kindex #pragma implementation
+Use this pragma in a @emph{main input file}, when you want full output from
+included header files to be generated (and made globally visible).  The
+included header file, in turn, should use @samp{#pragma interface}.
+Backup copies of inline member functions, debugging information, and the
+internal tables used to implement virtual functions are all generated in
+implementation files.
+
+@cindex implied @code{#pragma implementation}
+@cindex @code{#pragma implementation}, implied
+@cindex naming convention, implementation headers
+If you use @samp{#pragma implementation} with no argument, it applies to
+an include file with the same basename@footnote{A file's @dfn{basename}
+was the name stripped of all leading path information and of trailing
+suffixes, such as @samp{.h} or @samp{.C} or @samp{.cc}.} as your source
+file.  For example, in @file{allclass.cc}, giving just
+@samp{#pragma implementation}
+by itself is equivalent to @samp{#pragma implementation "allclass.h"}.
+
+In versions of GNU C++ prior to 2.6.0 @file{allclass.h} was treated as
+an implementation file whenever you would include it from
+@file{allclass.cc} even if you never specified @samp{#pragma
+implementation}.  This was deemed to be more trouble than it was worth,
+however, and disabled.
+
+If you use an explicit @samp{#pragma implementation}, it must appear in
+your source file @emph{before} you include the affected header files.
+
+Use the string argument if you want a single implementation file to
+include code from multiple header files.  (You must also use
+@samp{#include} to include the header file; @samp{#pragma
+implementation} only specifies how to use the file---it doesn't actually
+include it.)
+
+There is no way to split up the contents of a single header file into
+multiple implementation files.
+@end table
+
+@cindex inlining and C++ pragmas
+@cindex C++ pragmas, effect on inlining
+@cindex pragmas in C++, effect on inlining
+@samp{#pragma implementation} and @samp{#pragma interface} also have an
+effect on function inlining.
+
+If you define a class in a header file marked with @samp{#pragma
+interface}, the effect on a function defined in that class is similar to
+an explicit @code{extern} declaration---the compiler emits no code at
+all to define an independent version of the function.  Its definition
+is used only for inlining with its callers.
+
+@opindex fno-implement-inlines
+Conversely, when you include the same header file in a main source file
+that declares it as @samp{#pragma implementation}, the compiler emits
+code for the function itself; this defines a version of the function
+that can be found via pointers (or by callers compiled without
+inlining).  If all calls to the function can be inlined, you can avoid
+emitting the function by compiling with @option{-fno-implement-inlines}.
+If any calls were not inlined, you will get linker errors.
+
+@node Template Instantiation
+@section Where's the Template?
+
+@cindex template instantiation
+
+C++ templates are the first language feature to require more
+intelligence from the environment than one usually finds on a UNIX
+system.  Somehow the compiler and linker have to make sure that each
+template instance occurs exactly once in the executable if it is needed,
+and not at all otherwise.  There are two basic approaches to this
+problem, which I will refer to as the Borland model and the Cfront model.
+
+@table @asis
+@item Borland model
+Borland C++ solved the template instantiation problem by adding the code
+equivalent of common blocks to their linker; the compiler emits template
+instances in each translation unit that uses them, and the linker
+collapses them together.  The advantage of this model is that the linker
+only has to consider the object files themselves; there is no external
+complexity to worry about.  This disadvantage is that compilation time
+is increased because the template code is being compiled repeatedly.
+Code written for this model tends to include definitions of all
+templates in the header file, since they must be seen to be
+instantiated.
+
+@item Cfront model
+The AT&T C++ translator, Cfront, solved the template instantiation
+problem by creating the notion of a template repository, an
+automatically maintained place where template instances are stored.  A
+more modern version of the repository works as follows: As individual
+object files are built, the compiler places any template definitions and
+instantiations encountered in the repository.  At link time, the link
+wrapper adds in the objects in the repository and compiles any needed
+instances that were not previously emitted.  The advantages of this
+model are more optimal compilation speed and the ability to use the
+system linker; to implement the Borland model a compiler vendor also
+needs to replace the linker.  The disadvantages are vastly increased
+complexity, and thus potential for error; for some code this can be
+just as transparent, but in practice it can been very difficult to build
+multiple programs in one directory and one program in multiple
+directories.  Code written for this model tends to separate definitions
+of non-inline member templates into a separate file, which should be
+compiled separately.
+@end table
+
+When used with GNU ld version 2.8 or later on an ELF system such as
+Linux/GNU or Solaris 2, or on Microsoft Windows, g++ supports the
+Borland model.  On other systems, g++ implements neither automatic
+model.
+
+A future version of g++ will support a hybrid model whereby the compiler
+will emit any instantiations for which the template definition is
+included in the compile, and store template definitions and
+instantiation context information into the object file for the rest.
+The link wrapper will extract that information as necessary and invoke
+the compiler to produce the remaining instantiations.  The linker will
+then combine duplicate instantiations.
+
+In the mean time, you have the following options for dealing with
+template instantiations:
+
+@enumerate
+@item
+@opindex frepo
+Compile your template-using code with @option{-frepo}.  The compiler will
+generate files with the extension @samp{.rpo} listing all of the
+template instantiations used in the corresponding object files which
+could be instantiated there; the link wrapper, @samp{collect2}, will
+then update the @samp{.rpo} files to tell the compiler where to place
+those instantiations and rebuild any affected object files.  The
+link-time overhead is negligible after the first pass, as the compiler
+will continue to place the instantiations in the same files.
+
+This is your best option for application code written for the Borland
+model, as it will just work.  Code written for the Cfront model will
+need to be modified so that the template definitions are available at
+one or more points of instantiation; usually this is as simple as adding
+@code{#include <tmethods.cc>} to the end of each template header.
+
+For library code, if you want the library to provide all of the template
+instantiations it needs, just try to link all of its object files
+together; the link will fail, but cause the instantiations to be
+generated as a side effect.  Be warned, however, that this may cause
+conflicts if multiple libraries try to provide the same instantiations.
+For greater control, use explicit instantiation as described in the next
+option.
+
+@item
+@opindex fno-implicit-templates
+Compile your code with @option{-fno-implicit-templates} to disable the
+implicit generation of template instances, and explicitly instantiate
+all the ones you use.  This approach requires more knowledge of exactly
+which instances you need than do the others, but it's less
+mysterious and allows greater control.  You can scatter the explicit
+instantiations throughout your program, perhaps putting them in the
+translation units where the instances are used or the translation units
+that define the templates themselves; you can put all of the explicit
+instantiations you need into one big file; or you can create small files
+like
+
+@example
+#include "Foo.h"
+#include "Foo.cc"
+
+template class Foo<int>;
+template ostream& operator <<
+                (ostream&, const Foo<int>&);
+@end example
+
+for each of the instances you need, and create a template instantiation
+library from those.
+
+If you are using Cfront-model code, you can probably get away with not
+using @option{-fno-implicit-templates} when compiling files that don't
+@samp{#include} the member template definitions.
+
+If you use one big file to do the instantiations, you may want to
+compile it without @option{-fno-implicit-templates} so you get all of the
+instances required by your explicit instantiations (but not by any
+other files) without having to specify them as well.
+
+g++ has extended the template instantiation syntax outlined in the
+Working Paper to allow forward declaration of explicit instantiations
+(with @code{extern}), instantiation of the compiler support data for a
+template class (i.e.@: the vtable) without instantiating any of its
+members (with @code{inline}), and instantiation of only the static data
+members of a template class, without the support data or member
+functions (with (@code{static}):
+
+@example
+extern template int max (int, int);
+inline template class Foo<int>;
+static template class Foo<int>;
+@end example
+
+@item
+Do nothing.  Pretend g++ does implement automatic instantiation
+management.  Code written for the Borland model will work fine, but
+each translation unit will contain instances of each of the templates it
+uses.  In a large program, this can lead to an unacceptable amount of code
+duplication.
+
+@item
+@opindex fexternal-templates
+Add @samp{#pragma interface} to all files containing template
+definitions.  For each of these files, add @samp{#pragma implementation
+"@var{filename}"} to the top of some @samp{.C} file which
+@samp{#include}s it.  Then compile everything with
+@option{-fexternal-templates}.  The templates will then only be expanded
+in the translation unit which implements them (i.e.@: has a @samp{#pragma
+implementation} line for the file where they live); all other files will
+use external references.  If you're lucky, everything should work
+properly.  If you get undefined symbol errors, you need to make sure
+that each template instance which is used in the program is used in the
+file which implements that template.  If you don't have any use for a
+particular instance in that file, you can just instantiate it
+explicitly, using the syntax from the latest C++ working paper:
+
+@example
+template class A<int>;
+template ostream& operator << (ostream&, const A<int>&);
+@end example
+
+This strategy will work with code written for either model.  If you are
+using code written for the Cfront model, the file containing a class
+template and the file containing its member templates should be
+implemented in the same translation unit.
+
+@item
+@opindex falt-external-templates
+A slight variation on this approach is to use the flag
+@option{-falt-external-templates} instead.  This flag causes template
+instances to be emitted in the translation unit that implements the
+header where they are first instantiated, rather than the one which
+implements the file where the templates are defined.  This header must
+be the same in all translation units, or things are likely to break.
+
+@xref{C++ Interface,,Declarations and Definitions in One Header}, for
+more discussion of these pragmas.
+@end enumerate
+
+@node Bound member functions
+@section Extracting the function pointer from a bound pointer to member function
+
+@cindex pmf
+@cindex pointer to member function
+@cindex bound pointer to member function
+
+In C++, pointer to member functions (PMFs) are implemented using a wide
+pointer of sorts to handle all the possible call mechanisms; the PMF
+needs to store information about how to adjust the @samp{this} pointer,
+and if the function pointed to is virtual, where to find the vtable, and
+where in the vtable to look for the member function.  If you are using
+PMFs in an inner loop, you should really reconsider that decision.  If
+that is not an option, you can extract the pointer to the function that
+would be called for a given object/PMF pair and call it directly inside
+the inner loop, to save a bit of time.
+
+Note that you will still be paying the penalty for the call through a
+function pointer; on most modern architectures, such a call defeats the
+branch prediction features of the CPU@.  This is also true of normal
+virtual function calls.
+
+The syntax for this extension is
+
+@example
+extern A a;
+extern int (A::*fp)();
+typedef int (*fptr)(A *);
+
+fptr p = (fptr)(a.*fp);
+@end example
+
+For PMF constants (i.e.@: expressions of the form @samp{&Klasse::Member}),
+no object is needed to obtain the address of the function.  They can be
+converted to function pointers directly:
+
+@example
+fptr p1 = (fptr)(&A::foo);
+@end example
+
+@opindex Wno-pmf-conversions
+You must specify @option{-Wno-pmf-conversions} to use this extension.
+
+@node C++ Attributes
+@section C++-Specific Variable, Function, and Type Attributes
+
+Some attributes only make sense for C++ programs.
+
+@table @code
+@item init_priority (@var{priority})
+@cindex init_priority attribute
+
+
+In Standard C++, objects defined at namespace scope are guaranteed to be
+initialized in an order in strict accordance with that of their definitions
+@emph{in a given translation unit}.  No guarantee is made for initializations
+across translation units.  However, GNU C++ allows users to control the
+order of initialization of objects defined at namespace scope with the
+@code{init_priority} attribute by specifying a relative @var{priority},
+a constant integral expression currently bounded between 101 and 65535
+inclusive.  Lower numbers indicate a higher priority.
+
+In the following example, @code{A} would normally be created before
+@code{B}, but the @code{init_priority} attribute has reversed that order:
+
+@example
+Some_Class  A  __attribute__ ((init_priority (2000)));
+Some_Class  B  __attribute__ ((init_priority (543)));
+@end example
+
+@noindent
+Note that the particular values of @var{priority} do not matter; only their
+relative ordering.
+
+@item java_interface
+@cindex java_interface attribute
+
+This type attribute informs C++ that the class is a Java interface.  It may
+only be applied to classes declared within an @code{extern "Java"} block.
+Calls to methods declared in this interface will be dispatched using GCJ's
+interface table mechanism, instead of regular virtual table dispatch.
+
+@end table
+
+@node Java Exceptions
+@section Java Exceptions
+
+The Java language uses a slightly different exception handling model
+from C++.  Normally, GNU C++ will automatically detect when you are
+writing C++ code that uses Java exceptions, and handle them
+appropriately.  However, if C++ code only needs to execute destructors
+when Java exceptions are thrown through it, GCC will guess incorrectly.
+Sample problematic code is:
+
+@example
+  struct S @{ ~S(); @};
+  extern void bar();    // is written in Java, and may throw exceptions
+  void foo()
+  @{
+    S s;
+    bar();
+  @}
+@end example
+
+@noindent
+The usual effect of an incorrect guess is a link failure, complaining of
+a missing routine called @samp{__gxx_personality_v0}.
+
+You can inform the compiler that Java exceptions are to be used in a
+translation unit, irrespective of what it might think, by writing
+@samp{@w{#pragma GCC java_exceptions}} at the head of the file.  This
+@samp{#pragma} must appear before any functions that throw or catch
+exceptions, or run destructors when exceptions are thrown through them.
+
+You cannot mix Java and C++ exceptions in the same translation unit.  It
+is believed to be safe to throw a C++ exception from one file through
+another file compiled for the Java exception model, or vice versa, but
+there may be bugs in this area.
+
+@node Deprecated Features
+@section Deprecated Features
+
+In the past, the GNU C++ compiler was extended to experiment with new
+features, at a time when the C++ language was still evolving.  Now that
+the C++ standard is complete, some of those features are superseded by
+superior alternatives.  Using the old features might cause a warning in
+some cases that the feature will be dropped in the future.  In other
+cases, the feature might be gone already.
+
+While the list below is not exhaustive, it documents some of the options
+that are now deprecated:
+
+@table @code
+@item -fexternal-templates
+@itemx -falt-external-templates
+These are two of the many ways for g++ to implement template
+instantiation.  @xref{Template Instantiation}.  The C++ standard clearly
+defines how template definitions have to be organized across
+implementation units.  g++ has an implicit instantiation mechanism that
+should work just fine for standard-conforming code.
+
+@item -fstrict-prototype
+@itemx -fno-strict-prototype
+Previously it was possible to use an empty prototype parameter list to
+indicate an unspecified number of parameters (like C), rather than no
+parameters, as C++ demands.  This feature has been removed, except where
+it is required for backwards compatibility @xref{Backwards Compatibility}.
+@end table
+
+The named return value extension has been deprecated, and is now
+removed from g++.
+
+The use of initializer lists with new expressions has been deprecated,
+and is now removed from g++.
+
+Floating and complex non-type template parameters have been deprecated,
+and are now removed from g++.
+
+The implicit typename extension has been deprecated and will be removed
+from g++ at some point.  In some cases g++ determines that a dependant
+type such as @code{TPL<T>::X} is a type without needing a
+@code{typename} keyword, contrary to the standard.
+
+@node Backwards Compatibility
+@section Backwards Compatibility
+@cindex Backwards Compatibility
+@cindex ARM [Annotated C++ Reference Manual]
+
+Now that there is a definitive ISO standard C++, G++ has a specification
+to adhere to.  The C++ language evolved over time, and features that
+used to be acceptable in previous drafts of the standard, such as the ARM
+[Annotated C++ Reference Manual], are no longer accepted.  In order to allow
+compilation of C++ written to such drafts, G++ contains some backwards
+compatibilities.  @emph{All such backwards compatibility features are
+liable to disappear in future versions of G++.} They should be considered
+deprecated @xref{Deprecated Features}.
+
+@table @code
+@item For scope
+If a variable is declared at for scope, it used to remain in scope until
+the end of the scope which contained the for statement (rather than just
+within the for scope).  G++ retains this, but issues a warning, if such a
+variable is accessed outside the for scope.
+
+@item Implicit C language
+Old C system header files did not contain an @code{extern "C" @{@dots{}@}}
+scope to set the language.  On such systems, all header files are
+implicitly scoped inside a C language scope.  Also, an empty prototype
+@code{()} will be treated as an unspecified number of arguments, rather
+than no arguments, as C++ demands.
+@end table
diff --git a/contrib/gcc/doc/fragments.texi b/contrib/gcc/doc/fragments.texi
new file mode 100644
index 0000000..f9ef3d2
--- /dev/null
+++ b/contrib/gcc/doc/fragments.texi
@@ -0,0 +1,190 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+@c 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Fragments
+@chapter Makefile Fragments
+@cindex makefile fragment
+
+When you configure GCC using the @file{configure} script, it will
+construct the file @file{Makefile} from the template file
+@file{Makefile.in}.  When it does this, it can incorporate makefile
+fragments from the @file{config} directory.  These are used to set
+Makefile parameters that are not amenable to being calculated by
+autoconf.  The list of fragments to incorporate is set by
+@file{config.gcc}; @xref{System Config}.
+
+Fragments are named either @file{t-@var{target}} or @file{x-@var{host}},
+depending on whether they are relevant to configuring GCC to produce
+code for a particular target, or to configuring GCC to run on a
+particular host.  Here @var{target} and @var{host} are mnemonics
+which usually have some relationship to the canonical system name, but
+no formal connection.
+
+If these files do not exist, it means nothing needs to be added for a
+given target or host.  Most targets need a few @file{t-@var{target}}
+fragments, but needing @file{x-@var{host}} fragments is rare.
+
+@menu
+* Target Fragment:: Writing @file{t-@var{target}} files.
+* Host Fragment::   Writing @file{x-@var{host}} files.
+@end menu
+
+@node Target Fragment
+@section Target Makefile Fragments
+@cindex target makefile fragment
+@cindex @file{t-@var{target}}
+
+Target makefile fragments can set these Makefile variables.
+
+@table @code
+@findex LIBGCC2_CFLAGS
+@item LIBGCC2_CFLAGS
+Compiler flags to use when compiling @file{libgcc2.c}.
+
+@findex LIB2FUNCS_EXTRA
+@item LIB2FUNCS_EXTRA
+A list of source file names to be compiled or assembled and inserted
+into @file{libgcc.a}.
+
+@findex Floating Point Emulation
+@item Floating Point Emulation
+To have GCC include software floating point libraries in @file{libgcc.a}
+define @code{FPBIT} and @code{DPBIT} along with a few rules as follows:
+@smallexample
+# We want fine grained libraries, so use the new code
+# to build the floating point emulation libraries.
+FPBIT = fp-bit.c
+DPBIT = dp-bit.c
+
+
+fp-bit.c: $(srcdir)/config/fp-bit.c
+        echo '#define FLOAT' > fp-bit.c
+        cat $(srcdir)/config/fp-bit.c >> fp-bit.c
+
+dp-bit.c: $(srcdir)/config/fp-bit.c
+        cat $(srcdir)/config/fp-bit.c > dp-bit.c
+@end smallexample
+
+You may need to provide additional #defines at the beginning of @file{fp-bit.c}
+and @file{dp-bit.c} to control target endianness and other options.
+
+
+@findex CRTSTUFF_T_CFLAGS
+@item CRTSTUFF_T_CFLAGS
+Special flags used when compiling @file{crtstuff.c}.
+@xref{Initialization}.
+
+@findex CRTSTUFF_T_CFLAGS_S
+@item CRTSTUFF_T_CFLAGS_S
+Special flags used when compiling @file{crtstuff.c} for shared
+linking.  Used if you use @file{crtbeginS.o} and @file{crtendS.o}
+in @code{EXTRA-PARTS}.
+@xref{Initialization}.
+
+@findex MULTILIB_OPTIONS
+@item MULTILIB_OPTIONS
+For some targets, invoking GCC in different ways produces objects
+that can not be linked together.  For example, for some targets GCC
+produces both big and little endian code.  For these targets, you must
+arrange for multiple versions of @file{libgcc.a} to be compiled, one for
+each set of incompatible options.  When GCC invokes the linker, it
+arranges to link in the right version of @file{libgcc.a}, based on
+the command line options used.
+
+The @code{MULTILIB_OPTIONS} macro lists the set of options for which
+special versions of @file{libgcc.a} must be built.  Write options that
+are mutually incompatible side by side, separated by a slash.  Write
+options that may be used together separated by a space.  The build
+procedure will build all combinations of compatible options.
+
+For example, if you set @code{MULTILIB_OPTIONS} to @samp{m68000/m68020
+msoft-float}, @file{Makefile} will build special versions of
+@file{libgcc.a} using the following sets of options:  @option{-m68000},
+@option{-m68020}, @option{-msoft-float}, @samp{-m68000 -msoft-float}, and
+@samp{-m68020 -msoft-float}.
+
+@findex MULTILIB_DIRNAMES
+@item MULTILIB_DIRNAMES
+If @code{MULTILIB_OPTIONS} is used, this variable specifies the
+directory names that should be used to hold the various libraries.
+Write one element in @code{MULTILIB_DIRNAMES} for each element in
+@code{MULTILIB_OPTIONS}.  If @code{MULTILIB_DIRNAMES} is not used, the
+default value will be @code{MULTILIB_OPTIONS}, with all slashes treated
+as spaces.
+
+For example, if @code{MULTILIB_OPTIONS} is set to @samp{m68000/m68020
+msoft-float}, then the default value of @code{MULTILIB_DIRNAMES} is
+@samp{m68000 m68020 msoft-float}.  You may specify a different value if
+you desire a different set of directory names.
+
+@findex MULTILIB_MATCHES
+@item MULTILIB_MATCHES
+Sometimes the same option may be written in two different ways.  If an
+option is listed in @code{MULTILIB_OPTIONS}, GCC needs to know about
+any synonyms.  In that case, set @code{MULTILIB_MATCHES} to a list of
+items of the form @samp{option=option} to describe all relevant
+synonyms.  For example, @samp{m68000=mc68000 m68020=mc68020}.
+
+@findex MULTILIB_EXCEPTIONS
+@item MULTILIB_EXCEPTIONS
+Sometimes when there are multiple sets of @code{MULTILIB_OPTIONS} being
+specified, there are combinations that should not be built.  In that
+case, set @code{MULTILIB_EXCEPTIONS} to be all of the switch exceptions
+in shell case syntax that should not be built.
+
+For example, in the PowerPC embedded ABI support, it is not desirable
+to build libraries compiled with the @option{-mcall-aix} option
+and either of the @option{-fleading-underscore} or @option{-mlittle} options
+at the same time.  Therefore @code{MULTILIB_EXCEPTIONS} is set to
+@smallexample
+*mcall-aix/*fleading-underscore* *mlittle/*mcall-aix*
+@end smallexample
+
+@findex MULTILIB_EXTRA_OPTS
+@item MULTILIB_EXTRA_OPTS
+Sometimes it is desirable that when building multiple versions of
+@file{libgcc.a} certain options should always be passed on to the
+compiler.  In that case, set @code{MULTILIB_EXTRA_OPTS} to be the list
+of options to be used for all builds.
+@end table
+
+@node Host Fragment
+@section Host Makefile Fragments
+@cindex host makefile fragment
+@cindex @file{x-@var{host}}
+
+The use of @file{x-@var{host}} fragments is discouraged.  You should do
+so only if there is no other mechanism to get the behavior desired.
+Host fragments should never forcibly override variables set by the
+configure script, as they may have been adjusted by the user.
+
+Variables provided for host fragments to set include:
+
+@table @code
+
+@item X_CFLAGS
+@itemx X_CPPFLAGS
+These are extra flags to pass to the C compiler and preprocessor,
+respectively.  They are used both when building GCC, and when compiling
+things with the just-built GCC.
+
+@item XCFLAGS
+These are extra flags to use when building the compiler.  They are not
+used when compiling @file{libgcc.a}.  However, they @emph{are} used when
+recompiling the compiler with itself in later stages of a bootstrap.
+
+@item BOOT_LDFLAGS
+Flags to be passed to the linker when recompiling the compiler with
+itself in later stages of a bootstrap.  You might need to use this if,
+for instance, one of the front ends needs more text space than the
+linker provides by default.
+
+@item EXTRA_PROGRAMS
+A list of additional programs required to use the compiler on this host,
+which should be compiled with GCC and installed alongside the front
+ends.  If you set this variable, you must also provide rules to build
+the extra programs.
+
+@end table
diff --git a/contrib/gcc/doc/frontends.texi b/contrib/gcc/doc/frontends.texi
new file mode 100644
index 0000000..ffaa9aa
--- /dev/null
+++ b/contrib/gcc/doc/frontends.texi
@@ -0,0 +1,70 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+@c 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node G++ and GCC
+@chapter Compile C, C++, Objective-C, Ada, CHILL, Fortran, or Java
+
+@cindex Objective-C
+@cindex Fortran
+@cindex Java
+@cindex CHILL
+@cindex Ada
+Several versions of the compiler (C, C++, Objective-C, Ada, CHILL,
+Fortran, and Java) are integrated; this is why we use the name
+``GNU Compiler Collection''.  GCC can compile programs written in any of these
+languages.  The Ada, CHILL, Fortran, and Java compilers are described in
+separate manuals.
+
+@cindex GCC
+``GCC'' is a common shorthand term for the GNU Compiler Collection.  This is both
+the most general name for the compiler, and the name used when the
+emphasis is on compiling C programs (as the abbreviation formerly
+stood for ``GNU C Compiler'').
+
+@cindex C++
+@cindex G++
+When referring to C++ compilation, it is usual to call the compiler
+``G++''.  Since there is only one compiler, it is also accurate to call
+it ``GCC'' no matter what the language context; however, the term
+``G++'' is more useful when the emphasis is on compiling C++ programs.
+
+@cindex Ada
+@cindex GNAT
+Similarly, when we talk about Ada compilation, we usually call the
+compiler ``GNAT'', for the same reasons.
+
+We use the name ``GCC'' to refer to the compilation system as a
+whole, and more specifically to the language-independent part of the
+compiler.  For example, we refer to the optimization options as
+affecting the behavior of ``GCC'' or sometimes just ``the compiler''.
+
+Front ends for other languages, such as Mercury and Pascal exist but
+have not yet been integrated into GCC@.  These front ends, like that for C++,
+are built in subdirectories of GCC and link to it.  The result is an
+integrated compiler that can compile programs written in C, C++,
+Objective-C, or any of the languages for which you have installed front
+ends.
+
+In this manual, we only discuss the options for the C, Objective-C, and
+C++ compilers and those of the GCC core.  Consult the documentation
+of the other front ends for the options to use when compiling programs
+written in other languages.
+
+@cindex compiler compared to C++ preprocessor
+@cindex intermediate C version, nonexistent
+@cindex C intermediate output, nonexistent
+G++ is a @emph{compiler}, not merely a preprocessor.  G++ builds object
+code directly from your C++ program source.  There is no intermediate C
+version of the program.  (By contrast, for example, some other
+implementations use a program that generates a C program from your C++
+source.)  Avoiding an intermediate C representation of the program means
+that you get better object code, and better debugging information.  The
+GNU debugger, GDB, works with this information in the object code to
+give you comprehensive C++ source-level editing capabilities
+(@pxref{C,,C and C++,gdb.info, Debugging with GDB}).
+
+@c FIXME!  Someone who knows something about Objective-C ought to put in
+@c a paragraph or two about it here, and move the index entry down when
+@c there is more to point to than the general mention in the 1st par.
diff --git a/contrib/gcc/doc/gcc.texi b/contrib/gcc/doc/gcc.texi
new file mode 100644
index 0000000..d8579e7
--- /dev/null
+++ b/contrib/gcc/doc/gcc.texi
@@ -0,0 +1,234 @@
+\input texinfo  @c -*-texinfo-*-
+@c %**start of header
+@setfilename gcc.info
+@c INTERNALS is used by md.texi to determine whether to include the
+@c whole of that file, in the internals manual, or only the part
+@c dealing with constraints, in the user manual.
+@clear INTERNALS
+
+@c NOTE: checks/things to do:
+@c
+@c -have bob do a search in all seven files for "mew" (ideally --mew,
+@c  but i may have forgotten the occasional "--"..).
+@c     Just checked... all have `--'!  Bob 22Jul96
+@c     Use this to search:   grep -n '\-\-mew' *.texi
+@c -item/itemx, text after all (sub/sub)section titles, etc..
+@c -consider putting the lists of options on pp 17--> etc in columns or
+@c  some such.
+@c -overfulls.  do a search for "mew" in the files, and you will see
+@c   overfulls that i noted but could not deal with.
+@c -have to add text:  beginning of chapter 8
+
+@c
+@c anything else?                       --mew 10feb93
+
+@include gcc-common.texi
+
+@settitle Using the GNU Compiler Collection (GCC)
+
+@c Create a separate index for command line options.
+@defcodeindex op
+@c Merge the standard indexes into a single one.
+@syncodeindex fn cp
+@syncodeindex vr cp
+@syncodeindex ky cp
+@syncodeindex pg cp
+@syncodeindex tp cp
+
+@c %**end of header
+
+@c Use with @@smallbook.
+
+@c Cause even numbered pages to be printed on the left hand side of
+@c the page and odd numbered pages to be printed on the right hand
+@c side of the page.  Using this, you can print on both sides of a
+@c sheet of paper and have the text on the same part of the sheet.
+
+@c The text on right hand pages is pushed towards the right hand
+@c margin and the text on left hand pages is pushed toward the left
+@c hand margin.
+@c (To provide the reverse effect, set bindingoffset to -0.75in.)
+
+@c @tex
+@c \global\bindingoffset=0.75in
+@c \global\normaloffset =0.75in
+@c @end tex
+
+@c Change the font used for @def... commands, since the default
+@c proportional one used is bad for names starting __.
+@tex
+\global\setfont\defbf\ttbshape{10}{\magstep1}
+@end tex
+
+@macro copyrightnotice
+Copyright @copyright{} 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+@end macro
+@ifnottex
+@dircategory Programming
+@direntry
+* gcc: (gcc).                  The GNU Compiler Collection.
+@end direntry
+This file documents the use of the GNU compilers.
+@sp 1
+Published by the Free Software Foundation@*
+59 Temple Place - Suite 330@*
+Boston, MA 02111-1307 USA
+@sp 1
+@copyrightnotice{}
+@sp 1
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.1 or
+any later version published by the Free Software Foundation; with the
+Invariant Sections being ``GNU General Public License'' and ``Funding
+Free Software'', the Front-Cover texts being (a) (see below), and with
+the Back-Cover Texts being (b) (see below).  A copy of the license is
+included in the section entitled ``GNU Free Documentation License''.
+
+(a) The FSF's Front-Cover Text is:
+
+     A GNU Manual
+
+(b) The FSF's Back-Cover Text is:
+
+     You have freedom to copy and modify this GNU Manual, like GNU
+     software.  Copies published by the Free Software Foundation raise
+     funds for GNU development.
+@end ifnottex
+
+@setchapternewpage odd
+@titlepage
+@center @titlefont{Using the GNU Compiler Collection}
+@sp 2
+@center Richard M. Stallman
+@sp 3
+@center Last updated 7 January 2002
+@sp 1
+
+@center for GCC @value{version-GCC}
+@page
+@vskip 0pt plus 1filll
+@copyrightnotice{}
+@sp 2
+For GCC Version @value{version-GCC}@*
+@sp 1
+Published by the Free Software Foundation @*
+59 Temple Place---Suite 330@*
+Boston, MA 02111-1307, USA@*
+Last printed April, 1998.@*
+Printed copies are available for $50 each.@*
+@c Update this ISBN when printing a new edition.
+@ifset FSFPRINT
+ISBN 1-882114-37-X
+@end ifset
+@sp 1
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.1 or
+any later version published by the Free Software Foundation; with the
+Invariant Sections being ``GNU General Public License'', the Front-Cover
+texts being (a) (see below), and with the Back-Cover Texts being (b)
+(see below).  A copy of the license is included in the section entitled
+``GNU Free Documentation License''.
+
+(a) The FSF's Front-Cover Text is:
+
+     A GNU Manual
+
+(b) The FSF's Back-Cover Text is:
+
+     You have freedom to copy and modify this GNU Manual, like GNU
+     software.  Copies published by the Free Software Foundation raise
+     funds for GNU development.
+@end titlepage
+@summarycontents
+@contents
+@page
+
+@node Top, G++ and GCC,, (DIR)
+@top Introduction
+@cindex introduction
+
+This manual documents how to use the GNU compilers,
+as well as their features and incompatibilities, and how to report
+bugs.  It corresponds to GCC version @value{version-GCC}.
+The internals of the GNU compilers, including how to port them to new
+targets and some information about how to write front ends for new
+languages, are documented in a separate manual.  @xref{Top,,
+Introduction, gccint, GNU Compiler Collection (GCC) Internals}.
+
+@menu
+* G++ and GCC::     You can compile C or C++ programs.
+* Standards::       Language standards supported by GCC.
+* Invoking GCC::    Command options supported by @samp{gcc}.
+* C Implementation:: How GCC implements the ISO C specification.
+* C Extensions::    GNU extensions to the C language family.
+* C++ Extensions::  GNU extensions to the C++ language.
+* Objective-C::     GNU Objective-C runtime features.
+* Gcov::	    gcov: a GCC test coverage program.
+* Trouble::         If you have trouble using GCC.
+* Bugs::            How, why and where to report bugs.
+* Service::         How to find suppliers of support for GCC.
+* Contributing::    How to contribute to testing and developing GCC.
+* VMS::             Using GCC on VMS.
+
+* Funding::         How to help assure funding for free software.
+* GNU Project::     The GNU Project and GNU/Linux.
+
+* Copying::         GNU General Public License says
+                     how you can copy and share GCC.
+* GNU Free Documentation License:: How you can copy and share this manual.
+* Contributors::    People who have contributed to GCC.
+
+* Option Index::    Index to command line options.
+* Index::	    Index of concepts and symbol names.
+@end menu
+
+@include frontends.texi
+@include standards.texi
+@include invoke.texi
+@include extend.texi
+@include objc.texi
+@include gcov.texi
+@include trouble.texi
+@include bugreport.texi
+@include service.texi
+@include contribute.texi
+@include vms.texi
+
+@include funding.texi
+@include gnu.texi
+@include gpl.texi
+
+@c ---------------------------------------------------------------------
+@c GFDL
+@c ---------------------------------------------------------------------
+
+@include fdl.texi
+
+@include contrib.texi
+
+@c ---------------------------------------------------------------------
+@c Indexes
+@c ---------------------------------------------------------------------
+
+@node Option Index
+@unnumbered Option Index
+
+GCC's command line options are indexed here without any initial @samp{-}
+or @samp{--}.  Where an option has both positive and negative forms
+(such as @option{-f@var{option}} and @option{-fno-@var{option}}),
+relevant entries in the manual are indexed under the most appropriate
+form; it may sometimes be useful to look up both forms.
+
+@printindex op
+
+@node Index
+@unnumbered Index
+
+@printindex cp
+
+@c ---------------------------------------------------------------------
+@c Epilogue
+@c ---------------------------------------------------------------------
+
+@bye
diff --git a/contrib/gcc/doc/gccint.texi b/contrib/gcc/doc/gccint.texi
new file mode 100644
index 0000000..82a7d31
--- /dev/null
+++ b/contrib/gcc/doc/gccint.texi
@@ -0,0 +1,236 @@
+\input texinfo  @c -*-texinfo-*-
+@c %**start of header
+@setfilename gccint.info
+@c INTERNALS is used by md.texi to determine whether to include the
+@c whole of that file, in the internals manual, or only the part
+@c dealing with constraints, in the user manual.
+@set INTERNALS
+
+@c See miscellaneous notes in gcc.texi on checks/things to do.
+
+@include gcc-common.texi
+
+@settitle GNU Compiler Collection (GCC) Internals
+
+@c Create a separate index for command line options.
+@defcodeindex op
+@c Merge the standard indexes into a single one.
+@syncodeindex fn cp
+@syncodeindex vr cp
+@syncodeindex ky cp
+@syncodeindex pg cp
+@syncodeindex tp cp
+
+@c %**end of header
+
+@c Use with @@smallbook.
+
+@c Cause even numbered pages to be printed on the left hand side of
+@c the page and odd numbered pages to be printed on the right hand
+@c side of the page.  Using this, you can print on both sides of a
+@c sheet of paper and have the text on the same part of the sheet.
+
+@c The text on right hand pages is pushed towards the right hand
+@c margin and the text on left hand pages is pushed toward the left
+@c hand margin.
+@c (To provide the reverse effect, set bindingoffset to -0.75in.)
+
+@c @tex
+@c \global\bindingoffset=0.75in
+@c \global\normaloffset =0.75in
+@c @end tex
+
+@c Change the font used for @def... commands, since the default
+@c proportional one used is bad for names starting __.
+@tex
+\global\setfont\defbf\ttbshape{10}{\magstep1}
+@end tex
+
+@macro copyrightnotice
+Copyright @copyright{} 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+@end macro
+@ifnottex
+@dircategory Programming
+@direntry
+* gccint: (gccint).            Internals of the GNU Compiler Collection.
+@end direntry
+This file documents the internals of the GNU compilers.
+@sp 1
+Published by the Free Software Foundation@*
+59 Temple Place - Suite 330@*
+Boston, MA 02111-1307 USA
+@sp 1
+@copyrightnotice{}
+@sp 1
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.1 or
+any later version published by the Free Software Foundation; with the
+Invariant Sections being ``GNU General Public License'' and ``Funding
+Free Software'', the Front-Cover texts being (a) (see below), and with
+the Back-Cover Texts being (b) (see below).  A copy of the license is
+included in the section entitled ``GNU Free Documentation License''.
+
+(a) The FSF's Front-Cover Text is:
+
+     A GNU Manual
+
+(b) The FSF's Back-Cover Text is:
+
+     You have freedom to copy and modify this GNU Manual, like GNU
+     software.  Copies published by the Free Software Foundation raise
+     funds for GNU development.
+@end ifnottex
+
+@setchapternewpage odd
+@titlepage
+@center @titlefont{GNU Compiler Collection Internals}
+@sp 2
+@center Richard M. Stallman
+@sp 3
+@center Last updated 10 January 2002
+@sp 1
+
+@center for GCC @value{version-GCC}
+@page
+@vskip 0pt plus 1filll
+@copyrightnotice{}
+@sp 2
+For GCC Version @value{version-GCC}@*
+@sp 1
+Published by the Free Software Foundation @*
+59 Temple Place---Suite 330@*
+Boston, MA 02111-1307, USA@*
+Last printed April, 1998.@*
+Printed copies are available for $50 each.@*
+@c Update this ISBN when printing a new edition.
+@ifset FSFPRINT
+ISBN 1-882114-37-X
+@end ifset
+@sp 1
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.1 or
+any later version published by the Free Software Foundation; with the
+Invariant Sections being ``GNU General Public License'', the Front-Cover
+texts being (a) (see below), and with the Back-Cover Texts being (b)
+(see below).  A copy of the license is included in the section entitled
+``GNU Free Documentation License''.
+
+(a) The FSF's Front-Cover Text is:
+
+     A GNU Manual
+
+(b) The FSF's Back-Cover Text is:
+
+     You have freedom to copy and modify this GNU Manual, like GNU
+     software.  Copies published by the Free Software Foundation raise
+     funds for GNU development.
+@end titlepage
+@summarycontents
+@contents
+@page
+
+@node Top, Contributing,, (DIR)
+@top Introduction
+@cindex introduction
+
+This manual documents the internals of the GNU compilers, including
+how to port them to new targets and some information about how to
+write front ends for new languages.  It corresponds to GCC version
+@value{version-GCC}.  The use of the GNU compilers is documented in a
+separate manual.  @xref{Top,, Introduction, gcc, Using the GNU
+Compiler Collection (GCC)}.
+
+This manual is mainly a reference manual rather than a tutorial.  It
+discusses how to contribute to GCC (@pxref{Contributing}), the
+characteristics of the machines supported by GCC as hosts and targets
+(@pxref{Portability}), how GCC relates to the ABIs on such systems
+(@pxref{Interface}), and the characteristics of the languages for
+which GCC front ends are written (@pxref{Languages}).  It then
+describes the GCC source tree structure and build system, some of the
+interfaces to GCC front ends, and how support for a target system is
+implemented in GCC@.
+
+Additional tutorial information is linked to from
+@uref{http://gcc.gnu.org/readings.html}.
+
+@menu
+* Contributing::    How to contribute to testing and developing GCC.
+* Portability::     Goals of GCC's portability features.
+* Interface::       Function-call interface of GCC output.
+* Languages::       Languages for which GCC front ends are written.
+* Source Tree::     GCC source tree structure and build system.
+* Passes::          Order of passes, what they do, and what each file is for.
+* Trees::           The source representation used by the C and C++ front ends.
+* RTL::             The intermediate representation that most passes work on.
+* Machine Desc::    How to write machine description instruction patterns.
+* Target Macros::   How to write the machine description C macros and functions.
+* Host Config::     Writing the @file{xm-@var{machine}.h} file.
+* Fragments::       Writing the @file{t-@var{target}} and @file{x-@var{host}} files.
+* Collect2::        How @code{collect2} works; how it finds @code{ld}.
+* Header Dirs::     Understanding the standard header file directories.
+
+* Funding::         How to help assure funding for free software.
+* GNU Project::     The GNU Project and GNU/Linux.
+
+* Copying::         GNU General Public License says
+                     how you can copy and share GCC.
+* GNU Free Documentation License:: How you can copy and share this manual.
+* Contributors::    People who have contributed to GCC.
+
+* Option Index::    Index to command line options.
+* Index::	    Index of concepts and symbol names.
+@end menu
+
+@include contribute.texi
+@include portability.texi
+@include interface.texi
+@include languages.texi
+@include sourcebuild.texi
+@include passes.texi
+@include c-tree.texi
+@include rtl.texi
+@include md.texi
+@include tm.texi
+@include hostconfig.texi
+@include fragments.texi
+@include collect2.texi
+@include headerdirs.texi
+
+@include funding.texi
+@include gnu.texi
+@include gpl.texi
+
+@c ---------------------------------------------------------------------
+@c GFDL
+@c ---------------------------------------------------------------------
+
+@include fdl.texi
+
+@include contrib.texi
+
+@c ---------------------------------------------------------------------
+@c Indexes
+@c ---------------------------------------------------------------------
+
+@node Option Index
+@unnumbered Option Index
+
+GCC's command line options are indexed here without any initial @samp{-}
+or @samp{--}.  Where an option has both positive and negative forms
+(such as @option{-f@var{option}} and @option{-fno-@var{option}}),
+relevant entries in the manual are indexed under the most appropriate
+form; it may sometimes be useful to look up both forms.
+
+@printindex op
+
+@node Index
+@unnumbered Index
+
+@printindex cp
+
+@c ---------------------------------------------------------------------
+@c Epilogue
+@c ---------------------------------------------------------------------
+
+@bye
diff --git a/contrib/gcc/doc/gcov.texi b/contrib/gcc/doc/gcov.texi
new file mode 100644
index 0000000..86b64e0
--- /dev/null
+++ b/contrib/gcc/doc/gcov.texi
@@ -0,0 +1,406 @@
+@c Copyright (C) 1996, 1997, 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@ignore
+@c man begin COPYRIGHT
+Copyright @copyright{} 1996, 1997, 1999, 2000, 2001 Free Software Foundation, Inc.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.1 or
+any later version published by the Free Software Foundation; with the
+Invariant Sections being ``GNU General Public License'' and ``Funding
+Free Software'', the Front-Cover texts being (a) (see below), and with
+the Back-Cover Texts being (b) (see below).  A copy of the license is
+included in the gfdl(7) man page.
+
+(a) The FSF's Front-Cover Text is:
+
+     A GNU Manual
+
+(b) The FSF's Back-Cover Text is:
+
+     You have freedom to copy and modify this GNU Manual, like GNU
+     software.  Copies published by the Free Software Foundation raise
+     funds for GNU development.
+@c man end
+@c Set file name and title for the man page.
+@setfilename gcov
+@settitle coverage testing tool
+@end ignore
+
+@node Gcov
+@chapter @command{gcov}: a Test Coverage Program
+
+@command{gcov} is a tool you can use in conjunction with GCC to
+test code coverage in your programs.
+
+@menu
+* Gcov Intro::         	        Introduction to gcov.
+* Invoking Gcov::       	How to use gcov.
+* Gcov and Optimization::       Using gcov with GCC optimization.
+* Gcov Data Files::             The files used by gcov.
+@end menu
+
+@node Gcov Intro
+@section Introduction to @command{gcov}
+@c man begin DESCRIPTION
+
+@command{gcov} is a test coverage program.  Use it in concert with GCC
+to analyze your programs to help create more efficient, faster
+running code.  You can use @command{gcov} as a profiling tool to help
+discover where your optimization efforts will best affect your code.  You
+can also use @command{gcov} along with the other profiling tool,
+@command{gprof}, to assess which parts of your code use the greatest amount
+of computing time.
+
+Profiling tools help you analyze your code's performance.  Using a
+profiler such as @command{gcov} or @command{gprof}, you can find out some
+basic performance statistics, such as:
+
+@itemize @bullet
+@item
+how often each line of code executes
+
+@item
+what lines of code are actually executed
+
+@item
+how much computing time each section of code uses
+@end itemize
+
+Once you know these things about how your code works when compiled, you
+can look at each module to see which modules should be optimized.
+@command{gcov} helps you determine where to work on optimization.
+
+Software developers also use coverage testing in concert with
+testsuites, to make sure software is actually good enough for a release.
+Testsuites can verify that a program works as expected; a coverage
+program tests to see how much of the program is exercised by the
+testsuite.  Developers can then determine what kinds of test cases need
+to be added to the testsuites to create both better testing and a better
+final product.
+
+You should compile your code without optimization if you plan to use
+@command{gcov} because the optimization, by combining some lines of code
+into one function, may not give you as much information as you need to
+look for `hot spots' where the code is using a great deal of computer
+time.  Likewise, because @command{gcov} accumulates statistics by line (at
+the lowest resolution), it works best with a programming style that
+places only one statement on each line.  If you use complicated macros
+that expand to loops or to other control structures, the statistics are
+less helpful---they only report on the line where the macro call
+appears.  If your complex macros behave like functions, you can replace
+them with inline functions to solve this problem.
+
+@command{gcov} creates a logfile called @file{@var{sourcefile}.gcov} which
+indicates how many times each line of a source file @file{@var{sourcefile}.c}
+has executed.  You can use these logfiles along with @command{gprof} to aid
+in fine-tuning the performance of your programs.  @command{gprof} gives
+timing information you can use along with the information you get from
+@command{gcov}.
+
+@command{gcov} works only on code compiled with GCC@.  It is not
+compatible with any other profiling or test coverage mechanism.
+
+@c man end
+
+@node Invoking Gcov
+@section Invoking gcov
+
+@smallexample
+gcov @r{[}@var{options}@r{]} @var{sourcefile}
+@end smallexample
+
+@command{gcov} accepts the following options:
+
+@ignore
+@c man begin SYNOPSIS
+gcov [@option{-v}|@option{--version}] [@option{-h}|@option{--help}]
+     [@option{-b}|@option{--branch-probabilities}] [@option{-c}|@option{--branch-counts}]
+     [@option{-n}|@option{--no-output}] [@option{-l}|@option{--long-file-names}]
+     [@option{-f}|@option{--function-summaries}]
+     [@option{-o}|@option{--object-directory} @var{directory}] @var{sourcefile}
+@c man end
+@c man begin SEEALSO
+gpl(7), gfdl(7), fsf-funding(7), gcc(1) and the Info entry for @file{gcc}.
+@c man end
+@end ignore
+
+@c man begin OPTIONS
+@table @gcctabopt
+@item -h
+@itemx --help
+Display help about using @command{gcov} (on the standard output), and
+exit without doing any further processing.
+
+@item -v
+@itemx --version
+Display the @command{gcov} version number (on the standard output),
+and exit without doing any further processing.
+
+@item -b
+@itemx --branch-probabilities
+Write branch frequencies to the output file, and write branch summary
+info to the standard output.  This option allows you to see how often
+each branch in your program was taken.
+
+@item -c
+@itemx --branch-counts
+Write branch frequencies as the number of branches taken, rather than
+the percentage of branches taken.
+
+@item -n
+@itemx --no-output
+Do not create the @command{gcov} output file.
+
+@item -l
+@itemx --long-file-names
+Create long file names for included source files.  For example, if the
+header file @file{x.h} contains code, and was included in the file
+@file{a.c}, then running @command{gcov} on the file @file{a.c} will produce
+an output file called @file{a.c.x.h.gcov} instead of @file{x.h.gcov}.
+This can be useful if @file{x.h} is included in multiple source files.
+
+@item -f
+@itemx --function-summaries
+Output summaries for each function in addition to the file level summary.
+
+@item -o @var{directory}
+@itemx --object-directory @var{directory}
+The directory where the object files live.  Gcov will search for @file{.bb},
+@file{.bbg}, and @file{.da} files in this directory.
+@end table
+
+@need 3000
+When using @command{gcov}, you must first compile your program with two
+special GCC options: @samp{-fprofile-arcs -ftest-coverage}.
+This tells the compiler to generate additional information needed by
+gcov (basically a flow graph of the program) and also includes
+additional code in the object files for generating the extra profiling
+information needed by gcov.  These additional files are placed in the
+directory where the source code is located.
+
+Running the program will cause profile output to be generated.  For each
+source file compiled with @option{-fprofile-arcs}, an accompanying @file{.da}
+file will be placed in the source directory.
+
+Running @command{gcov} with your program's source file names as arguments
+will now produce a listing of the code along with frequency of execution
+for each line.  For example, if your program is called @file{tmp.c}, this
+is what you see when you use the basic @command{gcov} facility:
+
+@smallexample
+$ gcc -fprofile-arcs -ftest-coverage tmp.c
+$ a.out
+$ gcov tmp.c
+ 87.50% of 8 source lines executed in file tmp.c
+Creating tmp.c.gcov.
+@end smallexample
+
+The file @file{tmp.c.gcov} contains output from @command{gcov}.
+Here is a sample:
+
+@smallexample
+                main()
+                @{
+           1      int i, total;
+
+           1      total = 0;
+
+          11      for (i = 0; i < 10; i++)
+          10        total += i;
+
+           1      if (total != 45)
+      ######        printf ("Failure\n");
+                  else
+           1        printf ("Success\n");
+           1    @}
+@end smallexample
+
+@need 450
+When you use the @option{-b} option, your output looks like this:
+
+@smallexample
+$ gcov -b tmp.c
+ 87.50% of 8 source lines executed in file tmp.c
+ 80.00% of 5 branches executed in file tmp.c
+ 80.00% of 5 branches taken at least once in file tmp.c
+ 50.00% of 2 calls executed in file tmp.c
+Creating tmp.c.gcov.
+@end smallexample
+
+Here is a sample of a resulting @file{tmp.c.gcov} file:
+
+@smallexample
+                main()
+                @{
+           1      int i, total;
+
+           1      total = 0;
+
+          11      for (i = 0; i < 10; i++)
+branch 0 taken = 91%
+branch 1 taken = 100%
+branch 2 taken = 100%
+          10        total += i;
+
+           1      if (total != 45)
+branch 0 taken = 100%
+      ######        printf ("Failure\n");
+call 0 never executed
+branch 1 never executed
+                  else
+           1        printf ("Success\n");
+call 0 returns = 100%
+           1    @}
+@end smallexample
+
+For each basic block, a line is printed after the last line of the basic
+block describing the branch or call that ends the basic block.  There can
+be multiple branches and calls listed for a single source line if there
+are multiple basic blocks that end on that line.  In this case, the
+branches and calls are each given a number.  There is no simple way to map
+these branches and calls back to source constructs.  In general, though,
+the lowest numbered branch or call will correspond to the leftmost construct
+on the source line.
+
+For a branch, if it was executed at least once, then a percentage
+indicating the number of times the branch was taken divided by the
+number of times the branch was executed will be printed.  Otherwise, the
+message ``never executed'' is printed.
+
+For a call, if it was executed at least once, then a percentage
+indicating the number of times the call returned divided by the number
+of times the call was executed will be printed.  This will usually be
+100%, but may be less for functions call @code{exit} or @code{longjmp},
+and thus may not return every time they are called.
+
+The execution counts are cumulative.  If the example program were
+executed again without removing the @file{.da} file, the count for the
+number of times each line in the source was executed would be added to
+the results of the previous run(s).  This is potentially useful in
+several ways.  For example, it could be used to accumulate data over a
+number of program runs as part of a test verification suite, or to
+provide more accurate long-term information over a large number of
+program runs.
+
+The data in the @file{.da} files is saved immediately before the program
+exits.  For each source file compiled with @option{-fprofile-arcs}, the profiling
+code first attempts to read in an existing @file{.da} file; if the file
+doesn't match the executable (differing number of basic block counts) it
+will ignore the contents of the file.  It then adds in the new execution
+counts and finally writes the data to the file.
+
+@node Gcov and Optimization
+@section Using @command{gcov} with GCC Optimization
+
+If you plan to use @command{gcov} to help optimize your code, you must
+first compile your program with two special GCC options:
+@samp{-fprofile-arcs -ftest-coverage}.  Aside from that, you can use any
+other GCC options; but if you want to prove that every single line
+in your program was executed, you should not compile with optimization
+at the same time.  On some machines the optimizer can eliminate some
+simple code lines by combining them with other lines.  For example, code
+like this:
+
+@smallexample
+if (a != b)
+  c = 1;
+else
+  c = 0;
+@end smallexample
+
+@noindent
+can be compiled into one instruction on some machines.  In this case,
+there is no way for @command{gcov} to calculate separate execution counts
+for each line because there isn't separate code for each line.  Hence
+the @command{gcov} output looks like this if you compiled the program with
+optimization:
+
+@smallexample
+      100  if (a != b)
+      100    c = 1;
+      100  else
+      100    c = 0;
+@end smallexample
+
+The output shows that this block of code, combined by optimization,
+executed 100 times.  In one sense this result is correct, because there
+was only one instruction representing all four of these lines.  However,
+the output does not indicate how many times the result was 0 and how
+many times the result was 1.
+@c man end
+
+@node Gcov Data Files
+@section Brief description of @command{gcov} data files
+
+@command{gcov} uses three files for doing profiling.  The names of these
+files are derived from the original @emph{source} file by substituting
+the file suffix with either @file{.bb}, @file{.bbg}, or @file{.da}.  All
+of these files are placed in the same directory as the source file, and
+contain data stored in a platform-independent method.
+
+The @file{.bb} and @file{.bbg} files are generated when the source file
+is compiled with the GCC @option{-ftest-coverage} option.  The
+@file{.bb} file contains a list of source files (including headers),
+functions within those files, and line numbers corresponding to each
+basic block in the source file.
+
+The @file{.bb} file format consists of several lists of 4-byte integers
+which correspond to the line numbers of each basic block in the
+file.  Each list is terminated by a line number of 0.  A line number of @minus{}1
+is used to designate that the source file name (padded to a 4-byte
+boundary and followed by another @minus{}1) follows.  In addition, a line number
+of @minus{}2 is used to designate that the name of a function (also padded to a
+4-byte boundary and followed by a @minus{}2) follows.
+
+The @file{.bbg} file is used to reconstruct the program flow graph for
+the source file.  It contains a list of the program flow arcs (possible
+branches taken from one basic block to another) for each function which,
+in combination with the @file{.bb} file, enables gcov to reconstruct the
+program flow.
+
+In the @file{.bbg} file, the format is:
+@smallexample
+        number of basic blocks for function #0 (4-byte number)
+        total number of arcs for function #0 (4-byte number)
+        count of arcs in basic block #0 (4-byte number)
+        destination basic block of arc #0 (4-byte number)
+        flag bits (4-byte number)
+        destination basic block of arc #1 (4-byte number)
+        flag bits (4-byte number)
+        @dots{}
+        destination basic block of arc #N (4-byte number)
+        flag bits (4-byte number)
+        count of arcs in basic block #1 (4-byte number)
+        destination basic block of arc #0 (4-byte number)
+        flag bits (4-byte number)
+        @dots{}
+@end smallexample
+
+A @minus{}1 (stored as a 4-byte number) is used to separate each function's
+list of basic blocks, and to verify that the file has been read
+correctly.
+
+The @file{.da} file is generated when a program containing object files
+built with the GCC @option{-fprofile-arcs} option is executed.  A
+separate @file{.da} file is created for each source file compiled with
+this option, and the name of the @file{.da} file is stored as an
+absolute pathname in the resulting object file.  This path name is
+derived from the source file name by substituting a @file{.da} suffix.
+
+The format of the @file{.da} file is fairly simple.  The first 8-byte
+number is the number of counts in the file, followed by the counts
+(stored as 8-byte numbers).  Each count corresponds to the number of
+times each arc in the program is executed.  The counts are cumulative;
+each time the program is executed, it attempts to combine the existing
+@file{.da} files with the new counts for this invocation of the
+program.  It ignores the contents of any @file{.da} files whose number of
+arcs doesn't correspond to the current program, and merely overwrites
+them instead.
+
+All three of these files use the functions in @file{gcov-io.h} to store
+integers; the functions in this header provide a machine-independent
+mechanism for storing and retrieving data from a stream.
+
diff --git a/contrib/gcc/doc/gnu.texi b/contrib/gcc/doc/gnu.texi
new file mode 100644
index 0000000..641fe30
--- /dev/null
+++ b/contrib/gcc/doc/gnu.texi
@@ -0,0 +1,20 @@
+@c Copyright (C) 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node GNU Project
+@unnumbered The GNU Project and GNU/Linux
+
+The GNU Project was launched in 1984 to develop a complete Unix-like
+operating system which is free software: the GNU system.  (GNU is a
+recursive acronym for ``GNU's Not Unix''; it is pronounced
+``guh-NEW''@.)  Variants of the GNU operating system, which use the
+kernel Linux, are now widely used; though these systems are often
+referred to as ``Linux'', they are more accurately called GNU/Linux
+systems.
+
+For more information, see:
+@smallexample
+@uref{http://www.gnu.org/}
+@uref{http://www.gnu.org/gnu/linux-and-gnu.html}
+@end smallexample
diff --git a/contrib/gcc/doc/headerdirs.texi b/contrib/gcc/doc/headerdirs.texi
new file mode 100644
index 0000000..17db57f
--- /dev/null
+++ b/contrib/gcc/doc/headerdirs.texi
@@ -0,0 +1,33 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Header Dirs
+@chapter Standard Header File Directories
+
+@code{GCC_INCLUDE_DIR} means the same thing for native and cross.  It is
+where GNU CC stores its private include files, and also where GNU CC
+stores the fixed include files.  A cross compiled GNU CC runs
+@code{fixincludes} on the header files in @file{$(tooldir)/include}.
+(If the cross compilation header files need to be fixed, they must be
+installed before GNU CC is built.  If the cross compilation header files
+are already suitable for ISO C and GNU CC, nothing special need be
+done).
+
+@code{GPLUSPLUS_INCLUDE_DIR} means the same thing for native and cross.  It
+is where @code{g++} looks first for header files.  The C++ library
+installs only target independent header files in that directory.
+
+@code{LOCAL_INCLUDE_DIR} is used only by native compilers.  GNU CC
+doesn't install anything there.  It is normally
+@file{/usr/local/include}.  This is where local additions to a packaged
+system should place header files.
+
+@code{CROSS_INCLUDE_DIR} is used only by cross compilers.  GNU CC
+doesn't install anything there.
+
+@code{TOOL_INCLUDE_DIR} is used for both native and cross compilers.  It
+is the place for other packages to install header files that GNU CC will
+use.  For a cross-compiler, this is the equivalent of
+@file{/usr/include}.  When you build a cross-compiler,
+@code{fixincludes} processes any header files in this directory.
diff --git a/contrib/gcc/doc/hostconfig.texi b/contrib/gcc/doc/hostconfig.texi
new file mode 100644
index 0000000..33c0a3b
--- /dev/null
+++ b/contrib/gcc/doc/hostconfig.texi
@@ -0,0 +1,130 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+@c 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Host Config
+@chapter Host Configuration Headers
+@cindex configuration file
+@cindex @file{xm-@var{machine}.h}
+
+Host configuration headers contain macro definitions that describe the
+machine and system on which the compiler is running.  They are usually
+unnecessary.  Most of the things GCC needs to know about the host
+system can be deduced by the @command{configure} script.
+
+If your host does need a special configuration header, it should be
+named @file{xm-@var{machine}.h}, where @var{machine} is a short mnemonic
+for the machine.  Here are some macros which this header can define.
+
+@ftable @code
+@item VMS
+Define this macro if the host system is VMS@.
+
+@item FATAL_EXIT_CODE
+A C expression for the status code to be returned when the compiler
+exits after serious errors.  The default is the system-provided macro
+@samp{EXIT_FAILURE}, or @samp{1} if the system doesn't define that
+macro.  Define this macro only if these defaults are incorrect.
+
+@item SUCCESS_EXIT_CODE
+A C expression for the status code to be returned when the compiler
+exits without serious errors.  (Warnings are not serious errors.)  The
+default is the system-provided macro @samp{EXIT_SUCCESS}, or @samp{0} if
+the system doesn't define that macro.  Define this macro only if these
+defaults are incorrect.
+
+@item USE_C_ALLOCA
+Define this macro if GCC should use the C implementation of @code{alloca}
+provided by @file{libiberty.a}.  This only affects how some parts of the
+compiler itself allocate memory.  It does not change code generation.
+
+When GCC is built with a compiler other than itself, the C @code{alloca}
+is always used.  This is because most other implementations have serious
+bugs.  You should define this macro only on a system where no
+stack-based @code{alloca} can possibly work.  For instance, if a system
+has a small limit on the size of the stack, GCC's builtin @code{alloca}
+will not work reliably.
+
+@item HAVE_DOS_BASED_FILE_SYSTEM
+Define this macro if the host file system obeys the semantics defined by
+MS-DOS instead of Unix.  DOS file systems are case insensitive, file
+specifications may begin with a drive letter, and both forward slash and
+backslash (@samp{/} and @samp{\}) are directory separators.  If you
+define this macro, you probably need to define the next three macros too.
+
+@item PATH_SEPARATOR
+If defined, this macro should expand to a character constant specifying
+the separator for elements of search paths.  The default value is a
+colon (@samp{:}).  DOS-based systems usually use semicolon (@samp{;}).
+
+@item DIR_SEPARATOR
+@itemx DIR_SEPARATOR_2
+If defined, these macros expand to character constants specifying
+separators for directory names within a file specification.  They are
+used somewhat inconsistently throughout the compiler.  If your system
+behaves like Unix (only forward slash separates pathnames), define
+neither of them.  If your system behaves like DOS (both forward and
+backward slash can be used), define @code{DIR_SEPARATOR} to @samp{/}
+and @code{DIR_SEPARATOR_2} to @samp{\}.
+
+@item HOST_OBJECT_SUFFIX
+Define this macro to be a C string representing the suffix for object
+files on your host machine.  If you do not define this macro, GCC will
+use @samp{.o} as the suffix for object files.
+
+@item HOST_EXECUTABLE_SUFFIX
+Define this macro to be a C string representing the suffix for
+executable files on your host machine.  If you do not define this macro,
+GCC will use the null string as the suffix for executable files.
+
+@item HOST_BIT_BUCKET
+A pathname defined by the host operating system, which can be opened as
+a file and written to, but all the information written is discarded.
+This is commonly known as a @dfn{bit bucket} or @dfn{null device}.  If
+you do not define this macro, GCC will use @samp{/dev/null} as the bit
+bucket.  If the host does not support a bit bucket, define this macro to
+an invalid filename.
+
+@item COLLECT2_HOST_INITIALIZATION
+If defined, a C statement (sans semicolon) that performs host-dependent
+initialization when @code{collect2} is being initialized.
+
+@item GCC_DRIVER_HOST_INITIALIZATION
+If defined, a C statement (sans semicolon) that performs host-dependent
+initialization when a compilation driver is being initialized.
+
+@item UPDATE_PATH_HOST_CANONICALIZE (@var{path})
+If defined, a C statement (sans semicolon) that performs host-dependent
+canonicalization when a path used in a compilation driver or
+preprocessor is canonicalized.  @var{path} is a malloc-ed path to be
+canonicalized.  If the C statement does canonicalize @var{path} into a
+different buffer, the old path should be freed and the new buffer should
+have been allocated with malloc.
+
+@item DUMPFILE_FORMAT
+Define this macro to be a C string representing the format to use for
+constructing the index part of debugging dump file names.  The resultant
+string must fit in fifteen bytes.  The full filename will be the
+concatenation of: the prefix of the assembler file name, the string
+resulting from applying this format to an index number, and a string
+unique to each dump file kind, e.g. @samp{rtl}.
+
+If you do not define this macro, GCC will use @samp{.%02d.}.  You should
+define this macro if using the default will create an invalid file name.
+
+@item SMALL_ARG_MAX
+Define this macro if the host system has a small limit on the total
+size of an argument vector.  This causes the driver to take more care
+not to pass unnecessary arguments to subprocesses.
+@end ftable
+
+In addition, if @command{configure} generates an incorrect definition of
+any of the macros in @file{auto-host.h}, you can override that
+definition in a host configuration header.  If you need to do this,
+first see if it is possible to fix @command{configure}.
+
+If you need to define only a few of these macros, and they have simple
+definitions, consider using the @code{xm_defines} variable in your
+@file{config.gcc} entry instead of creating a host configuration header.
+@xref{System Config}.
diff --git a/contrib/gcc/doc/include/fdl.texi b/contrib/gcc/doc/include/fdl.texi
new file mode 100644
index 0000000..1f3d8b652
--- /dev/null
+++ b/contrib/gcc/doc/include/fdl.texi
@@ -0,0 +1,434 @@
+@ignore
+@c Set file name and title for man page.
+@setfilename gfdl
+@settitle GNU Free Documentation License
+@c man begin SEEALSO
+gpl(7), fsf-funding(7).
+@c man end
+@c man begin COPYRIGHT
+Copyright @copyright{} 2000 Free Software Foundation, Inc.
+59 Temple Place, Suite 330, Boston, MA  02111-1307, USA
+
+Everyone is permitted to copy and distribute verbatim copies
+of this license document, but changing it is not allowed.
+@c man end
+@end ignore
+@c Special handling for inclusion in the install manual.
+@ifset gfdlhtml
+@ifnothtml
+@comment node-name,     next,          previous, up
+@node    GNU Free Documentation License, Concept Index, Old, Top
+@end ifnothtml
+@html
+<h1 align="center">Installing GCC: GNU Free Documentation License</h1>
+@end html
+@ifnothtml
+@unnumbered GNU Free Documentation License
+@end ifnothtml
+@end ifset
+@c man begin DESCRIPTION
+@ifclear gfdlhtml
+@node GNU Free Documentation License
+@unnumbered GNU Free Documentation License
+@end ifclear
+
+@cindex FDL, GNU Free Documentation License
+@center Version 1.1, March 2000
+
+@display
+Copyright @copyright{} 2000 Free Software Foundation, Inc.
+59 Temple Place, Suite 330, Boston, MA  02111-1307, USA
+
+Everyone is permitted to copy and distribute verbatim copies
+of this license document, but changing it is not allowed.
+@end display
+
+@enumerate 0
+@item
+PREAMBLE
+
+The purpose of this License is to make a manual, textbook, or other
+written document @dfn{free} in the sense of freedom: to assure everyone
+the effective freedom to copy and redistribute it, with or without
+modifying it, either commercially or noncommercially.  Secondarily,
+this License preserves for the author and publisher a way to get
+credit for their work, while not being considered responsible for
+modifications made by others.
+
+This License is a kind of ``copyleft'', which means that derivative
+works of the document must themselves be free in the same sense.  It
+complements the GNU General Public License, which is a copyleft
+license designed for free software.
+
+We have designed this License in order to use it for manuals for free
+software, because free software needs free documentation: a free
+program should come with manuals providing the same freedoms that the
+software does.  But this License is not limited to software manuals;
+it can be used for any textual work, regardless of subject matter or
+whether it is published as a printed book.  We recommend this License
+principally for works whose purpose is instruction or reference.
+
+@item
+APPLICABILITY AND DEFINITIONS
+
+This License applies to any manual or other work that contains a
+notice placed by the copyright holder saying it can be distributed
+under the terms of this License.  The ``Document'', below, refers to any
+such manual or work.  Any member of the public is a licensee, and is
+addressed as ``you''.
+
+A ``Modified Version'' of the Document means any work containing the
+Document or a portion of it, either copied verbatim, or with
+modifications and/or translated into another language.
+
+A ``Secondary Section'' is a named appendix or a front-matter section of
+the Document that deals exclusively with the relationship of the
+publishers or authors of the Document to the Document's overall subject
+(or to related matters) and contains nothing that could fall directly
+within that overall subject.  (For example, if the Document is in part a
+textbook of mathematics, a Secondary Section may not explain any
+mathematics.)  The relationship could be a matter of historical
+connection with the subject or with related matters, or of legal,
+commercial, philosophical, ethical or political position regarding
+them.
+
+The ``Invariant Sections'' are certain Secondary Sections whose titles
+are designated, as being those of Invariant Sections, in the notice
+that says that the Document is released under this License.
+
+The ``Cover Texts'' are certain short passages of text that are listed,
+as Front-Cover Texts or Back-Cover Texts, in the notice that says that
+the Document is released under this License.
+
+A ``Transparent'' copy of the Document means a machine-readable copy,
+represented in a format whose specification is available to the
+general public, whose contents can be viewed and edited directly and
+straightforwardly with generic text editors or (for images composed of
+pixels) generic paint programs or (for drawings) some widely available
+drawing editor, and that is suitable for input to text formatters or
+for automatic translation to a variety of formats suitable for input
+to text formatters.  A copy made in an otherwise Transparent file
+format whose markup has been designed to thwart or discourage
+subsequent modification by readers is not Transparent.  A copy that is
+not ``Transparent'' is called ``Opaque''.
+
+Examples of suitable formats for Transparent copies include plain
+@sc{ascii} without markup, Texinfo input format, La@TeX{} input format,
+@acronym{SGML} or @acronym{XML} using a publicly available
+@acronym{DTD}, and standard-conforming simple @acronym{HTML} designed
+for human modification.  Opaque formats include PostScript,
+@acronym{PDF}, proprietary formats that can be read and edited only by
+proprietary word processors, @acronym{SGML} or @acronym{XML} for which
+the @acronym{DTD} and/or processing tools are not generally available,
+and the machine-generated @acronym{HTML} produced by some word
+processors for output purposes only.
+
+The ``Title Page'' means, for a printed book, the title page itself,
+plus such following pages as are needed to hold, legibly, the material
+this License requires to appear in the title page.  For works in
+formats which do not have any title page as such, ``Title Page'' means
+the text near the most prominent appearance of the work's title,
+preceding the beginning of the body of the text.
+
+@item
+VERBATIM COPYING
+
+You may copy and distribute the Document in any medium, either
+commercially or noncommercially, provided that this License, the
+copyright notices, and the license notice saying this License applies
+to the Document are reproduced in all copies, and that you add no other
+conditions whatsoever to those of this License.  You may not use
+technical measures to obstruct or control the reading or further
+copying of the copies you make or distribute.  However, you may accept
+compensation in exchange for copies.  If you distribute a large enough
+number of copies you must also follow the conditions in section 3.
+
+You may also lend copies, under the same conditions stated above, and
+you may publicly display copies.
+
+@item
+COPYING IN QUANTITY
+
+If you publish printed copies of the Document numbering more than 100,
+and the Document's license notice requires Cover Texts, you must enclose
+the copies in covers that carry, clearly and legibly, all these Cover
+Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
+the back cover.  Both covers must also clearly and legibly identify
+you as the publisher of these copies.  The front cover must present
+the full title with all words of the title equally prominent and
+visible.  You may add other material on the covers in addition.
+Copying with changes limited to the covers, as long as they preserve
+the title of the Document and satisfy these conditions, can be treated
+as verbatim copying in other respects.
+
+If the required texts for either cover are too voluminous to fit
+legibly, you should put the first ones listed (as many as fit
+reasonably) on the actual cover, and continue the rest onto adjacent
+pages.
+
+If you publish or distribute Opaque copies of the Document numbering
+more than 100, you must either include a machine-readable Transparent
+copy along with each Opaque copy, or state in or with each Opaque copy
+a publicly-accessible computer-network location containing a complete
+Transparent copy of the Document, free of added material, which the
+general network-using public has access to download anonymously at no
+charge using public-standard network protocols.  If you use the latter
+option, you must take reasonably prudent steps, when you begin
+distribution of Opaque copies in quantity, to ensure that this
+Transparent copy will remain thus accessible at the stated location
+until at least one year after the last time you distribute an Opaque
+copy (directly or through your agents or retailers) of that edition to
+the public.
+
+It is requested, but not required, that you contact the authors of the
+Document well before redistributing any large number of copies, to give
+them a chance to provide you with an updated version of the Document.
+
+@item
+MODIFICATIONS
+
+You may copy and distribute a Modified Version of the Document under
+the conditions of sections 2 and 3 above, provided that you release
+the Modified Version under precisely this License, with the Modified
+Version filling the role of the Document, thus licensing distribution
+and modification of the Modified Version to whoever possesses a copy
+of it.  In addition, you must do these things in the Modified Version:
+
+@enumerate A
+@item
+Use in the Title Page (and on the covers, if any) a title distinct
+from that of the Document, and from those of previous versions
+(which should, if there were any, be listed in the History section
+of the Document).  You may use the same title as a previous version
+if the original publisher of that version gives permission.
+
+@item
+List on the Title Page, as authors, one or more persons or entities
+responsible for authorship of the modifications in the Modified
+Version, together with at least five of the principal authors of the
+Document (all of its principal authors, if it has less than five).
+
+@item
+State on the Title page the name of the publisher of the
+Modified Version, as the publisher.
+
+@item
+Preserve all the copyright notices of the Document.
+
+@item
+Add an appropriate copyright notice for your modifications
+adjacent to the other copyright notices.
+
+@item
+Include, immediately after the copyright notices, a license notice
+giving the public permission to use the Modified Version under the
+terms of this License, in the form shown in the Addendum below.
+
+@item
+Preserve in that license notice the full lists of Invariant Sections
+and required Cover Texts given in the Document's license notice.
+
+@item
+Include an unaltered copy of this License.
+
+@item
+Preserve the section entitled ``History'', and its title, and add to
+it an item stating at least the title, year, new authors, and
+publisher of the Modified Version as given on the Title Page.  If
+there is no section entitled ``History'' in the Document, create one
+stating the title, year, authors, and publisher of the Document as
+given on its Title Page, then add an item describing the Modified
+Version as stated in the previous sentence.
+
+@item
+Preserve the network location, if any, given in the Document for
+public access to a Transparent copy of the Document, and likewise
+the network locations given in the Document for previous versions
+it was based on.  These may be placed in the ``History'' section.
+You may omit a network location for a work that was published at
+least four years before the Document itself, or if the original
+publisher of the version it refers to gives permission.
+
+@item
+In any section entitled ``Acknowledgments'' or ``Dedications'',
+preserve the section's title, and preserve in the section all the
+substance and tone of each of the contributor acknowledgments
+and/or dedications given therein.
+
+@item
+Preserve all the Invariant Sections of the Document,
+unaltered in their text and in their titles.  Section numbers
+or the equivalent are not considered part of the section titles.
+
+@item
+Delete any section entitled ``Endorsements''.  Such a section
+may not be included in the Modified Version.
+
+@item
+Do not retitle any existing section as ``Endorsements''
+or to conflict in title with any Invariant Section.
+@end enumerate
+
+If the Modified Version includes new front-matter sections or
+appendices that qualify as Secondary Sections and contain no material
+copied from the Document, you may at your option designate some or all
+of these sections as invariant.  To do this, add their titles to the
+list of Invariant Sections in the Modified Version's license notice.
+These titles must be distinct from any other section titles.
+
+You may add a section entitled ``Endorsements'', provided it contains
+nothing but endorsements of your Modified Version by various
+parties---for example, statements of peer review or that the text has
+been approved by an organization as the authoritative definition of a
+standard.
+
+You may add a passage of up to five words as a Front-Cover Text, and a
+passage of up to 25 words as a Back-Cover Text, to the end of the list
+of Cover Texts in the Modified Version.  Only one passage of
+Front-Cover Text and one of Back-Cover Text may be added by (or
+through arrangements made by) any one entity.  If the Document already
+includes a cover text for the same cover, previously added by you or
+by arrangement made by the same entity you are acting on behalf of,
+you may not add another; but you may replace the old one, on explicit
+permission from the previous publisher that added the old one.
+
+The author(s) and publisher(s) of the Document do not by this License
+give permission to use their names for publicity for or to assert or
+imply endorsement of any Modified Version.
+
+@item
+COMBINING DOCUMENTS
+
+You may combine the Document with other documents released under this
+License, under the terms defined in section 4 above for modified
+versions, provided that you include in the combination all of the
+Invariant Sections of all of the original documents, unmodified, and
+list them all as Invariant Sections of your combined work in its
+license notice.
+
+The combined work need only contain one copy of this License, and
+multiple identical Invariant Sections may be replaced with a single
+copy.  If there are multiple Invariant Sections with the same name but
+different contents, make the title of each such section unique by
+adding at the end of it, in parentheses, the name of the original
+author or publisher of that section if known, or else a unique number.
+Make the same adjustment to the section titles in the list of
+Invariant Sections in the license notice of the combined work.
+
+In the combination, you must combine any sections entitled ``History''
+in the various original documents, forming one section entitled
+``History''; likewise combine any sections entitled ``Acknowledgments'',
+and any sections entitled ``Dedications''.  You must delete all sections
+entitled ``Endorsements.''
+
+@item
+COLLECTIONS OF DOCUMENTS
+
+You may make a collection consisting of the Document and other documents
+released under this License, and replace the individual copies of this
+License in the various documents with a single copy that is included in
+the collection, provided that you follow the rules of this License for
+verbatim copying of each of the documents in all other respects.
+
+You may extract a single document from such a collection, and distribute
+it individually under this License, provided you insert a copy of this
+License into the extracted document, and follow this License in all
+other respects regarding verbatim copying of that document.
+
+@item
+AGGREGATION WITH INDEPENDENT WORKS
+
+A compilation of the Document or its derivatives with other separate
+and independent documents or works, in or on a volume of a storage or
+distribution medium, does not as a whole count as a Modified Version
+of the Document, provided no compilation copyright is claimed for the
+compilation.  Such a compilation is called an ``aggregate'', and this
+License does not apply to the other self-contained works thus compiled
+with the Document, on account of their being thus compiled, if they
+are not themselves derivative works of the Document.
+
+If the Cover Text requirement of section 3 is applicable to these
+copies of the Document, then if the Document is less than one quarter
+of the entire aggregate, the Document's Cover Texts may be placed on
+covers that surround only the Document within the aggregate.
+Otherwise they must appear on covers around the whole aggregate.
+
+@item
+TRANSLATION
+
+Translation is considered a kind of modification, so you may
+distribute translations of the Document under the terms of section 4.
+Replacing Invariant Sections with translations requires special
+permission from their copyright holders, but you may include
+translations of some or all Invariant Sections in addition to the
+original versions of these Invariant Sections.  You may include a
+translation of this License provided that you also include the
+original English version of this License.  In case of a disagreement
+between the translation and the original English version of this
+License, the original English version will prevail.
+
+@item
+TERMINATION
+
+You may not copy, modify, sublicense, or distribute the Document except
+as expressly provided for under this License.  Any other attempt to
+copy, modify, sublicense or distribute the Document is void, and will
+automatically terminate your rights under this License.  However,
+parties who have received copies, or rights, from you under this
+License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+@item
+FUTURE REVISIONS OF THIS LICENSE
+
+The Free Software Foundation may publish new, revised versions
+of the GNU Free Documentation License from time to time.  Such new
+versions will be similar in spirit to the present version, but may
+differ in detail to address new problems or concerns.  See
+@uref{http://www.gnu.org/copyleft/}.
+
+Each version of the License is given a distinguishing version number.
+If the Document specifies that a particular numbered version of this
+License ``or any later version'' applies to it, you have the option of
+following the terms and conditions either of that specified version or
+of any later version that has been published (not as a draft) by the
+Free Software Foundation.  If the Document does not specify a version
+number of this License, you may choose any version ever published (not
+as a draft) by the Free Software Foundation.
+@end enumerate
+
+@page
+@unnumberedsec ADDENDUM: How to use this License for your documents
+
+To use this License in a document you have written, include a copy of
+the License in the document and put the following copyright and
+license notices just after the title page:
+
+@smallexample
+@group
+  Copyright (C)  @var{year}  @var{your name}.
+  Permission is granted to copy, distribute and/or modify this document
+  under the terms of the GNU Free Documentation License, Version 1.1
+  or any later version published by the Free Software Foundation;
+  with the Invariant Sections being @var{list their titles}, with the
+  Front-Cover Texts being @var{list}, and with the Back-Cover Texts being @var{list}.
+  A copy of the license is included in the section entitled ``GNU
+  Free Documentation License''.
+@end group
+@end smallexample
+
+If you have no Invariant Sections, write ``with no Invariant Sections''
+instead of saying which ones are invariant.  If you have no
+Front-Cover Texts, write ``no Front-Cover Texts'' instead of
+``Front-Cover Texts being @var{list}''; likewise for Back-Cover Texts.
+
+If your document contains nontrivial examples of program code, we
+recommend releasing these examples in parallel under your choice of
+free software license, such as the GNU General Public License,
+to permit their use in free software.
+
+@c Local Variables:
+@c ispell-local-pdict: "ispell-dict"
+@c End:
+
+@c man end
diff --git a/contrib/gcc/doc/include/funding.texi b/contrib/gcc/doc/include/funding.texi
new file mode 100644
index 0000000..d1583fa
--- /dev/null
+++ b/contrib/gcc/doc/include/funding.texi
@@ -0,0 +1,60 @@
+@ignore
+@c Set file name and title for man page.
+@setfilename fsf-funding
+@settitle Funding Free Software
+@c man begin SEEALSO
+gpl(7), gfdl(7).
+@c man end
+@end ignore
+@node Funding
+@c man begin DESCRIPTION
+@unnumbered Funding Free Software
+
+If you want to have more free software a few years from now, it makes
+sense for you to help encourage people to contribute funds for its
+development.  The most effective approach known is to encourage
+commercial redistributors to donate.
+
+Users of free software systems can boost the pace of development by
+encouraging for-a-fee distributors to donate part of their selling price
+to free software developers---the Free Software Foundation, and others.
+
+The way to convince distributors to do this is to demand it and expect
+it from them.  So when you compare distributors, judge them partly by
+how much they give to free software development.  Show distributors
+they must compete to be the one who gives the most.
+
+To make this approach work, you must insist on numbers that you can
+compare, such as, ``We will donate ten dollars to the Frobnitz project
+for each disk sold.''  Don't be satisfied with a vague promise, such as
+``A portion of the profits are donated,'' since it doesn't give a basis
+for comparison.
+
+Even a precise fraction ``of the profits from this disk'' is not very
+meaningful, since creative accounting and unrelated business decisions
+can greatly alter what fraction of the sales price counts as profit.
+If the price you pay is $50, ten percent of the profit is probably
+less than a dollar; it might be a few cents, or nothing at all.
+
+Some redistributors do development work themselves.  This is useful too;
+but to keep everyone honest, you need to inquire how much they do, and
+what kind.  Some kinds of development make much more long-term
+difference than others.  For example, maintaining a separate version of
+a program contributes very little; maintaining the standard version of a
+program for the whole community contributes much.  Easy new ports
+contribute little, since someone else would surely do them; difficult
+ports such as adding a new CPU to the GNU Compiler Collection contribute more;
+major new features or packages contribute the most.
+
+By establishing the idea that supporting further development is ``the
+proper thing to do'' when distributing free software for a fee, we can
+assure a steady flow of resources into making more free software.
+@c man end
+
+@display
+@c man begin COPYRIGHT
+Copyright @copyright{} 1994 Free Software Foundation, Inc.
+Verbatim copying and redistribution of this section is permitted
+without royalty; alteration is not permitted.
+@c man end
+@end display
diff --git a/contrib/gcc/doc/include/gcc-common.texi b/contrib/gcc/doc/include/gcc-common.texi
new file mode 100644
index 0000000..947dde1
--- /dev/null
+++ b/contrib/gcc/doc/include/gcc-common.texi
@@ -0,0 +1,36 @@
+@c Copyright (C) 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@c Common values used in the GCC manuals:
+
+@set version-GCC 3.1
+
+@c Common macros to support generating man pages:
+
+@macro gcctabopt{body}
+@code{\body\}
+@end macro
+@macro gccoptlist{body}
+@smallexample
+\body\
+@end smallexample
+@end macro
+@c Makeinfo handles the above macro OK, TeX needs manual line breaks;
+@c they get lost at some point in handling the macro.  But if @macro is
+@c used here rather than @alias, it produces double line breaks.
+@iftex
+@alias gol = *
+@end iftex
+@ifnottex
+@macro gol
+@end macro
+@end ifnottex
+
+@c For FSF printing, define FSFPRINT.  Also update the ISBNs and last
+@c printing dates in gcc.texi and gccint.texi.
+@c @set FSFPRINT
+@ifset FSFPRINT
+@smallbook
+@finalout
+@end ifset
diff --git a/contrib/gcc/doc/include/gpl.texi b/contrib/gcc/doc/include/gpl.texi
new file mode 100644
index 0000000..4304b72
--- /dev/null
+++ b/contrib/gcc/doc/include/gpl.texi
@@ -0,0 +1,409 @@
+@ignore
+@c Set file name and title for man page.
+@setfilename gpl
+@settitle GNU General Public License
+@c man begin SEEALSO
+gfdl(7), fsf-funding(7).
+@c man end
+@c man begin COPYRIGHT
+Copyright @copyright{} 1989, 1991 Free Software Foundation, Inc.
+59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+
+Everyone is permitted to copy and distribute verbatim copies
+of this license document, but changing it is not allowed.
+@c man end
+@end ignore
+@node Copying
+@c man begin DESCRIPTION
+@unnumbered GNU GENERAL PUBLIC LICENSE
+@center Version 2, June 1991
+
+@display
+Copyright @copyright{} 1989, 1991 Free Software Foundation, Inc.
+59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+
+Everyone is permitted to copy and distribute verbatim copies
+of this license document, but changing it is not allowed.
+@end display
+
+@unnumberedsec Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software---to make sure the software is free for all its users.  This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it.  (Some other Free Software Foundation software is covered by
+the GNU Library General Public License instead.)  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+  To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have.  You must make sure that they, too, receive or can get the
+source code.  And you must show them these terms so they know their
+rights.
+
+  We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+  Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software.  If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
+that any problems introduced by others will not reflect on the original
+authors' reputations.
+
+  Finally, any free program is threatened constantly by software
+patents.  We wish to avoid the danger that redistributors of a free
+program will individually obtain patent licenses, in effect making the
+program proprietary.  To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+@iftex
+@unnumberedsec TERMS AND CONDITIONS FOR COPYING,@*DISTRIBUTION AND MODIFICATION
+@end iftex
+@ifnottex
+@center TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+@end ifnottex
+
+@enumerate 0
+@item
+This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License.  The ``Program'', below,
+refers to any such program or work, and a ``work based on the Program''
+means either the Program or any derivative work under copyright law:
+that is to say, a work containing the Program or a portion of it,
+either verbatim or with modifications and/or translated into another
+language.  (Hereinafter, translation is included without limitation in
+the term ``modification''.)  Each licensee is addressed as ``you''.
+
+Activities other than copying, distribution and modification are not
+covered by this License; they are outside its scope.  The act of
+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
+
+@item
+You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; keep intact all the
+notices that refer to this License and to the absence of any warranty;
+and give any other recipients of the Program a copy of this License
+along with the Program.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
+
+@item
+You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+
+@enumerate a
+@item
+You must cause the modified files to carry prominent notices
+stating that you changed the files and the date of any change.
+
+@item
+You must cause any work that you distribute or publish, that in
+whole or in part contains or is derived from the Program or any
+part thereof, to be licensed as a whole at no charge to all third
+parties under the terms of this License.
+
+@item
+If the modified program normally reads commands interactively
+when run, you must cause it, when started running for such
+interactive use in the most ordinary way, to print or display an
+announcement including an appropriate copyright notice and a
+notice that there is no warranty (or else, saying that you provide
+a warranty) and that users may redistribute the program under
+these conditions, and telling the user how to view a copy of this
+License.  (Exception: if the Program itself is interactive but
+does not normally print such an announcement, your work based on
+the Program is not required to print an announcement.)
+@end enumerate
+
+These requirements apply to the modified work as a whole.  If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
+themselves, then this License, and its terms, do not apply to those
+sections when you distribute them as separate works.  But when you
+distribute the same sections as part of a whole which is a work based
+on the Program, the distribution of the whole must be on the terms of
+this License, whose permissions for other licensees extend to the
+entire whole, and thus to each and every part regardless of who wrote it.
+
+Thus, it is not the intent of this section to claim rights or contest
+your rights to work written entirely by you; rather, the intent is to
+exercise the right to control the distribution of derivative or
+collective works based on the Program.
+
+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
+the scope of this License.
+
+@item
+You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
+
+@enumerate a
+@item
+Accompany it with the complete corresponding machine-readable
+source code, which must be distributed under the terms of Sections
+1 and 2 above on a medium customarily used for software interchange; or,
+
+@item
+Accompany it with a written offer, valid for at least three
+years, to give any third party, for a charge no more than your
+cost of physically performing source distribution, a complete
+machine-readable copy of the corresponding source code, to be
+distributed under the terms of Sections 1 and 2 above on a medium
+customarily used for software interchange; or,
+
+@item
+Accompany it with the information you received as to the offer
+to distribute corresponding source code.  (This alternative is
+allowed only for noncommercial distribution and only if you
+received the program in object code or executable form with such
+an offer, in accord with Subsection b above.)
+@end enumerate
+
+The source code for a work means the preferred form of the work for
+making modifications to it.  For an executable work, complete source
+code means all the source code for all modules it contains, plus any
+associated interface definition files, plus the scripts used to
+control compilation and installation of the executable.  However, as a
+special exception, the source code distributed need not include
+anything that is normally distributed (in either source or binary
+form) with the major components (compiler, kernel, and so on) of the
+operating system on which the executable runs, unless that component
+itself accompanies the executable.
+
+If distribution of executable or object code is made by offering
+access to copy from a designated place, then offering equivalent
+access to copy the source code from the same place counts as
+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
+
+@item
+You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License.  Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+@item
+You are not required to accept this License, since you have not
+signed it.  However, nothing else grants you permission to modify or
+distribute the Program or its derivative works.  These actions are
+prohibited by law if you do not accept this License.  Therefore, by
+modifying or distributing the Program (or any work based on the
+Program), you indicate your acceptance of this License to do so, and
+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
+
+@item
+Each time you redistribute the Program (or any work based on the
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
+these terms and conditions.  You may not impose any further
+restrictions on the recipients' exercise of the rights granted herein.
+You are not responsible for enforcing compliance by third parties to
+this License.
+
+@item
+If, as a consequence of a court judgment or allegation of patent
+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot
+distribute so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all.  For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
+apply and the section as a whole is intended to apply in other
+circumstances.
+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
+such claims; this section has the sole purpose of protecting the
+integrity of the free software distribution system, which is
+implemented by public license practices.  Many people have made
+generous contributions to the wide range of software distributed
+through that system in reliance on consistent application of that
+system; it is up to the author/donor to decide if he or she is willing
+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+@item
+If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded.  In such case, this License incorporates
+the limitation as if written in the body of this License.
+
+@item
+The Free Software Foundation may publish revised and/or new versions
+of the General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+Each version is given a distinguishing version number.  If the Program
+specifies a version number of this License which applies to it and ``any
+later version'', you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation.  If the Program does not specify a version number of
+this License, you may choose any version ever published by the Free Software
+Foundation.
+
+@item
+If you wish to incorporate parts of the Program into other free
+programs whose distribution conditions are different, write to the author
+to ask for permission.  For software which is copyrighted by the Free
+Software Foundation, write to the Free Software Foundation; we sometimes
+make exceptions for this.  Our decision will be guided by the two goals
+of preserving the free status of all derivatives of our free software and
+of promoting the sharing and reuse of software generally.
+
+@iftex
+@heading NO WARRANTY
+@end iftex
+@ifnottex
+@center NO WARRANTY
+@end ifnottex
+
+@item
+BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
+PROVIDE THE PROGRAM ``AS IS'' WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
+OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
+TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
+PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
+REPAIR OR CORRECTION.
+
+@item
+IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+@end enumerate
+
+@iftex
+@heading END OF TERMS AND CONDITIONS
+@end iftex
+@ifnottex
+@center END OF TERMS AND CONDITIONS
+@end ifnottex
+
+@page
+@unnumberedsec How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the ``copyright'' line and a pointer to where the full notice is found.
+
+@smallexample
+@var{one line to give the program's name and a brief idea of what it does.}
+Copyright (C) @var{year}  @var{name of author}
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.
+@end smallexample
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+@smallexample
+Gnomovision version 69, Copyright (C) @var{year} @var{name of author}
+Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
+type `show w'.
+This is free software, and you are welcome to redistribute it
+under certain conditions; type `show c' for details.
+@end smallexample
+
+The hypothetical commands @samp{show w} and @samp{show c} should show
+the appropriate parts of the General Public License.  Of course, the
+commands you use may be called something other than @samp{show w} and
+@samp{show c}; they could even be mouse-clicks or menu items---whatever
+suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a ``copyright disclaimer'' for the program, if
+necessary.  Here is a sample; alter the names:
+
+@smallexample
+Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+`Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+@var{signature of Ty Coon}, 1 April 1989
+Ty Coon, President of Vice
+@end smallexample
+
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Library General
+Public License instead of this License.
+@c man end
diff --git a/contrib/gcc/doc/install-old.texi b/contrib/gcc/doc/install-old.texi
new file mode 100644
index 0000000..9ce9896
--- /dev/null
+++ b/contrib/gcc/doc/install-old.texi
@@ -0,0 +1,725 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file install.texi.
+
+@ifnothtml
+@comment node-name,     next,          previous, up
+@node    Old, GNU Free Documentation License, Specific, Top
+@end ifnothtml
+@html
+<h1 align="center">Old installation documentation</h1>
+@end html
+@ifnothtml
+@chapter Old installation documentation
+@end ifnothtml
+
+Note most of this information is out of date and superseded by the
+previous chapters of this manual.  It is provided for historical
+reference only, because of a lack of volunteers to merge it into the
+main manual.
+
+@ifnothtml
+@menu
+* Configurations::    Configurations Supported by GNU CC.
+* Cross-Compiler::   Building and installing a cross-compiler.
+* VMS Install::   See below for installation on VMS.
+@end menu
+@end ifnothtml
+
+Here is the procedure for installing GNU CC on a GNU or Unix system.
+See @ref{VMS Install}, for VMS systems.
+
+@enumerate
+@item
+If you have chosen a configuration for GNU CC which requires other GNU
+tools (such as GAS or the GNU linker) instead of the standard system
+tools, install the required tools in the build directory under the names
+@file{as}, @file{ld} or whatever is appropriate.  This will enable the
+compiler to find the proper tools for compilation of the program
+@file{enquire}.
+
+Alternatively, you can do subsequent compilation using a value of the
+@code{PATH} environment variable such that the necessary GNU tools come
+before the standard system tools.
+
+@item
+Specify the host, build and target machine configurations.  You do this
+when you run the @file{configure} script.
+
+The @dfn{build} machine is the system which you are using, the
+@dfn{host} machine is the system where you want to run the resulting
+compiler (normally the build machine), and the @dfn{target} machine is
+the system for which you want the compiler to generate code.
+
+If you are building a compiler to produce code for the machine it runs
+on (a native compiler), you normally do not need to specify any operands
+to @file{configure}; it will try to guess the type of machine you are on
+and use that as the build, host and target machines.  So you don't need
+to specify a configuration when building a native compiler unless
+@file{configure} cannot figure out what your configuration is or guesses
+wrong.
+
+In those cases, specify the build machine's @dfn{configuration name}
+with the @option{--host} option; the host and target will default to be
+the same as the host machine.  (If you are building a cross-compiler,
+see @ref{Cross-Compiler}.)
+
+Here is an example:
+
+@smallexample
+./configure --host=sparc-sun-sunos4.1
+@end smallexample
+
+A configuration name may be canonical or it may be more or less
+abbreviated.
+
+A canonical configuration name has three parts, separated by dashes.
+It looks like this: @samp{@var{cpu}-@var{company}-@var{system}}.
+(The three parts may themselves contain dashes; @file{configure}
+can figure out which dashes serve which purpose.)  For example,
+@samp{m68k-sun-sunos4.1} specifies a Sun 3.
+
+You can also replace parts of the configuration by nicknames or aliases.
+For example, @samp{sun3} stands for @samp{m68k-sun}, so
+@samp{sun3-sunos4.1} is another way to specify a Sun 3.
+
+You can specify a version number after any of the system types, and some
+of the CPU types.  In most cases, the version is irrelevant, and will be
+ignored.  So you might as well specify the version if you know it.
+
+See @ref{Configurations}, for a list of supported configuration names and
+notes on many of the configurations.  You should check the notes in that
+section before proceeding any further with the installation of GNU CC@.
+
+@end enumerate
+
+@ifnothtml
+@node Configurations, Cross-Compiler, , Old
+@section Configurations Supported by GNU CC
+@end ifnothtml
+@html
+<h2>@anchor{Configurations}Configurations Supported by GNU CC</h2>
+@end html
+@cindex configurations supported by GNU CC
+
+Here are the possible CPU types:
+
+@quotation
+@c gmicro, fx80, spur and tahoe omitted since they don't work.
+1750a, a29k, alpha, arm, avr, c@var{n}, clipper, dsp16xx, elxsi, fr30, h8300,
+hppa1.0, hppa1.1, i370, i386, i486, i586, i686, i786, i860, i960, m32r,
+m68000, m68k, m6811, m6812, m88k, mcore, mips, mipsel, mips64, mips64el,
+mn10200, mn10300, ns32k, pdp11, powerpc, powerpcle, romp, rs6000, sh, sparc,
+sparclite, sparc64, v850, vax, we32k.
+@end quotation
+
+Here are the recognized company names.  As you can see, customary
+abbreviations are used rather than the longer official names.
+
+@c What should be done about merlin, tek*, dolphin?
+@quotation
+acorn, alliant, altos, apollo, apple, att, bull,
+cbm, convergent, convex, crds, dec, dg, dolphin,
+elxsi, encore, harris, hitachi, hp, ibm, intergraph, isi,
+mips, motorola, ncr, next, ns, omron, plexus,
+sequent, sgi, sony, sun, tti, unicom, wrs.
+@end quotation
+
+The company name is meaningful only to disambiguate when the rest of
+the information supplied is insufficient.  You can omit it, writing
+just @samp{@var{cpu}-@var{system}}, if it is not needed.  For example,
+@samp{vax-ultrix4.2} is equivalent to @samp{vax-dec-ultrix4.2}.
+
+Here is a list of system types:
+
+@quotation
+386bsd, aix, acis, amigaos, aos, aout, aux, bosx, bsd, clix, coff, ctix, cxux,
+dgux, dynix, ebmon, ecoff, elf, esix, freebsd, hms, genix, gnu, linux,
+linux-gnu, hiux, hpux, iris, irix, isc, luna, lynxos, mach, minix, msdos, mvs,
+netbsd, newsos, nindy, ns, osf, osfrose, ptx, riscix, riscos, rtu, sco, sim,
+solaris, sunos, sym, sysv, udi, ultrix, unicos, uniplus, unos, vms, vsta,
+vxworks, winnt, xenix.
+@end quotation
+
+@noindent
+You can omit the system type; then @file{configure} guesses the
+operating system from the CPU and company.
+
+You can add a version number to the system type; this may or may not
+make a difference.  For example, you can write @samp{bsd4.3} or
+@samp{bsd4.4} to distinguish versions of BSD@.  In practice, the version
+number is most needed for @samp{sysv3} and @samp{sysv4}, which are often
+treated differently.
+
+@samp{linux-gnu} is the canonical name for the GNU/Linux target; however
+GNU CC will also accept @samp{linux}.  The version of the kernel in use is
+not relevant on these systems.  A suffix such as @samp{libc1} or @samp{aout}
+distinguishes major versions of the C library; all of the suffixed versions
+are obsolete.
+
+If you specify an impossible combination such as @samp{i860-dg-vms},
+then you may get an error message from @file{configure}, or it may
+ignore part of the information and do the best it can with the rest.
+@file{configure} always prints the canonical name for the alternative
+that it used.  GNU CC does not support all possible alternatives.
+
+Often a particular model of machine has a name.  Many machine names are
+recognized as aliases for CPU/company combinations.  Thus, the machine
+name @samp{sun3}, mentioned above, is an alias for @samp{m68k-sun}.
+Sometimes we accept a company name as a machine name, when the name is
+popularly used for a particular machine.  Here is a table of the known
+machine names:
+
+@quotation
+3300, 3b1, 3b@var{n}, 7300, altos3068, altos,
+apollo68, att-7300, balance,
+convex-c@var{n}, crds, decstation-3100,
+decstation, delta, encore,
+fx2800, gmicro, hp7@var{nn}, hp8@var{nn},
+hp9k2@var{nn}, hp9k3@var{nn}, hp9k7@var{nn},
+hp9k8@var{nn}, iris4d, iris, isi68,
+m3230, magnum, merlin, miniframe,
+mmax, news-3600, news800, news, next,
+pbd, pc532, pmax, powerpc, powerpcle, ps2, risc-news,
+rtpc, sun2, sun386i, sun386, sun3,
+sun4, symmetry, tower-32, tower.
+@end quotation
+
+@noindent
+Remember that a machine name specifies both the cpu type and the company
+name.
+If you want to install your own homemade configuration files, you can
+use @samp{local} as the company name to access them.  If you use
+configuration @samp{@var{cpu}-local}, the configuration name
+without the cpu prefix
+is used to form the configuration file names.
+
+Thus, if you specify @samp{m68k-local}, configuration uses
+files @file{m68k.md}, @file{local.h}, @file{m68k.c},
+@file{xm-local.h}, @file{t-local}, and @file{x-local}, all in the
+directory @file{config/m68k}.
+
+Here is a list of configurations that have special treatment or special
+things you must know:
+
+@table @samp
+@item vax-dec-vms
+See @ref{VMS Install}, for details on how to install GNU CC on VMS@.
+@end table
+
+@ifnothtml
+@node Cross-Compiler, VMS Install, Configurations, Old
+@section Building and Installing a Cross-Compiler
+@end ifnothtml
+@html
+<h2>@anchor{Cross-Compiler}Building and Installing a Cross-Compiler</h2>
+@end html
+@cindex cross-compiler, installation
+
+GNU CC can function as a cross-compiler for many machines, but not all.
+
+@itemize @bullet
+@item
+Cross-compilers for the Mips as target using the Mips assembler
+currently do not work, because the auxiliary programs
+@file{mips-tdump.c} and @file{mips-tfile.c} can't be compiled on
+anything but a Mips.  It does work to cross compile for a Mips
+if you use the GNU assembler and linker.
+
+@item
+Cross-compilers between machines with different floating point formats
+have not all been made to work.  GNU CC now has a floating point
+emulator with which these can work, but each target machine description
+needs to be updated to take advantage of it.
+
+@item
+Cross-compilation between machines of different word sizes is
+somewhat problematic and sometimes does not work.
+@end itemize
+
+Since GNU CC generates assembler code, you probably need a
+cross-assembler that GNU CC can run, in order to produce object files.
+If you want to link on other than the target machine, you need a
+cross-linker as well.  You also need header files and libraries suitable
+for the target machine that you can install on the host machine.
+
+@ifnothtml
+@menu
+* Steps of Cross::      Using a cross-compiler involves several steps
+                          that may be carried out on different machines.
+* Configure Cross::     Configuring a cross-compiler.
+* Tools and Libraries:: Where to put the linker and assembler, and the C library.
+* Cross Headers::       Finding and installing header files
+                          for a cross-compiler.
+* Build Cross::         Actually compiling the cross-compiler.
+@end menu
+@end ifnothtml
+
+@ifnothtml
+@node Steps of Cross, Configure Cross, , Cross-Compiler
+@subsection Steps of Cross-Compilation
+@end ifnothtml
+@html
+<h2>Steps of Cross-Compilation</h2>
+@end html
+
+To compile and run a program using a cross-compiler involves several
+steps:
+
+@itemize @bullet
+@item
+Run the cross-compiler on the host machine to produce assembler files
+for the target machine.  This requires header files for the target
+machine.
+
+@item
+Assemble the files produced by the cross-compiler.  You can do this
+either with an assembler on the target machine, or with a
+cross-assembler on the host machine.
+
+@item
+Link those files to make an executable.  You can do this either with a
+linker on the target machine, or with a cross-linker on the host
+machine.  Whichever machine you use, you need libraries and certain
+startup files (typically @file{crt@dots{}.o}) for the target machine.
+@end itemize
+
+It is most convenient to do all of these steps on the same host machine,
+since then you can do it all with a single invocation of GNU CC@.  This
+requires a suitable cross-assembler and cross-linker.  For some targets,
+the GNU assembler and linker are available.
+
+@ifnothtml
+@node Configure Cross, Tools and Libraries, Steps of Cross, Cross-Compiler
+@subsection Configuring a Cross-Compiler
+@end ifnothtml
+@html
+<h2>Configuring a Cross-Compiler</h2>
+@end html
+
+To build GNU CC as a cross-compiler, you start out by running
+@file{configure}.  Use the @option{--target=@var{target}} to specify the
+target type.  If @file{configure} was unable to correctly identify the
+system you are running on, also specify the @option{--build=@var{build}}
+option.  For example, here is how to configure for a cross-compiler that
+produces code for an HP 68030 system running BSD on a system that
+@file{configure} can correctly identify:
+
+@smallexample
+./configure --target=m68k-hp-bsd4.3
+@end smallexample
+
+@ifnothtml
+@node Tools and Libraries, Cross Headers, Configure Cross, Cross-Compiler
+@subsection Tools and Libraries for a Cross-Compiler
+@end ifnothtml
+@html
+<h2>Tools and Libraries for a Cross-Compiler</h2>
+@end html
+
+If you have a cross-assembler and cross-linker available, you should
+install them now.  Put them in the directory
+@file{/usr/local/@var{target}/bin}.  Here is a table of the tools
+you should put in this directory:
+
+@table @file
+@item as
+This should be the cross-assembler.
+
+@item ld
+This should be the cross-linker.
+
+@item ar
+This should be the cross-archiver: a program which can manipulate
+archive files (linker libraries) in the target machine's format.
+
+@item ranlib
+This should be a program to construct a symbol table in an archive file.
+@end table
+
+The installation of GNU CC will find these programs in that directory,
+and copy or link them to the proper place to for the cross-compiler to
+find them when run later.
+
+The easiest way to provide these files is to build the Binutils package
+and GAS@.  Configure them with the same @option{--host} and @option{--target}
+options that you use for configuring GNU CC, then build and install
+them.  They install their executables automatically into the proper
+directory.  Alas, they do not support all the targets that GNU CC
+supports.
+
+If you want to install libraries to use with the cross-compiler, such as
+a standard C library, put them in the directory
+@file{/usr/local/@var{target}/lib}; installation of GNU CC copies
+all the files in that subdirectory into the proper place for GNU CC to
+find them and link with them.  Here's an example of copying some
+libraries from a target machine:
+
+@example
+ftp @var{target-machine}
+lcd /usr/local/@var{target}/lib
+cd /lib
+get libc.a
+cd /usr/lib
+get libg.a
+get libm.a
+quit
+@end example
+
+@noindent
+The precise set of libraries you'll need, and their locations on
+the target machine, vary depending on its operating system.
+
+@cindex start files
+Many targets require ``start files'' such as @file{crt0.o} and
+@file{crtn.o} which are linked into each executable; these too should be
+placed in @file{/usr/local/@var{target}/lib}.  There may be several
+alternatives for @file{crt0.o}, for use with profiling or other
+compilation options.  Check your target's definition of
+@code{STARTFILE_SPEC} to find out what start files it uses.
+Here's an example of copying these files from a target machine:
+
+@example
+ftp @var{target-machine}
+lcd /usr/local/@var{target}/lib
+prompt
+cd /lib
+mget *crt*.o
+cd /usr/lib
+mget *crt*.o
+quit
+@end example
+
+@ifnothtml
+@node Cross Headers, Build Cross, Tools and Libraries, Cross-Compiler
+@subsection Cross-Compilers and Header Files
+@end ifnothtml
+@html
+<h2>Cross-Compilers and Header Files</h2>
+@end html
+
+If you are cross-compiling a standalone program or a program for an
+embedded system, then you may not need any header files except the few
+that are part of GNU CC (and those of your program).  However, if you
+intend to link your program with a standard C library such as
+@file{libc.a}, then you probably need to compile with the header files
+that go with the library you use.
+
+The GNU C compiler does not come with these files, because (1) they are
+system-specific, and (2) they belong in a C library, not in a compiler.
+
+If the GNU C library supports your target machine, then you can get the
+header files from there (assuming you actually use the GNU library when
+you link your program).
+
+If your target machine comes with a C compiler, it probably comes with
+suitable header files also.  If you make these files accessible from the host
+machine, the cross-compiler can use them also.
+
+Otherwise, you're on your own in finding header files to use when
+cross-compiling.
+
+When you have found suitable header files, you should put them in the
+directory @file{/usr/local/@var{target}/include}, before building the
+cross compiler.  Then installation will run fixincludes properly and
+install the corrected versions of the header files where the compiler
+will use them.
+
+Provide the header files before you build the cross-compiler, because
+the build stage actually runs the cross-compiler to produce parts of
+@file{libgcc.a}.  (These are the parts that @emph{can} be compiled with
+GNU CC@.)  Some of them need suitable header files.
+
+Here's an example showing how to copy the header files from a target
+machine.  On the target machine, do this:
+
+@example
+(cd /usr/include; tar cf - .) > tarfile
+@end example
+
+Then, on the host machine, do this:
+
+@example
+ftp @var{target-machine}
+lcd /usr/local/@var{target}/include
+get tarfile
+quit
+tar xf tarfile
+@end example
+
+@ifnothtml
+@node Build Cross, , Cross Headers, Cross-Compiler
+@subsection Actually Building the Cross-Compiler
+@end ifnothtml
+@html
+<h2>Actually Building the Cross-Compiler</h2>
+@end html
+
+Now you can proceed just as for compiling a single-machine compiler
+through the step of building stage 1.
+
+If your target is exotic, you may need to provide the header file
+@file{float.h}.One way to do this is to compile @file{enquire} and run
+it on your target machine.  The job of @file{enquire} is to run on the
+target machine and figure out by experiment the nature of its floating
+point representation.  @file{enquire} records its findings in the header
+file @file{float.h}.  If you can't produce this file by running
+@file{enquire} on the target machine, then you will need to come up with
+a suitable @file{float.h} in some other way (or else, avoid using it in
+your programs).
+
+Do not try to build stage 2 for a cross-compiler.  It doesn't work to
+rebuild GNU CC as a cross-compiler using the cross-compiler, because
+that would produce a program that runs on the target machine, not on the
+host.  For example, if you compile a 386-to-68030 cross-compiler with
+itself, the result will not be right either for the 386 (because it was
+compiled into 68030 code) or for the 68030 (because it was configured
+for a 386 as the host).  If you want to compile GNU CC into 68030 code,
+whether you compile it on a 68030 or with a cross-compiler on a 386, you
+must specify a 68030 as the host when you configure it.
+
+To install the cross-compiler, use @samp{make install}, as usual.
+
+@ifnothtml
+@node VMS Install, , Cross-Compiler, Old
+@section Installing GNU CC on VMS
+@end ifnothtml
+@html
+<h2>@anchor{VMS Install}Installing GNU CC on VMS</h2>
+@end html
+@cindex VMS installation
+@cindex installing GNU CC on VMS
+
+The VMS version of GNU CC is distributed in a backup saveset containing
+both source code and precompiled binaries.
+
+To install the @file{gcc} command so you can use the compiler easily, in
+the same manner as you use the VMS C compiler, you must install the VMS CLD
+file for GNU CC as follows:
+
+@enumerate
+@item
+Define the VMS logical names @samp{GNU_CC} and @samp{GNU_CC_INCLUDE}
+to point to the directories where the GNU CC executables
+(@file{gcc-cpp.exe}, @file{gcc-cc1.exe}, etc.) and the C include files are
+kept respectively.  This should be done with the commands:
+
+@smallexample
+$ assign /system /translation=concealed -
+  disk:[gcc.] gnu_cc
+$ assign /system /translation=concealed -
+  disk:[gcc.include.] gnu_cc_include
+@end smallexample
+
+@noindent
+with the appropriate disk and directory names.  These commands can be
+placed in your system startup file so they will be executed whenever
+the machine is rebooted.  You may, if you choose, do this via the
+@file{GCC_INSTALL.COM} script in the @file{[GCC]} directory.
+
+@item
+Install the @file{GCC} command with the command line:
+
+@smallexample
+$ set command /table=sys$common:[syslib]dcltables -
+  /output=sys$common:[syslib]dcltables gnu_cc:[000000]gcc
+$ install replace sys$common:[syslib]dcltables
+@end smallexample
+
+@item
+To install the help file, do the following:
+
+@smallexample
+$ library/help sys$library:helplib.hlb gcc.hlp
+@end smallexample
+
+@noindent
+Now you can invoke the compiler with a command like @samp{gcc /verbose
+file.c}, which is equivalent to the command @samp{gcc -v -c file.c} in
+Unix.
+@end enumerate
+
+If you wish to use GNU C++ you must first install GNU CC, and then
+perform the following steps:
+
+@enumerate
+@item
+Define the VMS logical name @samp{GNU_GXX_INCLUDE} to point to the
+directory where the preprocessor will search for the C++ header files.
+This can be done with the command:
+
+@smallexample
+$ assign /system /translation=concealed -
+  disk:[gcc.gxx_include.] gnu_gxx_include
+@end smallexample
+
+@noindent
+with the appropriate disk and directory name.  If you are going to be
+using a C++ runtime library, this is where its install procedure will install
+its header files.
+
+@item
+Obtain the file @file{gcc-cc1plus.exe}, and place this in the same
+directory that @file{gcc-cc1.exe} is kept.
+
+The GNU C++ compiler can be invoked with a command like @samp{gcc /plus
+/verbose file.cc}, which is equivalent to the command @samp{g++ -v -c
+file.cc} in Unix.
+@end enumerate
+
+We try to put corresponding binaries and sources on the VMS distribution
+tape.  But sometimes the binaries will be from an older version than the
+sources, because we don't always have time to update them.  (Use the
+@samp{/version} option to determine the version number of the binaries and
+compare it with the source file @file{version.c} to tell whether this is
+so.)  In this case, you should use the binaries you get to recompile the
+sources.  If you must recompile, here is how:
+
+@enumerate
+@item
+Execute the command procedure @file{vmsconfig.com} to set up the files
+@file{tm.h}, @file{config.h}, @file{aux-output.c}, and @file{md.}, and
+to create files @file{tconfig.h} and @file{hconfig.h}.  This procedure
+also creates several linker option files used by @file{make-cc1.com} and
+a data file used by @file{make-l2.com}.
+
+@smallexample
+$ @@vmsconfig.com
+@end smallexample
+
+@item
+Setup the logical names and command tables as defined above.  In
+addition, define the VMS logical name @samp{GNU_BISON} to point at the
+to the directories where the Bison executable is kept.  This should be
+done with the command:
+
+@smallexample
+$ assign /system /translation=concealed -
+  disk:[bison.] gnu_bison
+@end smallexample
+
+You may, if you choose, use the @file{INSTALL_BISON.COM} script in the
+@file{[BISON]} directory.
+
+@item
+Install the @samp{BISON} command with the command line:
+
+@smallexample
+$ set command /table=sys$common:[syslib]dcltables -
+  /output=sys$common:[syslib]dcltables -
+  gnu_bison:[000000]bison
+$ install replace sys$common:[syslib]dcltables
+@end smallexample
+
+@item
+Type @samp{@@make-gcc} to recompile everything, or submit the file
+@file{make-gcc.com} to a batch queue.  If you wish to build the GNU C++
+compiler as well as the GNU CC compiler, you must first edit
+@file{make-gcc.com} and follow the instructions that appear in the
+comments.
+
+@item
+In order to use GCC, you need a library of functions which GCC compiled code
+will call to perform certain tasks, and these functions are defined in the
+file @file{libgcc2.c}.  To compile this you should use the command procedure
+@file{make-l2.com}, which will generate the library @file{libgcc2.olb}.
+@file{libgcc2.olb} should be built using the compiler built from
+the same distribution that @file{libgcc2.c} came from, and
+@file{make-gcc.com} will automatically do all of this for you.
+
+To install the library, use the following commands:
+
+@smallexample
+$ library gnu_cc:[000000]gcclib/delete=(new,eprintf)
+$ library gnu_cc:[000000]gcclib/delete=L_*
+$ library libgcc2/extract=*/output=libgcc2.obj
+$ library gnu_cc:[000000]gcclib libgcc2.obj
+@end smallexample
+
+The first command simply removes old modules that will be replaced with
+modules from @file{libgcc2} under different module names.  The modules
+@code{new} and @code{eprintf} may not actually be present in your
+@file{gcclib.olb}---if the VMS librarian complains about those modules
+not being present, simply ignore the message and continue on with the
+next command.  The second command removes the modules that came from the
+previous version of the library @file{libgcc2.c}.
+
+Whenever you update the compiler on your system, you should also update the
+library with the above procedure.
+
+@item
+You may wish to build GCC in such a way that no files are written to the
+directory where the source files reside.  An example would be the when
+the source files are on a read-only disk.  In these cases, execute the
+following DCL commands (substituting your actual path names):
+
+@smallexample
+$ assign dua0:[gcc.build_dir.]/translation=concealed, -
+         dua1:[gcc.source_dir.]/translation=concealed  gcc_build
+$ set default gcc_build:[000000]
+@end smallexample
+
+@noindent
+where the directory @file{dua1:[gcc.source_dir]} contains the source
+code, and the directory @file{dua0:[gcc.build_dir]} is meant to contain
+all of the generated object files and executables.  Once you have done
+this, you can proceed building GCC as described above.  (Keep in mind
+that @file{gcc_build} is a rooted logical name, and thus the device
+names in each element of the search list must be an actual physical
+device name rather than another rooted logical name).
+
+@item
+@strong{If you are building GNU CC with a previous version of GNU CC,
+you also should check to see that you have the newest version of the
+assembler}.  In particular, GNU CC version 2 treats global constant
+variables slightly differently from GNU CC version 1, and GAS version
+1.38.1 does not have the patches required to work with GCC version 2.
+If you use GAS 1.38.1, then @code{extern const} variables will not have
+the read-only bit set, and the linker will generate warning messages
+about mismatched psect attributes for these variables.  These warning
+messages are merely a nuisance, and can safely be ignored.
+
+@item
+If you want to build GNU CC with the VAX C compiler, you will need to
+make minor changes in @file{make-cccp.com} and @file{make-cc1.com}
+to choose alternate definitions of @code{CC}, @code{CFLAGS}, and
+@code{LIBS}.  See comments in those files.  However, you must
+also have a working version of the GNU assembler (GNU as, aka GAS) as
+it is used as the back end for GNU CC to produce binary object modules
+and is not included in the GNU CC sources.  GAS is also needed to
+compile @file{libgcc2} in order to build @file{gcclib} (see above);
+@file{make-l2.com} expects to be able to find it operational in
+@file{gnu_cc:[000000]gnu-as.exe}.
+
+To use GNU CC on VMS, you need the VMS driver programs
+@file{gcc.exe}, @file{gcc.com}, and @file{gcc.cld}.  They are
+distributed with the VMS binaries (@file{gcc-vms}) rather than the
+GNU CC sources.  GAS is also included in @file{gcc-vms}, as is Bison.
+
+Once you have successfully built GNU CC with VAX C, you should use the
+resulting compiler to rebuild itself.  Before doing this, be sure to
+restore the @code{CC}, @code{CFLAGS}, and @code{LIBS} definitions in
+@file{make-cccp.com} and @file{make-cc1.com}.  The second generation
+compiler will be able to take advantage of many optimizations that must
+be suppressed when building with other compilers.
+@end enumerate
+
+Under previous versions of GNU CC, the generated code would occasionally
+give strange results when linked with the sharable @file{VAXCRTL} library.
+Now this should work.
+
+Even with this version, however, GNU CC itself should not be linked with
+the sharable @file{VAXCRTL}.  The version of @code{qsort} in
+@file{VAXCRTL} has a bug (known to be present in VMS versions V4.6
+through V5.5) which causes the compiler to fail.
+
+The executables are generated by @file{make-cc1.com} and
+@file{make-cccp.com} use the object library version of @file{VAXCRTL} in
+order to make use of the @code{qsort} routine in @file{gcclib.olb}.  If
+you wish to link the compiler executables with the shareable image
+version of @file{VAXCRTL}, you should edit the file @file{tm.h} (created
+by @file{vmsconfig.com}) to define the macro @code{QSORT_WORKAROUND}.
+
+@code{QSORT_WORKAROUND} is always defined when GNU CC is compiled with
+VAX C, to avoid a problem in case @file{gcclib.olb} is not yet
+available.
diff --git a/contrib/gcc/doc/install.texi b/contrib/gcc/doc/install.texi
new file mode 100644
index 0000000..6913d03
--- /dev/null
+++ b/contrib/gcc/doc/install.texi
@@ -0,0 +1,3823 @@
+\input texinfo.tex    @c -*-texinfo-*-
+@c @ifnothtml
+@c %**start of header
+@setfilename install.info
+@settitle Installing GCC
+@setchapternewpage odd
+@c %**end of header
+@c @end ifnothtml
+
+@c Specify title for specific html page
+@ifset indexhtml
+@settitle Installing GCC
+@end ifset
+@ifset specifichtml
+@settitle Host/Target specific installation notes for GCC
+@end ifset
+@ifset downloadhtml
+@settitle Downloading GCC
+@end ifset
+@ifset configurehtml
+@settitle Installing GCC: Configuration
+@end ifset
+@ifset buildhtml
+@settitle Installing GCC: Building
+@end ifset
+@ifset testhtml
+@settitle Installing GCC: Testing
+@end ifset
+@ifset finalinstallhtml
+@settitle Installing GCC: Final installation
+@end ifset
+@ifset binarieshtml
+@settitle Installing GCC: Binaries
+@end ifset
+@ifset oldhtml
+@settitle Installing GCC: Old documentation
+@end ifset
+@ifset gfdlhtml
+@settitle Installing GCC: GNU Free Documentation License
+@end ifset
+
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+@c 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+@c *** Converted to texinfo by Dean Wakerley, dean@wakerley.com
+
+@c Include everything if we're not making html
+@ifnothtml
+@set indexhtml
+@set specifichtml
+@set downloadhtml
+@set configurehtml
+@set buildhtml
+@set testhtml
+@set finalinstallhtml
+@set binarieshtml
+@set oldhtml
+@set gfdlhtml
+@end ifnothtml
+
+@c Part 2 Summary Description and Copyright
+@macro copyrightnotice
+Copyright @copyright{} 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+@sp 1
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.1 or
+any later version published by the Free Software Foundation; with no
+Invariant Sections, the Front-Cover texts being (a) (see below), and
+with the Back-Cover Texts being (b) (see below).  A copy of the
+license is included in the section entitled ``@uref{./gfdl.html,,GNU
+Free Documentation License}''.
+
+(a) The FSF's Front-Cover Text is:
+
+     A GNU Manual
+
+(b) The FSF's Back-Cover Text is:
+
+     You have freedom to copy and modify this GNU Manual, like GNU
+     software.  Copies published by the Free Software Foundation raise
+     funds for GNU development.
+@end macro
+@ifinfo
+@copyrightnotice{}
+@end ifinfo
+
+@c Part 3 Titlepage and Copyright
+@titlepage
+@sp 10
+@comment The title is printed in a large font.
+@center @titlefont{Installing GCC}
+
+@c The following two commands start the copyright page.
+@page
+@vskip 0pt plus 1filll
+@copyrightnotice{}
+@end titlepage
+
+@c Part 4 Top node and Master Menu
+@ifinfo
+@node    Top, , , (dir)
+@comment node-name, next,          Previous, up
+
+@menu
+* Installing GCC::  This document describes the generic installation
+                    procedure for GCC as well as detailing some target
+                    specific installation instructions.
+
+* Specific::        Host/target specific installation notes for GCC.
+* Binaries::        Where to get pre-compiled binaries.
+
+* Old::             Old installation documentation.
+
+* GNU Free Documentation License:: How you can copy and share this manual.
+* Concept Index::   This index has two entries.
+@end menu
+@end ifinfo
+
+@c Part 5 The Body of the Document
+@c ***Installing GCC**********************************************************
+@ifnothtml
+@comment node-name,     next,          previous, up
+@node    Installing GCC, Binaries, , Top
+@end ifnothtml
+@ifset indexhtml
+@html
+<h1 align="center">Installing GCC</h1>
+@end html
+@ifnothtml
+@chapter Installing GCC
+@end ifnothtml
+
+The latest version of this document is always available at
+@uref{http://gcc.gnu.org/install/,,http://gcc.gnu.org/install/}.
+
+This document describes the generic installation procedure for GCC as well
+as detailing some target specific installation instructions.
+
+GCC includes several components that previously were separate distributions
+with their own installation instructions.  This document supersedes all
+package specific installation instructions.
+
+@emph{Before} starting the build/install procedure please check the
+@ifnothtml
+@ref{Specific, host/target specific installation notes}.
+@end ifnothtml
+@ifhtml
+@uref{specific.html,,host/target specific installation notes}.
+@end ifhtml
+We recommend you browse the entire generic installation instructions before
+you proceed.
+
+Lists of successful builds for released versions of GCC are
+available at our web pages for
+@uref{http://gcc.gnu.org/gcc-3.0/buildstat.html,,3.0}
+and
+@uref{http://gcc.gnu.org/gcc-2.95/buildstat.html,,2.95}.
+These lists are updated as new information becomes available.
+
+The installation procedure itself is broken into five steps.
+
+@ifinfo
+@menu
+* Downloading the source::
+* Configuration::
+* Building::
+* Testing:: (optional)
+* Final install::
+@end menu
+@end ifinfo
+@ifhtml
+@enumerate
+@item
+@uref{download.html,,Downloading the source}
+@item
+@uref{configure.html,,Configuration}
+@item
+@uref{build.html,,Building}
+@item
+@uref{test.html,,Testing} (optional)
+@item
+@uref{finalinstall.html,,Final install}
+@end enumerate
+@end ifhtml
+
+Please note that GCC does not support @samp{make uninstall} and probably
+won't do so in the near future as this would open a can of worms.  Instead,
+we suggest that you install GCC into a directory of its own and simply
+remove that directory when you do not need that specific version of GCC
+any longer, and, if shared libraries are installed there as well, no
+more binaries exist that use them.
+
+@ifhtml
+There are also some @uref{old.html,,old installation instructions},
+which are mostly obsolete but still contain some information which has
+not yet been merged into the main part of this manual.
+@end ifhtml
+
+@html
+<hr>
+<p>
+@end html
+@ifhtml
+@uref{./index.html,,Return to the GCC Installation page}
+
+@copyrightnotice{}
+@end ifhtml
+@end ifset
+
+@c ***Downloading the source**************************************************
+@ifnothtml
+@comment node-name,     next,          previous, up
+@node    Downloading the source, Configuration, , Installing GCC
+@end ifnothtml
+@ifset downloadhtml
+@html
+<h1 align="center">Downloading GCC</h1>
+@end html
+@ifnothtml
+@chapter Downloading GCC
+@end ifnothtml
+@cindex Downloading GCC
+@cindex Downloading the Source
+
+GCC is distributed via @uref{http://gcc.gnu.org/cvs.html,,CVS} and FTP
+tarballs compressed with @command{gzip} or
+@command{bzip2}.  It is possible to download a full distribution or specific
+components.
+
+Please refer to our @uref{http://gcc.gnu.org/releases.html,,releases web page}
+for information on how to obtain GCC@.
+
+The full distribution includes the C, C++, Objective-C, Fortran, Java,
+and CHILL compilers.  The full distribution also includes runtime libraries
+for C++, Objective-C, Fortran, Java and CHILL.  (GCC 3.0 does not
+include CHILL.)  In GCC 3.0 and later versions, GNU compiler testsuites
+are also included in the full distribution.
+
+If you choose to download specific components, you must download the core
+GCC distribution plus any language specific distributions you wish to
+use.  The core distribution includes the C language front end as well as the
+shared components.  Each language has a tarball which includes the language
+front end as well as the language runtime (when appropriate).
+
+Unpack the core distribution as well as any language specific
+distributions in the same directory.
+
+If you also intend to build binutils (either to upgrade an existing
+installation or for use in place of the corresponding tools of your
+OS), unpack the binutils distribution either in the same directory or
+a separate one.  In the latter case, add symbolic links to any
+components of the binutils you intend to build alongside the compiler
+(@file{bfd}, @file{binutils}, @file{gas}, @file{gprof}, @file{ld},
+@file{opcodes}, @dots{}) to the directory containing the GCC sources.
+
+@html
+<hr>
+<p>
+@end html
+@ifhtml
+@uref{./index.html,,Return to the GCC Installation page}
+@end ifhtml
+@end ifset
+
+@c ***Configuration***********************************************************
+@ifnothtml
+@comment node-name,     next,          previous, up
+@node    Configuration, Building, Downloading the source, Installing GCC
+@end ifnothtml
+@ifset configurehtml
+@html
+<h1 align="center">Installing GCC: Configuration</h1>
+@end html
+@ifnothtml
+@chapter Installing GCC: Configuration
+@end ifnothtml
+@cindex Configuration
+@cindex Installing GCC: Configuration
+
+Like most GNU software, GCC must be configured before it can be built.
+This document describes the recommended configuration procedure
+for both native and cross targets.
+
+We use @var{srcdir} to refer to the toplevel source directory for
+GCC; we use @var{objdir} to refer to the toplevel build/object directory.
+
+If you obtained the sources via CVS, @var{srcdir} must refer to the top
+@file{gcc} directory, the one where the @file{MAINTAINERS} can be found,
+and not its @file{gcc} subdirectory, otherwise the build will fail.
+
+First, we @strong{highly} recommend that GCC be built into a
+separate directory than the sources which does @strong{not} reside
+within the source tree.  This is how we generally build GCC; building
+where @var{srcdir} == @var{objdir} should still work, but doesn't
+get extensive testing; building where @var{objdir} is a subdirectory
+of @var{srcdir} is unsupported.
+
+If you have previously built GCC in the same directory for a
+different target machine, do @samp{make distclean} to delete all files
+that might be invalid.  One of the files this deletes is
+@file{Makefile}; if @samp{make distclean} complains that @file{Makefile}
+does not exist, it probably means that the directory is already suitably
+clean.  However, with the recommended method of building in a separate
+@var{objdir}, you should simply use a different @var{objdir} for each
+target.
+
+Second, when configuring a native system, either @command{cc} or
+@command{gcc} must be in your path or you must set @env{CC} in
+your environment before running configure.  Otherwise the configuration
+scripts may fail.
+
+Note that the bootstrap compiler and the resulting GCC must be link
+compatible, else the bootstrap will fail with linker errors about
+incompatible object file formats.  Several multilibed targets are
+affected by this requirement, see
+@ifnothtml
+@ref{Specific, host/target specific installation notes}.
+@end ifnothtml
+@ifhtml
+@uref{specific.html,,host/target specific installation notes}.
+@end ifhtml
+
+To configure GCC:
+
+@example
+   % mkdir @var{objdir}
+   % cd @var{objdir}
+   % @var{srcdir}/configure [@var{options}] [@var{target}]
+@end example
+
+
+@heading Target specification
+@itemize @bullet
+@item
+GCC has code to correctly determine the correct value for @var{target}
+for nearly all native systems.  Therefore, we highly recommend you not
+provide a configure target when configuring a native compiler.
+
+@item
+@var{target} must be specified as @option{--target=@var{target}}
+when configuring a cross compiler; examples of valid targets would be
+i960-rtems, m68k-coff, sh-elf, etc.
+
+@item
+Specifying just @var{target} instead of @option{--target=@var{target}}
+implies that the host defaults to @var{target}.
+@end itemize
+
+
+@heading Options specification
+
+Use @var{options} to override several configure time options for
+GCC@.  A list of supported @var{options} follows; @command{configure
+--help} may list other options, but those not listed below may not
+work and should not normally be used.
+
+@table @code
+@item --prefix=@var{dirname}
+Specify the toplevel installation
+directory.  This is the recommended way to install the tools into a directory
+other than the default.  The toplevel installation directory defaults to
+@file{/usr/local}.
+
+We @strong{highly} recommend against @var{dirname} being the same or a
+subdirectory of @var{objdir} or vice versa.
+
+These additional options control where certain parts of the distribution
+are installed.  Normally you should not need to use these options.
+@table @code
+
+@item --exec-prefix=@var{dirname}
+Specify the toplevel installation directory for architecture-dependent
+files.  The default is @file{@var{prefix}}.
+
+@item --bindir=@var{dirname}
+Specify the installation directory for the executables called by users
+(such as @command{gcc} and @command{g++}).  The default is
+@file{@var{exec-prefix}/bin}.
+
+@item --libdir=@var{dirname}
+Specify the installation directory for object code libraries and
+internal parts of GCC@.  The default is @file{@var{exec-prefix}/lib}.
+
+@item --with-slibdir=@var{dirname}
+Specify the installation directory for the shared libgcc library.  The
+default is @file{@var{libdir}}.
+
+@item --infodir=@var{dirname}
+Specify the installation directory for documentation in info format.
+The default is @file{@var{prefix}/info}.
+
+@item --mandir=@var{dirname}
+Specify the installation directory for manual pages.  The default is
+@file{@var{prefix}/man}.  (Note that the manual pages are only extracts from
+the full GCC manuals, which are provided in Texinfo format.  The
+@command{g77} manpage is unmaintained and may be out of date; the others
+are derived by an automatic conversion process from parts of the full
+manual.)
+
+@item --with-gxx-include-dir=@var{dirname}
+Specify
+the installation directory for G++ header files.  The default is
+@file{@var{prefix}/include/g++-v3}.
+
+@end table
+
+@item --program-prefix=@var{prefix}
+GCC supports some transformations of the names of its programs when
+installing them. This option prepends @var{prefix} to the names of
+programs to install in @var{bindir} (see above). For example, specifying
+@option{--program-prefix=foo-} would result in @samp{gcc}
+being installed as @file{/usr/local/bin/foo-gcc}.
+
+@item --program-suffix=@var{suffix}
+Appends @var{suffix} to the names of programs to install in @var{bindir}
+(see above). For example, specifying @option{--program-suffix=-3.1}
+would result in @samp{gcc} being installed as
+@file{/usr/local/bin/gcc-3.1}.
+
+@item --program-transform-name=@var{pattern}
+Applies the @samp{sed} script @var{pattern} to be applied to the names
+of programs to install in @var{bindir} (see above). @var{pattern} has to
+consist of one or more basic @samp{sed} editing commands, separated by
+semicolons. For example, if you want the @samp{gcc} program name to be
+transformed to the installed program @file{/usr/local/bin/myowngcc} and
+the @samp{g++} program name to be transformed to
+@file{/usr/local/bin/gspecial++} without changing other program names,
+you could use the pattern
+@option{--program-transform-name='s/^gcc$/myowngcc/; s/^g++$/gspecial++/'}
+to achieve this effect.
+
+All three options can be combined and used together, resulting in more
+complex conversion patterns. As a basic rule, @var{prefix} (and
+@var{suffix}) are prepended (appended) before further transformations
+can happen with a special transformation script @var{pattern}.
+
+As currently implemented, this options only take effect for native
+builds; cross compiler binaries' names are not transformed even when a
+transformation is explicitly asked for by one of this options.
+
+For native builds, some of the installed programs are also installed
+with the target alias in front of their name, as in
+@samp{i686-pc-linux-gnu-gcc}. All of the above transformations happen
+before the target alias is prepended to the name - so, specifying
+@option{--program-prefix=foo-} and @option{program-suffix=-3.1}, the
+resulting binary would be installed as
+@file{/usr/local/bin/i686-pc-linux-gnu-foo-gcc-3.1}.
+
+As a last shortcoming, none of the installed CHILL and Ada programs are
+transformed yet, which will be fixed in some time.
+
+@item --with-local-prefix=@var{dirname}
+Specify the
+installation directory for local include files.  The default is
+@file{/usr/local}.  Specify this option if you want the compiler to
+search directory @file{@var{dirname}/include} for locally installed
+header files @emph{instead} of @file{/usr/local/include}.
+
+You should specify @option{--with-local-prefix} @strong{only} if your
+site has a different convention (not @file{/usr/local}) for where to put
+site-specific files.
+
+The default value for @option{--with-local-prefix} is @file{/usr/local}
+regardless of the value of @option{--prefix}.  Specifying
+@option{--prefix} has no effect on which directory GCC searches for
+local header files.  This may seem counterintuitive, but actually it is
+logical.
+
+The purpose of @option{--prefix} is to specify where to @emph{install
+GCC}.  The local header files in @file{/usr/local/include}---if you put
+any in that directory---are not part of GCC@.  They are part of other
+programs---perhaps many others.  (GCC installs its own header files in
+another directory which is based on the @option{--prefix} value.)
+
+@strong{Do not} specify @file{/usr} as the @option{--with-local-prefix}!
+The directory you use for @option{--with-local-prefix} @strong{must not}
+contain any of the system's standard header files.  If it did contain
+them, certain programs would be miscompiled (including GNU Emacs, on
+certain targets), because this would override and nullify the header
+file corrections made by the @code{fixincludes} script.
+
+Indications are that people who use this option use it based on mistaken
+ideas of what it is for.  People use it as if it specified where to
+install part of GCC@.  Perhaps they make this assumption because
+installing GCC creates the directory.
+
+@item --enable-shared[=@var{package}[,@dots{}]]
+Build shared versions of libraries, if shared libraries are supported on
+the target platform.  Unlike GCC 2.95.x and earlier, shared libraries
+are enabled by default on all platforms that support shared libraries,
+except for @samp{libobjc} which is built as a static library only by
+default.
+
+If a list of packages is given as an argument, build shared libraries
+only for the listed packages.  For other packages, only static libraries
+will be built.  Package names currently recognized in the GCC tree are
+@samp{libgcc} (also known as @samp{gcc}), @samp{libstdc++} (not
+@samp{libstdc++-v3}), @samp{libffi}, @samp{zlib}, @samp{boehm-gc} and
+@samp{libjava}.  Note that @samp{libobjc} does not recognize itself by
+any name, so, if you list package names in @option{--enable-shared},
+you will only get static Objective-C libraries.  @samp{libf2c} and
+@samp{libiberty} do not support shared libraries at all.
+
+Use @option{--disable-shared} to build only static libraries.  Note that
+@option{--disable-shared} does not accept a list of package names as
+argument, only @option{--enable-shared} does.
+
+@item @anchor{with-gnu-as}--with-gnu-as
+Specify that the compiler should assume that the
+assembler it finds is the GNU assembler.  However, this does not modify
+the rules to find an assembler and will result in confusion if found
+assembler is not actually the GNU assembler.  (Confusion will also
+result if the compiler finds the GNU assembler but has not been
+configured with @option{--with-gnu-as}.)  If you have more than one
+assembler installed on your system, you may want to use this option in
+connection with @option{--with-as=@var{pathname}}.
+
+The systems where it makes a difference whether you use the GNU assembler are
+@samp{hppa1.0-@var{any}-@var{any}}, @samp{hppa1.1-@var{any}-@var{any}},
+@samp{i386-@var{any}-sysv}, @samp{i386-@var{any}-isc},
+@samp{i860-@var{any}-bsd}, @samp{m68k-bull-sysv},
+@samp{m68k-hp-hpux}, @samp{m68k-sony-bsd},
+@samp{m68k-altos-sysv}, @samp{m68000-hp-hpux},
+@samp{m68000-att-sysv}, @samp{@var{any}-lynx-lynxos},
+and @samp{mips-@var{any}}.
+On any other system, @option{--with-gnu-as} has no effect.
+
+On the systems listed above (except for the HP-PA, for ISC on the
+386, and for @samp{mips-sgi-irix5.*}), if you use the GNU assembler,
+you should also use the GNU linker (and specify @option{--with-gnu-ld}).
+
+@item --with-as=@var{pathname}
+Specify that the
+compiler should use the assembler pointed to by @var{pathname}, rather
+than the one found by the standard rules to find an assembler, which
+are:
+@itemize @bullet
+@item
+Check the
+@file{@var{exec_prefix}/lib/gcc-lib/@var{target}/@var{version}}
+directory, where @var{exec_prefix} defaults to @var{prefix} which
+defaults to @file{/usr/local} unless overridden by the
+@option{--prefix=@var{pathname}} switch described above. @var{target} is the
+target system triple, such as @samp{sparc-sun-solaris2.7}, and
+@var{version} denotes the GCC version, such as 3.0.
+@item
+Check operating system specific directories (e.g.@: @file{/usr/ccs/bin} on
+Sun Solaris 2).
+@end itemize
+Note that these rules do not check for the value of @env{PATH}.  You may
+want to use @option{--with-as} if no assembler is installed in the
+directories listed above, or if you have multiple assemblers installed
+and want to choose one that is not found by the above rules.
+
+@item @anchor{with-gnu-ld}--with-gnu-ld
+Same as @uref{#with-gnu-as,,@option{--with-gnu-as}}
+but for linker.
+
+
+@item --with-ld=@var{pathname}
+Same as
+@option{--with-as}, but for the linker.
+
+@item --with-stabs
+Specify that stabs debugging
+information should be used instead of whatever format the host normally
+uses.  Normally GCC uses the same debug format as the host system.
+
+On MIPS based systems and on Alphas, you must specify whether you want
+GCC to create the normal ECOFF debugging format, or to use BSD-style
+stabs passed through the ECOFF symbol table.  The normal ECOFF debug
+format cannot fully handle languages other than C@.  BSD stabs format can
+handle other languages, but it only works with the GNU debugger GDB@.
+
+Normally, GCC uses the ECOFF debugging format by default; if you
+prefer BSD stabs, specify @option{--with-stabs} when you configure GCC@.
+
+No matter which default you choose when you configure GCC, the user
+can use the @option{-gcoff} and @option{-gstabs+} options to specify explicitly
+the debug format for a particular compilation.
+
+@option{--with-stabs} is meaningful on the ISC system on the 386, also, if
+@option{--with-gas} is used.  It selects use of stabs debugging
+information embedded in COFF output.  This kind of debugging information
+supports C++ well; ordinary COFF debugging information does not.
+
+@option{--with-stabs} is also meaningful on 386 systems running SVR4.  It
+selects use of stabs debugging information embedded in ELF output.  The
+C++ compiler currently (2.6.0) does not support the DWARF debugging
+information normally used on 386 SVR4 platforms; stabs provide a
+workable alternative.  This requires gas and gdb, as the normal SVR4
+tools can not generate or interpret stabs.
+
+@item --disable-multilib
+Specify that multiple target
+libraries to support different target variants, calling
+conventions, etc should not be built.  The default is to build a
+predefined set of them.
+
+Some targets provide finer-grained control over which multilibs are built
+(e.g., @option{--disable-softfloat}):
+@table @code
+
+@item arc-*-elf*
+biendian.
+
+@item arm-*-*
+fpu, 26bit, underscore, interwork, biendian, nofmult.
+
+@item m68*-*-*
+softfloat, m68881, m68000, m68020.
+
+@item mips*-*-*
+single-float, biendian, softfloat.
+
+@item powerpc*-*-*, rs6000*-*-*
+aix64, pthread, softfloat, powercpu, powerpccpu, powerpcos, biendian,
+sysv, aix. 
+
+@end table
+
+@item --enable-threads
+Specify that the target
+supports threads.  This affects the Objective-C compiler and runtime
+library, and exception handling for other languages like C++ and Java.
+On some systems, this is the default.
+
+In general, the best (and, in many cases, the only known) threading
+model available will be configured for use.  Beware that on some
+systems, gcc has not been taught what threading models are generally
+available for the system.  In this case, @option{--enable-threads} is an
+alias for @option{--enable-threads=single}.
+
+@item --disable-threads
+Specify that threading support should be disabled for the system.
+This is an alias for @option{--enable-threads=single}.
+
+@item --enable-threads=@var{lib}
+Specify that
+@var{lib} is the thread support library.  This affects the Objective-C
+compiler and runtime library, and exception handling for other languages
+like C++ and Java.  The possibilities for @var{lib} are:
+
+@table @code
+@item aix
+AIX thread support.
+@item dce
+DCE thread support.
+@item mach
+Generic MACH thread support, known to work on NeXTSTEP@.  (Please note
+that the file needed to support this configuration, @file{gthr-mach.h}, is
+missing and thus this setting will cause a known bootstrap failure.)
+@item no
+This is an alias for @samp{single}.
+@item posix
+Generic POSIX thread support.
+@item pthreads
+Same as @samp{posix} on arm*-*-linux*, *-*-chorusos* and *-*-freebsd*
+only.  A future release of gcc might remove this alias or extend it
+to all platforms.
+@item rtems
+RTEMS thread support.
+@item single
+Disable thread support, should work for all platforms.
+@item solaris
+Sun Solaris 2 thread support.
+@item vxworks
+VxWorks thread support.
+@item win32
+Microsoft Win32 API thread support.
+@end table
+
+@item --with-cpu=@var{cpu}
+Specify which cpu variant the
+compiler should generate code for by default.  This is currently
+only supported on the some ports, specifically arm, powerpc, and
+SPARC@.  If configure does not recognize the model name (e.g.@: arm700,
+603e, or ultrasparc) you provide, please check the configure script
+for a complete list of supported models.
+
+@item --enable-altivec
+Specify that the target supports AltiVec vector enhancements.  This
+option will adjust the ABI for AltiVec enhancements, as well as generate
+AltiVec code when appropriate.  This option is only available for
+PowerPC systems.
+
+@item --enable-target-optspace
+Specify that target
+libraries should be optimized for code space instead of code speed.
+This is the default for the m32r platform.
+
+@item --disable-cpp
+Specify that a user visible @command{cpp} program should not be installed.
+
+@item --with-cpp-install-dir=@var{dirname}
+Specify that the user visible @command{cpp} program should be installed
+in @file{@var{prefix}/@var{dirname}/cpp}, in addition to @var{bindir}.
+
+@item --enable-maintainer-mode
+The build rules that
+regenerate the GCC master message catalog @file{gcc.pot} are normally
+disabled.  This is because it can only be rebuilt if the complete source
+tree is present.  If you have changed the sources and want to rebuild the
+catalog, configuring with @option{--enable-maintainer-mode} will enable
+this.  Note that you need a recent version of the @code{gettext} tools
+to do so.
+
+@item --enable-version-specific-runtime-libs
+Specify
+that runtime libraries should be installed in the compiler specific
+subdirectory (@file{@var{libsubdir}}) rather than the usual places.  In
+addition, @samp{libstdc++}'s include files will be installed in
+@file{@var{libsubdir}/include/g++} unless you overruled it by using
+@option{--with-gxx-include-dir=@var{dirname}}.  Using this option is
+particularly useful if you intend to use several versions of GCC in
+parallel. This is currently supported by @samp{libf2c} and
+@samp{libstdc++}, and is the default for @samp{libobjc} which cannot be
+changed in this case.
+
+@item --enable-languages=@var{lang1},@var{lang2},@dots{}
+Specify that only a particular subset of compilers and
+their runtime libraries should be built.  For a list of valid values for
+@var{langN} you can issue the following command in the
+@file{gcc} directory of your GCC source tree:@*
+@example
+grep language= */config-lang.in
+@end example
+Currently, you can use any of the following:
+@code{ada}, @code{c}, @code{c++}, @code{f77}, @code{java}, @code{objc}.
+@code{CHILL} is not currently maintained, and will almost
+certainly fail to compile.  Building the Ada compiler has special
+requirements, see below.@*
+If you do not pass this flag, all languages available in the @file{gcc}
+sub-tree will be configured.  Re-defining @code{LANGUAGES} when calling
+@samp{make bootstrap} @strong{does not} work anymore, as those
+language sub-directories might not have been configured!
+
+@item --disable-libgcj
+Specify that the run-time libraries
+used by GCJ should not be built.  This is useful in case you intend
+to use GCJ with some other run-time, or you're going to install it
+separately, or it just happens not to build on your particular
+machine.  In general, if the Java front end is enabled, the GCJ
+libraries will be enabled too, unless they're known to not work on
+the target platform.  If GCJ is enabled but @samp{libgcj} isn't built, you
+may need to port it; in this case, before modifying the top-level
+@file{configure.in} so that @samp{libgcj} is enabled by default on this platform,
+you may use @option{--enable-libgcj} to override the default.
+
+@item --with-dwarf2
+Specify that the compiler should
+use DWARF 2 debugging information as the default.
+
+@item --enable-win32-registry
+@itemx --enable-win32-registry=@var{key}
+@itemx --disable-win32-registry
+The @option{--enable-win32-registry} option enables Windows-hosted GCC
+to look up installations paths in the registry using the following key:
+
+@smallexample
+@code{HKEY_LOCAL_MACHINE\SOFTWARE\Free Software Foundation\@var{key}}
+@end smallexample
+
+@var{key} defaults to GCC version number, and can be overridden by the
+@option{--enable-win32-registry=@var{key}} option. Vendors and distributors
+who use custom installers are encouraged to provide a different key,
+perhaps one comprised of vendor name and GCC version number, to
+avoid conflict with existing installations.  This feature is enabled
+by default, and can be disabled by @option{--disable-win32-registry}
+option.  This option has no effect on the other hosts.
+
+@item --nfp
+Specify that the machine does not have a floating point unit.  This
+option only applies to @samp{m68k-sun-sunos@var{n}} and
+@samp{m68k-isi-bsd}.  On any other system, @option{--nfp} has no effect.
+
+@item --enable-checking
+@itemx --enable-checking=@var{list}
+When you specify this option, the compiler is built to perform checking
+of tree node types when referencing fields of that node, and some other
+internal consistency checks.  This does not change the generated code,
+but adds error checking within the compiler.  This will slow down the
+compiler and may only work properly if you are building the compiler
+with GCC@.  This is on by default when building from CVS or snapshots,
+but off for releases.  More control over the checks may be had by
+specifying @var{list}; the categories of checks available are
+@samp{misc}, @samp{tree}, @samp{gc}, @samp{rtl} and @samp{gcac}.  The
+default when @var{list} is not specified is @samp{misc,tree,gc}; the
+checks @samp{rtl} and @samp{gcac} are very expensive.
+
+@item --enable-nls
+@itemx --disable-nls
+The @option{--enable-nls} option enables Native Language Support (NLS),
+which lets GCC output diagnostics in languages other than American
+English.  Native Language Support is enabled by default if not doing a
+canadian cross build.  The @option{--disable-nls} option disables NLS@.
+
+@item --with-included-gettext
+If NLS is enabled, the @option{--with-included-gettext} option causes the build
+procedure to prefer its copy of GNU @command{gettext}.
+
+@item --with-catgets
+If NLS is enabled, and if the host lacks @code{gettext} but has the
+inferior @code{catgets} interface, the GCC build procedure normally
+ignores @code{catgets} and instead uses GCC's copy of the GNU
+@code{gettext} library.  The @option{--with-catgets} option causes the
+build procedure to use the host's @code{catgets} in this situation.
+
+@item --with-system-zlib
+Use installed zlib rather than that included with GCC@.  This option
+only applies if the Java front end is being built.
+@end table
+
+Some options which only apply to building cross compilers:
+@table @code
+@item --with-headers=@var{dir}
+Specifies a directory
+which has target include files.
+@emph{This options is required} when building a cross
+compiler, if @file{@var{prefix}/@var{target}/sys-include} doesn't pre-exist.
+These include files will be copied into the @file{gcc} install directory.
+Fixincludes will be run on these files to make them compatible with
+GCC.
+@item --with-libs=``@var{dir1} @var{dir2} @dots{} @var{dirN}''
+Specifies a list of directories which contain the target runtime
+libraries.  These libraries will be copied into the @file{gcc} install
+directory.
+@item --with-newlib
+Specifies that @samp{newlib} is
+being used as the target C library.  This causes @code{__eprintf} to be
+omitted from @file{libgcc.a} on the assumption that it will be provided by
+@samp{newlib}.
+@end table
+
+Note that each @option{--enable} option has a corresponding
+@option{--disable} option and that each @option{--with} option has a
+corresponding @option{--without} option.
+
+@html
+<hr>
+<p>
+@end html
+@ifhtml
+@uref{./index.html,,Return to the GCC Installation page}
+@end ifhtml
+@end ifset
+
+@c ***Building****************************************************************
+@ifnothtml
+@comment node-name,     next,          previous, up
+@node    Building, Testing, Configuration, Installing GCC
+@end ifnothtml
+@ifset buildhtml
+@html
+<h1 align="center">Installing GCC: Building</h1>
+@end html
+@ifnothtml
+@chapter Building
+@end ifnothtml
+@cindex Installing GCC: Building
+
+Now that GCC is configured, you are ready to build the compiler and
+runtime libraries.
+
+We @strong{highly} recommend that GCC be built using GNU make;
+other versions may work, then again they might not.  
+GNU make is required for compiling GNAT, the Ada compiler.
+
+(For example, many broken versions of make will fail if you use the
+recommended setup where @var{objdir} is different from @var{srcdir}.
+Other broken versions may recompile parts of the compiler when
+installing the compiler.)
+
+Some commands executed when making the compiler may fail (return a
+nonzero status) and be ignored by @code{make}.  These failures, which
+are often due to files that were not found, are expected, and can safely
+be ignored.
+
+It is normal to have compiler warnings when compiling certain files.
+Unless you are a GCC developer, you can generally ignore these warnings
+unless they cause compilation to fail.
+
+On certain old systems, defining certain environment variables such as
+@env{CC} can interfere with the functioning of @command{make}.
+
+If you encounter seemingly strange errors when trying to build the
+compiler in a directory other than the source directory, it could be
+because you have previously configured the compiler in the source
+directory.  Make sure you have done all the necessary preparations.
+
+If you build GCC on a BSD system using a directory stored in an old System
+V file system, problems may occur in running @code{fixincludes} if the
+System V file system doesn't support symbolic links.  These problems
+result in a failure to fix the declaration of @code{size_t} in
+@file{sys/types.h}.  If you find that @code{size_t} is a signed type and
+that type mismatches occur, this could be the cause.
+
+The solution is not to use such a directory for building GCC@.
+
+When building from CVS or snapshots, or if you modify parser sources,
+you need the Bison parser generator installed.  Any version 1.25 or
+later should work; older versions may also work.  If you do not modify
+parser sources, releases contain the Bison-generated files and you do
+not need Bison installed to build them.
+
+When building from CVS or snapshots, or if you modify Texinfo
+documentation, you need version 4.0 or later of Texinfo installed if you
+want Info documentation to be regenerated.  Releases contain Info
+documentation pre-built for the unmodified documentation in the release.
+
+@section Building a native compiler
+
+For a native build issue the command @samp{make bootstrap}.  This
+will build the entire GCC system, which includes the following steps:
+
+@itemize @bullet
+@item
+Build host tools necessary to build the compiler such as texinfo, bison,
+gperf.
+
+@item
+Build target tools for use by the compiler such as binutils (bfd,
+binutils, gas, gprof, ld, and opcodes)
+if they have been individually linked 
+or moved into the top level GCC source tree before configuring.
+
+@item
+Perform a 3-stage bootstrap of the compiler.
+
+@item
+Perform a comparison test of the stage2 and stage3 compilers.
+
+@item
+Build runtime libraries using the stage3 compiler from the previous step.
+
+@end itemize
+
+If you are short on disk space you might consider @samp{make
+bootstrap-lean} instead.  This is identical to @samp{make
+bootstrap} except that object files from the stage1 and
+stage2 of the 3-stage bootstrap of the compiler are deleted as
+soon as they are no longer needed.
+
+
+If you want to save additional space during the bootstrap and in
+the final installation as well, you can build the compiler binaries
+without debugging information with @samp{make CFLAGS='-O' LIBCFLAGS='-g
+-O2' LIBCXXFLAGS='-g -O2 -fno-implicit-templates' bootstrap}.  This will save
+roughly 40% of disk space both for the bootstrap and the final installation.
+(Libraries will still contain debugging information.)
+
+If you wish to use non-default GCC flags when compiling the stage2 and
+stage3 compilers, set @code{BOOT_CFLAGS} on the command line when doing
+@samp{make bootstrap}.  Non-default optimization flags are less well
+tested here than the default of @samp{-g -O2}, but should still work.
+In a few cases, you may find that you need to specify special flags such
+as @option{-msoft-float} here to complete the bootstrap; or, if the
+native compiler miscompiles the stage1 compiler, you may need to work
+around this, by choosing @code{BOOT_CFLAGS} to avoid the parts of the
+stage1 compiler that were miscompiled, or by using @samp{make
+bootstrap4} to increase the number of stages of bootstrap.
+
+If you used the flag @option{--enable-languages=@dots{}} to restrict
+the compilers to be built, only those you've actually enabled will be
+built.  This will of course only build those runtime libraries, for
+which the particular compiler has been built.  Please note,
+that re-defining @env{LANGUAGES} when calling @samp{make bootstrap}
+@strong{does not} work anymore!
+
+If the comparison of stage2 and stage3 fails, this normally indicates
+that the stage2 compiler has compiled GCC incorrectly, and is therefore
+a potentially serious bug which you should investigate and report.  (On
+a few systems, meaningful comparison of object files is impossible; they
+always appear ``different''.  If you encounter this problem, you will
+need to disable comparison in the @file{Makefile}.)
+
+@section Building a cross compiler
+
+We recommend reading the
+@uref{http://www.objsw.com/CrossGCC/,,crossgcc FAQ}
+for information about building cross compilers.
+
+When building a cross compiler, it is not generally possible to do a
+3-stage bootstrap of the compiler.  This makes for an interesting problem
+as parts of GCC can only be built with GCC@.
+
+To build a cross compiler, we first recommend building and installing a
+native compiler.  You can then use the native GCC compiler to build the
+cross compiler.  The installed native compiler needs to be GCC version
+2.95 or later.
+
+Assuming you have already installed a native copy of GCC and configured
+your cross compiler, issue the command @command{make}, which performs the
+following steps:
+
+@itemize @bullet
+@item
+Build host tools necessary to build the compiler such as texinfo, bison,
+gperf.
+
+@item
+Build target tools for use by the compiler such as binutils (bfd,
+binutils, gas, gprof, ld, and opcodes)
+if they have been individually linked or moved into the top level GCC source
+tree before configuring.
+
+@item
+Build the compiler (single stage only).
+
+@item
+Build runtime libraries using the compiler from the previous step.
+@end itemize
+
+Note that if an error occurs in any step the make process will exit.
+
+@section Building in parallel
+
+If you have a multiprocessor system you can use @samp{make bootstrap
+MAKE="make -j 2" -j 2} or just @samp{make -j 2 bootstrap}
+for GNU Make 3.79 and above instead of just @samp{make bootstrap}
+when building GCC@.  You can use a bigger number instead of two if
+you like.  In most cases, it won't help to use a number bigger than
+the number of processors in your machine.
+
+@section Building the Ada compiler
+
+In order to build GNAT, the Ada compiler, you need a working GNAT
+compiler, since the Ada front end is written in Ada (with some
+GNAT-specific extensions), and GNU make.
+
+However, you do not need a full installation of GNAT, just the GNAT
+binary @file{gnat1}, a copy of @file{gnatbind}, and a compiler driver
+which can deal with Ada input (by invoking the @file{gnat1} binary).
+You can specify this compiler driver by setting the @env{ADAC}
+environment variable at the configure step.  @command{configure} can
+detect the driver automatically if it has got a common name such as
+@command{gcc} or @command{gnatgcc}.  Of course, you still need a working
+C compiler (the compiler driver can be different or not).
+
+Additional build tools (such as @command{gnatmake}) or a working GNAT
+run-time library installation are usually @emph{not} required.  However,
+if you want to boostrap the compiler using a minimal version of GNAT,
+you have to issue the following commands before invoking @samp{make
+boostrap} (this assumes that you start with an unmodified and consistent
+source distribution):
+
+@example
+    cd @var{srcdir}/gcc/ada
+    touch treeprs.ads [es]info.h nmake.ad[bs]
+@end example
+
+At the moment, the GNAT library and several tools for GNAT are not built
+by @samp{make bootstrap}.  You have to invoke 
+@samp{make gnatlib_and_tools} in the @file{@var{objdir}/gcc}
+subdirectory before proceeding with the next steps.
+
+For example, you can build a native Ada compiler by issuing the
+following commands (assuming @command{make} is GNU make):
+
+@example
+    cd @var{objdir}
+    @var{srcdir}/configure --enable-languages=c,ada 
+    cd @var{srcdir}/gcc/ada
+    touch treeprs.ads [es]info.h nmake.ad[bs]
+    cd @var{objdir}    
+    make bootstrap
+    cd gcc
+    make gnatlib_and_tools
+    cd ..
+@end example
+
+Currently, when compiling the Ada front end, you cannot use the parallel
+build feature described in the previous section.
+
+@html
+<hr>
+<p>
+@end html
+@ifhtml
+@uref{./index.html,,Return to the GCC Installation page}
+@end ifhtml
+@end ifset
+
+@c ***Testing*****************************************************************
+@ifnothtml
+@comment node-name,     next,          previous, up
+@node    Testing, Final install, Building, Installing GCC
+@end ifnothtml
+@ifset testhtml
+@html
+<h1 align="center">Installing GCC: Testing</h1>
+@end html
+@ifnothtml
+@chapter Installing GCC: Testing
+@end ifnothtml
+@cindex Testing
+@cindex Installing GCC: Testing
+@cindex Testsuite
+
+Before you install GCC, you might wish to run the testsuite.  This
+step is optional and may require you to download additional software.
+
+First, you must have @uref{download.html,,downloaded the testsuites}.
+The full distribution contains testsuites; only if you downloaded the
+``core'' compiler plus any front ends, you do not have the testsuites.
+
+Second, you must have a @uref{http://www.gnu.org/software/dejagnu/,,current version of DejaGnu} installed;
+dejagnu 1.3 is not sufficient.
+
+Now you may need specific preparations:
+
+@itemize @bullet
+
+@item
+The following environment variables may need to be set appropriately, as in
+the following example (which assumes that DejaGnu has been installed
+under @file{/usr/local}):
+
+@example
+     TCL_LIBRARY = /usr/local/share/tcl8.0
+     DEJAGNULIBS = /usr/local/share/dejagnu
+@end example
+
+On systems such as Cygwin, these paths are required to be actual
+paths, not mounts or links; presumably this is due to some lack of
+portability in the DejaGnu code.
+
+If the directories where @command{runtest} and @command{expect} were
+installed are in the @env{PATH}, it should not be necessary to set these
+environment variables.
+
+@end itemize
+
+Finally, you can run the testsuite (which may take a long time):
+@example
+     cd @var{objdir}; make -k check
+@end example
+
+The testing process will try to test as many components in the GCC
+distribution as possible, including the C, C++, Objective-C and Fortran
+compilers as well as the C++ and Java runtime libraries.
+
+@section How can I run the test suite on selected tests?
+
+As a first possibility to cut down the number of tests that are run it is
+possible to use @samp{make check-gcc} or @samp{make check-g++}
+in the @file{gcc} subdirectory of the object directory.  To further cut down the
+tests the following is possible:
+
+@example
+    make check-gcc RUNTESTFLAGS="execute.exp @var{other-options}"
+@end example
+
+This will run all @command{gcc} execute tests in the testsuite.
+
+@example
+    make check-g++ RUNTESTFLAGS="old-deja.exp=9805* @var{other-options}"
+@end example
+
+This will run the @command{g++} ``old-deja'' tests in the testsuite where the filename
+matches @samp{9805*}.
+
+The @file{*.exp} files are located in the testsuite directories of the GCC
+source, the most important ones being @file{compile.exp},
+@file{execute.exp}, @file{dg.exp} and @file{old-deja.exp}.
+To get a list of the possible @file{*.exp} files, pipe the
+output of @samp{make check} into a file and look at the
+@samp{Running @dots{}  .exp} lines.
+
+@section How to interpret test results
+
+After the testsuite has run you'll find various @file{*.sum} and @file{*.log}
+files in the testsuite subdirectories.  The @file{*.log} files contain a
+detailed log of the compiler invocations and the corresponding
+results, the @file{*.sum} files summarize the results.  These summaries list
+all the tests that have been run with a corresponding status code:
+
+@itemize @bullet
+@item
+PASS: the test passed as expected
+@item
+XPASS: the test unexpectedly passed
+@item
+FAIL: the test unexpectedly failed
+@item
+XFAIL: the test failed as expected
+@item
+UNSUPPORTED: the test is not supported on this platform
+@item
+ERROR: the testsuite detected an error
+@item
+WARNING: the testsuite detected a possible problem
+@end itemize
+
+It is normal for some tests to report unexpected failures.  At the
+current time our testing harness does not allow fine grained control
+over whether or not a test is expected to fail.  We expect to fix this
+problem in future releases.
+
+
+@section Submitting test results
+
+If you want to report the results to the GCC project, use the
+@file{contrib/test_summary} shell script.  Start it in the @var{objdir} with
+
+@example
+    @var{srcdir}/contrib/test_summary -p your_commentary.txt \
+        -m gcc-testresults@@gcc.gnu.org |sh
+@end example
+
+This script uses the @command{Mail} program to send the results, so
+make sure it is in your @env{PATH}.  The file @file{your_commentary.txt} is
+prepended to the testsuite summary and should contain any special
+remarks you have on your results or your build environment.  Please
+do not edit the testsuite result block or the subject line, as these
+messages are automatically parsed and presented at the
+@uref{http://gcc.gnu.org/testresults/,,GCC testresults} web
+page.  Here you can also gather information on how specific tests
+behave on different platforms and compare them with your results.  A
+few failing testcases are possible even on released versions and you
+should look here first if you think your results are unreasonable.
+
+@html
+<hr>
+<p>
+@end html
+@ifhtml
+@uref{./index.html,,Return to the GCC Installation page}
+@end ifhtml
+@end ifset
+
+@c ***Final install***********************************************************
+@ifnothtml
+@comment node-name,     next,          previous, up
+@node    Final install, , Testing, Installing GCC
+@end ifnothtml
+@ifset finalinstallhtml
+@html
+<h1 align="center">Installing GCC: Final installation</h1>
+@end html
+@ifnothtml
+@chapter Installing GCC: Final installation
+@end ifnothtml
+
+Now that GCC has been built (and optionally tested), you can install it with
+@example
+cd @var{objdir}; make install
+@end example
+
+That step completes the installation of GCC; user level binaries can
+be found in @file{@var{prefix}/bin} where @var{prefix} is the value you
+specified with the @option{--prefix} to configure (or @file{/usr/local}
+by default).  (If you specified @option{--bindir}, that directory will
+be used instead; otherwise, if you specified @option{--exec-prefix},
+@file{@var{exec-prefix}/bin} will be used.)  Headers for the C++ and
+Java libraries are installed in @file{@var{prefix}/include}; libraries
+in @file{@var{libdir}} (normally @file{@var{prefix}/lib}); internal
+parts of the compiler in @file{@var{libdir}/gcc-lib}; documentation in
+info format in @file{@var{infodir}} (normally @file{@var{prefix}/info}).
+
+If you built a released version of GCC then if you don't mind, please
+quickly review the build status page for
+@uref{http://gcc.gnu.org/gcc-3.0/buildstat.html,,3.0} or
+@uref{http://gcc.gnu.org/gcc-2.95/buildstat.html,,2.95}.
+If your system is not listed for the version of GCC that you built,
+send a note to
+@email{gcc@@gcc.gnu.org} indicating
+that you successfully built and installed GCC.
+Include the following information:
+
+@itemize @bullet
+@item
+Output from running @file{@var{srcdir}/config.guess}.  Do not send us
+that file itself, just the one-line output from running it.
+
+@item
+The output of @samp{gcc -v} for your newly installed gcc.
+This tells us which version of GCC you built and the options you passed to
+configure.
+
+@item
+If the build was for GNU/Linux, also include:
+@itemize @bullet
+@item
+The distribution name and version (e.g., Red Hat 7.1 or Debian 2.2.3);
+this information should be available from @file{/etc/issue}.
+
+@item
+The version of the Linux kernel, available from @samp{uname --version}
+or @samp{uname -a}.
+
+@item
+The version of glibc you used; for RPM-based systems like Red Hat,
+Mandrake, and SuSE type @samp{rpm -q glibc} to get the glibc version,
+and on systems like Debian and Progeny use @samp{dpkg -l libc6}.
+@end itemize
+For other systems, you can include similar information if you think it is
+relevant.
+
+@item
+Any other information that you think would be useful to people building
+GCC on the same configuration.  The new entry in the build status list
+will include a link to the archived copy of your message.
+@end itemize
+
+We'd also like to know if the
+@ifnothtml
+@ref{Specific, host/target specific installation notes}
+@end ifnothtml
+@ifhtml
+@uref{specific.html,,host/target specific installation notes}
+@end ifhtml
+didn't include your host/target information or if that information is
+incomplete or out of date.  Send a note to
+@email{gcc@@gcc.gnu.org} telling us how the information should be changed.
+
+If you find a bug, please report it following our
+@uref{../bugs.html,,bug reporting guidelines}.
+
+If you want to print the GCC manuals, do @samp{cd @var{objdir}; make
+dvi}.  You will need to have @command{texi2dvi} (version at least 4.0)
+and @TeX{} installed.  This creates a number of @file{.dvi} files in
+subdirectories of @file{@var{objdir}}; these may be converted for
+printing with programs such as @command{dvips}.  You can also
+@uref{http://www.gnu.org/order/order.html,,buy printed manuals from the
+Free Software Foundation}, though such manuals may not be for the most
+recent version of GCC@.
+
+@html
+<hr>
+<p>
+@end html
+@ifhtml
+@uref{./index.html,,Return to the GCC Installation page}
+@end ifhtml
+@end ifset
+
+@c ***Binaries****************************************************************
+@ifnothtml
+@comment node-name,     next,          previous, up
+@node    Binaries, Specific, Installing GCC, Top
+@end ifnothtml
+@ifset binarieshtml
+@html
+<h1 align="center">Installing GCC: Binaries</h1>
+@end html
+@ifnothtml
+@chapter Installing GCC: Binaries
+@end ifnothtml
+@cindex Binaries
+@cindex Installing GCC: Binaries
+
+We are often asked about pre-compiled versions of GCC@.  While we cannot
+provide these for all platforms, below you'll find links to binaries for
+various platforms where creating them by yourself is not easy due to various
+reasons.
+
+Please note that we did not create these binaries, nor do we
+support them.  If you have any problems installing them, please
+contact their makers.
+
+@itemize
+@item
+AIX:
+@itemize
+@item
+@uref{http://freeware.bull.net,,Bull's Freeware and Shareware Archive for AIX};
+
+@item
+@uref{http://aixpdslib.seas.ucla.edu,,UCLA Software Library for AIX};
+@end itemize
+
+@item
+DOS---@uref{http://www.delorie.com/djgpp/,,DJGPP};
+
+@item
+HP-UX:
+@itemize
+@item
+@uref{http://hpux.cae.wisc.edu/,,HP-UX Porting Center};
+
+@item
+@uref{ftp://sunsite.informatik.rwth-aachen.de/pub/packages/gcc_hpux/,,Binaries for HP-UX 11.00 at Aachen University of Technology}.
+@end itemize
+
+@item
+@uref{http://www.sco.com/skunkware/devtools/index.html#gcc,,SCO
+OpenServer/Unixware};
+
+@item
+Solaris 2 (SPARC, Intel)---@uref{http://www.sunfreeware.com/,,Sunfreeware};
+
+@item
+SGI---@uref{http://freeware.sgi.com/,,SGI Freeware};
+
+@item
+Windows 95, 98, and NT:
+@itemize
+@item
+The @uref{http://sources.redhat.com/cygwin/,,Cygwin} project;
+@item
+@uref{http://www.xraylith.wisc.edu/~khan/software/gnu-win32/,,GNU Win32}
+related projects by Mumit Khan.
+@end itemize
+
+@item
+@uref{ftp://ftp.thewrittenword.com/packages/free/by-name/,,The
+Written Word} offers binaries for Solaris 2.5.1, 2.6, 2.7/SPARC, 2.7/Intel,
+IRIX 6.2, 6.5, Digital UNIX 4.0D, HP-UX 10.20, and HP-UX 11.00.
+
+@item
+Hitachi H8/300[HS]---@uref{http://h8300-hms.sourceforge.net/,,GNU
+Development Tools for the Hitachi H8/300[HS] Series}
+
+@end itemize
+
+In addition to those specific offerings, you can get a binary
+distribution CD-ROM from the
+@uref{http://www.fsf.org/order/order.html,,Free Software Foundation}.
+It contains binaries for a number of platforms, and
+includes not only GCC, but other stuff as well.  The current CD does
+not contain the latest version of GCC, but it should allow
+bootstrapping the compiler.  An updated version of that disk is in the
+works.
+
+@html
+<hr>
+<p>
+@end html
+@ifhtml
+@uref{./index.html,,Return to the GCC Installation page}
+@end ifhtml
+@end ifset
+
+@c ***Specific****************************************************************
+@ifnothtml
+@comment node-name,     next,          previous, up
+@node    Specific, Old, Binaries, Top
+@end ifnothtml
+@ifset specifichtml
+@html
+<h1 align="center">Host/target specific installation notes for GCC</h1>
+@end html
+@ifnothtml
+@chapter Host/target specific installation notes for GCC
+@end ifnothtml
+@cindex Specific
+@cindex Specific installation notes
+@cindex Target specific installation
+@cindex Host specific installation
+@cindex Target specific installation notes
+
+Please read this document carefully @emph{before} installing the
+GNU Compiler Collection on your machine.
+
+Lists of successful builds for released versions of GCC are
+available at our web pages for
+@uref{http://gcc.gnu.org/gcc-3.0/buildstat.html,,3.0}
+and
+@uref{http://gcc.gnu.org/gcc-2.95/buildstat.html,,2.95}.
+These lists are updated as new information becomes available.
+
+@ifhtml
+@itemize
+@item
+@uref{#1750a-*-*,,1750a-*-*}
+@item
+@uref{#a29k,,a29k}
+@item
+@uref{#a29k-*-bsd,,a29k-*-bsd}
+@item
+@uref{#alpha*-*-*,,alpha*-*-*}
+@item
+@uref{#alpha*-dec-osf*,,alpha*-dec-osf*}
+@item
+@uref{#alphaev5-cray-unicosmk*,,alphaev5-cray-unicosmk*}
+@item
+@uref{#arc-*-elf,,arc-*-elf}
+@item
+@uref{#arm-*-aout,,arm-*-aout}
+@item
+@uref{#arm-*-elf,,arm-*-elf}
+@item
+@uref{#arm*-*-linux-gnu,,arm*-*-linux-gnu}
+@item
+@uref{#arm-*-riscix,,arm-*-riscix}
+@item
+@uref{#avr,,avr}
+@item
+@uref{#c4x,,c4x}
+@item
+@uref{#dos,,DOS}
+@item
+@uref{#dsp16xx,,dsp16xx}
+@item
+@uref{#elxsi-elxsi-bsd,,elxsi-elxsi-bsd}
+@item
+@uref{#*-*-freebsd*,,*-*-freebsd*}
+@item
+@uref{#h8300-hms,,h8300-hms}
+@item
+@uref{#hppa*-hp-hpux*,,hppa*-hp-hpux*}
+@item
+@uref{#hppa*-hp-hpux9,,hppa*-hp-hpux9}
+@item
+@uref{#hppa*-hp-hpux10,,hppa*-hp-hpux10}
+@item
+@uref{#hppa*-hp-hpux11,,hppa*-hp-hpux11}
+@item
+@uref{#i370-*-*,,i370-*-*}
+@item
+@uref{#*-*-linux-gnu,,*-*-linux-gnu}
+@item
+@uref{#ix86-*-linux*oldld,,i?86-*-linux*oldld}
+@item
+@uref{#ix86-*-linux*aout,,i?86-*-linux*aout}
+@item
+@uref{#ix86-*-linux*,,i?86-*-linux*}
+@item
+@uref{#ix86-*-sco,,i?86-*-sco}
+@item
+@uref{#ix86-*-sco3.2v4,,i?86-*-sco3.2v4}
+@item
+@uref{#ix86-*-sco3.2v5*,,i?86-*-sco3.2v5*}
+@item
+@uref{#ix86-*-udk,,i?86-*-udk}
+@item
+@uref{#ix86-*-isc,,i?86-*-isc}
+@item
+@uref{#ix86-*-esix,,i?86-*-esix}
+@item
+@uref{#ix86-ibm-aix,,i?86-ibm-aix}
+@item
+@uref{#ix86-sequent-bsd,,i?86-sequent-bsd}
+@item
+@uref{#ix86-sequent-ptx1*,,i?86-sequent-ptx1*, i?86-sequent-ptx2*}
+@item
+@uref{#ix86-*-sysv3*,,i?86-*-sysv3*}
+@item
+@uref{#i860-intel-osf*,,i860-intel-osf*}
+@item
+@uref{#ia64-*-linux,,ia64-*-linux}
+@item
+@uref{#*-lynx-lynxos,,*-lynx-lynxos}
+@item
+@uref{#*-ibm-aix*,,*-ibm-aix*}
+@item
+@uref{#m32r-*-elf,,m32r-*-elf}
+@item
+@uref{#m68000-hp-bsd,,m68000-hp-bsd}
+@item
+@uref{#m6811-elf,,m6811-elf}
+@item
+@uref{#m6812-elf,,m6812-elf}
+@item
+@uref{#m68k-altos,,m68k-altos}
+@item
+@uref{#m68k-apple-aux,,m68k-apple-aux}
+@item
+@uref{#m68k-att-sysv,,m68k-att-sysv}
+@item
+@uref{#m68k-bull-sysv,,m68k-bull-sysv}
+@item
+@uref{#m68k-crds-unox,,m68k-crds-unox}
+@item
+@uref{#m68k-hp-hpux,,m68k-hp-hpux}
+@item
+@uref{#m68k-*-nextstep*,,m68k-*-nextstep*}
+@item
+@uref{#m68k-ncr-*,,m68k-ncr-*}
+@item
+@uref{#m68k-sun,,m68k-sun}
+@item
+@uref{#m68k-sun-sunos4.1.1,,m68k-sun-sunos4.1.1}
+@item
+@uref{#m88k-*-svr3,,m88k-*-svr3}
+@item
+@uref{#m88k-*-dgux,,m88k-*-dgux}
+@item
+@uref{#m88k-tektronix-sysv3,,m88k-tektronix-sysv3}
+@item
+@uref{#mips-*-*,,mips-*-*}
+@item
+@uref{#mips-dec-*,,mips-dec-*}
+@item
+@uref{#mips-mips-bsd,,mips-mips-bsd}
+@item
+@uref{#mips-mips-riscos*,,mips-mips-riscos*}
+@item
+@uref{#mips-sgi-irix4,,mips-sgi-irix4}
+@item
+@uref{#mips-sgi-irix5,,mips-sgi-irix5}
+@item
+@uref{#mips-sgi-irix6,,mips-sgi-irix6}
+@item
+@uref{#mips-sony-sysv,,mips-sony-sysv}
+@item
+@uref{#ns32k-encore,,ns32k-encore}
+@item
+@uref{#ns32k-*-genix,,ns32k-*-genix}
+@item
+@uref{#ns32k-sequent,,ns32k-sequent}
+@item
+@uref{#ns32k-utek,,ns32k-utek}
+@item
+@uref{#powerpc*-*-*,,powerpc*-*-*, powerpc-*-sysv4}
+@item
+@uref{#powerpc-*-darwin*,,powerpc-*-darwin*}
+@item
+@uref{#powerpc-*-elf,,powerpc-*-elf, powerpc-*-sysv4}
+@item
+@uref{#powerpc-*-linux-gnu*,,powerpc-*-linux-gnu*}
+@item
+@uref{#powerpc-*-netbsd*,,powerpc-*-netbsd*}
+@item
+@uref{#powerpc-*-eabiaix,,powerpc-*-eabiaix}
+@item
+@uref{#powerpc-*-eabisim,,powerpc-*-eabisim}
+@item
+@uref{#powerpc-*-eabi,,powerpc-*-eabi}
+@item
+@uref{#powerpcle-*-elf,,powerpcle-*-elf, powerpcle-*-sysv4}
+@item
+@uref{#powerpcle-*-eabisim,,powerpcle-*-eabisim}
+@item
+@uref{#powerpcle-*-eabi,,powerpcle-*-eabi}
+@item
+@uref{#powerpcle-*-winnt,,powerpcle-*-winnt, powerpcle-*-pe}
+@item
+@uref{#romp-*-aos,,romp-*-aos, romp-*-mach}
+@item
+@uref{#s390-*-linux*}
+@item
+@uref{#s390x-*-linux*}
+@item
+@uref{#*-*-solaris2*,,*-*-solaris2*}
+@item
+@uref{#sparc-sun-solaris2*,,sparc-sun-solaris2*}
+@item
+@uref{#sparc-sun-solaris2.7,,sparc-sun-solaris2.7}
+@item
+@uref{#*-*-solaris2.8,,*-*-solaris2.8}
+@item
+@uref{#sparc-sun-sunos4*,,sparc-sun-sunos4*}
+@item
+@uref{#sparc-unknown-linux-gnulibc1,,sparc-unknown-linux-gnulibc1}
+@item
+@uref{#sparc-*-linux*,,sparc-*-linux*}
+@item
+@uref{#sparc64-*-*,,sparc64-*-*}
+@item
+@uref{#sparcv9-*-solaris2*,,sparcv9-*-solaris2*}
+@item
+@uref{#*-*-sysv*,,*-*-sysv*}
+@item
+@uref{#vax-dec-ultrix,,vax-dec-ultrix}
+@item
+@uref{#we32k-*-*,,we32k-*-*}
+@item
+@uref{#xtensa-*-elf,,xtensa-*-elf}
+@item
+@uref{#xtensa-*-linux*,,xtensa-*-linux*}
+@item
+@uref{#windows,,Microsoft Windows}
+@item
+@uref{#os2,,OS/2}
+@item
+@uref{#older,,Older systems}
+@end itemize
+
+@itemize
+@item
+@uref{#elf_targets,,all ELF targets} (SVR4, Solaris 2, etc.)
+@end itemize
+@end ifhtml
+
+
+@html
+<!-- -------- host/target specific issues start here ---------------- -->
+<hr>
+@end html
+@heading @anchor{1750a-*-*}1750a-*-*
+MIL-STD-1750A processors.
+
+The MIL-STD-1750A cross configuration produces output for
+@code{as1750}, an assembler/linker available under the GNU General Public
+License for the 1750A@.  @code{as1750} can be obtained at
+@uref{ftp://ftp.fta-berlin.de/pub/crossgcc/1750gals/}.
+A similarly licensed simulator for
+the 1750A is available from same address.
+
+You should ignore a fatal error during the building of @samp{libgcc}
+(@samp{libgcc} is not yet implemented for the 1750A@.)
+
+The @code{as1750} assembler requires the file @file{ms1750.inc}, which is
+found in the directory @file{gcc/config/1750a}.
+
+GCC produced the same sections as the Fairchild F9450 C Compiler,
+namely:
+
+@table @code
+@item Normal
+The program code section.
+
+@item Static
+The read/write (RAM) data section.
+
+@item Konst
+The read-only (ROM) constants section.
+
+@item Init
+Initialization section (code to copy KREL to SREL)@.
+@end table
+
+The smallest addressable unit is 16 bits (@code{BITS_PER_UNIT} is 16).  This
+means that type @code{char} is represented with a 16-bit word per character.
+The 1750A's ``Load/Store Upper/Lower Byte'' instructions are not used by
+GCC@.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{a29k}a29k
+AMD Am29k-family processors.  These are normally used in embedded
+applications.  There are no standard Unix configurations.
+This configuration
+corresponds to AMD's standard calling sequence and binary interface
+and is compatible with other 29k tools.
+
+You may need to make a variant of the file @file{a29k.h} for your
+particular configuration.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{a29k-*-bsd}a29k-*-bsd
+AMD Am29050 used in a system running a variant of BSD Unix.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{alpha*-*-*}alpha*-*-*
+
+This section contains general configuration information for all
+alpha-based platforms using ELF (in particular, ignore this section for
+DEC OSF/1, Digital UNIX and Tru64 UNIX)@.  In addition to reading this
+section, please read all other sections that match your target.
+
+We require binutils 2.11.2 or newer.
+Previous binutils releases had a number of problems with DWARF 2
+debugging information, not the least of which is incorrect linking of
+shared libraries.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{alpha*-dec-osf*}alpha*-dec-osf*
+Systems using processors that implement the DEC Alpha architecture and
+are running the DEC/Compaq Unix (DEC OSF/1, Digital UNIX, or Compaq
+Tru64 UNIX) operating system, for example the DEC Alpha AXP systems.
+
+In Tru64 UNIX V5.1, Compaq introduced a new assembler that does not
+currently (2001-06-13) work with @command{mips-tfile}.  As a workaround,
+we need to use the old assembler, invoked via the barely documented
+@option{-oldas} option.  To bootstrap GCC, you either need to use the
+Compaq C Compiler:
+
+@example
+   % CC=cc @var{srcdir}/configure [@var{options}] [@var{target}]
+@end example
+
+or you can use a copy of GCC 2.95.3 or higher built on Tru64 UNIX V4.0:
+
+@example
+   % CC=gcc -Wa,-oldas @var{srcdir}/configure [@var{options}] [@var{target}]
+@end example
+
+As of GNU binutils 2.11.2, neither GNU @command{as} nor GNU @command{ld}
+are supported on Tru64 UNIX, so you must not configure GCC with
+@option{--with-gnu-as} or @option{--with-gnu-ld}.
+
+The @option{--enable-threads} options isn't supported yet.  A patch is
+in preparation for a future release.  The Java runtime library has been
+reported to work on Tru64 UNIX V4.0F, V5.0, and V5.1, so you may try
+@option{--enable-libgcj} and report your results.
+
+GCC writes a @samp{.verstamp} directive to the assembler output file
+unless it is built as a cross-compiler.  It gets the version to use from
+the system header file @file{/usr/include/stamp.h}.  If you install a
+new version of DEC Unix, you should rebuild GCC to pick up the new version
+stamp.
+
+Note that since the Alpha is a 64-bit architecture, cross-compilers from
+32-bit machines will not generate code as efficient as that generated
+when the compiler is running on a 64-bit machine because many
+optimizations that depend on being able to represent a word on the
+target in an integral value on the host cannot be performed.  Building
+cross-compilers on the Alpha for 32-bit machines has only been tested in
+a few cases and may not work properly.
+
+@code{make compare} may fail on old versions of DEC Unix unless you add
+@option{-save-temps} to @code{CFLAGS}.  On these systems, the name of the
+assembler input file is stored in the object file, and that makes
+comparison fail if it differs between the @code{stage1} and
+@code{stage2} compilations.  The option @option{-save-temps} forces a
+fixed name to be used for the assembler input file, instead of a
+randomly chosen name in @file{/tmp}.  Do not add @option{-save-temps}
+unless the comparisons fail without that option.  If you add
+@option{-save-temps}, you will have to manually delete the @samp{.i} and
+@samp{.s} files after each series of compilations.
+
+GCC now supports both the native (ECOFF) debugging format used by DBX
+and GDB and an encapsulated STABS format for use only with GDB@.  See the
+discussion of the @option{--with-stabs} option of @file{configure} above
+for more information on these formats and how to select them.
+
+There is a bug in DEC's assembler that produces incorrect line numbers
+for ECOFF format when the @samp{.align} directive is used.  To work
+around this problem, GCC will not emit such alignment directives
+while writing ECOFF format debugging information even if optimization is
+being performed.  Unfortunately, this has the very undesirable
+side-effect that code addresses when @option{-O} is specified are
+different depending on whether or not @option{-g} is also specified.
+
+To avoid this behavior, specify @option{-gstabs+} and use GDB instead of
+DBX@.  DEC is now aware of this problem with the assembler and hopes to
+provide a fix shortly.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{alphaev5-cray-unicosmk*}alphaev5-cray-unicosmk*
+Cray T3E systems running Unicos/Mk.
+
+This port is incomplete and has many known bugs.  We hope to improve the
+support for this target soon.  Currently, only the C front end is supported,
+and it is not possible to build parallel applications.  Cray modules are not
+supported; in particular, Craylibs are assumed to be in
+@file{/opt/ctl/craylibs/craylibs}.
+
+You absolutely @strong{must} use GNU make on this platform.  Also, you
+need to tell GCC where to find the assembler and the linker.  The
+simplest way to do so is by providing @option{--with-as} and
+@option{--with-ld} to @file{configure}, e.g.@:
+
+@samp{configure --with-as=/opt/ctl/bin/cam --with-ld=/opt/ctl/bin/cld
+--enable-languages=c}
+
+The comparison test during @samp{make bootstrap} fails on Unicos/Mk
+because the assembler inserts timestamps into object files.  You should
+be able to work around this by doing @samp{make all} after getting this
+failure.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{arc-*-elf}arc-*-elf
+Argonaut ARC processor.
+This configuration is intended for embedded systems.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{arm-*-aout}arm-*-aout
+Advanced RISC Machines ARM-family processors.  These are often used in
+embedded applications.  There are no standard Unix configurations.
+This configuration corresponds to the basic instruction sequences and will
+produce @file{a.out} format object modules.
+
+You may need to make a variant of the file @file{arm.h} for your particular
+configuration.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{arm-*-elf}arm-*-elf
+This configuration is intended for embedded systems.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{arm*-*-linux-gnu}arm*-*-linux-gnu
+
+We require GNU binutils 2.10 or newer.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{arm-*-riscix}arm-*-riscix
+The ARM2 or ARM3 processor running RISC iX, Acorn's port of BSD Unix.
+If you are running a version of RISC iX prior to 1.2 then you must
+specify the version number during configuration.  Note that the
+assembler shipped with RISC iX does not support stabs debugging
+information; a new version of the assembler, with stabs support
+included, is now available from Acorn and via ftp
+@uref{ftp://ftp.acorn.com/pub/riscix/as+xterm.tar.Z}.  To enable stabs
+debugging, pass @option{--with-gnu-as} to configure.
+
+You will need to install GNU @command{sed} before you can run configure.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{avr}avr
+
+ATMEL AVR-family micro controllers.  These are used in embedded
+applications.  There are no standard Unix configurations.
+@ifnothtml
+@xref{AVR Options,, AVR Options, gcc, Using and Porting the GNU Compiler
+Collection (GCC)},
+@end ifnothtml
+@ifhtml
+See ``AVR Options'' in the main manual
+@end ifhtml
+for the list of supported MCU types.
+
+Use @samp{configure --target=avr --enable-languages="c"} to configure GCC@.
+
+Further installation notes and other useful information about AVR tools
+can also be obtained from:
+
+@itemize @bullet
+@item
+@uref{http://home.overta.ru/users/denisc,,http://home.overta.ru/users/denisc}
+@item
+@uref{http://www.itnet.pl/amelektr/avr,,http://www.itnet.pl/amelektr/avr}
+@end itemize
+
+We @emph{strongly} recommend using binutils 2.11 or newer.
+
+The following error:
+@example
+  Error: register required
+@end example
+
+indicates that you should upgrade to a newer version of the binutils.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{c4x}c4x
+
+Texas Instruments TMS320C3x and TMS320C4x Floating Point Digital Signal
+Processors.  These are used in embedded applications.  There are no
+standard Unix configurations.
+@ifnothtml
+@xref{TMS320C3x/C4x Options,, TMS320C3x/C4x Options, gcc, Using and
+Porting the GNU Compiler Collection (GCC)},
+@end ifnothtml
+@ifhtml
+See ``TMS320C3x/C4x Options'' in the main manual
+@end ifhtml
+for the list of supported MCU types.
+
+GCC can be configured as a cross compiler for both the C3x and C4x
+architectures on the same system.  Use @samp{configure --target=c4x
+--enable-languages="c,c++"} to configure.
+
+
+Further installation notes and other useful information about C4x tools
+can also be obtained from:
+
+@itemize @bullet
+@item
+@uref{http://www.elec.canterbury.ac.nz/c4x/,,http://www.elec.canterbury.ac.nz/c4x/}
+@end itemize
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{cris}CRIS
+
+CRIS is the CPU architecture in Axis Communications ETRAX system-on-a-chip
+series.  These are used in embedded applications.
+
+@ifnothtml
+@xref{CRIS Options,, CRIS Options, gcc, Using and Porting the GNU Compiler
+Collection (GCC)},
+@end ifnothtml
+@ifhtml
+See ``CRIS Options'' in the main manual
+@end ifhtml
+for a list of CRIS-specific options.
+
+There are a few different CRIS targets:
+@table @code
+@item cris-axis-aout
+Old target.  Includes a multilib for the @samp{elinux} a.out-based
+target.  No multilibs for newer architecture variants.
+@item cris-axis-elf
+Mainly for monolithic embedded systems.  Includes a multilib for the
+@samp{v10} core used in @samp{ETRAX 100 LX}.
+@item cris-axis-linux-gnu
+A GNU/Linux port for the CRIS architecture, currently targeting
+@samp{ETRAX 100 LX} by default.
+@end table
+
+For @code{cris-axis-aout} and @code{cris-axis-elf} you need binutils 2.11
+or newer.  For @code{cris-axis-linux-gnu} you need binutils 2.12 or newer.
+
+Pre-packaged tools can be obtained from
+@uref{ftp://ftp.axis.com/pub/axis/tools/cris/compiler-kit/}.  More
+information about this platform is available at
+@uref{http://developer.axis.com/}.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{dos}DOS
+
+Please have a look at our @uref{binaries.html,,binaries page}.
+
+You cannot install GCC by itself on MSDOS; it will not compile under
+any MSDOS compiler except itself.  You need to get the complete
+compilation package DJGPP, which includes binaries as well as sources,
+and includes all the necessary compilation tools and libraries.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{dsp16xx}dsp16xx
+A port to the AT&T DSP1610 family of processors.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{*-*-freebsd*}*-*-freebsd*
+
+The version of binutils installed in @file{/usr/bin} is known to work unless
+otherwise specified in any per-architecture notes.  However, binutils
+2.11 is known to improve overall testsuite results.
+
+For FreeBSD 1, FreeBSD 2 or any mutant a.out versions of FreeBSD 3: All
+configuration support and files as shipped with GCC 2.95 are still in
+place.  FreeBSD 2.2.7 has been known to bootstrap completely; however,
+it is unknown which version of binutils was used (it is assumed that it
+was the system copy in @file{/usr/bin}) and C++ EH failures were noted.
+
+For FreeBSD using the ELF file format: DWARF 2 debugging is now the
+default for all CPU architectures.  It had been the default on
+FreeBSD/alpha since its inception.  You may use @option{-gstabs} instead
+of @option{-g}, if you really want the old debugging format.  There are
+no known issues with mixing object files and libraries with different
+debugging formats.  Otherwise, this release of GCC should now match more
+of the configuration used in the stock FreeBSD configuration of GCC.  In
+particular, @option{--enable-threads} is now configured by default.
+However, as a general user, do not attempt to replace the system
+compiler with this release.  Known to bootstrap and check with good
+results on FreeBSD 3.0, 3.4, 4.0, 4.2, 4.3 and 5-CURRENT@.
+
+At this time, @option{--enable-threads} is not compatible with
+@option{--enable-libgcj} on FreeBSD@.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{elxsi-elxsi-bsd}elxsi-elxsi-bsd
+The Elxsi's C compiler has known limitations that prevent it from
+compiling GCC@.  Please contact @email{mrs@@wrs.com} for more details.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{h8300-hms}h8300-hms
+Hitachi H8/300 series of processors.
+
+Please have a look at our @uref{binaries.html,,binaries page}.
+
+The calling convention and structure layout has changed in release 2.6.
+All code must be recompiled.  The calling convention now passes the
+first three arguments in function calls in registers.  Structures are no
+longer a multiple of 2 bytes.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{hppa*-hp-hpux*}hppa*-hp-hpux*
+
+We @emph{highly} recommend using gas/binutils 2.8 or newer on all hppa
+platforms; you may encounter a variety of problems when using the HP
+assembler.
+
+Specifically, @option{-g} does not work on HP-UX (since that system
+uses a peculiar debugging format which GCC does not know about), unless you
+use GAS and GDB and configure GCC with the
+@uref{./configure.html#with-gnu-as,,@option{--with-gnu-as}} and
+@option{--with-as=@dots{}} options.
+
+If you wish to use pa-risc 2.0 architecture support, you must use either
+the HP assembler, gas/binutils 2.11 or a recent
+@uref{ftp://sources.redhat.com/pub/binutils/snapshots,,snapshot of gas}.
+
+More specific information to @samp{hppa*-hp-hpux*} targets follows.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{hppa*-hp-hpux9}hppa*-hp-hpux9
+
+The HP assembler has major problems on this platform.  We've tried to work
+around the worst of the problems.  However, those workarounds may be causing
+linker crashes in some circumstances; the workarounds also probably prevent
+shared libraries from working.  Use the GNU assembler to avoid these problems.
+
+
+The configuration scripts for GCC will also trigger a bug in the hpux9
+shell.  To avoid this problem set @env{CONFIG_SHELL} to @file{/bin/ksh}
+and @env{SHELL} to @file{/bin/ksh} in your environment.
+
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{hppa*-hp-hpux10}hppa*-hp-hpux10
+
+For hpux10.20, we @emph{highly} recommend you pick up the latest sed patch
+@code{PHCO_19798} from HP@.  HP has two sites which provide patches free of
+charge:
+
+@itemize @bullet
+@item
+@html
+<a href="http://us-support.external.hp.com">US, Canada, Asia-Pacific, and
+Latin-America</a>
+@end html
+@ifnothtml
+@uref{http://us-support.external.hp.com,,}US, Canada, Asia-Pacific, and
+Latin-America
+@end ifnothtml
+@item
+@uref{http://europe-support.external.hp.com,,Europe}
+@end itemize
+
+The HP assembler on these systems is much better than the hpux9 assembler,
+but still has some problems.  Most notably the assembler inserts timestamps
+into each object file it creates, causing the 3-stage comparison test to fail
+during a @samp{make bootstrap}.  You should be able to continue by
+saying @samp{make all} after getting the failure from @samp{make
+bootstrap}.
+
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{hppa*-hp-hpux11}hppa*-hp-hpux11
+
+GCC 3.0 supports HP-UX 11.  You must use GNU binutils 2.11 or above on
+this platform.  Thread support is not currently implemented for this 
+platform, so @option{--enable-threads} does not work.
+See @uref{http://gcc.gnu.org/ml/gcc-prs/2002-01/msg00551.html}
+and @uref{http://gcc.gnu.org/ml/gcc-bugs/2002-01/msg00663.html}.
+GCC 2.95.x is not supported under HP-UX 11 and cannot be used to
+compile GCC 3.0.  Refer to @uref{binaries.html,,binaries} for information
+about obtaining precompiled GCC binaries for HP-UX.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{i370-*-*}i370-*-*
+This port is very preliminary and has many known bugs.  We hope to
+have a higher-quality port for this machine soon.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{*-*-linux-gnu}*-*-linux-gnu
+
+If you use glibc 2.2 (or 2.1.9x), GCC 2.95.2 won't install
+out-of-the-box.  You'll get compile errors while building @samp{libstdc++}.
+The patch @uref{glibc-2.2.patch,,glibc-2.2.patch}, that is to be
+applied in the GCC source tree, fixes the compatibility problems.
+
+@html
+</p>
+@end html
+
+@html
+<p>
+@end html
+
+Currently Glibc 2.2.3 (and older releases) and GCC 3.0 are out of sync
+since the latest exception handling changes for GCC@.  Compiling glibc
+with GCC 3.0 will give a binary incompatible glibc and therefore cause
+lots of problems and might make your system completly unusable.  This
+will definitly need fixes in glibc but might also need fixes in GCC@.  We
+strongly advise to wait for glibc 2.2.4 and to read the release notes of
+glibc 2.2.4 whether patches for GCC 3.0 are needed.  You can use glibc
+2.2.3 with GCC 3.0, just do not try to recompile it.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ix86-*-linux*oldld}i?86-*-linux*oldld
+Use this configuration to generate @file{a.out} binaries on Linux-based
+GNU systems if you do not have gas/binutils version 2.5.2 or later
+installed.  This is an obsolete configuration.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ix86-*-linux*aout}i?86-*-linux*aout
+Use this configuration to generate @file{a.out} binaries on Linux-based
+GNU systems.  This configuration is being superseded.  You must use
+gas/binutils version 2.5.2 or later.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ix86-*-linux*}i?86-*-linux*
+
+You will need binutils 2.9.1.0.15 or newer for exception handling to work.
+
+If you receive Signal 11 errors when building on GNU/Linux, then it is
+possible you have a hardware problem.  Further information on this can be
+found on @uref{http://www.bitwizard.nl/sig11/,,www.bitwizard.nl}.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ix86-*-sco}i?86-*-sco
+Compilation with RCC is recommended.  Also, it may be a good idea to
+link with GNU malloc instead of the malloc that comes with the system.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ix86-*-sco3.2v4}i?86-*-sco3.2v4
+Use this configuration for SCO release 3.2 version 4.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ix86-*-sco3.2v5*}i?86-*-sco3.2v5*
+Use this for the SCO OpenServer Release 5 family of operating systems.
+
+Unlike earlier versions of GCC, the ability to generate COFF with this
+target is no longer provided.
+
+Earlier versions of GCC emitted DWARF 1 when generating ELF to allow
+the system debugger to be used.  That support was too burdensome to
+maintain.  GCC now emits only DWARF 2 for this target.  This means you
+may use either the UDK debugger or GDB to debug programs built by this
+version of GCC@.
+
+Use of the @option{-march=pentiumpro} flag can result in
+unrecognized opcodes when using the native assembler on OS versions before
+5.0.6.  (Support for P6 opcodes was added to the native ELF assembler in
+that version.)  While it's rather rare to see these emitted by GCC yet,
+errors of the basic form:
+
+@example
+  /usr/tmp/ccaNlqBc.s:22:unknown instruction: fcomip
+  /usr/tmp/ccaNlqBc.s:50:unknown instruction: fucomip
+@end example
+
+are symptoms of this problem.  You may work around this by not
+building affected files with that flag, by using the GNU assembler, or
+by using the assembler provided with the current version of the OS@.
+Users of GNU assembler should see the note below for hazards on doing
+so.
+
+The native SCO assembler that is provided with the OS at no
+charge is normally required.  If, however, you must be able to use
+the GNU assembler (perhaps you're compiling code with asms that
+require GAS syntax) you may configure this package using the flags
+@uref{./configure.html#with-gnu-as,,@option{--with-gnu-as}}.  You must
+use a recent version of GNU binutils; versions past 2.9.1 seem to work
+well.
+
+In general, the @option{--with-gnu-as} option isn't as well tested
+as the native assembler.
+
+Look in @file{gcc/config/i386/sco5.h} (search for ``messy'') for
+additional OpenServer-specific flags.
+
+Systems based on OpenServer before 5.0.4 (@samp{uname -X}
+will tell you what you're running) require TLS597 from
+@uref{ftp://ftp.sco.com/TLS/,,ftp://ftp.sco.com/TLS/}
+for C++ constructors and destructors to work right.
+
+The system linker in (at least) 5.0.4 and 5.0.5 will sometimes
+do the wrong thing for a construct that GCC will emit for PIC
+code.  This can be seen as execution testsuite failures when using
+@option{-fPIC} on @file{921215-1.c}, @file{931002-1.c}, @file{nestfunc-1.c}, and @file{gcov-1.c}.
+For 5.0.5, an updated linker that will cure this problem is
+available.  You must install both
+@uref{ftp://ftp.sco.com/Supplements/rs505a/,,ftp://ftp.sco.com/Supplements/rs505a/}
+and @uref{ftp://ftp.sco.com/SLS/,,OSS499A}.
+
+The dynamic linker in OpenServer 5.0.5 (earlier versions may show
+the same problem) aborts on certain G77-compiled programs.  It's particularly
+likely to be triggered by building Fortran code with the @option{-fPIC} flag.
+Although it's conceivable that the error could be triggered by other
+code, only G77-compiled code has been observed to cause this abort.
+If you are getting core dumps immediately upon execution of your
+G77 program---and especially if it's compiled with @option{-fPIC}---try applying
+@uref{sco_osr5_g77.patch,,@file{sco_osr5_g77.patch}} to your @samp{libf2c} and
+rebuilding GCC@.
+Affected faults, when analyzed in a debugger, will show a stack
+backtrace with a fault occurring in @code{rtld()} and the program
+running as @file{/usr/lib/ld.so.1}.  This problem has been reported to SCO
+engineering and will hopefully be addressed in later releases.
+
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ix86-*-udk}i?86-*-udk
+
+This target emulates the SCO Universal Development Kit and requires that
+package be installed.  (If it is installed, you will have a
+@file{/udk/usr/ccs/bin/cc} file present.)  It's very much like the
+@samp{i?86-*-unixware7*} target
+but is meant to be used when hosting on a system where UDK isn't the
+default compiler such as OpenServer 5 or Unixware 2.  This target will
+generate binaries that will run on OpenServer, Unixware 2, or Unixware 7,
+with the same warnings and caveats as the SCO UDK@.
+
+This target is a little tricky to build because we have to distinguish
+it from the native tools (so it gets headers, startups, and libraries
+from the right place) while making the tools not think we're actually
+building a cross compiler.   The easiest way to do this is with a configure
+command like this:
+
+@samp{CC=/udk/usr/ccs/bin/cc @var{/your/path/to}/gcc/configure
+--host=i686-pc-udk --target=i686-pc-udk --program-prefix=udk-}
+
+@emph{You should substitute @samp{i686} in the above command with the appropriate
+processor for your host.}
+
+After the usual @samp{make bootstrap} and
+@samp{make install}, you can then access the UDK-targeted GCC
+tools by adding @command{udk-} before the commonly known name.  For
+example, to invoke the C compiler, you would use @command{udk-gcc}.
+They will coexist peacefully with any native-target GCC tools you may
+have installed.
+
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ix86-*-isc}i?86-*-isc
+It may be a good idea to link with GNU malloc instead of the malloc that
+comes with the system.
+
+In ISC version 4.1, @command{sed} core dumps when building
+@file{deduced.h}.  Use the version of @command{sed} from version 4.0.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ix86-*-esix}i?86-*-esix
+It may be good idea to link with GNU malloc instead of the malloc that
+comes with the system.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ix86-ibm-aix}i?86-ibm-aix
+You need to use GAS version 2.1 or later, and LD from
+GNU binutils version 2.2 or later.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ix86-sequent-bsd}i?86-sequent-bsd
+Go to the Berkeley universe before compiling.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ix86-sequent-ptx1*}i?86-sequent-ptx1*, i?86-sequent-ptx2*
+You must install GNU @command{sed} before running @command{configure}.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{#ix86-*-sysv3*}i?86-*-sysv3*
+The @code{fixproto} shell script may trigger a bug in the system shell.
+If you encounter this problem, upgrade your operating system or
+use @command{bash} (the GNU shell) to run @code{fixproto}.
+
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{i860-intel-osf*}i860-intel-osf*
+On the Intel Paragon (an i860 machine), if you are using operating
+system version 1.0, you will get warnings or errors about redefinition
+of @code{va_arg} when you build GCC@.
+
+If this happens, then you need to link most programs with the library
+@file{iclib.a}.  You must also modify @file{stdio.h} as follows: before
+the lines
+
+@example
+#if     defined(__i860__) && !defined(_VA_LIST)
+#include <va_list.h>
+@end example
+
+@noindent
+insert the line
+
+@example
+#if __PGC__
+@end example
+
+@noindent
+and after the lines
+
+@example
+extern int  vprintf(const char *, va_list );
+extern int  vsprintf(char *, const char *, va_list );
+#endif
+@end example
+
+@noindent
+insert the line
+
+@example
+#endif /* __PGC__ */
+@end example
+
+These problems don't exist in operating system version 1.1.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ia64-*-linux}ia64-*-linux
+IA-64 processor (also known as IPF, or Itanium Processor Family)
+running GNU/Linux.
+
+The toolchain is not completely finished, so requirements will continue
+to change.
+GCC 3.0.1 and later require glibc 2.2.4.
+GCC 3.0.2 requires binutils from 2001-09-05 or later.
+GCC 3.0.1 requires binutils 2.11.1 or later.
+
+None of the following versions of GCC has an ABI that is compatible
+with any of the other versions in this list, with the exception that
+Red Hat 2.96 and Trillian 000171 are compatible with each other:
+3.0.2, 3.0.1, 3.0, Red Hat 2.96, and Trillian 000717.
+This primarily affects C++ programs and programs that create shared libraries.
+Because of these ABI incompatibilities, GCC 3.0.2 is not recommended for
+user programs on GNU/Linux systems built using earlier compiler releases.
+GCC 3.0.2 is recommended for compiling linux, the kernel.
+GCC 3.0.2 is believed to be fully ABI compliant, and hence no more major
+ABI changes are expected.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{*-lynx-lynxos}*-lynx-lynxos
+LynxOS 2.2 and earlier comes with GCC 1.x already installed as
+@file{/bin/gcc}.  You should compile with this instead of @file{/bin/cc}.
+You can tell GCC to use the GNU assembler and linker, by specifying
+@samp{--with-gnu-as --with-gnu-ld} when configuring.  These will produce
+COFF format object files and executables;  otherwise GCC will use the
+installed tools, which produce @file{a.out} format executables.
+
+@html
+</p>
+<hr>
+<!-- rs6000-ibm-aix*, powerpc-ibm-aix* -->
+@end html
+@heading @anchor{*-ibm-aix*}*-ibm-aix*
+
+AIX Make frequently has problems with GCC makefiles.  GNU Make 3.76 or
+newer is recommended to build on this platform.
+
+Errors involving @code{alloca} when building GCC generally are due
+to an incorrect definition of @code{CC} in the Makefile or mixing files
+compiled with the native C compiler and GCC@.  During the stage1 phase of
+the build, the native AIX compiler @strong{must} be invoked as @command{cc}
+(not @command{xlc}).  Once @command{configure} has been informed of
+@command{xlc}, one needs to use @samp{make distclean} to remove the
+configure cache files and ensure that @env{CC} environment variable
+does not provide a definition that will confuse @command{configure}.
+If this error occurs during stage2 or later, then the problem most likely
+is the version of Make (see above).
+
+The GNU Assembler incorrectly reports that it supports WEAK symbols on
+AIX which causes GCC to try to utilize weak symbol functionality which
+is not really supported on the platform.  The native @command{as} and
+@command{ld} still are recommended.  The native AIX tools do
+interoperate with GCC@.
+
+Building @file{libstdc++.a} requires a fix for a AIX Assembler bug
+APAR IY26685 (AIX 4.3) or APAR IY25528 (AIX 5.1).
+
+Linking executables and shared libraries may produce warnings of
+duplicate symbols.  The assembly files generated by GCC for AIX always
+have included multiple symbol definitions for certain global variable
+and function declarations in the original program.  The warnings should
+not prevent the linker from producing a correct library or runnable
+executable.
+
+AIX 4.3 utilizes a ``large format'' archive to support both 32-bit and
+64-bit object modules.  The routines provided in AIX 4.3.0 and AIX 4.3.1
+to parse archive libraries did not handle the new format correctly.
+These routines are used by GCC and result in error messages during
+linking such as ``not a COFF file''.  The version of the routines shipped
+with AIX 4.3.1 should work for a 32-bit environment.  The @option{-g}
+option of the archive command may be used to create archives of 32-bit
+objects using the original ``small format''.  A correct version of the
+routines is shipped with AIX 4.3.2 and above.
+
+Some versions of the AIX binder (linker) can fail with a relocation
+overflow severe error when the @option{-bbigtoc} option is used to link
+GCC-produced object files into an executable that overflows the TOC@.  A fix
+for APAR IX75823 (OVERFLOW DURING LINK WHEN USING GCC AND -BBIGTOC) is
+available from IBM Customer Support and from its
+@uref{http://techsupport.services.ibm.com/,,techsupport.services.ibm.com}
+website as PTF U455193.
+
+The AIX 4.3.2.1 linker (bos.rte.bind_cmds Level 4.3.2.1) will dump core
+with a segmentation fault when invoked by any version of GCC@.  A fix for
+APAR IX87327 is available from IBM Customer Support and from its
+@uref{http://techsupport.services.ibm.com/,,techsupport.services.ibm.com}
+website as PTF U461879.  This fix is incorporated in AIX 4.3.3 and above.
+
+The initial assembler shipped with AIX 4.3.0 generates incorrect object
+files.  A fix for APAR IX74254 (64BIT DISASSEMBLED OUTPUT FROM COMPILER FAILS
+TO ASSEMBLE/BIND) is available from IBM Customer Support and from its
+@uref{http://techsupport.services.ibm.com/,,techsupport.services.ibm.com}
+website as PTF U453956.  This fix is incorporated in AIX 4.3.1 and above.
+
+AIX provides National Language Support (NLS)@.  Compilers and assemblers
+use NLS to support locale-specific representations of various data
+formats including floating-point numbers (e.g., @samp{.}  vs @samp{,} for
+separating decimal fractions).  There have been problems reported where
+GCC does not produce the same floating-point formats that the assembler
+expects.  If one encounters this problem, set the @env{LANG}
+environment variable to @samp{C} or @samp{En_US}.
+
+By default, GCC for AIX 4.1 and above produces code that can be used on
+both Power or PowerPC processors.
+
+A default can be specified with the @option{-mcpu=@var{cpu_type}}
+switch and using the configure option @option{--with-cpu-@var{cpu_type}}.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m32r-*-elf}m32r-*-elf
+Mitsubishi M32R processor.
+This configuration is intended for embedded systems.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m68000-hp-bsd}m68000-hp-bsd
+HP 9000 series 200 running BSD@.  Note that the C compiler that comes
+with this system cannot compile GCC; contact @email{law@@cygnus.com}
+to get binaries of GCC for bootstrapping.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m6811-elf}m6811-elf
+Motorola 68HC11 family micro controllers.  These are used in embedded
+applications.  There are no standard Unix configurations.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m6812-elf}m6812-elf
+Motorola 68HC12 family micro controllers.  These are used in embedded
+applications.  There are no standard Unix configurations.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m68k-altos}m68k-altos
+Altos 3068.  You must use the GNU assembler, linker and debugger.
+Also, you must fix a kernel bug.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m68k-apple-aux}m68k-apple-aux
+Apple Macintosh running A/UX@.
+You may configure GCC  to use either the system assembler and
+linker or the GNU assembler and linker.  You should use the GNU configuration
+if you can, especially if you also want to use G++.  You enable
+that configuration with the @option{--with-gnu-as} and @option{--with-gnu-ld}
+options to @code{configure}.
+
+Note the C compiler that comes
+with this system cannot compile GCC@.  You can find binaries of GCC
+for bootstrapping on @code{jagubox.gsfc.nasa.gov}.
+You will also a patched version of @file{/bin/ld} there that
+raises some of the arbitrary limits found in the original.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m68k-att-sysv}m68k-att-sysv
+AT&T 3b1, a.k.a.@: 7300 PC@.  This version of GCC cannot
+be compiled with the system C compiler, which is too buggy.
+You will need to get a previous version of GCC and use it to
+bootstrap.  Binaries are available from the OSU-CIS archive, at
+@uref{ftp://archive.cis.ohio-state.edu/pub/att7300/}.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m68k-bull-sysv}m68k-bull-sysv
+Bull DPX/2 series 200 and 300 with BOS-2.00.45 up to BOS-2.01.  GCC works
+either with native assembler or GNU assembler.  You can use
+GNU assembler with native COFF generation by providing @option{--with-gnu-as} to
+the configure script or use GNU assembler with stabs-in-COFF encapsulation
+by providing @samp{--with-gnu-as --stabs}.  For any problem with the native
+assembler or for availability of the DPX/2 port of GAS, contact
+@email{F.Pierresteguy@@frcl.bull.fr}.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m68k-crds-unox}m68k-crds-unox
+Use @samp{configure unos} for building on Unos.
+
+The Unos assembler is named @code{casm} instead of @code{as}.  For some
+strange reason linking @file{/bin/as} to @file{/bin/casm} changes the
+behavior, and does not work.  So, when installing GCC, you should
+install the following script as @file{as} in the subdirectory where
+the passes of GCC are installed:
+
+@example
+#!/bin/sh
+casm $*
+@end example
+
+The default Unos library is named @file{libunos.a} instead of
+@file{libc.a}.  To allow GCC to function, either change all
+references to @option{-lc} in @file{gcc.c} to @option{-lunos} or link
+@file{/lib/libc.a} to @file{/lib/libunos.a}.
+
+@cindex @code{alloca}, for Unos
+When compiling GCC with the standard compiler, to overcome bugs in
+the support of @code{alloca}, do not use @option{-O} when making stage 2.
+Then use the stage 2 compiler with @option{-O} to make the stage 3
+compiler.  This compiler will have the same characteristics as the usual
+stage 2 compiler on other systems.  Use it to make a stage 4 compiler
+and compare that with stage 3 to verify proper compilation.
+
+(Perhaps simply defining @code{ALLOCA} in @file{x-crds} as described in
+the comments there will make the above paragraph superfluous.  Please
+inform us of whether this works.)
+
+Unos uses memory segmentation instead of demand paging, so you will need
+a lot of memory.  5 Mb is barely enough if no other tasks are running.
+If linking @file{cc1} fails, try putting the object files into a library
+and linking from that library.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m68k-hp-hpux}m68k-hp-hpux
+HP 9000 series 300 or 400 running HP-UX@.  HP-UX version 8.0 has a bug in
+the assembler that prevents compilation of GCC@.  This
+bug manifests itself during the first stage of compilation, while
+building @file{libgcc2.a}:
+
+@smallexample
+_floatdisf
+cc1: warning: `-g' option not supported on this version of GCC
+cc1: warning: `-g1' option not supported on this version of GCC
+./xgcc: Internal compiler error: program as got fatal signal 11
+@end smallexample
+
+A patched version of the assembler is available as the file
+@uref{ftp://altdorf.ai.mit.edu/archive/cph/hpux-8.0-assembler}.  If you
+have HP software support, the patch can also be obtained directly from
+HP, as described in the following note:
+
+@quotation
+This is the patched assembler, to patch SR#1653-010439, where the
+assembler aborts on floating point constants.
+
+The bug is not really in the assembler, but in the shared library
+version of the function ``cvtnum(3c)''.  The bug on ``cvtnum(3c)'' is
+SR#4701-078451.  Anyway, the attached assembler uses the archive
+library version of ``cvtnum(3c)'' and thus does not exhibit the bug.
+@end quotation
+
+This patch is also known as PHCO_4484.
+
+In addition, if you wish to use gas, you must use
+gas version 2.1 or later, and you must use the GNU linker version 2.1 or
+later.  Earlier versions of gas relied upon a program which converted the
+gas output into the native HP-UX format, but that program has not been
+kept up to date.  gdb does not understand that native HP-UX format, so
+you must use gas if you wish to use gdb.
+
+On HP-UX version 8.05, but not on 8.07 or more recent versions, the
+@code{fixproto} shell script triggers a bug in the system shell.  If you
+encounter this problem, upgrade your operating system or use BASH (the
+GNU shell) to run @code{fixproto}.  This bug will cause the fixproto
+program to report an error of the form:
+
+@example
+./fixproto: sh internal 1K buffer overflow
+@end example
+
+To fix this, you can also change the first line of the fixproto script
+to look like:
+
+@example
+#!/bin/ksh
+@end example
+
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m68k-*-nextstep*}m68k-*-nextstep*
+
+Current GCC versions probably do not work on version 2 of the NeXT
+operating system.
+
+On NeXTStep 3.0, the Objective-C compiler does not work, due,
+apparently, to a kernel bug that it happens to trigger.  This problem
+does not happen on 3.1.
+
+You absolutely @strong{must} use GNU sed and GNU make on this platform.
+
+
+On NeXTSTEP 3.x where x < 3 the build of GCC will abort during  
+stage1 with an error message like this:
+
+@example
+  _eh
+  /usr/tmp/ccbbsZ0U.s:987:Unknown pseudo-op: .section
+  /usr/tmp/ccbbsZ0U.s:987:Rest of line ignored. 1st junk character
+  valued 95 (_).
+@end example
+
+The reason for this is the fact that NeXT's assembler for these
+versions of the operating system does not support the @samp{.section}
+pseudo op that's needed for full C++ exception functionality.
+
+As NeXT's assembler is a derived work from GNU as, a free
+replacement that does can be obtained at
+@uref{ftp://ftp.next.peak.org:/next-ftp/next/apps/devtools/as.3.3.NIHS.s.tar.gz,,ftp://ftp.next.peak.org:/next-ftp/next/apps/devtools/as.3.3.NIHS.s.tar.gz}.
+
+If you try to build the integrated C++ & C++ runtime libraries on this system
+you will run into trouble with include files.  The way to get around this is
+to use the following sequence.  Note you must have write permission to
+the directory @var{prefix} you specified in the configuration process of GCC
+for this sequence to work.
+
+@example
+  cd bld-gcc
+  make all-texinfo all-bison all-byacc all-binutils all-gas all-ld
+  cd gcc
+  make bootstrap
+  make install-headers-tar
+  cd ..
+  make bootstrap3
+@end example
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m68k-ncr-*}m68k-ncr-*
+On the Tower models 4@var{n}0 and 6@var{n}0, by default a process is not
+allowed to have more than one megabyte of memory.  GCC cannot compile
+itself (or many other programs) with @option{-O} in that much memory.
+
+To solve this problem, reconfigure the kernel adding the following line
+to the configuration file:
+
+@smallexample
+MAXUMEM = 4096
+@end smallexample
+
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m68k-sun}m68k-sun
+Sun 3.  We do not provide a configuration file to use the Sun FPA by
+default, because programs that establish signal handlers for floating
+point traps inherently cannot work with the FPA@.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m68k-sun-sunos4.1.1}m68k-sun-sunos4.1.1
+
+It is reported that you may need the GNU assembler on this platform.
+
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m88k-*-svr3}m88k-*-svr3
+Motorola m88k running the AT&T/Unisoft/Motorola V.3 reference port.
+These systems tend to use the Green Hills C, revision 1.8.5, as the
+standard C compiler.  There are apparently bugs in this compiler that
+result in object files differences between stage 2 and stage 3.  If this
+happens, make the stage 4 compiler and compare it to the stage 3
+compiler.  If the stage 3 and stage 4 object files are identical, this
+suggests you encountered a problem with the standard C compiler; the
+stage 3 and 4 compilers may be usable.
+
+It is best, however, to use an older version of GCC for bootstrapping
+if you have one.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m88k-*-dgux}m88k-*-dgux
+Motorola m88k running DG/UX@.  To build 88open BCS native or cross
+compilers on DG/UX, specify the configuration name as
+@samp{m88k-*-dguxbcs} and build in the 88open BCS software development
+environment.  To build ELF native or cross compilers on DG/UX, specify
+@samp{m88k-*-dgux} and build in the DG/UX ELF development environment.
+You set the software development environment by issuing
+@samp{sde-target} command and specifying either @samp{m88kbcs} or
+@samp{m88kdguxelf} as the operand.
+
+If you do not specify a configuration name, @file{configure} guesses the
+configuration based on the current software development environment.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{m88k-tektronix-sysv3}m88k-tektronix-sysv3
+Tektronix XD88 running UTekV 3.2e.  Do not turn on
+optimization while building stage1 if you bootstrap with
+the buggy Green Hills compiler.  Also, the bundled LAI
+System V NFS is buggy so if you build in an NFS mounted
+directory, start from a fresh reboot, or avoid NFS all together.
+Otherwise you may have trouble getting clean comparisons
+between stages.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{mips-*-*}mips-*-*
+If you use the 1.31 version of the MIPS assembler (such as was shipped
+with Ultrix 3.1), you will need to use the @option{-fno-delayed-branch} switch
+when optimizing floating point code.  Otherwise, the assembler will
+complain when the GCC compiler fills a branch delay slot with a
+floating point instruction, such as @code{add.d}.
+
+If on a MIPS system you get an error message saying ``does not have gp
+sections for all it's [sic] sectons [sic]'', don't worry about it.  This
+happens whenever you use GAS with the MIPS linker, but there is not
+really anything wrong, and it is okay to use the output file.  You can
+stop such warnings by installing the GNU linker.
+
+It would be nice to extend GAS to produce the gp tables, but they are
+optional, and there should not be a warning about their absence.
+
+Users have reported some problems with version 2.0 of the MIPS
+compiler tools that were shipped with Ultrix 4.1.  Version 2.10
+which came with Ultrix 4.2 seems to work fine.
+
+Users have also reported some problems with version 2.20 of the
+MIPS compiler tools that were shipped with RISC/os 4.x.  The earlier
+version 2.11 seems to work fine.
+
+Some versions of the MIPS linker will issue an assertion failure
+when linking code that uses @code{alloca} against shared
+libraries on RISC-OS 5.0, and DEC's OSF/1 systems.  This is a bug
+in the linker, that is supposed to be fixed in future revisions.
+To protect against this, GCC passes @option{-non_shared} to the
+linker unless you pass an explicit @option{-shared} or
+@option{-call_shared} switch.
+
+@heading @anchor{mips-mips-bsd}mips-mips-bsd
+MIPS machines running the MIPS operating system in BSD mode.  It's
+possible that some old versions of the system lack the functions
+@code{memcpy}, @code{memmove}, @code{memcmp}, and @code{memset}.  If your
+system lacks these, you must remove or undo the definition of
+@code{TARGET_MEM_FUNCTIONS} in @file{mips-bsd.h}.
+
+If you use the MIPS C compiler to bootstrap, it may be necessary
+to increase its table size for switch statements with the
+@option{-Wf,-XNg1500} option.  If you use the @option{-O2}
+optimization option, you also need to use @option{-Olimit 3000}.
+Both of these options are automatically generated in the
+@file{Makefile} that the shell script @file{configure} builds.
+If you override the @code{CC} make variable and use the MIPS
+compilers, you may need to add @option{-Wf,-XNg1500 -Olimit 3000}.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{mips-dec-*}mips-dec-*
+MIPS-based DECstations can support three different personalities:
+Ultrix, DEC OSF/1, and OSF/rose.  (Alpha-based DECstation products have
+a configuration name beginning with @samp{alpha*-dec}.)  To configure GCC
+for these platforms use the following configurations:
+
+@table @samp
+@item mips-dec-ultrix
+Ultrix configuration.
+
+@item mips-dec-osf1
+DEC's version of OSF/1.
+
+@item mips-dec-osfrose
+Open Software Foundation reference port of OSF/1 which uses the
+OSF/rose object file format instead of ECOFF@.  Normally, you
+would not select this configuration.
+@end table
+
+If you use the MIPS C compiler to bootstrap, it may be necessary
+to increase its table size for switch statements with the
+@option{-Wf,-XNg1500} option.  If you use the @option{-O2}
+optimization option, you also need to use @option{-Olimit 3000}.
+Both of these options are automatically generated in the
+@file{Makefile} that the shell script @file{configure} builds.
+If you override the @code{CC} make variable and use the MIPS
+compilers, you may need to add @option{-Wf,-XNg1500 -Olimit 3000}.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{mips-mips-riscos*}mips-mips-riscos*
+If you use the MIPS C compiler to bootstrap, it may be necessary
+to increase its table size for switch statements with the
+@option{-Wf,-XNg1500} option.  If you use the @option{-O2}
+optimization option, you also need to use @option{-Olimit 3000}.
+Both of these options are automatically generated in the
+@file{Makefile} that the shell script @file{configure} builds.
+If you override the @code{CC} make variable and use the MIPS
+compilers, you may need to add @samp{-Wf,-XNg1500 -Olimit 3000}.
+
+MIPS computers running RISC-OS can support four different
+personalities: default, BSD 4.3, System V.3, and System V.4
+(older versions of RISC-OS don't support V.4).  To configure GCC
+for these platforms use the following configurations:
+
+@table @samp
+@item mips-mips-riscos@var{rev}
+Default configuration for RISC-OS, revision @var{rev}.
+
+@item mips-mips-riscos@var{rev}bsd
+BSD 4.3 configuration for RISC-OS, revision @var{rev}.
+
+@item mips-mips-riscos@var{rev}sysv4
+System V.4 configuration for RISC-OS, revision @var{rev}.
+
+@html
+</p>
+<hr>
+@end html
+@item mips-mips-riscos@var{rev}sysv
+System V.3 configuration for RISC-OS, revision @var{rev}.
+@end table
+
+The revision @code{rev} mentioned above is the revision of
+RISC-OS to use.  You must reconfigure GCC when going from a
+RISC-OS revision 4 to RISC-OS revision 5.  This has the effect of
+avoiding a linker bug.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{mips-sgi-irix4}mips-sgi-irix4
+
+In order to compile GCC on an SGI running IRIX 4, the ``c.hdr.lib''
+option must be installed from the CD-ROM supplied from Silicon Graphics.
+This is found on the 2nd CD in release 4.0.1.
+
+On IRIX version 4.0.5F, and perhaps on some other versions as well,
+there is an assembler bug that reorders instructions incorrectly.  To
+work around it, specify the target configuration
+@samp{mips-sgi-irix4loser}.  This configuration inhibits assembler
+optimization.
+
+In a compiler configured with target @samp{mips-sgi-irix4}, you can turn
+off assembler optimization by using the @option{-noasmopt} option.  This
+compiler option passes the option @option{-O0} to the assembler, to
+inhibit reordering.
+
+The @option{-noasmopt} option can be useful for testing whether a problem
+is due to erroneous assembler reordering.  Even if a problem does not go
+away with @option{-noasmopt}, it may still be due to assembler
+reordering---perhaps GCC itself was miscompiled as a result.
+
+You may get the following warning on IRIX 4 platforms, it can be safely
+ignored.
+@example
+  warning: foo.o does not have gp tables for all its sections.
+@end example
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{mips-sgi-irix5}mips-sgi-irix5
+
+This configuration has considerable problems, which will be fixed in a
+future release.
+
+In order to compile GCC on an SGI running IRIX 5, the ``compiler_dev.hdr''
+subsystem must be installed from the IDO CD-ROM supplied by Silicon
+Graphics.  It is also available for download from
+@uref{http://www.sgi.com/developers/devtools/apis/ido.html,,http://www.sgi.com/developers/devtools/apis/ido.html}.
+
+@code{make compare} may fail on version 5 of IRIX unless you add
+@option{-save-temps} to @code{CFLAGS}.  On these systems, the name of the
+assembler input file is stored in the object file, and that makes
+comparison fail if it differs between the @code{stage1} and
+@code{stage2} compilations.  The option @option{-save-temps} forces a
+fixed name to be used for the assembler input file, instead of a
+randomly chosen name in @file{/tmp}.  Do not add @option{-save-temps}
+unless the comparisons fail without that option.  If you do you
+@option{-save-temps}, you will have to manually delete the @samp{.i} and
+@samp{.s} files after each series of compilations.
+
+If you use the MIPS C compiler to bootstrap, it may be necessary
+to increase its table size for switch statements with the
+@option{-Wf,-XNg1500} option.  If you use the @option{-O2}
+optimization option, you also need to use @option{-Olimit 3000}.
+
+To enable debugging under IRIX 5, you must use GNU @command{as} 2.11.2
+or later, 
+and use the @option{--with-gnu-as} configure option when configuring GCC.
+GNU @command{as} is distributed as part of the binutils package.
+When using release 2.11.2, you need to apply a patch 
+@uref{http://sources.redhat.com/ml/binutils/2001-07/msg00352.html,,http://sources.redhat.com/ml/binutils/2001-07/msg00352.html}
+which will be included in the next release of binutils.
+
+When building GCC, the build process loops rebuilding @command{cc1} over
+and over again.  This happens on @samp{mips-sgi-irix5.2}, and possibly
+other platforms.  It has been reported that this is a known bug in the
+@command{make} shipped with IRIX 5.2.  We recommend you use GNU
+@command{make} instead of the vendor supplied @command{make} program;
+however, you may have success with @command{smake} on IRIX 5.2 if you do
+not have GNU @command{make} available.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{mips-sgi-irix6}mips-sgi-irix6
+
+If you are using IRIX @command{cc} as your bootstrap compiler, you must
+ensure that the N32 ABI is in use.  To test this, compile a simple C
+file with @command{cc} and then run @command{file} on the
+resulting object file.  The output should look like:
+
+@example
+test.o: ELF N32 MSB @dots{}
+@end example
+
+If you see:
+
+@example
+test.o: ELF 32-bit MSB @dots{}
+@end example
+
+or
+
+@example
+test.o: ELF 64-bit MSB @dots{}
+@end example
+
+then your version of @command{cc} uses the O32 or N64 ABI by default.  You
+should set the environment variable @env{CC} to @samp{cc -n32}
+before configuring GCC@.
+
+GCC on IRIX 6 is usually built to support both the N32 and N64 ABIs.  If
+you build GCC on a system that doesn't have the N64 libraries installed,
+you need to configure with @option{--disable-multilib} so GCC doesn't
+try to use them.  Look for @file{/usr/lib64/libc.so.1} to see if you
+have the 64-bit libraries installed.
+
+You must @emph{not} use GNU @command{as} (which isn't built anyway as of
+binutils 2.11.2) on IRIX 6 platforms; doing so will only cause problems.
+
+GCC does not currently support generating O32 ABI binaries in the
+@samp{mips-sgi-irix6} configurations.  It is possible to create a GCC
+with O32 ABI only support by configuring it for the @samp{mips-sgi-irix5}
+target and using a patched GNU @command{as} 2.11.2 as documented in the
+@uref{#mips-sgi-irix5,,@samp{mips-sgi-irix5}} section above.  Using the
+native assembler requires patches to GCC which will be included in a
+future release.  It is
+expected that O32 ABI support will be available again in a future release.
+
+The @option{--enable-threads} option doesn't currently work, a patch is
+in preparation for a future release.  The @option{--enable-libgcj}
+option is disabled by default: IRIX 6 uses a very low default limit
+(20480) for the command line length.  Although libtool contains a
+workaround for this problem, at least the N64 @samp{libgcj} is known not
+to build despite this, running into an internal error of the native
+@command{ld}.  A sure fix is to increase this limit (@samp{ncargs}) to
+its maximum of 262144 bytes.  If you have root access, you can use the
+@command{systune} command to do this.
+
+GCC does not correctly pass/return structures which are
+smaller than 16 bytes and which are not 8 bytes.  The problem is very
+involved and difficult to fix.  It affects a number of other targets also,
+but IRIX 6 is affected the most, because it is a 64 bit target, and 4 byte
+structures are common.  The exact problem is that structures are being padded
+at the wrong end, e.g.@: a 4 byte structure is loaded into the lower 4 bytes
+of the register when it should be loaded into the upper 4 bytes of the
+register.
+
+GCC is consistent with itself, but not consistent with the SGI C compiler
+(and the SGI supplied runtime libraries), so the only failures that can
+happen are when there are library functions that take/return such
+structures. There are very few such library functions.  Currently this
+is known to affect @code{inet_ntoa}, @code{inet_lnaof},
+@code{inet_netof}, @code{inet_makeaddr}, and @code{semctl}.  Until the
+bug is fixed, GCC contains workarounds for the known affected functions.
+
+See @uref{http://freeware.sgi.com/,,http://freeware.sgi.com/} for more
+information about using GCC on IRIX platforms.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{mips-sony-sysv}mips-sony-sysv
+Sony MIPS NEWS@.  This works in NEWSOS 5.0.1, but not in 5.0.2 (which
+uses ELF instead of COFF)@.  Support for 5.0.2 will probably be provided
+soon by volunteers.  In particular, the linker does not like the
+code generated by GCC when shared libraries are linked in.
+
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ns32k-encore}ns32k-encore
+Encore ns32000 system.  Encore systems are supported only under BSD@.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ns32k-*-genix}ns32k-*-genix
+National Semiconductor ns32000 system.  Genix has bugs in @code{alloca}
+and @code{malloc}; you must get the compiled versions of these from GNU
+Emacs.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ns32k-sequent}ns32k-sequent
+Go to the Berkeley universe before compiling.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{ns32k-utek}ns32k-utek
+UTEK ns32000 system (``merlin'').  The C compiler that comes with this
+system cannot compile GCC; contact @samp{tektronix!reed!mason} to get
+binaries of GCC for bootstrapping.
+
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{powerpc*-*-*}powerpc-*-*
+
+You can specify a default version for the @option{-mcpu=@var{cpu_type}}
+switch by using the configure option @option{--with-cpu-@var{cpu_type}}.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{powerpc-*-darwin*}powerpc-*-darwin*
+PowerPC running Darwin (Mac OS X kernel).
+
+GCC 3.0 does not support Darwin, but 3.1 and later releases will work.
+
+Pre-installed versions of Mac OS X may not include any developer tools,
+meaning that you will not be able to build GCC from source.  Tool
+binaries are available at
+@uref{http://www.opensource.apple.com/projects/darwin} (free
+registration required).
+
+Versions of the assembler prior to ``cctools-364'' cannot handle the
+4-argument form of rlwinm and related mask-using instructions.  Darwin
+1.3 (Mac OS X 10.0) uses cctools-353 for instance.  To get cctools-364,
+check out @file{cctools} with tag @samp{Apple-364}, build it, and
+install the assembler as @file{usr/bin/as}.  See
+@uref{http://www.opensource.apple.com/tools/cvs/docs.html} for details.
+
+Also, the default stack limit of 512K is too small, and a bootstrap will
+typically fail when self-compiling @file{expr.c}.  Set the stack to 800K
+or more, for instance by doing @samp{limit stack 800}.  It's also
+convenient to use the GNU preprocessor instead of Apple's during the
+first stage of bootstrapping; this is automatic when doing @samp{make
+bootstrap}, but to do it from the toplevel objdir you will need to say
+@samp{make CC='cc -no-cpp-precomp' bootstrap}.
+
+Note that the version of GCC shipped by Apple typically includes a
+number of extensions not available in a standard GCC release.  These
+extensions are generally specific to Mac programming.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{powerpc-*-elf}powerpc-*-elf, powerpc-*-sysv4
+PowerPC system in big endian mode, running System V.4.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{powerpc-*-linux-gnu*}powerpc-*-linux-gnu*
+
+You will need
+@uref{ftp://ftp.varesearch.com/pub/support/hjl/binutils,,binutils 2.9.4.0.8}
+or newer for a working GCC@.  It is strongly recommended to recompile binutils
+if you initially built it with gcc-2.7.2.x.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{powerpc-*-netbsd*}powerpc-*-netbsd*
+PowerPC system in big endian mode running NetBSD@.  To build the
+documentation you will need Texinfo version 4.0 (NetBSD 1.5.1 included
+Texinfo version 3.12).
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{powerpc-*-eabiaix}powerpc-*-eabiaix
+Embedded PowerPC system in big endian mode with @option{-mcall-aix} selected as
+the default.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{powerpc-*-eabisim}powerpc-*-eabisim
+Embedded PowerPC system in big endian mode for use in running under the
+PSIM simulator.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{powerpc-*-eabi}powerpc-*-eabi
+Embedded PowerPC system in big endian mode.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{powerpcle-*-elf}powerpcle-*-elf, powerpcle-*-sysv4
+PowerPC system in little endian mode, running System V.4.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{powerpcle-*-eabisim}powerpcle-*-eabisim
+Embedded PowerPC system in little endian mode for use in running under
+the PSIM simulator.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{powerpcle-*-eabi}powerpcle-*-eabi
+Embedded PowerPC system in little endian mode.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{powerpcle-*-winnt}powerpcle-*-winnt, powerpcle-*-pe
+PowerPC system in little endian mode running Windows NT@.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{romp-*-aos}romp-*-aos, romp-*-mach
+The only operating systems supported for the IBM RT PC are AOS and
+MACH@.  GCC does not support AIX running on the RT@.  We recommend you
+compile GCC with an earlier version of itself; if you compile GCC
+with @command{hc}, the Metaware compiler, it will work, but you will get
+mismatches between the stage 2 and stage 3 compilers in various files.
+These errors are minor differences in some floating-point constants and
+can be safely ignored; the stage 3 compiler is correct.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{s390-*-linux*}s390-*-linux*
+S/390 system running Linux for S/390@. 
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{s390x-*-linux*}s390x-*-linux*
+zSeries system (64 Bit) running Linux for zSeries@. 
+
+@html
+</p>
+<hr>
+@end html
+@c Please use Solaris 2 to refer to all release of Solaris, starting
+@c with 2.0 until 2.6, 7, and 8.  Solaris 1 was a marketing name for
+@c SunOS 4 releases which we don't use to avoid confusion.  Solaris
+@c alone is too unspecific and must be avoided.
+@heading @anchor{*-*-solaris2*}*-*-solaris2*
+
+Sun does not ship a C compiler with Solaris 2.  To bootstrap and install
+GCC you first have to install a pre-built compiler, see our
+@uref{binaries.html,,binaries page} for details.
+
+The Solaris 2 @command{/bin/sh} will often fail to configure
+@file{libstdc++-v3}, @file{boehm-gc} or
+@file{libjava}.  If you encounter this problem, set @env{CONFIG_SHELL} to
+@command{/bin/ksh} in your environment and run @command{make bootstrap} again.
+Another possibility that sometimes helps is to remove
+@file{*-*-solaris2*/config.cache}.
+
+Solaris 2 comes with a number of optional OS packages.  Some of these
+packages are needed to use GCC fully, namely @code{SUNWarc},
+@code{SUNWbtool}, @code{SUNWesu}, @code{SUNWhea}, @code{SUNWlibm},
+@code{SUNWsprot}, and @code{SUNWtoo}.  If you did not install all
+optional packages when installing Solaris 2, you will need to verify that
+the packages that GCC needs are installed.
+
+To check whether an optional package is installed, use
+the @command{pkginfo} command.  To add an optional package, use the
+@command{pkgadd} command.  For further details, see the Solaris 2
+documentation.
+
+Trying to use the linker and other tools in
+@file{/usr/ucb} to install GCC has been observed to cause trouble.
+For example, the linker may hang indefinitely.  The fix is to remove
+@file{/usr/ucb} from your @env{PATH}.
+
+All releases of GNU binutils prior to 2.11.2 have known bugs on this
+platform.  We recommend the use of GNU binutils 2.11.2 or the vendor
+tools (Sun @command{as}, Sun @command{ld}).
+
+Sun bug 4296832 turns up when compiling X11 headers with GCC 2.95 or
+newer: @command{g++} will complain that types are missing.  These headers assume
+that omitting the type means @code{int}; this assumption worked for C89 but
+is wrong for C++, and is now wrong for C99 also.
+
+@command{g++} accepts such (invalid) constructs with the option
+@option{-fpermissive}; it
+will assume that any missing type is @code{int} (as defined by C89).
+
+There are patches for Solaris 2.6 (105633-56 or newer for SPARC,
+106248-42 or newer for Intel), Solaris 7 (108376-21 or newer for SPARC,
+108377-20 for Intel), and Solaris 8 (108652-24 or newer for SPARC,
+108653-22 for Intel) that fix this bug.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{sparc-sun-solaris2*}sparc-sun-solaris2*
+
+Sun @command{as} 4.x is broken in that it cannot cope with long symbol names.
+A typical error message might look similar to the following:
+
+@samp{/usr/ccs/bin/as: "/var/tmp/ccMsw135.s", line 11041:
+error: can't compute value of an expression involving an external symbol.}
+
+This is Sun bug 4237974.  This is fixed with patch 108908-02 for Solaris
+2.6 and has been fixed in later (5.x) versions of the assembler,
+starting with Solaris 7.
+
+Starting with Solaris 7, the operating system is capable of executing
+64-bit SPARC V9 binaries.  GCC 3.1 and later should properly support
+this.  GCC 3.0 lacks the infrastructure necessary to support this
+configuration properly.  However, if all you want is code tuned for
+the UltraSPARC CPU, you should try the @option{-mtune=ultrasparc}
+option instead, which should be safe from those bugs and produce code
+that, unlike full 64-bit code, can still run on non-UltraSPARC
+machines.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{sparc-sun-solaris2.7}sparc-sun-solaris2.7
+
+Sun patch 107058-01 (1999-01-13) for Solaris 7/SPARC triggers a bug in
+the dynamic linker.  This problem (Sun bug 4210064) affects GCC 2.8
+and later, including all EGCS releases.  Sun formerly recommended
+107058-01 for all Solaris 7 users, but around 1999-09-01 it started to
+recommend it only for people who use Sun's compilers.
+
+Here are some workarounds to this problem:
+@itemize @bullet
+@item
+Do not install Sun patch 107058-01 until after Sun releases a
+complete patch for bug 4210064.  This is the simplest course to take,
+unless you must also use Sun's C compiler.  Unfortunately 107058-01
+is preinstalled on some new Solaris 7-based hosts, so you may have to
+back it out.
+
+@item
+Copy the original, unpatched Solaris 7
+@command{/usr/ccs/bin/as} into
+@command{/usr/local/lib/gcc-lib/sparc-sun-solaris2.7/3.0/as},
+adjusting the latter name to fit your local conventions and software
+version numbers.
+
+@item
+Install Sun patch 106950-03 (1999-05-25) or later.  Nobody with
+both 107058-01 and 106950-03 installed has reported the bug with GCC
+and Sun's dynamic linker.  This last course of action is riskiest,
+for two reasons.  First, you must install 106950 on all hosts that
+run code generated by GCC; it doesn't suffice to install it only on
+the hosts that run GCC itself.  Second, Sun says that 106950-03 is
+only a partial fix for bug 4210064, but Sun doesn't know whether the
+partial fix is adequate for GCC@.  Revision -08 or later should fix
+the bug.  The current (as of 2001-09-24) revision is -14, and is included in
+the Solaris 7 Recommended Patch Cluster. 
+@end itemize
+
+
+@html
+<p>
+<hr>
+@end html
+@heading @anchor{*-*-solaris2.8}*-*-solaris2.8
+
+The Solaris 8 linker fails to link some @samp{libjava} programs if
+previously-installed GCC java libraries already exist in the configured
+prefix.  For this reason, @samp{libgcj} is disabled by default on Solaris 8.
+If you use GNU @command{ld}, or if you don't have a previously-installed @samp{libgcj} in
+the same prefix, use @option{--enable-libgcj} to build and install the
+Java libraries.
+
+@html
+<p>
+<hr>
+@end html
+@heading @anchor{sparc-sun-sunos4*}sparc-sun-sunos4*
+
+A bug in the SunOS 4 linker will cause it to crash when linking
+@option{-fPIC} compiled objects (and will therefore not allow you to build
+shared libraries).
+
+To fix this problem you can either use the most recent version of
+binutils or get the latest SunOS 4 linker patch (patch ID 100170-10)
+from Sun's patch site.
+
+Sometimes on a Sun 4 you may observe a crash in the program
+@command{genflags} or @command{genoutput} while building GCC.  This is said to
+be due to a bug in @command{sh}.  You can probably get around it by running
+@command{genflags} or @command{genoutput} manually and then retrying the
+@command{make}.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{sparc-unknown-linux-gnulibc1}sparc-unknown-linux-gnulibc1
+
+It has been reported that you might need
+@uref{ftp://ftp.yggdrasil.com/private/hjl,,binutils 2.8.1.0.23}
+for this platform, too.
+
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{sparc-*-linux*}sparc-*-linux*
+
+GCC versions 3.0 and higher require binutils 2.11.2 and glibc 2.2.4
+or newer on this platform.  All earlier binutils and glibc
+releases mishandled unaligned relocations on @code{sparc-*-*} targets.
+
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{sparc64-*-*}sparc64-*-*
+
+GCC version 2.95 is not able to compile code correctly for
+@code{sparc64} targets.  Users of the Linux kernel, at least,
+can use the @code{sparc32} program to start up a new shell
+invocation with an environment that causes @command{configure} to
+recognize (via @samp{uname -a}) the system as @samp{sparc-*-*} instead.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{sparcv9-*-solaris2*}sparcv9-*-solaris2*
+
+The following compiler flags must be specified in the configure
+step in order to bootstrap this target with the Sun compiler:
+
+@example
+   % CC="cc -xildoff -xarch=v9" @var{srcdir}/configure [@var{options}] [@var{target}]
+@end example
+
+@option{-xildoff} turns off the incremental linker, and @option{-xarch=v9}
+specifies the v9 architecture to the Sun linker and assembler.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{#*-*-sysv*}*-*-sysv*
+On System V release 3, you may get this error message
+while linking:
+
+@smallexample
+ld fatal: failed to write symbol name @var{something}
+ in strings table for file @var{whatever}
+@end smallexample
+
+This probably indicates that the disk is full or your ulimit won't allow
+the file to be as large as it needs to be.
+
+This problem can also result because the kernel parameter @code{MAXUMEM}
+is too small.  If so, you must regenerate the kernel and make the value
+much larger.  The default value is reported to be 1024; a value of 32768
+is said to work.  Smaller values may also work.
+
+On System V, if you get an error like this,
+
+@example
+/usr/local/lib/bison.simple: In function `yyparse':
+/usr/local/lib/bison.simple:625: virtual memory exhausted
+@end example
+
+@noindent
+that too indicates a problem with disk space, ulimit, or @code{MAXUMEM}.
+
+On a System V release 4 system, make sure @file{/usr/bin} precedes
+@file{/usr/ucb} in @code{PATH}.  The @code{cc} command in
+@file{/usr/ucb} uses libraries which have bugs.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{vax-dec-ultrix}vax-dec-ultrix
+Don't try compiling with VAX C (@code{vcc}).  It produces incorrect code
+in some cases (for example, when @code{alloca} is used).
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{we32k-*-*}we32k-*-*
+These computers are also known as the 3b2, 3b5, 3b20 and other similar
+names.  (However, the 3b1 is actually a 68000.)
+
+Don't use @option{-g} when compiling with the system's compiler.  The
+system's linker seems to be unable to handle such a large program with
+debugging information.
+
+The system's compiler runs out of capacity when compiling @file{stmt.c}
+in GCC@.  You can work around this by building @file{cpp} in GCC
+first, then use that instead of the system's preprocessor with the
+system's C compiler to compile @file{stmt.c}.  Here is how:
+
+@smallexample
+mv /lib/cpp /lib/cpp.att
+cp cpp /lib/cpp.gnu
+echo '/lib/cpp.gnu -traditional $@{1+"$@@"@}' > /lib/cpp
+chmod +x /lib/cpp
+@end smallexample
+
+The system's compiler produces bad code for some of the GCC
+optimization files.  So you must build the stage 2 compiler without
+optimization.  Then build a stage 3 compiler with optimization.
+That executable should work.  Here are the necessary commands:
+
+@smallexample
+make LANGUAGES=c CC=stage1/xgcc CFLAGS="-Bstage1/ -g"
+make stage2
+make CC=stage2/xgcc CFLAGS="-Bstage2/ -g -O"
+@end smallexample
+
+You may need to raise the ULIMIT setting to build a C++ compiler,
+as the file @file{cc1plus} is larger than one megabyte.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{xtensa-*-elf}xtensa-*-elf
+
+This target is intended for embedded Xtensa systems using the
+@samp{newlib} C library.  It uses ELF but does not support shared
+objects.  Designed-defined instructions specified via the
+Tensilica Instruction Extension (TIE) language are only supported
+through inline assembly.
+
+The Xtensa configuration information must be specified prior to
+building GCC@.  The @file{gcc/config/xtensa/xtensa-config.h} header
+file contains the configuration information.  If you created your
+own Xtensa configuration with the Xtensa Processor Generator, the
+downloaded files include a customized copy of this header file,
+which you can use to replace the default header file.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{xtensa-*-linux*}xtensa-*-linux*
+
+This target is for Xtensa systems running GNU/Linux.  It supports ELF
+shared objects and the GNU C library (glibc).  It also generates
+position-independent code (PIC) regardless of whether the
+@option{-fpic} or @option{-fPIC} options are used.  In other
+respects, this target is the same as the 
+@uref{#xtensa-*-elf,,@samp{xtensa-*-elf}} target.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{windows}Microsoft Windows (32 bit)
+
+A port of GCC 2.95.x is included with the
+@uref{http://www.cygwin.com/,,Cygwin environment}.
+
+Current (as of early 2001) snapshots of GCC will build under Cygwin
+without modification.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{os2}OS/2
+
+GCC does not currently support OS/2.  However, Andrew Zabolotny has been
+working on a generic OS/2 port with pgcc.  The current code can be found
+at @uref{http://www.goof.com/pcg/os2/,,http://www.goof.com/pcg/os2/}.
+
+An older copy of GCC 2.8.1 is included with the EMX tools available at
+@uref{ftp://ftp.leo.org/pub/comp/os/os2/leo/devtools/emx+gcc/,,
+ftp://ftp.leo.org/pub/comp/os/os2/leo/devtools/emx+gcc/}.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{older}Older systems
+
+GCC contains support files for many older (1980s and early
+1990s) Unix variants.  For the most part, support for these systems
+has not been deliberately removed, but it has not been maintained for
+several years and may suffer from bitrot.  Support from some systems
+has been removed from GCC 3: fx80, ns32-ns-genix, pyramid, tahoe,
+gmicro, spur; most of these targets had not been updated since GCC
+version 1.
+
+Support for older systems as targets for cross-compilation is less
+problematic than support for them as hosts for GCC; if an enthusiast
+wishes to make such a target work again (including resurrecting any
+of the targets that never worked with GCC 2, starting from the last
+CVS version before they were removed), patches
+@uref{../contribute.html,,following the usual requirements}
+would be likely to be accepted, since they should not affect the
+support for more modern targets.
+
+Support for old systems as hosts for GCC can cause problems if the
+workarounds for compiler, library and operating system bugs affect the
+cleanliness or maintainability of the rest of GCC@.  In some cases, to
+bring GCC up on such a system, if still possible with current GCC, may
+require first installing an old version of GCC which did work on that
+system, and using it to compile a more recent GCC, to avoid bugs in
+the vendor compiler.  Old releases of GCC 1 and GCC 2 are available in
+the @file{old-releases} directory on the
+@uref{../mirrors.html,,GCC mirror sites}.  Header bugs may generally
+be avoided using @command{fixincludes}, but bugs or deficiencies in
+libraries and the operating system may still cause problems.
+
+For some systems, old versions of GNU binutils may also be useful,
+and are available from @file{pub/binutils/old-releases} on
+@uref{http://sources.redhat.com/mirrors.html,,sources.redhat.com mirror sites}.
+
+Some of the information on specific systems above relates to
+such older systems, but much of the information
+about GCC on such systems (which may no longer be applicable to
+current GCC) is to be found in the GCC texinfo manual.
+
+@html
+</p>
+<hr>
+@end html
+@heading @anchor{elf_targets}all ELF targets (SVR4, Solaris 2, etc.)
+
+C++ support is significantly better on ELF targets if you use the
+@uref{./configure.html#with-gnu-ld,,GNU linker}; duplicate copies of
+inlines, vtables and template instantiations will be discarded
+automatically.
+
+
+@html
+</p>
+<hr>
+<p>
+@end html
+@ifhtml
+@uref{./index.html,,Return to the GCC Installation page}
+@end ifhtml
+@end ifset
+
+@c ***Old documentation******************************************************
+@ifset oldhtml
+@include install-old.texi
+@html
+</p>
+<hr>
+<p>
+@end html
+@ifhtml
+@uref{./index.html,,Return to the GCC Installation page}
+@end ifhtml
+@end ifset
+
+@c ***GFDL********************************************************************
+@ifset gfdlhtml
+@include fdl.texi
+@html
+</p>
+<hr>
+<p>
+@end html
+@ifhtml
+@uref{./index.html,,Return to the GCC Installation page}
+@end ifhtml
+@end ifset
+
+@c ***************************************************************************
+@c Part 6 The End of the Document
+@ifinfo
+@comment node-name,     next,          previous, up
+@node    Concept Index, , GNU Free Documentation License, Top
+@end ifinfo
+
+@ifinfo
+@unnumbered Concept Index
+
+@printindex cp
+
+@contents
+@end ifinfo
+@bye
diff --git a/contrib/gcc/doc/install.texi2html b/contrib/gcc/doc/install.texi2html
new file mode 100755
index 0000000..3917e2a
--- /dev/null
+++ b/contrib/gcc/doc/install.texi2html
@@ -0,0 +1,31 @@
+#!/bin/sh
+#
+# Convert the GCC install documentation from texinfo format to HTML.
+#
+# $SOURCEDIR and $DESTDIR, resp., refer to the directory containing
+# the texinfo source and the directory to put the HTML version in.
+#
+# (C) 2001 Free Software Foundation
+# Originally by Gerald Pfeifer <pfeifer@dbai.tuwien.ac.at>, June 2001.
+#
+# This script is Free Software, and it can be copied, distributed and
+# modified as defined in the GNU General Public License.  A copy of
+# its license can be downloaded from http://www.gnu.org/copyleft/gpl.html
+
+SOURCEDIR=${SOURCEDIR-.}
+DESTDIR=${DESTDIR-HTML}
+
+MAKEINFO=${MAKEINFO-makeinfo}
+
+if [ ! -d $DESTDIR ]; then
+    mkdir -p $DESTDIR
+fi
+
+for x in index.html specific.html download.html configure.html \
+         build.html test.html finalinstall.html binaries.html old.html \
+         gfdl.html
+do
+    define=`echo $x | sed -e 's/\.//g'`
+    echo "define = $define"
+    $MAKEINFO -I $SOURCEDIR -I $SOURCEDIR/include $SOURCEDIR/install.texi --html --no-split -D$define -o$DESTDIR/$x
+done
diff --git a/contrib/gcc/doc/interface.texi b/contrib/gcc/doc/interface.texi
new file mode 100644
index 0000000..846de56
--- /dev/null
+++ b/contrib/gcc/doc/interface.texi
@@ -0,0 +1,102 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+@c 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Interface
+@chapter Interfacing to GCC Output
+@cindex interfacing to GCC output
+@cindex run-time conventions
+@cindex function call conventions
+@cindex conventions, run-time
+
+GCC is normally configured to use the same function calling convention
+normally in use on the target system.  This is done with the
+machine-description macros described (@pxref{Target Macros}).
+
+@cindex unions, returning
+@cindex structures, returning
+@cindex returning structures and unions
+However, returning of structure and union values is done differently on
+some target machines.  As a result, functions compiled with PCC
+returning such types cannot be called from code compiled with GCC,
+and vice versa.  This does not cause trouble often because few Unix
+library routines return structures or unions.
+
+GCC code returns structures and unions that are 1, 2, 4 or 8 bytes
+long in the same registers used for @code{int} or @code{double} return
+values.  (GCC typically allocates variables of such types in
+registers also.)  Structures and unions of other sizes are returned by
+storing them into an address passed by the caller (usually in a
+register).  The machine-description macros @code{STRUCT_VALUE} and
+@code{STRUCT_INCOMING_VALUE} tell GCC where to pass this address.
+
+By contrast, PCC on most target machines returns structures and unions
+of any size by copying the data into an area of static storage, and then
+returning the address of that storage as if it were a pointer value.
+The caller must copy the data from that memory area to the place where
+the value is wanted.  This is slower than the method used by GCC, and
+fails to be reentrant.
+
+On some target machines, such as RISC machines and the 80386, the
+standard system convention is to pass to the subroutine the address of
+where to return the value.  On these machines, GCC has been
+configured to be compatible with the standard compiler, when this method
+is used.  It may not be compatible for structures of 1, 2, 4 or 8 bytes.
+
+@cindex argument passing
+@cindex passing arguments
+GCC uses the system's standard convention for passing arguments.  On
+some machines, the first few arguments are passed in registers; in
+others, all are passed on the stack.  It would be possible to use
+registers for argument passing on any machine, and this would probably
+result in a significant speedup.  But the result would be complete
+incompatibility with code that follows the standard convention.  So this
+change is practical only if you are switching to GCC as the sole C
+compiler for the system.  We may implement register argument passing on
+certain machines once we have a complete GNU system so that we can
+compile the libraries with GCC@.
+
+On some machines (particularly the Sparc), certain types of arguments
+are passed ``by invisible reference''.  This means that the value is
+stored in memory, and the address of the memory location is passed to
+the subroutine.
+
+@cindex @code{longjmp} and automatic variables
+If you use @code{longjmp}, beware of automatic variables.  ISO C says that
+automatic variables that are not declared @code{volatile} have undefined
+values after a @code{longjmp}.  And this is all GCC promises to do,
+because it is very difficult to restore register variables correctly, and
+one of GCC's features is that it can put variables in registers without
+your asking it to.
+
+If you want a variable to be unaltered by @code{longjmp}, and you don't
+want to write @code{volatile} because old C compilers don't accept it,
+just take the address of the variable.  If a variable's address is ever
+taken, even if just to compute it and ignore it, then the variable cannot
+go in a register:
+
+@example
+@{
+  int careful;
+  &careful;
+  @dots{}
+@}
+@end example
+
+@cindex arithmetic libraries
+@cindex math libraries
+@opindex msoft-float
+Code compiled with GCC may call certain library routines.  Most of
+them handle arithmetic for which there are no instructions.  This
+includes multiply and divide on some machines, and floating point
+operations on any machine for which floating point support is disabled
+with @option{-msoft-float}.  Some standard parts of the C library, such as
+@code{bcopy} or @code{memcpy}, are also called automatically.  The usual
+function call interface is used for calling the library routines.
+
+Some of these routines can be defined in mostly machine-independent C;
+they appear in @file{libgcc2.c}.  Others must be hand-written in
+assembly language for each processor.  Wherever they are defined, they
+are compiled into the support library, @file{libgcc.a}, which is
+automatically searched when you link programs with GCC@.
diff --git a/contrib/gcc/doc/invoke.texi b/contrib/gcc/doc/invoke.texi
new file mode 100644
index 0000000..51db49a
--- /dev/null
+++ b/contrib/gcc/doc/invoke.texi
@@ -0,0 +1,10463 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
+@c 2000, 2001, 2002 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@ignore
+@c man begin COPYRIGHT
+Copyright @copyright{} 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
+1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.1 or
+any later version published by the Free Software Foundation; with the
+Invariant Sections being ``GNU General Public License'' and ``Funding
+Free Software'', the Front-Cover texts being (a) (see below), and with
+the Back-Cover Texts being (b) (see below).  A copy of the license is
+included in the gfdl(7) man page.
+
+(a) The FSF's Front-Cover Text is:
+
+     A GNU Manual
+
+(b) The FSF's Back-Cover Text is:
+
+     You have freedom to copy and modify this GNU Manual, like GNU
+     software.  Copies published by the Free Software Foundation raise
+     funds for GNU development.
+@c man end
+@c Set file name and title for the man page.
+@setfilename gcc
+@settitle GNU project C and C++ compiler
+@c man begin SYNOPSIS
+gcc [@option{-c}|@option{-S}|@option{-E}] [@option{-std=}@var{standard}]
+    [@option{-g}] [@option{-pg}] [@option{-O}@var{level}]
+    [@option{-W}@var{warn}@dots{}] [@option{-pedantic}]
+    [@option{-I}@var{dir}@dots{}] [@option{-L}@var{dir}@dots{}]
+    [@option{-D}@var{macro}[=@var{defn}]@dots{}] [@option{-U}@var{macro}]
+    [@option{-f}@var{option}@dots{}] [@option{-m}@var{machine-option}@dots{}]
+    [@option{-o} @var{outfile}] @var{infile}@dots{}
+
+Only the most useful options are listed here; see below for the
+remainder.  @samp{g++} accepts mostly the same options as @samp{gcc}.
+@c man end
+@c man begin SEEALSO
+gpl(7), gfdl(7), fsf-funding(7),
+cpp(1), gcov(1), g77(1), as(1), ld(1), gdb(1), adb(1), dbx(1), sdb(1)
+and the Info entries for @file{gcc}, @file{cpp}, @file{g77}, @file{as},
+@file{ld}, @file{binutils} and @file{gdb}.
+@c man end
+@c man begin BUGS
+For instructions on reporting bugs, see
+@w{@uref{http://gcc.gnu.org/bugs.html}}.  Use of the @command{gccbug}
+script to report bugs is recommended.
+@c man end
+@c man begin AUTHOR
+See the Info entry for @command{gcc}, or
+@w{@uref{http://gcc.gnu.org/onlinedocs/gcc/Contributors.html}},
+for contributors to GCC@.
+@c man end
+@end ignore
+
+@node Invoking GCC
+@chapter GCC Command Options
+@cindex GCC command options
+@cindex command options
+@cindex options, GCC command
+
+@c man begin DESCRIPTION
+
+When you invoke GCC, it normally does preprocessing, compilation,
+assembly and linking.  The ``overall options'' allow you to stop this
+process at an intermediate stage.  For example, the @option{-c} option
+says not to run the linker.  Then the output consists of object files
+output by the assembler.
+
+Other options are passed on to one stage of processing.  Some options
+control the preprocessor and others the compiler itself.  Yet other
+options control the assembler and linker; most of these are not
+documented here, since you rarely need to use any of them.
+
+@cindex C compilation options
+Most of the command line options that you can use with GCC are useful
+for C programs; when an option is only useful with another language
+(usually C++), the explanation says so explicitly.  If the description
+for a particular option does not mention a source language, you can use
+that option with all supported languages.
+
+@cindex C++ compilation options
+@xref{Invoking G++,,Compiling C++ Programs}, for a summary of special
+options for compiling C++ programs.
+
+@cindex grouping options
+@cindex options, grouping
+The @command{gcc} program accepts options and file names as operands.  Many
+options have multi-letter names; therefore multiple single-letter options
+may @emph{not} be grouped: @option{-dr} is very different from @w{@samp{-d
+-r}}.
+
+@cindex order of options
+@cindex options, order
+You can mix options and other arguments.  For the most part, the order
+you use doesn't matter.  Order does matter when you use several options
+of the same kind; for example, if you specify @option{-L} more than once,
+the directories are searched in the order specified.
+
+Many options have long names starting with @samp{-f} or with
+@samp{-W}---for example, @option{-fforce-mem},
+@option{-fstrength-reduce}, @option{-Wformat} and so on.  Most of
+these have both positive and negative forms; the negative form of
+@option{-ffoo} would be @option{-fno-foo}.  This manual documents
+only one of these two forms, whichever one is not the default.
+
+@c man end
+
+@xref{Option Index}, for an index to GCC's options.
+
+@menu
+* Option Summary::	Brief list of all options, without explanations.
+* Overall Options::     Controlling the kind of output:
+                        an executable, object files, assembler files,
+                        or preprocessed source.
+* Invoking G++::	Compiling C++ programs.
+* C Dialect Options::   Controlling the variant of C language compiled.
+* C++ Dialect Options:: Variations on C++.
+* Objective-C Dialect Options:: Variations on Objective-C.
+* Language Independent Options:: Controlling how diagnostics should be
+                        formatted.
+* Warning Options::     How picky should the compiler be?
+* Debugging Options::   Symbol tables, measurements, and debugging dumps.
+* Optimize Options::    How much optimization?
+* Preprocessor Options:: Controlling header files and macro definitions.
+                         Also, getting dependency information for Make.
+* Assembler Options::   Passing options to the assembler.
+* Link Options::        Specifying libraries and so on.
+* Directory Options::   Where to find header files and libraries.
+                        Where to find the compiler executable files.
+* Spec Files::          How to pass switches to sub-processes.
+* Target Options::      Running a cross-compiler, or an old version of GCC.
+* Submodel Options::    Specifying minor hardware or convention variations,
+                        such as 68010 vs 68020.
+* Code Gen Options::    Specifying conventions for function calls, data layout
+                        and register usage.
+* Environment Variables:: Env vars that affect GCC.
+* Running Protoize::    Automatically adding or removing function prototypes.
+@end menu
+
+@c man begin OPTIONS
+
+@node Option Summary
+@section Option Summary
+
+Here is a summary of all the options, grouped by type.  Explanations are
+in the following sections.
+
+@table @emph
+@item Overall Options
+@xref{Overall Options,,Options Controlling the Kind of Output}.
+@gccoptlist{
+-c  -S  -E  -o @var{file}  -pipe  -pass-exit-codes  -x @var{language} @gol
+-v  --target-help  --help}
+
+@item C Language Options
+@xref{C Dialect Options,,Options Controlling C Dialect}.
+@gccoptlist{
+-ansi  -std=@var{standard}  -aux-info @var{filename} @gol
+-fno-asm  -fno-builtin -fno-builtin-@var{function} @gol
+-fhosted  -ffreestanding @gol
+-trigraphs  -traditional  -traditional-cpp @gol
+-fallow-single-precision  -fcond-mismatch @gol
+-fsigned-bitfields  -fsigned-char @gol
+-funsigned-bitfields  -funsigned-char @gol
+-fwritable-strings  -fshort-wchar}
+
+@item C++ Language Options
+@xref{C++ Dialect Options,,Options Controlling C++ Dialect}.
+@gccoptlist{
+-fno-access-control  -fcheck-new  -fconserve-space @gol
+-fno-const-strings  -fdollars-in-identifiers @gol
+-fno-elide-constructors @gol
+-fno-enforce-eh-specs  -fexternal-templates @gol
+-falt-external-templates @gol
+-ffor-scope  -fno-for-scope  -fno-gnu-keywords @gol
+-fno-implicit-templates @gol
+-fno-implicit-inline-templates @gol
+-fno-implement-inlines  -fms-extensions @gol
+-fno-nonansi-builtins  -fno-operator-names @gol
+-fno-optional-diags  -fpermissive @gol
+-frepo  -fno-rtti  -fstats  -ftemplate-depth-@var{n} @gol
+-fuse-cxa-atexit  -fvtable-gc  -fno-weak  -nostdinc++ @gol
+-fno-default-inline  -Wctor-dtor-privacy @gol
+-Wnon-virtual-dtor  -Wreorder @gol
+-Weffc++  -Wno-deprecated @gol
+-Wno-non-template-friend  -Wold-style-cast @gol
+-Woverloaded-virtual  -Wno-pmf-conversions @gol
+-Wsign-promo  -Wsynth}
+
+@item Objective-C Language Options
+@xref{Objective-C Dialect Options,,Options Controlling Objective-C Dialect}.
+@gccoptlist{
+-fconstant-string-class=@var{class-name} @gol
+-fgnu-runtime  -fnext-runtime  -gen-decls @gol
+-Wno-protocol  -Wselector}
+
+@item Language Independent Options
+@xref{Language Independent Options,,Options to Control Diagnostic Messages Formatting}.
+@gccoptlist{
+-fmessage-length=@var{n}  @gol
+-fdiagnostics-show-location=@r{[}once@r{|}every-line@r{]}}
+
+@item Warning Options
+@xref{Warning Options,,Options to Request or Suppress Warnings}.
+@gccoptlist{
+-fsyntax-only  -pedantic  -pedantic-errors @gol
+-w  -W  -Wall  -Waggregate-return @gol
+-Wcast-align  -Wcast-qual  -Wchar-subscripts  -Wcomment @gol
+-Wconversion  -Wno-deprecated-declarations @gol
+-Wdisabled-optimization  -Wdiv-by-zero  -Werror @gol
+-Wfloat-equal  -Wformat  -Wformat=2 @gol
+-Wformat-nonliteral  -Wformat-security @gol
+-Wimplicit  -Wimplicit-int  @gol
+-Wimplicit-function-declaration @gol
+-Werror-implicit-function-declaration @gol
+-Wimport  -Winline @gol
+-Wlarger-than-@var{len}  -Wlong-long @gol
+-Wmain  -Wmissing-braces  -Wmissing-declarations @gol
+-Wmissing-format-attribute  -Wmissing-noreturn @gol
+-Wmultichar  -Wno-format-extra-args  -Wno-format-y2k @gol
+-Wno-import  -Wpacked  -Wpadded @gol
+-Wparentheses  -Wpointer-arith  -Wredundant-decls @gol
+-Wreturn-type  -Wsequence-point  -Wshadow @gol
+-Wsign-compare  -Wswitch  -Wsystem-headers @gol
+-Wtrigraphs  -Wundef  -Wuninitialized @gol
+-Wunknown-pragmas  -Wunreachable-code @gol
+-Wunused  -Wunused-function  -Wunused-label  -Wunused-parameter @gol
+-Wunused-value  -Wunused-variable  -Wwrite-strings}
+
+@item C-only Warning Options
+@gccoptlist{
+-Wbad-function-cast  -Wmissing-prototypes  -Wnested-externs @gol
+-Wstrict-prototypes  -Wtraditional}
+
+@item Debugging Options
+@xref{Debugging Options,,Options for Debugging Your Program or GCC}.
+@gccoptlist{
+-d@var{letters}  -dumpspecs  -dumpmachine  -dumpversion @gol
+-fdump-unnumbered -fdump-translation-unit@r{[}-@var{n}@r{]} @gol
+-fdump-class-hierarchy@r{[}-@var{n}@r{]} @gol
+-fdump-tree-original@r{[}-@var{n}@r{]} -fdump-tree-optimized@r{[}-@var{n}@r{]} @gol
+-fdump-tree-inlined@r{[}-@var{n}@r{]} @gol
+-fmem-report  -fpretend-float @gol
+-fprofile-arcs  -ftest-coverage  -ftime-report @gol
+-g  -g@var{level}  -gcoff  -gdwarf  -gdwarf-1  -gdwarf-1+  -gdwarf-2 @gol
+-ggdb  -gstabs  -gstabs+  -gvms  -gxcoff  -gxcoff+ @gol
+-p  -pg  -print-file-name=@var{library}  -print-libgcc-file-name @gol
+-print-multi-directory  -print-multi-lib @gol
+-print-prog-name=@var{program}  -print-search-dirs  -Q @gol
+-save-temps  -time}
+
+@item Optimization Options
+@xref{Optimize Options,,Options that Control Optimization}.
+@gccoptlist{
+-falign-functions=@var{n}  -falign-jumps=@var{n} @gol
+-falign-labels=@var{n}  -falign-loops=@var{n}  @gol
+-fbranch-probabilities  -fcaller-saves -fcprop-registers @gol
+-fcse-follow-jumps  -fcse-skip-blocks  -fdata-sections @gol
+-fdelayed-branch  -fdelete-null-pointer-checks @gol
+-fexpensive-optimizations  -ffast-math  -ffloat-store @gol
+-fforce-addr  -fforce-mem  -ffunction-sections @gol
+-fgcse  -fgcse-lm  -fgcse-sm @gol
+-finline-functions  -finline-limit=@var{n}  -fkeep-inline-functions @gol
+-fkeep-static-consts  -fmerge-constants  -fmerge-all-constants @gol
+-fmove-all-movables  -fno-default-inline  -fno-defer-pop @gol
+-fno-function-cse  -fno-guess-branch-probability @gol
+-fno-inline  -fno-math-errno  -fno-peephole  -fno-peephole2 @gol
+-funsafe-math-optimizations -fno-trapping-math @gol
+-fomit-frame-pointer  -foptimize-register-move @gol
+-foptimize-sibling-calls  -fprefetch-loop-arrays @gol
+-freduce-all-givs -fregmove  -frename-registers @gol
+-frerun-cse-after-loop  -frerun-loop-opt @gol
+-fschedule-insns  -fschedule-insns2 @gol
+-fsingle-precision-constant  -fssa -fssa-ccp -fssa-dce @gol
+-fstrength-reduce  -fstrict-aliasing  -fthread-jumps  -ftrapv @gol
+-funroll-all-loops  -funroll-loops  @gol
+--param @var{name}=@var{value}
+-O  -O0  -O1  -O2  -O3  -Os}
+
+@item Preprocessor Options
+@xref{Preprocessor Options,,Options Controlling the Preprocessor}.
+@gccoptlist{
+-$  -A@var{question}=@var{answer}  -A-@var{question}@r{[}=@var{answer}@r{]} @gol
+-C  -dD  -dI  -dM  -dN @gol
+-D@var{macro}@r{[}=@var{defn}@r{]}  -E  -H @gol
+-idirafter @var{dir} @gol
+-include @var{file}  -imacros @var{file} @gol
+-iprefix @var{file}  -iwithprefix @var{dir} @gol
+-iwithprefixbefore @var{dir}  -isystem @var{dir} @gol
+-M  -MM  -MF  -MG  -MP  -MQ  -MT  -nostdinc  -P  -remap @gol
+-trigraphs  -undef  -U@var{macro}  -Wp,@var{option}}
+
+@item Assembler Option
+@xref{Assembler Options,,Passing Options to the Assembler}.
+@gccoptlist{
+-Wa,@var{option}}
+
+@item Linker Options
+@xref{Link Options,,Options for Linking}.
+@gccoptlist{
+@var{object-file-name}  -l@var{library} @gol
+-nostartfiles  -nodefaultlibs  -nostdlib @gol
+-s  -static  -static-libgcc  -shared  -shared-libgcc  -symbolic @gol
+-Wl,@var{option}  -Xlinker @var{option} @gol
+-u @var{symbol}}
+
+@item Directory Options
+@xref{Directory Options,,Options for Directory Search}.
+@gccoptlist{
+-B@var{prefix}  -I@var{dir}  -I-  -L@var{dir}  -specs=@var{file}}
+
+@item Target Options
+@c I wrote this xref this way to avoid overfull hbox. -- rms
+@xref{Target Options}.
+@gccoptlist{
+-b @var{machine}  -V @var{version}}
+
+@item Machine Dependent Options
+@xref{Submodel Options,,Hardware Models and Configurations}.
+
+@emph{M680x0 Options}
+@gccoptlist{
+-m68000  -m68020  -m68020-40  -m68020-60  -m68030  -m68040 @gol
+-m68060  -mcpu32  -m5200  -m68881  -mbitfield  -mc68000  -mc68020   @gol
+-mfpa  -mnobitfield  -mrtd  -mshort  -msoft-float  -mpcrel @gol
+-malign-int  -mstrict-align}
+
+@emph{M68hc1x Options}
+@gccoptlist{
+-m6811  -m6812  -m68hc11  -m68hc12 @gol
+-mauto-incdec  -mshort  -msoft-reg-count=@var{count}}
+
+@emph{VAX Options}
+@gccoptlist{
+-mg  -mgnu  -munix}
+
+@emph{SPARC Options}
+@gccoptlist{
+-mcpu=@var{cpu-type} @gol
+-mtune=@var{cpu-type} @gol
+-mcmodel=@var{code-model} @gol
+-m32  -m64 @gol
+-mapp-regs  -mbroken-saverestore  -mcypress @gol
+-mepilogue  -mfaster-structs  -mflat @gol
+-mfpu  -mhard-float  -mhard-quad-float @gol
+-mimpure-text  -mlive-g0  -mno-app-regs @gol
+-mno-epilogue  -mno-faster-structs  -mno-flat  -mno-fpu @gol
+-mno-impure-text  -mno-stack-bias  -mno-unaligned-doubles @gol
+-msoft-float  -msoft-quad-float  -msparclite  -mstack-bias @gol
+-msupersparc  -munaligned-doubles  -mv8}
+
+@emph{Convex Options}
+@gccoptlist{
+-mc1  -mc2  -mc32  -mc34  -mc38 @gol
+-margcount  -mnoargcount @gol
+-mlong32  -mlong64 @gol
+-mvolatile-cache  -mvolatile-nocache}
+
+@emph{AMD29K Options}
+@gccoptlist{
+-m29000  -m29050  -mbw  -mnbw  -mdw  -mndw @gol
+-mlarge  -mnormal  -msmall @gol
+-mkernel-registers  -mno-reuse-arg-regs @gol
+-mno-stack-check  -mno-storem-bug @gol
+-mreuse-arg-regs  -msoft-float  -mstack-check @gol
+-mstorem-bug  -muser-registers}
+
+@emph{ARM Options}
+@gccoptlist{
+-mapcs-frame  -mno-apcs-frame @gol
+-mapcs-26  -mapcs-32 @gol
+-mapcs-stack-check  -mno-apcs-stack-check @gol
+-mapcs-float  -mno-apcs-float @gol
+-mapcs-reentrant  -mno-apcs-reentrant @gol
+-msched-prolog  -mno-sched-prolog @gol
+-mlittle-endian  -mbig-endian  -mwords-little-endian @gol
+-malignment-traps  -mno-alignment-traps @gol
+-msoft-float  -mhard-float  -mfpe @gol
+-mthumb-interwork  -mno-thumb-interwork @gol
+-mcpu=@var{name}  -march=@var{name}  -mfpe=@var{name}  @gol
+-mstructure-size-boundary=@var{n} @gol
+-mbsd -mxopen  -mno-symrename @gol
+-mabort-on-noreturn @gol
+-mlong-calls  -mno-long-calls @gol
+-msingle-pic-base  -mno-single-pic-base @gol
+-mpic-register=@var{reg} @gol
+-mnop-fun-dllimport @gol
+-mpoke-function-name @gol
+-mthumb  -marm @gol
+-mtpcs-frame  -mtpcs-leaf-frame @gol
+-mcaller-super-interworking  -mcallee-super-interworking }
+
+@emph{MN10200 Options}
+@gccoptlist{
+-mrelax}
+
+@emph{MN10300 Options}
+@gccoptlist{
+-mmult-bug  -mno-mult-bug @gol
+-mam33  -mno-am33 @gol
+-mno-crt0  -mrelax}
+
+@emph{M32R/D Options}
+@gccoptlist{
+-m32rx -m32r -mcode-model=@var{model-type}  -msdata=@var{sdata-type} @gol
+-G @var{num}}
+
+@emph{M88K Options}
+@gccoptlist{
+-m88000  -m88100  -m88110  -mbig-pic @gol
+-mcheck-zero-division  -mhandle-large-shift @gol
+-midentify-revision  -mno-check-zero-division @gol
+-mno-ocs-debug-info  -mno-ocs-frame-position @gol
+-mno-optimize-arg-area  -mno-serialize-volatile @gol
+-mno-underscores  -mocs-debug-info @gol
+-mocs-frame-position  -moptimize-arg-area @gol
+-mserialize-volatile  -mshort-data-@var{num}  -msvr3 @gol
+-msvr4  -mtrap-large-shift  -muse-div-instruction @gol
+-mversion-03.00  -mwarn-passed-structs}
+
+@emph{RS/6000 and PowerPC Options}
+@gccoptlist{
+-mcpu=@var{cpu-type} @gol
+-mtune=@var{cpu-type} @gol
+-mpower  -mno-power  -mpower2  -mno-power2 @gol
+-mpowerpc  -mpowerpc64  -mno-powerpc @gol
+-maltivec -mno-altivec @gol
+-mpowerpc-gpopt  -mno-powerpc-gpopt @gol
+-mpowerpc-gfxopt  -mno-powerpc-gfxopt @gol
+-mnew-mnemonics  -mold-mnemonics @gol
+-mfull-toc   -mminimal-toc  -mno-fop-in-toc  -mno-sum-in-toc @gol
+-m64  -m32  -mxl-call  -mno-xl-call  -mpe @gol
+-msoft-float  -mhard-float  -mmultiple  -mno-multiple @gol
+-mstring  -mno-string  -mupdate  -mno-update @gol
+-mfused-madd  -mno-fused-madd  -mbit-align  -mno-bit-align @gol
+-mstrict-align  -mno-strict-align  -mrelocatable @gol
+-mno-relocatable  -mrelocatable-lib  -mno-relocatable-lib @gol
+-mtoc  -mno-toc -mlittle  -mlittle-endian  -mbig  -mbig-endian @gol
+-mcall-aix -mcall-sysv -mcall-netbsd @gol
+-maix-struct-return -msvr4-struct-return
+-mabi=altivec @gol
+-mprototype  -mno-prototype @gol
+-msim  -mmvme  -mads  -myellowknife  -memb -msdata @gol
+-msdata=@var{opt}  -mvxworks -G @var{num} -pthread}
+
+@emph{RT Options}
+@gccoptlist{
+-mcall-lib-mul  -mfp-arg-in-fpregs  -mfp-arg-in-gregs @gol
+-mfull-fp-blocks  -mhc-struct-return  -min-line-mul @gol
+-mminimum-fp-blocks  -mnohc-struct-return}
+
+@emph{MIPS Options}
+@gccoptlist{
+-mabicalls -march=@var{cpu-type} -mtune=@var{cpu=type} @gol
+-mcpu=@var{cpu-type} -membedded-data  -muninit-const-in-rodata @gol
+-membedded-pic  -mfp32  -mfp64  -mfused-madd  -mno-fused-madd @gol
+-mgas  -mgp32  -mgp64 @gol
+-mgpopt  -mhalf-pic  -mhard-float  -mint64  -mips1 @gol
+-mips2  -mips3  -mips4  -mlong64  -mlong32  -mlong-calls  -mmemcpy @gol
+-mmips-as  -mmips-tfile  -mno-abicalls @gol
+-mno-embedded-data  -mno-uninit-const-in-rodata @gol
+-mno-embedded-pic  -mno-gpopt  -mno-long-calls @gol
+-mno-memcpy  -mno-mips-tfile  -mno-rnames  -mno-stats @gol
+-mrnames  -msoft-float @gol
+-m4650  -msingle-float  -mmad @gol
+-mstats  -EL  -EB  -G @var{num}  -nocpp @gol
+-mabi=32  -mabi=n32  -mabi=64  -mabi=eabi @gol
+-mfix7000  -mno-crt0 -mflush-func=@var{func} -mno-flush-func}
+
+@emph{i386 and x86-64 Options}
+@gccoptlist{
+-mcpu=@var{cpu-type}  -march=@var{cpu-type} -mfpmath=@var{unit} @gol
+-masm=@var{dialect}  -mno-fancy-math-387 @gol
+-mno-fp-ret-in-387  -msoft-float  -msvr3-shlib @gol
+-mno-wide-multiply  -mrtd  -malign-double @gol
+-mpreferred-stack-boundary=@var{num} @gol
+-mmmx  -msse -msse2 -msse-math -m3dnow @gol
+-mthreads  -mno-align-stringops  -minline-all-stringops @gol
+-mpush-args  -maccumulate-outgoing-args  -m128bit-long-double @gol
+-m96bit-long-double  -mregparm=@var{num}  -momit-leaf-frame-pointer @gol
+-mno-red-zone@gol
+-m32 -m64}
+
+@emph{HPPA Options}
+@gccoptlist{
+-march=@var{architecture-type} @gol
+-mbig-switch  -mdisable-fpregs  -mdisable-indexing @gol
+-mfast-indirect-calls  -mgas  -mjump-in-delay @gol
+-mlong-load-store  -mno-big-switch  -mno-disable-fpregs @gol
+-mno-disable-indexing  -mno-fast-indirect-calls  -mno-gas @gol
+-mno-jump-in-delay  -mno-long-load-store @gol
+-mno-portable-runtime  -mno-soft-float @gol
+-mno-space-regs  -msoft-float  -mpa-risc-1-0 @gol
+-mpa-risc-1-1  -mpa-risc-2-0  -mportable-runtime @gol
+-mschedule=@var{cpu-type}  -mspace-regs}
+
+@emph{Intel 960 Options}
+@gccoptlist{
+-m@var{cpu-type}  -masm-compat  -mclean-linkage @gol
+-mcode-align  -mcomplex-addr  -mleaf-procedures @gol
+-mic-compat  -mic2.0-compat  -mic3.0-compat @gol
+-mintel-asm  -mno-clean-linkage  -mno-code-align @gol
+-mno-complex-addr  -mno-leaf-procedures @gol
+-mno-old-align  -mno-strict-align  -mno-tail-call @gol
+-mnumerics  -mold-align  -msoft-float  -mstrict-align @gol
+-mtail-call}
+
+@emph{DEC Alpha Options}
+@gccoptlist{
+-mno-fp-regs  -msoft-float  -malpha-as  -mgas @gol
+-mieee  -mieee-with-inexact  -mieee-conformant @gol
+-mfp-trap-mode=@var{mode}  -mfp-rounding-mode=@var{mode} @gol
+-mtrap-precision=@var{mode}  -mbuild-constants @gol
+-mcpu=@var{cpu-type}  -mtune=@var{cpu-type} @gol
+-mbwx  -mmax  -mfix  -mcix @gol
+-mfloat-vax  -mfloat-ieee @gol
+-mexplicit-relocs  -msmall-data  -mlarge-data @gol
+-mmemory-latency=@var{time}}
+
+@emph{DEC Alpha/VMS Options}
+@gccoptlist{
+-mvms-return-codes}
+
+@emph{Clipper Options}
+@gccoptlist{
+-mc300  -mc400}
+
+@emph{H8/300 Options}
+@gccoptlist{
+-mrelax  -mh  -ms  -mint32  -malign-300}
+
+@emph{SH Options}
+@gccoptlist{
+-m1  -m2  -m3  -m3e @gol
+-m4-nofpu  -m4-single-only  -m4-single  -m4 @gol
+-mb  -ml  -mdalign  -mrelax @gol
+-mbigtable  -mfmovd  -mhitachi  -mnomacsave @gol
+-mieee  -misize  -mpadstruct  -mspace @gol
+-mprefergot  -musermode}
+
+@emph{System V Options}
+@gccoptlist{
+-Qy  -Qn  -YP,@var{paths}  -Ym,@var{dir}}
+
+@emph{ARC Options}
+@gccoptlist{
+-EB  -EL @gol
+-mmangle-cpu  -mcpu=@var{cpu}  -mtext=@var{text-section} @gol
+-mdata=@var{data-section}  -mrodata=@var{readonly-data-section}}
+
+@emph{TMS320C3x/C4x Options}
+@gccoptlist{
+-mcpu=@var{cpu}  -mbig  -msmall  -mregparm  -mmemparm @gol
+-mfast-fix  -mmpyi  -mbk  -mti  -mdp-isr-reload @gol
+-mrpts=@var{count}  -mrptb  -mdb  -mloop-unsigned @gol
+-mparallel-insns  -mparallel-mpy  -mpreserve-float}
+
+@emph{V850 Options}
+@gccoptlist{
+-mlong-calls  -mno-long-calls  -mep  -mno-ep @gol
+-mprolog-function  -mno-prolog-function  -mspace @gol
+-mtda=@var{n}  -msda=@var{n}  -mzda=@var{n} @gol
+-mv850  -mbig-switch}
+
+@emph{NS32K Options}
+@gccoptlist{
+-m32032  -m32332  -m32532  -m32081  -m32381 @gol
+-mmult-add  -mnomult-add  -msoft-float  -mrtd  -mnortd @gol
+-mregparam  -mnoregparam  -msb  -mnosb @gol
+-mbitfield  -mnobitfield  -mhimem  -mnohimem}
+
+@emph{AVR Options}
+@gccoptlist{
+-mmcu=@var{mcu}  -msize  -minit-stack=@var{n}  -mno-interrupts @gol
+-mcall-prologues  -mno-tablejump  -mtiny-stack}
+
+@emph{MCore Options}
+@gccoptlist{
+-mhardlit  -mno-hardlit  -mdiv  -mno-div  -mrelax-immediates @gol
+-mno-relax-immediates  -mwide-bitfields  -mno-wide-bitfields @gol
+-m4byte-functions  -mno-4byte-functions  -mcallgraph-data @gol
+-mno-callgraph-data  -mslow-bytes  -mno-slow-bytes  -mno-lsim @gol
+-mlittle-endian  -mbig-endian  -m210  -m340  -mstack-increment}
+
+@emph{MMIX Options}
+@gccoptlist{
+-mlibfuncs -mno-libfuncs -mepsilon -mno-epsilon -mabi=gnu @gol
+-mabi=mmixware -mzero-extend -mknuthdiv -mtoplevel-symbols @gol
+-melf -mbranch-predict -mno-branch-predict}
+
+@emph{IA-64 Options}
+@gccoptlist{
+-mbig-endian  -mlittle-endian  -mgnu-as  -mgnu-ld  -mno-pic @gol
+-mvolatile-asm-stop  -mb-step  -mregister-names  -mno-sdata @gol
+-mconstant-gp  -mauto-pic  -minline-divide-min-latency @gol
+-minline-divide-max-throughput  -mno-dwarf2-asm @gol
+-mfixed-range=@var{register-range}}
+
+@emph{D30V Options}
+@gccoptlist{
+-mextmem  -mextmemory  -monchip  -mno-asm-optimize  -masm-optimize @gol
+-mbranch-cost=@var{n} -mcond-exec=@var{n}}
+
+@emph{S/390 and zSeries Options}
+@gccoptlist{
+-mhard-float  -msoft-float  -mbackchain  -mno-backchain @gol
+-msmall-exec  -mno-small-exec  -mmvcle -mno-mvcle @gol
+-m64 -m31 -mdebug -mno-debug}
+
+@emph{CRIS Options}
+@gccoptlist{
+-mcpu=@var{cpu} -march=@var{cpu} -mtune=@var{cpu} @gol
+-mmax-stack-frame=@var{n} -melinux-stacksize=@var{n} @gol
+-metrax4 -metrax100 -mpdebug -mcc-init -mno-side-effects @gol
+-mstack-align -mdata-align -mconst-align @gol
+-m32-bit -m16-bit -m8-bit -mno-prologue-epilogue -mno-gotplt @gol
+-melf -maout -melinux -mlinux -sim -sim2}
+
+@emph{PDP-11 Options}
+@gccoptlist{
+-mfpu  -msoft-float  -mac0  -mno-ac0  -m40  -m45  -m10 @gol
+-mbcopy  -mbcopy-builtin  -mint32  -mno-int16 @gol
+-mint16  -mno-int32  -mfloat32  -mno-float64 @gol
+-mfloat64  -mno-float32  -mabshi  -mno-abshi @gol
+-mbranch-expensive  -mbranch-cheap @gol
+-msplit  -mno-split  -munix-asm  -mdec-asm}
+
+@emph{Xstormy16 Options}
+@gccoptlist{
+-msim}
+
+@emph{Xtensa Options}
+@gccoptlist{
+-mbig-endian -mlittle-endian @gol
+-mdensity -mno-density @gol
+-mmac16 -mno-mac16 @gol
+-mmul16 -mno-mul16 @gol
+-mmul32 -mno-mul32 @gol
+-mnsa -mno-nsa @gol
+-mminmax -mno-minmax @gol
+-msext -mno-sext @gol
+-mbooleans -mno-booleans @gol
+-mhard-float -msoft-float @gol
+-mfused-madd -mno-fused-madd @gol
+-mserialize-volatile -mno-serialize-volatile @gol
+-mtext-section-literals -mno-text-section-literals @gol
+-mtarget-align -mno-target-align @gol
+-mlongcalls -mno-longcalls}
+
+@item Code Generation Options
+@xref{Code Gen Options,,Options for Code Generation Conventions}.
+@gccoptlist{
+-fcall-saved-@var{reg}  -fcall-used-@var{reg} @gol
+-ffixed-@var{reg} -fexceptions @gol
+-fnon-call-exceptions  -funwind-tables @gol
+-fasynchronous-unwind-tables @gol
+-finhibit-size-directive  -finstrument-functions @gol
+-fno-common  -fno-ident  -fno-gnu-linker @gol
+-fpcc-struct-return  -fpic  -fPIC @gol
+-freg-struct-return  -fshared-data  -fshort-enums @gol
+-fshort-double  -fvolatile @gol
+-fvolatile-global  -fvolatile-static @gol
+-fverbose-asm  -fpack-struct  -fstack-check @gol
+-fstack-limit-register=@var{reg}  -fstack-limit-symbol=@var{sym} @gol
+-fargument-alias  -fargument-noalias @gol
+-fargument-noalias-global  -fleading-underscore}
+@end table
+
+@menu
+* Overall Options::     Controlling the kind of output:
+                        an executable, object files, assembler files,
+                        or preprocessed source.
+* C Dialect Options::   Controlling the variant of C language compiled.
+* C++ Dialect Options:: Variations on C++.
+* Objective-C Dialect Options:: Variations on Objective-C.
+* Language Independent Options:: Controlling how diagnostics should be
+                        formatted.
+* Warning Options::     How picky should the compiler be?
+* Debugging Options::   Symbol tables, measurements, and debugging dumps.
+* Optimize Options::    How much optimization?
+* Preprocessor Options:: Controlling header files and macro definitions.
+                         Also, getting dependency information for Make.
+* Assembler Options::   Passing options to the assembler.
+* Link Options::        Specifying libraries and so on.
+* Directory Options::   Where to find header files and libraries.
+                        Where to find the compiler executable files.
+* Spec Files::          How to pass switches to sub-processes.
+* Target Options::      Running a cross-compiler, or an old version of GCC.
+@end menu
+
+@node Overall Options
+@section Options Controlling the Kind of Output
+
+Compilation can involve up to four stages: preprocessing, compilation
+proper, assembly and linking, always in that order.  The first three
+stages apply to an individual source file, and end by producing an
+object file; linking combines all the object files (those newly
+compiled, and those specified as input) into an executable file.
+
+@cindex file name suffix
+For any given input file, the file name suffix determines what kind of
+compilation is done:
+
+@table @gcctabopt
+@item @var{file}.c
+C source code which must be preprocessed.
+
+@item @var{file}.i
+C source code which should not be preprocessed.
+
+@item @var{file}.ii
+C++ source code which should not be preprocessed.
+
+@item @var{file}.m
+Objective-C source code.  Note that you must link with the library
+@file{libobjc.a} to make an Objective-C program work.
+
+@item @var{file}.mi
+Objective-C source code which should not be preprocessed.
+
+@item @var{file}.h
+C header file (not to be compiled or linked).
+
+@item @var{file}.cc
+@itemx @var{file}.cp
+@itemx @var{file}.cxx
+@itemx @var{file}.cpp
+@itemx @var{file}.c++
+@itemx @var{file}.C
+C++ source code which must be preprocessed.  Note that in @samp{.cxx},
+the last two letters must both be literally @samp{x}.  Likewise,
+@samp{.C} refers to a literal capital C@.
+
+@item @var{file}.f
+@itemx @var{file}.for
+@itemx @var{file}.FOR
+Fortran source code which should not be preprocessed.
+
+@item @var{file}.F
+@itemx @var{file}.fpp
+@itemx @var{file}.FPP
+Fortran source code which must be preprocessed (with the traditional
+preprocessor).
+
+@item @var{file}.r
+Fortran source code which must be preprocessed with a RATFOR
+preprocessor (not included with GCC)@.
+
+@xref{Overall Options,,Options Controlling the Kind of Output, g77,
+Using and Porting GNU Fortran}, for more details of the handling of
+Fortran input files.
+
+@c FIXME: Descriptions of Java file types.
+@c @var{file}.java
+@c @var{file}.class
+@c @var{file}.zip
+@c @var{file}.jar
+
+@item @var{file}.ads
+Ada source code file which contains a library unit declaration (a
+declaration of a package, subprogram, or generic, or a generic
+instantiation), or a library unit renaming declaration (a package,
+generic, or subprogram renaming declaration).  Such files are also
+called @dfn{specs}.
+
+@itemx @var{file}.adb
+Ada source code file containing a library unit body (a subprogram or
+package body).  Such files are also called @dfn{bodies}.
+
+@c GCC also knows about some suffixes for languages not yet included:
+@c Pascal:
+@c @var{file}.p
+@c @var{file}.pas
+
+@item @var{file}.ch
+@itemx @var{file}.chi
+CHILL source code (preprocessed with the traditional preprocessor).
+
+@item @var{file}.s
+Assembler code.
+
+@item @var{file}.S
+Assembler code which must be preprocessed.
+
+@item @var{other}
+An object file to be fed straight into linking.
+Any file name with no recognized suffix is treated this way.
+@end table
+
+@opindex x
+You can specify the input language explicitly with the @option{-x} option:
+
+@table @gcctabopt
+@item -x @var{language}
+Specify explicitly the @var{language} for the following input files
+(rather than letting the compiler choose a default based on the file
+name suffix).  This option applies to all following input files until
+the next @option{-x} option.  Possible values for @var{language} are:
+@example
+c  c-header  cpp-output
+c++  c++-cpp-output
+objective-c  objc-cpp-output
+assembler  assembler-with-cpp
+ada
+chill
+f77  f77-cpp-input  ratfor
+java
+@end example
+
+@item -x none
+Turn off any specification of a language, so that subsequent files are
+handled according to their file name suffixes (as they are if @option{-x}
+has not been used at all).
+
+@item -pass-exit-codes
+@opindex pass-exit-codes
+Normally the @command{gcc} program will exit with the code of 1 if any
+phase of the compiler returns a non-success return code.  If you specify
+@option{-pass-exit-codes}, the @command{gcc} program will instead return with
+numerically highest error produced by any phase that returned an error
+indication.
+@end table
+
+If you only want some of the stages of compilation, you can use
+@option{-x} (or filename suffixes) to tell @command{gcc} where to start, and
+one of the options @option{-c}, @option{-S}, or @option{-E} to say where
+@command{gcc} is to stop.  Note that some combinations (for example,
+@samp{-x cpp-output -E}) instruct @command{gcc} to do nothing at all.
+
+@table @gcctabopt
+@item -c
+@opindex c
+Compile or assemble the source files, but do not link.  The linking
+stage simply is not done.  The ultimate output is in the form of an
+object file for each source file.
+
+By default, the object file name for a source file is made by replacing
+the suffix @samp{.c}, @samp{.i}, @samp{.s}, etc., with @samp{.o}.
+
+Unrecognized input files, not requiring compilation or assembly, are
+ignored.
+
+@item -S
+@opindex S
+Stop after the stage of compilation proper; do not assemble.  The output
+is in the form of an assembler code file for each non-assembler input
+file specified.
+
+By default, the assembler file name for a source file is made by
+replacing the suffix @samp{.c}, @samp{.i}, etc., with @samp{.s}.
+
+Input files that don't require compilation are ignored.
+
+@item -E
+@opindex E
+Stop after the preprocessing stage; do not run the compiler proper.  The
+output is in the form of preprocessed source code, which is sent to the
+standard output.
+
+Input files which don't require preprocessing are ignored.
+
+@cindex output file option
+@item -o @var{file}
+@opindex o
+Place output in file @var{file}.  This applies regardless to whatever
+sort of output is being produced, whether it be an executable file,
+an object file, an assembler file or preprocessed C code.
+
+Since only one output file can be specified, it does not make sense to
+use @option{-o} when compiling more than one input file, unless you are
+producing an executable file as output.
+
+If @option{-o} is not specified, the default is to put an executable file
+in @file{a.out}, the object file for @file{@var{source}.@var{suffix}} in
+@file{@var{source}.o}, its assembler file in @file{@var{source}.s}, and
+all preprocessed C source on standard output.
+
+@item -v
+@opindex v
+Print (on standard error output) the commands executed to run the stages
+of compilation.  Also print the version number of the compiler driver
+program and of the preprocessor and the compiler proper.
+
+@item -pipe
+@opindex pipe
+Use pipes rather than temporary files for communication between the
+various stages of compilation.  This fails to work on some systems where
+the assembler is unable to read from a pipe; but the GNU assembler has
+no trouble.
+
+@item --help
+@opindex help
+Print (on the standard output) a description of the command line options
+understood by @command{gcc}.  If the @option{-v} option is also specified
+then @option{--help} will also be passed on to the various processes
+invoked by @command{gcc}, so that they can display the command line options
+they accept.  If the @option{-W} option is also specified then command
+line options which have no documentation associated with them will also
+be displayed.
+
+@item --target-help
+@opindex target-help
+Print (on the standard output) a description of target specific command
+line options for each tool.
+@end table
+
+@node Invoking G++
+@section Compiling C++ Programs
+
+@cindex suffixes for C++ source
+@cindex C++ source file suffixes
+C++ source files conventionally use one of the suffixes @samp{.C},
+@samp{.cc}, @samp{.cpp}, @samp{.c++}, @samp{.cp}, or @samp{.cxx};
+preprocessed C++ files use the suffix @samp{.ii}.  GCC recognizes
+files with these names and compiles them as C++ programs even if you
+call the compiler the same way as for compiling C programs (usually with
+the name @command{gcc}).
+
+@findex g++
+@findex c++
+However, C++ programs often require class libraries as well as a
+compiler that understands the C++ language---and under some
+circumstances, you might want to compile programs from standard input,
+or otherwise without a suffix that flags them as C++ programs.
+@command{g++} is a program that calls GCC with the default language
+set to C++, and automatically specifies linking against the C++
+library.  On many systems, @command{g++} is also
+installed with the name @command{c++}.
+
+@cindex invoking @command{g++}
+When you compile C++ programs, you may specify many of the same
+command-line options that you use for compiling programs in any
+language; or command-line options meaningful for C and related
+languages; or options that are meaningful only for C++ programs.
+@xref{C Dialect Options,,Options Controlling C Dialect}, for
+explanations of options for languages related to C@.
+@xref{C++ Dialect Options,,Options Controlling C++ Dialect}, for
+explanations of options that are meaningful only for C++ programs.
+
+@node C Dialect Options
+@section Options Controlling C Dialect
+@cindex dialect options
+@cindex language dialect options
+@cindex options, dialect
+
+The following options control the dialect of C (or languages derived
+from C, such as C++ and Objective-C) that the compiler accepts:
+
+@table @gcctabopt
+@cindex ANSI support
+@cindex ISO support
+@item -ansi
+@opindex ansi
+In C mode, support all ISO C89 programs.  In C++ mode,
+remove GNU extensions that conflict with ISO C++.
+
+This turns off certain features of GCC that are incompatible with ISO
+C89 (when compiling C code), or of standard C++ (when compiling C++ code),
+such as the @code{asm} and @code{typeof} keywords, and
+predefined macros such as @code{unix} and @code{vax} that identify the
+type of system you are using.  It also enables the undesirable and
+rarely used ISO trigraph feature.  For the C compiler,
+it disables recognition of C++ style @samp{//} comments as well as
+the @code{inline} keyword.
+
+The alternate keywords @code{__asm__}, @code{__extension__},
+@code{__inline__} and @code{__typeof__} continue to work despite
+@option{-ansi}.  You would not want to use them in an ISO C program, of
+course, but it is useful to put them in header files that might be included
+in compilations done with @option{-ansi}.  Alternate predefined macros
+such as @code{__unix__} and @code{__vax__} are also available, with or
+without @option{-ansi}.
+
+The @option{-ansi} option does not cause non-ISO programs to be
+rejected gratuitously.  For that, @option{-pedantic} is required in
+addition to @option{-ansi}.  @xref{Warning Options}.
+
+The macro @code{__STRICT_ANSI__} is predefined when the @option{-ansi}
+option is used.  Some header files may notice this macro and refrain
+from declaring certain functions or defining certain macros that the
+ISO standard doesn't call for; this is to avoid interfering with any
+programs that might use these names for other things.
+
+Functions which would normally be built in but do not have semantics
+defined by ISO C (such as @code{alloca} and @code{ffs}) are not built-in
+functions with @option{-ansi} is used.  @xref{Other Builtins,,Other
+built-in functions provided by GCC}, for details of the functions
+affected.
+
+@item -std=
+@opindex std
+Determine the language standard.  This option is currently only
+supported when compiling C@.  A value for this option must be provided;
+possible values are
+
+@table @samp
+@item c89
+@itemx iso9899:1990
+ISO C89 (same as @option{-ansi}).
+
+@item iso9899:199409
+ISO C89 as modified in amendment 1.
+
+@item c99
+@itemx c9x
+@itemx iso9899:1999
+@itemx iso9899:199x
+ISO C99.  Note that this standard is not yet fully supported; see
+@w{@uref{http://gcc.gnu.org/c99status.html}} for more information.  The
+names @samp{c9x} and @samp{iso9899:199x} are deprecated.
+
+@item gnu89
+Default, ISO C89 plus GNU extensions (including some C99 features).
+
+@item gnu99
+@item gnu9x
+ISO C99 plus GNU extensions.  When ISO C99 is fully implemented in GCC,
+this will become the default.  The name @samp{gnu9x} is deprecated.
+
+@end table
+
+Even when this option is not specified, you can still use some of the
+features of newer standards in so far as they do not conflict with
+previous C standards.  For example, you may use @code{__restrict__} even
+when @option{-std=c99} is not specified.
+
+The @option{-std} options specifying some version of ISO C have the same
+effects as @option{-ansi}, except that features that were not in ISO C89
+but are in the specified version (for example, @samp{//} comments and
+the @code{inline} keyword in ISO C99) are not disabled.
+
+@xref{Standards,,Language Standards Supported by GCC}, for details of
+these standard versions.
+
+@item -aux-info @var{filename}
+@opindex aux-info
+Output to the given filename prototyped declarations for all functions
+declared and/or defined in a translation unit, including those in header
+files.  This option is silently ignored in any language other than C@.
+
+Besides declarations, the file indicates, in comments, the origin of
+each declaration (source file and line), whether the declaration was
+implicit, prototyped or unprototyped (@samp{I}, @samp{N} for new or
+@samp{O} for old, respectively, in the first character after the line
+number and the colon), and whether it came from a declaration or a
+definition (@samp{C} or @samp{F}, respectively, in the following
+character).  In the case of function definitions, a K&R-style list of
+arguments followed by their declarations is also provided, inside
+comments, after the declaration.
+
+@item -fno-asm
+@opindex fno-asm
+Do not recognize @code{asm}, @code{inline} or @code{typeof} as a
+keyword, so that code can use these words as identifiers.  You can use
+the keywords @code{__asm__}, @code{__inline__} and @code{__typeof__}
+instead.  @option{-ansi} implies @option{-fno-asm}.
+
+In C++, this switch only affects the @code{typeof} keyword, since
+@code{asm} and @code{inline} are standard keywords.  You may want to
+use the @option{-fno-gnu-keywords} flag instead, which has the same
+effect.  In C99 mode (@option{-std=c99} or @option{-std=gnu99}), this
+switch only affects the @code{asm} and @code{typeof} keywords, since
+@code{inline} is a standard keyword in ISO C99.
+
+@item -fno-builtin
+@itemx -fno-builtin-@var{function} @r{(C and Objective-C only)}
+@opindex fno-builtin
+@cindex built-in functions
+Don't recognize built-in functions that do not begin with
+@samp{__builtin_} as prefix.  @xref{Other Builtins,,Other built-in
+functions provided by GCC}, for details of the functions affected,
+including those which are not built-in functions when @option{-ansi} or
+@option{-std} options for strict ISO C conformance are used because they
+do not have an ISO standard meaning.
+
+GCC normally generates special code to handle certain built-in functions
+more efficiently; for instance, calls to @code{alloca} may become single
+instructions that adjust the stack directly, and calls to @code{memcpy}
+may become inline copy loops.  The resulting code is often both smaller
+and faster, but since the function calls no longer appear as such, you
+cannot set a breakpoint on those calls, nor can you change the behavior
+of the functions by linking with a different library.
+
+In C++, @option{-fno-builtin} is always in effect.  The @option{-fbuiltin}
+option has no effect.  Therefore, in C++, the only way to get the
+optimization benefits of built-in functions is to call the function
+using the @samp{__builtin_} prefix.  The GNU C++ Standard Library uses
+built-in functions to implement many functions (like
+@code{std::strchr}), so that you automatically get efficient code.
+
+With the @option{-fno-builtin-@var{function}} option, not available
+when compiling C++, only the built-in function @var{function} is
+disabled.  @var{function} must not begin with @samp{__builtin_}.  If a
+function is named this is not built-in in this version of GCC, this
+option is ignored.  There is no corresponding
+@option{-fbuiltin-@var{function}} option; if you wish to enable
+built-in functions selectively when using @option{-fno-builtin} or
+@option{-ffreestanding}, you may define macros such as:
+
+@smallexample
+#define abs(n)          __builtin_abs ((n))
+#define strcpy(d, s)    __builtin_strcpy ((d), (s))
+@end smallexample
+
+@item -fhosted
+@opindex fhosted
+@cindex hosted environment
+
+Assert that compilation takes place in a hosted environment.  This implies
+@option{-fbuiltin}.  A hosted environment is one in which the
+entire standard library is available, and in which @code{main} has a return
+type of @code{int}.  Examples are nearly everything except a kernel.
+This is equivalent to @option{-fno-freestanding}.
+
+@item -ffreestanding
+@opindex ffreestanding
+@cindex hosted environment
+
+Assert that compilation takes place in a freestanding environment.  This
+implies @option{-fno-builtin}.  A freestanding environment
+is one in which the standard library may not exist, and program startup may
+not necessarily be at @code{main}.  The most obvious example is an OS kernel.
+This is equivalent to @option{-fno-hosted}.
+
+@xref{Standards,,Language Standards Supported by GCC}, for details of
+freestanding and hosted environments.
+
+@item -trigraphs
+@opindex trigraphs
+Support ISO C trigraphs.  The @option{-ansi} option (and @option{-std}
+options for strict ISO C conformance) implies @option{-trigraphs}.
+
+@cindex traditional C language
+@cindex C language, traditional
+@item -traditional
+@opindex traditional
+Attempt to support some aspects of traditional C compilers.
+Specifically:
+
+@itemize @bullet
+@item
+All @code{extern} declarations take effect globally even if they
+are written inside of a function definition.  This includes implicit
+declarations of functions.
+
+@item
+The newer keywords @code{typeof}, @code{inline}, @code{signed}, @code{const}
+and @code{volatile} are not recognized.  (You can still use the
+alternative keywords such as @code{__typeof__}, @code{__inline__}, and
+so on.)
+
+@item
+Comparisons between pointers and integers are always allowed.
+
+@item
+Integer types @code{unsigned short} and @code{unsigned char} promote
+to @code{unsigned int}.
+
+@item
+Out-of-range floating point literals are not an error.
+
+@item
+Certain constructs which ISO regards as a single invalid preprocessing
+number, such as @samp{0xe-0xd}, are treated as expressions instead.
+
+@item
+String ``constants'' are not necessarily constant; they are stored in
+writable space, and identical looking constants are allocated
+separately.  (This is the same as the effect of
+@option{-fwritable-strings}.)
+
+@cindex @code{longjmp} and automatic variables
+@item
+All automatic variables not declared @code{register} are preserved by
+@code{longjmp}.  Ordinarily, GNU C follows ISO C: automatic variables
+not declared @code{volatile} may be clobbered.
+
+@item
+@cindex @samp{\x}
+@cindex @samp{\a}
+@cindex escape sequences, traditional
+The character escape sequences @samp{\x} and @samp{\a} evaluate as the
+literal characters @samp{x} and @samp{a} respectively.  Without
+@w{@option{-traditional}}, @samp{\x} is a prefix for the hexadecimal
+representation of a character, and @samp{\a} produces a bell.
+@end itemize
+
+This option is deprecated and may be removed.
+
+You may wish to use @option{-fno-builtin} as well as @option{-traditional}
+if your program uses names that are normally GNU C built-in functions for
+other purposes of its own.
+
+You cannot use @option{-traditional} if you include any header files that
+rely on ISO C features.  Some vendors are starting to ship systems with
+ISO C header files and you cannot use @option{-traditional} on such
+systems to compile files that include any system headers.
+
+The @option{-traditional} option also enables @option{-traditional-cpp}.
+
+@item -traditional-cpp
+@opindex traditional-cpp
+Attempt to support some aspects of traditional C preprocessors.
+See the GNU CPP manual for details.
+
+@item -fcond-mismatch
+@opindex fcond-mismatch
+Allow conditional expressions with mismatched types in the second and
+third arguments.  The value of such an expression is void.  This option
+is not supported for C++.
+
+@item -funsigned-char
+@opindex funsigned-char
+Let the type @code{char} be unsigned, like @code{unsigned char}.
+
+Each kind of machine has a default for what @code{char} should
+be.  It is either like @code{unsigned char} by default or like
+@code{signed char} by default.
+
+Ideally, a portable program should always use @code{signed char} or
+@code{unsigned char} when it depends on the signedness of an object.
+But many programs have been written to use plain @code{char} and
+expect it to be signed, or expect it to be unsigned, depending on the
+machines they were written for.  This option, and its inverse, let you
+make such a program work with the opposite default.
+
+The type @code{char} is always a distinct type from each of
+@code{signed char} or @code{unsigned char}, even though its behavior
+is always just like one of those two.
+
+@item -fsigned-char
+@opindex fsigned-char
+Let the type @code{char} be signed, like @code{signed char}.
+
+Note that this is equivalent to @option{-fno-unsigned-char}, which is
+the negative form of @option{-funsigned-char}.  Likewise, the option
+@option{-fno-signed-char} is equivalent to @option{-funsigned-char}.
+
+@item -fsigned-bitfields
+@itemx -funsigned-bitfields
+@itemx -fno-signed-bitfields
+@itemx -fno-unsigned-bitfields
+@opindex fsigned-bitfields
+@opindex funsigned-bitfields
+@opindex fno-signed-bitfields
+@opindex fno-unsigned-bitfields
+These options control whether a bit-field is signed or unsigned, when the
+declaration does not use either @code{signed} or @code{unsigned}.  By
+default, such a bit-field is signed, because this is consistent: the
+basic integer types such as @code{int} are signed types.
+
+However, when @option{-traditional} is used, bit-fields are all unsigned
+no matter what.
+
+@item -fwritable-strings
+@opindex fwritable-strings
+Store string constants in the writable data segment and don't uniquize
+them.  This is for compatibility with old programs which assume they can
+write into string constants.  The option @option{-traditional} also has
+this effect.
+
+Writing into string constants is a very bad idea; ``constants'' should
+be constant.
+
+@item -fallow-single-precision
+@opindex fallow-single-precision
+Do not promote single precision math operations to double precision,
+even when compiling with @option{-traditional}.
+
+Traditional K&R C promotes all floating point operations to double
+precision, regardless of the sizes of the operands.   On the
+architecture for which you are compiling, single precision may be faster
+than double precision.   If you must use @option{-traditional}, but want
+to use single precision operations when the operands are single
+precision, use this option.   This option has no effect when compiling
+with ISO or GNU C conventions (the default).
+
+@item -fshort-wchar
+@opindex fshort-wchar
+Override the underlying type for @samp{wchar_t} to be @samp{short
+unsigned int} instead of the default for the target.  This option is
+useful for building programs to run under WINE@.
+@end table
+
+@node C++ Dialect Options
+@section Options Controlling C++ Dialect
+
+@cindex compiler options, C++
+@cindex C++ options, command line
+@cindex options, C++
+This section describes the command-line options that are only meaningful
+for C++ programs; but you can also use most of the GNU compiler options
+regardless of what language your program is in.  For example, you
+might compile a file @code{firstClass.C} like this:
+
+@example
+g++ -g -frepo -O -c firstClass.C
+@end example
+
+@noindent
+In this example, only @option{-frepo} is an option meant
+only for C++ programs; you can use the other options with any
+language supported by GCC@.
+
+Here is a list of options that are @emph{only} for compiling C++ programs:
+
+@table @gcctabopt
+@item -fno-access-control
+@opindex fno-access-control
+Turn off all access checking.  This switch is mainly useful for working
+around bugs in the access control code.
+
+@item -fcheck-new
+@opindex fcheck-new
+Check that the pointer returned by @code{operator new} is non-null
+before attempting to modify the storage allocated.  The current Working
+Paper requires that @code{operator new} never return a null pointer, so
+this check is normally unnecessary.
+
+An alternative to using this option is to specify that your
+@code{operator new} does not throw any exceptions; if you declare it
+@samp{throw()}, G++ will check the return value.  See also @samp{new
+(nothrow)}.
+
+@item -fconserve-space
+@opindex fconserve-space
+Put uninitialized or runtime-initialized global variables into the
+common segment, as C does.  This saves space in the executable at the
+cost of not diagnosing duplicate definitions.  If you compile with this
+flag and your program mysteriously crashes after @code{main()} has
+completed, you may have an object that is being destroyed twice because
+two definitions were merged.
+
+This option is no longer useful on most targets, now that support has
+been added for putting variables into BSS without making them common.
+
+@item -fno-const-strings
+@opindex fno-const-strings
+Give string constants type @code{char *} instead of type @code{const
+char *}.  By default, G++ uses type @code{const char *} as required by
+the standard.  Even if you use @option{-fno-const-strings}, you cannot
+actually modify the value of a string constant, unless you also use
+@option{-fwritable-strings}.
+
+This option might be removed in a future release of G++.  For maximum
+portability, you should structure your code so that it works with
+string constants that have type @code{const char *}.
+
+@item -fdollars-in-identifiers
+@opindex fdollars-in-identifiers
+Accept @samp{$} in identifiers.  You can also explicitly prohibit use of
+@samp{$} with the option @option{-fno-dollars-in-identifiers}.  (GNU C allows
+@samp{$} by default on most target systems, but there are a few exceptions.)
+Traditional C allowed the character @samp{$} to form part of
+identifiers.  However, ISO C and C++ forbid @samp{$} in identifiers.
+
+@item -fno-elide-constructors
+@opindex fno-elide-constructors
+The C++ standard allows an implementation to omit creating a temporary
+which is only used to initialize another object of the same type.
+Specifying this option disables that optimization, and forces G++ to
+call the copy constructor in all cases.
+
+@item -fno-enforce-eh-specs
+@opindex fno-enforce-eh-specs
+Don't check for violation of exception specifications at runtime.  This
+option violates the C++ standard, but may be useful for reducing code
+size in production builds, much like defining @samp{NDEBUG}.  The compiler
+will still optimize based on the exception specifications.
+
+@item -fexternal-templates
+@opindex fexternal-templates
+
+Cause @samp{#pragma interface} and @samp{implementation} to apply to
+template instantiation; template instances are emitted or not according
+to the location of the template definition.  @xref{Template
+Instantiation}, for more information.
+
+This option is deprecated.
+
+@item -falt-external-templates
+@opindex falt-external-templates
+Similar to @option{-fexternal-templates}, but template instances are
+emitted or not according to the place where they are first instantiated.
+@xref{Template Instantiation}, for more information.
+
+This option is deprecated.
+
+@item -ffor-scope
+@itemx -fno-for-scope
+@opindex ffor-scope
+@opindex fno-for-scope
+If @option{-ffor-scope} is specified, the scope of variables declared in
+a @i{for-init-statement} is limited to the @samp{for} loop itself,
+as specified by the C++ standard.
+If @option{-fno-for-scope} is specified, the scope of variables declared in
+a @i{for-init-statement} extends to the end of the enclosing scope,
+as was the case in old versions of G++, and other (traditional)
+implementations of C++.
+
+The default if neither flag is given to follow the standard,
+but to allow and give a warning for old-style code that would
+otherwise be invalid, or have different behavior.
+
+@item -fno-gnu-keywords
+@opindex fno-gnu-keywords
+Do not recognize @code{typeof} as a keyword, so that code can use this
+word as an identifier.  You can use the keyword @code{__typeof__} instead.
+@option{-ansi} implies @option{-fno-gnu-keywords}.
+
+@item -fno-implicit-templates
+@opindex fno-implicit-templates
+Never emit code for non-inline templates which are instantiated
+implicitly (i.e.@: by use); only emit code for explicit instantiations.
+@xref{Template Instantiation}, for more information.
+
+@item -fno-implicit-inline-templates
+@opindex fno-implicit-inline-templates
+Don't emit code for implicit instantiations of inline templates, either.
+The default is to handle inlines differently so that compiles with and
+without optimization will need the same set of explicit instantiations.
+
+@item -fno-implement-inlines
+@opindex fno-implement-inlines
+To save space, do not emit out-of-line copies of inline functions
+controlled by @samp{#pragma implementation}.  This will cause linker
+errors if these functions are not inlined everywhere they are called.
+
+@item -fms-extensions
+@opindex fms-extensions
+Disable pedantic warnings about constructs used in MFC, such as implicit
+int and getting a pointer to member function via non-standard syntax.
+
+@item -fno-nonansi-builtins
+@opindex fno-nonansi-builtins
+Disable built-in declarations of functions that are not mandated by
+ANSI/ISO C@.  These include @code{ffs}, @code{alloca}, @code{_exit},
+@code{index}, @code{bzero}, @code{conjf}, and other related functions.
+
+@item -fno-operator-names
+@opindex fno-operator-names
+Do not treat the operator name keywords @code{and}, @code{bitand},
+@code{bitor}, @code{compl}, @code{not}, @code{or} and @code{xor} as
+synonyms as keywords.
+
+@item -fno-optional-diags
+@opindex fno-optional-diags
+Disable diagnostics that the standard says a compiler does not need to
+issue.  Currently, the only such diagnostic issued by G++ is the one for
+a name having multiple meanings within a class.
+
+@item -fpermissive
+@opindex fpermissive
+Downgrade messages about nonconformant code from errors to warnings.  By
+default, G++ effectively sets @option{-pedantic-errors} without
+@option{-pedantic}; this option reverses that.  This behavior and this
+option are superseded by @option{-pedantic}, which works as it does for GNU C@.
+
+@item -frepo
+@opindex frepo
+Enable automatic template instantiation at link time.  This option also
+implies @option{-fno-implicit-templates}.  @xref{Template
+Instantiation}, for more information.
+
+@item -fno-rtti
+@opindex fno-rtti
+Disable generation of information about every class with virtual
+functions for use by the C++ runtime type identification features
+(@samp{dynamic_cast} and @samp{typeid}).  If you don't use those parts
+of the language, you can save some space by using this flag.  Note that
+exception handling uses the same information, but it will generate it as
+needed.
+
+@item -fstats
+@opindex fstats
+Emit statistics about front-end processing at the end of the compilation.
+This information is generally only useful to the G++ development team.
+
+@item -ftemplate-depth-@var{n}
+@opindex ftemplate-depth
+Set the maximum instantiation depth for template classes to @var{n}.
+A limit on the template instantiation depth is needed to detect
+endless recursions during template class instantiation.  ANSI/ISO C++
+conforming programs must not rely on a maximum depth greater than 17.
+
+@item -fuse-cxa-atexit
+@opindex fuse-cxa-atexit
+Register destructors for objects with static storage duration with the
+@code{__cxa_atexit} function rather than the @code{atexit} function.
+This option is required for fully standards-compliant handling of static
+destructors, but will only work if your C library supports
+@code{__cxa_atexit}.
+
+@item -fvtable-gc
+@opindex fvtable-gc
+Emit special relocations for vtables and virtual function references
+so that the linker can identify unused virtual functions and zero out
+vtable slots that refer to them.  This is most useful with
+@option{-ffunction-sections} and @option{-Wl,--gc-sections}, in order to
+also discard the functions themselves.
+
+This optimization requires GNU as and GNU ld.  Not all systems support
+this option.  @option{-Wl,--gc-sections} is ignored without @option{-static}.
+
+@item -fno-weak
+@opindex fno-weak
+Do not use weak symbol support, even if it is provided by the linker.
+By default, G++ will use weak symbols if they are available.  This
+option exists only for testing, and should not be used by end-users;
+it will result in inferior code and has no benefits.  This option may
+be removed in a future release of G++.
+
+@item -nostdinc++
+@opindex nostdinc++
+Do not search for header files in the standard directories specific to
+C++, but do still search the other standard directories.  (This option
+is used when building the C++ library.)
+@end table
+
+In addition, these optimization, warning, and code generation options
+have meanings only for C++ programs:
+
+@table @gcctabopt
+@item -fno-default-inline
+@opindex fno-default-inline
+Do not assume @samp{inline} for functions defined inside a class scope.
+@xref{Optimize Options,,Options That Control Optimization}.  Note that these
+functions will have linkage like inline functions; they just won't be
+inlined by default.
+
+@item -Wctor-dtor-privacy @r{(C++ only)}
+@opindex Wctor-dtor-privacy
+Warn when a class seems unusable, because all the constructors or
+destructors in a class are private and the class has no friends or
+public static member functions.
+
+@item -Wnon-virtual-dtor @r{(C++ only)}
+@opindex Wnon-virtual-dtor
+Warn when a class declares a non-virtual destructor that should probably
+be virtual, because it looks like the class will be used polymorphically.
+
+@item -Wreorder @r{(C++ only)}
+@opindex Wreorder
+@cindex reordering, warning
+@cindex warning for reordering of member initializers
+Warn when the order of member initializers given in the code does not
+match the order in which they must be executed.  For instance:
+
+@smallexample
+struct A @{
+  int i;
+  int j;
+  A(): j (0), i (1) @{ @}
+@};
+@end smallexample
+
+Here the compiler will warn that the member initializers for @samp{i}
+and @samp{j} will be rearranged to match the declaration order of the
+members.
+@end table
+
+The following @option{-W@dots{}} options are not affected by @option{-Wall}.
+
+@table @gcctabopt
+@item -Weffc++ @r{(C++ only)}
+@opindex Weffc++
+Warn about violations of various style guidelines from Scott Meyers'
+@cite{Effective C++} books.  If you use this option, you should be aware
+that the standard library headers do not obey all of these guidelines;
+you can use @samp{grep -v} to filter out those warnings.
+
+@item -Wno-deprecated @r{(C++ only)}
+@opindex Wno-deprecated
+Do not warn about usage of deprecated features.  @xref{Deprecated Features}.
+
+@item -Wno-non-template-friend @r{(C++ only)}
+@opindex Wno-non-template-friend
+Disable warnings when non-templatized friend functions are declared
+within a template.  With the advent of explicit template specification
+support in G++, if the name of the friend is an unqualified-id (i.e.,
+@samp{friend foo(int)}), the C++ language specification demands that the
+friend declare or define an ordinary, nontemplate function.  (Section
+14.5.3).  Before G++ implemented explicit specification, unqualified-ids
+could be interpreted as a particular specialization of a templatized
+function.  Because this non-conforming behavior is no longer the default
+behavior for G++, @option{-Wnon-template-friend} allows the compiler to
+check existing code for potential trouble spots, and is on by default.
+This new compiler behavior can be turned off with
+@option{-Wno-non-template-friend} which keeps the conformant compiler code
+but disables the helpful warning.
+
+@item -Wold-style-cast @r{(C++ only)}
+@opindex Wold-style-cast
+Warn if an old-style (C-style) cast to a non-void type is used within
+a C++ program.  The new-style casts (@samp{static_cast},
+@samp{reinterpret_cast}, and @samp{const_cast}) are less vulnerable to
+unintended effects, and much easier to grep for.
+
+@item -Woverloaded-virtual @r{(C++ only)}
+@opindex Woverloaded-virtual
+@cindex overloaded virtual fn, warning
+@cindex warning for overloaded virtual fn
+Warn when a function declaration hides virtual functions from a
+base class.  For example, in:
+
+@smallexample
+struct A @{
+  virtual void f();
+@};
+
+struct B: public A @{
+  void f(int);
+@};
+@end smallexample
+
+the @code{A} class version of @code{f} is hidden in @code{B}, and code
+like this:
+
+@smallexample
+B* b;
+b->f();
+@end smallexample
+
+will fail to compile.
+
+@item -Wno-pmf-conversions @r{(C++ only)}
+@opindex Wno-pmf-conversions
+Disable the diagnostic for converting a bound pointer to member function
+to a plain pointer.
+
+@item -Wsign-promo @r{(C++ only)}
+@opindex Wsign-promo
+Warn when overload resolution chooses a promotion from unsigned or
+enumeral type to a signed type over a conversion to an unsigned type of
+the same size.  Previous versions of G++ would try to preserve
+unsignedness, but the standard mandates the current behavior.
+
+@item -Wsynth @r{(C++ only)}
+@opindex Wsynth
+@cindex warning for synthesized methods
+@cindex synthesized methods, warning
+Warn when G++'s synthesis behavior does not match that of cfront.  For
+instance:
+
+@smallexample
+struct A @{
+  operator int ();
+  A& operator = (int);
+@};
+
+main ()
+@{
+  A a,b;
+  a = b;
+@}
+@end smallexample
+
+In this example, G++ will synthesize a default @samp{A& operator =
+(const A&);}, while cfront will use the user-defined @samp{operator =}.
+@end table
+
+@node Objective-C Dialect Options
+@section Options Controlling Objective-C Dialect
+
+@cindex compiler options, Objective-C
+@cindex Objective-C options, command line
+@cindex options, Objective-C
+This section describes the command-line options that are only meaningful
+for Objective-C programs; but you can also use most of the GNU compiler
+options regardless of what language your program is in.  For example,
+you might compile a file @code{some_class.m} like this:
+
+@example
+gcc -g -fgnu-runtime -O -c some_class.m
+@end example
+
+@noindent
+In this example, only @option{-fgnu-runtime} is an option meant only for
+Objective-C programs; you can use the other options with any language
+supported by GCC@.
+
+Here is a list of options that are @emph{only} for compiling Objective-C
+programs:
+
+@table @gcctabopt
+@item -fconstant-string-class=@var{class-name}
+@opindex fconstant-string-class
+Use @var{class-name} as the name of the class to instantiate for each
+literal string specified with the syntax @code{@@"@dots{}"}.  The default
+class name is @code{NXConstantString}.
+
+@item -fgnu-runtime
+@opindex fgnu-runtime
+Generate object code compatible with the standard GNU Objective-C
+runtime.  This is the default for most types of systems.
+
+@item -fnext-runtime
+@opindex fnext-runtime
+Generate output compatible with the NeXT runtime.  This is the default
+for NeXT-based systems, including Darwin and Mac OS X@.
+
+@item -gen-decls
+@opindex gen-decls
+Dump interface declarations for all classes seen in the source file to a
+file named @file{@var{sourcename}.decl}.
+
+@item -Wno-protocol
+@opindex Wno-protocol
+Do not warn if methods required by a protocol are not implemented
+in the class adopting it.
+
+@item -Wselector
+@opindex Wselector
+Warn if a selector has multiple methods of different types defined.
+
+@c not documented because only avail via -Wp
+@c @item -print-objc-runtime-info
+
+@end table
+
+@node Language Independent Options
+@section Options to Control Diagnostic Messages Formatting
+@cindex options to control diagnostics formatting
+@cindex diagnostic messages
+@cindex message formatting
+
+Traditionally, diagnostic messages have been formatted irrespective of
+the output device's aspect (e.g.@: its width, @dots{}).  The options described
+below can be used to control the diagnostic messages formatting
+algorithm, e.g.@: how many characters per line, how often source location
+information should be reported.  Right now, only the C++ front end can
+honor these options.  However it is expected, in the near future, that
+the remaining front ends would be able to digest them correctly.
+
+@table @gcctabopt
+@item -fmessage-length=@var{n}
+@opindex fmessage-length
+Try to format error messages so that they fit on lines of about @var{n}
+characters.  The default is 72 characters for @command{g++} and 0 for the rest of
+the front ends supported by GCC@.  If @var{n} is zero, then no
+line-wrapping will be done; each error message will appear on a single
+line.
+
+@opindex fdiagnostics-show-location
+@item -fdiagnostics-show-location=once
+Only meaningful in line-wrapping mode.  Instructs the diagnostic messages
+reporter to emit @emph{once} source location information; that is, in
+case the message is too long to fit on a single physical line and has to
+be wrapped, the source location won't be emitted (as prefix) again,
+over and over, in subsequent continuation lines.  This is the default
+behavior.
+
+@item -fdiagnostics-show-location=every-line
+Only meaningful in line-wrapping mode.  Instructs the diagnostic
+messages reporter to emit the same source location information (as
+prefix) for physical lines that result from the process of breaking
+a message which is too long to fit on a single line.
+
+@end table
+
+@node Warning Options
+@section Options to Request or Suppress Warnings
+@cindex options to control warnings
+@cindex warning messages
+@cindex messages, warning
+@cindex suppressing warnings
+
+Warnings are diagnostic messages that report constructions which
+are not inherently erroneous but which are risky or suggest there
+may have been an error.
+
+You can request many specific warnings with options beginning @samp{-W},
+for example @option{-Wimplicit} to request warnings on implicit
+declarations.  Each of these specific warning options also has a
+negative form beginning @samp{-Wno-} to turn off warnings;
+for example, @option{-Wno-implicit}.  This manual lists only one of the
+two forms, whichever is not the default.
+
+These options control the amount and kinds of warnings produced by GCC:
+
+@table @gcctabopt
+@cindex syntax checking
+@item -fsyntax-only
+@opindex fsyntax-only
+Check the code for syntax errors, but don't do anything beyond that.
+
+@item -pedantic
+@opindex pedantic
+Issue all the warnings demanded by strict ISO C and ISO C++;
+reject all programs that use forbidden extensions, and some other
+programs that do not follow ISO C and ISO C++.  For ISO C, follows the
+version of the ISO C standard specified by any @option{-std} option used.
+
+Valid ISO C and ISO C++ programs should compile properly with or without
+this option (though a rare few will require @option{-ansi} or a
+@option{-std} option specifying the required version of ISO C)@.  However,
+without this option, certain GNU extensions and traditional C and C++
+features are supported as well.  With this option, they are rejected.
+
+@option{-pedantic} does not cause warning messages for use of the
+alternate keywords whose names begin and end with @samp{__}.  Pedantic
+warnings are also disabled in the expression that follows
+@code{__extension__}.  However, only system header files should use
+these escape routes; application programs should avoid them.
+@xref{Alternate Keywords}.
+
+Some users try to use @option{-pedantic} to check programs for strict ISO
+C conformance.  They soon find that it does not do quite what they want:
+it finds some non-ISO practices, but not all---only those for which
+ISO C @emph{requires} a diagnostic, and some others for which
+diagnostics have been added.
+
+A feature to report any failure to conform to ISO C might be useful in
+some instances, but would require considerable additional work and would
+be quite different from @option{-pedantic}.  We don't have plans to
+support such a feature in the near future.
+
+Where the standard specified with @option{-std} represents a GNU
+extended dialect of C, such as @samp{gnu89} or @samp{gnu99}, there is a
+corresponding @dfn{base standard}, the version of ISO C on which the GNU
+extended dialect is based.  Warnings from @option{-pedantic} are given
+where they are required by the base standard.  (It would not make sense
+for such warnings to be given only for features not in the specified GNU
+C dialect, since by definition the GNU dialects of C include all
+features the compiler supports with the given option, and there would be
+nothing to warn about.)
+
+@item -pedantic-errors
+@opindex pedantic-errors
+Like @option{-pedantic}, except that errors are produced rather than
+warnings.
+
+@item -w
+@opindex w
+Inhibit all warning messages.
+
+@item -Wno-import
+@opindex Wno-import
+Inhibit warning messages about the use of @samp{#import}.
+
+@item -Wchar-subscripts
+@opindex Wchar-subscripts
+Warn if an array subscript has type @code{char}.  This is a common cause
+of error, as programmers often forget that this type is signed on some
+machines.
+
+@item -Wcomment
+@opindex Wcomment
+Warn whenever a comment-start sequence @samp{/*} appears in a @samp{/*}
+comment, or whenever a Backslash-Newline appears in a @samp{//} comment.
+
+@item -Wformat
+@opindex Wformat
+Check calls to @code{printf} and @code{scanf}, etc., to make sure that
+the arguments supplied have types appropriate to the format string
+specified, and that the conversions specified in the format string make
+sense.  This includes standard functions, and others specified by format
+attributes (@pxref{Function Attributes}), in the @code{printf},
+@code{scanf}, @code{strftime} and @code{strfmon} (an X/Open extension,
+not in the C standard) families.
+
+The formats are checked against the format features supported by GNU
+libc version 2.2.  These include all ISO C89 and C99 features, as well
+as features from the Single Unix Specification and some BSD and GNU
+extensions.  Other library implementations may not support all these
+features; GCC does not support warning about features that go beyond a
+particular library's limitations.  However, if @option{-pedantic} is used
+with @option{-Wformat}, warnings will be given about format features not
+in the selected standard version (but not for @code{strfmon} formats,
+since those are not in any version of the C standard).  @xref{C Dialect
+Options,,Options Controlling C Dialect}.
+
+@option{-Wformat} is included in @option{-Wall}.  For more control over some
+aspects of format checking, the options @option{-Wno-format-y2k},
+@option{-Wno-format-extra-args}, @option{-Wformat-nonliteral},
+@option{-Wformat-security} and @option{-Wformat=2} are available, but are
+not included in @option{-Wall}.
+
+@item -Wno-format-y2k
+@opindex Wno-format-y2k
+If @option{-Wformat} is specified, do not warn about @code{strftime}
+formats which may yield only a two-digit year.
+
+@item -Wno-format-extra-args
+@opindex Wno-format-extra-args
+If @option{-Wformat} is specified, do not warn about excess arguments to a
+@code{printf} or @code{scanf} format function.  The C standard specifies
+that such arguments are ignored.
+
+Where the unused arguments lie between used arguments that are
+specified with @samp{$} operand number specifications, normally
+warnings are still given, since the implementation could not know what
+type to pass to @code{va_arg} to skip the unused arguments.  However,
+in the case of @code{scanf} formats, this option will suppress the
+warning if the unused arguments are all pointers, since the Single
+Unix Specification says that such unused arguments are allowed.
+
+@item -Wformat-nonliteral
+@opindex Wformat-nonliteral
+If @option{-Wformat} is specified, also warn if the format string is not a
+string literal and so cannot be checked, unless the format function
+takes its format arguments as a @code{va_list}.
+
+@item -Wformat-security
+@opindex Wformat-security
+If @option{-Wformat} is specified, also warn about uses of format
+functions that represent possible security problems.  At present, this
+warns about calls to @code{printf} and @code{scanf} functions where the
+format string is not a string literal and there are no format arguments,
+as in @code{printf (foo);}.  This may be a security hole if the format
+string came from untrusted input and contains @samp{%n}.  (This is
+currently a subset of what @option{-Wformat-nonliteral} warns about, but
+in future warnings may be added to @option{-Wformat-security} that are not
+included in @option{-Wformat-nonliteral}.)
+
+@item -Wformat=2
+@opindex Wformat=2
+Enable @option{-Wformat} plus format checks not included in
+@option{-Wformat}.  Currently equivalent to @samp{-Wformat
+-Wformat-nonliteral -Wformat-security}.
+
+@item -Wimplicit-int
+@opindex Wimplicit-int
+Warn when a declaration does not specify a type.
+
+@item -Wimplicit-function-declaration
+@itemx -Werror-implicit-function-declaration
+@opindex Wimplicit-function-declaration
+@opindex Werror-implicit-function-declaration
+Give a warning (or error) whenever a function is used before being
+declared.
+
+@item -Wimplicit
+@opindex Wimplicit
+Same as @option{-Wimplicit-int} and @option{-Wimplicit-function-declaration}.
+
+@item -Wmain
+@opindex Wmain
+Warn if the type of @samp{main} is suspicious.  @samp{main} should be a
+function with external linkage, returning int, taking either zero
+arguments, two, or three arguments of appropriate types.
+
+@item -Wmissing-braces
+@opindex Wmissing-braces
+Warn if an aggregate or union initializer is not fully bracketed.  In
+the following example, the initializer for @samp{a} is not fully
+bracketed, but that for @samp{b} is fully bracketed.
+
+@smallexample
+int a[2][2] = @{ 0, 1, 2, 3 @};
+int b[2][2] = @{ @{ 0, 1 @}, @{ 2, 3 @} @};
+@end smallexample
+
+@item -Wparentheses
+@opindex Wparentheses
+Warn if parentheses are omitted in certain contexts, such
+as when there is an assignment in a context where a truth value
+is expected, or when operators are nested whose precedence people
+often get confused about.
+
+Also warn about constructions where there may be confusion to which
+@code{if} statement an @code{else} branch belongs.  Here is an example of
+such a case:
+
+@smallexample
+@group
+@{
+  if (a)
+    if (b)
+      foo ();
+  else
+    bar ();
+@}
+@end group
+@end smallexample
+
+In C, every @code{else} branch belongs to the innermost possible @code{if}
+statement, which in this example is @code{if (b)}.  This is often not
+what the programmer expected, as illustrated in the above example by
+indentation the programmer chose.  When there is the potential for this
+confusion, GCC will issue a warning when this flag is specified.
+To eliminate the warning, add explicit braces around the innermost
+@code{if} statement so there is no way the @code{else} could belong to
+the enclosing @code{if}.  The resulting code would look like this:
+
+@smallexample
+@group
+@{
+  if (a)
+    @{
+      if (b)
+        foo ();
+      else
+        bar ();
+    @}
+@}
+@end group
+@end smallexample
+
+@item -Wsequence-point
+@opindex Wsequence-point
+Warn about code that may have undefined semantics because of violations
+of sequence point rules in the C standard.
+
+The C standard defines the order in which expressions in a C program are
+evaluated in terms of @dfn{sequence points}, which represent a partial
+ordering between the execution of parts of the program: those executed
+before the sequence point, and those executed after it.  These occur
+after the evaluation of a full expression (one which is not part of a
+larger expression), after the evaluation of the first operand of a
+@code{&&}, @code{||}, @code{? :} or @code{,} (comma) operator, before a
+function is called (but after the evaluation of its arguments and the
+expression denoting the called function), and in certain other places.
+Other than as expressed by the sequence point rules, the order of
+evaluation of subexpressions of an expression is not specified.  All
+these rules describe only a partial order rather than a total order,
+since, for example, if two functions are called within one expression
+with no sequence point between them, the order in which the functions
+are called is not specified.  However, the standards committee have
+ruled that function calls do not overlap.
+
+It is not specified when between sequence points modifications to the
+values of objects take effect.  Programs whose behavior depends on this
+have undefined behavior; the C standard specifies that ``Between the
+previous and next sequence point an object shall have its stored value
+modified at most once by the evaluation of an expression.  Furthermore,
+the prior value shall be read only to determine the value to be
+stored.''.  If a program breaks these rules, the results on any
+particular implementation are entirely unpredictable.
+
+Examples of code with undefined behavior are @code{a = a++;}, @code{a[n]
+= b[n++]} and @code{a[i++] = i;}.  Some more complicated cases are not
+diagnosed by this option, and it may give an occasional false positive
+result, but in general it has been found fairly effective at detecting
+this sort of problem in programs.
+
+The present implementation of this option only works for C programs.  A
+future implementation may also work for C++ programs.
+
+The C standard is worded confusingly, therefore there is some debate
+over the precise meaning of the sequence point rules in subtle cases.
+Links to discussions of the problem, including proposed formal
+definitions, may be found on our readings page, at
+@w{@uref{http://gcc.gnu.org/readings.html}}.
+
+@item -Wreturn-type
+@opindex Wreturn-type
+Warn whenever a function is defined with a return-type that defaults to
+@code{int}.  Also warn about any @code{return} statement with no
+return-value in a function whose return-type is not @code{void}.
+
+For C++, a function without return type always produces a diagnostic
+message, even when @option{-Wno-return-type} is specified.  The only
+exceptions are @samp{main} and functions defined in system headers.
+
+@item -Wswitch
+@opindex Wswitch
+Warn whenever a @code{switch} statement has an index of enumeral type
+and lacks a @code{case} for one or more of the named codes of that
+enumeration.  (The presence of a @code{default} label prevents this
+warning.)  @code{case} labels outside the enumeration range also
+provoke warnings when this option is used.
+
+@item -Wtrigraphs
+@opindex Wtrigraphs
+Warn if any trigraphs are encountered that might change the meaning of
+the program (trigraphs within comments are not warned about).
+
+@item -Wunused-function
+@opindex Wunused-function
+Warn whenever a static function is declared but not defined or a
+non\-inline static function is unused.
+
+@item -Wunused-label
+@opindex Wunused-label
+Warn whenever a label is declared but not used.
+
+To suppress this warning use the @samp{unused} attribute
+(@pxref{Variable Attributes}).
+
+@item -Wunused-parameter
+@opindex Wunused-parameter
+Warn whenever a function parameter is unused aside from its declaration.
+
+To suppress this warning use the @samp{unused} attribute
+(@pxref{Variable Attributes}).
+
+@item -Wunused-variable
+@opindex Wunused-variable
+Warn whenever a local variable or non-constant static variable is unused
+aside from its declaration
+
+To suppress this warning use the @samp{unused} attribute
+(@pxref{Variable Attributes}).
+
+@item -Wunused-value
+@opindex Wunused-value
+Warn whenever a statement computes a result that is explicitly not used.
+
+To suppress this warning cast the expression to @samp{void}.
+
+@item -Wunused
+@opindex Wunused
+All all the above @option{-Wunused} options combined.
+
+In order to get a warning about an unused function parameter, you must
+either specify @samp{-W -Wunused} or separately specify
+@option{-Wunused-parameter}.
+
+@item -Wuninitialized
+@opindex Wuninitialized
+Warn if an automatic variable is used without first being initialized or
+if a variable may be clobbered by a @code{setjmp} call.
+
+These warnings are possible only in optimizing compilation,
+because they require data flow information that is computed only
+when optimizing.  If you don't specify @option{-O}, you simply won't
+get these warnings.
+
+These warnings occur only for variables that are candidates for
+register allocation.  Therefore, they do not occur for a variable that
+is declared @code{volatile}, or whose address is taken, or whose size
+is other than 1, 2, 4 or 8 bytes.  Also, they do not occur for
+structures, unions or arrays, even when they are in registers.
+
+Note that there may be no warning about a variable that is used only
+to compute a value that itself is never used, because such
+computations may be deleted by data flow analysis before the warnings
+are printed.
+
+These warnings are made optional because GCC is not smart
+enough to see all the reasons why the code might be correct
+despite appearing to have an error.  Here is one example of how
+this can happen:
+
+@smallexample
+@group
+@{
+  int x;
+  switch (y)
+    @{
+    case 1: x = 1;
+      break;
+    case 2: x = 4;
+      break;
+    case 3: x = 5;
+    @}
+  foo (x);
+@}
+@end group
+@end smallexample
+
+@noindent
+If the value of @code{y} is always 1, 2 or 3, then @code{x} is
+always initialized, but GCC doesn't know this.  Here is
+another common case:
+
+@smallexample
+@{
+  int save_y;
+  if (change_y) save_y = y, y = new_y;
+  @dots{}
+  if (change_y) y = save_y;
+@}
+@end smallexample
+
+@noindent
+This has no bug because @code{save_y} is used only if it is set.
+
+@cindex @code{longjmp} warnings
+This option also warns when a non-volatile automatic variable might be
+changed by a call to @code{longjmp}.  These warnings as well are possible
+only in optimizing compilation.
+
+The compiler sees only the calls to @code{setjmp}.  It cannot know
+where @code{longjmp} will be called; in fact, a signal handler could
+call it at any point in the code.  As a result, you may get a warning
+even when there is in fact no problem because @code{longjmp} cannot
+in fact be called at the place which would cause a problem.
+
+Some spurious warnings can be avoided if you declare all the functions
+you use that never return as @code{noreturn}.  @xref{Function
+Attributes}.
+
+@item -Wreorder @r{(C++ only)}
+@opindex Wreorder
+@cindex reordering, warning
+@cindex warning for reordering of member initializers
+Warn when the order of member initializers given in the code does not
+match the order in which they must be executed.  For instance:
+
+@item -Wunknown-pragmas
+@opindex Wunknown-pragmas
+@cindex warning for unknown pragmas
+@cindex unknown pragmas, warning
+@cindex pragmas, warning of unknown
+Warn when a #pragma directive is encountered which is not understood by
+GCC@.  If this command line option is used, warnings will even be issued
+for unknown pragmas in system header files.  This is not the case if
+the warnings were only enabled by the @option{-Wall} command line option.
+
+@item -Wall
+@opindex Wall
+All of the above @samp{-W} options combined.  This enables all the
+warnings about constructions that some users consider questionable, and
+that are easy to avoid (or modify to prevent the warning), even in
+conjunction with macros.
+
+@item -Wdiv-by-zero
+@opindex Wno-div-by-zero
+@opindex Wdiv-by-zero
+Warn about compile-time integer division by zero.  This is default.  To
+inhibit the warning messages, use @option{-Wno-div-by-zero}.  Floating
+point division by zero is not warned about, as it can be a legitimate
+way of obtaining infinities and NaNs.
+
+@item -Wmultichar
+@opindex Wno-multichar
+@opindex Wmultichar
+Warn if a multicharacter constant (@samp{'FOOF'}) is used.  This is
+default.  To inhibit the warning messages, use @option{-Wno-multichar}.
+Usually they indicate a typo in the user's code, as they have
+implementation-defined values, and should not be used in portable code.
+
+@item -Wsystem-headers
+@opindex Wsystem-headers
+@cindex warnings from system headers
+@cindex system headers, warnings from
+Print warning messages for constructs found in system header files.
+Warnings from system headers are normally suppressed, on the assumption
+that they usually do not indicate real problems and would only make the
+compiler output harder to read.  Using this command line option tells
+GCC to emit warnings from system headers as if they occurred in user
+code.  However, note that using @option{-Wall} in conjunction with this
+option will @emph{not} warn about unknown pragmas in system
+headers---for that, @option{-Wunknown-pragmas} must also be used.
+@end table
+
+The following @option{-W@dots{}} options are not implied by @option{-Wall}.
+Some of them warn about constructions that users generally do not
+consider questionable, but which occasionally you might wish to check
+for; others warn about constructions that are necessary or hard to avoid
+in some cases, and there is no simple way to modify the code to suppress
+the warning.
+
+@table @gcctabopt
+@item -W
+@opindex W
+Print extra warning messages for these events:
+
+@itemize @bullet
+@item
+A function can return either with or without a value.  (Falling
+off the end of the function body is considered returning without
+a value.)  For example, this function would evoke such a
+warning:
+
+@smallexample
+@group
+foo (a)
+@{
+  if (a > 0)
+    return a;
+@}
+@end group
+@end smallexample
+
+@item
+An expression-statement or the left-hand side of a comma expression
+contains no side effects.
+To suppress the warning, cast the unused expression to void.
+For example, an expression such as @samp{x[i,j]} will cause a warning,
+but @samp{x[(void)i,j]} will not.
+
+@item
+An unsigned value is compared against zero with @samp{<} or @samp{<=}.
+
+@item
+A comparison like @samp{x<=y<=z} appears; this is equivalent to
+@samp{(x<=y ? 1 : 0) <= z}, which is a different interpretation from
+that of ordinary mathematical notation.
+
+@item
+Storage-class specifiers like @code{static} are not the first things in
+a declaration.  According to the C Standard, this usage is obsolescent.
+
+@item
+The return type of a function has a type qualifier such as @code{const}.
+Such a type qualifier has no effect, since the value returned by a
+function is not an lvalue.  (But don't warn about the GNU extension of
+@code{volatile void} return types.  That extension will be warned about
+if @option{-pedantic} is specified.)
+
+@item
+If @option{-Wall} or @option{-Wunused} is also specified, warn about unused
+arguments.
+
+@item
+A comparison between signed and unsigned values could produce an
+incorrect result when the signed value is converted to unsigned.
+(But don't warn if @option{-Wno-sign-compare} is also specified.)
+
+@item
+An aggregate has a partly bracketed initializer.
+For example, the following code would evoke such a warning,
+because braces are missing around the initializer for @code{x.h}:
+
+@smallexample
+struct s @{ int f, g; @};
+struct t @{ struct s h; int i; @};
+struct t x = @{ 1, 2, 3 @};
+@end smallexample
+
+@item
+An aggregate has an initializer which does not initialize all members.
+For example, the following code would cause such a warning, because
+@code{x.h} would be implicitly initialized to zero:
+
+@smallexample
+struct s @{ int f, g, h; @};
+struct s x = @{ 3, 4 @};
+@end smallexample
+@end itemize
+
+@item -Wfloat-equal
+@opindex Wfloat-equal
+Warn if floating point values are used in equality comparisons.
+
+The idea behind this is that sometimes it is convenient (for the
+programmer) to consider floating-point values as approximations to
+infinitely precise real numbers.  If you are doing this, then you need
+to compute (by analysing the code, or in some other way) the maximum or
+likely maximum error that the computation introduces, and allow for it
+when performing comparisons (and when producing output, but that's a
+different problem).  In particular, instead of testing for equality, you
+would check to see whether the two values have ranges that overlap; and
+this is done with the relational operators, so equality comparisons are
+probably mistaken.
+
+@item -Wtraditional @r{(C only)}
+@opindex Wtraditional
+Warn about certain constructs that behave differently in traditional and
+ISO C@.  Also warn about ISO C constructs that have no traditional C
+equivalent, and/or problematic constructs which should be avoided.
+
+@itemize @bullet
+@item
+Macro parameters that appear within string literals in the macro body.
+In traditional C macro replacement takes place within string literals,
+but does not in ISO C@.
+
+@item
+In traditional C, some preprocessor directives did not exist.
+Traditional preprocessors would only consider a line to be a directive
+if the @samp{#} appeared in column 1 on the line.  Therefore
+@option{-Wtraditional} warns about directives that traditional C
+understands but would ignore because the @samp{#} does not appear as the
+first character on the line.  It also suggests you hide directives like
+@samp{#pragma} not understood by traditional C by indenting them.  Some
+traditional implementations would not recognize @samp{#elif}, so it
+suggests avoiding it altogether.
+
+@item
+A function-like macro that appears without arguments.
+
+@item
+The unary plus operator.
+
+@item
+The @samp{U} integer constant suffix, or the @samp{F} or @samp{L} floating point
+constant suffixes.  (Traditional C does support the @samp{L} suffix on integer
+constants.)  Note, these suffixes appear in macros defined in the system
+headers of most modern systems, e.g.@: the @samp{_MIN}/@samp{_MAX} macros in @code{<limits.h>}.
+Use of these macros in user code might normally lead to spurious
+warnings, however gcc's integrated preprocessor has enough context to
+avoid warning in these cases.
+
+@item
+A function declared external in one block and then used after the end of
+the block.
+
+@item
+A @code{switch} statement has an operand of type @code{long}.
+
+@item
+A non-@code{static} function declaration follows a @code{static} one.
+This construct is not accepted by some traditional C compilers.
+
+@item
+The ISO type of an integer constant has a different width or
+signedness from its traditional type.  This warning is only issued if
+the base of the constant is ten.  I.e.@: hexadecimal or octal values, which
+typically represent bit patterns, are not warned about.
+
+@item
+Usage of ISO string concatenation is detected.
+
+@item
+Initialization of automatic aggregates.
+
+@item
+Identifier conflicts with labels.  Traditional C lacks a separate
+namespace for labels.
+
+@item
+Initialization of unions.  If the initializer is zero, the warning is
+omitted.  This is done under the assumption that the zero initializer in
+user code appears conditioned on e.g.@: @code{__STDC__} to avoid missing
+initializer warnings and relies on default initialization to zero in the
+traditional C case.
+
+@item
+Conversions by prototypes between fixed/floating point values and vice
+versa.  The absence of these prototypes when compiling with traditional
+C would cause serious problems.  This is a subset of the possible
+conversion warnings, for the full set use @option{-Wconversion}.
+@end itemize
+
+@item -Wundef
+@opindex Wundef
+Warn if an undefined identifier is evaluated in an @samp{#if} directive.
+
+@item -Wshadow
+@opindex Wshadow
+Warn whenever a local variable shadows another local variable, parameter or
+global variable or whenever a built-in function is shadowed.
+
+@item -Wlarger-than-@var{len}
+@opindex Wlarger-than
+Warn whenever an object of larger than @var{len} bytes is defined.
+
+@item -Wpointer-arith
+@opindex Wpointer-arith
+Warn about anything that depends on the ``size of'' a function type or
+of @code{void}.  GNU C assigns these types a size of 1, for
+convenience in calculations with @code{void *} pointers and pointers
+to functions.
+
+@item -Wbad-function-cast @r{(C only)}
+@opindex Wbad-function-cast
+Warn whenever a function call is cast to a non-matching type.
+For example, warn if @code{int malloc()} is cast to @code{anything *}.
+
+@item -Wcast-qual
+@opindex Wcast-qual
+Warn whenever a pointer is cast so as to remove a type qualifier from
+the target type.  For example, warn if a @code{const char *} is cast
+to an ordinary @code{char *}.
+
+@item -Wcast-align
+@opindex Wcast-align
+Warn whenever a pointer is cast such that the required alignment of the
+target is increased.  For example, warn if a @code{char *} is cast to
+an @code{int *} on machines where integers can only be accessed at
+two- or four-byte boundaries.
+
+@item -Wwrite-strings
+@opindex Wwrite-strings
+When compiling C, give string constants the type @code{const
+char[@var{length}]} so that
+copying the address of one into a non-@code{const} @code{char *}
+pointer will get a warning; when compiling C++, warn about the
+deprecated conversion from string constants to @code{char *}.
+These warnings will help you find at
+compile time code that can try to write into a string constant, but
+only if you have been very careful about using @code{const} in
+declarations and prototypes.  Otherwise, it will just be a nuisance;
+this is why we did not make @option{-Wall} request these warnings.
+
+@item -Wconversion
+@opindex Wconversion
+Warn if a prototype causes a type conversion that is different from what
+would happen to the same argument in the absence of a prototype.  This
+includes conversions of fixed point to floating and vice versa, and
+conversions changing the width or signedness of a fixed point argument
+except when the same as the default promotion.
+
+Also, warn if a negative integer constant expression is implicitly
+converted to an unsigned type.  For example, warn about the assignment
+@code{x = -1} if @code{x} is unsigned.  But do not warn about explicit
+casts like @code{(unsigned) -1}.
+
+@item -Wsign-compare
+@opindex Wsign-compare
+@cindex warning for comparison of signed and unsigned values
+@cindex comparison of signed and unsigned values, warning
+@cindex signed and unsigned values, comparison warning
+Warn when a comparison between signed and unsigned values could produce
+an incorrect result when the signed value is converted to unsigned.
+This warning is also enabled by @option{-W}; to get the other warnings
+of @option{-W} without this warning, use @samp{-W -Wno-sign-compare}.
+
+@item -Waggregate-return
+@opindex Waggregate-return
+Warn if any functions that return structures or unions are defined or
+called.  (In languages where you can return an array, this also elicits
+a warning.)
+
+@item -Wstrict-prototypes @r{(C only)}
+@opindex Wstrict-prototypes
+Warn if a function is declared or defined without specifying the
+argument types.  (An old-style function definition is permitted without
+a warning if preceded by a declaration which specifies the argument
+types.)
+
+@item -Wmissing-prototypes @r{(C only)}
+@opindex Wmissing-prototypes
+Warn if a global function is defined without a previous prototype
+declaration.  This warning is issued even if the definition itself
+provides a prototype.  The aim is to detect global functions that fail
+to be declared in header files.
+
+@item -Wmissing-declarations
+@opindex Wmissing-declarations
+Warn if a global function is defined without a previous declaration.
+Do so even if the definition itself provides a prototype.
+Use this option to detect global functions that are not declared in
+header files.
+
+@item -Wmissing-noreturn
+@opindex Wmissing-noreturn
+Warn about functions which might be candidates for attribute @code{noreturn}.
+Note these are only possible candidates, not absolute ones.  Care should
+be taken to manually verify functions actually do not ever return before
+adding the @code{noreturn} attribute, otherwise subtle code generation
+bugs could be introduced.  You will not get a warning for @code{main} in
+hosted C environments.
+
+@item -Wmissing-format-attribute
+@opindex Wmissing-format-attribute
+@opindex Wformat
+If @option{-Wformat} is enabled, also warn about functions which might be
+candidates for @code{format} attributes.  Note these are only possible
+candidates, not absolute ones.  GCC will guess that @code{format}
+attributes might be appropriate for any function that calls a function
+like @code{vprintf} or @code{vscanf}, but this might not always be the
+case, and some functions for which @code{format} attributes are
+appropriate may not be detected.  This option has no effect unless
+@option{-Wformat} is enabled (possibly by @option{-Wall}).
+
+@item -Wno-deprecated-declarations
+@opindex Wno-deprecated-declarations
+Do not warn about uses of functions, variables, and types marked as
+deprecated by using the @code{deprecated} attribute. 
+(@pxref{Function Attributes}, @pxref{Variable Attributes},
+@pxref{Type Attributes}.)
+
+@item -Wpacked
+@opindex Wpacked
+Warn if a structure is given the packed attribute, but the packed
+attribute has no effect on the layout or size of the structure.
+Such structures may be mis-aligned for little benefit.  For
+instance, in this code, the variable @code{f.x} in @code{struct bar}
+will be misaligned even though @code{struct bar} does not itself
+have the packed attribute:
+
+@smallexample
+@group
+struct foo @{
+  int x;
+  char a, b, c, d;
+@} __attribute__((packed));
+struct bar @{
+  char z;
+  struct foo f;
+@};
+@end group
+@end smallexample
+
+@item -Wpadded
+@opindex Wpadded
+Warn if padding is included in a structure, either to align an element
+of the structure or to align the whole structure.  Sometimes when this
+happens it is possible to rearrange the fields of the structure to
+reduce the padding and so make the structure smaller.
+
+@item -Wredundant-decls
+@opindex Wredundant-decls
+Warn if anything is declared more than once in the same scope, even in
+cases where multiple declaration is valid and changes nothing.
+
+@item -Wnested-externs @r{(C only)}
+@opindex Wnested-externs
+Warn if an @code{extern} declaration is encountered within a function.
+
+@item -Wunreachable-code
+@opindex Wunreachable-code
+Warn if the compiler detects that code will never be executed.
+
+This option is intended to warn when the compiler detects that at
+least a whole line of source code will never be executed, because
+some condition is never satisfied or because it is after a
+procedure that never returns.
+
+It is possible for this option to produce a warning even though there
+are circumstances under which part of the affected line can be executed,
+so care should be taken when removing apparently-unreachable code.
+
+For instance, when a function is inlined, a warning may mean that the
+line is unreachable in only one inlined copy of the function.
+
+This option is not made part of @option{-Wall} because in a debugging
+version of a program there is often substantial code which checks
+correct functioning of the program and is, hopefully, unreachable
+because the program does work.  Another common use of unreachable
+code is to provide behavior which is selectable at compile-time.
+
+@item -Winline
+@opindex Winline
+Warn if a function can not be inlined and it was declared as inline.
+
+@item -Wlong-long
+@opindex Wlong-long
+@opindex Wno-long-long
+Warn if @samp{long long} type is used.  This is default.  To inhibit
+the warning messages, use @option{-Wno-long-long}.  Flags
+@option{-Wlong-long} and @option{-Wno-long-long} are taken into account
+only when @option{-pedantic} flag is used.
+
+@item -Wdisabled-optimization
+@opindex Wdisabled-optimization
+Warn if a requested optimization pass is disabled.  This warning does
+not generally indicate that there is anything wrong with your code; it
+merely indicates that GCC's optimizers were unable to handle the code
+effectively.  Often, the problem is that your code is too big or too
+complex; GCC will refuse to optimize programs when the optimization
+itself is likely to take inordinate amounts of time.
+
+@item -Werror
+@opindex Werror
+Make all warnings into errors.
+@end table
+
+@node Debugging Options
+@section Options for Debugging Your Program or GCC
+@cindex options, debugging
+@cindex debugging information options
+
+GCC has various special options that are used for debugging
+either your program or GCC:
+
+@table @gcctabopt
+@item -g
+@opindex g
+Produce debugging information in the operating system's native format
+(stabs, COFF, XCOFF, or DWARF)@.  GDB can work with this debugging
+information.
+
+On most systems that use stabs format, @option{-g} enables use of extra
+debugging information that only GDB can use; this extra information
+makes debugging work better in GDB but will probably make other debuggers
+crash or
+refuse to read the program.  If you want to control for certain whether
+to generate the extra information, use @option{-gstabs+}, @option{-gstabs},
+@option{-gxcoff+}, @option{-gxcoff}, @option{-gdwarf-1+}, @option{-gdwarf-1},
+or @option{-gvms} (see below).
+
+Unlike most other C compilers, GCC allows you to use @option{-g} with
+@option{-O}.  The shortcuts taken by optimized code may occasionally
+produce surprising results: some variables you declared may not exist
+at all; flow of control may briefly move where you did not expect it;
+some statements may not be executed because they compute constant
+results or their values were already at hand; some statements may
+execute in different places because they were moved out of loops.
+
+Nevertheless it proves possible to debug optimized output.  This makes
+it reasonable to use the optimizer for programs that might have bugs.
+
+The following options are useful when GCC is generated with the
+capability for more than one debugging format.
+
+@item -ggdb
+@opindex ggdb
+Produce debugging information for use by GDB@.  This means to use the
+most expressive format available (DWARF 2, stabs, or the native format
+if neither of those are supported), including GDB extensions if at all
+possible.
+
+@item -gstabs
+@opindex gstabs
+Produce debugging information in stabs format (if that is supported),
+without GDB extensions.  This is the format used by DBX on most BSD
+systems.  On MIPS, Alpha and System V Release 4 systems this option
+produces stabs debugging output which is not understood by DBX or SDB@.
+On System V Release 4 systems this option requires the GNU assembler.
+
+@item -gstabs+
+@opindex gstabs+
+Produce debugging information in stabs format (if that is supported),
+using GNU extensions understood only by the GNU debugger (GDB)@.  The
+use of these extensions is likely to make other debuggers crash or
+refuse to read the program.
+
+@item -gcoff
+@opindex gcoff
+Produce debugging information in COFF format (if that is supported).
+This is the format used by SDB on most System V systems prior to
+System V Release 4.
+
+@item -gxcoff
+@opindex gxcoff
+Produce debugging information in XCOFF format (if that is supported).
+This is the format used by the DBX debugger on IBM RS/6000 systems.
+
+@item -gxcoff+
+@opindex gxcoff+
+Produce debugging information in XCOFF format (if that is supported),
+using GNU extensions understood only by the GNU debugger (GDB)@.  The
+use of these extensions is likely to make other debuggers crash or
+refuse to read the program, and may cause assemblers other than the GNU
+assembler (GAS) to fail with an error.
+
+@item -gdwarf
+@opindex gdwarf
+Produce debugging information in DWARF version 1 format (if that is
+supported).  This is the format used by SDB on most System V Release 4
+systems.
+
+@item -gdwarf+
+@opindex gdwarf+
+Produce debugging information in DWARF version 1 format (if that is
+supported), using GNU extensions understood only by the GNU debugger
+(GDB)@.  The use of these extensions is likely to make other debuggers
+crash or refuse to read the program.
+
+@item -gdwarf-2
+@opindex gdwarf-2
+Produce debugging information in DWARF version 2 format (if that is
+supported).  This is the format used by DBX on IRIX 6.
+
+@item -gvms
+@opindex gvms
+Produce debugging information in VMS debug format (if that is
+supported).  This is the format used by DEBUG on VMS systems.
+
+@item -g@var{level}
+@itemx -ggdb@var{level}
+@itemx -gstabs@var{level}
+@itemx -gcoff@var{level}
+@itemx -gxcoff@var{level}
+@itemx -gdwarf@var{level}
+@itemx -gdwarf-2@var{level}
+@itemx -gvms@var{level}
+Request debugging information and also use @var{level} to specify how
+much information.  The default level is 2.
+
+Level 1 produces minimal information, enough for making backtraces in
+parts of the program that you don't plan to debug.  This includes
+descriptions of functions and external variables, but no information
+about local variables and no line numbers.
+
+Level 3 includes extra information, such as all the macro definitions
+present in the program.  Some debuggers support macro expansion when
+you use @option{-g3}.
+
+@cindex @code{prof}
+@item -p
+@opindex p
+Generate extra code to write profile information suitable for the
+analysis program @code{prof}.  You must use this option when compiling
+the source files you want data about, and you must also use it when
+linking.
+
+@cindex @code{gprof}
+@item -pg
+@opindex pg
+Generate extra code to write profile information suitable for the
+analysis program @code{gprof}.  You must use this option when compiling
+the source files you want data about, and you must also use it when
+linking.
+
+@cindex @code{tcov}
+@item -a
+@opindex a
+Generate extra code to write profile information for basic blocks, which will
+record the number of times each basic block is executed, the basic block start
+address, and the function name containing the basic block.  If @option{-g} is
+used, the line number and filename of the start of the basic block will also be
+recorded.  If not overridden by the machine description, the default action is
+to append to the text file @file{bb.out}.
+
+This data could be analyzed by a program like @code{tcov}.  Note,
+however, that the format of the data is not what @code{tcov} expects.
+Eventually GNU @code{gprof} should be extended to process this data.
+
+@item -Q
+@opindex Q
+Makes the compiler print out each function name as it is compiled, and
+print some statistics about each pass when it finishes.
+
+@item -ftime-report
+@opindex ftime-report
+Makes the compiler print some statistics about the time consumed by each
+pass when it finishes.
+
+@item -fmem-report
+@opindex fmem-report
+Makes the compiler print some statistics about permanent memory
+allocation when it finishes.
+
+@item -fprofile-arcs
+@opindex fprofile-arcs
+Instrument @dfn{arcs} during compilation to generate coverage data
+or for profile-directed block ordering.  During execution the program
+records how many times each branch is executed and how many times it is
+taken.  When the compiled program exits it saves this data to a file
+called @file{@var{sourcename}.da} for each source file.
+
+For profile-directed block ordering, compile the program with
+@option{-fprofile-arcs} plus optimization and code generation options,
+generate the arc profile information by running the program on a
+selected workload, and then compile the program again with the same
+optimization and code generation options plus
+@option{-fbranch-probabilities} (@pxref{Optimize Options,,Options that
+Control Optimization}).
+
+The other use of @option{-fprofile-arcs} is for use with @code{gcov},
+when it is used with the @option{-ftest-coverage} option.  GCC
+supports two methods of determining code coverage: the options that
+support @code{gcov}, and options @option{-a} and @option{-ax}, which
+write information to text files.  The options that support @code{gcov}
+do not need to instrument every arc in the program, so a program compiled
+with them runs faster than a program compiled with @option{-a}, which
+adds instrumentation code to every basic block in the program.  The
+tradeoff: since @code{gcov} does not have execution counts for all
+branches, it must start with the execution counts for the instrumented
+branches, and then iterate over the program flow graph until the entire
+graph has been solved.  Hence, @code{gcov} runs a little more slowly than
+a program which uses information from @option{-a} and @option{-ax}.
+
+With @option{-fprofile-arcs}, for each function of your program GCC
+creates a program flow graph, then finds a spanning tree for the graph.
+Only arcs that are not on the spanning tree have to be instrumented: the
+compiler adds code to count the number of times that these arcs are
+executed.  When an arc is the only exit or only entrance to a block, the
+instrumentation code can be added to the block; otherwise, a new basic
+block must be created to hold the instrumentation code.
+
+This option makes it possible to estimate branch probabilities and to
+calculate basic block execution counts.  In general, basic block
+execution counts as provided by @option{-a} do not give enough
+information to estimate all branch probabilities.
+
+@need 2000
+@item -ftest-coverage
+@opindex ftest-coverage
+Create data files for the @code{gcov} code-coverage utility
+(@pxref{Gcov,, @code{gcov}: a GCC Test Coverage Program}).
+The data file names begin with the name of your source file:
+
+@table @gcctabopt
+@item @var{sourcename}.bb
+A mapping from basic blocks to line numbers, which @code{gcov} uses to
+associate basic block execution counts with line numbers.
+
+@item @var{sourcename}.bbg
+A list of all arcs in the program flow graph.  This allows @code{gcov}
+to reconstruct the program flow graph, so that it can compute all basic
+block and arc execution counts from the information in the
+@code{@var{sourcename}.da} file.
+@end table
+
+Use @option{-ftest-coverage} with @option{-fprofile-arcs}; the latter
+option adds instrumentation to the program, which then writes
+execution counts to another data file:
+
+@table @gcctabopt
+@item @var{sourcename}.da
+Runtime arc execution counts, used in conjunction with the arc
+information in the file @code{@var{sourcename}.bbg}.
+@end table
+
+Coverage data will map better to the source files if
+@option{-ftest-coverage} is used without optimization.
+
+@item -d@var{letters}
+@opindex d
+Says to make debugging dumps during compilation at times specified by
+@var{letters}.  This is used for debugging the compiler.  The file names
+for most of the dumps are made by appending a pass number and a word to
+the source file name (e.g.  @file{foo.c.00.rtl} or @file{foo.c.01.sibling}).
+Here are the possible letters for use in @var{letters}, and their meanings:
+
+@table @samp
+@item A
+@opindex dA
+Annotate the assembler output with miscellaneous debugging information.
+@item b
+@opindex db
+Dump after computing branch probabilities, to @file{@var{file}.14.bp}.
+@item B
+@opindex dB
+Dump after block reordering, to @file{@var{file}.29.bbro}.
+@item c
+@opindex dc
+Dump after instruction combination, to the file @file{@var{file}.16.combine}.
+@item C
+@opindex dC
+Dump after the first if conversion, to the file @file{@var{file}.17.ce}.
+@item d
+@opindex dd
+Dump after delayed branch scheduling, to @file{@var{file}.31.dbr}.
+@item D
+@opindex dD
+Dump all macro definitions, at the end of preprocessing, in addition to
+normal output.
+@item e
+@opindex de
+Dump after SSA optimizations, to @file{@var{file}.04.ssa} and
+@file{@var{file}.07.ussa}.
+@item E
+@opindex dE
+Dump after the second if conversion, to @file{@var{file}.26.ce2}.
+@item f
+@opindex df
+Dump after life analysis, to @file{@var{file}.15.life}.
+@item F
+@opindex dF
+Dump after purging @code{ADDRESSOF} codes, to @file{@var{file}.09.addressof}.
+@item g
+@opindex dg
+Dump after global register allocation, to @file{@var{file}.21.greg}.
+@item h
+@opindex dh
+Dump after finalization of EH handling code, to @file{@var{file}.02.eh}.
+@item k
+@opindex dk
+Dump after reg-to-stack conversion, to @file{@var{file}.28.stack}.
+@item o
+@opindex do
+Dump after post-reload optimizations, to @file{@var{file}.22.postreload}.
+@item G
+@opindex dG
+Dump after GCSE, to @file{@var{file}.10.gcse}.
+@item i
+@opindex di
+Dump after sibling call optimizations, to @file{@var{file}.01.sibling}.
+@item j
+@opindex dj
+Dump after the first jump optimization, to @file{@var{file}.03.jump}.
+@item k
+@opindex dk
+Dump after conversion from registers to stack, to @file{@var{file}.32.stack}.
+@item l
+@opindex dl
+Dump after local register allocation, to @file{@var{file}.20.lreg}.
+@item L
+@opindex dL
+Dump after loop optimization, to @file{@var{file}.11.loop}.
+@item M
+@opindex dM
+Dump after performing the machine dependent reorganisation pass, to
+@file{@var{file}.30.mach}.
+@item n
+@opindex dn
+Dump after register renumbering, to @file{@var{file}.25.rnreg}.
+@item N
+@opindex dN
+Dump after the register move pass, to @file{@var{file}.18.regmove}.
+@item r
+@opindex dr
+Dump after RTL generation, to @file{@var{file}.00.rtl}.
+@item R
+@opindex dR
+Dump after the second scheduling pass, to @file{@var{file}.27.sched2}.
+@item s
+@opindex ds
+Dump after CSE (including the jump optimization that sometimes follows
+CSE), to @file{@var{file}.08.cse}.
+@item S
+@opindex dS
+Dump after the first scheduling pass, to @file{@var{file}.19.sched}.
+@item t
+@opindex dt
+Dump after the second CSE pass (including the jump optimization that
+sometimes follows CSE), to @file{@var{file}.12.cse2}.
+@item w
+@opindex dw
+Dump after the second flow pass, to @file{@var{file}.23.flow2}.
+@item X
+@opindex dX
+Dump after SSA dead code elimination, to @file{@var{file}.06.ssadce}.
+@item z
+@opindex dz
+Dump after the peephole pass, to @file{@var{file}.24.peephole2}.
+@item a
+@opindex da
+Produce all the dumps listed above.
+@item m
+@opindex dm
+Print statistics on memory usage, at the end of the run, to
+standard error.
+@item p
+@opindex dp
+Annotate the assembler output with a comment indicating which
+pattern and alternative was used.  The length of each instruction is
+also printed.
+@item P
+@opindex dP
+Dump the RTL in the assembler output as a comment before each instruction.
+Also turns on @option{-dp} annotation.
+@item v
+@opindex dv
+For each of the other indicated dump files (except for
+@file{@var{file}.00.rtl}), dump a representation of the control flow graph
+suitable for viewing with VCG to @file{@var{file}.@var{pass}.vcg}.
+@item x
+@opindex dx
+Just generate RTL for a function instead of compiling it.  Usually used
+with @samp{r}.
+@item y
+@opindex dy
+Dump debugging information during parsing, to standard error.
+@end table
+
+@item -fdump-unnumbered
+@opindex fdump-unnumbered
+When doing debugging dumps (see @option{-d} option above), suppress instruction
+numbers and line number note output.  This makes it more feasible to
+use diff on debugging dumps for compiler invocations with different
+options, in particular with and without @option{-g}.
+
+@item -fdump-translation-unit @r{(C and C++ only)}
+@itemx -fdump-translation-unit-@var{options} @r{(C and C++ only)}
+@opindex fdump-translation-unit
+Dump a representation of the tree structure for the entire translation
+unit to a file.  The file name is made by appending @file{.tu} to the
+source file name.  If the @samp{-@var{options}} form is used, @var{options}
+controls the details of the dump as described for the
+@option{-fdump-tree} options.
+
+@item -fdump-class-hierarchy @r{(C++ only)}
+@itemx -fdump-class-hierarchy-@var{options} @r{(C++ only)}
+@opindex fdump-class-hierarchy
+Dump a representation of each class's hierarchy and virtual function
+table layout to a file.  The file name is made by appending @file{.class}
+to the source file name.  If the @samp{-@var{options}} form is used,
+@var{options} controls the details of the dump as described for the
+@option{-fdump-tree} options.
+
+@item -fdump-tree-@var{switch} @r{(C++ only)}
+@itemx -fdump-tree-@var{switch}-@var{options} @r{(C++ only)}
+@opindex fdump-tree
+Control the dumping at various stages of processing the intermediate
+language tree to a file.  The file name is generated by appending a switch
+specific suffix to the source file name.  If the @samp{-@var{options}}
+form is used, @var{options} is a list of @samp{-} separated options that
+control the details of the dump. Not all options are applicable to all
+dumps, those which are not meaningful will be ignored. The following
+options are available
+
+@table @samp
+@item address
+Print the address of each node.  Usually this is not meaningful as it
+changes according to the environment and source file. Its primary use
+is for tying up a dump file with a debug environment.
+@item slim
+Inhibit dumping of members of a scope or body of a function merely
+because that scope has been reached. Only dump such items when they
+are directly reachable by some other path.
+@item all
+Turn on all options.
+@end table
+
+The following tree dumps are possible:
+@table @samp
+@item original
+Dump before any tree based optimization, to @file{@var{file}.original}.
+@item optimized
+Dump after all tree based optimization, to @file{@var{file}.optimized}.
+@item inlined
+Dump after function inlining, to @file{@var{file}.inlined}.
+@end table
+
+@item -fpretend-float
+@opindex fpretend-float
+When running a cross-compiler, pretend that the target machine uses the
+same floating point format as the host machine.  This causes incorrect
+output of the actual floating constants, but the actual instruction
+sequence will probably be the same as GCC would make when running on
+the target machine.
+
+@item -save-temps
+@opindex save-temps
+Store the usual ``temporary'' intermediate files permanently; place them
+in the current directory and name them based on the source file.  Thus,
+compiling @file{foo.c} with @samp{-c -save-temps} would produce files
+@file{foo.i} and @file{foo.s}, as well as @file{foo.o}.  This creates a
+preprocessed @file{foo.i} output file even though the compiler now
+normally uses an integrated preprocessor.
+
+@item -time
+@opindex time
+Report the CPU time taken by each subprocess in the compilation
+sequence.  For C source files, this is the compiler proper and assembler
+(plus the linker if linking is done).  The output looks like this:
+
+@smallexample
+# cc1 0.12 0.01
+# as 0.00 0.01
+@end smallexample
+
+The first number on each line is the ``user time,'' that is time spent
+executing the program itself.  The second number is ``system time,''
+time spent executing operating system routines on behalf of the program.
+Both numbers are in seconds.
+
+@item -print-file-name=@var{library}
+@opindex print-file-name
+Print the full absolute name of the library file @var{library} that
+would be used when linking---and don't do anything else.  With this
+option, GCC does not compile or link anything; it just prints the
+file name.
+
+@item -print-multi-directory
+@opindex print-multi-directory
+Print the directory name corresponding to the multilib selected by any
+other switches present in the command line.  This directory is supposed
+to exist in @env{GCC_EXEC_PREFIX}.
+
+@item -print-multi-lib
+@opindex print-multi-lib
+Print the mapping from multilib directory names to compiler switches
+that enable them.  The directory name is separated from the switches by
+@samp{;}, and each switch starts with an @samp{@@} instead of the
+@samp{-}, without spaces between multiple switches.  This is supposed to
+ease shell-processing.
+
+@item -print-prog-name=@var{program}
+@opindex print-prog-name
+Like @option{-print-file-name}, but searches for a program such as @samp{cpp}.
+
+@item -print-libgcc-file-name
+@opindex print-libgcc-file-name
+Same as @option{-print-file-name=libgcc.a}.
+
+This is useful when you use @option{-nostdlib} or @option{-nodefaultlibs}
+but you do want to link with @file{libgcc.a}.  You can do
+
+@example
+gcc -nostdlib @var{files}@dots{} `gcc -print-libgcc-file-name`
+@end example
+
+@item -print-search-dirs
+@opindex print-search-dirs
+Print the name of the configured installation directory and a list of
+program and library directories gcc will search---and don't do anything else.
+
+This is useful when gcc prints the error message
+@samp{installation problem, cannot exec cpp0: No such file or directory}.
+To resolve this you either need to put @file{cpp0} and the other compiler
+components where gcc expects to find them, or you can set the environment
+variable @env{GCC_EXEC_PREFIX} to the directory where you installed them.
+Don't forget the trailing '/'.
+@xref{Environment Variables}.
+
+@item -dumpmachine
+@opindex dumpmachine
+Print the compiler's target machine (for example,
+@samp{i686-pc-linux-gnu})---and don't do anything else.
+
+@item -dumpversion
+@opindex dumpversion
+Print the compiler version (for example, @samp{3.0})---and don't do
+anything else.
+
+@item -dumpspecs
+@opindex dumpspecs
+Print the compiler's built-in specs---and don't do anything else.  (This
+is used when GCC itself is being built.)  @xref{Spec Files}.
+@end table
+
+@node Optimize Options
+@section Options That Control Optimization
+@cindex optimize options
+@cindex options, optimization
+
+These options control various sorts of optimizations:
+
+@table @gcctabopt
+@item -O
+@itemx -O1
+@opindex O
+@opindex O1
+Optimize.  Optimizing compilation takes somewhat more time, and a lot
+more memory for a large function.
+
+Without @option{-O}, the compiler's goal is to reduce the cost of
+compilation and to make debugging produce the expected results.
+Statements are independent: if you stop the program with a breakpoint
+between statements, you can then assign a new value to any variable or
+change the program counter to any other statement in the function and
+get exactly the results you would expect from the source code.
+
+With @option{-O}, the compiler tries to reduce code size and execution
+time, without performing any optimizations that take a great deal of
+compilation time.
+
+@item -O2
+@opindex O2
+Optimize even more.  GCC performs nearly all supported optimizations
+that do not involve a space-speed tradeoff.  The compiler does not
+perform loop unrolling or function inlining when you specify @option{-O2}.
+As compared to @option{-O}, this option increases both compilation time
+and the performance of the generated code.
+
+@option{-O2} turns on all optional optimizations except for loop unrolling,
+function inlining, and register renaming.  It also turns on the
+@option{-fforce-mem} option on all machines and frame pointer elimination
+on machines where doing so does not interfere with debugging.
+
+Please note the warning under @option{-fgcse} about
+invoking @option{-O2} on programs that use computed gotos.
+
+@item -O3
+@opindex O3
+Optimize yet more.  @option{-O3} turns on all optimizations specified by
+@option{-O2} and also turns on the @option{-finline-functions} and
+@option{-frename-registers} options.
+
+@item -O0
+@opindex O0
+Do not optimize.
+
+@item -Os
+@opindex Os
+Optimize for size.  @option{-Os} enables all @option{-O2} optimizations that
+do not typically increase code size.  It also performs further
+optimizations designed to reduce code size.
+
+If you use multiple @option{-O} options, with or without level numbers,
+the last such option is the one that is effective.
+@end table
+
+Options of the form @option{-f@var{flag}} specify machine-independent
+flags.  Most flags have both positive and negative forms; the negative
+form of @option{-ffoo} would be @option{-fno-foo}.  In the table below,
+only one of the forms is listed---the one which is not the default.
+You can figure out the other form by either removing @samp{no-} or
+adding it.
+
+@table @gcctabopt
+@item -ffloat-store
+@opindex ffloat-store
+Do not store floating point variables in registers, and inhibit other
+options that might change whether a floating point value is taken from a
+register or memory.
+
+@cindex floating point precision
+This option prevents undesirable excess precision on machines such as
+the 68000 where the floating registers (of the 68881) keep more
+precision than a @code{double} is supposed to have.  Similarly for the
+x86 architecture.  For most programs, the excess precision does only
+good, but a few programs rely on the precise definition of IEEE floating
+point.  Use @option{-ffloat-store} for such programs, after modifying
+them to store all pertinent intermediate computations into variables.
+
+@item -fno-default-inline
+@opindex fno-default-inline
+Do not make member functions inline by default merely because they are
+defined inside the class scope (C++ only).  Otherwise, when you specify
+@w{@option{-O}}, member functions defined inside class scope are compiled
+inline by default; i.e., you don't need to add @samp{inline} in front of
+the member function name.
+
+@item -fno-defer-pop
+@opindex fno-defer-pop
+Always pop the arguments to each function call as soon as that function
+returns.  For machines which must pop arguments after a function call,
+the compiler normally lets arguments accumulate on the stack for several
+function calls and pops them all at once.
+
+@item -fforce-mem
+@opindex fforce-mem
+Force memory operands to be copied into registers before doing
+arithmetic on them.  This produces better code by making all memory
+references potential common subexpressions.  When they are not common
+subexpressions, instruction combination should eliminate the separate
+register-load.  The @option{-O2} option turns on this option.
+
+@item -fforce-addr
+@opindex fforce-addr
+Force memory address constants to be copied into registers before
+doing arithmetic on them.  This may produce better code just as
+@option{-fforce-mem} may.
+
+@item -fomit-frame-pointer
+@opindex fomit-frame-pointer
+Don't keep the frame pointer in a register for functions that
+don't need one.  This avoids the instructions to save, set up and
+restore frame pointers; it also makes an extra register available
+in many functions.  @strong{It also makes debugging impossible on
+some machines.}
+
+On some machines, such as the VAX, this flag has no effect, because
+the standard calling sequence automatically handles the frame pointer
+and nothing is saved by pretending it doesn't exist.  The
+machine-description macro @code{FRAME_POINTER_REQUIRED} controls
+whether a target machine supports this flag.  @xref{Registers,,Register
+Usage, gccint, GNU Compiler Collection (GCC) Internals}.
+
+@item -foptimize-sibling-calls
+@opindex foptimize-sibling-calls
+Optimize sibling and tail recursive calls.
+
+@item -ftrapv
+@opindex ftrapv
+This option generates traps for signed overflow on addition, subtraction,
+multiplication operations.
+
+@item -fno-inline
+@opindex fno-inline
+Don't pay attention to the @code{inline} keyword.  Normally this option
+is used to keep the compiler from expanding any functions inline.
+Note that if you are not optimizing, no functions can be expanded inline.
+
+@item -finline-functions
+@opindex finline-functions
+Integrate all simple functions into their callers.  The compiler
+heuristically decides which functions are simple enough to be worth
+integrating in this way.
+
+If all calls to a given function are integrated, and the function is
+declared @code{static}, then the function is normally not output as
+assembler code in its own right.
+
+@item -finline-limit=@var{n}
+@opindex finline-limit
+By default, gcc limits the size of functions that can be inlined.  This flag
+allows the control of this limit for functions that are explicitly marked as
+inline (ie marked with the inline keyword or defined within the class
+definition in c++).  @var{n} is the size of functions that can be inlined in
+number of pseudo instructions (not counting parameter handling).  The default
+value of @var{n} is 600.
+Increasing this value can result in more inlined code at
+the cost of compilation time and memory consumption.  Decreasing usually makes
+the compilation faster and less code will be inlined (which presumably
+means slower programs).  This option is particularly useful for programs that
+use inlining heavily such as those based on recursive templates with C++.
+
+@emph{Note:} pseudo instruction represents, in this particular context, an
+abstract measurement of function's size.  In no way, it represents a count
+of assembly instructions and as such its exact meaning might change from one
+release to an another.
+
+@item -fkeep-inline-functions
+@opindex fkeep-inline-functions
+Even if all calls to a given function are integrated, and the function
+is declared @code{static}, nevertheless output a separate run-time
+callable version of the function.  This switch does not affect
+@code{extern inline} functions.
+
+@item -fkeep-static-consts
+@opindex fkeep-static-consts
+Emit variables declared @code{static const} when optimization isn't turned
+on, even if the variables aren't referenced.
+
+GCC enables this option by default.  If you want to force the compiler to
+check if the variable was referenced, regardless of whether or not
+optimization is turned on, use the @option{-fno-keep-static-consts} option.
+
+@item -fmerge-constants
+Attempt to merge identical constants (string constants and floating point
+constants) accross compilation units.
+
+This option is default for optimized compilation if assembler and linker
+support it.  Use @option{-fno-merge-constants} to inhibit this behavior.
+
+@item -fmerge-all-constants
+Attempt to merge identical constants and identical variables.
+
+This option implies @option{-fmerge-constants}.  In addition to
+@option{-fmerge-constants} this considers e.g. even constant initialized
+arrays or initialized constant variables with integral or floating point
+types.  Languages like C or C++ require each non-automatic variable to
+have distinct location, so using this option will result in non-conforming
+behavior.
+
+@item -fno-function-cse
+@opindex fno-function-cse
+Do not put function addresses in registers; make each instruction that
+calls a constant function contain the function's address explicitly.
+
+This option results in less efficient code, but some strange hacks
+that alter the assembler output may be confused by the optimizations
+performed when this option is not used.
+
+@item -ffast-math
+@opindex ffast-math
+Sets @option{-fno-math-errno}, @option{-funsafe-math-optimizations}, and @*
+@option{-fno-trapping-math}.
+
+This option causes the preprocessor macro @code{__FAST_MATH__} to be defined.
+
+This option should never be turned on by any @option{-O} option since
+it can result in incorrect output for programs which depend on
+an exact implementation of IEEE or ISO rules/specifications for
+math functions.
+
+@item -fno-math-errno
+@opindex fno-math-errno
+Do not set ERRNO after calling math functions that are executed
+with a single instruction, e.g., sqrt.  A program that relies on
+IEEE exceptions for math error handling may want to use this flag
+for speed while maintaining IEEE arithmetic compatibility.
+
+This option should never be turned on by any @option{-O} option since
+it can result in incorrect output for programs which depend on
+an exact implementation of IEEE or ISO rules/specifications for
+math functions.
+
+The default is @option{-fmath-errno}.
+
+@item -funsafe-math-optimizations
+@opindex funsafe-math-optimizations
+Allow optimizations for floating-point arithmetic that (a) assume
+that arguments and results are valid and (b) may violate IEEE or
+ANSI standards.  When used at link-time, it may include libraries
+or startup files that change the default FPU control word or other
+similar optimizations.
+
+This option should never be turned on by any @option{-O} option since
+it can result in incorrect output for programs which depend on
+an exact implementation of IEEE or ISO rules/specifications for
+math functions.
+
+The default is @option{-fno-unsafe-math-optimizations}.
+
+@item -fno-trapping-math
+@opindex fno-trapping-math
+Compile code assuming that floating-point operations cannot generate
+user-visible traps.  Setting this option may allow faster code
+if one relies on ``non-stop'' IEEE arithmetic, for example.
+
+This option should never be turned on by any @option{-O} option since
+it can result in incorrect output for programs which depend on
+an exact implementation of IEEE or ISO rules/specifications for
+math functions.
+
+The default is @option{-ftrapping-math}.
+@end table
+
+The following options control specific optimizations.  The @option{-O2}
+option turns on all of these optimizations except @option{-funroll-loops}
+and @option{-funroll-all-loops}.  On most machines, the @option{-O} option
+turns on the @option{-fthread-jumps} and @option{-fdelayed-branch} options,
+but specific machines may handle it differently.
+
+You can use the following flags in the rare cases when ``fine-tuning''
+of optimizations to be performed is desired.
+
+Not all of the optimizations performed by GCC have @option{-f} options
+to control them.
+
+@table @gcctabopt
+@item -fstrength-reduce
+@opindex fstrength-reduce
+Perform the optimizations of loop strength reduction and
+elimination of iteration variables.
+
+@item -fthread-jumps
+@opindex fthread-jumps
+Perform optimizations where we check to see if a jump branches to a
+location where another comparison subsumed by the first is found.  If
+so, the first branch is redirected to either the destination of the
+second branch or a point immediately following it, depending on whether
+the condition is known to be true or false.
+
+@item -fcse-follow-jumps
+@opindex fcse-follow-jumps
+In common subexpression elimination, scan through jump instructions
+when the target of the jump is not reached by any other path.  For
+example, when CSE encounters an @code{if} statement with an
+@code{else} clause, CSE will follow the jump when the condition
+tested is false.
+
+@item -fcse-skip-blocks
+@opindex fcse-skip-blocks
+This is similar to @option{-fcse-follow-jumps}, but causes CSE to
+follow jumps which conditionally skip over blocks.  When CSE
+encounters a simple @code{if} statement with no else clause,
+@option{-fcse-skip-blocks} causes CSE to follow the jump around the
+body of the @code{if}.
+
+@item -frerun-cse-after-loop
+@opindex frerun-cse-after-loop
+Re-run common subexpression elimination after loop optimizations has been
+performed.
+
+@item -frerun-loop-opt
+@opindex frerun-loop-opt
+Run the loop optimizer twice.
+
+@item -fgcse
+@opindex fgcse
+Perform a global common subexpression elimination pass.
+This pass also performs global constant and copy propagation.
+
+@emph{Note:} When compiling a program using computed gotos, a GCC
+extension, you may get better runtime performance if you disable
+the global common subexpression elmination pass by adding
+@option{-fno-gcse} to the command line.
+
+@item -fgcse-lm
+@opindex fgcse-lm
+When @option{-fgcse-lm} is enabled, global common subexpression elimination will
+attempt to move loads which are only killed by stores into themselves.  This
+allows a loop containing a load/store sequence to be changed to a load outside
+the loop, and a copy/store within the loop.
+
+@item -fgcse-sm
+@opindex fgcse-sm
+When @option{-fgcse-sm} is enabled, A store motion pass is run after global common
+subexpression elimination.  This pass will attempt to move stores out of loops.
+When used in conjunction with @option{-fgcse-lm}, loops containing a load/store sequence
+can be changed to a load before the loop and a store after the loop.
+
+@item -fdelete-null-pointer-checks
+@opindex fdelete-null-pointer-checks
+Use global dataflow analysis to identify and eliminate useless checks
+for null pointers.  The compiler assumes that dereferencing a null
+pointer would have halted the program.  If a pointer is checked after
+it has already been dereferenced, it cannot be null.
+
+In some environments, this assumption is not true, and programs can
+safely dereference null pointers.  Use
+@option{-fno-delete-null-pointer-checks} to disable this optimization
+for programs which depend on that behavior.
+
+@item -fexpensive-optimizations
+@opindex fexpensive-optimizations
+Perform a number of minor optimizations that are relatively expensive.
+
+@item -foptimize-register-move
+@itemx -fregmove
+@opindex foptimize-register-move
+@opindex fregmove
+Attempt to reassign register numbers in move instructions and as
+operands of other simple instructions in order to maximize the amount of
+register tying.  This is especially helpful on machines with two-operand
+instructions.  GCC enables this optimization by default with @option{-O2}
+or higher.
+
+Note @option{-fregmove} and @option{-foptimize-register-move} are the same
+optimization.
+
+@item -fdelayed-branch
+@opindex fdelayed-branch
+If supported for the target machine, attempt to reorder instructions
+to exploit instruction slots available after delayed branch
+instructions.
+
+@item -fschedule-insns
+@opindex fschedule-insns
+If supported for the target machine, attempt to reorder instructions to
+eliminate execution stalls due to required data being unavailable.  This
+helps machines that have slow floating point or memory load instructions
+by allowing other instructions to be issued until the result of the load
+or floating point instruction is required.
+
+@item -fschedule-insns2
+@opindex fschedule-insns2
+Similar to @option{-fschedule-insns}, but requests an additional pass of
+instruction scheduling after register allocation has been done.  This is
+especially useful on machines with a relatively small number of
+registers and where memory load instructions take more than one cycle.
+
+@item -ffunction-sections
+@itemx -fdata-sections
+@opindex ffunction-sections
+@opindex fdata-sections
+Place each function or data item into its own section in the output
+file if the target supports arbitrary sections.  The name of the
+function or the name of the data item determines the section's name
+in the output file.
+
+Use these options on systems where the linker can perform optimizations
+to improve locality of reference in the instruction space.  HPPA
+processors running HP-UX and Sparc processors running Solaris 2 have
+linkers with such optimizations.  Other systems using the ELF object format
+as well as AIX may have these optimizations in the future.
+
+Only use these options when there are significant benefits from doing
+so.  When you specify these options, the assembler and linker will
+create larger object and executable files and will also be slower.
+You will not be able to use @code{gprof} on all systems if you
+specify this option and you may have problems with debugging if
+you specify both this option and @option{-g}.
+
+@item -fcaller-saves
+@opindex fcaller-saves
+Enable values to be allocated in registers that will be clobbered by
+function calls, by emitting extra instructions to save and restore the
+registers around such calls.  Such allocation is done only when it
+seems to result in better code than would otherwise be produced.
+
+This option is always enabled by default on certain machines, usually
+those which have no call-preserved registers to use instead.
+
+For all machines, optimization level 2 and higher enables this flag by
+default.
+
+@item -funroll-loops
+@opindex funroll-loops
+Unroll loops whose number of iterations can be determined at compile
+time or upon entry to the loop.  @option{-funroll-loops} implies both
+@option{-fstrength-reduce} and @option{-frerun-cse-after-loop}.  This
+option makes code larger, and may or may not make it run faster.
+
+@item -funroll-all-loops
+@opindex funroll-all-loops
+Unroll all loops, even if their number of iterations is uncertain when
+the loop is entered.  This usually makes programs run more slowly.
+@option{-funroll-all-loops} implies the same options as
+@option{-funroll-loops},
+
+@item -fprefetch-loop-arrays
+@opindex fprefetch-loop-arrays
+If supported by the target machine, generate instructions to prefetch
+memory to improve the performance of loops that access large arrays.
+
+@item -fmove-all-movables
+@opindex fmove-all-movables
+Forces all invariant computations in loops to be moved
+outside the loop.
+
+@item -freduce-all-givs
+@opindex freduce-all-givs
+Forces all general-induction variables in loops to be
+strength-reduced.
+
+@emph{Note:} When compiling programs written in Fortran,
+@option{-fmove-all-movables} and @option{-freduce-all-givs} are enabled
+by default when you use the optimizer.
+
+These options may generate better or worse code; results are highly
+dependent on the structure of loops within the source code.
+
+These two options are intended to be removed someday, once
+they have helped determine the efficacy of various
+approaches to improving loop optimizations.
+
+Please let us (@w{@email{gcc@@gcc.gnu.org}} and @w{@email{fortran@@gnu.org}})
+know how use of these options affects
+the performance of your production code.
+We're very interested in code that runs @emph{slower}
+when these options are @emph{enabled}.
+
+@item -fno-peephole
+@itemx -fno-peephole2
+@opindex fno-peephole
+@opindex fno-peephole2
+Disable any machine-specific peephole optimizations.  The difference
+between @option{-fno-peephole} and @option{-fno-peephole2} is in how they
+are implemented in the compiler; some targets use one, some use the
+other, a few use both.
+
+@item -fbranch-probabilities
+@opindex fbranch-probabilities
+After running a program compiled with @option{-fprofile-arcs}
+(@pxref{Debugging Options,, Options for Debugging Your Program or
+@command{gcc}}), you can compile it a second time using
+@option{-fbranch-probabilities}, to improve optimizations based on
+the number of times each branch was taken.  When the program
+compiled with @option{-fprofile-arcs} exits it saves arc execution
+counts to a file called @file{@var{sourcename}.da} for each source
+file  The information in this data file is very dependent on the
+structure of the generated code, so you must use the same source code
+and the same optimization options for both compilations.
+
+With @option{-fbranch-probabilities}, GCC puts a @samp{REG_EXEC_COUNT}
+note on the first instruction of each basic block, and a
+@samp{REG_BR_PROB} note on each @samp{JUMP_INSN} and @samp{CALL_INSN}.
+These can be used to improve optimization.  Currently, they are only
+used in one place: in @file{reorg.c}, instead of guessing which path a
+branch is mostly to take, the @samp{REG_BR_PROB} values are used to
+exactly determine which path is taken more often.
+
+@item -fno-guess-branch-probability
+@opindex fno-guess-branch-probability
+Do not guess branch probabilities using a randomized model.
+
+Sometimes gcc will opt to use a randomized model to guess branch
+probabilities, when none are available from either profiling feedback
+(@option{-fprofile-arcs}) or @samp{__builtin_expect}.  This means that
+different runs of the compiler on the same program may produce different
+object code.
+
+In a hard real-time system, people don't want different runs of the
+compiler to produce code that has different behavior; minimizing
+non-determinism is of paramount import.  This switch allows users to
+reduce non-determinism, possibly at the expense of inferior
+optimization.
+
+@item -fstrict-aliasing
+@opindex fstrict-aliasing
+Allows the compiler to assume the strictest aliasing rules applicable to
+the language being compiled.  For C (and C++), this activates
+optimizations based on the type of expressions.  In particular, an
+object of one type is assumed never to reside at the same address as an
+object of a different type, unless the types are almost the same.  For
+example, an @code{unsigned int} can alias an @code{int}, but not a
+@code{void*} or a @code{double}.  A character type may alias any other
+type.
+
+Pay special attention to code like this:
+@example
+union a_union @{
+  int i;
+  double d;
+@};
+
+int f() @{
+  a_union t;
+  t.d = 3.0;
+  return t.i;
+@}
+@end example
+The practice of reading from a different union member than the one most
+recently written to (called ``type-punning'') is common.  Even with
+@option{-fstrict-aliasing}, type-punning is allowed, provided the memory
+is accessed through the union type.  So, the code above will work as
+expected.  However, this code might not:
+@example
+int f() @{
+  a_union t;
+  int* ip;
+  t.d = 3.0;
+  ip = &t.i;
+  return *ip;
+@}
+@end example
+
+Every language that wishes to perform language-specific alias analysis
+should define a function that computes, given an @code{tree}
+node, an alias set for the node.  Nodes in different alias sets are not
+allowed to alias.  For an example, see the C front-end function
+@code{c_get_alias_set}.
+
+@item -falign-functions
+@itemx -falign-functions=@var{n}
+@opindex falign-functions
+Align the start of functions to the next power-of-two greater than
+@var{n}, skipping up to @var{n} bytes.  For instance,
+@option{-falign-functions=32} aligns functions to the next 32-byte
+boundary, but @option{-falign-functions=24} would align to the next
+32-byte boundary only if this can be done by skipping 23 bytes or less.
+
+@option{-fno-align-functions} and @option{-falign-functions=1} are
+equivalent and mean that functions will not be aligned.
+
+Some assemblers only support this flag when @var{n} is a power of two;
+in that case, it is rounded up.
+
+If @var{n} is not specified, use a machine-dependent default.
+
+@item -falign-labels
+@itemx -falign-labels=@var{n}
+@opindex falign-labels
+Align all branch targets to a power-of-two boundary, skipping up to
+@var{n} bytes like @option{-falign-functions}.  This option can easily
+make code slower, because it must insert dummy operations for when the
+branch target is reached in the usual flow of the code.
+
+If @option{-falign-loops} or @option{-falign-jumps} are applicable and
+are greater than this value, then their values are used instead.
+
+If @var{n} is not specified, use a machine-dependent default which is
+very likely to be @samp{1}, meaning no alignment.
+
+@item -falign-loops
+@itemx -falign-loops=@var{n}
+@opindex falign-loops
+Align loops to a power-of-two boundary, skipping up to @var{n} bytes
+like @option{-falign-functions}.  The hope is that the loop will be
+executed many times, which will make up for any execution of the dummy
+operations.
+
+If @var{n} is not specified, use a machine-dependent default.
+
+@item -falign-jumps
+@itemx -falign-jumps=@var{n}
+@opindex falign-jumps
+Align branch targets to a power-of-two boundary, for branch targets
+where the targets can only be reached by jumping, skipping up to @var{n}
+bytes like @option{-falign-functions}.  In this case, no dummy operations
+need be executed.
+
+If @var{n} is not specified, use a machine-dependent default.
+
+@item -fssa
+@opindex fssa
+Perform optimizations in static single assignment form.  Each function's
+flow graph is translated into SSA form, optimizations are performed, and
+the flow graph is translated back from SSA form.  Users should not
+specify this option, since it is not yet ready for production use.
+
+@item -fssa-ccp
+@opindex fssa-ccp
+Perform Sparse Conditional Constant Propagation in SSA form.  Requires
+@option{-fssa}.  Like @option{-fssa}, this is an experimental feature.
+
+@item -fssa-dce
+@opindex fssa-dce
+Perform aggressive dead-code elimination in SSA form.  Requires @option{-fssa}.
+Like @option{-fssa}, this is an experimental feature.
+
+@item -fsingle-precision-constant
+@opindex fsingle-precision-constant
+Treat floating point constant as single precision constant instead of
+implicitly converting it to double precision constant.
+
+@item -frename-registers
+@opindex frename-registers
+Attempt to avoid false dependencies in scheduled code by making use
+of registers left over after register allocation.  This optimization
+will most benefit processors with lots of registers.  It can, however,
+make debugging impossible, since variables will no longer stay in
+a ``home register''.
+
+@item -fno-cprop-registers
+@opindex fno-cprop-registers
+After register allocation and post-register allocation instruction splitting,
+we perform a copy-propagation pass to try to reduce scheduling dependencies
+and occasionally eliminate the copy.
+
+@item --param @var{name}=@var{value}
+@opindex param
+In some places, GCC uses various constants to control the amount of
+optimization that is done.  For example, GCC will not inline functions
+that contain more that a certain number of instructions.  You can
+control some of these constants on the command-line using the
+@option{--param} option.
+
+In each case, the @var{value} is an integer.  The allowable choices for
+@var{name} are given in the following table:
+
+@table @gcctabopt
+@item max-delay-slot-insn-search
+The maximum number of instructions to consider when looking for an
+instruction to fill a delay slot.  If more than this arbitrary number of
+instructions is searched, the time savings from filling the delay slot
+will be minimal so stop searching.  Increasing values mean more
+aggressive optimization, making the compile time increase with probably
+small improvement in executable run time.
+
+@item max-delay-slot-live-search
+When trying to fill delay slots, the maximum number of instructions to
+consider when searching for a block with valid live register
+information.  Increasing this arbitrarily chosen value means more
+aggressive optimization, increasing the compile time.  This parameter
+should be removed when the delay slot code is rewritten to maintain the
+control-flow graph.
+
+@item max-gcse-memory
+The approximate maximum amount of memory that will be allocated in
+order to perform the global common subexpression elimination
+optimization.  If more memory than specified is required, the
+optimization will not be done.
+
+@item max-gcse-passes
+The maximum number of passes of GCSE to run.
+
+@item max-pending-list-length
+The maximum number of pending dependencies scheduling will allow
+before flushing the current state and starting over.  Large functions
+with few branches or calls can create excessively large lists which
+needlessly consume memory and resources.
+
+@item max-inline-insns
+If an function contains more than this many instructions, it
+will not be inlined.  This option is precisely equivalent to
+@option{-finline-limit}.
+
+@end table
+@end table
+
+@node Preprocessor Options
+@section Options Controlling the Preprocessor
+@cindex preprocessor options
+@cindex options, preprocessor
+
+These options control the C preprocessor, which is run on each C source
+file before actual compilation.
+
+If you use the @option{-E} option, nothing is done except preprocessing.
+Some of these options make sense only together with @option{-E} because
+they cause the preprocessor output to be unsuitable for actual
+compilation.
+
+@table @gcctabopt
+@item -include @var{file}
+@opindex include
+Process @var{file} as input before processing the regular input file.
+In effect, the contents of @var{file} are compiled first.  Any @option{-D}
+and @option{-U} options on the command line are always processed before
+@option{-include @var{file}}, regardless of the order in which they are
+written.  All the @option{-include} and @option{-imacros} options are
+processed in the order in which they are written.
+
+@item -imacros @var{file}
+@opindex imacros
+Process @var{file} as input, discarding the resulting output, before
+processing the regular input file.  Because the output generated from
+@var{file} is discarded, the only effect of @option{-imacros @var{file}}
+is to make the macros defined in @var{file} available for use in the
+main input.  All the @option{-include} and @option{-imacros} options are
+processed in the order in which they are written.
+
+@item -idirafter @var{dir}
+@opindex idirafter
+@cindex second include path
+Add the directory @var{dir} to the second include path.  The directories
+on the second include path are searched when a header file is not found
+in any of the directories in the main include path (the one that
+@option{-I} adds to).
+
+@item -iprefix @var{prefix}
+@opindex iprefix
+Specify @var{prefix} as the prefix for subsequent @option{-iwithprefix}
+options.
+
+@item -iwithprefix @var{dir}
+@opindex iwithprefix
+Add a directory to the second include path.  The directory's name is
+made by concatenating @var{prefix} and @var{dir}, where @var{prefix} was
+specified previously with @option{-iprefix}.  If you have not specified a
+prefix yet, the directory containing the installed passes of the
+compiler is used as the default.
+
+@item -iwithprefixbefore @var{dir}
+@opindex iwithprefixbefore
+Add a directory to the main include path.  The directory's name is made
+by concatenating @var{prefix} and @var{dir}, as in the case of
+@option{-iwithprefix}.
+
+@item -isystem @var{dir}
+@opindex isystem
+Add a directory to the beginning of the second include path, marking it
+as a system directory, so that it gets the same special treatment as
+is applied to the standard system directories.
+
+@item -nostdinc
+@opindex nostdinc
+Do not search the standard system directories for header files.  Only
+the directories you have specified with @option{-I} options (and the
+current directory, if appropriate) are searched.  @xref{Directory
+Options}, for information on @option{-I}.
+
+By using both @option{-nostdinc} and @option{-I-}, you can limit the include-file
+search path to only those directories you specify explicitly.
+
+@item -remap
+@opindex remap
+When searching for a header file in a directory, remap file names if a
+file named @file{header.gcc} exists in that directory.  This can be used
+to work around limitations of file systems with file name restrictions.
+The @file{header.gcc} file should contain a series of lines with two
+tokens on each line: the first token is the name to map, and the second
+token is the actual name to use.
+
+@item -undef
+@opindex undef
+Do not predefine any nonstandard macros.  (Including architecture flags).
+
+@item -E
+@opindex E
+Run only the C preprocessor.  Preprocess all the C source files
+specified and output the results to standard output or to the
+specified output file.
+
+@item -C
+@opindex C
+Tell the preprocessor not to discard comments.  Used with the
+@option{-E} option.
+
+@item -P
+@opindex P
+Tell the preprocessor not to generate @samp{#line} directives.
+Used with the @option{-E} option.
+
+@cindex make
+@cindex dependencies, make
+@item -M
+@opindex M
+Instead of outputting the result of preprocessing, output a rule
+suitable for @code{make} describing the dependencies of the main source
+file.  The preprocessor outputs one @code{make} rule containing the
+object file name for that source file, a colon, and the names of all the
+included files.  Unless overridden explicitly, the object file name
+consists of the basename of the source file with any suffix replaced with
+object file suffix.  If there are many included files then the
+rule is split into several lines using @samp{\}-newline.
+
+@option{-M} implies @option{-E}.
+
+@item -MM
+@opindex MM
+Like @option{-M}, but mention only the files included with @samp{#include
+"@var{file}"}.  System header files included with @samp{#include
+<@var{file}>} are omitted.
+
+@item -MD
+@opindex MD
+Like @option{-M} but the dependency information is written to a file
+rather than stdout.  @code{gcc} will use the same file name and
+directory as the object file, but with the suffix @file{.d} instead.
+
+This is in addition to compiling the main file as specified---@option{-MD}
+does not inhibit ordinary compilation the way @option{-M} does,
+unless you also specify @option{-MG}.
+
+With Mach, you can use the utility @code{md} to merge multiple
+dependency files into a single dependency file suitable for using with
+the @samp{make} command.
+
+@item -MMD
+@opindex MMD
+Like @option{-MD} except mention only user header files, not system
+-header files.
+
+@item -MF @var{file}
+@opindex MF
+When used with @option{-M} or @option{-MM}, specifies a file to write the
+dependencies to.  This allows the preprocessor to write the preprocessed
+file to stdout normally.  If no @option{-MF} switch is given, CPP sends
+the rules to stdout and suppresses normal preprocessed output.
+
+Another way to specify output of a @code{make} rule is by setting
+the environment variable @env{DEPENDENCIES_OUTPUT} (@pxref{Environment
+Variables}).
+
+@item -MG
+@opindex MG
+When used with @option{-M} or @option{-MM}, @option{-MG} says to treat missing
+header files as generated files and assume they live in the same
+directory as the source file.  It suppresses preprocessed output, as a
+missing header file is ordinarily an error.
+
+This feature is used in automatic updating of makefiles.
+
+@item -MP
+@opindex MP
+This option instructs CPP to add a phony target for each dependency
+other than the main file, causing each to depend on nothing.  These
+dummy rules work around errors @code{make} gives if you remove header
+files without updating the @code{Makefile} to match.
+
+This is typical output:-
+
+@smallexample
+/tmp/test.o: /tmp/test.c /tmp/test.h
+
+/tmp/test.h:
+@end smallexample
+
+@item -MQ @var{target}
+@item -MT @var{target}
+@opindex MQ
+@opindex MT
+By default CPP uses the main file name, including any path, and appends
+the object suffix, normally ``.o'', to it to obtain the name of the
+target for dependency generation.  With @option{-MT} you can specify a
+target yourself, overriding the default one.
+
+If you want multiple targets, you can specify them as a single argument
+to @option{-MT}, or use multiple @option{-MT} options.
+
+The targets you specify are output in the order they appear on the
+command line.  @option{-MQ} is identical to @option{-MT}, except that the
+target name is quoted for Make, but with @option{-MT} it isn't.  For
+example, @option{-MT '$(objpfx)foo.o'} gives
+
+@smallexample
+$(objpfx)foo.o: /tmp/foo.c
+@end smallexample
+
+but @option{-MQ '$(objpfx)foo.o'} gives
+
+@smallexample
+$$(objpfx)foo.o: /tmp/foo.c
+@end smallexample
+
+The default target is automatically quoted, as if it were given with
+@option{-MQ}.
+
+@item -H
+@opindex H
+Print the name of each header file used, in addition to other normal
+activities.
+
+@item -A@var{question}(@var{answer})
+@opindex A
+Assert the answer @var{answer} for @var{question}, in case it is tested
+with a preprocessing conditional such as @samp{#if
+#@var{question}(@var{answer})}.  @option{-A-} disables the standard
+assertions that normally describe the target machine.
+
+@item -D@var{macro}
+@opindex D
+Define macro @var{macro} with the string @samp{1} as its definition.
+
+@item -D@var{macro}=@var{defn}
+Define macro @var{macro} as @var{defn}.  All instances of @option{-D} on
+the command line are processed before any @option{-U} options.
+
+Any @option{-D} and @option{-U} options on the command line are processed in
+order, and always before @option{-imacros @var{file}}, regardless of the
+order in which they are written.
+
+@item -U@var{macro}
+@opindex U
+Undefine macro @var{macro}.  @option{-U} options are evaluated after all
+@option{-D} options, but before any @option{-include} and @option{-imacros}
+options.
+
+Any @option{-D} and @option{-U} options on the command line are processed in
+order, and always before @option{-imacros @var{file}}, regardless of the
+order in which they are written.
+
+@item -dM
+@opindex dM
+Tell the preprocessor to output only a list of the macro definitions
+that are in effect at the end of preprocessing.  Used with the @option{-E}
+option.
+
+@item -dD
+@opindex dD
+Tell the preprocessing to pass all macro definitions into the output, in
+their proper sequence in the rest of the output.
+
+@item -dN
+@opindex dN
+Like @option{-dD} except that the macro arguments and contents are omitted.
+Only @samp{#define @var{name}} is included in the output.
+
+@item -dI
+@opindex dI
+Output @samp{#include} directives in addition to the result of
+preprocessing.
+
+@item -fpreprocessed
+@opindex fpreprocessed
+Indicate to the preprocessor that the input file has already been
+preprocessed.  This suppresses things like macro expansion, trigraph
+conversion, escaped newline splicing, and processing of most directives.
+The preprocessor still recognizes and removes comments, so that you can
+pass a file preprocessed with @option{-C} to the compiler without
+problems.  In this mode the integrated preprocessor is little more than
+a tokenizer for the front ends.
+
+@option{-fpreprocessed} is implicit if the input file has one of the
+extensions @samp{i}, @samp{ii} or @samp{mi}.  These are the extensions
+that GCC uses for preprocessed files created by @option{-save-temps}.
+
+@item -trigraphs
+@opindex trigraphs
+Process ISO standard trigraph sequences.  These are three-character
+sequences, all starting with @samp{??}, that are defined by ISO C to
+stand for single characters.  For example, @samp{??/} stands for
+@samp{\}, so @samp{'??/n'} is a character constant for a newline.  By
+default, GCC ignores trigraphs, but in standard-conforming modes it
+converts them.  See the @option{-std} and @option{-ansi} options.
+
+The nine trigraph sequences are
+@table @samp
+@item ??(
+@expansion{} @samp{[}
+
+@item ??)
+@expansion{} @samp{]}
+
+@item ??<
+@expansion{} @samp{@{}
+
+@item ??>
+@expansion{} @samp{@}}
+
+@item ??=
+@expansion{} @samp{#}
+
+@item ??/
+@expansion{} @samp{\}
+
+@item ??'
+@expansion{} @samp{^}
+
+@item ??!
+@expansion{} @samp{|}
+
+@item ??-
+@expansion{} @samp{~}
+
+@end table
+
+Trigraph support is not popular, so many compilers do not implement it
+properly.  Portable code should not rely on trigraphs being either
+converted or ignored.
+
+@item -Wp,@var{option}
+@opindex Wp
+Pass @var{option} as an option to the preprocessor.  If @var{option}
+contains commas, it is split into multiple options at the commas.
+@end table
+
+@node Assembler Options
+@section Passing Options to the Assembler
+
+@c prevent bad page break with this line
+You can pass options to the assembler.
+
+@table @gcctabopt
+@item -Wa,@var{option}
+@opindex Wa
+Pass @var{option} as an option to the assembler.  If @var{option}
+contains commas, it is split into multiple options at the commas.
+@end table
+
+@node Link Options
+@section Options for Linking
+@cindex link options
+@cindex options, linking
+
+These options come into play when the compiler links object files into
+an executable output file.  They are meaningless if the compiler is
+not doing a link step.
+
+@table @gcctabopt
+@cindex file names
+@item @var{object-file-name}
+A file name that does not end in a special recognized suffix is
+considered to name an object file or library.  (Object files are
+distinguished from libraries by the linker according to the file
+contents.)  If linking is done, these object files are used as input
+to the linker.
+
+@item -c
+@itemx -S
+@itemx -E
+@opindex c
+@opindex S
+@opindex E
+If any of these options is used, then the linker is not run, and
+object file names should not be used as arguments.  @xref{Overall
+Options}.
+
+@cindex Libraries
+@item -l@var{library}
+@itemx -l @var{library}
+@opindex l
+Search the library named @var{library} when linking.  (The second
+alternative with the library as a separate argument is only for
+POSIX compliance and is not recommended.)
+
+It makes a difference where in the command you write this option; the
+linker searches and processes libraries and object files in the order they
+are specified.  Thus, @samp{foo.o -lz bar.o} searches library @samp{z}
+after file @file{foo.o} but before @file{bar.o}.  If @file{bar.o} refers
+to functions in @samp{z}, those functions may not be loaded.
+
+The linker searches a standard list of directories for the library,
+which is actually a file named @file{lib@var{library}.a}.  The linker
+then uses this file as if it had been specified precisely by name.
+
+The directories searched include several standard system directories
+plus any that you specify with @option{-L}.
+
+Normally the files found this way are library files---archive files
+whose members are object files.  The linker handles an archive file by
+scanning through it for members which define symbols that have so far
+been referenced but not defined.  But if the file that is found is an
+ordinary object file, it is linked in the usual fashion.  The only
+difference between using an @option{-l} option and specifying a file name
+is that @option{-l} surrounds @var{library} with @samp{lib} and @samp{.a}
+and searches several directories.
+
+@item -lobjc
+@opindex lobjc
+You need this special case of the @option{-l} option in order to
+link an Objective-C program.
+
+@item -nostartfiles
+@opindex nostartfiles
+Do not use the standard system startup files when linking.
+The standard system libraries are used normally, unless @option{-nostdlib}
+or @option{-nodefaultlibs} is used.
+
+@item -nodefaultlibs
+@opindex nodefaultlibs
+Do not use the standard system libraries when linking.
+Only the libraries you specify will be passed to the linker.
+The standard startup files are used normally, unless @option{-nostartfiles}
+is used.  The compiler may generate calls to memcmp, memset, and memcpy
+for System V (and ISO C) environments or to bcopy and bzero for
+BSD environments.  These entries are usually resolved by entries in
+libc.  These entry points should be supplied through some other
+mechanism when this option is specified.
+
+@item -nostdlib
+@opindex nostdlib
+Do not use the standard system startup files or libraries when linking.
+No startup files and only the libraries you specify will be passed to
+the linker.  The compiler may generate calls to memcmp, memset, and memcpy
+for System V (and ISO C) environments or to bcopy and bzero for
+BSD environments.  These entries are usually resolved by entries in
+libc.  These entry points should be supplied through some other
+mechanism when this option is specified.
+
+@cindex @option{-lgcc}, use with @option{-nostdlib}
+@cindex @option{-nostdlib} and unresolved references
+@cindex unresolved references and @option{-nostdlib}
+@cindex @option{-lgcc}, use with @option{-nodefaultlibs}
+@cindex @option{-nodefaultlibs} and unresolved references
+@cindex unresolved references and @option{-nodefaultlibs}
+One of the standard libraries bypassed by @option{-nostdlib} and
+@option{-nodefaultlibs} is @file{libgcc.a}, a library of internal subroutines
+that GCC uses to overcome shortcomings of particular machines, or special
+needs for some languages.
+(@xref{Interface,,Interfacing to GCC Output,gccint,GNU Compiler
+Collection (GCC) Internals},
+for more discussion of @file{libgcc.a}.)
+In most cases, you need @file{libgcc.a} even when you want to avoid
+other standard libraries.  In other words, when you specify @option{-nostdlib}
+or @option{-nodefaultlibs} you should usually specify @option{-lgcc} as well.
+This ensures that you have no unresolved references to internal GCC
+library subroutines.  (For example, @samp{__main}, used to ensure C++
+constructors will be called; @pxref{Collect2,,@code{collect2}, gccint,
+GNU Compiler Collection (GCC) Internals}.)
+
+@item -s
+@opindex s
+Remove all symbol table and relocation information from the executable.
+
+@item -static
+@opindex static
+On systems that support dynamic linking, this prevents linking with the shared
+libraries.  On other systems, this option has no effect.
+
+@item -shared
+@opindex shared
+Produce a shared object which can then be linked with other objects to
+form an executable.  Not all systems support this option.  For predictable
+results, you must also specify the same set of options that were used to
+generate code (@option{-fpic}, @option{-fPIC}, or model suboptions)
+when you specify this option.@footnote{On some systems, @samp{gcc -shared}
+needs to build supplementary stub code for constructors to work.  On
+multi-libbed systems, @samp{gcc -shared} must select the correct support
+libraries to link against.  Failing to supply the correct flags may lead
+to subtle defects.  Supplying them in cases where they are not necessary
+is innocuous.}
+
+@item -shared-libgcc
+@itemx -static-libgcc
+@opindex shared-libgcc
+@opindex static-libgcc
+On systems that provide @file{libgcc} as a shared library, these options
+force the use of either the shared or static version respectively.
+If no shared version of @file{libgcc} was built when the compiler was
+configured, these options have no effect.
+
+There are several situations in which an application should use the
+shared @file{libgcc} instead of the static version.  The most common
+of these is when the application wishes to throw and catch exceptions
+across different shared libraries.  In that case, each of the libraries
+as well as the application itself should use the shared @file{libgcc}.
+
+Therefore, whenever you specify the @option{-shared} option, the GCC
+driver automatically adds @option{-shared-libgcc}, unless you explicitly
+specify @option{-static-libgcc}.  The G++ driver automatically adds
+@option{-shared-libgcc} when you build a main executable as well because
+for C++ programs that is typically the right thing to do.
+(Exception-handling will not work reliably otherwise.)
+
+However, when linking a main executable written in C, you must
+explicitly say @option{-shared-libgcc} if you want to use the shared
+@file{libgcc}.
+
+@item -symbolic
+@opindex symbolic
+Bind references to global symbols when building a shared object.  Warn
+about any unresolved references (unless overridden by the link editor
+option @samp{-Xlinker -z -Xlinker defs}).  Only a few systems support
+this option.
+
+@item -Xlinker @var{option}
+@opindex Xlinker
+Pass @var{option} as an option to the linker.  You can use this to
+supply system-specific linker options which GCC does not know how to
+recognize.
+
+If you want to pass an option that takes an argument, you must use
+@option{-Xlinker} twice, once for the option and once for the argument.
+For example, to pass @option{-assert definitions}, you must write
+@samp{-Xlinker -assert -Xlinker definitions}.  It does not work to write
+@option{-Xlinker "-assert definitions"}, because this passes the entire
+string as a single argument, which is not what the linker expects.
+
+@item -Wl,@var{option}
+@opindex Wl
+Pass @var{option} as an option to the linker.  If @var{option} contains
+commas, it is split into multiple options at the commas.
+
+@item -u @var{symbol}
+@opindex u
+Pretend the symbol @var{symbol} is undefined, to force linking of
+library modules to define it.  You can use @option{-u} multiple times with
+different symbols to force loading of additional library modules.
+@end table
+
+@node Directory Options
+@section Options for Directory Search
+@cindex directory options
+@cindex options, directory search
+@cindex search path
+
+These options specify directories to search for header files, for
+libraries and for parts of the compiler:
+
+@table @gcctabopt
+@item -I@var{dir}
+@opindex I
+Add the directory @var{dir} to the head of the list of directories to be
+searched for header files.  This can be used to override a system header
+file, substituting your own version, since these directories are
+searched before the system header file directories.  However, you should
+not use this option to add directories that contain vendor-supplied
+system header files (use @option{-isystem} for that).  If you use more than
+one @option{-I} option, the directories are scanned in left-to-right
+order; the standard system directories come after.
+
+If a standard system include directory, or a directory specified with
+@option{-isystem}, is also specified with @option{-I}, it will be
+searched only in the position requested by @option{-I}.  Also, it will
+not be considered a system include directory.  If that directory really
+does contain system headers, there is a good chance that they will
+break.  For instance, if GCC's installation procedure edited the headers
+in @file{/usr/include} to fix bugs, @samp{-I/usr/include} will cause the
+original, buggy headers to be found instead of the corrected ones.  GCC
+will issue a warning when a system include directory is hidden in this
+way.
+
+@item -I-
+@opindex I-
+Any directories you specify with @option{-I} options before the @option{-I-}
+option are searched only for the case of @samp{#include "@var{file}"};
+they are not searched for @samp{#include <@var{file}>}.
+
+If additional directories are specified with @option{-I} options after
+the @option{-I-}, these directories are searched for all @samp{#include}
+directives.  (Ordinarily @emph{all} @option{-I} directories are used
+this way.)
+
+In addition, the @option{-I-} option inhibits the use of the current
+directory (where the current input file came from) as the first search
+directory for @samp{#include "@var{file}"}.  There is no way to
+override this effect of @option{-I-}.  With @option{-I.} you can specify
+searching the directory which was current when the compiler was
+invoked.  That is not exactly the same as what the preprocessor does
+by default, but it is often satisfactory.
+
+@option{-I-} does not inhibit the use of the standard system directories
+for header files.  Thus, @option{-I-} and @option{-nostdinc} are
+independent.
+
+@item -L@var{dir}
+@opindex L
+Add directory @var{dir} to the list of directories to be searched
+for @option{-l}.
+
+@item -B@var{prefix}
+@opindex B
+This option specifies where to find the executables, libraries,
+include files, and data files of the compiler itself.
+
+The compiler driver program runs one or more of the subprograms
+@file{cpp}, @file{cc1}, @file{as} and @file{ld}.  It tries
+@var{prefix} as a prefix for each program it tries to run, both with and
+without @samp{@var{machine}/@var{version}/} (@pxref{Target Options}).
+
+For each subprogram to be run, the compiler driver first tries the
+@option{-B} prefix, if any.  If that name is not found, or if @option{-B}
+was not specified, the driver tries two standard prefixes, which are
+@file{/usr/lib/gcc/} and @file{/usr/local/lib/gcc-lib/}.  If neither of
+those results in a file name that is found, the unmodified program
+name is searched for using the directories specified in your
+@env{PATH} environment variable.
+
+The compiler will check to see if the path provided by the @option{-B}
+refers to a directory, and if necessary it will add a directory
+separator character at the end of the path.
+
+@option{-B} prefixes that effectively specify directory names also apply
+to libraries in the linker, because the compiler translates these
+options into @option{-L} options for the linker.  They also apply to
+includes files in the preprocessor, because the compiler translates these
+options into @option{-isystem} options for the preprocessor.  In this case,
+the compiler appends @samp{include} to the prefix.
+
+The run-time support file @file{libgcc.a} can also be searched for using
+the @option{-B} prefix, if needed.  If it is not found there, the two
+standard prefixes above are tried, and that is all.  The file is left
+out of the link if it is not found by those means.
+
+Another way to specify a prefix much like the @option{-B} prefix is to use
+the environment variable @env{GCC_EXEC_PREFIX}.  @xref{Environment
+Variables}.
+
+As a special kludge, if the path provided by @option{-B} is
+@file{[dir/]stage@var{N}/}, where @var{N} is a number in the range 0 to
+9, then it will be replaced by @file{[dir/]include}.  This is to help
+with boot-strapping the compiler.
+
+@item -specs=@var{file}
+@opindex specs
+Process @var{file} after the compiler reads in the standard @file{specs}
+file, in order to override the defaults that the @file{gcc} driver
+program uses when determining what switches to pass to @file{cc1},
+@file{cc1plus}, @file{as}, @file{ld}, etc.  More than one
+@option{-specs=@var{file}} can be specified on the command line, and they
+are processed in order, from left to right.
+@end table
+
+@c man end
+
+@node Spec Files
+@section Specifying subprocesses and the switches to pass to them
+@cindex Spec Files
+@command{gcc} is a driver program.  It performs its job by invoking a
+sequence of other programs to do the work of compiling, assembling and
+linking.  GCC interprets its command-line parameters and uses these to
+deduce which programs it should invoke, and which command-line options
+it ought to place on their command lines.  This behavior is controlled
+by @dfn{spec strings}.  In most cases there is one spec string for each
+program that GCC can invoke, but a few programs have multiple spec
+strings to control their behavior.  The spec strings built into GCC can
+be overridden by using the @option{-specs=} command-line switch to specify
+a spec file.
+
+@dfn{Spec files} are plaintext files that are used to construct spec
+strings.  They consist of a sequence of directives separated by blank
+lines.  The type of directive is determined by the first non-whitespace
+character on the line and it can be one of the following:
+
+@table @code
+@item %@var{command}
+Issues a @var{command} to the spec file processor.  The commands that can
+appear here are:
+
+@table @code
+@item %include <@var{file}>
+@cindex %include
+Search for @var{file} and insert its text at the current point in the
+specs file.
+
+@item %include_noerr <@var{file}>
+@cindex %include_noerr
+Just like @samp{%include}, but do not generate an error message if the include
+file cannot be found.
+
+@item %rename @var{old_name} @var{new_name}
+@cindex %rename
+Rename the spec string @var{old_name} to @var{new_name}.
+
+@end table
+
+@item *[@var{spec_name}]:
+This tells the compiler to create, override or delete the named spec
+string.  All lines after this directive up to the next directive or
+blank line are considered to be the text for the spec string.  If this
+results in an empty string then the spec will be deleted.  (Or, if the
+spec did not exist, then nothing will happened.)  Otherwise, if the spec
+does not currently exist a new spec will be created.  If the spec does
+exist then its contents will be overridden by the text of this
+directive, unless the first character of that text is the @samp{+}
+character, in which case the text will be appended to the spec.
+
+@item [@var{suffix}]:
+Creates a new @samp{[@var{suffix}] spec} pair.  All lines after this directive
+and up to the next directive or blank line are considered to make up the
+spec string for the indicated suffix.  When the compiler encounters an
+input file with the named suffix, it will processes the spec string in
+order to work out how to compile that file.  For example:
+
+@smallexample
+.ZZ:
+z-compile -input %i
+@end smallexample
+
+This says that any input file whose name ends in @samp{.ZZ} should be
+passed to the program @samp{z-compile}, which should be invoked with the
+command-line switch @option{-input} and with the result of performing the
+@samp{%i} substitution.  (See below.)
+
+As an alternative to providing a spec string, the text that follows a
+suffix directive can be one of the following:
+
+@table @code
+@item @@@var{language}
+This says that the suffix is an alias for a known @var{language}.  This is
+similar to using the @option{-x} command-line switch to GCC to specify a
+language explicitly.  For example:
+
+@smallexample
+.ZZ:
+@@c++
+@end smallexample
+
+Says that .ZZ files are, in fact, C++ source files.
+
+@item #@var{name}
+This causes an error messages saying:
+
+@smallexample
+@var{name} compiler not installed on this system.
+@end smallexample
+@end table
+
+GCC already has an extensive list of suffixes built into it.
+This directive will add an entry to the end of the list of suffixes, but
+since the list is searched from the end backwards, it is effectively
+possible to override earlier entries using this technique.
+
+@end table
+
+GCC has the following spec strings built into it.  Spec files can
+override these strings or create their own.  Note that individual
+targets can also add their own spec strings to this list.
+
+@smallexample
+asm          Options to pass to the assembler
+asm_final    Options to pass to the assembler post-processor
+cpp          Options to pass to the C preprocessor
+cc1          Options to pass to the C compiler
+cc1plus      Options to pass to the C++ compiler
+endfile      Object files to include at the end of the link
+link         Options to pass to the linker
+lib          Libraries to include on the command line to the linker
+libgcc       Decides which GCC support library to pass to the linker
+linker       Sets the name of the linker
+predefines   Defines to be passed to the C preprocessor
+signed_char  Defines to pass to CPP to say whether @code{char} is signed
+             by default
+startfile    Object files to include at the start of the link
+@end smallexample
+
+Here is a small example of a spec file:
+
+@smallexample
+%rename lib                 old_lib
+
+*lib:
+--start-group -lgcc -lc -leval1 --end-group %(old_lib)
+@end smallexample
+
+This example renames the spec called @samp{lib} to @samp{old_lib} and
+then overrides the previous definition of @samp{lib} with a new one.
+The new definition adds in some extra command-line options before
+including the text of the old definition.
+
+@dfn{Spec strings} are a list of command-line options to be passed to their
+corresponding program.  In addition, the spec strings can contain
+@samp{%}-prefixed sequences to substitute variable text or to
+conditionally insert text into the command line.  Using these constructs
+it is possible to generate quite complex command lines.
+
+Here is a table of all defined @samp{%}-sequences for spec
+strings.  Note that spaces are not generated automatically around the
+results of expanding these sequences.  Therefore you can concatenate them
+together or combine them with constant text in a single argument.
+
+@table @code
+@item %%
+Substitute one @samp{%} into the program name or argument.
+
+@item %i
+Substitute the name of the input file being processed.
+
+@item %b
+Substitute the basename of the input file being processed.
+This is the substring up to (and not including) the last period
+and not including the directory.
+
+@item %B
+This is the same as @samp{%b}, but include the file suffix (text after
+the last period).
+
+@item %d
+Marks the argument containing or following the @samp{%d} as a
+temporary file name, so that that file will be deleted if GCC exits
+successfully.  Unlike @samp{%g}, this contributes no text to the
+argument.
+
+@item %g@var{suffix}
+Substitute a file name that has suffix @var{suffix} and is chosen
+once per compilation, and mark the argument in the same way as
+@samp{%d}.  To reduce exposure to denial-of-service attacks, the file
+name is now chosen in a way that is hard to predict even when previously
+chosen file names are known.  For example, @samp{%g.s @dots{} %g.o @dots{} %g.s}
+might turn into @samp{ccUVUUAU.s ccXYAXZ12.o ccUVUUAU.s}.  @var{suffix} matches
+the regexp @samp{[.A-Za-z]*} or the special string @samp{%O}, which is
+treated exactly as if @samp{%O} had been preprocessed.  Previously, @samp{%g}
+was simply substituted with a file name chosen once per compilation,
+without regard to any appended suffix (which was therefore treated
+just like ordinary text), making such attacks more likely to succeed.
+
+@item %u@var{suffix}
+Like @samp{%g}, but generates a new temporary file name even if
+@samp{%u@var{suffix}} was already seen.
+
+@item %U@var{suffix}
+Substitutes the last file name generated with @samp{%u@var{suffix}}, generating a
+new one if there is no such last file name.  In the absence of any
+@samp{%u@var{suffix}}, this is just like @samp{%g@var{suffix}}, except they don't share
+the same suffix @emph{space}, so @samp{%g.s @dots{} %U.s @dots{} %g.s @dots{} %U.s}
+would involve the generation of two distinct file names, one
+for each @samp{%g.s} and another for each @samp{%U.s}.  Previously, @samp{%U} was
+simply substituted with a file name chosen for the previous @samp{%u},
+without regard to any appended suffix.
+
+@item %j@var{SUFFIX}
+Substitutes the name of the @code{HOST_BIT_BUCKET}, if any, and if it is
+writable, and if save-temps is off; otherwise, substitute the name
+of a temporary file, just like @samp{%u}.  This temporary file is not
+meant for communication between processes, but rather as a junk
+disposal mechanism.
+
+@item %.@var{SUFFIX}
+Substitutes @var{.SUFFIX} for the suffixes of a matched switch's args
+when it is subsequently output with @samp{%*}.  @var{SUFFIX} is
+terminated by the next space or %.
+
+@item %w
+Marks the argument containing or following the @samp{%w} as the
+designated output file of this compilation.  This puts the argument
+into the sequence of arguments that @samp{%o} will substitute later.
+
+@item %o
+Substitutes the names of all the output files, with spaces
+automatically placed around them.  You should write spaces
+around the @samp{%o} as well or the results are undefined.
+@samp{%o} is for use in the specs for running the linker.
+Input files whose names have no recognized suffix are not compiled
+at all, but they are included among the output files, so they will
+be linked.
+
+@item %O
+Substitutes the suffix for object files.  Note that this is
+handled specially when it immediately follows @samp{%g, %u, or %U},
+because of the need for those to form complete file names.  The
+handling is such that @samp{%O} is treated exactly as if it had already
+been substituted, except that @samp{%g, %u, and %U} do not currently
+support additional @var{suffix} characters following @samp{%O} as they would
+following, for example, @samp{.o}.
+
+@item %p
+Substitutes the standard macro predefinitions for the
+current target machine.  Use this when running @code{cpp}.
+
+@item %P
+Like @samp{%p}, but puts @samp{__} before and after the name of each
+predefined macro, except for macros that start with @samp{__} or with
+@samp{_@var{L}}, where @var{L} is an uppercase letter.  This is for ISO
+C@.
+
+@item %I
+Substitute a @option{-iprefix} option made from @env{GCC_EXEC_PREFIX}.
+
+@item %s
+Current argument is the name of a library or startup file of some sort.
+Search for that file in a standard list of directories and substitute
+the full name found.
+
+@item %e@var{str}
+Print @var{str} as an error message.  @var{str} is terminated by a newline.
+Use this when inconsistent options are detected.
+
+@item %|
+Output @samp{-} if the input for the current command is coming from a pipe.
+
+@item %(@var{name})
+Substitute the contents of spec string @var{name} at this point.
+
+@item %[@var{name}]
+Like @samp{%(@dots{})} but put @samp{__} around @option{-D} arguments.
+
+@item %x@{@var{option}@}
+Accumulate an option for @samp{%X}.
+
+@item %X
+Output the accumulated linker options specified by @option{-Wl} or a @samp{%x}
+spec string.
+
+@item %Y
+Output the accumulated assembler options specified by @option{-Wa}.
+
+@item %Z
+Output the accumulated preprocessor options specified by @option{-Wp}.
+
+@item %v1
+Substitute the major version number of GCC@.
+(For version 2.9.5, this is 2.)
+
+@item %v2
+Substitute the minor version number of GCC@.
+(For version 2.9.5, this is 9.)
+
+@item %v3
+Substitute the patch level number of GCC@.
+(For version 2.9.5, this is 5.)
+
+@item %a
+Process the @code{asm} spec.  This is used to compute the
+switches to be passed to the assembler.
+
+@item %A
+Process the @code{asm_final} spec.  This is a spec string for
+passing switches to an assembler post-processor, if such a program is
+needed.
+
+@item %l
+Process the @code{link} spec.  This is the spec for computing the
+command line passed to the linker.  Typically it will make use of the
+@samp{%L %G %S %D and %E} sequences.
+
+@item %D
+Dump out a @option{-L} option for each directory that GCC believes might
+contain startup files.  If the target supports multilibs then the
+current multilib directory will be prepended to each of these paths.
+
+@item %M
+Output the multilib directory with directory separators replaced with
+@samp{_}.  If multilib directories are not set, or the multilib directory is
+@file{.} then this option emits nothing.
+
+@item %L
+Process the @code{lib} spec.  This is a spec string for deciding which
+libraries should be included on the command line to the linker.
+
+@item %G
+Process the @code{libgcc} spec.  This is a spec string for deciding
+which GCC support library should be included on the command line to the linker.
+
+@item %S
+Process the @code{startfile} spec.  This is a spec for deciding which
+object files should be the first ones passed to the linker.  Typically
+this might be a file named @file{crt0.o}.
+
+@item %E
+Process the @code{endfile} spec.  This is a spec string that specifies
+the last object files that will be passed to the linker.
+
+@item %C
+Process the @code{cpp} spec.  This is used to construct the arguments
+to be passed to the C preprocessor.
+
+@item %c
+Process the @code{signed_char} spec.  This is intended to be used
+to tell cpp whether a char is signed.  It typically has the definition:
+@smallexample
+%@{funsigned-char:-D__CHAR_UNSIGNED__@}
+@end smallexample
+
+@item %1
+Process the @code{cc1} spec.  This is used to construct the options to be
+passed to the actual C compiler (@samp{cc1}).
+
+@item %2
+Process the @code{cc1plus} spec.  This is used to construct the options to be
+passed to the actual C++ compiler (@samp{cc1plus}).
+
+@item %*
+Substitute the variable part of a matched option.  See below.
+Note that each comma in the substituted string is replaced by
+a single space.
+
+@item %@{@code{S}@}
+Substitutes the @code{-S} switch, if that switch was given to GCC@.
+If that switch was not specified, this substitutes nothing.  Note that
+the leading dash is omitted when specifying this option, and it is
+automatically inserted if the substitution is performed.  Thus the spec
+string @samp{%@{foo@}} would match the command-line option @option{-foo}
+and would output the command line option @option{-foo}.
+
+@item %W@{@code{S}@}
+Like %@{@code{S}@} but mark last argument supplied within as a file to be
+deleted on failure.
+
+@item %@{@code{S}*@}
+Substitutes all the switches specified to GCC whose names start
+with @code{-S}, but which also take an argument.  This is used for
+switches like @option{-o}, @option{-D}, @option{-I}, etc.
+GCC considers @option{-o foo} as being
+one switch whose names starts with @samp{o}.  %@{o*@} would substitute this
+text, including the space.  Thus two arguments would be generated.
+
+@item %@{^@code{S}*@}
+Like %@{@code{S}*@}, but don't put a blank between a switch and its
+argument.  Thus %@{^o*@} would only generate one argument, not two.
+
+@item %@{@code{S}*&@code{T}*@}
+Like %@{@code{S}*@}, but preserve order of @code{S} and @code{T} options
+(the order of @code{S} and @code{T} in the spec is not significant).
+There can be any number of ampersand-separated variables; for each the
+wild card is optional.  Useful for CPP as @samp{%@{D*&U*&A*@}}.
+
+@item %@{<@code{S}@}
+Remove all occurrences of @code{-S} from the command line.  Note---this
+command is position dependent.  @samp{%} commands in the spec string
+before this option will see @code{-S}, @samp{%} commands in the spec
+string after this option will not.
+
+@item %@{@code{S}*:@code{X}@}
+Substitutes @code{X} if one or more switches whose names start with
+@code{-S} are specified to GCC@.  Note that the tail part of the
+@code{-S} option (i.e.@: the part matched by the @samp{*}) will be substituted
+for each occurrence of @samp{%*} within @code{X}.
+
+@item %@{@code{S}:@code{X}@}
+Substitutes @code{X}, but only if the @samp{-S} switch was given to GCC@.
+
+@item %@{!@code{S}:@code{X}@}
+Substitutes @code{X}, but only if the @samp{-S} switch was @emph{not} given to GCC@.
+
+@item %@{|@code{S}:@code{X}@}
+Like %@{@code{S}:@code{X}@}, but if no @code{S} switch, substitute @samp{-}.
+
+@item %@{|!@code{S}:@code{X}@}
+Like %@{!@code{S}:@code{X}@}, but if there is an @code{S} switch, substitute @samp{-}.
+
+@item %@{.@code{S}:@code{X}@}
+Substitutes @code{X}, but only if processing a file with suffix @code{S}.
+
+@item %@{!.@code{S}:@code{X}@}
+Substitutes @code{X}, but only if @emph{not} processing a file with suffix @code{S}.
+
+@item %@{@code{S}|@code{P}:@code{X}@}
+Substitutes @code{X} if either @code{-S} or @code{-P} was given to GCC@.  This may be
+combined with @samp{!} and @samp{.} sequences as well, although they
+have a stronger binding than the @samp{|}.  For example a spec string
+like this:
+
+@smallexample
+%@{.c:-foo@} %@{!.c:-bar@} %@{.c|d:-baz@} %@{!.c|d:-boggle@}
+@end smallexample
+
+will output the following command-line options from the following input
+command-line options:
+
+@smallexample
+fred.c        -foo -baz
+jim.d         -bar -boggle
+-d fred.c     -foo -baz -boggle
+-d jim.d      -bar -baz -boggle
+@end smallexample
+
+@end table
+
+The conditional text @code{X} in a %@{@code{S}:@code{X}@} or
+%@{!@code{S}:@code{X}@} construct may contain other nested @samp{%} constructs
+or spaces, or even newlines.  They are processed as usual, as described
+above.
+
+The @option{-O}, @option{-f}, @option{-m}, and @option{-W}
+switches are handled specifically in these
+constructs.  If another value of @option{-O} or the negated form of a @option{-f}, @option{-m}, or
+@option{-W} switch is found later in the command line, the earlier switch
+value is ignored, except with @{@code{S}*@} where @code{S} is just one
+letter, which passes all matching options.
+
+The character @samp{|} at the beginning of the predicate text is used to indicate
+that a command should be piped to the following command, but only if @option{-pipe}
+is specified.
+
+It is built into GCC which switches take arguments and which do not.
+(You might think it would be useful to generalize this to allow each
+compiler's spec to say which switches take arguments.  But this cannot
+be done in a consistent fashion.  GCC cannot even decide which input
+files have been specified without knowing which switches take arguments,
+and it must know which input files to compile in order to tell which
+compilers to run).
+
+GCC also knows implicitly that arguments starting in @option{-l} are to be
+treated as compiler output files, and passed to the linker in their
+proper position among the other output files.
+
+@c man begin OPTIONS
+
+@node Target Options
+@section Specifying Target Machine and Compiler Version
+@cindex target options
+@cindex cross compiling
+@cindex specifying machine version
+@cindex specifying compiler version and target machine
+@cindex compiler version, specifying
+@cindex target machine, specifying
+
+By default, GCC compiles code for the same type of machine that you
+are using.  However, it can also be installed as a cross-compiler, to
+compile for some other type of machine.  In fact, several different
+configurations of GCC, for different target machines, can be
+installed side by side.  Then you specify which one to use with the
+@option{-b} option.
+
+In addition, older and newer versions of GCC can be installed side
+by side.  One of them (probably the newest) will be the default, but
+you may sometimes wish to use another.
+
+@table @gcctabopt
+@item -b @var{machine}
+@opindex b
+The argument @var{machine} specifies the target machine for compilation.
+This is useful when you have installed GCC as a cross-compiler.
+
+The value to use for @var{machine} is the same as was specified as the
+machine type when configuring GCC as a cross-compiler.  For
+example, if a cross-compiler was configured with @samp{configure
+i386v}, meaning to compile for an 80386 running System V, then you
+would specify @option{-b i386v} to run that cross compiler.
+
+When you do not specify @option{-b}, it normally means to compile for
+the same type of machine that you are using.
+
+@item -V @var{version}
+@opindex V
+The argument @var{version} specifies which version of GCC to run.
+This is useful when multiple versions are installed.  For example,
+@var{version} might be @samp{2.0}, meaning to run GCC version 2.0.
+
+The default version, when you do not specify @option{-V}, is the last
+version of GCC that you installed.
+@end table
+
+The @option{-b} and @option{-V} options actually work by controlling part of
+the file name used for the executable files and libraries used for
+compilation.  A given version of GCC, for a given target machine, is
+normally kept in the directory @file{/usr/local/lib/gcc-lib/@var{machine}/@var{version}}.
+
+Thus, sites can customize the effect of @option{-b} or @option{-V} either by
+changing the names of these directories or adding alternate names (or
+symbolic links).  If in directory @file{/usr/local/lib/gcc-lib/} the
+file @file{80386} is a link to the file @file{i386v}, then @option{-b
+80386} becomes an alias for @option{-b i386v}.
+
+In one respect, the @option{-b} or @option{-V} do not completely change
+to a different compiler: the top-level driver program @command{gcc}
+that you originally invoked continues to run and invoke the other
+executables (preprocessor, compiler per se, assembler and linker)
+that do the real work.  However, since no real work is done in the
+driver program, it usually does not matter that the driver program
+in use is not the one for the specified target.  It is common for the
+interface to the other executables to change incompatibly between
+compiler versions, so unless the version specified is very close to that
+of the driver (for example, @option{-V 3.0} with a driver program from GCC
+version 3.0.1), use of @option{-V} may not work; for example, using
+@option{-V 2.95.2} will not work with a driver program from GCC 3.0.
+
+The only way that the driver program depends on the target machine is
+in the parsing and handling of special machine-specific options.
+However, this is controlled by a file which is found, along with the
+other executables, in the directory for the specified version and
+target machine.  As a result, a single installed driver program adapts
+to any specified target machine, and sufficiently similar compiler
+versions.
+
+The driver program executable does control one significant thing,
+however: the default version and target machine.  Therefore, you can
+install different instances of the driver program, compiled for
+different targets or versions, under different names.
+
+For example, if the driver for version 2.0 is installed as @command{ogcc}
+and that for version 2.1 is installed as @command{gcc}, then the command
+@command{gcc} will use version 2.1 by default, while @command{ogcc} will use
+2.0 by default.  However, you can choose either version with either
+command with the @option{-V} option.
+
+@node Submodel Options
+@section Hardware Models and Configurations
+@cindex submodel options
+@cindex specifying hardware config
+@cindex hardware models and configurations, specifying
+@cindex machine dependent options
+
+Earlier we discussed the standard option @option{-b} which chooses among
+different installed compilers for completely different target
+machines, such as VAX vs.@: 68000 vs.@: 80386.
+
+In addition, each of these target machine types can have its own
+special options, starting with @samp{-m}, to choose among various
+hardware models or configurations---for example, 68010 vs 68020,
+floating coprocessor or none.  A single installed version of the
+compiler can compile for any model or configuration, according to the
+options specified.
+
+Some configurations of the compiler also support additional special
+options, usually for compatibility with other compilers on the same
+platform.
+
+These options are defined by the macro @code{TARGET_SWITCHES} in the
+machine description.  The default for the options is also defined by
+that macro, which enables you to change the defaults.
+
+@menu
+* M680x0 Options::
+* M68hc1x Options::
+* VAX Options::
+* SPARC Options::
+* Convex Options::
+* AMD29K Options::
+* ARM Options::
+* MN10200 Options::
+* MN10300 Options::
+* M32R/D Options::
+* M88K Options::
+* RS/6000 and PowerPC Options::
+* RT Options::
+* MIPS Options::
+* i386 and x86-64 Options::
+* HPPA Options::
+* Intel 960 Options::
+* DEC Alpha Options::
+* DEC Alpha/VMS Options::
+* Clipper Options::
+* H8/300 Options::
+* SH Options::
+* System V Options::
+* TMS320C3x/C4x Options::
+* V850 Options::
+* ARC Options::
+* NS32K Options::
+* AVR Options::
+* MCore Options::
+* IA-64 Options::
+* D30V Options::
+* S/390 and zSeries Options::
+* CRIS Options::
+* MMIX Options::
+* PDP-11 Options::
+* Xstormy16 Options::
+* Xtensa Options::
+@end menu
+
+@node M680x0 Options
+@subsection M680x0 Options
+@cindex M680x0 options
+
+These are the @samp{-m} options defined for the 68000 series.  The default
+values for these options depends on which style of 68000 was selected when
+the compiler was configured; the defaults for the most common choices are
+given below.
+
+@table @gcctabopt
+@item -m68000
+@itemx -mc68000
+@opindex m68000
+@opindex mc68000
+Generate output for a 68000.  This is the default
+when the compiler is configured for 68000-based systems.
+
+Use this option for microcontrollers with a 68000 or EC000 core,
+including the 68008, 68302, 68306, 68307, 68322, 68328 and 68356.
+
+@item -m68020
+@itemx -mc68020
+@opindex m68020
+@opindex mc68020
+Generate output for a 68020.  This is the default
+when the compiler is configured for 68020-based systems.
+
+@item -m68881
+@opindex m68881
+Generate output containing 68881 instructions for floating point.
+This is the default for most 68020 systems unless @option{--nfp} was
+specified when the compiler was configured.
+
+@item -m68030
+@opindex m68030
+Generate output for a 68030.  This is the default when the compiler is
+configured for 68030-based systems.
+
+@item -m68040
+@opindex m68040
+Generate output for a 68040.  This is the default when the compiler is
+configured for 68040-based systems.
+
+This option inhibits the use of 68881/68882 instructions that have to be
+emulated by software on the 68040.  Use this option if your 68040 does not
+have code to emulate those instructions.
+
+@item -m68060
+@opindex m68060
+Generate output for a 68060.  This is the default when the compiler is
+configured for 68060-based systems.
+
+This option inhibits the use of 68020 and 68881/68882 instructions that
+have to be emulated by software on the 68060.  Use this option if your 68060
+does not have code to emulate those instructions.
+
+@item -mcpu32
+@opindex mcpu32
+Generate output for a CPU32.  This is the default
+when the compiler is configured for CPU32-based systems.
+
+Use this option for microcontrollers with a
+CPU32 or CPU32+ core, including the 68330, 68331, 68332, 68333, 68334,
+68336, 68340, 68341, 68349 and 68360.
+
+@item -m5200
+@opindex m5200
+Generate output for a 520X ``coldfire'' family cpu.  This is the default
+when the compiler is configured for 520X-based systems.
+
+Use this option for microcontroller with a 5200 core, including
+the MCF5202, MCF5203, MCF5204 and MCF5202.
+
+
+@item -m68020-40
+@opindex m68020-40
+Generate output for a 68040, without using any of the new instructions.
+This results in code which can run relatively efficiently on either a
+68020/68881 or a 68030 or a 68040.  The generated code does use the
+68881 instructions that are emulated on the 68040.
+
+@item -m68020-60
+@opindex m68020-60
+Generate output for a 68060, without using any of the new instructions.
+This results in code which can run relatively efficiently on either a
+68020/68881 or a 68030 or a 68040.  The generated code does use the
+68881 instructions that are emulated on the 68060.
+
+@item -mfpa
+@opindex mfpa
+Generate output containing Sun FPA instructions for floating point.
+
+@item -msoft-float
+@opindex msoft-float
+Generate output containing library calls for floating point.
+@strong{Warning:} the requisite libraries are not available for all m68k
+targets.  Normally the facilities of the machine's usual C compiler are
+used, but this can't be done directly in cross-compilation.  You must
+make your own arrangements to provide suitable library functions for
+cross-compilation.  The embedded targets @samp{m68k-*-aout} and
+@samp{m68k-*-coff} do provide software floating point support.
+
+@item -mshort
+@opindex mshort
+Consider type @code{int} to be 16 bits wide, like @code{short int}.
+
+@item -mnobitfield
+@opindex mnobitfield
+Do not use the bit-field instructions.  The @option{-m68000}, @option{-mcpu32}
+and @option{-m5200} options imply @w{@option{-mnobitfield}}.
+
+@item -mbitfield
+@opindex mbitfield
+Do use the bit-field instructions.  The @option{-m68020} option implies
+@option{-mbitfield}.  This is the default if you use a configuration
+designed for a 68020.
+
+@item -mrtd
+@opindex mrtd
+Use a different function-calling convention, in which functions
+that take a fixed number of arguments return with the @code{rtd}
+instruction, which pops their arguments while returning.  This
+saves one instruction in the caller since there is no need to pop
+the arguments there.
+
+This calling convention is incompatible with the one normally
+used on Unix, so you cannot use it if you need to call libraries
+compiled with the Unix compiler.
+
+Also, you must provide function prototypes for all functions that
+take variable numbers of arguments (including @code{printf});
+otherwise incorrect code will be generated for calls to those
+functions.
+
+In addition, seriously incorrect code will result if you call a
+function with too many arguments.  (Normally, extra arguments are
+harmlessly ignored.)
+
+The @code{rtd} instruction is supported by the 68010, 68020, 68030,
+68040, 68060 and CPU32 processors, but not by the 68000 or 5200.
+
+@item -malign-int
+@itemx -mno-align-int
+@opindex malign-int
+@opindex mno-align-int
+Control whether GCC aligns @code{int}, @code{long}, @code{long long},
+@code{float}, @code{double}, and @code{long double} variables on a 32-bit
+boundary (@option{-malign-int}) or a 16-bit boundary (@option{-mno-align-int}).
+Aligning variables on 32-bit boundaries produces code that runs somewhat
+faster on processors with 32-bit busses at the expense of more memory.
+
+@strong{Warning:} if you use the @option{-malign-int} switch, GCC will
+align structures containing the above types  differently than
+most published application binary interface specifications for the m68k.
+
+@item -mpcrel
+@opindex mpcrel
+Use the pc-relative addressing mode of the 68000 directly, instead of
+using a global offset table.  At present, this option implies @option{-fpic},
+allowing at most a 16-bit offset for pc-relative addressing.  @option{-fPIC} is
+not presently supported with @option{-mpcrel}, though this could be supported for
+68020 and higher processors.
+
+@item -mno-strict-align
+@itemx -mstrict-align
+@opindex mno-strict-align
+@opindex mstrict-align
+Do not (do) assume that unaligned memory references will be handled by
+the system.
+
+@end table
+
+@node M68hc1x Options
+@subsection M68hc1x Options
+@cindex M68hc1x options
+
+These are the @samp{-m} options defined for the 68hc11 and 68hc12
+microcontrollers.  The default values for these options depends on
+which style of microcontroller was selected when the compiler was configured;
+the defaults for the most common choices are given below.
+
+@table @gcctabopt
+@item -m6811
+@itemx -m68hc11
+@opindex m6811
+@opindex m68hc11
+Generate output for a 68HC11.  This is the default
+when the compiler is configured for 68HC11-based systems.
+
+@item -m6812
+@itemx -m68hc12
+@opindex m6812
+@opindex m68hc12
+Generate output for a 68HC12.  This is the default
+when the compiler is configured for 68HC12-based systems.
+
+@item -mauto-incdec
+@opindex mauto-incdec
+Enable the use of 68HC12 pre and post auto-increment and auto-decrement
+addressing modes.
+
+@item -mshort
+@opindex mshort
+Consider type @code{int} to be 16 bits wide, like @code{short int}.
+
+@item -msoft-reg-count=@var{count}
+@opindex msoft-reg-count
+Specify the number of pseudo-soft registers which are used for the
+code generation.  The maximum number is 32.  Using more pseudo-soft
+register may or may not result in better code depending on the program.
+The default is 4 for 68HC11 and 2 for 68HC12.
+
+@end table
+
+@node VAX Options
+@subsection VAX Options
+@cindex VAX options
+
+These @samp{-m} options are defined for the VAX:
+
+@table @gcctabopt
+@item -munix
+@opindex munix
+Do not output certain jump instructions (@code{aobleq} and so on)
+that the Unix assembler for the VAX cannot handle across long
+ranges.
+
+@item -mgnu
+@opindex mgnu
+Do output those jump instructions, on the assumption that you
+will assemble with the GNU assembler.
+
+@item -mg
+@opindex mg
+Output code for g-format floating point numbers instead of d-format.
+@end table
+
+@node SPARC Options
+@subsection SPARC Options
+@cindex SPARC options
+
+These @samp{-m} switches are supported on the SPARC:
+
+@table @gcctabopt
+@item -mno-app-regs
+@itemx -mapp-regs
+@opindex mno-app-regs
+@opindex mapp-regs
+Specify @option{-mapp-regs} to generate output using the global registers
+2 through 4, which the SPARC SVR4 ABI reserves for applications.  This
+is the default.
+
+To be fully SVR4 ABI compliant at the cost of some performance loss,
+specify @option{-mno-app-regs}.  You should compile libraries and system
+software with this option.
+
+@item -mfpu
+@itemx -mhard-float
+@opindex mfpu
+@opindex mhard-float
+Generate output containing floating point instructions.  This is the
+default.
+
+@item -mno-fpu
+@itemx -msoft-float
+@opindex mno-fpu
+@opindex msoft-float
+Generate output containing library calls for floating point.
+@strong{Warning:} the requisite libraries are not available for all SPARC
+targets.  Normally the facilities of the machine's usual C compiler are
+used, but this cannot be done directly in cross-compilation.  You must make
+your own arrangements to provide suitable library functions for
+cross-compilation.  The embedded targets @samp{sparc-*-aout} and
+@samp{sparclite-*-*} do provide software floating point support.
+
+@option{-msoft-float} changes the calling convention in the output file;
+therefore, it is only useful if you compile @emph{all} of a program with
+this option.  In particular, you need to compile @file{libgcc.a}, the
+library that comes with GCC, with @option{-msoft-float} in order for
+this to work.
+
+@item -mhard-quad-float
+@opindex mhard-quad-float
+Generate output containing quad-word (long double) floating point
+instructions.
+
+@item -msoft-quad-float
+@opindex msoft-quad-float
+Generate output containing library calls for quad-word (long double)
+floating point instructions.  The functions called are those specified
+in the SPARC ABI@.  This is the default.
+
+As of this writing, there are no sparc implementations that have hardware
+support for the quad-word floating point instructions.  They all invoke
+a trap handler for one of these instructions, and then the trap handler
+emulates the effect of the instruction.  Because of the trap handler overhead,
+this is much slower than calling the ABI library routines.  Thus the
+@option{-msoft-quad-float} option is the default.
+
+@item -mno-epilogue
+@itemx -mepilogue
+@opindex mno-epilogue
+@opindex mepilogue
+With @option{-mepilogue} (the default), the compiler always emits code for
+function exit at the end of each function.  Any function exit in
+the middle of the function (such as a return statement in C) will
+generate a jump to the exit code at the end of the function.
+
+With @option{-mno-epilogue}, the compiler tries to emit exit code inline
+at every function exit.
+
+@item -mno-flat
+@itemx -mflat
+@opindex mno-flat
+@opindex mflat
+With @option{-mflat}, the compiler does not generate save/restore instructions
+and will use a ``flat'' or single register window calling convention.
+This model uses %i7 as the frame pointer and is compatible with the normal
+register window model.  Code from either may be intermixed.
+The local registers and the input registers (0--5) are still treated as
+``call saved'' registers and will be saved on the stack as necessary.
+
+With @option{-mno-flat} (the default), the compiler emits save/restore
+instructions (except for leaf functions) and is the normal mode of operation.
+
+@item -mno-unaligned-doubles
+@itemx -munaligned-doubles
+@opindex mno-unaligned-doubles
+@opindex munaligned-doubles
+Assume that doubles have 8 byte alignment.  This is the default.
+
+With @option{-munaligned-doubles}, GCC assumes that doubles have 8 byte
+alignment only if they are contained in another type, or if they have an
+absolute address.  Otherwise, it assumes they have 4 byte alignment.
+Specifying this option avoids some rare compatibility problems with code
+generated by other compilers.  It is not the default because it results
+in a performance loss, especially for floating point code.
+
+@item -mno-faster-structs
+@itemx -mfaster-structs
+@opindex mno-faster-structs
+@opindex mfaster-structs
+With @option{-mfaster-structs}, the compiler assumes that structures
+should have 8 byte alignment.  This enables the use of pairs of
+@code{ldd} and @code{std} instructions for copies in structure
+assignment, in place of twice as many @code{ld} and @code{st} pairs.
+However, the use of this changed alignment directly violates the Sparc
+ABI@.  Thus, it's intended only for use on targets where the developer
+acknowledges that their resulting code will not be directly in line with
+the rules of the ABI@.
+
+@item -mv8
+@itemx -msparclite
+@opindex mv8
+@opindex msparclite
+These two options select variations on the SPARC architecture.
+
+By default (unless specifically configured for the Fujitsu SPARClite),
+GCC generates code for the v7 variant of the SPARC architecture.
+
+@option{-mv8} will give you SPARC v8 code.  The only difference from v7
+code is that the compiler emits the integer multiply and integer
+divide instructions which exist in SPARC v8 but not in SPARC v7.
+
+@option{-msparclite} will give you SPARClite code.  This adds the integer
+multiply, integer divide step and scan (@code{ffs}) instructions which
+exist in SPARClite but not in SPARC v7.
+
+These options are deprecated and will be deleted in a future GCC release.
+They have been replaced with @option{-mcpu=xxx}.
+
+@item -mcypress
+@itemx -msupersparc
+@opindex mcypress
+@opindex msupersparc
+These two options select the processor for which the code is optimized.
+
+With @option{-mcypress} (the default), the compiler optimizes code for the
+Cypress CY7C602 chip, as used in the SparcStation/SparcServer 3xx series.
+This is also appropriate for the older SparcStation 1, 2, IPX etc.
+
+With @option{-msupersparc} the compiler optimizes code for the SuperSparc cpu, as
+used in the SparcStation 10, 1000 and 2000 series.  This flag also enables use
+of the full SPARC v8 instruction set.
+
+These options are deprecated and will be deleted in a future GCC release.
+They have been replaced with @option{-mcpu=xxx}.
+
+@item -mcpu=@var{cpu_type}
+@opindex mcpu
+Set the instruction set, register set, and instruction scheduling parameters
+for machine type @var{cpu_type}.  Supported values for @var{cpu_type} are
+@samp{v7}, @samp{cypress}, @samp{v8}, @samp{supersparc}, @samp{sparclite},
+@samp{hypersparc}, @samp{sparclite86x}, @samp{f930}, @samp{f934},
+@samp{sparclet}, @samp{tsc701}, @samp{v9}, and @samp{ultrasparc}.
+
+Default instruction scheduling parameters are used for values that select
+an architecture and not an implementation.  These are @samp{v7}, @samp{v8},
+@samp{sparclite}, @samp{sparclet}, @samp{v9}.
+
+Here is a list of each supported architecture and their supported
+implementations.
+
+@smallexample
+    v7:             cypress
+    v8:             supersparc, hypersparc
+    sparclite:      f930, f934, sparclite86x
+    sparclet:       tsc701
+    v9:             ultrasparc
+@end smallexample
+
+@item -mtune=@var{cpu_type}
+@opindex mtune
+Set the instruction scheduling parameters for machine type
+@var{cpu_type}, but do not set the instruction set or register set that the
+option @option{-mcpu=@var{cpu_type}} would.
+
+The same values for @option{-mcpu=@var{cpu_type}} can be used for
+@option{-mtune=@var{cpu_type}}, but the only useful values are those
+that select a particular cpu implementation.  Those are @samp{cypress},
+@samp{supersparc}, @samp{hypersparc}, @samp{f930}, @samp{f934},
+@samp{sparclite86x}, @samp{tsc701}, and @samp{ultrasparc}.
+
+@end table
+
+These @samp{-m} switches are supported in addition to the above
+on the SPARCLET processor.
+
+@table @gcctabopt
+@item -mlittle-endian
+@opindex mlittle-endian
+Generate code for a processor running in little-endian mode.
+
+@item -mlive-g0
+@opindex mlive-g0
+Treat register @code{%g0} as a normal register.
+GCC will continue to clobber it as necessary but will not assume
+it always reads as 0.
+
+@item -mbroken-saverestore
+@opindex mbroken-saverestore
+Generate code that does not use non-trivial forms of the @code{save} and
+@code{restore} instructions.  Early versions of the SPARCLET processor do
+not correctly handle @code{save} and @code{restore} instructions used with
+arguments.  They correctly handle them used without arguments.  A @code{save}
+instruction used without arguments increments the current window pointer
+but does not allocate a new stack frame.  It is assumed that the window
+overflow trap handler will properly handle this case as will interrupt
+handlers.
+@end table
+
+These @samp{-m} switches are supported in addition to the above
+on SPARC V9 processors in 64-bit environments.
+
+@table @gcctabopt
+@item -mlittle-endian
+@opindex mlittle-endian
+Generate code for a processor running in little-endian mode.
+
+@item -m32
+@itemx -m64
+@opindex m32
+@opindex m64
+Generate code for a 32-bit or 64-bit environment.
+The 32-bit environment sets int, long and pointer to 32 bits.
+The 64-bit environment sets int to 32 bits and long and pointer
+to 64 bits.
+
+@item -mcmodel=medlow
+@opindex mcmodel=medlow
+Generate code for the Medium/Low code model: the program must be linked
+in the low 32 bits of the address space.  Pointers are 64 bits.
+Programs can be statically or dynamically linked.
+
+@item -mcmodel=medmid
+@opindex mcmodel=medmid
+Generate code for the Medium/Middle code model: the program must be linked
+in the low 44 bits of the address space, the text segment must be less than
+2G bytes, and data segment must be within 2G of the text segment.
+Pointers are 64 bits.
+
+@item -mcmodel=medany
+@opindex mcmodel=medany
+Generate code for the Medium/Anywhere code model: the program may be linked
+anywhere in the address space, the text segment must be less than
+2G bytes, and data segment must be within 2G of the text segment.
+Pointers are 64 bits.
+
+@item -mcmodel=embmedany
+@opindex mcmodel=embmedany
+Generate code for the Medium/Anywhere code model for embedded systems:
+assume a 32-bit text and a 32-bit data segment, both starting anywhere
+(determined at link time).  Register %g4 points to the base of the
+data segment.  Pointers are still 64 bits.
+Programs are statically linked, PIC is not supported.
+
+@item -mstack-bias
+@itemx -mno-stack-bias
+@opindex mstack-bias
+@opindex mno-stack-bias
+With @option{-mstack-bias}, GCC assumes that the stack pointer, and
+frame pointer if present, are offset by @minus{}2047 which must be added back
+when making stack frame references.
+Otherwise, assume no such offset is present.
+@end table
+
+@node Convex Options
+@subsection Convex Options
+@cindex Convex options
+
+These @samp{-m} options are defined for Convex:
+
+@table @gcctabopt
+@item -mc1
+@opindex mc1
+Generate output for C1.  The code will run on any Convex machine.
+The preprocessor symbol @code{__convex__c1__} is defined.
+
+@item -mc2
+@opindex mc2
+Generate output for C2.  Uses instructions not available on C1.
+Scheduling and other optimizations are chosen for max performance on C2.
+The preprocessor symbol @code{__convex_c2__} is defined.
+
+@item -mc32
+@opindex mc32
+Generate output for C32xx.  Uses instructions not available on C1.
+Scheduling and other optimizations are chosen for max performance on C32.
+The preprocessor symbol @code{__convex_c32__} is defined.
+
+@item -mc34
+@opindex mc34
+Generate output for C34xx.  Uses instructions not available on C1.
+Scheduling and other optimizations are chosen for max performance on C34.
+The preprocessor symbol @code{__convex_c34__} is defined.
+
+@item -mc38
+@opindex mc38
+Generate output for C38xx.  Uses instructions not available on C1.
+Scheduling and other optimizations are chosen for max performance on C38.
+The preprocessor symbol @code{__convex_c38__} is defined.
+
+@item -margcount
+@opindex margcount
+Generate code which puts an argument count in the word preceding each
+argument list.  This is compatible with regular CC, and a few programs
+may need the argument count word.  GDB and other source-level debuggers
+do not need it; this info is in the symbol table.
+
+@item -mnoargcount
+@opindex mnoargcount
+Omit the argument count word.  This is the default.
+
+@item -mvolatile-cache
+@opindex mvolatile-cache
+Allow volatile references to be cached.  This is the default.
+
+@item -mvolatile-nocache
+@opindex mvolatile-nocache
+Volatile references bypass the data cache, going all the way to memory.
+This is only needed for multi-processor code that does not use standard
+synchronization instructions.  Making non-volatile references to volatile
+locations will not necessarily work.
+
+@item -mlong32
+@opindex mlong32
+Type long is 32 bits, the same as type int.  This is the default.
+
+@item -mlong64
+@opindex mlong64
+Type long is 64 bits, the same as type long long.  This option is useless,
+because no library support exists for it.
+@end table
+
+@node AMD29K Options
+@subsection AMD29K Options
+@cindex AMD29K options
+
+These @samp{-m} options are defined for the AMD Am29000:
+
+@table @gcctabopt
+@item -mdw
+@opindex mdw
+@cindex DW bit (29k)
+Generate code that assumes the @code{DW} bit is set, i.e., that byte and
+halfword operations are directly supported by the hardware.  This is the
+default.
+
+@item -mndw
+@opindex mndw
+Generate code that assumes the @code{DW} bit is not set.
+
+@item -mbw
+@opindex mbw
+@cindex byte writes (29k)
+Generate code that assumes the system supports byte and halfword write
+operations.  This is the default.
+
+@item -mnbw
+@opindex mnbw
+Generate code that assumes the systems does not support byte and
+halfword write operations.  @option{-mnbw} implies @option{-mndw}.
+
+@item -msmall
+@opindex msmall
+@cindex memory model (29k)
+Use a small memory model that assumes that all function addresses are
+either within a single 256 KB segment or at an absolute address of less
+than 256k.  This allows the @code{call} instruction to be used instead
+of a @code{const}, @code{consth}, @code{calli} sequence.
+
+@item -mnormal
+@opindex mnormal
+Use the normal memory model: Generate @code{call} instructions only when
+calling functions in the same file and @code{calli} instructions
+otherwise.  This works if each file occupies less than 256 KB but allows
+the entire executable to be larger than 256 KB@.  This is the default.
+
+@item -mlarge
+@opindex mlarge
+Always use @code{calli} instructions.  Specify this option if you expect
+a single file to compile into more than 256 KB of code.
+
+@item -m29050
+@opindex m29050
+@cindex processor selection (29k)
+Generate code for the Am29050.
+
+@item -m29000
+@opindex m29000
+Generate code for the Am29000.  This is the default.
+
+@item -mkernel-registers
+@opindex mkernel-registers
+@cindex kernel and user registers (29k)
+Generate references to registers @code{gr64-gr95} instead of to
+registers @code{gr96-gr127}.  This option can be used when compiling
+kernel code that wants a set of global registers disjoint from that used
+by user-mode code.
+
+Note that when this option is used, register names in @samp{-f} flags
+must use the normal, user-mode, names.
+
+@item -muser-registers
+@opindex muser-registers
+Use the normal set of global registers, @code{gr96-gr127}.  This is the
+default.
+
+@item -mstack-check
+@itemx -mno-stack-check
+@opindex mstack-check
+@opindex mno-stack-check
+@cindex stack checks (29k)
+Insert (or do not insert) a call to @code{__msp_check} after each stack
+adjustment.  This is often used for kernel code.
+
+@item -mstorem-bug
+@itemx -mno-storem-bug
+@opindex mstorem-bug
+@opindex mno-storem-bug
+@cindex storem bug (29k)
+@option{-mstorem-bug} handles 29k processors which cannot handle the
+separation of a mtsrim insn and a storem instruction (most 29000 chips
+to date, but not the 29050).
+
+@item -mno-reuse-arg-regs
+@itemx -mreuse-arg-regs
+@opindex mno-reuse-arg-regs
+@opindex mreuse-arg-regs
+@option{-mno-reuse-arg-regs} tells the compiler to only use incoming argument
+registers for copying out arguments.  This helps detect calling a function
+with fewer arguments than it was declared with.
+
+@item -mno-impure-text
+@itemx -mimpure-text
+@opindex mno-impure-text
+@opindex mimpure-text
+@option{-mimpure-text}, used in addition to @option{-shared}, tells the compiler to
+not pass @option{-assert pure-text} to the linker when linking a shared object.
+
+@item -msoft-float
+@opindex msoft-float
+Generate output containing library calls for floating point.
+@strong{Warning:} the requisite libraries are not part of GCC@.
+Normally the facilities of the machine's usual C compiler are used, but
+this can't be done directly in cross-compilation.  You must make your
+own arrangements to provide suitable library functions for
+cross-compilation.
+
+@item -mno-multm
+@opindex mno-multm
+Do not generate multm or multmu instructions.  This is useful for some embedded
+systems which do not have trap handlers for these instructions.
+@end table
+
+@node ARM Options
+@subsection ARM Options
+@cindex ARM options
+
+These @samp{-m} options are defined for Advanced RISC Machines (ARM)
+architectures:
+
+@table @gcctabopt
+@item -mapcs-frame
+@opindex mapcs-frame
+Generate a stack frame that is compliant with the ARM Procedure Call
+Standard for all functions, even if this is not strictly necessary for
+correct execution of the code.  Specifying @option{-fomit-frame-pointer}
+with this option will cause the stack frames not to be generated for
+leaf functions.  The default is @option{-mno-apcs-frame}.
+
+@item -mapcs
+@opindex mapcs
+This is a synonym for @option{-mapcs-frame}.
+
+@item -mapcs-26
+@opindex mapcs-26
+Generate code for a processor running with a 26-bit program counter,
+and conforming to the function calling standards for the APCS 26-bit
+option.  This option replaces the @option{-m2} and @option{-m3} options
+of previous releases of the compiler.
+
+@item -mapcs-32
+@opindex mapcs-32
+Generate code for a processor running with a 32-bit program counter,
+and conforming to the function calling standards for the APCS 32-bit
+option.  This option replaces the @option{-m6} option of previous releases
+of the compiler.
+
+@ignore
+@c not currently implemented
+@item -mapcs-stack-check
+@opindex mapcs-stack-check
+Generate code to check the amount of stack space available upon entry to
+every function (that actually uses some stack space).  If there is
+insufficient space available then either the function
+@samp{__rt_stkovf_split_small} or @samp{__rt_stkovf_split_big} will be
+called, depending upon the amount of stack space required.  The run time
+system is required to provide these functions.  The default is
+@option{-mno-apcs-stack-check}, since this produces smaller code.
+
+@c not currently implemented
+@item -mapcs-float
+@opindex mapcs-float
+Pass floating point arguments using the float point registers.  This is
+one of the variants of the APCS@.  This option is recommended if the
+target hardware has a floating point unit or if a lot of floating point
+arithmetic is going to be performed by the code.  The default is
+@option{-mno-apcs-float}, since integer only code is slightly increased in
+size if @option{-mapcs-float} is used.
+
+@c not currently implemented
+@item -mapcs-reentrant
+@opindex mapcs-reentrant
+Generate reentrant, position independent code.  The default is
+@option{-mno-apcs-reentrant}.
+@end ignore
+
+@item -mthumb-interwork
+@opindex mthumb-interwork
+Generate code which supports calling between the ARM and Thumb
+instruction sets.  Without this option the two instruction sets cannot
+be reliably used inside one program.  The default is
+@option{-mno-thumb-interwork}, since slightly larger code is generated
+when @option{-mthumb-interwork} is specified.
+
+@item -mno-sched-prolog
+@opindex mno-sched-prolog
+Prevent the reordering of instructions in the function prolog, or the
+merging of those instruction with the instructions in the function's
+body.  This means that all functions will start with a recognizable set
+of instructions (or in fact one of a choice from a small set of
+different function prologues), and this information can be used to
+locate the start if functions inside an executable piece of code.  The
+default is @option{-msched-prolog}.
+
+@item -mhard-float
+@opindex mhard-float
+Generate output containing floating point instructions.  This is the
+default.
+
+@item -msoft-float
+@opindex msoft-float
+Generate output containing library calls for floating point.
+@strong{Warning:} the requisite libraries are not available for all ARM
+targets.  Normally the facilities of the machine's usual C compiler are
+used, but this cannot be done directly in cross-compilation.  You must make
+your own arrangements to provide suitable library functions for
+cross-compilation.
+
+@option{-msoft-float} changes the calling convention in the output file;
+therefore, it is only useful if you compile @emph{all} of a program with
+this option.  In particular, you need to compile @file{libgcc.a}, the
+library that comes with GCC, with @option{-msoft-float} in order for
+this to work.
+
+@item -mlittle-endian
+@opindex mlittle-endian
+Generate code for a processor running in little-endian mode.  This is
+the default for all standard configurations.
+
+@item -mbig-endian
+@opindex mbig-endian
+Generate code for a processor running in big-endian mode; the default is
+to compile code for a little-endian processor.
+
+@item -mwords-little-endian
+@opindex mwords-little-endian
+This option only applies when generating code for big-endian processors.
+Generate code for a little-endian word order but a big-endian byte
+order.  That is, a byte order of the form @samp{32107654}.  Note: this
+option should only be used if you require compatibility with code for
+big-endian ARM processors generated by versions of the compiler prior to
+2.8.
+
+@item -malignment-traps
+@opindex malignment-traps
+Generate code that will not trap if the MMU has alignment traps enabled.
+On ARM architectures prior to ARMv4, there were no instructions to
+access half-word objects stored in memory.  However, when reading from
+memory a feature of the ARM architecture allows a word load to be used,
+even if the address is unaligned, and the processor core will rotate the
+data as it is being loaded.  This option tells the compiler that such
+misaligned accesses will cause a MMU trap and that it should instead
+synthesise the access as a series of byte accesses.  The compiler can
+still use word accesses to load half-word data if it knows that the
+address is aligned to a word boundary.
+
+This option is ignored when compiling for ARM architecture 4 or later,
+since these processors have instructions to directly access half-word
+objects in memory.
+
+@item -mno-alignment-traps
+@opindex mno-alignment-traps
+Generate code that assumes that the MMU will not trap unaligned
+accesses.  This produces better code when the target instruction set
+does not have half-word memory operations (i.e.@: implementations prior to
+ARMv4).
+
+Note that you cannot use this option to access unaligned word objects,
+since the processor will only fetch one 32-bit aligned object from
+memory.
+
+The default setting for most targets is @option{-mno-alignment-traps}, since
+this produces better code when there are no half-word memory
+instructions available.
+
+@item -mshort-load-bytes
+@itemx -mno-short-load-words
+@opindex mshort-load-bytes
+@opindex mno-short-load-words
+These are deprecated aliases for @option{-malignment-traps}.
+
+@item -mno-short-load-bytes
+@itemx -mshort-load-words
+@opindex mno-short-load-bytes
+@opindex mshort-load-words
+This are deprecated aliases for @option{-mno-alignment-traps}.
+
+@item -mbsd
+@opindex mbsd
+This option only applies to RISC iX@.  Emulate the native BSD-mode
+compiler.  This is the default if @option{-ansi} is not specified.
+
+@item -mxopen
+@opindex mxopen
+This option only applies to RISC iX@.  Emulate the native X/Open-mode
+compiler.
+
+@item -mno-symrename
+@opindex mno-symrename
+This option only applies to RISC iX@.  Do not run the assembler
+post-processor, @samp{symrename}, after code has been assembled.
+Normally it is necessary to modify some of the standard symbols in
+preparation for linking with the RISC iX C library; this option
+suppresses this pass.  The post-processor is never run when the
+compiler is built for cross-compilation.
+
+@item -mcpu=@var{name}
+@opindex mcpu
+This specifies the name of the target ARM processor.  GCC uses this name
+to determine what kind of instructions it can emit when generating
+assembly code.  Permissible names are: @samp{arm2}, @samp{arm250},
+@samp{arm3}, @samp{arm6}, @samp{arm60}, @samp{arm600}, @samp{arm610},
+@samp{arm620}, @samp{arm7}, @samp{arm7m}, @samp{arm7d}, @samp{arm7dm},
+@samp{arm7di}, @samp{arm7dmi}, @samp{arm70}, @samp{arm700},
+@samp{arm700i}, @samp{arm710}, @samp{arm710c}, @samp{arm7100},
+@samp{arm7500}, @samp{arm7500fe}, @samp{arm7tdmi}, @samp{arm8},
+@samp{strongarm}, @samp{strongarm110}, @samp{strongarm1100},
+@samp{arm8}, @samp{arm810}, @samp{arm9}, @samp{arm9e}, @samp{arm920},
+@samp{arm920t}, @samp{arm940t}, @samp{arm9tdmi}, @samp{arm10tdmi},
+@samp{arm1020t}, @samp{xscale}.
+
+@itemx -mtune=@var{name}
+@opindex mtune
+This option is very similar to the @option{-mcpu=} option, except that
+instead of specifying the actual target processor type, and hence
+restricting which instructions can be used, it specifies that GCC should
+tune the performance of the code as if the target were of the type
+specified in this option, but still choosing the instructions that it
+will generate based on the cpu specified by a @option{-mcpu=} option.
+For some ARM implementations better performance can be obtained by using
+this option.
+
+@item -march=@var{name}
+@opindex march
+This specifies the name of the target ARM architecture.  GCC uses this
+name to determine what kind of instructions it can emit when generating
+assembly code.  This option can be used in conjunction with or instead
+of the @option{-mcpu=} option.  Permissible names are: @samp{armv2},
+@samp{armv2a}, @samp{armv3}, @samp{armv3m}, @samp{armv4}, @samp{armv4t},
+@samp{armv5}, @samp{armv5t}, @samp{armv5te}.
+
+@item -mfpe=@var{number}
+@itemx -mfp=@var{number}
+@opindex mfpe
+@opindex mfp
+This specifies the version of the floating point emulation available on
+the target.  Permissible values are 2 and 3.  @option{-mfp=} is a synonym
+for @option{-mfpe=}, for compatibility with older versions of GCC@.
+
+@item -mstructure-size-boundary=@var{n}
+@opindex mstructure-size-boundary
+The size of all structures and unions will be rounded up to a multiple
+of the number of bits set by this option.  Permissible values are 8 and
+32.  The default value varies for different toolchains.  For the COFF
+targeted toolchain the default value is 8.  Specifying the larger number
+can produce faster, more efficient code, but can also increase the size
+of the program.  The two values are potentially incompatible.  Code
+compiled with one value cannot necessarily expect to work with code or
+libraries compiled with the other value, if they exchange information
+using structures or unions.
+
+@item -mabort-on-noreturn
+@opindex mabort-on-noreturn
+Generate a call to the function @code{abort} at the end of a
+@code{noreturn} function.  It will be executed if the function tries to
+return.
+
+@item -mlong-calls
+@itemx -mno-long-calls
+@opindex mlong-calls
+@opindex mno-long-calls
+Tells the compiler to perform function calls by first loading the
+address of the function into a register and then performing a subroutine
+call on this register.  This switch is needed if the target function
+will lie outside of the 64 megabyte addressing range of the offset based
+version of subroutine call instruction.
+
+Even if this switch is enabled, not all function calls will be turned
+into long calls.  The heuristic is that static functions, functions
+which have the @samp{short-call} attribute, functions that are inside
+the scope of a @samp{#pragma no_long_calls} directive and functions whose
+definitions have already been compiled within the current compilation
+unit, will not be turned into long calls.  The exception to this rule is
+that weak function definitions, functions with the @samp{long-call}
+attribute or the @samp{section} attribute, and functions that are within
+the scope of a @samp{#pragma long_calls} directive, will always be
+turned into long calls.
+
+This feature is not enabled by default.  Specifying
+@option{-mno-long-calls} will restore the default behavior, as will
+placing the function calls within the scope of a @samp{#pragma
+long_calls_off} directive.  Note these switches have no effect on how
+the compiler generates code to handle function calls via function
+pointers.
+
+@item -mnop-fun-dllimport
+@opindex mnop-fun-dllimport
+Disable support for the @code{dllimport} attribute.
+
+@item -msingle-pic-base
+@opindex msingle-pic-base
+Treat the register used for PIC addressing as read-only, rather than
+loading it in the prologue for each function.  The run-time system is
+responsible for initializing this register with an appropriate value
+before execution begins.
+
+@item -mpic-register=@var{reg}
+@opindex mpic-register
+Specify the register to be used for PIC addressing.  The default is R10
+unless stack-checking is enabled, when R9 is used.
+
+@item -mpoke-function-name
+@opindex mpoke-function-name
+Write the name of each function into the text section, directly
+preceding the function prologue.  The generated code is similar to this:
+
+@smallexample
+     t0
+         .ascii "arm_poke_function_name", 0
+         .align
+     t1
+         .word 0xff000000 + (t1 - t0)
+     arm_poke_function_name
+         mov     ip, sp
+         stmfd   sp!, @{fp, ip, lr, pc@}
+         sub     fp, ip, #4
+@end smallexample
+
+When performing a stack backtrace, code can inspect the value of
+@code{pc} stored at @code{fp + 0}.  If the trace function then looks at
+location @code{pc - 12} and the top 8 bits are set, then we know that
+there is a function name embedded immediately preceding this location
+and has length @code{((pc[-3]) & 0xff000000)}.
+
+@item -mthumb
+@opindex mthumb
+Generate code for the 16-bit Thumb instruction set.  The default is to
+use the 32-bit ARM instruction set.
+
+@item -mtpcs-frame
+@opindex mtpcs-frame
+Generate a stack frame that is compliant with the Thumb Procedure Call
+Standard for all non-leaf functions.  (A leaf function is one that does
+not call any other functions.)  The default is @option{-mno-tpcs-frame}.
+
+@item -mtpcs-leaf-frame
+@opindex mtpcs-leaf-frame
+Generate a stack frame that is compliant with the Thumb Procedure Call
+Standard for all leaf functions.  (A leaf function is one that does
+not call any other functions.)  The default is @option{-mno-apcs-leaf-frame}.
+
+@item -mcallee-super-interworking
+@opindex mcallee-super-interworking
+Gives all externally visible functions in the file being compiled an ARM
+instruction set header which switches to Thumb mode before executing the
+rest of the function.  This allows these functions to be called from
+non-interworking code.
+
+@item -mcaller-super-interworking
+@opindex mcaller-super-interworking
+Allows calls via function pointers (including virtual functions) to
+execute correctly regardless of whether the target code has been
+compiled for interworking or not.  There is a small overhead in the cost
+of executing a function pointer if this option is enabled.
+
+@end table
+
+@node MN10200 Options
+@subsection MN10200 Options
+@cindex MN10200 options
+These @option{-m} options are defined for Matsushita MN10200 architectures:
+@table @gcctabopt
+
+@item -mrelax
+@opindex mrelax
+Indicate to the linker that it should perform a relaxation optimization pass
+to shorten branches, calls and absolute memory addresses.  This option only
+has an effect when used on the command line for the final link step.
+
+This option makes symbolic debugging impossible.
+@end table
+
+@node MN10300 Options
+@subsection MN10300 Options
+@cindex MN10300 options
+These @option{-m} options are defined for Matsushita MN10300 architectures:
+
+@table @gcctabopt
+@item -mmult-bug
+@opindex mmult-bug
+Generate code to avoid bugs in the multiply instructions for the MN10300
+processors.  This is the default.
+
+@item -mno-mult-bug
+@opindex mno-mult-bug
+Do not generate code to avoid bugs in the multiply instructions for the
+MN10300 processors.
+
+@item -mam33
+@opindex mam33
+Generate code which uses features specific to the AM33 processor.
+
+@item -mno-am33
+@opindex mno-am33
+Do not generate code which uses features specific to the AM33 processor.  This
+is the default.
+
+@item -mno-crt0
+@opindex mno-crt0
+Do not link in the C run-time initialization object file.
+
+@item -mrelax
+@opindex mrelax
+Indicate to the linker that it should perform a relaxation optimization pass
+to shorten branches, calls and absolute memory addresses.  This option only
+has an effect when used on the command line for the final link step.
+
+This option makes symbolic debugging impossible.
+@end table
+
+
+@node M32R/D Options
+@subsection M32R/D Options
+@cindex M32R/D options
+
+These @option{-m} options are defined for Mitsubishi M32R/D architectures:
+
+@table @gcctabopt
+@item -m32rx
+@opindex m32rx
+Generate code for the M32R/X@.
+
+@item -m32r
+@opindex m32r
+Generate code for the M32R@.  This is the default.
+
+@item -mcode-model=small
+@opindex mcode-model=small
+Assume all objects live in the lower 16MB of memory (so that their addresses
+can be loaded with the @code{ld24} instruction), and assume all subroutines
+are reachable with the @code{bl} instruction.
+This is the default.
+
+The addressability of a particular object can be set with the
+@code{model} attribute.
+
+@item -mcode-model=medium
+@opindex mcode-model=medium
+Assume objects may be anywhere in the 32-bit address space (the compiler
+will generate @code{seth/add3} instructions to load their addresses), and
+assume all subroutines are reachable with the @code{bl} instruction.
+
+@item -mcode-model=large
+@opindex mcode-model=large
+Assume objects may be anywhere in the 32-bit address space (the compiler
+will generate @code{seth/add3} instructions to load their addresses), and
+assume subroutines may not be reachable with the @code{bl} instruction
+(the compiler will generate the much slower @code{seth/add3/jl}
+instruction sequence).
+
+@item -msdata=none
+@opindex msdata=none
+Disable use of the small data area.  Variables will be put into
+one of @samp{.data}, @samp{bss}, or @samp{.rodata} (unless the
+@code{section} attribute has been specified).
+This is the default.
+
+The small data area consists of sections @samp{.sdata} and @samp{.sbss}.
+Objects may be explicitly put in the small data area with the
+@code{section} attribute using one of these sections.
+
+@item -msdata=sdata
+@opindex msdata=sdata
+Put small global and static data in the small data area, but do not
+generate special code to reference them.
+
+@item -msdata=use
+@opindex msdata=use
+Put small global and static data in the small data area, and generate
+special instructions to reference them.
+
+@item -G @var{num}
+@opindex G
+@cindex smaller data references
+Put global and static objects less than or equal to @var{num} bytes
+into the small data or bss sections instead of the normal data or bss
+sections.  The default value of @var{num} is 8.
+The @option{-msdata} option must be set to one of @samp{sdata} or @samp{use}
+for this option to have any effect.
+
+All modules should be compiled with the same @option{-G @var{num}} value.
+Compiling with different values of @var{num} may or may not work; if it
+doesn't the linker will give an error message---incorrect code will not be
+generated.
+
+@end table
+
+@node M88K Options
+@subsection M88K Options
+@cindex M88k options
+
+These @samp{-m} options are defined for Motorola 88k architectures:
+
+@table @gcctabopt
+@item -m88000
+@opindex m88000
+Generate code that works well on both the m88100 and the
+m88110.
+
+@item -m88100
+@opindex m88100
+Generate code that works best for the m88100, but that also
+runs on the m88110.
+
+@item -m88110
+@opindex m88110
+Generate code that works best for the m88110, and may not run
+on the m88100.
+
+@item -mbig-pic
+@opindex mbig-pic
+Obsolete option to be removed from the next revision.
+Use @option{-fPIC}.
+
+@item -midentify-revision
+@opindex midentify-revision
+@cindex identifying source, compiler (88k)
+Include an @code{ident} directive in the assembler output recording the
+source file name, compiler name and version, timestamp, and compilation
+flags used.
+
+@item -mno-underscores
+@opindex mno-underscores
+@cindex underscores, avoiding (88k)
+In assembler output, emit symbol names without adding an underscore
+character at the beginning of each name.  The default is to use an
+underscore as prefix on each name.
+
+@item -mocs-debug-info
+@itemx -mno-ocs-debug-info
+@opindex mocs-debug-info
+@opindex mno-ocs-debug-info
+@cindex OCS (88k)
+@cindex debugging, 88k OCS
+Include (or omit) additional debugging information (about registers used
+in each stack frame) as specified in the 88open Object Compatibility
+Standard, ``OCS''@.  This extra information allows debugging of code that
+has had the frame pointer eliminated.  The default for DG/UX, SVr4, and
+Delta 88 SVr3.2 is to include this information; other 88k configurations
+omit this information by default.
+
+@item -mocs-frame-position
+@opindex mocs-frame-position
+@cindex register positions in frame (88k)
+When emitting COFF debugging information for automatic variables and
+parameters stored on the stack, use the offset from the canonical frame
+address, which is the stack pointer (register 31) on entry to the
+function.  The DG/UX, SVr4, Delta88 SVr3.2, and BCS configurations use
+@option{-mocs-frame-position}; other 88k configurations have the default
+@option{-mno-ocs-frame-position}.
+
+@item -mno-ocs-frame-position
+@opindex mno-ocs-frame-position
+@cindex register positions in frame (88k)
+When emitting COFF debugging information for automatic variables and
+parameters stored on the stack, use the offset from the frame pointer
+register (register 30).  When this option is in effect, the frame
+pointer is not eliminated when debugging information is selected by the
+-g switch.
+
+@item -moptimize-arg-area
+@opindex moptimize-arg-area
+@cindex arguments in frame (88k)
+Save space by reorganizing the stack frame.  This option generates code
+that does not agree with the 88open specifications, but uses less
+memory.
+
+@itemx -mno-optimize-arg-area
+@opindex mno-optimize-arg-area
+Do not reorganize the stack frame to save space.  This is the default.
+The generated conforms to the specification, but uses more memory.
+
+@item -mshort-data-@var{num}
+@opindex mshort-data
+@cindex smaller data references (88k)
+@cindex r0-relative references (88k)
+Generate smaller data references by making them relative to @code{r0},
+which allows loading a value using a single instruction (rather than the
+usual two).  You control which data references are affected by
+specifying @var{num} with this option.  For example, if you specify
+@option{-mshort-data-512}, then the data references affected are those
+involving displacements of less than 512 bytes.
+@option{-mshort-data-@var{num}} is not effective for @var{num} greater
+than 64k.
+
+@item -mserialize-volatile
+@opindex mserialize-volatile
+@itemx -mno-serialize-volatile
+@opindex mno-serialize-volatile
+@cindex sequential consistency on 88k
+Do, or don't, generate code to guarantee sequential consistency
+of volatile memory references.  By default, consistency is
+guaranteed.
+
+The order of memory references made by the MC88110 processor does
+not always match the order of the instructions requesting those
+references.  In particular, a load instruction may execute before
+a preceding store instruction.  Such reordering violates
+sequential consistency of volatile memory references, when there
+are multiple processors.   When consistency must be guaranteed,
+GCC generates special instructions, as needed, to force
+execution in the proper order.
+
+The MC88100 processor does not reorder memory references and so
+always provides sequential consistency.  However, by default, GCC
+generates the special instructions to guarantee consistency
+even when you use @option{-m88100}, so that the code may be run on an
+MC88110 processor.  If you intend to run your code only on the
+MC88100 processor, you may use @option{-mno-serialize-volatile}.
+
+The extra code generated to guarantee consistency may affect the
+performance of your application.  If you know that you can safely
+forgo this guarantee, you may use @option{-mno-serialize-volatile}.
+
+@item -msvr4
+@itemx -msvr3
+@opindex msvr4
+@opindex msvr3
+@cindex assembler syntax, 88k
+@cindex SVr4
+Turn on (@option{-msvr4}) or off (@option{-msvr3}) compiler extensions
+related to System V release 4 (SVr4).  This controls the following:
+
+@enumerate
+@item
+Which variant of the assembler syntax to emit.
+@item
+@option{-msvr4} makes the C preprocessor recognize @samp{#pragma weak}
+that is used on System V release 4.
+@item
+@option{-msvr4} makes GCC issue additional declaration directives used in
+SVr4.
+@end enumerate
+
+@option{-msvr4} is the default for the m88k-motorola-sysv4 and
+m88k-dg-dgux m88k configurations.  @option{-msvr3} is the default for all
+other m88k configurations.
+
+@item -mversion-03.00
+@opindex mversion-03.00
+This option is obsolete, and is ignored.
+@c ??? which asm syntax better for GAS?  option there too?
+
+@item -mno-check-zero-division
+@itemx -mcheck-zero-division
+@opindex mno-check-zero-division
+@opindex mcheck-zero-division
+@cindex zero division on 88k
+Do, or don't, generate code to guarantee that integer division by
+zero will be detected.  By default, detection is guaranteed.
+
+Some models of the MC88100 processor fail to trap upon integer
+division by zero under certain conditions.  By default, when
+compiling code that might be run on such a processor, GCC
+generates code that explicitly checks for zero-valued divisors
+and traps with exception number 503 when one is detected.  Use of
+@option{-mno-check-zero-division} suppresses such checking for code
+generated to run on an MC88100 processor.
+
+GCC assumes that the MC88110 processor correctly detects all instances
+of integer division by zero.  When @option{-m88110} is specified, no
+explicit checks for zero-valued divisors are generated, and both
+@option{-mcheck-zero-division} and @option{-mno-check-zero-division} are
+ignored.
+
+@item -muse-div-instruction
+@opindex muse-div-instruction
+@cindex divide instruction, 88k
+Use the div instruction for signed integer division on the
+MC88100 processor.  By default, the div instruction is not used.
+
+On the MC88100 processor the signed integer division instruction
+div) traps to the operating system on a negative operand.  The
+operating system transparently completes the operation, but at a
+large cost in execution time.  By default, when compiling code
+that might be run on an MC88100 processor, GCC emulates signed
+integer division using the unsigned integer division instruction
+divu), thereby avoiding the large penalty of a trap to the
+operating system.  Such emulation has its own, smaller, execution
+cost in both time and space.  To the extent that your code's
+important signed integer division operations are performed on two
+nonnegative operands, it may be desirable to use the div
+instruction directly.
+
+On the MC88110 processor the div instruction (also known as the
+divs instruction) processes negative operands without trapping to
+the operating system.  When @option{-m88110} is specified,
+@option{-muse-div-instruction} is ignored, and the div instruction is used
+for signed integer division.
+
+Note that the result of dividing @code{INT_MIN} by @minus{}1 is undefined.  In
+particular, the behavior of such a division with and without
+@option{-muse-div-instruction} may differ.
+
+@item -mtrap-large-shift
+@itemx -mhandle-large-shift
+@opindex mtrap-large-shift
+@opindex mhandle-large-shift
+@cindex bit shift overflow (88k)
+@cindex large bit shifts (88k)
+Include code to detect bit-shifts of more than 31 bits; respectively,
+trap such shifts or emit code to handle them properly.  By default GCC
+makes no special provision for large bit shifts.
+
+@item -mwarn-passed-structs
+@opindex mwarn-passed-structs
+@cindex structure passing (88k)
+Warn when a function passes a struct as an argument or result.
+Structure-passing conventions have changed during the evolution of the C
+language, and are often the source of portability problems.  By default,
+GCC issues no such warning.
+@end table
+
+@c break page here to avoid unsightly interparagraph stretch.
+@c -zw, 2001-8-17
+@page
+
+@node RS/6000 and PowerPC Options
+@subsection IBM RS/6000 and PowerPC Options
+@cindex RS/6000 and PowerPC Options
+@cindex IBM RS/6000 and PowerPC Options
+
+These @samp{-m} options are defined for the IBM RS/6000 and PowerPC:
+@table @gcctabopt
+@item -mpower
+@itemx -mno-power
+@itemx -mpower2
+@itemx -mno-power2
+@itemx -mpowerpc
+@itemx -mno-powerpc
+@itemx -mpowerpc-gpopt
+@itemx -mno-powerpc-gpopt
+@itemx -mpowerpc-gfxopt
+@itemx -mno-powerpc-gfxopt
+@itemx -mpowerpc64
+@itemx -mno-powerpc64
+@opindex mpower
+@opindex mno-power
+@opindex mpower2
+@opindex mno-power2
+@opindex mpowerpc
+@opindex mno-powerpc
+@opindex mpowerpc-gpopt
+@opindex mno-powerpc-gpopt
+@opindex mpowerpc-gfxopt
+@opindex mno-powerpc-gfxopt
+@opindex mpowerpc64
+@opindex mno-powerpc64
+GCC supports two related instruction set architectures for the
+RS/6000 and PowerPC@.  The @dfn{POWER} instruction set are those
+instructions supported by the @samp{rios} chip set used in the original
+RS/6000 systems and the @dfn{PowerPC} instruction set is the
+architecture of the Motorola MPC5xx, MPC6xx, MPC8xx microprocessors, and
+the IBM 4xx microprocessors.
+
+Neither architecture is a subset of the other.  However there is a
+large common subset of instructions supported by both.  An MQ
+register is included in processors supporting the POWER architecture.
+
+You use these options to specify which instructions are available on the
+processor you are using.  The default value of these options is
+determined when configuring GCC@.  Specifying the
+@option{-mcpu=@var{cpu_type}} overrides the specification of these
+options.  We recommend you use the @option{-mcpu=@var{cpu_type}} option
+rather than the options listed above.
+
+The @option{-mpower} option allows GCC to generate instructions that
+are found only in the POWER architecture and to use the MQ register.
+Specifying @option{-mpower2} implies @option{-power} and also allows GCC
+to generate instructions that are present in the POWER2 architecture but
+not the original POWER architecture.
+
+The @option{-mpowerpc} option allows GCC to generate instructions that
+are found only in the 32-bit subset of the PowerPC architecture.
+Specifying @option{-mpowerpc-gpopt} implies @option{-mpowerpc} and also allows
+GCC to use the optional PowerPC architecture instructions in the
+General Purpose group, including floating-point square root.  Specifying
+@option{-mpowerpc-gfxopt} implies @option{-mpowerpc} and also allows GCC to
+use the optional PowerPC architecture instructions in the Graphics
+group, including floating-point select.
+
+The @option{-mpowerpc64} option allows GCC to generate the additional
+64-bit instructions that are found in the full PowerPC64 architecture
+and to treat GPRs as 64-bit, doubleword quantities.  GCC defaults to
+@option{-mno-powerpc64}.
+
+If you specify both @option{-mno-power} and @option{-mno-powerpc}, GCC
+will use only the instructions in the common subset of both
+architectures plus some special AIX common-mode calls, and will not use
+the MQ register.  Specifying both @option{-mpower} and @option{-mpowerpc}
+permits GCC to use any instruction from either architecture and to
+allow use of the MQ register; specify this for the Motorola MPC601.
+
+@item -mnew-mnemonics
+@itemx -mold-mnemonics
+@opindex mnew-mnemonics
+@opindex mold-mnemonics
+Select which mnemonics to use in the generated assembler code.  With
+@option{-mnew-mnemonics}, GCC uses the assembler mnemonics defined for
+the PowerPC architecture.  With @option{-mold-mnemonics} it uses the
+assembler mnemonics defined for the POWER architecture.  Instructions
+defined in only one architecture have only one mnemonic; GCC uses that
+mnemonic irrespective of which of these options is specified.
+
+GCC defaults to the mnemonics appropriate for the architecture in
+use.  Specifying @option{-mcpu=@var{cpu_type}} sometimes overrides the
+value of these option.  Unless you are building a cross-compiler, you
+should normally not specify either @option{-mnew-mnemonics} or
+@option{-mold-mnemonics}, but should instead accept the default.
+
+@item -mcpu=@var{cpu_type}
+@opindex mcpu
+Set architecture type, register usage, choice of mnemonics, and
+instruction scheduling parameters for machine type @var{cpu_type}.
+Supported values for @var{cpu_type} are @samp{rios}, @samp{rios1},
+@samp{rsc}, @samp{rios2}, @samp{rs64a}, @samp{601}, @samp{602},
+@samp{603}, @samp{603e}, @samp{604}, @samp{604e}, @samp{620},
+@samp{630}, @samp{740}, @samp{7400}, @samp{7450}, @samp{750},
+@samp{power}, @samp{power2}, @samp{powerpc}, @samp{403}, @samp{505},
+@samp{801}, @samp{821}, @samp{823}, and @samp{860} and @samp{common}.
+
+@option{-mcpu=common} selects a completely generic processor.  Code
+generated under this option will run on any POWER or PowerPC processor.
+GCC will use only the instructions in the common subset of both
+architectures, and will not use the MQ register.  GCC assumes a generic
+processor model for scheduling purposes.
+
+@option{-mcpu=power}, @option{-mcpu=power2}, @option{-mcpu=powerpc}, and
+@option{-mcpu=powerpc64} specify generic POWER, POWER2, pure 32-bit
+PowerPC (i.e., not MPC601), and 64-bit PowerPC architecture machine
+types, with an appropriate, generic processor model assumed for
+scheduling purposes.
+
+The other options specify a specific processor.  Code generated under
+those options will run best on that processor, and may not run at all on
+others.
+
+The @option{-mcpu} options automatically enable or disable other
+@option{-m} options as follows:
+
+@table @samp
+@item common
+@option{-mno-power}, @option{-mno-powerc}
+
+@item power
+@itemx power2
+@itemx rios1
+@itemx rios2
+@itemx rsc
+@option{-mpower}, @option{-mno-powerpc}, @option{-mno-new-mnemonics}
+
+@item powerpc
+@itemx rs64a
+@itemx 602
+@itemx 603
+@itemx 603e
+@itemx 604
+@itemx 620
+@itemx 630
+@itemx 740
+@itemx 7400
+@itemx 7450
+@itemx 750
+@itemx 505
+@option{-mno-power}, @option{-mpowerpc}, @option{-mnew-mnemonics}
+
+@item 601
+@option{-mpower}, @option{-mpowerpc}, @option{-mnew-mnemonics}
+
+@item 403
+@itemx 821
+@itemx 860
+@option{-mno-power}, @option{-mpowerpc}, @option{-mnew-mnemonics}, @option{-msoft-float}
+@end table
+
+@item -mtune=@var{cpu_type}
+@opindex mtune
+Set the instruction scheduling parameters for machine type
+@var{cpu_type}, but do not set the architecture type, register usage, or
+choice of mnemonics, as @option{-mcpu=@var{cpu_type}} would.  The same
+values for @var{cpu_type} are used for @option{-mtune} as for
+@option{-mcpu}.  If both are specified, the code generated will use the
+architecture, registers, and mnemonics set by @option{-mcpu}, but the
+scheduling parameters set by @option{-mtune}.
+
+@item -maltivec
+@itemx -mno-altivec
+@opindex maltivec
+@opindex mno-altivec
+These switches enable or disable the use of built-in functions that
+allow access to the AltiVec instruction set.  You may also need to set
+@option{-mabi=altivec} to adjust the current ABI with AltiVec ABI
+enhancements.
+
+@item -mfull-toc
+@itemx -mno-fp-in-toc
+@itemx -mno-sum-in-toc
+@itemx -mminimal-toc
+@opindex mfull-toc
+@opindex mno-fp-in-toc
+@opindex mno-sum-in-toc
+@opindex mminimal-toc
+Modify generation of the TOC (Table Of Contents), which is created for
+every executable file.  The @option{-mfull-toc} option is selected by
+default.  In that case, GCC will allocate at least one TOC entry for
+each unique non-automatic variable reference in your program.  GCC
+will also place floating-point constants in the TOC@.  However, only
+16,384 entries are available in the TOC@.
+
+If you receive a linker error message that saying you have overflowed
+the available TOC space, you can reduce the amount of TOC space used
+with the @option{-mno-fp-in-toc} and @option{-mno-sum-in-toc} options.
+@option{-mno-fp-in-toc} prevents GCC from putting floating-point
+constants in the TOC and @option{-mno-sum-in-toc} forces GCC to
+generate code to calculate the sum of an address and a constant at
+run-time instead of putting that sum into the TOC@.  You may specify one
+or both of these options.  Each causes GCC to produce very slightly
+slower and larger code at the expense of conserving TOC space.
+
+If you still run out of space in the TOC even when you specify both of
+these options, specify @option{-mminimal-toc} instead.  This option causes
+GCC to make only one TOC entry for every file.  When you specify this
+option, GCC will produce code that is slower and larger but which
+uses extremely little TOC space.  You may wish to use this option
+only on files that contain less frequently executed code.
+
+@item -maix64
+@itemx -maix32
+@opindex maix64
+@opindex maix32
+Enable 64-bit AIX ABI and calling convention: 64-bit pointers, 64-bit
+@code{long} type, and the infrastructure needed to support them.
+Specifying @option{-maix64} implies @option{-mpowerpc64} and
+@option{-mpowerpc}, while @option{-maix32} disables the 64-bit ABI and
+implies @option{-mno-powerpc64}.  GCC defaults to @option{-maix32}.
+
+@item -mxl-call
+@itemx -mno-xl-call
+@opindex mxl-call
+@opindex mno-xl-call
+On AIX, pass floating-point arguments to prototyped functions beyond the
+register save area (RSA) on the stack in addition to argument FPRs.  The
+AIX calling convention was extended but not initially documented to
+handle an obscure K&R C case of calling a function that takes the
+address of its arguments with fewer arguments than declared.  AIX XL
+compilers access floating point arguments which do not fit in the
+RSA from the stack when a subroutine is compiled without
+optimization.  Because always storing floating-point arguments on the
+stack is inefficient and rarely needed, this option is not enabled by
+default and only is necessary when calling subroutines compiled by AIX
+XL compilers without optimization.
+
+@item -mpe
+@opindex mpe
+Support @dfn{IBM RS/6000 SP} @dfn{Parallel Environment} (PE)@.  Link an
+application written to use message passing with special startup code to
+enable the application to run.  The system must have PE installed in the
+standard location (@file{/usr/lpp/ppe.poe/}), or the @file{specs} file
+must be overridden with the @option{-specs=} option to specify the
+appropriate directory location.  The Parallel Environment does not
+support threads, so the @option{-mpe} option and the @option{-pthread}
+option are incompatible.
+
+@item -msoft-float
+@itemx -mhard-float
+@opindex msoft-float
+@opindex mhard-float
+Generate code that does not use (uses) the floating-point register set.
+Software floating point emulation is provided if you use the
+@option{-msoft-float} option, and pass the option to GCC when linking.
+
+@item -mmultiple
+@itemx -mno-multiple
+@opindex mmultiple
+@opindex mno-multiple
+Generate code that uses (does not use) the load multiple word
+instructions and the store multiple word instructions.  These
+instructions are generated by default on POWER systems, and not
+generated on PowerPC systems.  Do not use @option{-mmultiple} on little
+endian PowerPC systems, since those instructions do not work when the
+processor is in little endian mode.  The exceptions are PPC740 and
+PPC750 which permit the instructions usage in little endian mode.
+
+@item -mstring
+@itemx -mno-string
+@opindex mstring
+@opindex mno-string
+Generate code that uses (does not use) the load string instructions
+and the store string word instructions to save multiple registers and
+do small block moves.  These instructions are generated by default on
+POWER systems, and not generated on PowerPC systems.  Do not use
+@option{-mstring} on little endian PowerPC systems, since those
+instructions do not work when the processor is in little endian mode.
+The exceptions are PPC740 and PPC750 which permit the instructions
+usage in little endian mode.
+
+@item -mupdate
+@itemx -mno-update
+@opindex mupdate
+@opindex mno-update
+Generate code that uses (does not use) the load or store instructions
+that update the base register to the address of the calculated memory
+location.  These instructions are generated by default.  If you use
+@option{-mno-update}, there is a small window between the time that the
+stack pointer is updated and the address of the previous frame is
+stored, which means code that walks the stack frame across interrupts or
+signals may get corrupted data.
+
+@item -mfused-madd
+@itemx -mno-fused-madd
+@opindex mfused-madd
+@opindex mno-fused-madd
+Generate code that uses (does not use) the floating point multiply and
+accumulate instructions.  These instructions are generated by default if
+hardware floating is used.
+
+@item -mno-bit-align
+@itemx -mbit-align
+@opindex mno-bit-align
+@opindex mbit-align
+On System V.4 and embedded PowerPC systems do not (do) force structures
+and unions that contain bit-fields to be aligned to the base type of the
+bit-field.
+
+For example, by default a structure containing nothing but 8
+@code{unsigned} bit-fields of length 1 would be aligned to a 4 byte
+boundary and have a size of 4 bytes.  By using @option{-mno-bit-align},
+the structure would be aligned to a 1 byte boundary and be one byte in
+size.
+
+@item -mno-strict-align
+@itemx -mstrict-align
+@opindex mno-strict-align
+@opindex mstrict-align
+On System V.4 and embedded PowerPC systems do not (do) assume that
+unaligned memory references will be handled by the system.
+
+@item -mrelocatable
+@itemx -mno-relocatable
+@opindex mrelocatable
+@opindex mno-relocatable
+On embedded PowerPC systems generate code that allows (does not allow)
+the program to be relocated to a different address at runtime.  If you
+use @option{-mrelocatable} on any module, all objects linked together must
+be compiled with @option{-mrelocatable} or @option{-mrelocatable-lib}.
+
+@item -mrelocatable-lib
+@itemx -mno-relocatable-lib
+@opindex mrelocatable-lib
+@opindex mno-relocatable-lib
+On embedded PowerPC systems generate code that allows (does not allow)
+the program to be relocated to a different address at runtime.  Modules
+compiled with @option{-mrelocatable-lib} can be linked with either modules
+compiled without @option{-mrelocatable} and @option{-mrelocatable-lib} or
+with modules compiled with the @option{-mrelocatable} options.
+
+@item -mno-toc
+@itemx -mtoc
+@opindex mno-toc
+@opindex mtoc
+On System V.4 and embedded PowerPC systems do not (do) assume that
+register 2 contains a pointer to a global area pointing to the addresses
+used in the program.
+
+@item -mlittle
+@itemx -mlittle-endian
+@opindex mlittle
+@opindex mlittle-endian
+On System V.4 and embedded PowerPC systems compile code for the
+processor in little endian mode.  The @option{-mlittle-endian} option is
+the same as @option{-mlittle}.
+
+@item -mbig
+@itemx -mbig-endian
+@opindex mbig
+@opindex mbig-endian
+On System V.4 and embedded PowerPC systems compile code for the
+processor in big endian mode.  The @option{-mbig-endian} option is
+the same as @option{-mbig}.
+
+@item -mcall-sysv
+@opindex mcall-sysv
+On System V.4 and embedded PowerPC systems compile code using calling
+conventions that adheres to the March 1995 draft of the System V
+Application Binary Interface, PowerPC processor supplement.  This is the
+default unless you configured GCC using @samp{powerpc-*-eabiaix}.
+
+@item -mcall-sysv-eabi
+@opindex mcall-sysv-eabi
+Specify both @option{-mcall-sysv} and @option{-meabi} options.
+
+@item -mcall-sysv-noeabi
+@opindex mcall-sysv-noeabi
+Specify both @option{-mcall-sysv} and @option{-mno-eabi} options.
+
+@item -mcall-aix
+@opindex mcall-aix
+On System V.4 and embedded PowerPC systems compile code using calling
+conventions that are similar to those used on AIX@.  This is the
+default if you configured GCC using @samp{powerpc-*-eabiaix}.
+
+@item -mcall-solaris
+@opindex mcall-solaris
+On System V.4 and embedded PowerPC systems compile code for the Solaris
+operating system.
+
+@item -mcall-linux
+@opindex mcall-linux
+On System V.4 and embedded PowerPC systems compile code for the
+Linux-based GNU system.
+
+@item -mcall-gnu
+@opindex mcall-gnu
+On System V.4 and embedded PowerPC systems compile code for the
+Hurd-based GNU system.
+
+@item -mcall-netbsd
+@opindex mcall-netbsd
+On System V.4 and embedded PowerPC systems compile code for the
+NetBSD operating system.
+
+@item -maix-struct-return
+@opindex maix-struct-return
+Return all structures in memory (as specified by the AIX ABI)@.
+
+@item -msvr4-struct-return
+@opindex msvr4-struct-return
+Return structures smaller than 8 bytes in registers (as specified by the
+SVR4 ABI)@.
+
+@item -mabi=altivec
+@opindex mabi=altivec
+Extend the current ABI with AltiVec ABI extensions.  This does not
+change the default ABI, instead it adds the AltiVec ABI extensions to
+the current ABI@.
+
+@item -mprototype
+@itemx -mno-prototype
+@opindex mprototype
+@opindex mno-prototype
+On System V.4 and embedded PowerPC systems assume that all calls to
+variable argument functions are properly prototyped.  Otherwise, the
+compiler must insert an instruction before every non prototyped call to
+set or clear bit 6 of the condition code register (@var{CR}) to
+indicate whether floating point values were passed in the floating point
+registers in case the function takes a variable arguments.  With
+@option{-mprototype}, only calls to prototyped variable argument functions
+will set or clear the bit.
+
+@item -msim
+@opindex msim
+On embedded PowerPC systems, assume that the startup module is called
+@file{sim-crt0.o} and that the standard C libraries are @file{libsim.a} and
+@file{libc.a}.  This is the default for @samp{powerpc-*-eabisim}.
+configurations.
+
+@item -mmvme
+@opindex mmvme
+On embedded PowerPC systems, assume that the startup module is called
+@file{crt0.o} and the standard C libraries are @file{libmvme.a} and
+@file{libc.a}.
+
+@item -mads
+@opindex mads
+On embedded PowerPC systems, assume that the startup module is called
+@file{crt0.o} and the standard C libraries are @file{libads.a} and
+@file{libc.a}.
+
+@item -myellowknife
+@opindex myellowknife
+On embedded PowerPC systems, assume that the startup module is called
+@file{crt0.o} and the standard C libraries are @file{libyk.a} and
+@file{libc.a}.
+
+@item -mvxworks
+@opindex mvxworks
+On System V.4 and embedded PowerPC systems, specify that you are
+compiling for a VxWorks system.
+
+@item -memb
+@opindex memb
+On embedded PowerPC systems, set the @var{PPC_EMB} bit in the ELF flags
+header to indicate that @samp{eabi} extended relocations are used.
+
+@item -meabi
+@itemx -mno-eabi
+@opindex meabi
+@opindex mno-eabi
+On System V.4 and embedded PowerPC systems do (do not) adhere to the
+Embedded Applications Binary Interface (eabi) which is a set of
+modifications to the System V.4 specifications.  Selecting @option{-meabi}
+means that the stack is aligned to an 8 byte boundary, a function
+@code{__eabi} is called to from @code{main} to set up the eabi
+environment, and the @option{-msdata} option can use both @code{r2} and
+@code{r13} to point to two separate small data areas.  Selecting
+@option{-mno-eabi} means that the stack is aligned to a 16 byte boundary,
+do not call an initialization function from @code{main}, and the
+@option{-msdata} option will only use @code{r13} to point to a single
+small data area.  The @option{-meabi} option is on by default if you
+configured GCC using one of the @samp{powerpc*-*-eabi*} options.
+
+@item -msdata=eabi
+@opindex msdata=eabi
+On System V.4 and embedded PowerPC systems, put small initialized
+@code{const} global and static data in the @samp{.sdata2} section, which
+is pointed to by register @code{r2}.  Put small initialized
+non-@code{const} global and static data in the @samp{.sdata} section,
+which is pointed to by register @code{r13}.  Put small uninitialized
+global and static data in the @samp{.sbss} section, which is adjacent to
+the @samp{.sdata} section.  The @option{-msdata=eabi} option is
+incompatible with the @option{-mrelocatable} option.  The
+@option{-msdata=eabi} option also sets the @option{-memb} option.
+
+@item -msdata=sysv
+@opindex msdata=sysv
+On System V.4 and embedded PowerPC systems, put small global and static
+data in the @samp{.sdata} section, which is pointed to by register
+@code{r13}.  Put small uninitialized global and static data in the
+@samp{.sbss} section, which is adjacent to the @samp{.sdata} section.
+The @option{-msdata=sysv} option is incompatible with the
+@option{-mrelocatable} option.
+
+@item -msdata=default
+@itemx -msdata
+@opindex msdata=default
+@opindex msdata
+On System V.4 and embedded PowerPC systems, if @option{-meabi} is used,
+compile code the same as @option{-msdata=eabi}, otherwise compile code the
+same as @option{-msdata=sysv}.
+
+@item -msdata-data
+@opindex msdata-data
+On System V.4 and embedded PowerPC systems, put small global and static
+data in the @samp{.sdata} section.  Put small uninitialized global and
+static data in the @samp{.sbss} section.  Do not use register @code{r13}
+to address small data however.  This is the default behavior unless
+other @option{-msdata} options are used.
+
+@item -msdata=none
+@itemx -mno-sdata
+@opindex msdata=none
+@opindex mno-sdata
+On embedded PowerPC systems, put all initialized global and static data
+in the @samp{.data} section, and all uninitialized data in the
+@samp{.bss} section.
+
+@item -G @var{num}
+@opindex G
+@cindex smaller data references (PowerPC)
+@cindex .sdata/.sdata2 references (PowerPC)
+On embedded PowerPC systems, put global and static items less than or
+equal to @var{num} bytes into the small data or bss sections instead of
+the normal data or bss section.  By default, @var{num} is 8.  The
+@option{-G @var{num}} switch is also passed to the linker.
+All modules should be compiled with the same @option{-G @var{num}} value.
+
+@item -mregnames
+@itemx -mno-regnames
+@opindex mregnames
+@opindex mno-regnames
+On System V.4 and embedded PowerPC systems do (do not) emit register
+names in the assembly language output using symbolic forms.
+
+@item -pthread
+@opindex pthread
+Adds support for multithreading with the @dfn{pthreads} library.
+This option sets flags for both the preprocessor and linker.
+
+@end table
+
+@node RT Options
+@subsection IBM RT Options
+@cindex RT options
+@cindex IBM RT options
+
+These @samp{-m} options are defined for the IBM RT PC:
+
+@table @gcctabopt
+@item -min-line-mul
+@opindex min-line-mul
+Use an in-line code sequence for integer multiplies.  This is the
+default.
+
+@item -mcall-lib-mul
+@opindex mcall-lib-mul
+Call @code{lmul$$} for integer multiples.
+
+@item -mfull-fp-blocks
+@opindex mfull-fp-blocks
+Generate full-size floating point data blocks, including the minimum
+amount of scratch space recommended by IBM@.  This is the default.
+
+@item -mminimum-fp-blocks
+@opindex mminimum-fp-blocks
+Do not include extra scratch space in floating point data blocks.  This
+results in smaller code, but slower execution, since scratch space must
+be allocated dynamically.
+
+@cindex @file{varargs.h} and RT PC
+@cindex @file{stdarg.h} and RT PC
+@item -mfp-arg-in-fpregs
+@opindex mfp-arg-in-fpregs
+Use a calling sequence incompatible with the IBM calling convention in
+which floating point arguments are passed in floating point registers.
+Note that @code{varargs.h} and @code{stdarg.h} will not work with
+floating point operands if this option is specified.
+
+@item -mfp-arg-in-gregs
+@opindex mfp-arg-in-gregs
+Use the normal calling convention for floating point arguments.  This is
+the default.
+
+@item -mhc-struct-return
+@opindex mhc-struct-return
+Return structures of more than one word in memory, rather than in a
+register.  This provides compatibility with the MetaWare HighC (hc)
+compiler.  Use the option @option{-fpcc-struct-return} for compatibility
+with the Portable C Compiler (pcc).
+
+@item -mnohc-struct-return
+@opindex mnohc-struct-return
+Return some structures of more than one word in registers, when
+convenient.  This is the default.  For compatibility with the
+IBM-supplied compilers, use the option @option{-fpcc-struct-return} or the
+option @option{-mhc-struct-return}.
+@end table
+
+@node MIPS Options
+@subsection MIPS Options
+@cindex MIPS options
+
+These @samp{-m} options are defined for the MIPS family of computers:
+
+@table @gcctabopt
+
+@item -march=@var{cpu-type}
+@opindex march
+Assume the defaults for the machine type @var{cpu-type} when generating
+instructions.  The choices for @var{cpu-type} are  @samp{r2000}, @samp{r3000},
+@samp{r3900}, @samp{r4000}, @samp{r4100}, @samp{r4300}, @samp{r4400},
+@samp{r4600}, @samp{r4650}, @samp{r5000}, @samp{r6000}, @samp{r8000},
+and @samp{orion}.  Additionally, the @samp{r2000}, @samp{r3000},
+@samp{r4000}, @samp{r5000}, and @samp{r6000} can be abbreviated as
+@samp{r2k} (or @samp{r2K}), @samp{r3k}, etc.
+
+@item -mtune=@var{cpu-type}
+@opindex mtune
+Assume the defaults for the machine type @var{cpu-type} when scheduling
+instructions.  The choices for @var{cpu-type} are @samp{r2000}, @samp{r3000},
+@samp{r3900}, @samp{r4000}, @samp{r4100}, @samp{r4300}, @samp{r4400},
+@samp{r4600}, @samp{r4650}, @samp{r5000}, @samp{r6000}, @samp{r8000},
+and @samp{orion}.  Additionally, the @samp{r2000}, @samp{r3000},
+@samp{r4000}, @samp{r5000}, and @samp{r6000} can be abbreviated as
+@samp{r2k} (or @samp{r2K}), @samp{r3k}, etc.  While picking a specific
+@var{cpu-type} will schedule things appropriately for that particular
+chip, the compiler will not generate any code that does not meet level 1
+of the MIPS ISA (instruction set architecture) without a @option{-mipsX}
+or @option{-mabi} switch being used.
+
+@item -mcpu=@var{cpu-type}
+@opindex mcpu
+This is identical to specifying both @option{-march} and @option{-mtune}.
+
+@item -mips1
+@opindex mips1
+Issue instructions from level 1 of the MIPS ISA@.  This is the default.
+@samp{r3000} is the default @var{cpu-type} at this ISA level.
+
+@item -mips2
+@opindex mips2
+Issue instructions from level 2 of the MIPS ISA (branch likely, square
+root instructions).  @samp{r6000} is the default @var{cpu-type} at this
+ISA level.
+
+@item -mips3
+@opindex mips3
+Issue instructions from level 3 of the MIPS ISA (64-bit instructions).
+@samp{r4000} is the default @var{cpu-type} at this ISA level.
+
+@item -mips4
+@opindex mips4
+Issue instructions from level 4 of the MIPS ISA (conditional move,
+prefetch, enhanced FPU instructions).  @samp{r8000} is the default
+@var{cpu-type} at this ISA level.
+
+@item -mfp32
+@opindex mfp32
+Assume that 32 32-bit floating point registers are available.  This is
+the default.
+
+@item -mfp64
+@opindex mfp64
+Assume that 32 64-bit floating point registers are available.  This is
+the default when the @option{-mips3} option is used.
+
+@item -mfused-madd
+@itemx -mno-fused-madd
+@opindex mfused-madd
+@opindex mno-fused-madd
+Generate code that uses (does not use) the floating point multiply and
+accumulate instructions, when they are available.  These instructions
+are generated by default if they are available, but this may be
+undesirable if the extra precision causes problems or on certain chips
+in the mode where denormals are rounded to zero where denormals
+generated by multiply and accumulate instructions cause exceptions
+anyway.
+
+@item -mgp32
+@opindex mgp32
+Assume that 32 32-bit general purpose registers are available.  This is
+the default.
+
+@item -mgp64
+@opindex mgp64
+Assume that 32 64-bit general purpose registers are available.  This is
+the default when the @option{-mips3} option is used.
+
+@item -mint64
+@opindex mint64
+Force int and long types to be 64 bits wide.  See @option{-mlong32} for an
+explanation of the default, and the width of pointers.
+
+@item -mlong64
+@opindex mlong64
+Force long types to be 64 bits wide.  See @option{-mlong32} for an
+explanation of the default, and the width of pointers.
+
+@item -mlong32
+@opindex mlong32
+Force long, int, and pointer types to be 32 bits wide.
+
+If none of @option{-mlong32}, @option{-mlong64}, or @option{-mint64} are set,
+the size of ints, longs, and pointers depends on the ABI and ISA chosen.
+For @option{-mabi=32}, and @option{-mabi=n32}, ints and longs are 32 bits
+wide.  For @option{-mabi=64}, ints are 32 bits, and longs are 64 bits wide.
+For @option{-mabi=eabi} and either @option{-mips1} or @option{-mips2}, ints
+and longs are 32 bits wide.  For @option{-mabi=eabi} and higher ISAs, ints
+are 32 bits, and longs are 64 bits wide.  The width of pointer types is
+the smaller of the width of longs or the width of general purpose
+registers (which in turn depends on the ISA)@.
+
+@item -mabi=32
+@itemx -mabi=o64
+@itemx -mabi=n32
+@itemx -mabi=64
+@itemx -mabi=eabi
+@opindex mabi=32
+@opindex mabi=o64
+@opindex mabi=n32
+@opindex mabi=64
+@opindex mabi=eabi
+Generate code for the indicated ABI@.  The default instruction level is
+@option{-mips1} for @samp{32}, @option{-mips3} for @samp{n32}, and
+@option{-mips4} otherwise.  Conversely, with @option{-mips1} or
+@option{-mips2}, the default ABI is @samp{32}; otherwise, the default ABI
+is @samp{64}.
+
+@item -mmips-as
+@opindex mmips-as
+Generate code for the MIPS assembler, and invoke @file{mips-tfile} to
+add normal debug information.  This is the default for all
+platforms except for the OSF/1 reference platform, using the OSF/rose
+object format.  If the either of the @option{-gstabs} or @option{-gstabs+}
+switches are used, the @file{mips-tfile} program will encapsulate the
+stabs within MIPS ECOFF@.
+
+@item -mgas
+@opindex mgas
+Generate code for the GNU assembler.  This is the default on the OSF/1
+reference platform, using the OSF/rose object format.  Also, this is
+the default if the configure option @option{--with-gnu-as} is used.
+
+@item -msplit-addresses
+@itemx -mno-split-addresses
+@opindex msplit-addresses
+@opindex mno-split-addresses
+Generate code to load the high and low parts of address constants separately.
+This allows GCC to optimize away redundant loads of the high order
+bits of addresses.  This optimization requires GNU as and GNU ld.
+This optimization is enabled by default for some embedded targets where
+GNU as and GNU ld are standard.
+
+@item -mrnames
+@itemx -mno-rnames
+@opindex mrnames
+@opindex mno-rnames
+The @option{-mrnames} switch says to output code using the MIPS software
+names for the registers, instead of the hardware names (ie, @var{a0}
+instead of @var{$4}).  The only known assembler that supports this option
+is the Algorithmics assembler.
+
+@item -mgpopt
+@itemx -mno-gpopt
+@opindex mgpopt
+@opindex mno-gpopt
+The @option{-mgpopt} switch says to write all of the data declarations
+before the instructions in the text section, this allows the MIPS
+assembler to generate one word memory references instead of using two
+words for short global or static data items.  This is on by default if
+optimization is selected.
+
+@item -mstats
+@itemx -mno-stats
+@opindex mstats
+@opindex mno-stats
+For each non-inline function processed, the @option{-mstats} switch
+causes the compiler to emit one line to the standard error file to
+print statistics about the program (number of registers saved, stack
+size, etc.).
+
+@item -mmemcpy
+@itemx -mno-memcpy
+@opindex mmemcpy
+@opindex mno-memcpy
+The @option{-mmemcpy} switch makes all block moves call the appropriate
+string function (@samp{memcpy} or @samp{bcopy}) instead of possibly
+generating inline code.
+
+@item -mmips-tfile
+@itemx -mno-mips-tfile
+@opindex mmips-tfile
+@opindex mno-mips-tfile
+The @option{-mno-mips-tfile} switch causes the compiler not
+postprocess the object file with the @file{mips-tfile} program,
+after the MIPS assembler has generated it to add debug support.  If
+@file{mips-tfile} is not run, then no local variables will be
+available to the debugger.  In addition, @file{stage2} and
+@file{stage3} objects will have the temporary file names passed to the
+assembler embedded in the object file, which means the objects will
+not compare the same.  The @option{-mno-mips-tfile} switch should only
+be used when there are bugs in the @file{mips-tfile} program that
+prevents compilation.
+
+@item -msoft-float
+@opindex msoft-float
+Generate output containing library calls for floating point.
+@strong{Warning:} the requisite libraries are not part of GCC@.
+Normally the facilities of the machine's usual C compiler are used, but
+this can't be done directly in cross-compilation.  You must make your
+own arrangements to provide suitable library functions for
+cross-compilation.
+
+@item -mhard-float
+@opindex mhard-float
+Generate output containing floating point instructions.  This is the
+default if you use the unmodified sources.
+
+@item -mabicalls
+@itemx -mno-abicalls
+@opindex mabicalls
+@opindex mno-abicalls
+Emit (or do not emit) the pseudo operations @samp{.abicalls},
+@samp{.cpload}, and @samp{.cprestore} that some System V.4 ports use for
+position independent code.
+
+@item -mlong-calls
+@itemx -mno-long-calls
+@opindex mlong-calls
+@opindex mno-long-calls
+Do all calls with the @samp{JALR} instruction, which requires
+loading up a function's address into a register before the call.
+You need to use this switch, if you call outside of the current
+512 megabyte segment to functions that are not through pointers.
+
+@item -mhalf-pic
+@itemx -mno-half-pic
+@opindex mhalf-pic
+@opindex mno-half-pic
+Put pointers to extern references into the data section and load them
+up, rather than put the references in the text section.
+
+@item -membedded-pic
+@itemx -mno-embedded-pic
+@opindex membedded-pic
+@opindex mno-embedded-pic
+Generate PIC code suitable for some embedded systems.  All calls are
+made using PC relative address, and all data is addressed using the $gp
+register.  No more than 65536 bytes of global data may be used.  This
+requires GNU as and GNU ld which do most of the work.  This currently
+only works on targets which use ECOFF; it does not work with ELF@.
+
+@item -membedded-data
+@itemx -mno-embedded-data
+@opindex membedded-data
+@opindex mno-embedded-data
+Allocate variables to the read-only data section first if possible, then
+next in the small data section if possible, otherwise in data.  This gives
+slightly slower code than the default, but reduces the amount of RAM required
+when executing, and thus may be preferred for some embedded systems.
+
+@item -muninit-const-in-rodata
+@itemx -mno-uninit-const-in-rodata
+@opindex muninit-const-in-rodata
+@opindex mno-uninit-const-in-rodata
+When used together with @option{-membedded-data}, it will always store uninitialized
+const variables in the read-only data section.
+
+@item -msingle-float
+@itemx -mdouble-float
+@opindex msingle-float
+@opindex mdouble-float
+The @option{-msingle-float} switch tells gcc to assume that the floating
+point coprocessor only supports single precision operations, as on the
+@samp{r4650} chip.  The @option{-mdouble-float} switch permits gcc to use
+double precision operations.  This is the default.
+
+@item -mmad
+@itemx -mno-mad
+@opindex mmad
+@opindex mno-mad
+Permit use of the @samp{mad}, @samp{madu} and @samp{mul} instructions,
+as on the @samp{r4650} chip.
+
+@item -m4650
+@opindex m4650
+Turns on @option{-msingle-float}, @option{-mmad}, and, at least for now,
+@option{-mcpu=r4650}.
+
+@item -mips16
+@itemx -mno-mips16
+@opindex mips16
+@opindex mno-mips16
+Enable 16-bit instructions.
+
+@item -mentry
+@opindex mentry
+Use the entry and exit pseudo ops.  This option can only be used with
+@option{-mips16}.
+
+@item -EL
+@opindex EL
+Compile code for the processor in little endian mode.
+The requisite libraries are assumed to exist.
+
+@item -EB
+@opindex EB
+Compile code for the processor in big endian mode.
+The requisite libraries are assumed to exist.
+
+@item -G @var{num}
+@opindex G
+@cindex smaller data references (MIPS)
+@cindex gp-relative references (MIPS)
+Put global and static items less than or equal to @var{num} bytes into
+the small data or bss sections instead of the normal data or bss
+section.  This allows the assembler to emit one word memory reference
+instructions based on the global pointer (@var{gp} or @var{$28}),
+instead of the normal two words used.  By default, @var{num} is 8 when
+the MIPS assembler is used, and 0 when the GNU assembler is used.  The
+@option{-G @var{num}} switch is also passed to the assembler and linker.
+All modules should be compiled with the same @option{-G @var{num}}
+value.
+
+@item -nocpp
+@opindex nocpp
+Tell the MIPS assembler to not run its preprocessor over user
+assembler files (with a @samp{.s} suffix) when assembling them.
+
+@item -mfix7000
+@opindex mfix7000
+Pass an option to gas which will cause nops to be inserted if
+the read of the destination register of an mfhi or mflo instruction
+occurs in the following two instructions.
+
+@item -no-crt0
+@opindex no-crt0
+Do not include the default crt0.
+
+@item -mflush-func=@var{func}
+@itemx -mno-flush-func
+@opindex mflush-func
+Specifies the function to call to flush the I and D caches, or to not
+call any such function.  If called, the function must take the same
+arguments as the common @code{_flush_func()}, that is, the address of the
+memory range for which the cache is being flushed, the size of the
+memory range, and the number 3 (to flush both caches).  The default
+depends on the target gcc was configured for, but commonly is either
+@samp{_flush_func} or @samp{__cpu_flush}.
+@end table
+
+These options are defined by the macro
+@code{TARGET_SWITCHES} in the machine description.  The default for the
+options is also defined by that macro, which enables you to change the
+defaults.
+
+@node i386 and x86-64 Options
+@subsection Intel 386 and AMD x86-64 Options
+@cindex i386 Options
+@cindex x86-64 Options
+@cindex Intel 386 Options
+@cindex AMD x86-64 Options
+
+These @samp{-m} options are defined for the i386 and x86-64 family of
+computers:
+
+@table @gcctabopt
+@item -mcpu=@var{cpu-type}
+@opindex mcpu
+Tune to @var{cpu-type} everything applicable about the generated code, except
+for the ABI and the set of available instructions.  The choices for
+@var{cpu-type} are @samp{i386}, @samp{i486}, @samp{i586}, @samp{i686},
+@samp{pentium}, @samp{pentium-mmx}, @samp{pentiumpro}, @samp{pentium2},
+@samp{pentium3}, @samp{pentium4}, @samp{k6}, @samp{k6-2}, @samp{k6-3},
+@samp{athlon}, @samp{athlon-tbird}, @samp{athlon-4}, @samp{athlon-xp}
+and @samp{athlon-mp}.
+
+While picking a specific @var{cpu-type} will schedule things appropriately
+for that particular chip, the compiler will not generate any code that
+does not run on the i386 without the @option{-march=@var{cpu-type}} option
+being used.  @samp{i586} is equivalent to @samp{pentium} and @samp{i686}
+is equivalent to @samp{pentiumpro}.  @samp{k6} and @samp{athlon} are the
+AMD chips as opposed to the Intel ones.
+
+@item -march=@var{cpu-type}
+@opindex march
+Generate instructions for the machine type @var{cpu-type}.  The choices
+for @var{cpu-type} are the same as for @option{-mcpu}.  Moreover,
+specifying @option{-march=@var{cpu-type}} implies @option{-mcpu=@var{cpu-type}}.
+
+@item -m386
+@itemx -m486
+@itemx -mpentium
+@itemx -mpentiumpro
+@opindex m386
+@opindex m486
+@opindex mpentium
+@opindex mpentiumpro
+These options are synonyms for @option{-mcpu=i386}, @option{-mcpu=i486},
+@option{-mcpu=pentium}, and @option{-mcpu=pentiumpro} respectively.
+These synonyms are deprecated.
+
+@item -mfpmath=@var{unit}
+@opindex march
+generate floating point arithmetics for selected unit @var{unit}.  the choices
+for @var{unit} are:
+
+@table @samp
+@item 387
+Use the standard 387 floating point coprocessor present majority of chips and
+emulated otherwise.  Code compiled with this option will run almost everywhere.
+The temporary results are computed in 80bit precesion instead of precision
+specified by the type resulting in slightly different results compared to most
+of other chips. See @option{-ffloat-store} for more detailed description.
+
+This is the default choice for i386 compiler.
+
+@item sse
+Use scalar floating point instructions present in the SSE instruction set.
+This instruction set is supported by Pentium3 and newer chips, in the AMD line
+by Athlon-4, Athlon-xp and Athlon-mp chips.  The earlier version of SSE
+instruction set supports only single precision arithmetics, thus the double and
+extended precision arithmetics is still done using 387.  Later version, present
+only in Pentium4 and the future AMD x86-64 chips supports double precision
+arithmetics too.
+
+For i387 you need to use @option{-march=@var{cpu-type}}, @option{-msse} or
+@option{-msse2} switches to enable SSE extensions and make this option
+effective.  For x86-64 compiler, these extensions are enabled by default.
+
+The resulting code should be considerably faster in majority of cases and avoid
+the numerical instability problems of 387 code, but may break some existing
+code that expects temporaries to be 80bit.
+
+This is the default choice for x86-64 compiler.
+
+@item sse,387
+Attempt to utilize both instruction sets at once.  This effectivly double the
+amount of available registers and on chips with separate execution units for
+387 and SSE the execution resources too.  Use this option with care, as it is
+still experimental, because gcc register allocator does not model separate
+functional units well resulting in instable performance.
+@end table
+
+@item -masm=@var{dialect}
+@opindex masm=@var{dialect}
+Output asm instructions using selected @var{dialect}. Supported choices are
+@samp{intel} or @samp{att} (the default one).
+
+@item -mieee-fp
+@itemx -mno-ieee-fp
+@opindex mieee-fp
+@opindex mno-ieee-fp
+Control whether or not the compiler uses IEEE floating point
+comparisons.  These handle correctly the case where the result of a
+comparison is unordered.
+
+@item -msoft-float
+@opindex msoft-float
+Generate output containing library calls for floating point.
+@strong{Warning:} the requisite libraries are not part of GCC@.
+Normally the facilities of the machine's usual C compiler are used, but
+this can't be done directly in cross-compilation.  You must make your
+own arrangements to provide suitable library functions for
+cross-compilation.
+
+On machines where a function returns floating point results in the 80387
+register stack, some floating point opcodes may be emitted even if
+@option{-msoft-float} is used.
+
+@item -mno-fp-ret-in-387
+@opindex mno-fp-ret-in-387
+Do not use the FPU registers for return values of functions.
+
+The usual calling convention has functions return values of types
+@code{float} and @code{double} in an FPU register, even if there
+is no FPU@.  The idea is that the operating system should emulate
+an FPU@.
+
+The option @option{-mno-fp-ret-in-387} causes such values to be returned
+in ordinary CPU registers instead.
+
+@item -mno-fancy-math-387
+@opindex mno-fancy-math-387
+Some 387 emulators do not support the @code{sin}, @code{cos} and
+@code{sqrt} instructions for the 387.  Specify this option to avoid
+generating those instructions.  This option is the default on FreeBSD@.
+As of revision 2.6.1, these instructions are not generated unless you
+also use the @option{-funsafe-math-optimizations} switch.
+
+@item -malign-double
+@itemx -mno-align-double
+@opindex malign-double
+@opindex mno-align-double
+Control whether GCC aligns @code{double}, @code{long double}, and
+@code{long long} variables on a two word boundary or a one word
+boundary.  Aligning @code{double} variables on a two word boundary will
+produce code that runs somewhat faster on a @samp{Pentium} at the
+expense of more memory.
+
+@item -m128bit-long-double
+@opindex m128bit-long-double
+Control the size of @code{long double} type. i386 application binary interface
+specify the size to be 12 bytes, while modern architectures (Pentium and newer)
+prefer @code{long double} aligned to 8 or 16 byte boundary.  This is
+impossible to reach with 12 byte long doubles in the array accesses.
+
+@strong{Warning:} if you use the @option{-m128bit-long-double} switch, the
+structures and arrays containing @code{long double} will change their size as
+well as function calling convention for function taking @code{long double}
+will be modified.
+
+@item -m96bit-long-double
+@opindex m96bit-long-double
+Set the size of @code{long double} to 96 bits as required by the i386
+application binary interface.  This is the default.
+
+@item -msvr3-shlib
+@itemx -mno-svr3-shlib
+@opindex msvr3-shlib
+@opindex mno-svr3-shlib
+Control whether GCC places uninitialized local variables into the
+@code{bss} or @code{data} segments.  @option{-msvr3-shlib} places them
+into @code{bss}.  These options are meaningful only on System V Release 3.
+
+@item -mrtd
+@opindex mrtd
+Use a different function-calling convention, in which functions that
+take a fixed number of arguments return with the @code{ret} @var{num}
+instruction, which pops their arguments while returning.  This saves one
+instruction in the caller since there is no need to pop the arguments
+there.
+
+You can specify that an individual function is called with this calling
+sequence with the function attribute @samp{stdcall}.  You can also
+override the @option{-mrtd} option by using the function attribute
+@samp{cdecl}.  @xref{Function Attributes}.
+
+@strong{Warning:} this calling convention is incompatible with the one
+normally used on Unix, so you cannot use it if you need to call
+libraries compiled with the Unix compiler.
+
+Also, you must provide function prototypes for all functions that
+take variable numbers of arguments (including @code{printf});
+otherwise incorrect code will be generated for calls to those
+functions.
+
+In addition, seriously incorrect code will result if you call a
+function with too many arguments.  (Normally, extra arguments are
+harmlessly ignored.)
+
+@item -mregparm=@var{num}
+@opindex mregparm
+Control how many registers are used to pass integer arguments.  By
+default, no registers are used to pass arguments, and at most 3
+registers can be used.  You can control this behavior for a specific
+function by using the function attribute @samp{regparm}.
+@xref{Function Attributes}.
+
+@strong{Warning:} if you use this switch, and
+@var{num} is nonzero, then you must build all modules with the same
+value, including any libraries.  This includes the system libraries and
+startup modules.
+
+@item -mpreferred-stack-boundary=@var{num}
+@opindex mpreferred-stack-boundary
+Attempt to keep the stack boundary aligned to a 2 raised to @var{num}
+byte boundary.  If @option{-mpreferred-stack-boundary} is not specified,
+the default is 4 (16 bytes or 128 bits), except when optimizing for code
+size (@option{-Os}), in which case the default is the minimum correct
+alignment (4 bytes for x86, and 8 bytes for x86-64).
+
+On Pentium and PentiumPro, @code{double} and @code{long double} values
+should be aligned to an 8 byte boundary (see @option{-malign-double}) or
+suffer significant run time performance penalties.  On Pentium III, the
+Streaming SIMD Extension (SSE) data type @code{__m128} suffers similar
+penalties if it is not 16 byte aligned.
+
+To ensure proper alignment of this values on the stack, the stack boundary
+must be as aligned as that required by any value stored on the stack.
+Further, every function must be generated such that it keeps the stack
+aligned.  Thus calling a function compiled with a higher preferred
+stack boundary from a function compiled with a lower preferred stack
+boundary will most likely misalign the stack.  It is recommended that
+libraries that use callbacks always use the default setting.
+
+This extra alignment does consume extra stack space, and generally
+increases code size.  Code that is sensitive to stack space usage, such
+as embedded systems and operating system kernels, may want to reduce the
+preferred alignment to @option{-mpreferred-stack-boundary=2}.
+
+@item -mmmx
+@itemx -mno-mmx
+@item -msse
+@itemx -mno-sse
+@item -msse2
+@itemx -mno-sse2
+@item -m3dnow
+@itemx -mno-3dnow
+@opindex mmmx
+@opindex mno-mmx
+@opindex msse
+@opindex mno-sse
+@opindex m3dnow
+@opindex mno-3dnow
+These switches enable or disable the use of built-in functions that allow
+direct access to the MMX, SSE and 3Dnow extensions of the instruction set.
+
+@xref{X86 Built-in Functions}, for details of the functions enabled
+and disabled by these switches.
+
+@item -mpush-args
+@itemx -mno-push-args
+@opindex mpush-args
+@opindex mno-push-args
+Use PUSH operations to store outgoing parameters.  This method is shorter
+and usually equally fast as method using SUB/MOV operations and is enabled
+by default.  In some cases disabling it may improve performance because of
+improved scheduling and reduced dependencies.
+
+@item -maccumulate-outgoing-args
+@opindex maccumulate-outgoing-args
+If enabled, the maximum amount of space required for outgoing arguments will be
+computed in the function prologue.  This is faster on most modern CPUs
+because of reduced dependencies, improved scheduling and reduced stack usage
+when preferred stack boundary is not equal to 2.  The drawback is a notable
+increase in code size.  This switch implies @option{-mno-push-args}.
+
+@item -mthreads
+@opindex mthreads
+Support thread-safe exception handling on @samp{Mingw32}.  Code that relies
+on thread-safe exception handling must compile and link all code with the
+@option{-mthreads} option.  When compiling, @option{-mthreads} defines
+@option{-D_MT}; when linking, it links in a special thread helper library
+@option{-lmingwthrd} which cleans up per thread exception handling data.
+
+@item -mno-align-stringops
+@opindex mno-align-stringops
+Do not align destination of inlined string operations.  This switch reduces
+code size and improves performance in case the destination is already aligned,
+but gcc don't know about it.
+
+@item -minline-all-stringops
+@opindex minline-all-stringops
+By default GCC inlines string operations only when destination is known to be
+aligned at least to 4 byte boundary.  This enables more inlining, increase code
+size, but may improve performance of code that depends on fast memcpy, strlen
+and memset for short lengths.
+
+@item -momit-leaf-frame-pointer
+@opindex momit-leaf-frame-pointer
+Don't keep the frame pointer in a register for leaf functions.  This
+avoids the instructions to save, set up and restore frame pointers and
+makes an extra register available in leaf functions.  The option
+@option{-fomit-frame-pointer} removes the frame pointer for all functions
+which might make debugging harder.
+@end table
+
+These @samp{-m} switches are supported in addition to the above
+on AMD x86-64 processors in 64-bit environments.
+
+@table @gcctabopt
+@item -m32
+@itemx -m64
+@opindex m32
+@opindex m64
+Generate code for a 32-bit or 64-bit environment.
+The 32-bit environment sets int, long and pointer to 32 bits and
+generates code that runs on any i386 system.
+The 64-bit environment sets int to 32 bits and long and pointer
+to 64 bits and generates code for AMD's x86-64 architecture.
+
+@item -mno-red-zone
+@opindex no-red-zone
+Do not use a so called red zone for x86-64 code.  The red zone is mandated
+by the x86-64 ABI, it is a 128-byte area beyond the location of the
+stack pointer that will not be modified by signal or interrupt handlers
+and therefore can be used for temporary data without adjusting the stack
+pointer.  The flag @option{-mno-red-zone} disables this red zone.
+@end table
+
+@node HPPA Options
+@subsection HPPA Options
+@cindex HPPA Options
+
+These @samp{-m} options are defined for the HPPA family of computers:
+
+@table @gcctabopt
+@item -march=@var{architecture-type}
+@opindex march
+Generate code for the specified architecture.  The choices for
+@var{architecture-type} are @samp{1.0} for PA 1.0, @samp{1.1} for PA
+1.1, and @samp{2.0} for PA 2.0 processors.  Refer to
+@file{/usr/lib/sched.models} on an HP-UX system to determine the proper
+architecture option for your machine.  Code compiled for lower numbered
+architectures will run on higher numbered architectures, but not the
+other way around.
+
+PA 2.0 support currently requires gas snapshot 19990413 or later.  The
+next release of binutils (current is 2.9.1) will probably contain PA 2.0
+support.
+
+@item -mpa-risc-1-0
+@itemx -mpa-risc-1-1
+@itemx -mpa-risc-2-0
+@opindex mpa-risc-1-0
+@opindex mpa-risc-1-1
+@opindex mpa-risc-2-0
+Synonyms for @option{-march=1.0}, @option{-march=1.1}, and @option{-march=2.0} respectively.
+
+@item -mbig-switch
+@opindex mbig-switch
+Generate code suitable for big switch tables.  Use this option only if
+the assembler/linker complain about out of range branches within a switch
+table.
+
+@item -mjump-in-delay
+@opindex mjump-in-delay
+Fill delay slots of function calls with unconditional jump instructions
+by modifying the return pointer for the function call to be the target
+of the conditional jump.
+
+@item -mdisable-fpregs
+@opindex mdisable-fpregs
+Prevent floating point registers from being used in any manner.  This is
+necessary for compiling kernels which perform lazy context switching of
+floating point registers.  If you use this option and attempt to perform
+floating point operations, the compiler will abort.
+
+@item -mdisable-indexing
+@opindex mdisable-indexing
+Prevent the compiler from using indexing address modes.  This avoids some
+rather obscure problems when compiling MIG generated code under MACH@.
+
+@item -mno-space-regs
+@opindex mno-space-regs
+Generate code that assumes the target has no space registers.  This allows
+GCC to generate faster indirect calls and use unscaled index address modes.
+
+Such code is suitable for level 0 PA systems and kernels.
+
+@item -mfast-indirect-calls
+@opindex mfast-indirect-calls
+Generate code that assumes calls never cross space boundaries.  This
+allows GCC to emit code which performs faster indirect calls.
+
+This option will not work in the presence of shared libraries or nested
+functions.
+
+@item -mlong-load-store
+@opindex mlong-load-store
+Generate 3-instruction load and store sequences as sometimes required by
+the HP-UX 10 linker.  This is equivalent to the @samp{+k} option to
+the HP compilers.
+
+@item -mportable-runtime
+@opindex mportable-runtime
+Use the portable calling conventions proposed by HP for ELF systems.
+
+@item -mgas
+@opindex mgas
+Enable the use of assembler directives only GAS understands.
+
+@item -mschedule=@var{cpu-type}
+@opindex mschedule
+Schedule code according to the constraints for the machine type
+@var{cpu-type}.  The choices for @var{cpu-type} are @samp{700}
+@samp{7100}, @samp{7100LC}, @samp{7200}, and @samp{8000}.  Refer to
+@file{/usr/lib/sched.models} on an HP-UX system to determine the
+proper scheduling option for your machine.
+
+@item -mlinker-opt
+@opindex mlinker-opt
+Enable the optimization pass in the HPUX linker.  Note this makes symbolic
+debugging impossible.  It also triggers a bug in the HPUX 8 and HPUX 9 linkers
+in which they give bogus error messages when linking some programs.
+
+@item -msoft-float
+@opindex msoft-float
+Generate output containing library calls for floating point.
+@strong{Warning:} the requisite libraries are not available for all HPPA
+targets.  Normally the facilities of the machine's usual C compiler are
+used, but this cannot be done directly in cross-compilation.  You must make
+your own arrangements to provide suitable library functions for
+cross-compilation.  The embedded target @samp{hppa1.1-*-pro}
+does provide software floating point support.
+
+@option{-msoft-float} changes the calling convention in the output file;
+therefore, it is only useful if you compile @emph{all} of a program with
+this option.  In particular, you need to compile @file{libgcc.a}, the
+library that comes with GCC, with @option{-msoft-float} in order for
+this to work.
+@end table
+
+@node Intel 960 Options
+@subsection Intel 960 Options
+
+These @samp{-m} options are defined for the Intel 960 implementations:
+
+@table @gcctabopt
+@item -m@var{cpu-type}
+@opindex mka
+@opindex mkb
+@opindex mmc
+@opindex mca
+@opindex mcf
+@opindex msa
+@opindex msb
+Assume the defaults for the machine type @var{cpu-type} for some of
+the other options, including instruction scheduling, floating point
+support, and addressing modes.  The choices for @var{cpu-type} are
+@samp{ka}, @samp{kb}, @samp{mc}, @samp{ca}, @samp{cf},
+@samp{sa}, and @samp{sb}.
+The default is
+@samp{kb}.
+
+@item -mnumerics
+@itemx -msoft-float
+@opindex mnumerics
+@opindex msoft-float
+The @option{-mnumerics} option indicates that the processor does support
+floating-point instructions.  The @option{-msoft-float} option indicates
+that floating-point support should not be assumed.
+
+@item -mleaf-procedures
+@itemx -mno-leaf-procedures
+@opindex mleaf-procedures
+@opindex mno-leaf-procedures
+Do (or do not) attempt to alter leaf procedures to be callable with the
+@code{bal} instruction as well as @code{call}.  This will result in more
+efficient code for explicit calls when the @code{bal} instruction can be
+substituted by the assembler or linker, but less efficient code in other
+cases, such as calls via function pointers, or using a linker that doesn't
+support this optimization.
+
+@item -mtail-call
+@itemx -mno-tail-call
+@opindex mtail-call
+@opindex mno-tail-call
+Do (or do not) make additional attempts (beyond those of the
+machine-independent portions of the compiler) to optimize tail-recursive
+calls into branches.  You may not want to do this because the detection of
+cases where this is not valid is not totally complete.  The default is
+@option{-mno-tail-call}.
+
+@item -mcomplex-addr
+@itemx -mno-complex-addr
+@opindex mcomplex-addr
+@opindex mno-complex-addr
+Assume (or do not assume) that the use of a complex addressing mode is a
+win on this implementation of the i960.  Complex addressing modes may not
+be worthwhile on the K-series, but they definitely are on the C-series.
+The default is currently @option{-mcomplex-addr} for all processors except
+the CB and CC@.
+
+@item -mcode-align
+@itemx -mno-code-align
+@opindex mcode-align
+@opindex mno-code-align
+Align code to 8-byte boundaries for faster fetching (or don't bother).
+Currently turned on by default for C-series implementations only.
+
+@ignore
+@item -mclean-linkage
+@itemx -mno-clean-linkage
+@opindex mclean-linkage
+@opindex mno-clean-linkage
+These options are not fully implemented.
+@end ignore
+
+@item -mic-compat
+@itemx -mic2.0-compat
+@itemx -mic3.0-compat
+@opindex mic-compat
+@opindex mic2.0-compat
+@opindex mic3.0-compat
+Enable compatibility with iC960 v2.0 or v3.0.
+
+@item -masm-compat
+@itemx -mintel-asm
+@opindex masm-compat
+@opindex mintel-asm
+Enable compatibility with the iC960 assembler.
+
+@item -mstrict-align
+@itemx -mno-strict-align
+@opindex mstrict-align
+@opindex mno-strict-align
+Do not permit (do permit) unaligned accesses.
+
+@item -mold-align
+@opindex mold-align
+Enable structure-alignment compatibility with Intel's gcc release version
+1.3 (based on gcc 1.37).  This option implies @option{-mstrict-align}.
+
+@item -mlong-double-64
+@opindex mlong-double-64
+Implement type @samp{long double} as 64-bit floating point numbers.
+Without the option @samp{long double} is implemented by 80-bit
+floating point numbers.  The only reason we have it because there is
+no 128-bit @samp{long double} support in @samp{fp-bit.c} yet.  So it
+is only useful for people using soft-float targets.  Otherwise, we
+should recommend against use of it.
+
+@end table
+
+@node DEC Alpha Options
+@subsection DEC Alpha Options
+
+These @samp{-m} options are defined for the DEC Alpha implementations:
+
+@table @gcctabopt
+@item -mno-soft-float
+@itemx -msoft-float
+@opindex mno-soft-float
+@opindex msoft-float
+Use (do not use) the hardware floating-point instructions for
+floating-point operations.  When @option{-msoft-float} is specified,
+functions in @file{libgcc.a} will be used to perform floating-point
+operations.  Unless they are replaced by routines that emulate the
+floating-point operations, or compiled in such a way as to call such
+emulations routines, these routines will issue floating-point
+operations.   If you are compiling for an Alpha without floating-point
+operations, you must ensure that the library is built so as not to call
+them.
+
+Note that Alpha implementations without floating-point operations are
+required to have floating-point registers.
+
+@item -mfp-reg
+@itemx -mno-fp-regs
+@opindex mfp-reg
+@opindex mno-fp-regs
+Generate code that uses (does not use) the floating-point register set.
+@option{-mno-fp-regs} implies @option{-msoft-float}.  If the floating-point
+register set is not used, floating point operands are passed in integer
+registers as if they were integers and floating-point results are passed
+in @code{$0} instead of @code{$f0}.  This is a non-standard calling sequence,
+so any function with a floating-point argument or return value called by code
+compiled with @option{-mno-fp-regs} must also be compiled with that
+option.
+
+A typical use of this option is building a kernel that does not use,
+and hence need not save and restore, any floating-point registers.
+
+@item -mieee
+@opindex mieee
+The Alpha architecture implements floating-point hardware optimized for
+maximum performance.  It is mostly compliant with the IEEE floating
+point standard.  However, for full compliance, software assistance is
+required.  This option generates code fully IEEE compliant code
+@emph{except} that the @var{inexact-flag} is not maintained (see below).
+If this option is turned on, the preprocessor macro @code{_IEEE_FP} is
+defined during compilation.  The resulting code is less efficient but is
+able to correctly support denormalized numbers and exceptional IEEE
+values such as not-a-number and plus/minus infinity.  Other Alpha
+compilers call this option @option{-ieee_with_no_inexact}.
+
+@item -mieee-with-inexact
+@opindex mieee-with-inexact
+This is like @option{-mieee} except the generated code also maintains
+the IEEE @var{inexact-flag}.  Turning on this option causes the
+generated code to implement fully-compliant IEEE math.  In addition to
+@code{_IEEE_FP}, @code{_IEEE_FP_EXACT} is defined as a preprocessor
+macro.  On some Alpha implementations the resulting code may execute
+significantly slower than the code generated by default.  Since there is
+very little code that depends on the @var{inexact-flag}, you should
+normally not specify this option.  Other Alpha compilers call this
+option @option{-ieee_with_inexact}.
+
+@item -mfp-trap-mode=@var{trap-mode}
+@opindex mfp-trap-mode
+This option controls what floating-point related traps are enabled.
+Other Alpha compilers call this option @option{-fptm @var{trap-mode}}.
+The trap mode can be set to one of four values:
+
+@table @samp
+@item n
+This is the default (normal) setting.  The only traps that are enabled
+are the ones that cannot be disabled in software (e.g., division by zero
+trap).
+
+@item u
+In addition to the traps enabled by @samp{n}, underflow traps are enabled
+as well.
+
+@item su
+Like @samp{su}, but the instructions are marked to be safe for software
+completion (see Alpha architecture manual for details).
+
+@item sui
+Like @samp{su}, but inexact traps are enabled as well.
+@end table
+
+@item -mfp-rounding-mode=@var{rounding-mode}
+@opindex mfp-rounding-mode
+Selects the IEEE rounding mode.  Other Alpha compilers call this option
+@option{-fprm @var{rounding-mode}}.  The @var{rounding-mode} can be one
+of:
+
+@table @samp
+@item n
+Normal IEEE rounding mode.  Floating point numbers are rounded towards
+the nearest machine number or towards the even machine number in case
+of a tie.
+
+@item m
+Round towards minus infinity.
+
+@item c
+Chopped rounding mode.  Floating point numbers are rounded towards zero.
+
+@item d
+Dynamic rounding mode.  A field in the floating point control register
+(@var{fpcr}, see Alpha architecture reference manual) controls the
+rounding mode in effect.  The C library initializes this register for
+rounding towards plus infinity.  Thus, unless your program modifies the
+@var{fpcr}, @samp{d} corresponds to round towards plus infinity.
+@end table
+
+@item -mtrap-precision=@var{trap-precision}
+@opindex mtrap-precision
+In the Alpha architecture, floating point traps are imprecise.  This
+means without software assistance it is impossible to recover from a
+floating trap and program execution normally needs to be terminated.
+GCC can generate code that can assist operating system trap handlers
+in determining the exact location that caused a floating point trap.
+Depending on the requirements of an application, different levels of
+precisions can be selected:
+
+@table @samp
+@item p
+Program precision.  This option is the default and means a trap handler
+can only identify which program caused a floating point exception.
+
+@item f
+Function precision.  The trap handler can determine the function that
+caused a floating point exception.
+
+@item i
+Instruction precision.  The trap handler can determine the exact
+instruction that caused a floating point exception.
+@end table
+
+Other Alpha compilers provide the equivalent options called
+@option{-scope_safe} and @option{-resumption_safe}.
+
+@item -mieee-conformant
+@opindex mieee-conformant
+This option marks the generated code as IEEE conformant.  You must not
+use this option unless you also specify @option{-mtrap-precision=i} and either
+@option{-mfp-trap-mode=su} or @option{-mfp-trap-mode=sui}.  Its only effect
+is to emit the line @samp{.eflag 48} in the function prologue of the
+generated assembly file.  Under DEC Unix, this has the effect that
+IEEE-conformant math library routines will be linked in.
+
+@item -mbuild-constants
+@opindex mbuild-constants
+Normally GCC examines a 32- or 64-bit integer constant to
+see if it can construct it from smaller constants in two or three
+instructions.  If it cannot, it will output the constant as a literal and
+generate code to load it from the data segment at runtime.
+
+Use this option to require GCC to construct @emph{all} integer constants
+using code, even if it takes more instructions (the maximum is six).
+
+You would typically use this option to build a shared library dynamic
+loader.  Itself a shared library, it must relocate itself in memory
+before it can find the variables and constants in its own data segment.
+
+@item -malpha-as
+@itemx -mgas
+@opindex malpha-as
+@opindex mgas
+Select whether to generate code to be assembled by the vendor-supplied
+assembler (@option{-malpha-as}) or by the GNU assembler @option{-mgas}.
+
+@item -mbwx
+@itemx -mno-bwx
+@itemx -mcix
+@itemx -mno-cix
+@itemx -mfix
+@itemx -mno-fix
+@itemx -mmax
+@itemx -mno-max
+@opindex mbwx
+@opindex mno-bwx
+@opindex mcix
+@opindex mno-cix
+@opindex mfix
+@opindex mno-fix
+@opindex mmax
+@opindex mno-max
+Indicate whether GCC should generate code to use the optional BWX,
+CIX, FIX and MAX instruction sets.  The default is to use the instruction
+sets supported by the CPU type specified via @option{-mcpu=} option or that
+of the CPU on which GCC was built if none was specified.
+
+@item -mfloat-vax
+@itemx -mfloat-ieee
+@opindex mfloat-vax
+@opindex mfloat-ieee
+Generate code that uses (does not use) VAX F and G floating point
+arithmetic instead of IEEE single and double precision.
+
+@item -mexplicit-relocs
+@itemx -mno-explicit-relocs
+@opindex mexplicit-relocs
+@opindex mno-explicit-relocs
+Older Alpha assemblers provided no way to generate symbol relocations
+except via assembler macros.  Use of these macros does not allow 
+optimial instruction scheduling.  GNU binutils as of version 2.12
+supports a new syntax that allows the compiler to explicitly mark
+which relocations should apply to which instructions.  This option
+is mostly useful for debugging, as GCC detects the capabilities of
+the assembler when it is built and sets the default accordingly.
+
+@item -msmall-data
+@itemx -mlarge-data
+@opindex msmall-data
+@opindex mlarge-data
+When @option{-mexplicit-relocs} is in effect, static data is 
+accessed via @dfn{gp-relative} relocations.  When @option{-msmall-data}
+is used, objects 8 bytes long or smaller are placed in a @dfn{small data area}
+(the @code{.sdata} and @code{.sbss} sections) and are accessed via
+16-bit relocations off of the @code{$gp} register.  This limits the
+size of the small data area to 64KB, but allows the variables to be
+directly accessed via a single instruction.
+
+The default is @option{-mlarge-data}.  With this option the data area
+is limited to just below 2GB.  Programs that require more than 2GB of
+data must use @code{malloc} or @code{mmap} to allocate the data in the
+heap instead of in the program's data segment.
+
+When generating code for shared libraries, @option{-fpic} implies
+@option{-msmall-data} and @option{-fPIC} implies @option{-mlarge-data}.
+
+@item -mcpu=@var{cpu_type}
+@opindex mcpu
+Set the instruction set and instruction scheduling parameters for
+machine type @var{cpu_type}.  You can specify either the @samp{EV}
+style name or the corresponding chip number.  GCC supports scheduling
+parameters for the EV4, EV5 and EV6 family of processors and will
+choose the default values for the instruction set from the processor
+you specify.  If you do not specify a processor type, GCC will default
+to the processor on which the compiler was built.
+
+Supported values for @var{cpu_type} are
+
+@table @samp
+@item ev4
+@item ev45
+@itemx 21064
+Schedules as an EV4 and has no instruction set extensions.
+
+@item ev5
+@itemx 21164
+Schedules as an EV5 and has no instruction set extensions.
+
+@item ev56
+@itemx 21164a
+Schedules as an EV5 and supports the BWX extension.
+
+@item pca56
+@itemx 21164pc
+@itemx 21164PC
+Schedules as an EV5 and supports the BWX and MAX extensions.
+
+@item ev6
+@itemx 21264
+Schedules as an EV6 and supports the BWX, FIX, and MAX extensions.
+
+@item ev67
+@item 21264a
+Schedules as an EV6 and supports the BWX, CIX, FIX, and MAX extensions.
+@end table
+
+@item -mtune=@var{cpu_type}
+@opindex mtune
+Set only the instruction scheduling parameters for machine type
+@var{cpu_type}.  The instruction set is not changed.
+
+@item -mmemory-latency=@var{time}
+@opindex mmemory-latency
+Sets the latency the scheduler should assume for typical memory
+references as seen by the application.  This number is highly
+dependent on the memory access patterns used by the application
+and the size of the external cache on the machine.
+
+Valid options for @var{time} are
+
+@table @samp
+@item @var{number}
+A decimal number representing clock cycles.
+
+@item L1
+@itemx L2
+@itemx L3
+@itemx main
+The compiler contains estimates of the number of clock cycles for
+``typical'' EV4 & EV5 hardware for the Level 1, 2 & 3 caches
+(also called Dcache, Scache, and Bcache), as well as to main memory.
+Note that L3 is only valid for EV5.
+
+@end table
+@end table
+
+@node DEC Alpha/VMS Options
+@subsection DEC Alpha/VMS Options
+
+These @samp{-m} options are defined for the DEC Alpha/VMS implementations:
+
+@table @gcctabopt
+@item -mvms-return-codes
+@opindex mvms-return-codes
+Return VMS condition codes from main.  The default is to return POSIX
+style condition (e.g.@ error) codes.
+@end table
+
+@node Clipper Options
+@subsection Clipper Options
+
+These @samp{-m} options are defined for the Clipper implementations:
+
+@table @gcctabopt
+@item -mc300
+@opindex mc300
+Produce code for a C300 Clipper processor.  This is the default.
+
+@item -mc400
+@opindex mc400
+Produce code for a C400 Clipper processor, i.e.@: use floating point
+registers f8--f15.
+@end table
+
+@node H8/300 Options
+@subsection H8/300 Options
+
+These @samp{-m} options are defined for the H8/300 implementations:
+
+@table @gcctabopt
+@item -mrelax
+@opindex mrelax
+Shorten some address references at link time, when possible; uses the
+linker option @option{-relax}.  @xref{H8/300,, @code{ld} and the H8/300,
+ld.info, Using ld}, for a fuller description.
+
+@item -mh
+@opindex mh
+Generate code for the H8/300H@.
+
+@item -ms
+@opindex ms
+Generate code for the H8/S@.
+
+@item -ms2600
+@opindex ms2600
+Generate code for the H8/S2600.  This switch must be used with @option{-ms}.
+
+@item -mint32
+@opindex mint32
+Make @code{int} data 32 bits by default.
+
+@item -malign-300
+@opindex malign-300
+On the H8/300H and H8/S, use the same alignment rules as for the H8/300.
+The default for the H8/300H and H8/S is to align longs and floats on 4
+byte boundaries.
+@option{-malign-300} causes them to be aligned on 2 byte boundaries.
+This option has no effect on the H8/300.
+@end table
+
+@node SH Options
+@subsection SH Options
+
+These @samp{-m} options are defined for the SH implementations:
+
+@table @gcctabopt
+@item -m1
+@opindex m1
+Generate code for the SH1.
+
+@item -m2
+@opindex m2
+Generate code for the SH2.
+
+@item -m3
+@opindex m3
+Generate code for the SH3.
+
+@item -m3e
+@opindex m3e
+Generate code for the SH3e.
+
+@item -m4-nofpu
+@opindex m4-nofpu
+Generate code for the SH4 without a floating-point unit.
+
+@item -m4-single-only
+@opindex m4-single-only
+Generate code for the SH4 with a floating-point unit that only
+supports single-precision arithmetic.
+
+@item -m4-single
+@opindex m4-single
+Generate code for the SH4 assuming the floating-point unit is in
+single-precision mode by default.
+
+@item -m4
+@opindex m4
+Generate code for the SH4.
+
+@item -mb
+@opindex mb
+Compile code for the processor in big endian mode.
+
+@item -ml
+@opindex ml
+Compile code for the processor in little endian mode.
+
+@item -mdalign
+@opindex mdalign
+Align doubles at 64-bit boundaries.  Note that this changes the calling
+conventions, and thus some functions from the standard C library will
+not work unless you recompile it first with @option{-mdalign}.
+
+@item -mrelax
+@opindex mrelax
+Shorten some address references at link time, when possible; uses the
+linker option @option{-relax}.
+
+@item -mbigtable
+@opindex mbigtable
+Use 32-bit offsets in @code{switch} tables.  The default is to use
+16-bit offsets.
+
+@item -mfmovd
+@opindex mfmovd
+Enable the use of the instruction @code{fmovd}.
+
+@item -mhitachi
+@opindex mhitachi
+Comply with the calling conventions defined by Hitachi.
+
+@item -mnomacsave
+@opindex mnomacsave
+Mark the @code{MAC} register as call-clobbered, even if
+@option{-mhitachi} is given.
+
+@item -mieee
+@opindex mieee
+Increase IEEE-compliance of floating-point code.
+
+@item -misize
+@opindex misize
+Dump instruction size and location in the assembly code.
+
+@item -mpadstruct
+@opindex mpadstruct
+This option is deprecated.  It pads structures to multiple of 4 bytes,
+which is incompatible with the SH ABI@.
+
+@item -mspace
+@opindex mspace
+Optimize for space instead of speed.  Implied by @option{-Os}.
+
+@item -mprefergot
+@opindex mprefergot
+When generating position-independent code, emit function calls using
+the Global Offset Table instead of the Procedure Linkage Table.
+
+@item -musermode
+@opindex musermode
+Generate a library function call to invalidate instruction cache
+entries, after fixing up a trampoline.  This library function call
+doesn't assume it can write to the whole memory address space.  This
+is the default when the target is @code{sh-*-linux*}.
+@end table
+
+@node System V Options
+@subsection Options for System V
+
+These additional options are available on System V Release 4 for
+compatibility with other compilers on those systems:
+
+@table @gcctabopt
+@item -G
+@opindex G
+Create a shared object.
+It is recommended that @option{-symbolic} or @option{-shared} be used instead.
+
+@item -Qy
+@opindex Qy
+Identify the versions of each tool used by the compiler, in a
+@code{.ident} assembler directive in the output.
+
+@item -Qn
+@opindex Qn
+Refrain from adding @code{.ident} directives to the output file (this is
+the default).
+
+@item -YP,@var{dirs}
+@opindex YP
+Search the directories @var{dirs}, and no others, for libraries
+specified with @option{-l}.
+
+@item -Ym,@var{dir}
+@opindex Ym
+Look in the directory @var{dir} to find the M4 preprocessor.
+The assembler uses this option.
+@c This is supposed to go with a -Yd for predefined M4 macro files, but
+@c the generic assembler that comes with Solaris takes just -Ym.
+@end table
+
+@node TMS320C3x/C4x Options
+@subsection TMS320C3x/C4x Options
+@cindex TMS320C3x/C4x Options
+
+These @samp{-m} options are defined for TMS320C3x/C4x implementations:
+
+@table @gcctabopt
+
+@item -mcpu=@var{cpu_type}
+@opindex mcpu
+Set the instruction set, register set, and instruction scheduling
+parameters for machine type @var{cpu_type}.  Supported values for
+@var{cpu_type} are @samp{c30}, @samp{c31}, @samp{c32}, @samp{c40}, and
+@samp{c44}.  The default is @samp{c40} to generate code for the
+TMS320C40.
+
+@item -mbig-memory
+@item -mbig
+@itemx -msmall-memory
+@itemx -msmall
+@opindex mbig-memory
+@opindex mbig
+@opindex msmall-memory
+@opindex msmall
+Generates code for the big or small memory model.  The small memory
+model assumed that all data fits into one 64K word page.  At run-time
+the data page (DP) register must be set to point to the 64K page
+containing the .bss and .data program sections.  The big memory model is
+the default and requires reloading of the DP register for every direct
+memory access.
+
+@item -mbk
+@itemx -mno-bk
+@opindex mbk
+@opindex mno-bk
+Allow (disallow) allocation of general integer operands into the block
+count register BK@.
+
+@item -mdb
+@itemx -mno-db
+@opindex mdb
+@opindex mno-db
+Enable (disable) generation of code using decrement and branch,
+DBcond(D), instructions.  This is enabled by default for the C4x.  To be
+on the safe side, this is disabled for the C3x, since the maximum
+iteration count on the C3x is @math{2^23 + 1} (but who iterates loops more than
+@math{2^23} times on the C3x?).  Note that GCC will try to reverse a loop so
+that it can utilise the decrement and branch instruction, but will give
+up if there is more than one memory reference in the loop.  Thus a loop
+where the loop counter is decremented can generate slightly more
+efficient code, in cases where the RPTB instruction cannot be utilised.
+
+@item -mdp-isr-reload
+@itemx -mparanoid
+@opindex mdp-isr-reload
+@opindex mparanoid
+Force the DP register to be saved on entry to an interrupt service
+routine (ISR), reloaded to point to the data section, and restored on
+exit from the ISR@.  This should not be required unless someone has
+violated the small memory model by modifying the DP register, say within
+an object library.
+
+@item -mmpyi
+@itemx -mno-mpyi
+@opindex mmpyi
+@opindex mno-mpyi
+For the C3x use the 24-bit MPYI instruction for integer multiplies
+instead of a library call to guarantee 32-bit results.  Note that if one
+of the operands is a constant, then the multiplication will be performed
+using shifts and adds.  If the @option{-mmpyi} option is not specified for the C3x,
+then squaring operations are performed inline instead of a library call.
+
+@item -mfast-fix
+@itemx -mno-fast-fix
+@opindex mfast-fix
+@opindex mno-fast-fix
+The C3x/C4x FIX instruction to convert a floating point value to an
+integer value chooses the nearest integer less than or equal to the
+floating point value rather than to the nearest integer.  Thus if the
+floating point number is negative, the result will be incorrectly
+truncated an additional code is necessary to detect and correct this
+case.  This option can be used to disable generation of the additional
+code required to correct the result.
+
+@item -mrptb
+@itemx -mno-rptb
+@opindex mrptb
+@opindex mno-rptb
+Enable (disable) generation of repeat block sequences using the RPTB
+instruction for zero overhead looping.  The RPTB construct is only used
+for innermost loops that do not call functions or jump across the loop
+boundaries.  There is no advantage having nested RPTB loops due to the
+overhead required to save and restore the RC, RS, and RE registers.
+This is enabled by default with @option{-O2}.
+
+@item -mrpts=@var{count}
+@itemx -mno-rpts
+@opindex mrpts
+@opindex mno-rpts
+Enable (disable) the use of the single instruction repeat instruction
+RPTS@.  If a repeat block contains a single instruction, and the loop
+count can be guaranteed to be less than the value @var{count}, GCC will
+emit a RPTS instruction instead of a RPTB@.  If no value is specified,
+then a RPTS will be emitted even if the loop count cannot be determined
+at compile time.  Note that the repeated instruction following RPTS does
+not have to be reloaded from memory each iteration, thus freeing up the
+CPU buses for operands.  However, since interrupts are blocked by this
+instruction, it is disabled by default.
+
+@item -mloop-unsigned
+@itemx -mno-loop-unsigned
+@opindex mloop-unsigned
+@opindex mno-loop-unsigned
+The maximum iteration count when using RPTS and RPTB (and DB on the C40)
+is @math{2^31 + 1} since these instructions test if the iteration count is
+negative to terminate the loop.  If the iteration count is unsigned
+there is a possibility than the @math{2^31 + 1} maximum iteration count may be
+exceeded.  This switch allows an unsigned iteration count.
+
+@item -mti
+@opindex mti
+Try to emit an assembler syntax that the TI assembler (asm30) is happy
+with.  This also enforces compatibility with the API employed by the TI
+C3x C compiler.  For example, long doubles are passed as structures
+rather than in floating point registers.
+
+@item -mregparm
+@itemx -mmemparm
+@opindex mregparm
+@opindex mmemparm
+Generate code that uses registers (stack) for passing arguments to functions.
+By default, arguments are passed in registers where possible rather
+than by pushing arguments on to the stack.
+
+@item -mparallel-insns
+@itemx -mno-parallel-insns
+@opindex mparallel-insns
+@opindex mno-parallel-insns
+Allow the generation of parallel instructions.  This is enabled by
+default with @option{-O2}.
+
+@item -mparallel-mpy
+@itemx -mno-parallel-mpy
+@opindex mparallel-mpy
+@opindex mno-parallel-mpy
+Allow the generation of MPY||ADD and MPY||SUB parallel instructions,
+provided @option{-mparallel-insns} is also specified.  These instructions have
+tight register constraints which can pessimize the code generation
+of large functions.
+
+@end table
+
+@node V850 Options
+@subsection V850 Options
+@cindex V850 Options
+
+These @samp{-m} options are defined for V850 implementations:
+
+@table @gcctabopt
+@item -mlong-calls
+@itemx -mno-long-calls
+@opindex mlong-calls
+@opindex mno-long-calls
+Treat all calls as being far away (near).  If calls are assumed to be
+far away, the compiler will always load the functions address up into a
+register, and call indirect through the pointer.
+
+@item -mno-ep
+@itemx -mep
+@opindex mno-ep
+@opindex mep
+Do not optimize (do optimize) basic blocks that use the same index
+pointer 4 or more times to copy pointer into the @code{ep} register, and
+use the shorter @code{sld} and @code{sst} instructions.  The @option{-mep}
+option is on by default if you optimize.
+
+@item -mno-prolog-function
+@itemx -mprolog-function
+@opindex mno-prolog-function
+@opindex mprolog-function
+Do not use (do use) external functions to save and restore registers at
+the prolog and epilog of a function.  The external functions are slower,
+but use less code space if more than one function saves the same number
+of registers.  The @option{-mprolog-function} option is on by default if
+you optimize.
+
+@item -mspace
+@opindex mspace
+Try to make the code as small as possible.  At present, this just turns
+on the @option{-mep} and @option{-mprolog-function} options.
+
+@item -mtda=@var{n}
+@opindex mtda
+Put static or global variables whose size is @var{n} bytes or less into
+the tiny data area that register @code{ep} points to.  The tiny data
+area can hold up to 256 bytes in total (128 bytes for byte references).
+
+@item -msda=@var{n}
+@opindex msda
+Put static or global variables whose size is @var{n} bytes or less into
+the small data area that register @code{gp} points to.  The small data
+area can hold up to 64 kilobytes.
+
+@item -mzda=@var{n}
+@opindex mzda
+Put static or global variables whose size is @var{n} bytes or less into
+the first 32 kilobytes of memory.
+
+@item -mv850
+@opindex mv850
+Specify that the target processor is the V850.
+
+@item -mbig-switch
+@opindex mbig-switch
+Generate code suitable for big switch tables.  Use this option only if
+the assembler/linker complain about out of range branches within a switch
+table.
+@end table
+
+@node ARC Options
+@subsection ARC Options
+@cindex ARC Options
+
+These options are defined for ARC implementations:
+
+@table @gcctabopt
+@item -EL
+@opindex EL
+Compile code for little endian mode.  This is the default.
+
+@item -EB
+@opindex EB
+Compile code for big endian mode.
+
+@item -mmangle-cpu
+@opindex mmangle-cpu
+Prepend the name of the cpu to all public symbol names.
+In multiple-processor systems, there are many ARC variants with different
+instruction and register set characteristics.  This flag prevents code
+compiled for one cpu to be linked with code compiled for another.
+No facility exists for handling variants that are ``almost identical''.
+This is an all or nothing option.
+
+@item -mcpu=@var{cpu}
+@opindex mcpu
+Compile code for ARC variant @var{cpu}.
+Which variants are supported depend on the configuration.
+All variants support @option{-mcpu=base}, this is the default.
+
+@item -mtext=@var{text-section}
+@itemx -mdata=@var{data-section}
+@itemx -mrodata=@var{readonly-data-section}
+@opindex mtext
+@opindex mdata
+@opindex mrodata
+Put functions, data, and readonly data in @var{text-section},
+@var{data-section}, and @var{readonly-data-section} respectively
+by default.  This can be overridden with the @code{section} attribute.
+@xref{Variable Attributes}.
+
+@end table
+
+@node NS32K Options
+@subsection NS32K Options
+@cindex NS32K options
+
+These are the @samp{-m} options defined for the 32000 series.  The default
+values for these options depends on which style of 32000 was selected when
+the compiler was configured; the defaults for the most common choices are
+given below.
+
+@table @gcctabopt
+@item -m32032
+@itemx -m32032
+@opindex m32032
+@opindex m32032
+Generate output for a 32032.  This is the default
+when the compiler is configured for 32032 and 32016 based systems.
+
+@item -m32332
+@itemx -m32332
+@opindex m32332
+@opindex m32332
+Generate output for a 32332.  This is the default
+when the compiler is configured for 32332-based systems.
+
+@item -m32532
+@itemx -m32532
+@opindex m32532
+@opindex m32532
+Generate output for a 32532.  This is the default
+when the compiler is configured for 32532-based systems.
+
+@item -m32081
+@opindex m32081
+Generate output containing 32081 instructions for floating point.
+This is the default for all systems.
+
+@item -m32381
+@opindex m32381
+Generate output containing 32381 instructions for floating point.  This
+also implies @option{-m32081}.  The 32381 is only compatible with the 32332
+and 32532 cpus.  This is the default for the pc532-netbsd configuration.
+
+@item -mmulti-add
+@opindex mmulti-add
+Try and generate multiply-add floating point instructions @code{polyF}
+and @code{dotF}.  This option is only available if the @option{-m32381}
+option is in effect.  Using these instructions requires changes to
+register allocation which generally has a negative impact on
+performance.  This option should only be enabled when compiling code
+particularly likely to make heavy use of multiply-add instructions.
+
+@item -mnomulti-add
+@opindex mnomulti-add
+Do not try and generate multiply-add floating point instructions
+@code{polyF} and @code{dotF}.  This is the default on all platforms.
+
+@item -msoft-float
+@opindex msoft-float
+Generate output containing library calls for floating point.
+@strong{Warning:} the requisite libraries may not be available.
+
+@item -mnobitfield
+@opindex mnobitfield
+Do not use the bit-field instructions.  On some machines it is faster to
+use shifting and masking operations.  This is the default for the pc532.
+
+@item -mbitfield
+@opindex mbitfield
+Do use the bit-field instructions.  This is the default for all platforms
+except the pc532.
+
+@item -mrtd
+@opindex mrtd
+Use a different function-calling convention, in which functions
+that take a fixed number of arguments return pop their
+arguments on return with the @code{ret} instruction.
+
+This calling convention is incompatible with the one normally
+used on Unix, so you cannot use it if you need to call libraries
+compiled with the Unix compiler.
+
+Also, you must provide function prototypes for all functions that
+take variable numbers of arguments (including @code{printf});
+otherwise incorrect code will be generated for calls to those
+functions.
+
+In addition, seriously incorrect code will result if you call a
+function with too many arguments.  (Normally, extra arguments are
+harmlessly ignored.)
+
+This option takes its name from the 680x0 @code{rtd} instruction.
+
+
+@item -mregparam
+@opindex mregparam
+Use a different function-calling convention where the first two arguments
+are passed in registers.
+
+This calling convention is incompatible with the one normally
+used on Unix, so you cannot use it if you need to call libraries
+compiled with the Unix compiler.
+
+@item -mnoregparam
+@opindex mnoregparam
+Do not pass any arguments in registers.  This is the default for all
+targets.
+
+@item -msb
+@opindex msb
+It is OK to use the sb as an index register which is always loaded with
+zero.  This is the default for the pc532-netbsd target.
+
+@item -mnosb
+@opindex mnosb
+The sb register is not available for use or has not been initialized to
+zero by the run time system.  This is the default for all targets except
+the pc532-netbsd.  It is also implied whenever @option{-mhimem} or
+@option{-fpic} is set.
+
+@item -mhimem
+@opindex mhimem
+Many ns32000 series addressing modes use displacements of up to 512MB@.
+If an address is above 512MB then displacements from zero can not be used.
+This option causes code to be generated which can be loaded above 512MB@.
+This may be useful for operating systems or ROM code.
+
+@item -mnohimem
+@opindex mnohimem
+Assume code will be loaded in the first 512MB of virtual address space.
+This is the default for all platforms.
+
+
+@end table
+
+@node AVR Options
+@subsection AVR Options
+@cindex AVR Options
+
+These options are defined for AVR implementations:
+
+@table @gcctabopt
+@item -mmcu=@var{mcu}
+@opindex mmcu
+Specify ATMEL AVR instruction set or MCU type.
+
+Instruction set avr1 is for the minimal AVR core, not supported by the C
+compiler, only for assembler programs (MCU types: at90s1200, attiny10,
+attiny11, attiny12, attiny15, attiny28).
+
+Instruction set avr2 (default) is for the classic AVR core with up to
+8K program memory space (MCU types: at90s2313, at90s2323, attiny22,
+at90s2333, at90s2343, at90s4414, at90s4433, at90s4434, at90s8515,
+at90c8534, at90s8535).
+
+Instruction set avr3 is for the classic AVR core with up to 128K program
+memory space (MCU types: atmega103, atmega603, at43usb320, at76c711).
+
+Instruction set avr4 is for the enhanced AVR core with up to 8K program
+memory space (MCU types: atmega8, atmega83, atmega85).
+
+Instruction set avr5 is for the enhanced AVR core with up to 128K program
+memory space (MCU types: atmega16, atmega161, atmega163, atmega32, atmega323,
+atmega64, atmega128, at43usb355, at94k).
+
+@item -msize
+@opindex msize
+Output instruction sizes to the asm file.
+
+@item -minit-stack=@var{N}
+@opindex minit-stack
+Specify the initial stack address, which may be a symbol or numeric value,
+@samp{__stack} is the default.
+
+@item -mno-interrupts
+@opindex mno-interrupts
+Generated code is not compatible with hardware interrupts.
+Code size will be smaller.
+
+@item -mcall-prologues
+@opindex mcall-prologues
+Functions prologues/epilogues expanded as call to appropriate
+subroutines.  Code size will be smaller.
+
+@item -mno-tablejump
+@opindex mno-tablejump
+Do not generate tablejump insns which sometimes increase code size.
+
+@item -mtiny-stack
+@opindex mtiny-stack
+Change only the low 8 bits of the stack pointer.
+@end table
+
+@node MCore Options
+@subsection MCore Options
+@cindex MCore options
+
+These are the @samp{-m} options defined for the Motorola M*Core
+processors.
+
+@table @gcctabopt
+
+@item -mhardlit
+@itemx -mhardlit
+@itemx -mno-hardlit
+@opindex mhardlit
+@opindex mhardlit
+@opindex mno-hardlit
+Inline constants into the code stream if it can be done in two
+instructions or less.
+
+@item -mdiv
+@itemx -mdiv
+@itemx -mno-div
+@opindex mdiv
+@opindex mdiv
+@opindex mno-div
+Use the divide instruction.  (Enabled by default).
+
+@item -mrelax-immediate
+@itemx -mrelax-immediate
+@itemx -mno-relax-immediate
+@opindex mrelax-immediate
+@opindex mrelax-immediate
+@opindex mno-relax-immediate
+Allow arbitrary sized immediates in bit operations.
+
+@item -mwide-bitfields
+@itemx -mwide-bitfields
+@itemx -mno-wide-bitfields
+@opindex mwide-bitfields
+@opindex mwide-bitfields
+@opindex mno-wide-bitfields
+Always treat bit-fields as int-sized.
+
+@item -m4byte-functions
+@itemx -m4byte-functions
+@itemx -mno-4byte-functions
+@opindex m4byte-functions
+@opindex m4byte-functions
+@opindex mno-4byte-functions
+Force all functions to be aligned to a four byte boundary.
+
+@item -mcallgraph-data
+@itemx -mcallgraph-data
+@itemx -mno-callgraph-data
+@opindex mcallgraph-data
+@opindex mcallgraph-data
+@opindex mno-callgraph-data
+Emit callgraph information.
+
+@item -mslow-bytes
+@itemx -mslow-bytes
+@itemx -mno-slow-bytes
+@opindex mslow-bytes
+@opindex mslow-bytes
+@opindex mno-slow-bytes
+Prefer word access when reading byte quantities.
+
+@item -mlittle-endian
+@itemx -mlittle-endian
+@itemx -mbig-endian
+@opindex mlittle-endian
+@opindex mlittle-endian
+@opindex mbig-endian
+Generate code for a little endian target.
+
+@item -m210
+@itemx -m210
+@itemx -m340
+@opindex m210
+@opindex m210
+@opindex m340
+Generate code for the 210 processor.
+@end table
+
+@node IA-64 Options
+@subsection IA-64 Options
+@cindex IA-64 Options
+
+These are the @samp{-m} options defined for the Intel IA-64 architecture.
+
+@table @gcctabopt
+@item -mbig-endian
+@opindex mbig-endian
+Generate code for a big endian target.  This is the default for HPUX@.
+
+@item -mlittle-endian
+@opindex mlittle-endian
+Generate code for a little endian target.  This is the default for AIX5
+and Linux.
+
+@item -mgnu-as
+@itemx -mno-gnu-as
+@opindex mgnu-as
+@opindex mno-gnu-as
+Generate (or don't) code for the GNU assembler.  This is the default.
+@c Also, this is the default if the configure option @option{--with-gnu-as}
+@c is used.
+
+@item -mgnu-ld
+@itemx -mno-gnu-ld
+@opindex mgnu-ld
+@opindex mno-gnu-ld
+Generate (or don't) code for the GNU linker.  This is the default.
+@c Also, this is the default if the configure option @option{--with-gnu-ld}
+@c is used.
+
+@item -mno-pic
+@opindex mno-pic
+Generate code that does not use a global pointer register.  The result
+is not position independent code, and violates the IA-64 ABI@.
+
+@item -mvolatile-asm-stop
+@itemx -mno-volatile-asm-stop
+@opindex mvolatile-asm-stop
+@opindex mno-volatile-asm-stop
+Generate (or don't) a stop bit immediately before and after volatile asm
+statements.
+
+@item -mb-step
+@opindex mb-step
+Generate code that works around Itanium B step errata.
+
+@item -mregister-names
+@itemx -mno-register-names
+@opindex mregister-names
+@opindex mno-register-names
+Generate (or don't) @samp{in}, @samp{loc}, and @samp{out} register names for
+the stacked registers.  This may make assembler output more readable.
+
+@item -mno-sdata
+@itemx -msdata
+@opindex mno-sdata
+@opindex msdata
+Disable (or enable) optimizations that use the small data section.  This may
+be useful for working around optimizer bugs.
+
+@item -mconstant-gp
+@opindex mconstant-gp
+Generate code that uses a single constant global pointer value.  This is
+useful when compiling kernel code.
+
+@item -mauto-pic
+@opindex mauto-pic
+Generate code that is self-relocatable.  This implies @option{-mconstant-gp}.
+This is useful when compiling firmware code.
+
+@item -minline-divide-min-latency
+@opindex minline-divide-min-latency
+Generate code for inline divides using the minimum latency algorithm.
+
+@item -minline-divide-max-throughput
+@opindex minline-divide-max-throughput
+Generate code for inline divides using the maximum throughput algorithm.
+
+@item -mno-dwarf2-asm
+@itemx -mdwarf2-asm
+@opindex mno-dwarf2-asm
+@opindex mdwarf2-asm
+Don't (or do) generate assembler code for the DWARF2 line number debugging
+info.  This may be useful when not using the GNU assembler.
+
+@item -mfixed-range=@var{register-range}
+@opindex mfixed-range
+Generate code treating the given register range as fixed registers.
+A fixed register is one that the register allocator can not use.  This is
+useful when compiling kernel code.  A register range is specified as
+two registers separated by a dash.  Multiple register ranges can be
+specified separated by a comma.
+@end table
+
+@node D30V Options
+@subsection D30V Options
+@cindex D30V Options
+
+These @samp{-m} options are defined for D30V implementations:
+
+@table @gcctabopt
+@item -mextmem
+@opindex mextmem
+Link the @samp{.text}, @samp{.data}, @samp{.bss}, @samp{.strings},
+@samp{.rodata}, @samp{.rodata1}, @samp{.data1} sections into external
+memory, which starts at location @code{0x80000000}.
+
+@item -mextmemory
+@opindex mextmemory
+Same as the @option{-mextmem} switch.
+
+@item -monchip
+@opindex monchip
+Link the @samp{.text} section into onchip text memory, which starts at
+location @code{0x0}.  Also link @samp{.data}, @samp{.bss},
+@samp{.strings}, @samp{.rodata}, @samp{.rodata1}, @samp{.data1} sections
+into onchip data memory, which starts at location @code{0x20000000}.
+
+@item -mno-asm-optimize
+@itemx -masm-optimize
+@opindex mno-asm-optimize
+@opindex masm-optimize
+Disable (enable) passing @option{-O} to the assembler when optimizing.
+The assembler uses the @option{-O} option to automatically parallelize
+adjacent short instructions where possible.
+
+@item -mbranch-cost=@var{n}
+@opindex mbranch-cost
+Increase the internal costs of branches to @var{n}.  Higher costs means
+that the compiler will issue more instructions to avoid doing a branch.
+The default is 2.
+
+@item -mcond-exec=@var{n}
+@opindex mcond-exec
+Specify the maximum number of conditionally executed instructions that
+replace a branch.  The default is 4.
+@end table
+
+@node S/390 and zSeries Options
+@subsection S/390 and zSeries Options
+@cindex S/390 and zSeries Options
+
+These are the @samp{-m} options defined for the S/390 and zSeries architecture.
+
+@table @gcctabopt
+@item -mhard-float
+@itemx -msoft-float
+@opindex mhard-float
+@opindex msoft-float
+Use (do not use) the hardware floating-point instructions and registers
+for floating-point operations.  When @option{-msoft-float} is specified,
+functions in @file{libgcc.a} will be used to perform floating-point
+operations.  When @option{-mhard-float} is specified, the compiler
+generates IEEE floating-point instructions.  This is the default.
+
+@item -mbackchain
+@itemx -mno-backchain
+@opindex mbackchain
+@opindex mno-backchain
+Generate (or do not generate) code which maintains an explicit 
+backchain within the stack frame that points to the caller's frame.
+This is currently needed to allow debugging.  The default is to
+generate the backchain.
+
+@item -msmall-exec
+@itemx -mno-small-exec
+@opindex msmall-exec
+@opindex mno-small-exec
+Generate (or do not generate) code using the @code{bras} instruction 
+to do subroutine calls. 
+This only works reliably if the total executable size does not
+exceed 64k.  The default is to use the @code{basr} instruction instead,
+which does not have this limitation.
+
+@item -m64
+@itemx -m31
+@opindex m64
+@opindex m31
+When @option{-m31} is specified, generate code compliant to the
+Linux for S/390 ABI@.  When @option{-m64} is specified, generate
+code compliant to the Linux for zSeries ABI@.  This allows GCC in
+particular to generate 64-bit instructions.  For the @samp{s390}
+targets, the default is @option{-m31}, while the @samp{s390x} 
+targets default to @option{-m64}.
+
+@item -mmvcle
+@itemx -mno-mvcle
+@opindex mmvcle
+@opindex mno-mvcle
+Generate (or do not generate) code using the @code{mvcle} instruction 
+to perform block moves.  When @option{-mno-mvcle} is specifed,
+use a @code{mvc} loop instead.  This is the default.
+
+@item -mdebug
+@itemx -mno-debug
+@opindex mdebug
+@opindex mno-debug
+Print (or do not print) additional debug information when compiling.
+The default is to not print debug information.
+
+@end table
+
+@node CRIS Options
+@subsection CRIS Options
+@cindex CRIS Options
+
+These options are defined specifically for the CRIS ports.
+
+@table @gcctabopt
+@item -march=@var{architecture-type}
+@itemx -mcpu=@var{architecture-type}
+@opindex march
+@opindex mcpu
+Generate code for the specified architecture.  The choices for
+@var{architecture-type} are @samp{v3}, @samp{v8} and @samp{v10} for
+respectively ETRAX@w{ }4, ETRAX@w{ }100, and ETRAX@w{ }100@w{ }LX.
+Default is @samp{v0} except for cris-axis-linux-gnu, where the default is
+@samp{v10}.
+
+@item -mtune=@var{architecture-type}
+@opindex mtune
+Tune to @var{architecture-type} everything applicable about the generated
+code, except for the ABI and the set of available instructions.  The
+choices for @var{architecture-type} are the same as for
+@option{-march=@var{architecture-type}}.
+
+@item -mmax-stack-frame=@var{n}
+@opindex mmax-stack-frame
+Warn when the stack frame of a function exceeds @var{n} bytes.
+
+@item -melinux-stacksize=@var{n}
+@opindex melinux-stacksize
+Only available with the @samp{cris-axis-aout} target.  Arranges for
+indications in the program to the kernel loader that the stack of the
+program should be set to @var{n} bytes.
+
+@item -metrax4
+@itemx -metrax100
+@opindex metrax4
+@opindex metrax100
+The options @option{-metrax4} and @option{-metrax100} are synonyms for
+@option{-march=v3} and @option{-march=v8} respectively.
+
+@item -mpdebug
+@opindex mpdebug
+Enable CRIS-specific verbose debug-related information in the assembly
+code.  This option also has the effect to turn off the @samp{#NO_APP}
+formatted-code indicator to the assembler at the beginning of the
+assembly file.
+
+@item -mcc-init
+@opindex mcc-init
+Do not use condition-code results from previous instruction; always emit
+compare and test instructions before use of condition codes.
+
+@item -mno-side-effects
+@opindex mno-side-effects
+Do not emit instructions with side-effects in addressing modes other than
+post-increment.
+
+@item -mstack-align
+@itemx -mno-stack-align
+@itemx -mdata-align
+@itemx -mno-data-align
+@itemx -mconst-align
+@itemx -mno-const-align
+@opindex mstack-align
+@opindex mno-stack-align
+@opindex mdata-align
+@opindex mno-data-align
+@opindex mconst-align
+@opindex mno-const-align
+These options (no-options) arranges (eliminate arrangements) for the
+stack-frame, individual data and constants to be aligned for the maximum
+single data access size for the chosen CPU model.  The default is to
+arrange for 32-bit alignment.  ABI details such as structure layout are
+not affected by these options.
+
+@item -m32-bit
+@itemx -m16-bit
+@itemx -m8-bit
+@opindex m32-bit
+@opindex m16-bit
+@opindex m8-bit
+Similar to the stack- data- and const-align options above, these options
+arrange for stack-frame, writable data and constants to all be 32-bit,
+16-bit or 8-bit aligned.  The default is 32-bit alignment.
+
+@item -mno-prologue-epilogue
+@itemx -mprologue-epilogue
+@opindex mno-prologue-epilogue
+@opindex mprologue-epilogue
+With @option{-mno-prologue-epilogue}, the normal function prologue and
+epilogue that sets up the stack-frame are omitted and no return
+instructions or return sequences are generated in the code.  Use this
+option only together with visual inspection of the compiled code: no
+warnings or errors are generated when call-saved registers must be saved,
+or storage for local variable needs to be allocated.
+
+@item -mno-gotplt
+@itemx -mgotplt
+@opindex mno-gotplt
+@opindex mgotplt
+With @option{-fpic} and @option{-fPIC}, don't generate (do generate)
+instruction sequences that load addresses for functions from the PLT part
+of the GOT rather than (traditional on other architectures) calls to the
+PLT.  The default is @option{-mgotplt}.
+
+@item -maout
+@opindex maout
+Legacy no-op option only recognized with the cris-axis-aout target.
+
+@item -melf
+@opindex melf
+Legacy no-op option only recognized with the cris-axis-elf and
+cris-axis-linux-gnu targets.
+
+@item -melinux
+@opindex melinux
+Only recognized with the cris-axis-aout target, where it selects a
+GNU/linux-like multilib, include files and instruction set for
+@option{-march=v8}.
+
+@item -mlinux
+@opindex mlinux
+Legacy no-op option only recognized with the cris-axis-linux-gnu target.
+
+@item -sim
+@opindex sim
+This option, recognized for the cris-axis-aout and cris-axis-elf arranges
+to link with input-output functions from a simulator library.  Code,
+initialized data and zero-initialized data are allocated consecutively.
+
+@item -sim2
+@opindex sim2
+Like @option{-sim}, but pass linker options to locate initialized data at
+0x40000000 and zero-initialized data at 0x80000000.
+@end table
+
+@node MMIX Options
+@subsection MMIX Options
+@cindex MMIX Options
+
+These options are defined for the MMIX:
+
+@table @gcctabopt
+@item -mlibfuncs
+@itemx -mno-libfuncs
+@opindex mlibfuncs
+@opindex mno-libfuncs
+Specify that intrinsic library functions are being compiled, passing all
+values in registers, no matter the size.
+
+@item -mepsilon
+@itemx -mno-epsilon
+@opindex mepsilon
+@opindex mno-epsilon
+Generate floating-point comparison instructions that compare with respect
+to the @code{rE} epsilon register.
+
+@item -mabi=mmixware
+@itemx -mabi=gnu
+@opindex mabi-mmixware
+@opindex mabi=gnu
+Generate code that passes function parameters and return values that (in
+the called function) are seen as registers @code{$0} and up, as opposed to
+the GNU ABI which uses global registers @code{$231} and up.
+
+@item -mzero-extend
+@itemx -mno-zero-extend
+@opindex mzero-extend
+@opindex mno-zero-extend
+When reading data from memory in sizes shorter than 64 bits, use (do not
+use) zero-extending load instructions by default, rather than
+sign-extending ones.
+
+@item -mknuthdiv
+@itemx -mno-knuthdiv
+@opindex mknuthdiv
+@opindex mno-knuthdiv
+Make the result of a division yielding a remainder have the same sign as
+the divisor.  With the default, @option{-mno-knuthdiv}, the sign of the
+remainder follows the sign of the dividend.  Both methods are
+arithmetically valid, the latter being almost exclusively used.
+
+@item -mtoplevel-symbols
+@itemx -mno-toplevel-symbols
+@opindex mtoplevel-symbols
+@opindex mno-toplevel-symbols
+Prepend (do not prepend) a @samp{:} to all global symbols, so the assembly
+code can be used with the @code{PREFIX} assembly directive.
+
+@item -melf
+@opindex melf
+Generate an executable in the ELF format, rather than the default
+@samp{mmo} format used by the @command{mmix} simulator.
+
+@item -mbranch-predict
+@itemx -mno-branch-predict
+@opindex mbranch-predict
+@opindex mno-branch-predict
+Use (do not use) the probable-branch instructions, when static branch
+prediction indicates a probable branch.
+@end table
+
+@node PDP-11 Options
+@subsection PDP-11 Options
+@cindex PDP-11 Options
+
+These options are defined for the PDP-11:
+
+@table @gcctabopt
+@item -mfpu
+@opindex mfpu
+Use hardware FPP floating point.  This is the default.  (FIS floating
+point on the PDP-11/40 is not supported.)
+
+@item -msoft-float
+@opindex msoft-float
+Do not use hardware floating point.
+
+@item -mac0
+@opindex mac0
+Return floating-point results in ac0 (fr0 in Unix assembler syntax).
+
+@item -mno-ac0
+@opindex mno-ac0
+Return floating-point results in memory.  This is the default.
+
+@item -m40
+@opindex m40
+Generate code for a PDP-11/40.
+
+@item -m45
+@opindex m45
+Generate code for a PDP-11/45.  This is the default.
+
+@item -m10
+@opindex m10
+Generate code for a PDP-11/10.
+
+@item -mbcopy-builtin
+@opindex bcopy-builtin
+Use inline @code{movstrhi} patterns for copying memory.  This is the
+default.
+
+@item -mbcopy
+@opindex mbcopy
+Do not use inline @code{movstrhi} patterns for copying memory.
+
+@item -mint16
+@itemx -mno-int32
+@opindex mint16
+@opindex mno-int32
+Use 16-bit @code{int}.  This is the default.
+
+@item -mint32
+@itemx -mno-int16
+@opindex mint32
+@opindex mno-int16
+Use 32-bit @code{int}.
+
+@item -mfloat64
+@itemx -mno-float32
+@opindex mfloat64
+@opindex mno-float32
+Use 64-bit @code{float}.  This is the default.
+
+@item -mfloat32
+@item -mno-float64
+@opindex mfloat32
+@opindex mno-float64
+Use 32-bit @code{float}.
+
+@item -mabshi
+@opindex mabshi
+Use @code{abshi2} pattern.  This is the default.
+
+@item -mno-abshi
+@opindex mno-abshi
+Do not use @code{abshi2} pattern.
+
+@item -mbranch-expensive
+@opindex mbranch-expensive
+Pretend that branches are expensive.  This is for experimenting with
+code generation only.
+
+@item -mbranch-cheap
+@opindex mbranch-cheap
+Do not pretend that branches are expensive.  This is the default.
+
+@item -msplit
+@opindex msplit
+Generate code for a system with split I&D.
+
+@item -mno-split
+@opindex mno-split
+Generate code for a system without split I&D.  This is the default.
+
+@item -munix-asm
+@opindex munix-asm
+Use Unix assembler syntax.  This is the default when configured for
+@samp{pdp11-*-bsd}.
+
+@item -mdec-asm
+@opindex mdec-asm
+Use DEC assembler syntax.  This is the default when configured for any
+PDP-11 target other than @samp{pdp11-*-bsd}.
+@end table
+
+@node Xstormy16 Options
+@subsection Xstormy16 Options
+@cindex Xstormy16 Options
+
+These options are defined for Xstormy16:
+
+@table @gcctabopt
+@item -msim
+@opindex msim
+Choose startup files and linker script suitable for the simulator.
+@end table
+
+@node Xtensa Options
+@subsection Xtensa Options
+@cindex Xtensa Options
+
+The Xtensa architecture is designed to support many different
+configurations.  The compiler's default options can be set to match a
+particular Xtensa configuration by copying a configuration file into the
+GCC sources when building GCC@.  The options below may be used to
+override the default options.
+
+@table @gcctabopt
+@item -mbig-endian
+@itemx -mlittle-endian
+@opindex mbig-endian
+@opindex mlittle-endian
+Specify big-endian or little-endian byte ordering for the target Xtensa
+processor.
+
+@item -mdensity
+@itemx -mno-density
+@opindex mdensity
+@opindex mno-density
+Enable or disable use of the optional Xtensa code density instructions.
+
+@item -mmac16
+@itemx -mno-mac16
+@opindex mmac16
+@opindex mno-mac16
+Enable or disable use of the Xtensa MAC16 option.  When enabled, GCC
+will generate MAC16 instructions from standard C code, with the
+limitation that it will use neither the MR register file nor any
+instruction that operates on the MR registers.  When this option is
+disabled, GCC will translate 16-bit multiply/accumulate operations to a
+combination of core instructions and library calls, depending on whether
+any other multiplier options are enabled.
+
+@item -mmul16
+@itemx -mno-mul16
+@opindex mmul16
+@opindex mno-mul16
+Enable or disable use of the 16-bit integer multiplier option.  When
+enabled, the compiler will generate 16-bit multiply instructions for
+multiplications of 16 bits or smaller in standard C code.  When this
+option is disabled, the compiler will either use 32-bit multiply or
+MAC16 instructions if they are available or generate library calls to
+perform the multiply operations using shifts and adds.
+
+@item -mmul32
+@itemx -mno-mul32
+@opindex mmul32
+@opindex mno-mul32
+Enable or disable use of the 32-bit integer multiplier option.  When
+enabled, the compiler will generate 32-bit multiply instructions for
+multiplications of 32 bits or smaller in standard C code.  When this
+option is disabled, the compiler will generate library calls to perform
+the multiply operations using either shifts and adds or 16-bit multiply
+instructions if they are available.
+
+@item -mnsa
+@itemx -mno-nsa
+@opindex mnsa
+@opindex mno-nsa
+Enable or disable use of the optional normalization shift amount
+(@code{NSA}) instructions to implement the built-in @code{ffs} function.
+
+@item -mminmax
+@itemx -mno-minmax
+@opindex mminmax
+@opindex mno-minmax
+Enable or disable use of the optional minimum and maximum value
+instructions.
+
+@item -msext
+@itemx -mno-sext
+@opindex msext
+@opindex mno-sext
+Enable or disable use of the optional sign extend (@code{SEXT})
+instruction.
+
+@item -mbooleans
+@itemx -mno-booleans
+@opindex mbooleans
+@opindex mno-booleans
+Enable or disable support for the boolean register file used by Xtensa
+coprocessors.  This is not typically useful by itself but may be
+required for other options that make use of the boolean registers (e.g.,
+the floating-point option).
+
+@item -mhard-float
+@itemx -msoft-float
+@opindex mhard-float
+@opindex msoft-float
+Enable or disable use of the floating-point option.  When enabled, GCC
+generates floating-point instructions for 32-bit @code{float}
+operations.  When this option is disabled, GCC generates library calls
+to emulate 32-bit floating-point operations using integer instructions.
+Regardless of this option, 64-bit @code{double} operations are always
+emulated with calls to library functions.
+
+@item -mfused-madd
+@itemx -mno-fused-madd
+@opindex mfused-madd
+@opindex mno-fused-madd
+Enable or disable use of fused multiply/add and multiply/subtract
+instructions in the floating-point option.  This has no effect if the
+floating-point option is not also enabled.  Disabling fused multiply/add
+and multiply/subtract instructions forces the compiler to use separate
+instructions for the multiply and add/subtract operations.  This may be
+desirable in some cases where strict IEEE 754-compliant results are
+required: the fused multiply add/subtract instructions do not round the
+intermediate result, thereby producing results with @emph{more} bits of
+precision than specified by the IEEE standard.  Disabling fused multiply
+add/subtract instructions also ensures that the program output is not
+sensitive to the compiler's ability to combine multiply and add/subtract
+operations.
+
+@item -mserialize-volatile
+@itemx -mno-serialize-volatile
+@opindex mserialize-volatile
+@opindex mno-serialize-volatile
+When this option is enabled, GCC inserts @code{MEMW} instructions before
+@code{volatile} memory references to guarantee sequential consistency.
+The default is @option{-mserialize-volatile}.  Use
+@option{-mno-serialize-volatile} to omit the @code{MEMW} instructions.
+
+@item -mtext-section-literals
+@itemx -mno-text-section-literals
+@opindex mtext-section-literals
+@opindex mno-text-section-literals
+Control the treatment of literal pools.  The default is
+@option{-mno-text-section-literals}, which places literals in a separate
+section in the output file.  This allows the literal pool to be placed
+in a data RAM/ROM, and it also allows the linker to combine literal
+pools from separate object files to remove redundant literals and
+improve code size.  With @option{-mtext-section-literals}, the literals
+are interspersed in the text section in order to keep them as close as
+possible to their references.  This may be necessary for large assembly
+files.
+
+@item -mtarget-align
+@itemx -mno-target-align
+@opindex mtarget-align
+@opindex mno-target-align
+When this option is enabled, GCC instructs the assembler to
+automatically align instructions to reduce branch penalties at the
+expense of some code density.  The assembler attempts to widen density
+instructions to align branch targets and the instructions following call
+instructions.  If there are not enough preceding safe density
+instructions to align a target, no widening will be performed.  The
+default is @option{-mtarget-align}.  These options do not affect the
+treatment of auto-aligned instructions like @code{LOOP}, which the
+assembler will always align, either by widening density instructions or
+by inserting no-op instructions.
+
+@item -mlongcalls
+@itemx -mno-longcalls
+@opindex mlongcalls
+@opindex mno-longcalls
+When this option is enabled, GCC instructs the assembler to translate
+direct calls to indirect calls unless it can determine that the target
+of a direct call is in the range allowed by the call instruction.  This
+translation typically occurs for calls to functions in other source
+files.  Specifically, the assembler translates a direct @code{CALL}
+instruction into an @code{L32R} followed by a @code{CALLX} instruction.
+The default is @option{-mno-longcalls}.  This option should be used in
+programs where the call target can potentially be out of range.  This
+option is implemented in the assembler, not the compiler, so the
+assembly code generated by GCC will still show direct call
+instructions---look at the disassembled object code to see the actual
+instructions.  Note that the assembler will use an indirect call for
+every cross-file call, not just those that really will be out of range.
+@end table
+
+@node Code Gen Options
+@section Options for Code Generation Conventions
+@cindex code generation conventions
+@cindex options, code generation
+@cindex run-time options
+
+These machine-independent options control the interface conventions
+used in code generation.
+
+Most of them have both positive and negative forms; the negative form
+of @option{-ffoo} would be @option{-fno-foo}.  In the table below, only
+one of the forms is listed---the one which is not the default.  You
+can figure out the other form by either removing @samp{no-} or adding
+it.
+
+@table @gcctabopt
+@item -fexceptions
+@opindex fexceptions
+Enable exception handling.  Generates extra code needed to propagate
+exceptions.  For some targets, this implies GCC will generate frame
+unwind information for all functions, which can produce significant data
+size overhead, although it does not affect execution.  If you do not
+specify this option, GCC will enable it by default for languages like
+C++ which normally require exception handling, and disable it for
+languages like C that do not normally require it.  However, you may need
+to enable this option when compiling C code that needs to interoperate
+properly with exception handlers written in C++.  You may also wish to
+disable this option if you are compiling older C++ programs that don't
+use exception handling.
+
+@item -fnon-call-exceptions
+@opindex fnon-call-exceptions
+Generate code that allows trapping instructions to throw exceptions.
+Note that this requires platform-specific runtime support that does
+not exist everywhere.  Moreover, it only allows @emph{trapping}
+instructions to throw exceptions, i.e.@: memory references or floating
+point instructions.  It does not allow exceptions to be thrown from
+arbitrary signal handlers such as @code{SIGALRM}.
+
+@item -funwind-tables
+@opindex funwind-tables
+Similar to @option{-fexceptions}, except that it will just generate any needed
+static data, but will not affect the generated code in any other way.
+You will normally not enable this option; instead, a language processor
+that needs this handling would enable it on your behalf.
+
+@item -fasynchronous-unwind-tables
+@opindex funwind-tables
+Generate unwind table in dwarf2 format, if supported by target machine.  The
+table is exact at each instruction boundary, so it can be used for stack
+unwinding from asynchronous events (such as debugger or garbage collector).
+
+@item -fpcc-struct-return
+@opindex fpcc-struct-return
+Return ``short'' @code{struct} and @code{union} values in memory like
+longer ones, rather than in registers.  This convention is less
+efficient, but it has the advantage of allowing intercallability between
+GCC-compiled files and files compiled with other compilers.
+
+The precise convention for returning structures in memory depends
+on the target configuration macros.
+
+Short structures and unions are those whose size and alignment match
+that of some integer type.
+
+@item -freg-struct-return
+@opindex freg-struct-return
+Return @code{struct} and @code{union} values in registers when possible.
+This is more efficient for small structures than
+@option{-fpcc-struct-return}.
+
+If you specify neither @option{-fpcc-struct-return} nor
+@option{-freg-struct-return}, GCC defaults to whichever convention is
+standard for the target.  If there is no standard convention, GCC
+defaults to @option{-fpcc-struct-return}, except on targets where GCC is
+the principal compiler.  In those cases, we can choose the standard, and
+we chose the more efficient register return alternative.
+
+@item -fshort-enums
+@opindex fshort-enums
+Allocate to an @code{enum} type only as many bytes as it needs for the
+declared range of possible values.  Specifically, the @code{enum} type
+will be equivalent to the smallest integer type which has enough room.
+
+@item -fshort-double
+@opindex fshort-double
+Use the same size for @code{double} as for @code{float}.
+
+@item -fshared-data
+@opindex fshared-data
+Requests that the data and non-@code{const} variables of this
+compilation be shared data rather than private data.  The distinction
+makes sense only on certain operating systems, where shared data is
+shared between processes running the same program, while private data
+exists in one copy per process.
+
+@item -fno-common
+@opindex fno-common
+In C, allocate even uninitialized global variables in the data section of the
+object file, rather than generating them as common blocks.  This has the
+effect that if the same variable is declared (without @code{extern}) in
+two different compilations, you will get an error when you link them.
+The only reason this might be useful is if you wish to verify that the
+program will work on other systems which always work this way.
+
+@item -fno-ident
+@opindex fno-ident
+Ignore the @samp{#ident} directive.
+
+@item -fno-gnu-linker
+@opindex fno-gnu-linker
+Do not output global initializations (such as C++ constructors and
+destructors) in the form used by the GNU linker (on systems where the GNU
+linker is the standard method of handling them).  Use this option when
+you want to use a non-GNU linker, which also requires using the
+@command{collect2} program to make sure the system linker includes
+constructors and destructors.  (@command{collect2} is included in the GCC
+distribution.)  For systems which @emph{must} use @command{collect2}, the
+compiler driver @command{gcc} is configured to do this automatically.
+
+@item -finhibit-size-directive
+@opindex finhibit-size-directive
+Don't output a @code{.size} assembler directive, or anything else that
+would cause trouble if the function is split in the middle, and the
+two halves are placed at locations far apart in memory.  This option is
+used when compiling @file{crtstuff.c}; you should not need to use it
+for anything else.
+
+@item -fverbose-asm
+@opindex fverbose-asm
+Put extra commentary information in the generated assembly code to
+make it more readable.  This option is generally only of use to those
+who actually need to read the generated assembly code (perhaps while
+debugging the compiler itself).
+
+@option{-fno-verbose-asm}, the default, causes the
+extra information to be omitted and is useful when comparing two assembler
+files.
+
+@item -fvolatile
+@opindex fvolatile
+Consider all memory references through pointers to be volatile.
+
+@item -fvolatile-global
+@opindex fvolatile-global
+Consider all memory references to extern and global data items to
+be volatile.  GCC does not consider static data items to be volatile
+because of this switch.
+
+@item -fvolatile-static
+@opindex fvolatile-static
+Consider all memory references to static data to be volatile.
+
+@item -fpic
+@opindex fpic
+@cindex global offset table
+@cindex PIC
+Generate position-independent code (PIC) suitable for use in a shared
+library, if supported for the target machine.  Such code accesses all
+constant addresses through a global offset table (GOT)@.  The dynamic
+loader resolves the GOT entries when the program starts (the dynamic
+loader is not part of GCC; it is part of the operating system).  If
+the GOT size for the linked executable exceeds a machine-specific
+maximum size, you get an error message from the linker indicating that
+@option{-fpic} does not work; in that case, recompile with @option{-fPIC}
+instead.  (These maximums are 16k on the m88k, 8k on the Sparc, and 32k
+on the m68k and RS/6000.  The 386 has no such limit.)
+
+Position-independent code requires special support, and therefore works
+only on certain machines.  For the 386, GCC supports PIC for System V
+but not for the Sun 386i.  Code generated for the IBM RS/6000 is always
+position-independent.
+
+@item -fPIC
+@opindex fPIC
+If supported for the target machine, emit position-independent code,
+suitable for dynamic linking and avoiding any limit on the size of the
+global offset table.  This option makes a difference on the m68k, m88k,
+and the Sparc.
+
+Position-independent code requires special support, and therefore works
+only on certain machines.
+
+@item -ffixed-@var{reg}
+@opindex ffixed
+Treat the register named @var{reg} as a fixed register; generated code
+should never refer to it (except perhaps as a stack pointer, frame
+pointer or in some other fixed role).
+
+@var{reg} must be the name of a register.  The register names accepted
+are machine-specific and are defined in the @code{REGISTER_NAMES}
+macro in the machine description macro file.
+
+This flag does not have a negative form, because it specifies a
+three-way choice.
+
+@item -fcall-used-@var{reg}
+@opindex fcall-used
+Treat the register named @var{reg} as an allocable register that is
+clobbered by function calls.  It may be allocated for temporaries or
+variables that do not live across a call.  Functions compiled this way
+will not save and restore the register @var{reg}.
+
+It is an error to used this flag with the frame pointer or stack pointer.
+Use of this flag for other registers that have fixed pervasive roles in
+the machine's execution model will produce disastrous results.
+
+This flag does not have a negative form, because it specifies a
+three-way choice.
+
+@item -fcall-saved-@var{reg}
+@opindex fcall-saved
+Treat the register named @var{reg} as an allocable register saved by
+functions.  It may be allocated even for temporaries or variables that
+live across a call.  Functions compiled this way will save and restore
+the register @var{reg} if they use it.
+
+It is an error to used this flag with the frame pointer or stack pointer.
+Use of this flag for other registers that have fixed pervasive roles in
+the machine's execution model will produce disastrous results.
+
+A different sort of disaster will result from the use of this flag for
+a register in which function values may be returned.
+
+This flag does not have a negative form, because it specifies a
+three-way choice.
+
+@item -fpack-struct
+@opindex fpack-struct
+Pack all structure members together without holes.  Usually you would
+not want to use this option, since it makes the code suboptimal, and
+the offsets of structure members won't agree with system libraries.
+
+@item -finstrument-functions
+@opindex finstrument-functions
+Generate instrumentation calls for entry and exit to functions.  Just
+after function entry and just before function exit, the following
+profiling functions will be called with the address of the current
+function and its call site.  (On some platforms,
+@code{__builtin_return_address} does not work beyond the current
+function, so the call site information may not be available to the
+profiling functions otherwise.)
+
+@example
+void __cyg_profile_func_enter (void *this_fn,
+                               void *call_site);
+void __cyg_profile_func_exit  (void *this_fn,
+                               void *call_site);
+@end example
+
+The first argument is the address of the start of the current function,
+which may be looked up exactly in the symbol table.
+
+This instrumentation is also done for functions expanded inline in other
+functions.  The profiling calls will indicate where, conceptually, the
+inline function is entered and exited.  This means that addressable
+versions of such functions must be available.  If all your uses of a
+function are expanded inline, this may mean an additional expansion of
+code size.  If you use @samp{extern inline} in your C code, an
+addressable version of such functions must be provided.  (This is
+normally the case anyways, but if you get lucky and the optimizer always
+expands the functions inline, you might have gotten away without
+providing static copies.)
+
+A function may be given the attribute @code{no_instrument_function}, in
+which case this instrumentation will not be done.  This can be used, for
+example, for the profiling functions listed above, high-priority
+interrupt routines, and any functions from which the profiling functions
+cannot safely be called (perhaps signal handlers, if the profiling
+routines generate output or allocate memory).
+
+@item -fstack-check
+@opindex fstack-check
+Generate code to verify that you do not go beyond the boundary of the
+stack.  You should specify this flag if you are running in an
+environment with multiple threads, but only rarely need to specify it in
+a single-threaded environment since stack overflow is automatically
+detected on nearly all systems if there is only one stack.
+
+Note that this switch does not actually cause checking to be done; the
+operating system must do that.  The switch causes generation of code
+to ensure that the operating system sees the stack being extended.
+
+@item -fstack-limit-register=@var{reg}
+@itemx -fstack-limit-symbol=@var{sym}
+@itemx -fno-stack-limit
+@opindex fstack-limit-register
+@opindex fstack-limit-symbol
+@opindex fno-stack-limit
+Generate code to ensure that the stack does not grow beyond a certain value,
+either the value of a register or the address of a symbol.  If the stack
+would grow beyond the value, a signal is raised.  For most targets,
+the signal is raised before the stack overruns the boundary, so
+it is possible to catch the signal without taking special precautions.
+
+For instance, if the stack starts at absolute address @samp{0x80000000}
+and grows downwards, you can use the flags
+@option{-fstack-limit-symbol=__stack_limit} and
+@option{-Wl,--defsym,__stack_limit=0x7ffe0000} to enforce a stack limit
+of 128KB@.  Note that this may only work with the GNU linker.
+
+@cindex aliasing of parameters
+@cindex parameters, aliased
+@item -fargument-alias
+@itemx -fargument-noalias
+@itemx -fargument-noalias-global
+@opindex fargument-alias
+@opindex fargument-noalias
+@opindex fargument-noalias-global
+Specify the possible relationships among parameters and between
+parameters and global data.
+
+@option{-fargument-alias} specifies that arguments (parameters) may
+alias each other and may alias global storage.@*
+@option{-fargument-noalias} specifies that arguments do not alias
+each other, but may alias global storage.@*
+@option{-fargument-noalias-global} specifies that arguments do not
+alias each other and do not alias global storage.
+
+Each language will automatically use whatever option is required by
+the language standard.  You should not need to use these options yourself.
+
+@item -fleading-underscore
+@opindex fleading-underscore
+This option and its counterpart, @option{-fno-leading-underscore}, forcibly
+change the way C symbols are represented in the object file.  One use
+is to help link with legacy assembly code.
+
+Be warned that you should know what you are doing when invoking this
+option, and that not all targets provide complete support for it.
+@end table
+
+@c man end
+
+@node Environment Variables
+@section Environment Variables Affecting GCC
+@cindex environment variables
+
+@c man begin ENVIRONMENT
+
+This section describes several environment variables that affect how GCC
+operates.  Some of them work by specifying directories or prefixes to use
+when searching for various kinds of files.  Some are used to specify other
+aspects of the compilation environment.
+
+Note that you can also specify places to search using options such as
+@option{-B}, @option{-I} and @option{-L} (@pxref{Directory Options}).  These
+take precedence over places specified using environment variables, which
+in turn take precedence over those specified by the configuration of GCC@.
+@xref{Driver,, Controlling the Compilation Driver @file{gcc}, gccint,
+GNU Compiler Collection (GCC) Internals}.
+
+@table @env
+@item LANG
+@itemx LC_CTYPE
+@c @itemx LC_COLLATE
+@itemx LC_MESSAGES
+@c @itemx LC_MONETARY
+@c @itemx LC_NUMERIC
+@c @itemx LC_TIME
+@itemx LC_ALL
+@findex LANG
+@findex LC_CTYPE
+@c @findex LC_COLLATE
+@findex LC_MESSAGES
+@c @findex LC_MONETARY
+@c @findex LC_NUMERIC
+@c @findex LC_TIME
+@findex LC_ALL
+@cindex locale
+These environment variables control the way that GCC uses
+localization information that allow GCC to work with different
+national conventions.  GCC inspects the locale categories
+@env{LC_CTYPE} and @env{LC_MESSAGES} if it has been configured to do
+so.  These locale categories can be set to any value supported by your
+installation.  A typical value is @samp{en_UK} for English in the United
+Kingdom.
+
+The @env{LC_CTYPE} environment variable specifies character
+classification.  GCC uses it to determine the character boundaries in
+a string; this is needed for some multibyte encodings that contain quote
+and escape characters that would otherwise be interpreted as a string
+end or escape.
+
+The @env{LC_MESSAGES} environment variable specifies the language to
+use in diagnostic messages.
+
+If the @env{LC_ALL} environment variable is set, it overrides the value
+of @env{LC_CTYPE} and @env{LC_MESSAGES}; otherwise, @env{LC_CTYPE}
+and @env{LC_MESSAGES} default to the value of the @env{LANG}
+environment variable.  If none of these variables are set, GCC
+defaults to traditional C English behavior.
+
+@item TMPDIR
+@findex TMPDIR
+If @env{TMPDIR} is set, it specifies the directory to use for temporary
+files.  GCC uses temporary files to hold the output of one stage of
+compilation which is to be used as input to the next stage: for example,
+the output of the preprocessor, which is the input to the compiler
+proper.
+
+@item GCC_EXEC_PREFIX
+@findex GCC_EXEC_PREFIX
+If @env{GCC_EXEC_PREFIX} is set, it specifies a prefix to use in the
+names of the subprograms executed by the compiler.  No slash is added
+when this prefix is combined with the name of a subprogram, but you can
+specify a prefix that ends with a slash if you wish.
+
+If @env{GCC_EXEC_PREFIX} is not set, GCC will attempt to figure out
+an appropriate prefix to use based on the pathname it was invoked with.
+
+If GCC cannot find the subprogram using the specified prefix, it
+tries looking in the usual places for the subprogram.
+
+The default value of @env{GCC_EXEC_PREFIX} is
+@file{@var{prefix}/lib/gcc-lib/} where @var{prefix} is the value
+of @code{prefix} when you ran the @file{configure} script.
+
+Other prefixes specified with @option{-B} take precedence over this prefix.
+
+This prefix is also used for finding files such as @file{crt0.o} that are
+used for linking.
+
+In addition, the prefix is used in an unusual way in finding the
+directories to search for header files.  For each of the standard
+directories whose name normally begins with @samp{/usr/local/lib/gcc-lib}
+(more precisely, with the value of @env{GCC_INCLUDE_DIR}), GCC tries
+replacing that beginning with the specified prefix to produce an
+alternate directory name.  Thus, with @option{-Bfoo/}, GCC will search
+@file{foo/bar} where it would normally search @file{/usr/local/lib/bar}.
+These alternate directories are searched first; the standard directories
+come next.
+
+@item COMPILER_PATH
+@findex COMPILER_PATH
+The value of @env{COMPILER_PATH} is a colon-separated list of
+directories, much like @env{PATH}.  GCC tries the directories thus
+specified when searching for subprograms, if it can't find the
+subprograms using @env{GCC_EXEC_PREFIX}.
+
+@item LIBRARY_PATH
+@findex LIBRARY_PATH
+The value of @env{LIBRARY_PATH} is a colon-separated list of
+directories, much like @env{PATH}.  When configured as a native compiler,
+GCC tries the directories thus specified when searching for special
+linker files, if it can't find them using @env{GCC_EXEC_PREFIX}.  Linking
+using GCC also uses these directories when searching for ordinary
+libraries for the @option{-l} option (but directories specified with
+@option{-L} come first).
+
+@item C_INCLUDE_PATH
+@itemx CPLUS_INCLUDE_PATH
+@itemx OBJC_INCLUDE_PATH
+@findex C_INCLUDE_PATH
+@findex CPLUS_INCLUDE_PATH
+@findex OBJC_INCLUDE_PATH
+@c @itemx OBJCPLUS_INCLUDE_PATH
+These environment variables pertain to particular languages.  Each
+variable's value is a colon-separated list of directories, much like
+@env{PATH}.  When GCC searches for header files, it tries the
+directories listed in the variable for the language you are using, after
+the directories specified with @option{-I} but before the standard header
+file directories.
+
+@item DEPENDENCIES_OUTPUT
+@findex DEPENDENCIES_OUTPUT
+@cindex dependencies for make as output
+If this variable is set, its value specifies how to output dependencies
+for Make based on the header files processed by the compiler.  This
+output looks much like the output from the @option{-M} option
+(@pxref{Preprocessor Options}), but it goes to a separate file, and is
+in addition to the usual results of compilation.
+
+The value of @env{DEPENDENCIES_OUTPUT} can be just a file name, in
+which case the Make rules are written to that file, guessing the target
+name from the source file name.  Or the value can have the form
+@samp{@var{file} @var{target}}, in which case the rules are written to
+file @var{file} using @var{target} as the target name.
+
+@item LANG
+@findex LANG
+@cindex locale definition
+This variable is used to pass locale information to the compiler.  One way in
+which this information is used is to determine the character set to be used
+when character literals, string literals and comments are parsed in C and C++.
+When the compiler is configured to allow multibyte characters,
+the following values for @env{LANG} are recognized:
+
+@table @samp
+@item C-JIS
+Recognize JIS characters.
+@item C-SJIS
+Recognize SJIS characters.
+@item C-EUCJP
+Recognize EUCJP characters.
+@end table
+
+If @env{LANG} is not defined, or if it has some other value, then the
+compiler will use mblen and mbtowc as defined by the default locale to
+recognize and translate multibyte characters.
+@end table
+
+@c man end
+
+@node Running Protoize
+@section Running Protoize
+
+The program @code{protoize} is an optional part of GCC@.  You can use
+it to add prototypes to a program, thus converting the program to ISO
+C in one respect.  The companion program @code{unprotoize} does the
+reverse: it removes argument types from any prototypes that are found.
+
+When you run these programs, you must specify a set of source files as
+command line arguments.  The conversion programs start out by compiling
+these files to see what functions they define.  The information gathered
+about a file @var{foo} is saved in a file named @file{@var{foo}.X}.
+
+After scanning comes actual conversion.  The specified files are all
+eligible to be converted; any files they include (whether sources or
+just headers) are eligible as well.
+
+But not all the eligible files are converted.  By default,
+@code{protoize} and @code{unprotoize} convert only source and header
+files in the current directory.  You can specify additional directories
+whose files should be converted with the @option{-d @var{directory}}
+option.  You can also specify particular files to exclude with the
+@option{-x @var{file}} option.  A file is converted if it is eligible, its
+directory name matches one of the specified directory names, and its
+name within the directory has not been excluded.
+
+Basic conversion with @code{protoize} consists of rewriting most
+function definitions and function declarations to specify the types of
+the arguments.  The only ones not rewritten are those for varargs
+functions.
+
+@code{protoize} optionally inserts prototype declarations at the
+beginning of the source file, to make them available for any calls that
+precede the function's definition.  Or it can insert prototype
+declarations with block scope in the blocks where undeclared functions
+are called.
+
+Basic conversion with @code{unprotoize} consists of rewriting most
+function declarations to remove any argument types, and rewriting
+function definitions to the old-style pre-ISO form.
+
+Both conversion programs print a warning for any function declaration or
+definition that they can't convert.  You can suppress these warnings
+with @option{-q}.
+
+The output from @code{protoize} or @code{unprotoize} replaces the
+original source file.  The original file is renamed to a name ending
+with @samp{.save} (for DOS, the saved filename ends in @samp{.sav}
+without the original @samp{.c} suffix).  If the @samp{.save} (@samp{.sav}
+for DOS) file already exists, then the source file is simply discarded.
+
+@code{protoize} and @code{unprotoize} both depend on GCC itself to
+scan the program and collect information about the functions it uses.
+So neither of these programs will work until GCC is installed.
+
+Here is a table of the options you can use with @code{protoize} and
+@code{unprotoize}.  Each option works with both programs unless
+otherwise stated.
+
+@table @code
+@item -B @var{directory}
+Look for the file @file{SYSCALLS.c.X} in @var{directory}, instead of the
+usual directory (normally @file{/usr/local/lib}).  This file contains
+prototype information about standard system functions.  This option
+applies only to @code{protoize}.
+
+@item -c @var{compilation-options}
+Use  @var{compilation-options} as the options when running @code{gcc} to
+produce the @samp{.X} files.  The special option @option{-aux-info} is
+always passed in addition, to tell @code{gcc} to write a @samp{.X} file.
+
+Note that the compilation options must be given as a single argument to
+@code{protoize} or @code{unprotoize}.  If you want to specify several
+@code{gcc} options, you must quote the entire set of compilation options
+to make them a single word in the shell.
+
+There are certain @code{gcc} arguments that you cannot use, because they
+would produce the wrong kind of output.  These include @option{-g},
+@option{-O}, @option{-c}, @option{-S}, and @option{-o} If you include these in
+the @var{compilation-options}, they are ignored.
+
+@item -C
+Rename files to end in @samp{.C} (@samp{.cc} for DOS-based file
+systems) instead of @samp{.c}.  This is convenient if you are converting
+a C program to C++.  This option applies only to @code{protoize}.
+
+@item -g
+Add explicit global declarations.  This means inserting explicit
+declarations at the beginning of each source file for each function
+that is called in the file and was not declared.  These declarations
+precede the first function definition that contains a call to an
+undeclared function.  This option applies only to @code{protoize}.
+
+@item -i @var{string}
+Indent old-style parameter declarations with the string @var{string}.
+This option applies only to @code{protoize}.
+
+@code{unprotoize} converts prototyped function definitions to old-style
+function definitions, where the arguments are declared between the
+argument list and the initial @samp{@{}.  By default, @code{unprotoize}
+uses five spaces as the indentation.  If you want to indent with just
+one space instead, use @option{-i " "}.
+
+@item -k
+Keep the @samp{.X} files.  Normally, they are deleted after conversion
+is finished.
+
+@item -l
+Add explicit local declarations.  @code{protoize} with @option{-l} inserts
+a prototype declaration for each function in each block which calls the
+function without any declaration.  This option applies only to
+@code{protoize}.
+
+@item -n
+Make no real changes.  This mode just prints information about the conversions
+that would have been done without @option{-n}.
+
+@item -N
+Make no @samp{.save} files.  The original files are simply deleted.
+Use this option with caution.
+
+@item -p @var{program}
+Use the program @var{program} as the compiler.  Normally, the name
+@file{gcc} is used.
+
+@item -q
+Work quietly.  Most warnings are suppressed.
+
+@item -v
+Print the version number, just like @option{-v} for @code{gcc}.
+@end table
+
+If you need special compiler options to compile one of your program's
+source files, then you should generate that file's @samp{.X} file
+specially, by running @code{gcc} on that source file with the
+appropriate options and the option @option{-aux-info}.  Then run
+@code{protoize} on the entire set of files.  @code{protoize} will use
+the existing @samp{.X} file because it is newer than the source file.
+For example:
+
+@example
+gcc -Dfoo=bar file1.c -aux-info file1.X
+protoize *.c
+@end example
+
+@noindent
+You need to include the special files along with the rest in the
+@code{protoize} command, even though their @samp{.X} files already
+exist, because otherwise they won't get converted.
+
+@xref{Protoize Caveats}, for more information on how to use
+@code{protoize} successfully.
diff --git a/contrib/gcc/doc/languages.texi b/contrib/gcc/doc/languages.texi
new file mode 100644
index 0000000..514cb08
--- /dev/null
+++ b/contrib/gcc/doc/languages.texi
@@ -0,0 +1,36 @@
+@c Copyright (C) 2002 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Languages
+@chapter Language Front Ends in GCC
+
+The interface to front ends for languages in GCC, and in particular
+the @code{tree} structure (@pxref{Trees}), was initially designed for
+C, and many aspects of it are still somewhat biased towards C and
+C-like languages.  It is, however, reasonably well suited to other
+procedural languages, and front ends for many such languages have been
+written for GCC@.
+
+Writing a compiler as a front end for GCC, rather than compiling
+directly to assembler or generating C code which is then compiled by
+GCC, has several advantages:
+
+@itemize @bullet
+@item GCC front ends benefit from the support for many different
+target machines already present in GCC@.
+@item GCC front ends benefit from all the optimizations in GCC@.  Some
+of these, such as alias analysis, may work better when GCC is
+compiling directly from source code then when it is compiling from
+generated C code.
+@item Better debugging information is generated when compiling
+directly from source code than when going via intermediate generated C
+code.
+@end itemize
+
+Because of the advantages of writing a compiler as a GCC front end,
+GCC front ends have also been created for languages very different
+from those for which GCC was designed, such as the declarative
+logic/functional language Mercury.  For these reasons, it may also be
+useful to implement compilers created for specialized purposes (for
+example, as part of a research project) as GCC front ends.
diff --git a/contrib/gcc/doc/makefile.texi b/contrib/gcc/doc/makefile.texi
new file mode 100644
index 0000000..69d621b
--- /dev/null
+++ b/contrib/gcc/doc/makefile.texi
@@ -0,0 +1,102 @@
+@c Copyright (C) 2001, 2002 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Makefile
+@subsection Makefile Targets
+@cindex makefile targets
+@cindex targets, makefile
+
+@table @code
+@item all
+This is the default target.  Depending on what your build/host/target
+configuration is, it coordinates all the things that need to be built.
+
+@item doc
+Produce info-formatted documentation.  Also, @code{make dvi} is
+available for DVI-formatted documentation, and @code{make
+generated-manpages} to generate man pages.
+
+@item mostlyclean
+Delete the files made while building the compiler.
+
+@item clean
+That, and all the other files built by @code{make all}.
+
+@item distclean
+That, and all the files created by @code{configure}.
+
+@item extraclean
+That, and any temporary or intermediate files, like emacs backup files.
+
+@item maintainer-clean
+Distclean plus any file that can be generated from other files.  Note
+that additional tools may be required beyond what is normally needed to
+build gcc.
+
+@item install
+Installs gcc.
+
+@item uninstall
+Deletes installed files.
+
+@item check
+Run the testsuite.  This creates a @file{testsuite} subdirectory that
+has various @file{.sum} and @file{.log} files containing the results of
+the testing.  You can run subsets with, for example, @code{make check-gcc}.
+You can specify specific tests by setting RUNTESTFLAGS to be the name
+of the @file{.exp} file, optionally followed by (for some tests) an equals
+and a file wildcard, like:
+
+@example
+make check-gcc RUNTESTFLAGS="execute.exp=19980413-*"
+@end example
+
+Note that running the testsuite may require additional tools be
+installed, such as TCL or dejagnu.
+
+@item bootstrap
+Builds gcc three times---once with the native compiler, once with the
+native-built compiler it just built, and once with the compiler it built
+the second time.  In theory, the last two should produce the same
+results, which @code{make compare} can check.  Each step of this process
+is called a ``stage'', and the results of each stage @var{N}
+(@var{N} = 1@dots{}3) are copied to a subdirectory @file{stage@var{N}/}.
+
+@item bootstrap-lean
+Like @code{bootstrap}, except that the various stages are removed once
+they're no longer needed.  This saves disk space.
+
+@item bubblestrap
+Once bootstrapped, this incrementally rebuilds each of the three stages,
+one at a time.  It does this by ``bubbling'' the stages up from their
+subdirectories, rebuilding them, and copying them back to their
+subdirectories.  This will allow you to, for example, quickly rebuild a
+bootstrapped compiler after changing the sources, without having to do a
+full bootstrap.
+
+@item quickstrap
+Rebuilds the most recently built stage.  Since each stage requires
+special invocation, using this target means you don't have to keep track
+of which stage you're on or what invocation that stage needs.
+
+@item cleanstrap
+Removed everything (@code{make clean}) and rebuilds (@code{make bootstrap}).
+
+@item stage@var{N} (@var{N} = 1@dots{}4)
+For each stage, moves the appropriate files to the @file{stage@var{N}}
+subdirectory.
+
+@item unstage@var{N} (@var{N} = 1@dots{}4)
+Undoes the corresponding @code{stage@var{N}}.
+
+@item restage@var{N} (@var{N} = 1@dots{}4)
+Undoes the corresponding @code{stage@var{N}} and rebuilds it with the
+appropriate flags.
+
+@item compare
+Compares the results of stages 2 and 3.  This ensures that the compiler
+is running properly, since it should produce the same object files
+regardless of how it itself was compiled.
+
+@end table
diff --git a/contrib/gcc/doc/md.texi b/contrib/gcc/doc/md.texi
new file mode 100644
index 0000000..ca59a6c
--- /dev/null
+++ b/contrib/gcc/doc/md.texi
@@ -0,0 +1,5303 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1996, 1998, 1999, 2000, 2001, 2002
+@c Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@ifset INTERNALS
+@node Machine Desc
+@chapter Machine Descriptions
+@cindex machine descriptions
+
+A machine description has two parts: a file of instruction patterns
+(@file{.md} file) and a C header file of macro definitions.
+
+The @file{.md} file for a target machine contains a pattern for each
+instruction that the target machine supports (or at least each instruction
+that is worth telling the compiler about).  It may also contain comments.
+A semicolon causes the rest of the line to be a comment, unless the semicolon
+is inside a quoted string.
+
+See the next chapter for information on the C header file.
+
+@menu
+* Overview::            How the machine description is used.
+* Patterns::            How to write instruction patterns.
+* Example::             An explained example of a @code{define_insn} pattern.
+* RTL Template::        The RTL template defines what insns match a pattern.
+* Output Template::     The output template says how to make assembler code
+                          from such an insn.
+* Output Statement::    For more generality, write C code to output
+                          the assembler code.
+* Constraints::         When not all operands are general operands.
+* Standard Names::      Names mark patterns to use for code generation.
+* Pattern Ordering::    When the order of patterns makes a difference.
+* Dependent Patterns::  Having one pattern may make you need another.
+* Jump Patterns::       Special considerations for patterns for jump insns.
+* Looping Patterns::    How to define patterns for special looping insns.
+* Insn Canonicalizations::Canonicalization of Instructions
+* Expander Definitions::Generating a sequence of several RTL insns
+                          for a standard operation.
+* Insn Splitting::      Splitting Instructions into Multiple Instructions.
+* Including Patterns::      Including Patterns in Machine Descriptions.
+* Peephole Definitions::Defining machine-specific peephole optimizations.
+* Insn Attributes::     Specifying the value of attributes for generated insns.
+* Conditional Execution::Generating @code{define_insn} patterns for
+                           predication.
+* Constant Definitions::Defining symbolic constants that can be used in the
+                        md file.
+@end menu
+
+@node Overview
+@section Overview of How the Machine Description is Used
+
+There are three main conversions that happen in the compiler:
+
+@enumerate
+
+@item
+The front end reads the source code and builds a parse tree.
+
+@item
+The parse tree is used to generate an RTL insn list based on named
+instruction patterns.
+
+@item
+The insn list is matched against the RTL templates to produce assembler
+code.
+
+@end enumerate
+
+For the generate pass, only the names of the insns matter, from either a
+named @code{define_insn} or a @code{define_expand}.  The compiler will
+choose the pattern with the right name and apply the operands according
+to the documentation later in this chapter, without regard for the RTL
+template or operand constraints.  Note that the names the compiler looks
+for are hard-coded in the compiler---it will ignore unnamed patterns and
+patterns with names it doesn't know about, but if you don't provide a
+named pattern it needs, it will abort.
+
+If a @code{define_insn} is used, the template given is inserted into the
+insn list.  If a @code{define_expand} is used, one of three things
+happens, based on the condition logic.  The condition logic may manually
+create new insns for the insn list, say via @code{emit_insn()}, and
+invoke @code{DONE}.  For certain named patterns, it may invoke @code{FAIL} to tell the
+compiler to use an alternate way of performing that task.  If it invokes
+neither @code{DONE} nor @code{FAIL}, the template given in the pattern
+is inserted, as if the @code{define_expand} were a @code{define_insn}.
+
+Once the insn list is generated, various optimization passes convert,
+replace, and rearrange the insns in the insn list.  This is where the
+@code{define_split} and @code{define_peephole} patterns get used, for
+example.
+
+Finally, the insn list's RTL is matched up with the RTL templates in the
+@code{define_insn} patterns, and those patterns are used to emit the
+final assembly code.  For this purpose, each named @code{define_insn}
+acts like it's unnamed, since the names are ignored.
+
+@node Patterns
+@section Everything about Instruction Patterns
+@cindex patterns
+@cindex instruction patterns
+
+@findex define_insn
+Each instruction pattern contains an incomplete RTL expression, with pieces
+to be filled in later, operand constraints that restrict how the pieces can
+be filled in, and an output pattern or C code to generate the assembler
+output, all wrapped up in a @code{define_insn} expression.
+
+A @code{define_insn} is an RTL expression containing four or five operands:
+
+@enumerate
+@item
+An optional name.  The presence of a name indicate that this instruction
+pattern can perform a certain standard job for the RTL-generation
+pass of the compiler.  This pass knows certain names and will use
+the instruction patterns with those names, if the names are defined
+in the machine description.
+
+The absence of a name is indicated by writing an empty string
+where the name should go.  Nameless instruction patterns are never
+used for generating RTL code, but they may permit several simpler insns
+to be combined later on.
+
+Names that are not thus known and used in RTL-generation have no
+effect; they are equivalent to no name at all.
+
+For the purpose of debugging the compiler, you may also specify a
+name beginning with the @samp{*} character.  Such a name is used only
+for identifying the instruction in RTL dumps; it is entirely equivalent
+to having a nameless pattern for all other purposes.
+
+@item
+The @dfn{RTL template} (@pxref{RTL Template}) is a vector of incomplete
+RTL expressions which show what the instruction should look like.  It is
+incomplete because it may contain @code{match_operand},
+@code{match_operator}, and @code{match_dup} expressions that stand for
+operands of the instruction.
+
+If the vector has only one element, that element is the template for the
+instruction pattern.  If the vector has multiple elements, then the
+instruction pattern is a @code{parallel} expression containing the
+elements described.
+
+@item
+@cindex pattern conditions
+@cindex conditions, in patterns
+A condition.  This is a string which contains a C expression that is
+the final test to decide whether an insn body matches this pattern.
+
+@cindex named patterns and conditions
+For a named pattern, the condition (if present) may not depend on
+the data in the insn being matched, but only the target-machine-type
+flags.  The compiler needs to test these conditions during
+initialization in order to learn exactly which named instructions are
+available in a particular run.
+
+@findex operands
+For nameless patterns, the condition is applied only when matching an
+individual insn, and only after the insn has matched the pattern's
+recognition template.  The insn's operands may be found in the vector
+@code{operands}.
+
+@item
+The @dfn{output template}: a string that says how to output matching
+insns as assembler code.  @samp{%} in this string specifies where
+to substitute the value of an operand.  @xref{Output Template}.
+
+When simple substitution isn't general enough, you can specify a piece
+of C code to compute the output.  @xref{Output Statement}.
+
+@item
+Optionally, a vector containing the values of attributes for insns matching
+this pattern.  @xref{Insn Attributes}.
+@end enumerate
+
+@node Example
+@section Example of @code{define_insn}
+@cindex @code{define_insn} example
+
+Here is an actual example of an instruction pattern, for the 68000/68020.
+
+@example
+(define_insn "tstsi"
+  [(set (cc0)
+        (match_operand:SI 0 "general_operand" "rm"))]
+  ""
+  "*
+@{ 
+  if (TARGET_68020 || ! ADDRESS_REG_P (operands[0]))
+    return \"tstl %0\";
+  return \"cmpl #0,%0\"; 
+@}")
+@end example
+
+@noindent
+This can also be written using braced strings:
+
+@example
+(define_insn "tstsi"
+  [(set (cc0)
+        (match_operand:SI 0 "general_operand" "rm"))]
+  ""
+@{ 
+  if (TARGET_68020 || ! ADDRESS_REG_P (operands[0]))
+    return "tstl %0";
+  return "cmpl #0,%0"; 
+@})
+@end example
+
+This is an instruction that sets the condition codes based on the value of
+a general operand.  It has no condition, so any insn whose RTL description
+has the form shown may be handled according to this pattern.  The name
+@samp{tstsi} means ``test a @code{SImode} value'' and tells the RTL generation
+pass that, when it is necessary to test such a value, an insn to do so
+can be constructed using this pattern.
+
+The output control string is a piece of C code which chooses which
+output template to return based on the kind of operand and the specific
+type of CPU for which code is being generated.
+
+@samp{"rm"} is an operand constraint.  Its meaning is explained below.
+
+@node RTL Template
+@section RTL Template
+@cindex RTL insn template
+@cindex generating insns
+@cindex insns, generating
+@cindex recognizing insns
+@cindex insns, recognizing
+
+The RTL template is used to define which insns match the particular pattern
+and how to find their operands.  For named patterns, the RTL template also
+says how to construct an insn from specified operands.
+
+Construction involves substituting specified operands into a copy of the
+template.  Matching involves determining the values that serve as the
+operands in the insn being matched.  Both of these activities are
+controlled by special expression types that direct matching and
+substitution of the operands.
+
+@table @code
+@findex match_operand
+@item (match_operand:@var{m} @var{n} @var{predicate} @var{constraint})
+This expression is a placeholder for operand number @var{n} of
+the insn.  When constructing an insn, operand number @var{n}
+will be substituted at this point.  When matching an insn, whatever
+appears at this position in the insn will be taken as operand
+number @var{n}; but it must satisfy @var{predicate} or this instruction
+pattern will not match at all.
+
+Operand numbers must be chosen consecutively counting from zero in
+each instruction pattern.  There may be only one @code{match_operand}
+expression in the pattern for each operand number.  Usually operands
+are numbered in the order of appearance in @code{match_operand}
+expressions.  In the case of a @code{define_expand}, any operand numbers
+used only in @code{match_dup} expressions have higher values than all
+other operand numbers.
+
+@var{predicate} is a string that is the name of a C function that accepts two
+arguments, an expression and a machine mode.  During matching, the
+function will be called with the putative operand as the expression and
+@var{m} as the mode argument (if @var{m} is not specified,
+@code{VOIDmode} will be used, which normally causes @var{predicate} to accept
+any mode).  If it returns zero, this instruction pattern fails to match.
+@var{predicate} may be an empty string; then it means no test is to be done
+on the operand, so anything which occurs in this position is valid.
+
+Most of the time, @var{predicate} will reject modes other than @var{m}---but
+not always.  For example, the predicate @code{address_operand} uses
+@var{m} as the mode of memory ref that the address should be valid for.
+Many predicates accept @code{const_int} nodes even though their mode is
+@code{VOIDmode}.
+
+@var{constraint} controls reloading and the choice of the best register
+class to use for a value, as explained later (@pxref{Constraints}).
+
+People are often unclear on the difference between the constraint and the
+predicate.  The predicate helps decide whether a given insn matches the
+pattern.  The constraint plays no role in this decision; instead, it
+controls various decisions in the case of an insn which does match.
+
+@findex general_operand
+On CISC machines, the most common @var{predicate} is
+@code{"general_operand"}.  This function checks that the putative
+operand is either a constant, a register or a memory reference, and that
+it is valid for mode @var{m}.
+
+@findex register_operand
+For an operand that must be a register, @var{predicate} should be
+@code{"register_operand"}.  Using @code{"general_operand"} would be
+valid, since the reload pass would copy any non-register operands
+through registers, but this would make GCC do extra work, it would
+prevent invariant operands (such as constant) from being removed from
+loops, and it would prevent the register allocator from doing the best
+possible job.  On RISC machines, it is usually most efficient to allow
+@var{predicate} to accept only objects that the constraints allow.
+
+@findex immediate_operand
+For an operand that must be a constant, you must be sure to either use
+@code{"immediate_operand"} for @var{predicate}, or make the instruction
+pattern's extra condition require a constant, or both.  You cannot
+expect the constraints to do this work!  If the constraints allow only
+constants, but the predicate allows something else, the compiler will
+crash when that case arises.
+
+@findex match_scratch
+@item (match_scratch:@var{m} @var{n} @var{constraint})
+This expression is also a placeholder for operand number @var{n}
+and indicates that operand must be a @code{scratch} or @code{reg}
+expression.
+
+When matching patterns, this is equivalent to
+
+@smallexample
+(match_operand:@var{m} @var{n} "scratch_operand" @var{pred})
+@end smallexample
+
+but, when generating RTL, it produces a (@code{scratch}:@var{m})
+expression.
+
+If the last few expressions in a @code{parallel} are @code{clobber}
+expressions whose operands are either a hard register or
+@code{match_scratch}, the combiner can add or delete them when
+necessary.  @xref{Side Effects}.
+
+@findex match_dup
+@item (match_dup @var{n})
+This expression is also a placeholder for operand number @var{n}.
+It is used when the operand needs to appear more than once in the
+insn.
+
+In construction, @code{match_dup} acts just like @code{match_operand}:
+the operand is substituted into the insn being constructed.  But in
+matching, @code{match_dup} behaves differently.  It assumes that operand
+number @var{n} has already been determined by a @code{match_operand}
+appearing earlier in the recognition template, and it matches only an
+identical-looking expression.
+
+Note that @code{match_dup} should not be used to tell the compiler that
+a particular register is being used for two operands (example:
+@code{add} that adds one register to another; the second register is
+both an input operand and the output operand).  Use a matching
+constraint (@pxref{Simple Constraints}) for those.  @code{match_dup} is for the cases where one
+operand is used in two places in the template, such as an instruction
+that computes both a quotient and a remainder, where the opcode takes
+two input operands but the RTL template has to refer to each of those
+twice; once for the quotient pattern and once for the remainder pattern.
+
+@findex match_operator
+@item (match_operator:@var{m} @var{n} @var{predicate} [@var{operands}@dots{}])
+This pattern is a kind of placeholder for a variable RTL expression
+code.
+
+When constructing an insn, it stands for an RTL expression whose
+expression code is taken from that of operand @var{n}, and whose
+operands are constructed from the patterns @var{operands}.
+
+When matching an expression, it matches an expression if the function
+@var{predicate} returns nonzero on that expression @emph{and} the
+patterns @var{operands} match the operands of the expression.
+
+Suppose that the function @code{commutative_operator} is defined as
+follows, to match any expression whose operator is one of the
+commutative arithmetic operators of RTL and whose mode is @var{mode}:
+
+@smallexample
+int
+commutative_operator (x, mode)
+     rtx x;
+     enum machine_mode mode;
+@{
+  enum rtx_code code = GET_CODE (x);
+  if (GET_MODE (x) != mode)
+    return 0;
+  return (GET_RTX_CLASS (code) == 'c'
+          || code == EQ || code == NE);
+@}
+@end smallexample
+
+Then the following pattern will match any RTL expression consisting
+of a commutative operator applied to two general operands:
+
+@smallexample
+(match_operator:SI 3 "commutative_operator"
+  [(match_operand:SI 1 "general_operand" "g")
+   (match_operand:SI 2 "general_operand" "g")])
+@end smallexample
+
+Here the vector @code{[@var{operands}@dots{}]} contains two patterns
+because the expressions to be matched all contain two operands.
+
+When this pattern does match, the two operands of the commutative
+operator are recorded as operands 1 and 2 of the insn.  (This is done
+by the two instances of @code{match_operand}.)  Operand 3 of the insn
+will be the entire commutative expression: use @code{GET_CODE
+(operands[3])} to see which commutative operator was used.
+
+The machine mode @var{m} of @code{match_operator} works like that of
+@code{match_operand}: it is passed as the second argument to the
+predicate function, and that function is solely responsible for
+deciding whether the expression to be matched ``has'' that mode.
+
+When constructing an insn, argument 3 of the gen-function will specify
+the operation (i.e.@: the expression code) for the expression to be
+made.  It should be an RTL expression, whose expression code is copied
+into a new expression whose operands are arguments 1 and 2 of the
+gen-function.  The subexpressions of argument 3 are not used;
+only its expression code matters.
+
+When @code{match_operator} is used in a pattern for matching an insn,
+it usually best if the operand number of the @code{match_operator}
+is higher than that of the actual operands of the insn.  This improves
+register allocation because the register allocator often looks at
+operands 1 and 2 of insns to see if it can do register tying.
+
+There is no way to specify constraints in @code{match_operator}.  The
+operand of the insn which corresponds to the @code{match_operator}
+never has any constraints because it is never reloaded as a whole.
+However, if parts of its @var{operands} are matched by
+@code{match_operand} patterns, those parts may have constraints of
+their own.
+
+@findex match_op_dup
+@item (match_op_dup:@var{m} @var{n}[@var{operands}@dots{}])
+Like @code{match_dup}, except that it applies to operators instead of
+operands.  When constructing an insn, operand number @var{n} will be
+substituted at this point.  But in matching, @code{match_op_dup} behaves
+differently.  It assumes that operand number @var{n} has already been
+determined by a @code{match_operator} appearing earlier in the
+recognition template, and it matches only an identical-looking
+expression.
+
+@findex match_parallel
+@item (match_parallel @var{n} @var{predicate} [@var{subpat}@dots{}])
+This pattern is a placeholder for an insn that consists of a
+@code{parallel} expression with a variable number of elements.  This
+expression should only appear at the top level of an insn pattern.
+
+When constructing an insn, operand number @var{n} will be substituted at
+this point.  When matching an insn, it matches if the body of the insn
+is a @code{parallel} expression with at least as many elements as the
+vector of @var{subpat} expressions in the @code{match_parallel}, if each
+@var{subpat} matches the corresponding element of the @code{parallel},
+@emph{and} the function @var{predicate} returns nonzero on the
+@code{parallel} that is the body of the insn.  It is the responsibility
+of the predicate to validate elements of the @code{parallel} beyond
+those listed in the @code{match_parallel}.
+
+A typical use of @code{match_parallel} is to match load and store
+multiple expressions, which can contain a variable number of elements
+in a @code{parallel}.  For example,
+
+@smallexample
+(define_insn ""
+  [(match_parallel 0 "load_multiple_operation"
+     [(set (match_operand:SI 1 "gpc_reg_operand" "=r")
+           (match_operand:SI 2 "memory_operand" "m"))
+      (use (reg:SI 179))
+      (clobber (reg:SI 179))])]
+  ""
+  "loadm 0,0,%1,%2")
+@end smallexample
+
+This example comes from @file{a29k.md}.  The function
+@code{load_multiple_operation} is defined in @file{a29k.c} and checks
+that subsequent elements in the @code{parallel} are the same as the
+@code{set} in the pattern, except that they are referencing subsequent
+registers and memory locations.
+
+An insn that matches this pattern might look like:
+
+@smallexample
+(parallel
+ [(set (reg:SI 20) (mem:SI (reg:SI 100)))
+  (use (reg:SI 179))
+  (clobber (reg:SI 179))
+  (set (reg:SI 21)
+       (mem:SI (plus:SI (reg:SI 100)
+                        (const_int 4))))
+  (set (reg:SI 22)
+       (mem:SI (plus:SI (reg:SI 100)
+                        (const_int 8))))])
+@end smallexample
+
+@findex match_par_dup
+@item (match_par_dup @var{n} [@var{subpat}@dots{}])
+Like @code{match_op_dup}, but for @code{match_parallel} instead of
+@code{match_operator}.
+
+@findex match_insn
+@item (match_insn @var{predicate})
+Match a complete insn.  Unlike the other @code{match_*} recognizers,
+@code{match_insn} does not take an operand number.
+
+The machine mode @var{m} of @code{match_insn} works like that of
+@code{match_operand}: it is passed as the second argument to the
+predicate function, and that function is solely responsible for
+deciding whether the expression to be matched ``has'' that mode.
+
+@findex match_insn2
+@item (match_insn2 @var{n} @var{predicate})
+Match a complete insn.
+
+The machine mode @var{m} of @code{match_insn2} works like that of
+@code{match_operand}: it is passed as the second argument to the
+predicate function, and that function is solely responsible for
+deciding whether the expression to be matched ``has'' that mode.
+
+@end table
+
+@node Output Template
+@section Output Templates and Operand Substitution
+@cindex output templates
+@cindex operand substitution
+
+@cindex @samp{%} in template
+@cindex percent sign
+The @dfn{output template} is a string which specifies how to output the
+assembler code for an instruction pattern.  Most of the template is a
+fixed string which is output literally.  The character @samp{%} is used
+to specify where to substitute an operand; it can also be used to
+identify places where different variants of the assembler require
+different syntax.
+
+In the simplest case, a @samp{%} followed by a digit @var{n} says to output
+operand @var{n} at that point in the string.
+
+@samp{%} followed by a letter and a digit says to output an operand in an
+alternate fashion.  Four letters have standard, built-in meanings described
+below.  The machine description macro @code{PRINT_OPERAND} can define
+additional letters with nonstandard meanings.
+
+@samp{%c@var{digit}} can be used to substitute an operand that is a
+constant value without the syntax that normally indicates an immediate
+operand.
+
+@samp{%n@var{digit}} is like @samp{%c@var{digit}} except that the value of
+the constant is negated before printing.
+
+@samp{%a@var{digit}} can be used to substitute an operand as if it were a
+memory reference, with the actual operand treated as the address.  This may
+be useful when outputting a ``load address'' instruction, because often the
+assembler syntax for such an instruction requires you to write the operand
+as if it were a memory reference.
+
+@samp{%l@var{digit}} is used to substitute a @code{label_ref} into a jump
+instruction.
+
+@samp{%=} outputs a number which is unique to each instruction in the
+entire compilation.  This is useful for making local labels to be
+referred to more than once in a single template that generates multiple
+assembler instructions.
+
+@samp{%} followed by a punctuation character specifies a substitution that
+does not use an operand.  Only one case is standard: @samp{%%} outputs a
+@samp{%} into the assembler code.  Other nonstandard cases can be
+defined in the @code{PRINT_OPERAND} macro.  You must also define
+which punctuation characters are valid with the
+@code{PRINT_OPERAND_PUNCT_VALID_P} macro.
+
+@cindex \
+@cindex backslash
+The template may generate multiple assembler instructions.  Write the text
+for the instructions, with @samp{\;} between them.
+
+@cindex matching operands
+When the RTL contains two operands which are required by constraint to match
+each other, the output template must refer only to the lower-numbered operand.
+Matching operands are not always identical, and the rest of the compiler
+arranges to put the proper RTL expression for printing into the lower-numbered
+operand.
+
+One use of nonstandard letters or punctuation following @samp{%} is to
+distinguish between different assembler languages for the same machine; for
+example, Motorola syntax versus MIT syntax for the 68000.  Motorola syntax
+requires periods in most opcode names, while MIT syntax does not.  For
+example, the opcode @samp{movel} in MIT syntax is @samp{move.l} in Motorola
+syntax.  The same file of patterns is used for both kinds of output syntax,
+but the character sequence @samp{%.} is used in each place where Motorola
+syntax wants a period.  The @code{PRINT_OPERAND} macro for Motorola syntax
+defines the sequence to output a period; the macro for MIT syntax defines
+it to do nothing.
+
+@cindex @code{#} in template
+As a special case, a template consisting of the single character @code{#}
+instructs the compiler to first split the insn, and then output the
+resulting instructions separately.  This helps eliminate redundancy in the
+output templates.   If you have a @code{define_insn} that needs to emit
+multiple assembler instructions, and there is an matching @code{define_split}
+already defined, then you can simply use @code{#} as the output template
+instead of writing an output template that emits the multiple assembler
+instructions.
+
+If the macro @code{ASSEMBLER_DIALECT} is defined, you can use construct
+of the form @samp{@{option0|option1|option2@}} in the templates.  These
+describe multiple variants of assembler language syntax.
+@xref{Instruction Output}.
+
+@node Output Statement
+@section C Statements for Assembler Output
+@cindex output statements
+@cindex C statements for assembler output
+@cindex generating assembler output
+
+Often a single fixed template string cannot produce correct and efficient
+assembler code for all the cases that are recognized by a single
+instruction pattern.  For example, the opcodes may depend on the kinds of
+operands; or some unfortunate combinations of operands may require extra
+machine instructions.
+
+If the output control string starts with a @samp{@@}, then it is actually
+a series of templates, each on a separate line.  (Blank lines and
+leading spaces and tabs are ignored.)  The templates correspond to the
+pattern's constraint alternatives (@pxref{Multi-Alternative}).  For example,
+if a target machine has a two-address add instruction @samp{addr} to add
+into a register and another @samp{addm} to add a register to memory, you
+might write this pattern:
+
+@smallexample
+(define_insn "addsi3"
+  [(set (match_operand:SI 0 "general_operand" "=r,m")
+        (plus:SI (match_operand:SI 1 "general_operand" "0,0")
+                 (match_operand:SI 2 "general_operand" "g,r")))]
+  ""
+  "@@
+   addr %2,%0
+   addm %2,%0")
+@end smallexample
+
+@cindex @code{*} in template
+@cindex asterisk in template
+If the output control string starts with a @samp{*}, then it is not an
+output template but rather a piece of C program that should compute a
+template.  It should execute a @code{return} statement to return the
+template-string you want.  Most such templates use C string literals, which
+require doublequote characters to delimit them.  To include these
+doublequote characters in the string, prefix each one with @samp{\}.
+
+If the output control string is written as a brace block instead of a
+double-quoted string, it is automatically assumed to be C code.  In that
+case, it is not necessary to put in a leading asterisk, or to escape the
+doublequotes surrounding C string literals.
+
+The operands may be found in the array @code{operands}, whose C data type
+is @code{rtx []}.
+
+It is very common to select different ways of generating assembler code
+based on whether an immediate operand is within a certain range.  Be
+careful when doing this, because the result of @code{INTVAL} is an
+integer on the host machine.  If the host machine has more bits in an
+@code{int} than the target machine has in the mode in which the constant
+will be used, then some of the bits you get from @code{INTVAL} will be
+superfluous.  For proper results, you must carefully disregard the
+values of those bits.
+
+@findex output_asm_insn
+It is possible to output an assembler instruction and then go on to output
+or compute more of them, using the subroutine @code{output_asm_insn}.  This
+receives two arguments: a template-string and a vector of operands.  The
+vector may be @code{operands}, or it may be another array of @code{rtx}
+that you declare locally and initialize yourself.
+
+@findex which_alternative
+When an insn pattern has multiple alternatives in its constraints, often
+the appearance of the assembler code is determined mostly by which alternative
+was matched.  When this is so, the C code can test the variable
+@code{which_alternative}, which is the ordinal number of the alternative
+that was actually satisfied (0 for the first, 1 for the second alternative,
+etc.).
+
+For example, suppose there are two opcodes for storing zero, @samp{clrreg}
+for registers and @samp{clrmem} for memory locations.  Here is how
+a pattern could use @code{which_alternative} to choose between them:
+
+@smallexample
+(define_insn ""
+  [(set (match_operand:SI 0 "general_operand" "=r,m")
+        (const_int 0))]
+  ""
+  @{
+  return (which_alternative == 0
+          ? "clrreg %0" : "clrmem %0");
+  @})
+@end smallexample
+
+The example above, where the assembler code to generate was
+@emph{solely} determined by the alternative, could also have been specified
+as follows, having the output control string start with a @samp{@@}:
+
+@smallexample
+@group
+(define_insn ""
+  [(set (match_operand:SI 0 "general_operand" "=r,m")
+        (const_int 0))]
+  ""
+  "@@
+   clrreg %0
+   clrmem %0")
+@end group
+@end smallexample
+@end ifset
+
+@c Most of this node appears by itself (in a different place) even
+@c when the INTERNALS flag is clear.  Passages that require the internals
+@c manual's context are conditionalized to appear only in the internals manual.
+@ifset INTERNALS
+@node Constraints
+@section Operand Constraints
+@cindex operand constraints
+@cindex constraints
+
+Each @code{match_operand} in an instruction pattern can specify a
+constraint for the type of operands allowed.
+@end ifset
+@ifclear INTERNALS
+@node Constraints
+@section Constraints for @code{asm} Operands
+@cindex operand constraints, @code{asm}
+@cindex constraints, @code{asm}
+@cindex @code{asm} constraints
+
+Here are specific details on what constraint letters you can use with
+@code{asm} operands.
+@end ifclear
+Constraints can say whether
+an operand may be in a register, and which kinds of register; whether the
+operand can be a memory reference, and which kinds of address; whether the
+operand may be an immediate constant, and which possible values it may
+have.  Constraints can also require two operands to match.
+
+@ifset INTERNALS
+@menu
+* Simple Constraints::  Basic use of constraints.
+* Multi-Alternative::   When an insn has two alternative constraint-patterns.
+* Class Preferences::   Constraints guide which hard register to put things in.
+* Modifiers::           More precise control over effects of constraints.
+* Machine Constraints:: Existing constraints for some particular machines.
+@end menu
+@end ifset
+
+@ifclear INTERNALS
+@menu
+* Simple Constraints::  Basic use of constraints.
+* Multi-Alternative::   When an insn has two alternative constraint-patterns.
+* Modifiers::           More precise control over effects of constraints.
+* Machine Constraints:: Special constraints for some particular machines.
+@end menu
+@end ifclear
+
+@node Simple Constraints
+@subsection Simple Constraints
+@cindex simple constraints
+
+The simplest kind of constraint is a string full of letters, each of
+which describes one kind of operand that is permitted.  Here are
+the letters that are allowed:
+
+@table @asis
+@item whitespace
+Whitespace characters are ignored and can be inserted at any position
+except the first.  This enables each alternative for different operands to
+be visually aligned in the machine description even if they have different
+number of constraints and modifiers.
+
+@cindex @samp{m} in constraint
+@cindex memory references in constraints
+@item @samp{m}
+A memory operand is allowed, with any kind of address that the machine
+supports in general.
+
+@cindex offsettable address
+@cindex @samp{o} in constraint
+@item @samp{o}
+A memory operand is allowed, but only if the address is
+@dfn{offsettable}.  This means that adding a small integer (actually,
+the width in bytes of the operand, as determined by its machine mode)
+may be added to the address and the result is also a valid memory
+address.
+
+@cindex autoincrement/decrement addressing
+For example, an address which is constant is offsettable; so is an
+address that is the sum of a register and a constant (as long as a
+slightly larger constant is also within the range of address-offsets
+supported by the machine); but an autoincrement or autodecrement
+address is not offsettable.  More complicated indirect/indexed
+addresses may or may not be offsettable depending on the other
+addressing modes that the machine supports.
+
+Note that in an output operand which can be matched by another
+operand, the constraint letter @samp{o} is valid only when accompanied
+by both @samp{<} (if the target machine has predecrement addressing)
+and @samp{>} (if the target machine has preincrement addressing).
+
+@cindex @samp{V} in constraint
+@item @samp{V}
+A memory operand that is not offsettable.  In other words, anything that
+would fit the @samp{m} constraint but not the @samp{o} constraint.
+
+@cindex @samp{<} in constraint
+@item @samp{<}
+A memory operand with autodecrement addressing (either predecrement or
+postdecrement) is allowed.
+
+@cindex @samp{>} in constraint
+@item @samp{>}
+A memory operand with autoincrement addressing (either preincrement or
+postincrement) is allowed.
+
+@cindex @samp{r} in constraint
+@cindex registers in constraints
+@item @samp{r}
+A register operand is allowed provided that it is in a general
+register.
+
+@cindex constants in constraints
+@cindex @samp{i} in constraint
+@item @samp{i}
+An immediate integer operand (one with constant value) is allowed.
+This includes symbolic constants whose values will be known only at
+assembly time.
+
+@cindex @samp{n} in constraint
+@item @samp{n}
+An immediate integer operand with a known numeric value is allowed.
+Many systems cannot support assembly-time constants for operands less
+than a word wide.  Constraints for these operands should use @samp{n}
+rather than @samp{i}.
+
+@cindex @samp{I} in constraint
+@item @samp{I}, @samp{J}, @samp{K}, @dots{} @samp{P}
+Other letters in the range @samp{I} through @samp{P} may be defined in
+a machine-dependent fashion to permit immediate integer operands with
+explicit integer values in specified ranges.  For example, on the
+68000, @samp{I} is defined to stand for the range of values 1 to 8.
+This is the range permitted as a shift count in the shift
+instructions.
+
+@cindex @samp{E} in constraint
+@item @samp{E}
+An immediate floating operand (expression code @code{const_double}) is
+allowed, but only if the target floating point format is the same as
+that of the host machine (on which the compiler is running).
+
+@cindex @samp{F} in constraint
+@item @samp{F}
+An immediate floating operand (expression code @code{const_double}) is
+allowed.
+
+@cindex @samp{G} in constraint
+@cindex @samp{H} in constraint
+@item @samp{G}, @samp{H}
+@samp{G} and @samp{H} may be defined in a machine-dependent fashion to
+permit immediate floating operands in particular ranges of values.
+
+@cindex @samp{s} in constraint
+@item @samp{s}
+An immediate integer operand whose value is not an explicit integer is
+allowed.
+
+This might appear strange; if an insn allows a constant operand with a
+value not known at compile time, it certainly must allow any known
+value.  So why use @samp{s} instead of @samp{i}?  Sometimes it allows
+better code to be generated.
+
+For example, on the 68000 in a fullword instruction it is possible to
+use an immediate operand; but if the immediate value is between @minus{}128
+and 127, better code results from loading the value into a register and
+using the register.  This is because the load into the register can be
+done with a @samp{moveq} instruction.  We arrange for this to happen
+by defining the letter @samp{K} to mean ``any integer outside the
+range @minus{}128 to 127'', and then specifying @samp{Ks} in the operand
+constraints.
+
+@cindex @samp{g} in constraint
+@item @samp{g}
+Any register, memory or immediate integer operand is allowed, except for
+registers that are not general registers.
+
+@cindex @samp{X} in constraint
+@item @samp{X}
+@ifset INTERNALS
+Any operand whatsoever is allowed, even if it does not satisfy
+@code{general_operand}.  This is normally used in the constraint of
+a @code{match_scratch} when certain alternatives will not actually
+require a scratch register.
+@end ifset
+@ifclear INTERNALS
+Any operand whatsoever is allowed.
+@end ifclear
+
+@cindex @samp{0} in constraint
+@cindex digits in constraint
+@item @samp{0}, @samp{1}, @samp{2}, @dots{} @samp{9}
+An operand that matches the specified operand number is allowed.  If a
+digit is used together with letters within the same alternative, the
+digit should come last.
+
+This number is allowed to be more than a single digit.  If multiple
+digits are encountered consecutavely, they are interpreted as a single
+decimal integer.  There is scant chance for ambiguity, since to-date
+it has never been desirable that @samp{10} be interpreted as matching
+either operand 1 @emph{or} operand 0.  Should this be desired, one
+can use multiple alternatives instead.
+
+@cindex matching constraint
+@cindex constraint, matching
+This is called a @dfn{matching constraint} and what it really means is
+that the assembler has only a single operand that fills two roles
+@ifset INTERNALS
+considered separate in the RTL insn.  For example, an add insn has two
+input operands and one output operand in the RTL, but on most CISC
+@end ifset
+@ifclear INTERNALS
+which @code{asm} distinguishes.  For example, an add instruction uses
+two input operands and an output operand, but on most CISC
+@end ifclear
+machines an add instruction really has only two operands, one of them an
+input-output operand:
+
+@smallexample
+addl #35,r12
+@end smallexample
+
+Matching constraints are used in these circumstances.
+More precisely, the two operands that match must include one input-only
+operand and one output-only operand.  Moreover, the digit must be a
+smaller number than the number of the operand that uses it in the
+constraint.
+
+@ifset INTERNALS
+For operands to match in a particular case usually means that they
+are identical-looking RTL expressions.  But in a few special cases
+specific kinds of dissimilarity are allowed.  For example, @code{*x}
+as an input operand will match @code{*x++} as an output operand.
+For proper results in such cases, the output template should always
+use the output-operand's number when printing the operand.
+@end ifset
+
+@cindex load address instruction
+@cindex push address instruction
+@cindex address constraints
+@cindex @samp{p} in constraint
+@item @samp{p}
+An operand that is a valid memory address is allowed.  This is
+for ``load address'' and ``push address'' instructions.
+
+@findex address_operand
+@samp{p} in the constraint must be accompanied by @code{address_operand}
+as the predicate in the @code{match_operand}.  This predicate interprets
+the mode specified in the @code{match_operand} as the mode of the memory
+reference for which the address would be valid.
+
+@cindex other register constraints
+@cindex extensible constraints
+@item @var{other-letters}
+Other letters can be defined in machine-dependent fashion to stand for
+particular classes of registers or other arbitrary operand types.
+@samp{d}, @samp{a} and @samp{f} are defined on the 68000/68020 to stand
+for data, address and floating point registers.
+
+@ifset INTERNALS
+The machine description macro @code{REG_CLASS_FROM_LETTER} has first
+cut at the otherwise unused letters.  If it evaluates to @code{NO_REGS},
+then @code{EXTRA_CONSTRAINT} is evaluated.
+
+A typical use for @code{EXTRA_CONSTRANT} would be to distinguish certain
+types of memory references that affect other insn operands.
+@end ifset
+@end table
+
+@ifset INTERNALS
+In order to have valid assembler code, each operand must satisfy
+its constraint.  But a failure to do so does not prevent the pattern
+from applying to an insn.  Instead, it directs the compiler to modify
+the code so that the constraint will be satisfied.  Usually this is
+done by copying an operand into a register.
+
+Contrast, therefore, the two instruction patterns that follow:
+
+@smallexample
+(define_insn ""
+  [(set (match_operand:SI 0 "general_operand" "=r")
+        (plus:SI (match_dup 0)
+                 (match_operand:SI 1 "general_operand" "r")))]
+  ""
+  "@dots{}")
+@end smallexample
+
+@noindent
+which has two operands, one of which must appear in two places, and
+
+@smallexample
+(define_insn ""
+  [(set (match_operand:SI 0 "general_operand" "=r")
+        (plus:SI (match_operand:SI 1 "general_operand" "0")
+                 (match_operand:SI 2 "general_operand" "r")))]
+  ""
+  "@dots{}")
+@end smallexample
+
+@noindent
+which has three operands, two of which are required by a constraint to be
+identical.  If we are considering an insn of the form
+
+@smallexample
+(insn @var{n} @var{prev} @var{next}
+  (set (reg:SI 3)
+       (plus:SI (reg:SI 6) (reg:SI 109)))
+  @dots{})
+@end smallexample
+
+@noindent
+the first pattern would not apply at all, because this insn does not
+contain two identical subexpressions in the right place.  The pattern would
+say, ``That does not look like an add instruction; try other patterns.''
+The second pattern would say, ``Yes, that's an add instruction, but there
+is something wrong with it.''  It would direct the reload pass of the
+compiler to generate additional insns to make the constraint true.  The
+results might look like this:
+
+@smallexample
+(insn @var{n2} @var{prev} @var{n}
+  (set (reg:SI 3) (reg:SI 6))
+  @dots{})
+
+(insn @var{n} @var{n2} @var{next}
+  (set (reg:SI 3)
+       (plus:SI (reg:SI 3) (reg:SI 109)))
+  @dots{})
+@end smallexample
+
+It is up to you to make sure that each operand, in each pattern, has
+constraints that can handle any RTL expression that could be present for
+that operand.  (When multiple alternatives are in use, each pattern must,
+for each possible combination of operand expressions, have at least one
+alternative which can handle that combination of operands.)  The
+constraints don't need to @emph{allow} any possible operand---when this is
+the case, they do not constrain---but they must at least point the way to
+reloading any possible operand so that it will fit.
+
+@itemize @bullet
+@item
+If the constraint accepts whatever operands the predicate permits,
+there is no problem: reloading is never necessary for this operand.
+
+For example, an operand whose constraints permit everything except
+registers is safe provided its predicate rejects registers.
+
+An operand whose predicate accepts only constant values is safe
+provided its constraints include the letter @samp{i}.  If any possible
+constant value is accepted, then nothing less than @samp{i} will do;
+if the predicate is more selective, then the constraints may also be
+more selective.
+
+@item
+Any operand expression can be reloaded by copying it into a register.
+So if an operand's constraints allow some kind of register, it is
+certain to be safe.  It need not permit all classes of registers; the
+compiler knows how to copy a register into another register of the
+proper class in order to make an instruction valid.
+
+@cindex nonoffsettable memory reference
+@cindex memory reference, nonoffsettable
+@item
+A nonoffsettable memory reference can be reloaded by copying the
+address into a register.  So if the constraint uses the letter
+@samp{o}, all memory references are taken care of.
+
+@item
+A constant operand can be reloaded by allocating space in memory to
+hold it as preinitialized data.  Then the memory reference can be used
+in place of the constant.  So if the constraint uses the letters
+@samp{o} or @samp{m}, constant operands are not a problem.
+
+@item
+If the constraint permits a constant and a pseudo register used in an insn
+was not allocated to a hard register and is equivalent to a constant,
+the register will be replaced with the constant.  If the predicate does
+not permit a constant and the insn is re-recognized for some reason, the
+compiler will crash.  Thus the predicate must always recognize any
+objects allowed by the constraint.
+@end itemize
+
+If the operand's predicate can recognize registers, but the constraint does
+not permit them, it can make the compiler crash.  When this operand happens
+to be a register, the reload pass will be stymied, because it does not know
+how to copy a register temporarily into memory.
+
+If the predicate accepts a unary operator, the constraint applies to the
+operand.  For example, the MIPS processor at ISA level 3 supports an
+instruction which adds two registers in @code{SImode} to produce a
+@code{DImode} result, but only if the registers are correctly sign
+extended.  This predicate for the input operands accepts a
+@code{sign_extend} of an @code{SImode} register.  Write the constraint
+to indicate the type of register that is required for the operand of the
+@code{sign_extend}.
+@end ifset
+
+@node Multi-Alternative
+@subsection Multiple Alternative Constraints
+@cindex multiple alternative constraints
+
+Sometimes a single instruction has multiple alternative sets of possible
+operands.  For example, on the 68000, a logical-or instruction can combine
+register or an immediate value into memory, or it can combine any kind of
+operand into a register; but it cannot combine one memory location into
+another.
+
+These constraints are represented as multiple alternatives.  An alternative
+can be described by a series of letters for each operand.  The overall
+constraint for an operand is made from the letters for this operand
+from the first alternative, a comma, the letters for this operand from
+the second alternative, a comma, and so on until the last alternative.
+@ifset INTERNALS
+Here is how it is done for fullword logical-or on the 68000:
+
+@smallexample
+(define_insn "iorsi3"
+  [(set (match_operand:SI 0 "general_operand" "=m,d")
+        (ior:SI (match_operand:SI 1 "general_operand" "%0,0")
+                (match_operand:SI 2 "general_operand" "dKs,dmKs")))]
+  @dots{})
+@end smallexample
+
+The first alternative has @samp{m} (memory) for operand 0, @samp{0} for
+operand 1 (meaning it must match operand 0), and @samp{dKs} for operand
+2.  The second alternative has @samp{d} (data register) for operand 0,
+@samp{0} for operand 1, and @samp{dmKs} for operand 2.  The @samp{=} and
+@samp{%} in the constraints apply to all the alternatives; their
+meaning is explained in the next section (@pxref{Class Preferences}).
+@end ifset
+
+@c FIXME Is this ? and ! stuff of use in asm()?  If not, hide unless INTERNAL
+If all the operands fit any one alternative, the instruction is valid.
+Otherwise, for each alternative, the compiler counts how many instructions
+must be added to copy the operands so that that alternative applies.
+The alternative requiring the least copying is chosen.  If two alternatives
+need the same amount of copying, the one that comes first is chosen.
+These choices can be altered with the @samp{?} and @samp{!} characters:
+
+@table @code
+@cindex @samp{?} in constraint
+@cindex question mark
+@item ?
+Disparage slightly the alternative that the @samp{?} appears in,
+as a choice when no alternative applies exactly.  The compiler regards
+this alternative as one unit more costly for each @samp{?} that appears
+in it.
+
+@cindex @samp{!} in constraint
+@cindex exclamation point
+@item !
+Disparage severely the alternative that the @samp{!} appears in.
+This alternative can still be used if it fits without reloading,
+but if reloading is needed, some other alternative will be used.
+@end table
+
+@ifset INTERNALS
+When an insn pattern has multiple alternatives in its constraints, often
+the appearance of the assembler code is determined mostly by which
+alternative was matched.  When this is so, the C code for writing the
+assembler code can use the variable @code{which_alternative}, which is
+the ordinal number of the alternative that was actually satisfied (0 for
+the first, 1 for the second alternative, etc.).  @xref{Output Statement}.
+@end ifset
+
+@ifset INTERNALS
+@node Class Preferences
+@subsection Register Class Preferences
+@cindex class preference constraints
+@cindex register class preference constraints
+
+@cindex voting between constraint alternatives
+The operand constraints have another function: they enable the compiler
+to decide which kind of hardware register a pseudo register is best
+allocated to.  The compiler examines the constraints that apply to the
+insns that use the pseudo register, looking for the machine-dependent
+letters such as @samp{d} and @samp{a} that specify classes of registers.
+The pseudo register is put in whichever class gets the most ``votes''.
+The constraint letters @samp{g} and @samp{r} also vote: they vote in
+favor of a general register.  The machine description says which registers
+are considered general.
+
+Of course, on some machines all registers are equivalent, and no register
+classes are defined.  Then none of this complexity is relevant.
+@end ifset
+
+@node Modifiers
+@subsection Constraint Modifier Characters
+@cindex modifiers in constraints
+@cindex constraint modifier characters
+
+@c prevent bad page break with this line
+Here are constraint modifier characters.
+
+@table @samp
+@cindex @samp{=} in constraint
+@item =
+Means that this operand is write-only for this instruction: the previous
+value is discarded and replaced by output data.
+
+@cindex @samp{+} in constraint
+@item +
+Means that this operand is both read and written by the instruction.
+
+When the compiler fixes up the operands to satisfy the constraints,
+it needs to know which operands are inputs to the instruction and
+which are outputs from it.  @samp{=} identifies an output; @samp{+}
+identifies an operand that is both input and output; all other operands
+are assumed to be input only.
+
+If you specify @samp{=} or @samp{+} in a constraint, you put it in the
+first character of the constraint string.
+
+@cindex @samp{&} in constraint
+@cindex earlyclobber operand
+@item &
+Means (in a particular alternative) that this operand is an
+@dfn{earlyclobber} operand, which is modified before the instruction is
+finished using the input operands.  Therefore, this operand may not lie
+in a register that is used as an input operand or as part of any memory
+address.
+
+@samp{&} applies only to the alternative in which it is written.  In
+constraints with multiple alternatives, sometimes one alternative
+requires @samp{&} while others do not.  See, for example, the
+@samp{movdf} insn of the 68000.
+
+An input operand can be tied to an earlyclobber operand if its only
+use as an input occurs before the early result is written.  Adding
+alternatives of this form often allows GCC to produce better code
+when only some of the inputs can be affected by the earlyclobber.
+See, for example, the @samp{mulsi3} insn of the ARM@.
+
+@samp{&} does not obviate the need to write @samp{=}.
+
+@cindex @samp{%} in constraint
+@item %
+Declares the instruction to be commutative for this operand and the
+following operand.  This means that the compiler may interchange the
+two operands if that is the cheapest way to make all operands fit the
+constraints.
+@ifset INTERNALS
+This is often used in patterns for addition instructions
+that really have only two operands: the result must go in one of the
+arguments.  Here for example, is how the 68000 halfword-add
+instruction is defined:
+
+@smallexample
+(define_insn "addhi3"
+  [(set (match_operand:HI 0 "general_operand" "=m,r")
+     (plus:HI (match_operand:HI 1 "general_operand" "%0,0")
+              (match_operand:HI 2 "general_operand" "di,g")))]
+  @dots{})
+@end smallexample
+@end ifset
+
+@cindex @samp{#} in constraint
+@item #
+Says that all following characters, up to the next comma, are to be
+ignored as a constraint.  They are significant only for choosing
+register preferences.
+
+@cindex @samp{*} in constraint
+@item *
+Says that the following character should be ignored when choosing
+register preferences.  @samp{*} has no effect on the meaning of the
+constraint as a constraint, and no effect on reloading.
+
+@ifset INTERNALS
+Here is an example: the 68000 has an instruction to sign-extend a
+halfword in a data register, and can also sign-extend a value by
+copying it into an address register.  While either kind of register is
+acceptable, the constraints on an address-register destination are
+less strict, so it is best if register allocation makes an address
+register its goal.  Therefore, @samp{*} is used so that the @samp{d}
+constraint letter (for data register) is ignored when computing
+register preferences.
+
+@smallexample
+(define_insn "extendhisi2"
+  [(set (match_operand:SI 0 "general_operand" "=*d,a")
+        (sign_extend:SI
+         (match_operand:HI 1 "general_operand" "0,g")))]
+  @dots{})
+@end smallexample
+@end ifset
+@end table
+
+@node Machine Constraints
+@subsection Constraints for Particular Machines
+@cindex machine specific constraints
+@cindex constraints, machine specific
+
+Whenever possible, you should use the general-purpose constraint letters
+in @code{asm} arguments, since they will convey meaning more readily to
+people reading your code.  Failing that, use the constraint letters
+that usually have very similar meanings across architectures.  The most
+commonly used constraints are @samp{m} and @samp{r} (for memory and
+general-purpose registers respectively; @pxref{Simple Constraints}), and
+@samp{I}, usually the letter indicating the most common
+immediate-constant format.
+
+For each machine architecture, the
+@file{config/@var{machine}/@var{machine}.h} file defines additional
+constraints.  These constraints are used by the compiler itself for
+instruction generation, as well as for @code{asm} statements; therefore,
+some of the constraints are not particularly interesting for @code{asm}.
+The constraints are defined through these macros:
+
+@table @code
+@item REG_CLASS_FROM_LETTER
+Register class constraints (usually lower case).
+
+@item CONST_OK_FOR_LETTER_P
+Immediate constant constraints, for non-floating point constants of
+word size or smaller precision (usually upper case).
+
+@item CONST_DOUBLE_OK_FOR_LETTER_P
+Immediate constant constraints, for all floating point constants and for
+constants of greater than word size precision (usually upper case).
+
+@item EXTRA_CONSTRAINT
+Special cases of registers or memory.  This macro is not required, and
+is only defined for some machines.
+@end table
+
+Inspecting these macro definitions in the compiler source for your
+machine is the best way to be certain you have the right constraints.
+However, here is a summary of the machine-dependent constraints
+available on some particular machines.
+
+@table @emph
+@item ARM family---@file{arm.h}
+@table @code
+@item f
+Floating-point register
+
+@item F
+One of the floating-point constants 0.0, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0
+or 10.0
+
+@item G
+Floating-point constant that would satisfy the constraint @samp{F} if it
+were negated
+
+@item I
+Integer that is valid as an immediate operand in a data processing
+instruction.  That is, an integer in the range 0 to 255 rotated by a
+multiple of 2
+
+@item J
+Integer in the range @minus{}4095 to 4095
+
+@item K
+Integer that satisfies constraint @samp{I} when inverted (ones complement)
+
+@item L
+Integer that satisfies constraint @samp{I} when negated (twos complement)
+
+@item M
+Integer in the range 0 to 32
+
+@item Q
+A memory reference where the exact address is in a single register
+(`@samp{m}' is preferable for @code{asm} statements)
+
+@item R
+An item in the constant pool
+
+@item S
+A symbol in the text segment of the current file
+@end table
+
+@item AMD 29000 family---@file{a29k.h}
+@table @code
+@item l
+Local register 0
+
+@item b
+Byte Pointer (@samp{BP}) register
+
+@item q
+@samp{Q} register
+
+@item h
+Special purpose register
+
+@item A
+First accumulator register
+
+@item a
+Other accumulator register
+
+@item f
+Floating point register
+
+@item I
+Constant greater than 0, less than 0x100
+
+@item J
+Constant greater than 0, less than 0x10000
+
+@item K
+Constant whose high 24 bits are on (1)
+
+@item L
+16-bit constant whose high 8 bits are on (1)
+
+@item M
+32-bit constant whose high 16 bits are on (1)
+
+@item N
+32-bit negative constant that fits in 8 bits
+
+@item O
+The constant 0x80000000 or, on the 29050, any 32-bit constant
+whose low 16 bits are 0.
+
+@item P
+16-bit negative constant that fits in 8 bits
+
+@item G
+@itemx H
+A floating point constant (in @code{asm} statements, use the machine
+independent @samp{E} or @samp{F} instead)
+@end table
+
+@item AVR family---@file{avr.h}
+@table @code
+@item l
+Registers from r0 to r15
+
+@item a
+Registers from r16 to r23
+
+@item d
+Registers from r16 to r31
+
+@item w
+Registers from r24 to r31.  These registers can be used in @samp{adiw} command
+
+@item e
+Pointer register (r26--r31)
+
+@item b
+Base pointer register (r28--r31)
+
+@item q
+Stack pointer register (SPH:SPL)
+
+@item t
+Temporary register r0
+
+@item x
+Register pair X (r27:r26)
+
+@item y
+Register pair Y (r29:r28)
+
+@item z
+Register pair Z (r31:r30)
+
+@item I
+Constant greater than @minus{}1, less than 64
+
+@item J
+Constant greater than @minus{}64, less than 1
+
+@item K
+Constant integer 2
+
+@item L
+Constant integer 0
+
+@item M
+Constant that fits in 8 bits
+
+@item N
+Constant integer @minus{}1
+
+@item O
+Constant integer 8, 16, or 24
+
+@item P
+Constant integer 1
+
+@item G
+A floating point constant 0.0
+@end table
+
+@item IBM RS6000---@file{rs6000.h}
+@table @code
+@item b
+Address base register
+
+@item f
+Floating point register
+
+@item h
+@samp{MQ}, @samp{CTR}, or @samp{LINK} register
+
+@item q
+@samp{MQ} register
+
+@item c
+@samp{CTR} register
+
+@item l
+@samp{LINK} register
+
+@item x
+@samp{CR} register (condition register) number 0
+
+@item y
+@samp{CR} register (condition register)
+
+@item z
+@samp{FPMEM} stack memory for FPR-GPR transfers
+
+@item I
+Signed 16-bit constant
+
+@item J
+Unsigned 16-bit constant shifted left 16 bits (use @samp{L} instead for
+@code{SImode} constants)
+
+@item K
+Unsigned 16-bit constant
+
+@item L
+Signed 16-bit constant shifted left 16 bits
+
+@item M
+Constant larger than 31
+
+@item N
+Exact power of 2
+
+@item O
+Zero
+
+@item P
+Constant whose negation is a signed 16-bit constant
+
+@item G
+Floating point constant that can be loaded into a register with one
+instruction per word
+
+@item Q
+Memory operand that is an offset from a register (@samp{m} is preferable
+for @code{asm} statements)
+
+@item R
+AIX TOC entry
+
+@item S
+Constant suitable as a 64-bit mask operand
+
+@item T
+Constant suitable as a 32-bit mask operand
+
+@item U
+System V Release 4 small data area reference
+@end table
+
+@item Intel 386---@file{i386.h}
+@table @code
+@item q
+@samp{a}, @code{b}, @code{c}, or @code{d} register for the i386.
+For x86-64 it is equivalent to @samp{r} class. (for 8-bit instructions that
+do not use upper halves)
+
+@item Q
+@samp{a}, @code{b}, @code{c}, or @code{d} register. (for 8-bit instructions,
+that do use upper halves)
+
+@item R
+Legacy register---equivalent to @code{r} class in i386 mode.
+(for non-8-bit registers used together with 8-bit upper halves in a single
+instruction)
+
+@item A
+Specifies the @samp{a} or @samp{d} registers.  This is primarily useful
+for 64-bit integer values (when in 32-bit mode) intended to be returned
+with the @samp{d} register holding the most significant bits and the
+@samp{a} register holding the least significant bits.
+
+@item f
+Floating point register
+
+@item t
+First (top of stack) floating point register
+
+@item u
+Second floating point register
+
+@item a
+@samp{a} register
+
+@item b
+@samp{b} register
+
+@item c
+@samp{c} register
+
+@item d
+@samp{d} register
+
+@item D
+@samp{di} register
+
+@item S
+@samp{si} register
+
+@item x
+@samp{xmm} SSE register
+
+@item y
+MMX register
+
+@item I
+Constant in range 0 to 31 (for 32-bit shifts)
+
+@item J
+Constant in range 0 to 63 (for 64-bit shifts)
+
+@item K
+@samp{0xff}
+
+@item L
+@samp{0xffff}
+
+@item M
+0, 1, 2, or 3 (shifts for @code{lea} instruction)
+
+@item N
+Constant in range 0 to 255 (for @code{out} instruction)
+
+@item Z
+Constant in range 0 to @code{0xffffffff} or symbolic reference known to fit specified range.
+(for using immediates in zero extending 32-bit to 64-bit x86-64 instructions)
+
+@item e
+Constant in range @minus{}2147483648 to 2147483647 or symbolic reference known to fit specified range.
+(for using immediates in 64-bit x86-64 instructions)
+
+@item G
+Standard 80387 floating point constant
+@end table
+
+@item Intel 960---@file{i960.h}
+@table @code
+@item f
+Floating point register (@code{fp0} to @code{fp3})
+
+@item l
+Local register (@code{r0} to @code{r15})
+
+@item b
+Global register (@code{g0} to @code{g15})
+
+@item d
+Any local or global register
+
+@item I
+Integers from 0 to 31
+
+@item J
+0
+
+@item K
+Integers from @minus{}31 to 0
+
+@item G
+Floating point 0
+
+@item H
+Floating point 1
+@end table
+
+@item MIPS---@file{mips.h}
+@table @code
+@item d
+General-purpose integer register
+
+@item f
+Floating-point register (if available)
+
+@item h
+@samp{Hi} register
+
+@item l
+@samp{Lo} register
+
+@item x
+@samp{Hi} or @samp{Lo} register
+
+@item y
+General-purpose integer register
+
+@item z
+Floating-point status register
+
+@item I
+Signed 16-bit constant (for arithmetic instructions)
+
+@item J
+Zero
+
+@item K
+Zero-extended 16-bit constant (for logic instructions)
+
+@item L
+Constant with low 16 bits zero (can be loaded with @code{lui})
+
+@item M
+32-bit constant which requires two instructions to load (a constant
+which is not @samp{I}, @samp{K}, or @samp{L})
+
+@item N
+Negative 16-bit constant
+
+@item O
+Exact power of two
+
+@item P
+Positive 16-bit constant
+
+@item G
+Floating point zero
+
+@item Q
+Memory reference that can be loaded with more than one instruction
+(@samp{m} is preferable for @code{asm} statements)
+
+@item R
+Memory reference that can be loaded with one instruction
+(@samp{m} is preferable for @code{asm} statements)
+
+@item S
+Memory reference in external OSF/rose PIC format
+(@samp{m} is preferable for @code{asm} statements)
+@end table
+
+@item Motorola 680x0---@file{m68k.h}
+@table @code
+@item a
+Address register
+
+@item d
+Data register
+
+@item f
+68881 floating-point register, if available
+
+@item x
+Sun FPA (floating-point) register, if available
+
+@item y
+First 16 Sun FPA registers, if available
+
+@item I
+Integer in the range 1 to 8
+
+@item J
+16-bit signed number
+
+@item K
+Signed number whose magnitude is greater than 0x80
+
+@item L
+Integer in the range @minus{}8 to @minus{}1
+
+@item M
+Signed number whose magnitude is greater than 0x100
+
+@item G
+Floating point constant that is not a 68881 constant
+
+@item H
+Floating point constant that can be used by Sun FPA
+@end table
+
+@item Motorola 68HC11 & 68HC12 families---@file{m68hc11.h}
+@table @code
+@item a
+Register 'a'
+
+@item b
+Register 'b'
+
+@item d
+Register 'd'
+
+@item q
+An 8-bit register
+
+@item t
+Temporary soft register _.tmp
+
+@item u
+A soft register _.d1 to _.d31
+
+@item w
+Stack pointer register
+
+@item x
+Register 'x'
+
+@item y
+Register 'y'
+
+@item z
+Pseudo register 'z' (replaced by 'x' or 'y' at the end)
+
+@item A
+An address register: x, y or z
+
+@item B
+An address register: x or y
+
+@item D
+Register pair (x:d) to form a 32-bit value
+
+@item L
+Constants in the range @minus{}65536 to 65535
+
+@item M
+Constants whose 16-bit low part is zero
+
+@item N
+Constant integer 1 or @minus{}1
+
+@item O
+Constant integer 16
+
+@item P
+Constants in the range @minus{}8 to 2
+
+@end table
+
+@need 1000
+@item SPARC---@file{sparc.h}
+@table @code
+@item f
+Floating-point register that can hold 32- or 64-bit values.
+
+@item e
+Floating-point register that can hold 64- or 128-bit values.
+
+@item I
+Signed 13-bit constant
+
+@item J
+Zero
+
+@item K
+32-bit constant with the low 12 bits clear (a constant that can be
+loaded with the @code{sethi} instruction)
+
+@item G
+Floating-point zero
+
+@item H
+Signed 13-bit constant, sign-extended to 32 or 64 bits
+
+@item Q
+Floating-point constant whose integral representation can
+be moved into an integer register using a single sethi
+instruction
+
+@item R
+Floating-point constant whose integral representation can
+be moved into an integer register using a single mov
+instruction
+
+@item S
+Floating-point constant whose integral representation can
+be moved into an integer register using a high/lo_sum
+instruction sequence
+
+@item T
+Memory address aligned to an 8-byte boundary
+
+@item U
+Even register
+
+@end table
+
+@item TMS320C3x/C4x---@file{c4x.h}
+@table @code
+@item a
+Auxiliary (address) register (ar0-ar7)
+
+@item b
+Stack pointer register (sp)
+
+@item c
+Standard (32-bit) precision integer register
+
+@item f
+Extended (40-bit) precision register (r0-r11)
+
+@item k
+Block count register (bk)
+
+@item q
+Extended (40-bit) precision low register (r0-r7)
+
+@item t
+Extended (40-bit) precision register (r0-r1)
+
+@item u
+Extended (40-bit) precision register (r2-r3)
+
+@item v
+Repeat count register (rc)
+
+@item x
+Index register (ir0-ir1)
+
+@item y
+Status (condition code) register (st)
+
+@item z
+Data page register (dp)
+
+@item G
+Floating-point zero
+
+@item H
+Immediate 16-bit floating-point constant
+
+@item I
+Signed 16-bit constant
+
+@item J
+Signed 8-bit constant
+
+@item K
+Signed 5-bit constant
+
+@item L
+Unsigned 16-bit constant
+
+@item M
+Unsigned 8-bit constant
+
+@item N
+Ones complement of unsigned 16-bit constant
+
+@item O
+High 16-bit constant (32-bit constant with 16 LSBs zero)
+
+@item Q
+Indirect memory reference with signed 8-bit or index register displacement
+
+@item R
+Indirect memory reference with unsigned 5-bit displacement
+
+@item S
+Indirect memory reference with 1 bit or index register displacement
+
+@item T
+Direct memory reference
+
+@item U
+Symbolic address
+
+@end table
+
+@item S/390 and zSeries---@file{s390.h}
+@table @code
+@item a
+Address register (general purpose register except r0)
+
+@item d
+Data register (arbitrary general purpose register)
+
+@item f
+Floating-point register
+
+@item I
+Unsigned 8-bit constant (0--255)
+
+@item J
+Unsigned 12-bit constant (0--4095)
+
+@item K
+Signed 16-bit constant (@minus{}32768--32767)
+
+@item L
+Unsigned 16-bit constant (0--65535)
+
+@item Q
+Memory reference without index register
+
+@item S
+Symbolic constant suitable for use with the @code{larl} instruction
+
+@end table
+
+@item Xstormy16---@file{stormy16.h}
+@table @code
+@item a
+Register r0.
+
+@item b
+Register r1.
+
+@item c
+Register r2.
+
+@item d
+Register r8.
+
+@item e
+Registers r0 through r7.
+
+@item t
+Registers r0 and r1.
+
+@item y
+The carry register.
+
+@item z
+Registers r8 and r9.
+
+@item I
+A constant between 0 and 3 inclusive.
+
+@item J
+A constant that has exactly one bit set.
+
+@item K
+A constant that has exactly one bit clear.
+
+@item L
+A constant between 0 and 255 inclusive.
+
+@item M
+A constant between @minus{}255 and 0 inclusive.
+
+@item N
+A constant between @minus{}3 and 0 inclusive.
+
+@item O
+A constant between 1 and 4 inclusive.
+
+@item P
+A constant between @minus{}4 and @minus{}1 inclusive.
+
+@item Q
+A memory reference that is a stack push.
+
+@item R
+A memory reference that is a stack pop.
+
+@item S
+A memory reference that refers to an constant address of known value.
+
+@item T
+The register indicated by Rx (not implemented yet).
+
+@item U
+A constant that is not between 2 and 15 inclusive.
+
+@end table
+
+@item Xtensa---@file{xtensa.h}
+@table @code
+@item a
+General-purpose 32-bit register
+
+@item b
+One-bit boolean register
+
+@item A
+MAC16 40-bit accumulator register
+
+@item I
+Signed 12-bit integer constant, for use in MOVI instructions
+
+@item J
+Signed 8-bit integer constant, for use in ADDI instructions
+
+@item K
+Integer constant valid for BccI instructions
+
+@item L
+Unsigned constant valid for BccUI instructions
+
+@end table
+
+@end table
+
+@ifset INTERNALS
+@node Standard Names
+@section Standard Pattern Names For Generation
+@cindex standard pattern names
+@cindex pattern names
+@cindex names, pattern
+
+Here is a table of the instruction names that are meaningful in the RTL
+generation pass of the compiler.  Giving one of these names to an
+instruction pattern tells the RTL generation pass that it can use the
+pattern to accomplish a certain task.
+
+@table @asis
+@cindex @code{mov@var{m}} instruction pattern
+@item @samp{mov@var{m}}
+Here @var{m} stands for a two-letter machine mode name, in lower case.
+This instruction pattern moves data with that machine mode from operand
+1 to operand 0.  For example, @samp{movsi} moves full-word data.
+
+If operand 0 is a @code{subreg} with mode @var{m} of a register whose
+own mode is wider than @var{m}, the effect of this instruction is
+to store the specified value in the part of the register that corresponds
+to mode @var{m}.  Bits outside of @var{m}, but which are within the
+same target word as the @code{subreg} are undefined.  Bits which are
+outside the target word are left unchanged.
+
+This class of patterns is special in several ways.  First of all, each
+of these names up to and including full word size @emph{must} be defined,
+because there is no other way to copy a datum from one place to another.
+If there are patterns accepting operands in larger modes,
+@samp{mov@var{m}} must be defined for integer modes of those sizes.
+
+Second, these patterns are not used solely in the RTL generation pass.
+Even the reload pass can generate move insns to copy values from stack
+slots into temporary registers.  When it does so, one of the operands is
+a hard register and the other is an operand that can need to be reloaded
+into a register.
+
+@findex force_reg
+Therefore, when given such a pair of operands, the pattern must generate
+RTL which needs no reloading and needs no temporary registers---no
+registers other than the operands.  For example, if you support the
+pattern with a @code{define_expand}, then in such a case the
+@code{define_expand} mustn't call @code{force_reg} or any other such
+function which might generate new pseudo registers.
+
+This requirement exists even for subword modes on a RISC machine where
+fetching those modes from memory normally requires several insns and
+some temporary registers.
+
+@findex change_address
+During reload a memory reference with an invalid address may be passed
+as an operand.  Such an address will be replaced with a valid address
+later in the reload pass.  In this case, nothing may be done with the
+address except to use it as it stands.  If it is copied, it will not be
+replaced with a valid address.  No attempt should be made to make such
+an address into a valid address and no routine (such as
+@code{change_address}) that will do so may be called.  Note that
+@code{general_operand} will fail when applied to such an address.
+
+@findex reload_in_progress
+The global variable @code{reload_in_progress} (which must be explicitly
+declared if required) can be used to determine whether such special
+handling is required.
+
+The variety of operands that have reloads depends on the rest of the
+machine description, but typically on a RISC machine these can only be
+pseudo registers that did not get hard registers, while on other
+machines explicit memory references will get optional reloads.
+
+If a scratch register is required to move an object to or from memory,
+it can be allocated using @code{gen_reg_rtx} prior to life analysis.
+
+If there are cases which need scratch registers during or after reload,
+you must define @code{SECONDARY_INPUT_RELOAD_CLASS} and/or
+@code{SECONDARY_OUTPUT_RELOAD_CLASS} to detect them, and provide
+patterns @samp{reload_in@var{m}} or @samp{reload_out@var{m}} to handle
+them.  @xref{Register Classes}.
+
+@findex no_new_pseudos
+The global variable @code{no_new_pseudos} can be used to determine if it
+is unsafe to create new pseudo registers.  If this variable is nonzero, then
+it is unsafe to call @code{gen_reg_rtx} to allocate a new pseudo.
+
+The constraints on a @samp{mov@var{m}} must permit moving any hard
+register to any other hard register provided that
+@code{HARD_REGNO_MODE_OK} permits mode @var{m} in both registers and
+@code{REGISTER_MOVE_COST} applied to their classes returns a value of 2.
+
+It is obligatory to support floating point @samp{mov@var{m}}
+instructions into and out of any registers that can hold fixed point
+values, because unions and structures (which have modes @code{SImode} or
+@code{DImode}) can be in those registers and they may have floating
+point members.
+
+There may also be a need to support fixed point @samp{mov@var{m}}
+instructions in and out of floating point registers.  Unfortunately, I
+have forgotten why this was so, and I don't know whether it is still
+true.  If @code{HARD_REGNO_MODE_OK} rejects fixed point values in
+floating point registers, then the constraints of the fixed point
+@samp{mov@var{m}} instructions must be designed to avoid ever trying to
+reload into a floating point register.
+
+@cindex @code{reload_in} instruction pattern
+@cindex @code{reload_out} instruction pattern
+@item @samp{reload_in@var{m}}
+@itemx @samp{reload_out@var{m}}
+Like @samp{mov@var{m}}, but used when a scratch register is required to
+move between operand 0 and operand 1.  Operand 2 describes the scratch
+register.  See the discussion of the @code{SECONDARY_RELOAD_CLASS}
+macro in @pxref{Register Classes}.
+
+There are special restrictions on the form of the @code{match_operand}s
+used in these patterns.  First, only the predicate for the reload 
+operand is examined, i.e., @code{reload_in} examines operand 1, but not
+the predicates for operand 0 or 2.  Second, there may be only one
+alternative in the constraints.  Third, only a single register class
+letter may be used for the constraint; subsequent constraint letters
+are ignored.  As a special exception, an empty constraint string
+matches the @code{ALL_REGS} register class.  This may relieve ports
+of the burden of defining an @code{ALL_REGS} constraint letter just
+for these patterns.
+
+@cindex @code{movstrict@var{m}} instruction pattern
+@item @samp{movstrict@var{m}}
+Like @samp{mov@var{m}} except that if operand 0 is a @code{subreg}
+with mode @var{m} of a register whose natural mode is wider,
+the @samp{movstrict@var{m}} instruction is guaranteed not to alter
+any of the register except the part which belongs to mode @var{m}.
+
+@cindex @code{load_multiple} instruction pattern
+@item @samp{load_multiple}
+Load several consecutive memory locations into consecutive registers.
+Operand 0 is the first of the consecutive registers, operand 1
+is the first memory location, and operand 2 is a constant: the
+number of consecutive registers.
+
+Define this only if the target machine really has such an instruction;
+do not define this if the most efficient way of loading consecutive
+registers from memory is to do them one at a time.
+
+On some machines, there are restrictions as to which consecutive
+registers can be stored into memory, such as particular starting or
+ending register numbers or only a range of valid counts.  For those
+machines, use a @code{define_expand} (@pxref{Expander Definitions})
+and make the pattern fail if the restrictions are not met.
+
+Write the generated insn as a @code{parallel} with elements being a
+@code{set} of one register from the appropriate memory location (you may
+also need @code{use} or @code{clobber} elements).  Use a
+@code{match_parallel} (@pxref{RTL Template}) to recognize the insn.  See
+@file{a29k.md} and @file{rs6000.md} for examples of the use of this insn
+pattern.
+
+@cindex @samp{store_multiple} instruction pattern
+@item @samp{store_multiple}
+Similar to @samp{load_multiple}, but store several consecutive registers
+into consecutive memory locations.  Operand 0 is the first of the
+consecutive memory locations, operand 1 is the first register, and
+operand 2 is a constant: the number of consecutive registers.
+
+@cindex @code{push@var{m}} instruction pattern
+@item @samp{push@var{m}}
+Output an push instruction.  Operand 0 is value to push.  Used only when
+@code{PUSH_ROUNDING} is defined.  For historical reason, this pattern may be
+missing and in such case an @code{mov} expander is used instead, with a
+@code{MEM} expression forming the push operation.  The @code{mov} expander
+method is deprecated.
+
+@cindex @code{add@var{m}3} instruction pattern
+@item @samp{add@var{m}3}
+Add operand 2 and operand 1, storing the result in operand 0.  All operands
+must have mode @var{m}.  This can be used even on two-address machines, by
+means of constraints requiring operands 1 and 0 to be the same location.
+
+@cindex @code{sub@var{m}3} instruction pattern
+@cindex @code{mul@var{m}3} instruction pattern
+@cindex @code{div@var{m}3} instruction pattern
+@cindex @code{udiv@var{m}3} instruction pattern
+@cindex @code{mod@var{m}3} instruction pattern
+@cindex @code{umod@var{m}3} instruction pattern
+@cindex @code{smin@var{m}3} instruction pattern
+@cindex @code{smax@var{m}3} instruction pattern
+@cindex @code{umin@var{m}3} instruction pattern
+@cindex @code{umax@var{m}3} instruction pattern
+@cindex @code{and@var{m}3} instruction pattern
+@cindex @code{ior@var{m}3} instruction pattern
+@cindex @code{xor@var{m}3} instruction pattern
+@item @samp{sub@var{m}3}, @samp{mul@var{m}3}
+@itemx @samp{div@var{m}3}, @samp{udiv@var{m}3}, @samp{mod@var{m}3}, @samp{umod@var{m}3}
+@itemx @samp{smin@var{m}3}, @samp{smax@var{m}3}, @samp{umin@var{m}3}, @samp{umax@var{m}3}
+@itemx @samp{and@var{m}3}, @samp{ior@var{m}3}, @samp{xor@var{m}3}
+Similar, for other arithmetic operations.
+@cindex @code{min@var{m}3} instruction pattern
+@cindex @code{max@var{m}3} instruction pattern
+@itemx @samp{min@var{m}3}, @samp{max@var{m}3}
+Floating point min and max operations.  If both operands are zeros,
+or if either operand is NaN, then it is unspecified which of the two
+operands is returned as the result.
+
+
+@cindex @code{mulhisi3} instruction pattern
+@item @samp{mulhisi3}
+Multiply operands 1 and 2, which have mode @code{HImode}, and store
+a @code{SImode} product in operand 0.
+
+@cindex @code{mulqihi3} instruction pattern
+@cindex @code{mulsidi3} instruction pattern
+@item @samp{mulqihi3}, @samp{mulsidi3}
+Similar widening-multiplication instructions of other widths.
+
+@cindex @code{umulqihi3} instruction pattern
+@cindex @code{umulhisi3} instruction pattern
+@cindex @code{umulsidi3} instruction pattern
+@item @samp{umulqihi3}, @samp{umulhisi3}, @samp{umulsidi3}
+Similar widening-multiplication instructions that do unsigned
+multiplication.
+
+@cindex @code{smul@var{m}3_highpart} instruction pattern
+@item @samp{smul@var{m}3_highpart}
+Perform a signed multiplication of operands 1 and 2, which have mode
+@var{m}, and store the most significant half of the product in operand 0.
+The least significant half of the product is discarded.
+
+@cindex @code{umul@var{m}3_highpart} instruction pattern
+@item @samp{umul@var{m}3_highpart}
+Similar, but the multiplication is unsigned.
+
+@cindex @code{divmod@var{m}4} instruction pattern
+@item @samp{divmod@var{m}4}
+Signed division that produces both a quotient and a remainder.
+Operand 1 is divided by operand 2 to produce a quotient stored
+in operand 0 and a remainder stored in operand 3.
+
+For machines with an instruction that produces both a quotient and a
+remainder, provide a pattern for @samp{divmod@var{m}4} but do not
+provide patterns for @samp{div@var{m}3} and @samp{mod@var{m}3}.  This
+allows optimization in the relatively common case when both the quotient
+and remainder are computed.
+
+If an instruction that just produces a quotient or just a remainder
+exists and is more efficient than the instruction that produces both,
+write the output routine of @samp{divmod@var{m}4} to call
+@code{find_reg_note} and look for a @code{REG_UNUSED} note on the
+quotient or remainder and generate the appropriate instruction.
+
+@cindex @code{udivmod@var{m}4} instruction pattern
+@item @samp{udivmod@var{m}4}
+Similar, but does unsigned division.
+
+@cindex @code{ashl@var{m}3} instruction pattern
+@item @samp{ashl@var{m}3}
+Arithmetic-shift operand 1 left by a number of bits specified by operand
+2, and store the result in operand 0.  Here @var{m} is the mode of
+operand 0 and operand 1; operand 2's mode is specified by the
+instruction pattern, and the compiler will convert the operand to that
+mode before generating the instruction.
+
+@cindex @code{ashr@var{m}3} instruction pattern
+@cindex @code{lshr@var{m}3} instruction pattern
+@cindex @code{rotl@var{m}3} instruction pattern
+@cindex @code{rotr@var{m}3} instruction pattern
+@item @samp{ashr@var{m}3}, @samp{lshr@var{m}3}, @samp{rotl@var{m}3}, @samp{rotr@var{m}3}
+Other shift and rotate instructions, analogous to the
+@code{ashl@var{m}3} instructions.
+
+@cindex @code{neg@var{m}2} instruction pattern
+@item @samp{neg@var{m}2}
+Negate operand 1 and store the result in operand 0.
+
+@cindex @code{abs@var{m}2} instruction pattern
+@item @samp{abs@var{m}2}
+Store the absolute value of operand 1 into operand 0.
+
+@cindex @code{sqrt@var{m}2} instruction pattern
+@item @samp{sqrt@var{m}2}
+Store the square root of operand 1 into operand 0.
+
+The @code{sqrt} built-in function of C always uses the mode which
+corresponds to the C data type @code{double}.
+
+@cindex @code{ffs@var{m}2} instruction pattern
+@item @samp{ffs@var{m}2}
+Store into operand 0 one plus the index of the least significant 1-bit
+of operand 1.  If operand 1 is zero, store zero.  @var{m} is the mode
+of operand 0; operand 1's mode is specified by the instruction
+pattern, and the compiler will convert the operand to that mode before
+generating the instruction.
+
+The @code{ffs} built-in function of C always uses the mode which
+corresponds to the C data type @code{int}.
+
+@cindex @code{one_cmpl@var{m}2} instruction pattern
+@item @samp{one_cmpl@var{m}2}
+Store the bitwise-complement of operand 1 into operand 0.
+
+@cindex @code{cmp@var{m}} instruction pattern
+@item @samp{cmp@var{m}}
+Compare operand 0 and operand 1, and set the condition codes.
+The RTL pattern should look like this:
+
+@smallexample
+(set (cc0) (compare (match_operand:@var{m} 0 @dots{})
+                    (match_operand:@var{m} 1 @dots{})))
+@end smallexample
+
+@cindex @code{tst@var{m}} instruction pattern
+@item @samp{tst@var{m}}
+Compare operand 0 against zero, and set the condition codes.
+The RTL pattern should look like this:
+
+@smallexample
+(set (cc0) (match_operand:@var{m} 0 @dots{}))
+@end smallexample
+
+@samp{tst@var{m}} patterns should not be defined for machines that do
+not use @code{(cc0)}.  Doing so would confuse the optimizer since it
+would no longer be clear which @code{set} operations were comparisons.
+The @samp{cmp@var{m}} patterns should be used instead.
+
+@cindex @code{movstr@var{m}} instruction pattern
+@item @samp{movstr@var{m}}
+Block move instruction.  The addresses of the destination and source
+strings are the first two operands, and both are in mode @code{Pmode}.
+
+The number of bytes to move is the third operand, in mode @var{m}.
+Usually, you specify @code{word_mode} for @var{m}.  However, if you can
+generate better code knowing the range of valid lengths is smaller than
+those representable in a full word, you should provide a pattern with a
+mode corresponding to the range of values you can handle efficiently
+(e.g., @code{QImode} for values in the range 0--127; note we avoid numbers
+that appear negative) and also a pattern with @code{word_mode}.
+
+The fourth operand is the known shared alignment of the source and
+destination, in the form of a @code{const_int} rtx.  Thus, if the
+compiler knows that both source and destination are word-aligned,
+it may provide the value 4 for this operand.
+
+Descriptions of multiple @code{movstr@var{m}} patterns can only be
+beneficial if the patterns for smaller modes have fewer restrictions
+on their first, second and fourth operands.  Note that the mode @var{m}
+in @code{movstr@var{m}} does not impose any restriction on the mode of
+individually moved data units in the block.
+
+These patterns need not give special consideration to the possibility
+that the source and destination strings might overlap.
+
+@cindex @code{clrstr@var{m}} instruction pattern
+@item @samp{clrstr@var{m}}
+Block clear instruction.  The addresses of the destination string is the
+first operand, in mode @code{Pmode}.  The number of bytes to clear is
+the second operand, in mode @var{m}.  See @samp{movstr@var{m}} for
+a discussion of the choice of mode.
+
+The third operand is the known alignment of the destination, in the form
+of a @code{const_int} rtx.  Thus, if the compiler knows that the
+destination is word-aligned, it may provide the value 4 for this
+operand.
+
+The use for multiple @code{clrstr@var{m}} is as for @code{movstr@var{m}}.
+
+@cindex @code{cmpstr@var{m}} instruction pattern
+@item @samp{cmpstr@var{m}}
+Block compare instruction, with five operands.  Operand 0 is the output;
+it has mode @var{m}.  The remaining four operands are like the operands
+of @samp{movstr@var{m}}.  The two memory blocks specified are compared
+byte by byte in lexicographic order.  The effect of the instruction is
+to store a value in operand 0 whose sign indicates the result of the
+comparison.
+
+@cindex @code{strlen@var{m}} instruction pattern
+@item @samp{strlen@var{m}}
+Compute the length of a string, with three operands.
+Operand 0 is the result (of mode @var{m}), operand 1 is
+a @code{mem} referring to the first character of the string,
+operand 2 is the character to search for (normally zero),
+and operand 3 is a constant describing the known alignment
+of the beginning of the string.
+
+@cindex @code{float@var{mn}2} instruction pattern
+@item @samp{float@var{m}@var{n}2}
+Convert signed integer operand 1 (valid for fixed point mode @var{m}) to
+floating point mode @var{n} and store in operand 0 (which has mode
+@var{n}).
+
+@cindex @code{floatuns@var{mn}2} instruction pattern
+@item @samp{floatuns@var{m}@var{n}2}
+Convert unsigned integer operand 1 (valid for fixed point mode @var{m})
+to floating point mode @var{n} and store in operand 0 (which has mode
+@var{n}).
+
+@cindex @code{fix@var{mn}2} instruction pattern
+@item @samp{fix@var{m}@var{n}2}
+Convert operand 1 (valid for floating point mode @var{m}) to fixed
+point mode @var{n} as a signed number and store in operand 0 (which
+has mode @var{n}).  This instruction's result is defined only when
+the value of operand 1 is an integer.
+
+@cindex @code{fixuns@var{mn}2} instruction pattern
+@item @samp{fixuns@var{m}@var{n}2}
+Convert operand 1 (valid for floating point mode @var{m}) to fixed
+point mode @var{n} as an unsigned number and store in operand 0 (which
+has mode @var{n}).  This instruction's result is defined only when the
+value of operand 1 is an integer.
+
+@cindex @code{ftrunc@var{m}2} instruction pattern
+@item @samp{ftrunc@var{m}2}
+Convert operand 1 (valid for floating point mode @var{m}) to an
+integer value, still represented in floating point mode @var{m}, and
+store it in operand 0 (valid for floating point mode @var{m}).
+
+@cindex @code{fix_trunc@var{mn}2} instruction pattern
+@item @samp{fix_trunc@var{m}@var{n}2}
+Like @samp{fix@var{m}@var{n}2} but works for any floating point value
+of mode @var{m} by converting the value to an integer.
+
+@cindex @code{fixuns_trunc@var{mn}2} instruction pattern
+@item @samp{fixuns_trunc@var{m}@var{n}2}
+Like @samp{fixuns@var{m}@var{n}2} but works for any floating point
+value of mode @var{m} by converting the value to an integer.
+
+@cindex @code{trunc@var{mn}2} instruction pattern
+@item @samp{trunc@var{m}@var{n}2}
+Truncate operand 1 (valid for mode @var{m}) to mode @var{n} and
+store in operand 0 (which has mode @var{n}).  Both modes must be fixed
+point or both floating point.
+
+@cindex @code{extend@var{mn}2} instruction pattern
+@item @samp{extend@var{m}@var{n}2}
+Sign-extend operand 1 (valid for mode @var{m}) to mode @var{n} and
+store in operand 0 (which has mode @var{n}).  Both modes must be fixed
+point or both floating point.
+
+@cindex @code{zero_extend@var{mn}2} instruction pattern
+@item @samp{zero_extend@var{m}@var{n}2}
+Zero-extend operand 1 (valid for mode @var{m}) to mode @var{n} and
+store in operand 0 (which has mode @var{n}).  Both modes must be fixed
+point.
+
+@cindex @code{extv} instruction pattern
+@item @samp{extv}
+Extract a bit-field from operand 1 (a register or memory operand), where
+operand 2 specifies the width in bits and operand 3 the starting bit,
+and store it in operand 0.  Operand 0 must have mode @code{word_mode}.
+Operand 1 may have mode @code{byte_mode} or @code{word_mode}; often
+@code{word_mode} is allowed only for registers.  Operands 2 and 3 must
+be valid for @code{word_mode}.
+
+The RTL generation pass generates this instruction only with constants
+for operands 2 and 3.
+
+The bit-field value is sign-extended to a full word integer
+before it is stored in operand 0.
+
+@cindex @code{extzv} instruction pattern
+@item @samp{extzv}
+Like @samp{extv} except that the bit-field value is zero-extended.
+
+@cindex @code{insv} instruction pattern
+@item @samp{insv}
+Store operand 3 (which must be valid for @code{word_mode}) into a
+bit-field in operand 0, where operand 1 specifies the width in bits and
+operand 2 the starting bit.  Operand 0 may have mode @code{byte_mode} or
+@code{word_mode}; often @code{word_mode} is allowed only for registers.
+Operands 1 and 2 must be valid for @code{word_mode}.
+
+The RTL generation pass generates this instruction only with constants
+for operands 1 and 2.
+
+@cindex @code{mov@var{mode}cc} instruction pattern
+@item @samp{mov@var{mode}cc}
+Conditionally move operand 2 or operand 3 into operand 0 according to the
+comparison in operand 1.  If the comparison is true, operand 2 is moved
+into operand 0, otherwise operand 3 is moved.
+
+The mode of the operands being compared need not be the same as the operands
+being moved.  Some machines, sparc64 for example, have instructions that
+conditionally move an integer value based on the floating point condition
+codes and vice versa.
+
+If the machine does not have conditional move instructions, do not
+define these patterns.
+
+@cindex @code{s@var{cond}} instruction pattern
+@item @samp{s@var{cond}}
+Store zero or nonzero in the operand according to the condition codes.
+Value stored is nonzero iff the condition @var{cond} is true.
+@var{cond} is the name of a comparison operation expression code, such
+as @code{eq}, @code{lt} or @code{leu}.
+
+You specify the mode that the operand must have when you write the
+@code{match_operand} expression.  The compiler automatically sees
+which mode you have used and supplies an operand of that mode.
+
+The value stored for a true condition must have 1 as its low bit, or
+else must be negative.  Otherwise the instruction is not suitable and
+you should omit it from the machine description.  You describe to the
+compiler exactly which value is stored by defining the macro
+@code{STORE_FLAG_VALUE} (@pxref{Misc}).  If a description cannot be
+found that can be used for all the @samp{s@var{cond}} patterns, you
+should omit those operations from the machine description.
+
+These operations may fail, but should do so only in relatively
+uncommon cases; if they would fail for common cases involving
+integer comparisons, it is best to omit these patterns.
+
+If these operations are omitted, the compiler will usually generate code
+that copies the constant one to the target and branches around an
+assignment of zero to the target.  If this code is more efficient than
+the potential instructions used for the @samp{s@var{cond}} pattern
+followed by those required to convert the result into a 1 or a zero in
+@code{SImode}, you should omit the @samp{s@var{cond}} operations from
+the machine description.
+
+@cindex @code{b@var{cond}} instruction pattern
+@item @samp{b@var{cond}}
+Conditional branch instruction.  Operand 0 is a @code{label_ref} that
+refers to the label to jump to.  Jump if the condition codes meet
+condition @var{cond}.
+
+Some machines do not follow the model assumed here where a comparison
+instruction is followed by a conditional branch instruction.  In that
+case, the @samp{cmp@var{m}} (and @samp{tst@var{m}}) patterns should
+simply store the operands away and generate all the required insns in a
+@code{define_expand} (@pxref{Expander Definitions}) for the conditional
+branch operations.  All calls to expand @samp{b@var{cond}} patterns are
+immediately preceded by calls to expand either a @samp{cmp@var{m}}
+pattern or a @samp{tst@var{m}} pattern.
+
+Machines that use a pseudo register for the condition code value, or
+where the mode used for the comparison depends on the condition being
+tested, should also use the above mechanism.  @xref{Jump Patterns}.
+
+The above discussion also applies to the @samp{mov@var{mode}cc} and
+@samp{s@var{cond}} patterns.
+
+@cindex @code{jump} instruction pattern
+@item @samp{jump}
+A jump inside a function; an unconditional branch.  Operand 0 is the
+@code{label_ref} of the label to jump to.  This pattern name is mandatory
+on all machines.
+
+@cindex @code{call} instruction pattern
+@item @samp{call}
+Subroutine call instruction returning no value.  Operand 0 is the
+function to call; operand 1 is the number of bytes of arguments pushed
+as a @code{const_int}; operand 2 is the number of registers used as
+operands.
+
+On most machines, operand 2 is not actually stored into the RTL
+pattern.  It is supplied for the sake of some RISC machines which need
+to put this information into the assembler code; they can put it in
+the RTL instead of operand 1.
+
+Operand 0 should be a @code{mem} RTX whose address is the address of the
+function.  Note, however, that this address can be a @code{symbol_ref}
+expression even if it would not be a legitimate memory address on the
+target machine.  If it is also not a valid argument for a call
+instruction, the pattern for this operation should be a
+@code{define_expand} (@pxref{Expander Definitions}) that places the
+address into a register and uses that register in the call instruction.
+
+@cindex @code{call_value} instruction pattern
+@item @samp{call_value}
+Subroutine call instruction returning a value.  Operand 0 is the hard
+register in which the value is returned.  There are three more
+operands, the same as the three operands of the @samp{call}
+instruction (but with numbers increased by one).
+
+Subroutines that return @code{BLKmode} objects use the @samp{call}
+insn.
+
+@cindex @code{call_pop} instruction pattern
+@cindex @code{call_value_pop} instruction pattern
+@item @samp{call_pop}, @samp{call_value_pop}
+Similar to @samp{call} and @samp{call_value}, except used if defined and
+if @code{RETURN_POPS_ARGS} is nonzero.  They should emit a @code{parallel}
+that contains both the function call and a @code{set} to indicate the
+adjustment made to the frame pointer.
+
+For machines where @code{RETURN_POPS_ARGS} can be nonzero, the use of these
+patterns increases the number of functions for which the frame pointer
+can be eliminated, if desired.
+
+@cindex @code{untyped_call} instruction pattern
+@item @samp{untyped_call}
+Subroutine call instruction returning a value of any type.  Operand 0 is
+the function to call; operand 1 is a memory location where the result of
+calling the function is to be stored; operand 2 is a @code{parallel}
+expression where each element is a @code{set} expression that indicates
+the saving of a function return value into the result block.
+
+This instruction pattern should be defined to support
+@code{__builtin_apply} on machines where special instructions are needed
+to call a subroutine with arbitrary arguments or to save the value
+returned.  This instruction pattern is required on machines that have
+multiple registers that can hold a return value
+(i.e.@: @code{FUNCTION_VALUE_REGNO_P} is true for more than one register).
+
+@cindex @code{return} instruction pattern
+@item @samp{return}
+Subroutine return instruction.  This instruction pattern name should be
+defined only if a single instruction can do all the work of returning
+from a function.
+
+Like the @samp{mov@var{m}} patterns, this pattern is also used after the
+RTL generation phase.  In this case it is to support machines where
+multiple instructions are usually needed to return from a function, but
+some class of functions only requires one instruction to implement a
+return.  Normally, the applicable functions are those which do not need
+to save any registers or allocate stack space.
+
+@findex reload_completed
+@findex leaf_function_p
+For such machines, the condition specified in this pattern should only
+be true when @code{reload_completed} is nonzero and the function's
+epilogue would only be a single instruction.  For machines with register
+windows, the routine @code{leaf_function_p} may be used to determine if
+a register window push is required.
+
+Machines that have conditional return instructions should define patterns
+such as
+
+@smallexample
+(define_insn ""
+  [(set (pc)
+        (if_then_else (match_operator
+                         0 "comparison_operator"
+                         [(cc0) (const_int 0)])
+                      (return)
+                      (pc)))]
+  "@var{condition}"
+  "@dots{}")
+@end smallexample
+
+where @var{condition} would normally be the same condition specified on the
+named @samp{return} pattern.
+
+@cindex @code{untyped_return} instruction pattern
+@item @samp{untyped_return}
+Untyped subroutine return instruction.  This instruction pattern should
+be defined to support @code{__builtin_return} on machines where special
+instructions are needed to return a value of any type.
+
+Operand 0 is a memory location where the result of calling a function
+with @code{__builtin_apply} is stored; operand 1 is a @code{parallel}
+expression where each element is a @code{set} expression that indicates
+the restoring of a function return value from the result block.
+
+@cindex @code{nop} instruction pattern
+@item @samp{nop}
+No-op instruction.  This instruction pattern name should always be defined
+to output a no-op in assembler code.  @code{(const_int 0)} will do as an
+RTL pattern.
+
+@cindex @code{indirect_jump} instruction pattern
+@item @samp{indirect_jump}
+An instruction to jump to an address which is operand zero.
+This pattern name is mandatory on all machines.
+
+@cindex @code{casesi} instruction pattern
+@item @samp{casesi}
+Instruction to jump through a dispatch table, including bounds checking.
+This instruction takes five operands:
+
+@enumerate
+@item
+The index to dispatch on, which has mode @code{SImode}.
+
+@item
+The lower bound for indices in the table, an integer constant.
+
+@item
+The total range of indices in the table---the largest index
+minus the smallest one (both inclusive).
+
+@item
+A label that precedes the table itself.
+
+@item
+A label to jump to if the index has a value outside the bounds.
+(If the machine-description macro @code{CASE_DROPS_THROUGH} is defined,
+then an out-of-bounds index drops through to the code following
+the jump table instead of jumping to this label.  In that case,
+this label is not actually used by the @samp{casesi} instruction,
+but it is always provided as an operand.)
+@end enumerate
+
+The table is a @code{addr_vec} or @code{addr_diff_vec} inside of a
+@code{jump_insn}.  The number of elements in the table is one plus the
+difference between the upper bound and the lower bound.
+
+@cindex @code{tablejump} instruction pattern
+@item @samp{tablejump}
+Instruction to jump to a variable address.  This is a low-level
+capability which can be used to implement a dispatch table when there
+is no @samp{casesi} pattern.
+
+This pattern requires two operands: the address or offset, and a label
+which should immediately precede the jump table.  If the macro
+@code{CASE_VECTOR_PC_RELATIVE} evaluates to a nonzero value then the first
+operand is an offset which counts from the address of the table; otherwise,
+it is an absolute address to jump to.  In either case, the first operand has
+mode @code{Pmode}.
+
+The @samp{tablejump} insn is always the last insn before the jump
+table it uses.  Its assembler code normally has no need to use the
+second operand, but you should incorporate it in the RTL pattern so
+that the jump optimizer will not delete the table as unreachable code.
+
+
+@cindex @code{decrement_and_branch_until_zero} instruction pattern
+@item @samp{decrement_and_branch_until_zero}
+Conditional branch instruction that decrements a register and
+jumps if the register is nonzero.  Operand 0 is the register to
+decrement and test; operand 1 is the label to jump to if the
+register is nonzero.  @xref{Looping Patterns}.
+
+This optional instruction pattern is only used by the combiner,
+typically for loops reversed by the loop optimizer when strength
+reduction is enabled.
+
+@cindex @code{doloop_end} instruction pattern
+@item @samp{doloop_end}
+Conditional branch instruction that decrements a register and jumps if
+the register is nonzero.  This instruction takes five operands: Operand
+0 is the register to decrement and test; operand 1 is the number of loop
+iterations as a @code{const_int} or @code{const0_rtx} if this cannot be
+determined until run-time; operand 2 is the actual or estimated maximum
+number of iterations as a @code{const_int}; operand 3 is the number of
+enclosed loops as a @code{const_int} (an innermost loop has a value of
+1); operand 4 is the label to jump to if the register is nonzero.
+@xref{Looping Patterns}.
+
+This optional instruction pattern should be defined for machines with
+low-overhead looping instructions as the loop optimizer will try to
+modify suitable loops to utilize it.  If nested low-overhead looping is
+not supported, use a @code{define_expand} (@pxref{Expander Definitions})
+and make the pattern fail if operand 3 is not @code{const1_rtx}.
+Similarly, if the actual or estimated maximum number of iterations is
+too large for this instruction, make it fail.
+
+@cindex @code{doloop_begin} instruction pattern
+@item @samp{doloop_begin}
+Companion instruction to @code{doloop_end} required for machines that
+need to perform some initialization, such as loading special registers
+used by a low-overhead looping instruction.  If initialization insns do
+not always need to be emitted, use a @code{define_expand}
+(@pxref{Expander Definitions}) and make it fail.
+
+
+@cindex @code{canonicalize_funcptr_for_compare} instruction pattern
+@item @samp{canonicalize_funcptr_for_compare}
+Canonicalize the function pointer in operand 1 and store the result
+into operand 0.
+
+Operand 0 is always a @code{reg} and has mode @code{Pmode}; operand 1
+may be a @code{reg}, @code{mem}, @code{symbol_ref}, @code{const_int}, etc
+and also has mode @code{Pmode}.
+
+Canonicalization of a function pointer usually involves computing
+the address of the function which would be called if the function
+pointer were used in an indirect call.
+
+Only define this pattern if function pointers on the target machine
+can have different values but still call the same function when
+used in an indirect call.
+
+@cindex @code{save_stack_block} instruction pattern
+@cindex @code{save_stack_function} instruction pattern
+@cindex @code{save_stack_nonlocal} instruction pattern
+@cindex @code{restore_stack_block} instruction pattern
+@cindex @code{restore_stack_function} instruction pattern
+@cindex @code{restore_stack_nonlocal} instruction pattern
+@item @samp{save_stack_block}
+@itemx @samp{save_stack_function}
+@itemx @samp{save_stack_nonlocal}
+@itemx @samp{restore_stack_block}
+@itemx @samp{restore_stack_function}
+@itemx @samp{restore_stack_nonlocal}
+Most machines save and restore the stack pointer by copying it to or
+from an object of mode @code{Pmode}.  Do not define these patterns on
+such machines.
+
+Some machines require special handling for stack pointer saves and
+restores.  On those machines, define the patterns corresponding to the
+non-standard cases by using a @code{define_expand} (@pxref{Expander
+Definitions}) that produces the required insns.  The three types of
+saves and restores are:
+
+@enumerate
+@item
+@samp{save_stack_block} saves the stack pointer at the start of a block
+that allocates a variable-sized object, and @samp{restore_stack_block}
+restores the stack pointer when the block is exited.
+
+@item
+@samp{save_stack_function} and @samp{restore_stack_function} do a
+similar job for the outermost block of a function and are used when the
+function allocates variable-sized objects or calls @code{alloca}.  Only
+the epilogue uses the restored stack pointer, allowing a simpler save or
+restore sequence on some machines.
+
+@item
+@samp{save_stack_nonlocal} is used in functions that contain labels
+branched to by nested functions.  It saves the stack pointer in such a
+way that the inner function can use @samp{restore_stack_nonlocal} to
+restore the stack pointer.  The compiler generates code to restore the
+frame and argument pointer registers, but some machines require saving
+and restoring additional data such as register window information or
+stack backchains.  Place insns in these patterns to save and restore any
+such required data.
+@end enumerate
+
+When saving the stack pointer, operand 0 is the save area and operand 1
+is the stack pointer.  The mode used to allocate the save area defaults
+to @code{Pmode} but you can override that choice by defining the
+@code{STACK_SAVEAREA_MODE} macro (@pxref{Storage Layout}).  You must
+specify an integral mode, or @code{VOIDmode} if no save area is needed
+for a particular type of save (either because no save is needed or
+because a machine-specific save area can be used).  Operand 0 is the
+stack pointer and operand 1 is the save area for restore operations.  If
+@samp{save_stack_block} is defined, operand 0 must not be
+@code{VOIDmode} since these saves can be arbitrarily nested.
+
+A save area is a @code{mem} that is at a constant offset from
+@code{virtual_stack_vars_rtx} when the stack pointer is saved for use by
+nonlocal gotos and a @code{reg} in the other two cases.
+
+@cindex @code{allocate_stack} instruction pattern
+@item @samp{allocate_stack}
+Subtract (or add if @code{STACK_GROWS_DOWNWARD} is undefined) operand 1 from
+the stack pointer to create space for dynamically allocated data.
+
+Store the resultant pointer to this space into operand 0.  If you
+are allocating space from the main stack, do this by emitting a
+move insn to copy @code{virtual_stack_dynamic_rtx} to operand 0.
+If you are allocating the space elsewhere, generate code to copy the
+location of the space to operand 0.  In the latter case, you must
+ensure this space gets freed when the corresponding space on the main
+stack is free.
+
+Do not define this pattern if all that must be done is the subtraction.
+Some machines require other operations such as stack probes or
+maintaining the back chain.  Define this pattern to emit those
+operations in addition to updating the stack pointer.
+
+@cindex @code{probe} instruction pattern
+@item @samp{probe}
+Some machines require instructions to be executed after space is
+allocated from the stack, for example to generate a reference at
+the bottom of the stack.
+
+If you need to emit instructions before the stack has been adjusted,
+put them into the @samp{allocate_stack} pattern.  Otherwise, define
+this pattern to emit the required instructions.
+
+No operands are provided.
+
+@cindex @code{check_stack} instruction pattern
+@item @samp{check_stack}
+If stack checking cannot be done on your system by probing the stack with
+a load or store instruction (@pxref{Stack Checking}), define this pattern
+to perform the needed check and signaling an error if the stack
+has overflowed.  The single operand is the location in the stack furthest
+from the current stack pointer that you need to validate.  Normally,
+on machines where this pattern is needed, you would obtain the stack
+limit from a global or thread-specific variable or register.
+
+@cindex @code{nonlocal_goto} instruction pattern
+@item @samp{nonlocal_goto}
+Emit code to generate a non-local goto, e.g., a jump from one function
+to a label in an outer function.  This pattern has four arguments,
+each representing a value to be used in the jump.  The first
+argument is to be loaded into the frame pointer, the second is
+the address to branch to (code to dispatch to the actual label),
+the third is the address of a location where the stack is saved,
+and the last is the address of the label, to be placed in the
+location for the incoming static chain.
+
+On most machines you need not define this pattern, since GCC will
+already generate the correct code, which is to load the frame pointer
+and static chain, restore the stack (using the
+@samp{restore_stack_nonlocal} pattern, if defined), and jump indirectly
+to the dispatcher.  You need only define this pattern if this code will
+not work on your machine.
+
+@cindex @code{nonlocal_goto_receiver} instruction pattern
+@item @samp{nonlocal_goto_receiver}
+This pattern, if defined, contains code needed at the target of a
+nonlocal goto after the code already generated by GCC@.  You will not
+normally need to define this pattern.  A typical reason why you might
+need this pattern is if some value, such as a pointer to a global table,
+must be restored when the frame pointer is restored.  Note that a nonlocal
+goto only occurs within a unit-of-translation, so a global table pointer
+that is shared by all functions of a given module need not be restored.
+There are no arguments.
+
+@cindex @code{exception_receiver} instruction pattern
+@item @samp{exception_receiver}
+This pattern, if defined, contains code needed at the site of an
+exception handler that isn't needed at the site of a nonlocal goto.  You
+will not normally need to define this pattern.  A typical reason why you
+might need this pattern is if some value, such as a pointer to a global
+table, must be restored after control flow is branched to the handler of
+an exception.  There are no arguments.
+
+@cindex @code{builtin_setjmp_setup} instruction pattern
+@item @samp{builtin_setjmp_setup}
+This pattern, if defined, contains additional code needed to initialize
+the @code{jmp_buf}.  You will not normally need to define this pattern.
+A typical reason why you might need this pattern is if some value, such
+as a pointer to a global table, must be restored.  Though it is
+preferred that the pointer value be recalculated if possible (given the
+address of a label for instance).  The single argument is a pointer to
+the @code{jmp_buf}.  Note that the buffer is five words long and that
+the first three are normally used by the generic mechanism.
+
+@cindex @code{builtin_setjmp_receiver} instruction pattern
+@item @samp{builtin_setjmp_receiver}
+This pattern, if defined, contains code needed at the site of an
+built-in setjmp that isn't needed at the site of a nonlocal goto.  You
+will not normally need to define this pattern.  A typical reason why you
+might need this pattern is if some value, such as a pointer to a global
+table, must be restored.  It takes one argument, which is the label
+to which builtin_longjmp transfered control; this pattern may be emitted
+at a small offset from that label.
+
+@cindex @code{builtin_longjmp} instruction pattern
+@item @samp{builtin_longjmp}
+This pattern, if defined, performs the entire action of the longjmp.
+You will not normally need to define this pattern unless you also define
+@code{builtin_setjmp_setup}.  The single argument is a pointer to the
+@code{jmp_buf}.
+
+@cindex @code{eh_return} instruction pattern
+@item @samp{eh_return}
+This pattern, if defined, affects the way @code{__builtin_eh_return},
+and thence the call frame exception handling library routines, are
+built.  It is intended to handle non-trivial actions needed along
+the abnormal return path.
+
+The pattern takes two arguments.  The first is an offset to be applied
+to the stack pointer.  It will have been copied to some appropriate
+location (typically @code{EH_RETURN_STACKADJ_RTX}) which will survive
+until after reload to when the normal epilogue is generated.
+The second argument is the address of the exception handler to which
+the function should return.  This will normally need to copied by the
+pattern to some special register or memory location.
+
+This pattern only needs to be defined if call frame exception handling
+is to be used, and simple moves involving @code{EH_RETURN_STACKADJ_RTX}
+and @code{EH_RETURN_HANDLER_RTX} are not sufficient.
+
+@cindex @code{prologue} instruction pattern
+@anchor{prologue instruction pattern}
+@item @samp{prologue}
+This pattern, if defined, emits RTL for entry to a function.  The function
+entry is responsible for setting up the stack frame, initializing the frame
+pointer register, saving callee saved registers, etc.
+
+Using a prologue pattern is generally preferred over defining
+@code{TARGET_ASM_FUNCTION_PROLOGUE} to emit assembly code for the prologue.
+
+The @code{prologue} pattern is particularly useful for targets which perform
+instruction scheduling.
+
+@cindex @code{epilogue} instruction pattern
+@anchor{epilogue instruction pattern}
+@item @samp{epilogue}
+This pattern emits RTL for exit from a function.  The function
+exit is responsible for deallocating the stack frame, restoring callee saved
+registers and emitting the return instruction.
+
+Using an epilogue pattern is generally preferred over defining
+@code{TARGET_ASM_FUNCTION_EPILOGUE} to emit assembly code for the epilogue.
+
+The @code{epilogue} pattern is particularly useful for targets which perform
+instruction scheduling or which have delay slots for their return instruction.
+
+@cindex @code{sibcall_epilogue} instruction pattern
+@item @samp{sibcall_epilogue}
+This pattern, if defined, emits RTL for exit from a function without the final
+branch back to the calling function.  This pattern will be emitted before any
+sibling call (aka tail call) sites.
+
+The @code{sibcall_epilogue} pattern must not clobber any arguments used for
+parameter passing or any stack slots for arguments passed to the current
+function.
+
+@cindex @code{trap} instruction pattern
+@item @samp{trap}
+This pattern, if defined, signals an error, typically by causing some
+kind of signal to be raised.  Among other places, it is used by the Java
+front end to signal `invalid array index' exceptions.
+
+@cindex @code{conditional_trap} instruction pattern
+@item @samp{conditional_trap}
+Conditional trap instruction.  Operand 0 is a piece of RTL which
+performs a comparison.  Operand 1 is the trap code, an integer.
+
+A typical @code{conditional_trap} pattern looks like
+
+@smallexample
+(define_insn "conditional_trap"
+  [(trap_if (match_operator 0 "trap_operator"
+             [(cc0) (const_int 0)])
+            (match_operand 1 "const_int_operand" "i"))]
+  ""
+  "@dots{}")
+@end smallexample
+
+@cindex @code{prefetch} instruction pattern
+@item @samp{prefetch}
+
+This pattern, if defined, emits code for a non-faulting data prefetch
+instruction.  Operand 0 is the address of the memory to prefetch.  Operand 1
+is a constant 1 if the prefetch is preparing for a write to the memory
+address, or a constant 0 otherwise.  Operand 2 is the expected degree of
+temporal locality of the data and is a value between 0 and 3, inclusive; 0
+means that the data has no temporal locality, so it need not be left in the
+cache after the access; 3 means that the data has a high degree of temporal
+locality and should be left in all levels of cache possible;  1 and 2 mean,
+respectively, a low or moderate degree of temporal locality.
+
+Targets that do not support write prefetches or locality hints can ignore
+the values of operands 1 and 2.
+
+@cindex @code{cycle_display} instruction pattern
+@item @samp{cycle_display}
+
+This pattern, if present, will be emitted by the instruction scheduler at
+the beginning of each new clock cycle.  This can be used for annotating the
+assembler output with cycle counts.  Operand 0 is a @code{const_int} that
+holds the clock cycle.
+
+@end table
+
+@node Pattern Ordering
+@section When the Order of Patterns Matters
+@cindex Pattern Ordering
+@cindex Ordering of Patterns
+
+Sometimes an insn can match more than one instruction pattern.  Then the
+pattern that appears first in the machine description is the one used.
+Therefore, more specific patterns (patterns that will match fewer things)
+and faster instructions (those that will produce better code when they
+do match) should usually go first in the description.
+
+In some cases the effect of ordering the patterns can be used to hide
+a pattern when it is not valid.  For example, the 68000 has an
+instruction for converting a fullword to floating point and another
+for converting a byte to floating point.  An instruction converting
+an integer to floating point could match either one.  We put the
+pattern to convert the fullword first to make sure that one will
+be used rather than the other.  (Otherwise a large integer might
+be generated as a single-byte immediate quantity, which would not work.)
+Instead of using this pattern ordering it would be possible to make the
+pattern for convert-a-byte smart enough to deal properly with any
+constant value.
+
+@node Dependent Patterns
+@section Interdependence of Patterns
+@cindex Dependent Patterns
+@cindex Interdependence of Patterns
+
+Every machine description must have a named pattern for each of the
+conditional branch names @samp{b@var{cond}}.  The recognition template
+must always have the form
+
+@example
+(set (pc)
+     (if_then_else (@var{cond} (cc0) (const_int 0))
+                   (label_ref (match_operand 0 "" ""))
+                   (pc)))
+@end example
+
+@noindent
+In addition, every machine description must have an anonymous pattern
+for each of the possible reverse-conditional branches.  Their templates
+look like
+
+@example
+(set (pc)
+     (if_then_else (@var{cond} (cc0) (const_int 0))
+                   (pc)
+                   (label_ref (match_operand 0 "" ""))))
+@end example
+
+@noindent
+They are necessary because jump optimization can turn direct-conditional
+branches into reverse-conditional branches.
+
+It is often convenient to use the @code{match_operator} construct to
+reduce the number of patterns that must be specified for branches.  For
+example,
+
+@example
+(define_insn ""
+  [(set (pc)
+        (if_then_else (match_operator 0 "comparison_operator"
+                                      [(cc0) (const_int 0)])
+                      (pc)
+                      (label_ref (match_operand 1 "" ""))))]
+  "@var{condition}"
+  "@dots{}")
+@end example
+
+In some cases machines support instructions identical except for the
+machine mode of one or more operands.  For example, there may be
+``sign-extend halfword'' and ``sign-extend byte'' instructions whose
+patterns are
+
+@example
+(set (match_operand:SI 0 @dots{})
+     (extend:SI (match_operand:HI 1 @dots{})))
+
+(set (match_operand:SI 0 @dots{})
+     (extend:SI (match_operand:QI 1 @dots{})))
+@end example
+
+@noindent
+Constant integers do not specify a machine mode, so an instruction to
+extend a constant value could match either pattern.  The pattern it
+actually will match is the one that appears first in the file.  For correct
+results, this must be the one for the widest possible mode (@code{HImode},
+here).  If the pattern matches the @code{QImode} instruction, the results
+will be incorrect if the constant value does not actually fit that mode.
+
+Such instructions to extend constants are rarely generated because they are
+optimized away, but they do occasionally happen in nonoptimized
+compilations.
+
+If a constraint in a pattern allows a constant, the reload pass may
+replace a register with a constant permitted by the constraint in some
+cases.  Similarly for memory references.  Because of this substitution,
+you should not provide separate patterns for increment and decrement
+instructions.  Instead, they should be generated from the same pattern
+that supports register-register add insns by examining the operands and
+generating the appropriate machine instruction.
+
+@node Jump Patterns
+@section Defining Jump Instruction Patterns
+@cindex jump instruction patterns
+@cindex defining jump instruction patterns
+
+For most machines, GCC assumes that the machine has a condition code.
+A comparison insn sets the condition code, recording the results of both
+signed and unsigned comparison of the given operands.  A separate branch
+insn tests the condition code and branches or not according its value.
+The branch insns come in distinct signed and unsigned flavors.  Many
+common machines, such as the VAX, the 68000 and the 32000, work this
+way.
+
+Some machines have distinct signed and unsigned compare instructions, and
+only one set of conditional branch instructions.  The easiest way to handle
+these machines is to treat them just like the others until the final stage
+where assembly code is written.  At this time, when outputting code for the
+compare instruction, peek ahead at the following branch using
+@code{next_cc0_user (insn)}.  (The variable @code{insn} refers to the insn
+being output, in the output-writing code in an instruction pattern.)  If
+the RTL says that is an unsigned branch, output an unsigned compare;
+otherwise output a signed compare.  When the branch itself is output, you
+can treat signed and unsigned branches identically.
+
+The reason you can do this is that GCC always generates a pair of
+consecutive RTL insns, possibly separated by @code{note} insns, one to
+set the condition code and one to test it, and keeps the pair inviolate
+until the end.
+
+To go with this technique, you must define the machine-description macro
+@code{NOTICE_UPDATE_CC} to do @code{CC_STATUS_INIT}; in other words, no
+compare instruction is superfluous.
+
+Some machines have compare-and-branch instructions and no condition code.
+A similar technique works for them.  When it is time to ``output'' a
+compare instruction, record its operands in two static variables.  When
+outputting the branch-on-condition-code instruction that follows, actually
+output a compare-and-branch instruction that uses the remembered operands.
+
+It also works to define patterns for compare-and-branch instructions.
+In optimizing compilation, the pair of compare and branch instructions
+will be combined according to these patterns.  But this does not happen
+if optimization is not requested.  So you must use one of the solutions
+above in addition to any special patterns you define.
+
+In many RISC machines, most instructions do not affect the condition
+code and there may not even be a separate condition code register.  On
+these machines, the restriction that the definition and use of the
+condition code be adjacent insns is not necessary and can prevent
+important optimizations.  For example, on the IBM RS/6000, there is a
+delay for taken branches unless the condition code register is set three
+instructions earlier than the conditional branch.  The instruction
+scheduler cannot perform this optimization if it is not permitted to
+separate the definition and use of the condition code register.
+
+On these machines, do not use @code{(cc0)}, but instead use a register
+to represent the condition code.  If there is a specific condition code
+register in the machine, use a hard register.  If the condition code or
+comparison result can be placed in any general register, or if there are
+multiple condition registers, use a pseudo register.
+
+@findex prev_cc0_setter
+@findex next_cc0_user
+On some machines, the type of branch instruction generated may depend on
+the way the condition code was produced; for example, on the 68k and
+Sparc, setting the condition code directly from an add or subtract
+instruction does not clear the overflow bit the way that a test
+instruction does, so a different branch instruction must be used for
+some conditional branches.  For machines that use @code{(cc0)}, the set
+and use of the condition code must be adjacent (separated only by
+@code{note} insns) allowing flags in @code{cc_status} to be used.
+(@xref{Condition Code}.)  Also, the comparison and branch insns can be
+located from each other by using the functions @code{prev_cc0_setter}
+and @code{next_cc0_user}.
+
+However, this is not true on machines that do not use @code{(cc0)}.  On
+those machines, no assumptions can be made about the adjacency of the
+compare and branch insns and the above methods cannot be used.  Instead,
+we use the machine mode of the condition code register to record
+different formats of the condition code register.
+
+Registers used to store the condition code value should have a mode that
+is in class @code{MODE_CC}.  Normally, it will be @code{CCmode}.  If
+additional modes are required (as for the add example mentioned above in
+the Sparc), define the macro @code{EXTRA_CC_MODES} to list the
+additional modes required (@pxref{Condition Code}).  Also define
+@code{SELECT_CC_MODE} to choose a mode given an operand of a compare.
+
+If it is known during RTL generation that a different mode will be
+required (for example, if the machine has separate compare instructions
+for signed and unsigned quantities, like most IBM processors), they can
+be specified at that time.
+
+If the cases that require different modes would be made by instruction
+combination, the macro @code{SELECT_CC_MODE} determines which machine
+mode should be used for the comparison result.  The patterns should be
+written using that mode.  To support the case of the add on the Sparc
+discussed above, we have the pattern
+
+@smallexample
+(define_insn ""
+  [(set (reg:CC_NOOV 0)
+        (compare:CC_NOOV
+          (plus:SI (match_operand:SI 0 "register_operand" "%r")
+                   (match_operand:SI 1 "arith_operand" "rI"))
+          (const_int 0)))]
+  ""
+  "@dots{}")
+@end smallexample
+
+The @code{SELECT_CC_MODE} macro on the Sparc returns @code{CC_NOOVmode}
+for comparisons whose argument is a @code{plus}.
+
+@node Looping Patterns
+@section Defining Looping Instruction Patterns
+@cindex looping instruction patterns
+@cindex defining looping instruction patterns
+
+Some machines have special jump instructions that can be utilised to
+make loops more efficient.  A common example is the 68000 @samp{dbra}
+instruction which performs a decrement of a register and a branch if the
+result was greater than zero.  Other machines, in particular digital
+signal processors (DSPs), have special block repeat instructions to
+provide low-overhead loop support.  For example, the TI TMS320C3x/C4x
+DSPs have a block repeat instruction that loads special registers to
+mark the top and end of a loop and to count the number of loop
+iterations.  This avoids the need for fetching and executing a
+@samp{dbra}-like instruction and avoids pipeline stalls associated with
+the jump.
+
+GCC has three special named patterns to support low overhead looping.
+They are @samp{decrement_and_branch_until_zero}, @samp{doloop_begin},
+and @samp{doloop_end}.  The first pattern,
+@samp{decrement_and_branch_until_zero}, is not emitted during RTL
+generation but may be emitted during the instruction combination phase.
+This requires the assistance of the loop optimizer, using information
+collected during strength reduction, to reverse a loop to count down to
+zero.  Some targets also require the loop optimizer to add a
+@code{REG_NONNEG} note to indicate that the iteration count is always
+positive.  This is needed if the target performs a signed loop
+termination test.  For example, the 68000 uses a pattern similar to the
+following for its @code{dbra} instruction:
+
+@smallexample
+@group
+(define_insn "decrement_and_branch_until_zero"
+  [(set (pc)
+	(if_then_else
+	  (ge (plus:SI (match_operand:SI 0 "general_operand" "+d*am")
+		       (const_int -1))
+	      (const_int 0))
+	  (label_ref (match_operand 1 "" ""))
+	  (pc)))
+   (set (match_dup 0)
+	(plus:SI (match_dup 0)
+		 (const_int -1)))]
+  "find_reg_note (insn, REG_NONNEG, 0)"
+  "@dots{}")
+@end group
+@end smallexample
+
+Note that since the insn is both a jump insn and has an output, it must
+deal with its own reloads, hence the `m' constraints.  Also note that
+since this insn is generated by the instruction combination phase
+combining two sequential insns together into an implicit parallel insn,
+the iteration counter needs to be biased by the same amount as the
+decrement operation, in this case @minus{}1.  Note that the following similar
+pattern will not be matched by the combiner.
+
+@smallexample
+@group
+(define_insn "decrement_and_branch_until_zero"
+  [(set (pc)
+	(if_then_else
+	  (ge (match_operand:SI 0 "general_operand" "+d*am")
+	      (const_int 1))
+	  (label_ref (match_operand 1 "" ""))
+	  (pc)))
+   (set (match_dup 0)
+	(plus:SI (match_dup 0)
+		 (const_int -1)))]
+  "find_reg_note (insn, REG_NONNEG, 0)"
+  "@dots{}")
+@end group
+@end smallexample
+
+The other two special looping patterns, @samp{doloop_begin} and
+@samp{doloop_end}, are emitted by the loop optimizer for certain
+well-behaved loops with a finite number of loop iterations using
+information collected during strength reduction.
+
+The @samp{doloop_end} pattern describes the actual looping instruction
+(or the implicit looping operation) and the @samp{doloop_begin} pattern
+is an optional companion pattern that can be used for initialization
+needed for some low-overhead looping instructions.
+
+Note that some machines require the actual looping instruction to be
+emitted at the top of the loop (e.g., the TMS320C3x/C4x DSPs).  Emitting
+the true RTL for a looping instruction at the top of the loop can cause
+problems with flow analysis.  So instead, a dummy @code{doloop} insn is
+emitted at the end of the loop.  The machine dependent reorg pass checks
+for the presence of this @code{doloop} insn and then searches back to
+the top of the loop, where it inserts the true looping insn (provided
+there are no instructions in the loop which would cause problems).  Any
+additional labels can be emitted at this point.  In addition, if the
+desired special iteration counter register was not allocated, this
+machine dependent reorg pass could emit a traditional compare and jump
+instruction pair.
+
+The essential difference between the
+@samp{decrement_and_branch_until_zero} and the @samp{doloop_end}
+patterns is that the loop optimizer allocates an additional pseudo
+register for the latter as an iteration counter.  This pseudo register
+cannot be used within the loop (i.e., general induction variables cannot
+be derived from it), however, in many cases the loop induction variable
+may become redundant and removed by the flow pass.
+
+
+@node Insn Canonicalizations
+@section Canonicalization of Instructions
+@cindex canonicalization of instructions
+@cindex insn canonicalization
+
+There are often cases where multiple RTL expressions could represent an
+operation performed by a single machine instruction.  This situation is
+most commonly encountered with logical, branch, and multiply-accumulate
+instructions.  In such cases, the compiler attempts to convert these
+multiple RTL expressions into a single canonical form to reduce the
+number of insn patterns required.
+
+In addition to algebraic simplifications, following canonicalizations
+are performed:
+
+@itemize @bullet
+@item
+For commutative and comparison operators, a constant is always made the
+second operand.  If a machine only supports a constant as the second
+operand, only patterns that match a constant in the second operand need
+be supplied.
+
+@cindex @code{neg}, canonicalization of
+@cindex @code{not}, canonicalization of
+@cindex @code{mult}, canonicalization of
+@cindex @code{plus}, canonicalization of
+@cindex @code{minus}, canonicalization of
+For these operators, if only one operand is a @code{neg}, @code{not},
+@code{mult}, @code{plus}, or @code{minus} expression, it will be the
+first operand.
+
+@cindex @code{compare}, canonicalization of
+@item
+For the @code{compare} operator, a constant is always the second operand
+on machines where @code{cc0} is used (@pxref{Jump Patterns}).  On other
+machines, there are rare cases where the compiler might want to construct
+a @code{compare} with a constant as the first operand.  However, these
+cases are not common enough for it to be worthwhile to provide a pattern
+matching a constant as the first operand unless the machine actually has
+such an instruction.
+
+An operand of @code{neg}, @code{not}, @code{mult}, @code{plus}, or
+@code{minus} is made the first operand under the same conditions as
+above.
+
+@item
+@code{(minus @var{x} (const_int @var{n}))} is converted to
+@code{(plus @var{x} (const_int @var{-n}))}.
+
+@item
+Within address computations (i.e., inside @code{mem}), a left shift is
+converted into the appropriate multiplication by a power of two.
+
+@cindex @code{ior}, canonicalization of
+@cindex @code{and}, canonicalization of
+@cindex De Morgan's law
+@item
+De`Morgan's Law is used to move bitwise negation inside a bitwise
+logical-and or logical-or operation.  If this results in only one
+operand being a @code{not} expression, it will be the first one.
+
+A machine that has an instruction that performs a bitwise logical-and of one
+operand with the bitwise negation of the other should specify the pattern
+for that instruction as
+
+@example
+(define_insn ""
+  [(set (match_operand:@var{m} 0 @dots{})
+        (and:@var{m} (not:@var{m} (match_operand:@var{m} 1 @dots{}))
+                     (match_operand:@var{m} 2 @dots{})))]
+  "@dots{}"
+  "@dots{}")
+@end example
+
+@noindent
+Similarly, a pattern for a ``NAND'' instruction should be written
+
+@example
+(define_insn ""
+  [(set (match_operand:@var{m} 0 @dots{})
+        (ior:@var{m} (not:@var{m} (match_operand:@var{m} 1 @dots{}))
+                     (not:@var{m} (match_operand:@var{m} 2 @dots{}))))]
+  "@dots{}"
+  "@dots{}")
+@end example
+
+In both cases, it is not necessary to include patterns for the many
+logically equivalent RTL expressions.
+
+@cindex @code{xor}, canonicalization of
+@item
+The only possible RTL expressions involving both bitwise exclusive-or
+and bitwise negation are @code{(xor:@var{m} @var{x} @var{y})}
+and @code{(not:@var{m} (xor:@var{m} @var{x} @var{y}))}.
+
+@item
+The sum of three items, one of which is a constant, will only appear in
+the form
+
+@example
+(plus:@var{m} (plus:@var{m} @var{x} @var{y}) @var{constant})
+@end example
+
+@item
+On machines that do not use @code{cc0},
+@code{(compare @var{x} (const_int 0))} will be converted to
+@var{x}.
+
+@cindex @code{zero_extract}, canonicalization of
+@cindex @code{sign_extract}, canonicalization of
+@item
+Equality comparisons of a group of bits (usually a single bit) with zero
+will be written using @code{zero_extract} rather than the equivalent
+@code{and} or @code{sign_extract} operations.
+
+@end itemize
+
+@node Expander Definitions
+@section Defining RTL Sequences for Code Generation
+@cindex expander definitions
+@cindex code generation RTL sequences
+@cindex defining RTL sequences for code generation
+
+On some target machines, some standard pattern names for RTL generation
+cannot be handled with single insn, but a sequence of RTL insns can
+represent them.  For these target machines, you can write a
+@code{define_expand} to specify how to generate the sequence of RTL@.
+
+@findex define_expand
+A @code{define_expand} is an RTL expression that looks almost like a
+@code{define_insn}; but, unlike the latter, a @code{define_expand} is used
+only for RTL generation and it can produce more than one RTL insn.
+
+A @code{define_expand} RTX has four operands:
+
+@itemize @bullet
+@item
+The name.  Each @code{define_expand} must have a name, since the only
+use for it is to refer to it by name.
+
+@item
+The RTL template.  This is a vector of RTL expressions representing
+a sequence of separate instructions.  Unlike @code{define_insn}, there
+is no implicit surrounding @code{PARALLEL}.
+
+@item
+The condition, a string containing a C expression.  This expression is
+used to express how the availability of this pattern depends on
+subclasses of target machine, selected by command-line options when GCC
+is run.  This is just like the condition of a @code{define_insn} that
+has a standard name.  Therefore, the condition (if present) may not
+depend on the data in the insn being matched, but only the
+target-machine-type flags.  The compiler needs to test these conditions
+during initialization in order to learn exactly which named instructions
+are available in a particular run.
+
+@item
+The preparation statements, a string containing zero or more C
+statements which are to be executed before RTL code is generated from
+the RTL template.
+
+Usually these statements prepare temporary registers for use as
+internal operands in the RTL template, but they can also generate RTL
+insns directly by calling routines such as @code{emit_insn}, etc.
+Any such insns precede the ones that come from the RTL template.
+@end itemize
+
+Every RTL insn emitted by a @code{define_expand} must match some
+@code{define_insn} in the machine description.  Otherwise, the compiler
+will crash when trying to generate code for the insn or trying to optimize
+it.
+
+The RTL template, in addition to controlling generation of RTL insns,
+also describes the operands that need to be specified when this pattern
+is used.  In particular, it gives a predicate for each operand.
+
+A true operand, which needs to be specified in order to generate RTL from
+the pattern, should be described with a @code{match_operand} in its first
+occurrence in the RTL template.  This enters information on the operand's
+predicate into the tables that record such things.  GCC uses the
+information to preload the operand into a register if that is required for
+valid RTL code.  If the operand is referred to more than once, subsequent
+references should use @code{match_dup}.
+
+The RTL template may also refer to internal ``operands'' which are
+temporary registers or labels used only within the sequence made by the
+@code{define_expand}.  Internal operands are substituted into the RTL
+template with @code{match_dup}, never with @code{match_operand}.  The
+values of the internal operands are not passed in as arguments by the
+compiler when it requests use of this pattern.  Instead, they are computed
+within the pattern, in the preparation statements.  These statements
+compute the values and store them into the appropriate elements of
+@code{operands} so that @code{match_dup} can find them.
+
+There are two special macros defined for use in the preparation statements:
+@code{DONE} and @code{FAIL}.  Use them with a following semicolon,
+as a statement.
+
+@table @code
+
+@findex DONE
+@item DONE
+Use the @code{DONE} macro to end RTL generation for the pattern.  The
+only RTL insns resulting from the pattern on this occasion will be
+those already emitted by explicit calls to @code{emit_insn} within the
+preparation statements; the RTL template will not be generated.
+
+@findex FAIL
+@item FAIL
+Make the pattern fail on this occasion.  When a pattern fails, it means
+that the pattern was not truly available.  The calling routines in the
+compiler will try other strategies for code generation using other patterns.
+
+Failure is currently supported only for binary (addition, multiplication,
+shifting, etc.) and bit-field (@code{extv}, @code{extzv}, and @code{insv})
+operations.
+@end table
+
+If the preparation falls through (invokes neither @code{DONE} nor
+@code{FAIL}), then the @code{define_expand} acts like a
+@code{define_insn} in that the RTL template is used to generate the
+insn.
+
+The RTL template is not used for matching, only for generating the
+initial insn list.  If the preparation statement always invokes
+@code{DONE} or @code{FAIL}, the RTL template may be reduced to a simple
+list of operands, such as this example:
+
+@smallexample
+@group
+(define_expand "addsi3"
+  [(match_operand:SI 0 "register_operand" "")
+   (match_operand:SI 1 "register_operand" "")
+   (match_operand:SI 2 "register_operand" "")]
+@end group
+@group
+  ""
+  "
+@{
+  handle_add (operands[0], operands[1], operands[2]);
+  DONE;
+@}")
+@end group
+@end smallexample
+
+Here is an example, the definition of left-shift for the SPUR chip:
+
+@smallexample
+@group
+(define_expand "ashlsi3"
+  [(set (match_operand:SI 0 "register_operand" "")
+        (ashift:SI
+@end group
+@group
+          (match_operand:SI 1 "register_operand" "")
+          (match_operand:SI 2 "nonmemory_operand" "")))]
+  ""
+  "
+@end group
+@end smallexample
+
+@smallexample
+@group
+@{
+  if (GET_CODE (operands[2]) != CONST_INT
+      || (unsigned) INTVAL (operands[2]) > 3)
+    FAIL;
+@}")
+@end group
+@end smallexample
+
+@noindent
+This example uses @code{define_expand} so that it can generate an RTL insn
+for shifting when the shift-count is in the supported range of 0 to 3 but
+fail in other cases where machine insns aren't available.  When it fails,
+the compiler tries another strategy using different patterns (such as, a
+library call).
+
+If the compiler were able to handle nontrivial condition-strings in
+patterns with names, then it would be possible to use a
+@code{define_insn} in that case.  Here is another case (zero-extension
+on the 68000) which makes more use of the power of @code{define_expand}:
+
+@smallexample
+(define_expand "zero_extendhisi2"
+  [(set (match_operand:SI 0 "general_operand" "")
+        (const_int 0))
+   (set (strict_low_part
+          (subreg:HI
+            (match_dup 0)
+            0))
+        (match_operand:HI 1 "general_operand" ""))]
+  ""
+  "operands[1] = make_safe_from (operands[1], operands[0]);")
+@end smallexample
+
+@noindent
+@findex make_safe_from
+Here two RTL insns are generated, one to clear the entire output operand
+and the other to copy the input operand into its low half.  This sequence
+is incorrect if the input operand refers to [the old value of] the output
+operand, so the preparation statement makes sure this isn't so.  The
+function @code{make_safe_from} copies the @code{operands[1]} into a
+temporary register if it refers to @code{operands[0]}.  It does this
+by emitting another RTL insn.
+
+Finally, a third example shows the use of an internal operand.
+Zero-extension on the SPUR chip is done by @code{and}-ing the result
+against a halfword mask.  But this mask cannot be represented by a
+@code{const_int} because the constant value is too large to be legitimate
+on this machine.  So it must be copied into a register with
+@code{force_reg} and then the register used in the @code{and}.
+
+@smallexample
+(define_expand "zero_extendhisi2"
+  [(set (match_operand:SI 0 "register_operand" "")
+        (and:SI (subreg:SI
+                  (match_operand:HI 1 "register_operand" "")
+                  0)
+                (match_dup 2)))]
+  ""
+  "operands[2]
+     = force_reg (SImode, GEN_INT (65535)); ")
+@end smallexample
+
+@strong{Note:} If the @code{define_expand} is used to serve a
+standard binary or unary arithmetic operation or a bit-field operation,
+then the last insn it generates must not be a @code{code_label},
+@code{barrier} or @code{note}.  It must be an @code{insn},
+@code{jump_insn} or @code{call_insn}.  If you don't need a real insn
+at the end, emit an insn to copy the result of the operation into
+itself.  Such an insn will generate no code, but it can avoid problems
+in the compiler.
+
+@node Insn Splitting
+@section Defining How to Split Instructions
+@cindex insn splitting
+@cindex instruction splitting
+@cindex splitting instructions
+
+There are two cases where you should specify how to split a pattern into
+multiple insns.  On machines that have instructions requiring delay
+slots (@pxref{Delay Slots}) or that have instructions whose output is
+not available for multiple cycles (@pxref{Function Units}), the compiler
+phases that optimize these cases need to be able to move insns into
+one-instruction delay slots.  However, some insns may generate more than one
+machine instruction.  These insns cannot be placed into a delay slot.
+
+Often you can rewrite the single insn as a list of individual insns,
+each corresponding to one machine instruction.  The disadvantage of
+doing so is that it will cause the compilation to be slower and require
+more space.  If the resulting insns are too complex, it may also
+suppress some optimizations.  The compiler splits the insn if there is a
+reason to believe that it might improve instruction or delay slot
+scheduling.
+
+The insn combiner phase also splits putative insns.  If three insns are
+merged into one insn with a complex expression that cannot be matched by
+some @code{define_insn} pattern, the combiner phase attempts to split
+the complex pattern into two insns that are recognized.  Usually it can
+break the complex pattern into two patterns by splitting out some
+subexpression.  However, in some other cases, such as performing an
+addition of a large constant in two insns on a RISC machine, the way to
+split the addition into two insns is machine-dependent.
+
+@findex define_split
+The @code{define_split} definition tells the compiler how to split a
+complex insn into several simpler insns.  It looks like this:
+
+@smallexample
+(define_split
+  [@var{insn-pattern}]
+  "@var{condition}"
+  [@var{new-insn-pattern-1}
+   @var{new-insn-pattern-2}
+   @dots{}]
+  "@var{preparation-statements}")
+@end smallexample
+
+@var{insn-pattern} is a pattern that needs to be split and
+@var{condition} is the final condition to be tested, as in a
+@code{define_insn}.  When an insn matching @var{insn-pattern} and
+satisfying @var{condition} is found, it is replaced in the insn list
+with the insns given by @var{new-insn-pattern-1},
+@var{new-insn-pattern-2}, etc.
+
+The @var{preparation-statements} are similar to those statements that
+are specified for @code{define_expand} (@pxref{Expander Definitions})
+and are executed before the new RTL is generated to prepare for the
+generated code or emit some insns whose pattern is not fixed.  Unlike
+those in @code{define_expand}, however, these statements must not
+generate any new pseudo-registers.  Once reload has completed, they also
+must not allocate any space in the stack frame.
+
+Patterns are matched against @var{insn-pattern} in two different
+circumstances.  If an insn needs to be split for delay slot scheduling
+or insn scheduling, the insn is already known to be valid, which means
+that it must have been matched by some @code{define_insn} and, if
+@code{reload_completed} is nonzero, is known to satisfy the constraints
+of that @code{define_insn}.  In that case, the new insn patterns must
+also be insns that are matched by some @code{define_insn} and, if
+@code{reload_completed} is nonzero, must also satisfy the constraints
+of those definitions.
+
+As an example of this usage of @code{define_split}, consider the following
+example from @file{a29k.md}, which splits a @code{sign_extend} from
+@code{HImode} to @code{SImode} into a pair of shift insns:
+
+@smallexample
+(define_split
+  [(set (match_operand:SI 0 "gen_reg_operand" "")
+        (sign_extend:SI (match_operand:HI 1 "gen_reg_operand" "")))]
+  ""
+  [(set (match_dup 0)
+        (ashift:SI (match_dup 1)
+                   (const_int 16)))
+   (set (match_dup 0)
+        (ashiftrt:SI (match_dup 0)
+                     (const_int 16)))]
+  "
+@{ operands[1] = gen_lowpart (SImode, operands[1]); @}")
+@end smallexample
+
+When the combiner phase tries to split an insn pattern, it is always the
+case that the pattern is @emph{not} matched by any @code{define_insn}.
+The combiner pass first tries to split a single @code{set} expression
+and then the same @code{set} expression inside a @code{parallel}, but
+followed by a @code{clobber} of a pseudo-reg to use as a scratch
+register.  In these cases, the combiner expects exactly two new insn
+patterns to be generated.  It will verify that these patterns match some
+@code{define_insn} definitions, so you need not do this test in the
+@code{define_split} (of course, there is no point in writing a
+@code{define_split} that will never produce insns that match).
+
+Here is an example of this use of @code{define_split}, taken from
+@file{rs6000.md}:
+
+@smallexample
+(define_split
+  [(set (match_operand:SI 0 "gen_reg_operand" "")
+        (plus:SI (match_operand:SI 1 "gen_reg_operand" "")
+                 (match_operand:SI 2 "non_add_cint_operand" "")))]
+  ""
+  [(set (match_dup 0) (plus:SI (match_dup 1) (match_dup 3)))
+   (set (match_dup 0) (plus:SI (match_dup 0) (match_dup 4)))]
+"
+@{
+  int low = INTVAL (operands[2]) & 0xffff;
+  int high = (unsigned) INTVAL (operands[2]) >> 16;
+
+  if (low & 0x8000)
+    high++, low |= 0xffff0000;
+
+  operands[3] = GEN_INT (high << 16);
+  operands[4] = GEN_INT (low);
+@}")
+@end smallexample
+
+Here the predicate @code{non_add_cint_operand} matches any
+@code{const_int} that is @emph{not} a valid operand of a single add
+insn.  The add with the smaller displacement is written so that it
+can be substituted into the address of a subsequent operation.
+
+An example that uses a scratch register, from the same file, generates
+an equality comparison of a register and a large constant:
+
+@smallexample
+(define_split
+  [(set (match_operand:CC 0 "cc_reg_operand" "")
+        (compare:CC (match_operand:SI 1 "gen_reg_operand" "")
+                    (match_operand:SI 2 "non_short_cint_operand" "")))
+   (clobber (match_operand:SI 3 "gen_reg_operand" ""))]
+  "find_single_use (operands[0], insn, 0)
+   && (GET_CODE (*find_single_use (operands[0], insn, 0)) == EQ
+       || GET_CODE (*find_single_use (operands[0], insn, 0)) == NE)"
+  [(set (match_dup 3) (xor:SI (match_dup 1) (match_dup 4)))
+   (set (match_dup 0) (compare:CC (match_dup 3) (match_dup 5)))]
+  "
+@{
+  /* Get the constant we are comparing against, C, and see what it
+     looks like sign-extended to 16 bits.  Then see what constant
+     could be XOR'ed with C to get the sign-extended value.  */
+
+  int c = INTVAL (operands[2]);
+  int sextc = (c << 16) >> 16;
+  int xorv = c ^ sextc;
+
+  operands[4] = GEN_INT (xorv);
+  operands[5] = GEN_INT (sextc);
+@}")
+@end smallexample
+
+To avoid confusion, don't write a single @code{define_split} that
+accepts some insns that match some @code{define_insn} as well as some
+insns that don't.  Instead, write two separate @code{define_split}
+definitions, one for the insns that are valid and one for the insns that
+are not valid.
+
+The splitter is allowed to split jump instructions into sequence of
+jumps or create new jumps in while splitting non-jump instructions.  As
+the central flowgraph and branch prediction information needs to be updated,
+several restriction apply. 
+
+Splitting of jump instruction into sequence that over by another jump
+instruction is always valid, as compiler expect identical behavior of new
+jump.  When new sequence contains multiple jump instructions or new labels,
+more assistance is needed.  Splitter is required to create only unconditional
+jumps, or simple conditional jump instructions.  Additionally it must attach a
+@code{REG_BR_PROB} note to each conditional jump. An global variable
+@code{split_branch_probability} hold the probability of original branch in case
+it was an simple conditional jump, @minus{}1 otherwise.  To simplify
+recomputing of edge frequencies, new sequence is required to have only
+forward jumps to the newly created labels.
+
+@findex define_insn_and_split
+For the common case where the pattern of a define_split exactly matches the
+pattern of a define_insn, use @code{define_insn_and_split}.  It looks like
+this:
+
+@smallexample
+(define_insn_and_split
+  [@var{insn-pattern}]
+  "@var{condition}"
+  "@var{output-template}"
+  "@var{split-condition}"
+  [@var{new-insn-pattern-1}
+   @var{new-insn-pattern-2}
+   @dots{}]
+  "@var{preparation-statements}"
+  [@var{insn-attributes}])
+
+@end smallexample
+
+@var{insn-pattern}, @var{condition}, @var{output-template}, and
+@var{insn-attributes} are used as in @code{define_insn}.  The
+@var{new-insn-pattern} vector and the @var{preparation-statements} are used as
+in a @code{define_split}.  The @var{split-condition} is also used as in
+@code{define_split}, with the additional behavior that if the condition starts
+with @samp{&&}, the condition used for the split will be the constructed as a
+logical ``and'' of the split condition with the insn condition.  For example,
+from i386.md:
+
+@smallexample
+(define_insn_and_split "zero_extendhisi2_and"
+  [(set (match_operand:SI 0 "register_operand" "=r")
+     (zero_extend:SI (match_operand:HI 1 "register_operand" "0")))
+   (clobber (reg:CC 17))]
+  "TARGET_ZERO_EXTEND_WITH_AND && !optimize_size"
+  "#"
+  "&& reload_completed"
+  [(parallel [(set (match_dup 0) 
+                   (and:SI (match_dup 0) (const_int 65535)))
+	      (clobber (reg:CC 17))])]
+  ""
+  [(set_attr "type" "alu1")])
+
+@end smallexample
+
+In this case, the actual split condition will be
+@samp{TARGET_ZERO_EXTEND_WITH_AND && !optimize_size && reload_completed}.
+
+The @code{define_insn_and_split} construction provides exactly the same
+functionality as two separate @code{define_insn} and @code{define_split}
+patterns.  It exists for compactness, and as a maintenance tool to prevent
+having to ensure the two patterns' templates match.
+
+@node Including Patterns
+@section Including Patterns in Machine Descriptions.
+@cindex insn includes
+
+@findex include
+The @code{include} pattern tells the compiler tools where to
+look for patterns that are in files other than in the file
+@file{.md}. This is used only at build time and there is no preprocessing allowed.
+
+It looks like:
+
+@smallexample
+
+(include
+  @var{pathname})
+@end smallexample
+
+For example:
+
+@smallexample
+
+(include "filestuff") 
+
+@end smallexample
+
+Where @var{pathname} is a string that specifies the the location of the file,
+specifies the include file to be in @file{gcc/config/target/filestuff}. The
+directory @file{gcc/config/target} is regarded as the default directory.
+
+
+Machine descriptions may be split up into smaller more manageable subsections 
+and placed into subdirectories. 
+
+By specifying:
+
+@smallexample
+
+(include "BOGUS/filestuff") 
+
+@end smallexample
+
+the include file is specified to be in @file{gcc/config/@var{target}/BOGUS/filestuff}.
+
+Specifying an absolute path for the include file such as;
+@smallexample
+
+(include "/u2/BOGUS/filestuff") 
+
+@end smallexample
+is permitted but is not encouraged. 
+
+@subsection RTL Generation Tool Options for Directory Search
+@cindex directory options .md
+@cindex options, directory search
+@cindex search options
+
+The @option{-I@var{dir}} option specifies directories to search for machine descriptions.
+For example:
+
+@smallexample
+
+genrecog -I/p1/abc/proc1 -I/p2/abcd/pro2 target.md
+
+@end smallexample
+
+
+Add the directory @var{dir} to the head of the list of directories to be
+searched for header files.  This can be used to override a system machine definition
+file, substituting your own version, since these directories are
+searched before the default machine description file directories.  If you use more than
+one @option{-I} option, the directories are scanned in left-to-right
+order; the standard default directory come after.
+
+
+@node Peephole Definitions
+@section Machine-Specific Peephole Optimizers
+@cindex peephole optimizer definitions
+@cindex defining peephole optimizers
+
+In addition to instruction patterns the @file{md} file may contain
+definitions of machine-specific peephole optimizations.
+
+The combiner does not notice certain peephole optimizations when the data
+flow in the program does not suggest that it should try them.  For example,
+sometimes two consecutive insns related in purpose can be combined even
+though the second one does not appear to use a register computed in the
+first one.  A machine-specific peephole optimizer can detect such
+opportunities.
+
+There are two forms of peephole definitions that may be used.  The
+original @code{define_peephole} is run at assembly output time to
+match insns and substitute assembly text.  Use of @code{define_peephole}
+is deprecated.
+
+A newer @code{define_peephole2} matches insns and substitutes new
+insns.  The @code{peephole2} pass is run after register allocation
+but before scheduling, which may result in much better code for
+targets that do scheduling.
+
+@menu
+* define_peephole::     RTL to Text Peephole Optimizers
+* define_peephole2::    RTL to RTL Peephole Optimizers
+@end menu
+
+@node define_peephole
+@subsection RTL to Text Peephole Optimizers
+@findex define_peephole
+
+@need 1000
+A definition looks like this:
+
+@smallexample
+(define_peephole
+  [@var{insn-pattern-1}
+   @var{insn-pattern-2}
+   @dots{}]
+  "@var{condition}"
+  "@var{template}"
+  "@var{optional-insn-attributes}")
+@end smallexample
+
+@noindent
+The last string operand may be omitted if you are not using any
+machine-specific information in this machine description.  If present,
+it must obey the same rules as in a @code{define_insn}.
+
+In this skeleton, @var{insn-pattern-1} and so on are patterns to match
+consecutive insns.  The optimization applies to a sequence of insns when
+@var{insn-pattern-1} matches the first one, @var{insn-pattern-2} matches
+the next, and so on.
+
+Each of the insns matched by a peephole must also match a
+@code{define_insn}.  Peepholes are checked only at the last stage just
+before code generation, and only optionally.  Therefore, any insn which
+would match a peephole but no @code{define_insn} will cause a crash in code
+generation in an unoptimized compilation, or at various optimization
+stages.
+
+The operands of the insns are matched with @code{match_operands},
+@code{match_operator}, and @code{match_dup}, as usual.  What is not
+usual is that the operand numbers apply to all the insn patterns in the
+definition.  So, you can check for identical operands in two insns by
+using @code{match_operand} in one insn and @code{match_dup} in the
+other.
+
+The operand constraints used in @code{match_operand} patterns do not have
+any direct effect on the applicability of the peephole, but they will
+be validated afterward, so make sure your constraints are general enough
+to apply whenever the peephole matches.  If the peephole matches
+but the constraints are not satisfied, the compiler will crash.
+
+It is safe to omit constraints in all the operands of the peephole; or
+you can write constraints which serve as a double-check on the criteria
+previously tested.
+
+Once a sequence of insns matches the patterns, the @var{condition} is
+checked.  This is a C expression which makes the final decision whether to
+perform the optimization (we do so if the expression is nonzero).  If
+@var{condition} is omitted (in other words, the string is empty) then the
+optimization is applied to every sequence of insns that matches the
+patterns.
+
+The defined peephole optimizations are applied after register allocation
+is complete.  Therefore, the peephole definition can check which
+operands have ended up in which kinds of registers, just by looking at
+the operands.
+
+@findex prev_active_insn
+The way to refer to the operands in @var{condition} is to write
+@code{operands[@var{i}]} for operand number @var{i} (as matched by
+@code{(match_operand @var{i} @dots{})}).  Use the variable @code{insn}
+to refer to the last of the insns being matched; use
+@code{prev_active_insn} to find the preceding insns.
+
+@findex dead_or_set_p
+When optimizing computations with intermediate results, you can use
+@var{condition} to match only when the intermediate results are not used
+elsewhere.  Use the C expression @code{dead_or_set_p (@var{insn},
+@var{op})}, where @var{insn} is the insn in which you expect the value
+to be used for the last time (from the value of @code{insn}, together
+with use of @code{prev_nonnote_insn}), and @var{op} is the intermediate
+value (from @code{operands[@var{i}]}).
+
+Applying the optimization means replacing the sequence of insns with one
+new insn.  The @var{template} controls ultimate output of assembler code
+for this combined insn.  It works exactly like the template of a
+@code{define_insn}.  Operand numbers in this template are the same ones
+used in matching the original sequence of insns.
+
+The result of a defined peephole optimizer does not need to match any of
+the insn patterns in the machine description; it does not even have an
+opportunity to match them.  The peephole optimizer definition itself serves
+as the insn pattern to control how the insn is output.
+
+Defined peephole optimizers are run as assembler code is being output,
+so the insns they produce are never combined or rearranged in any way.
+
+Here is an example, taken from the 68000 machine description:
+
+@smallexample
+(define_peephole
+  [(set (reg:SI 15) (plus:SI (reg:SI 15) (const_int 4)))
+   (set (match_operand:DF 0 "register_operand" "=f")
+        (match_operand:DF 1 "register_operand" "ad"))]
+  "FP_REG_P (operands[0]) && ! FP_REG_P (operands[1])"
+@{
+  rtx xoperands[2];
+  xoperands[1] = gen_rtx (REG, SImode, REGNO (operands[1]) + 1);
+#ifdef MOTOROLA
+  output_asm_insn ("move.l %1,(sp)", xoperands);
+  output_asm_insn ("move.l %1,-(sp)", operands);
+  return "fmove.d (sp)+,%0";
+#else
+  output_asm_insn ("movel %1,sp@@", xoperands);
+  output_asm_insn ("movel %1,sp@@-", operands);
+  return "fmoved sp@@+,%0";
+#endif
+@})
+@end smallexample
+
+@need 1000
+The effect of this optimization is to change
+
+@smallexample
+@group
+jbsr _foobar
+addql #4,sp
+movel d1,sp@@-
+movel d0,sp@@-
+fmoved sp@@+,fp0
+@end group
+@end smallexample
+
+@noindent
+into
+
+@smallexample
+@group
+jbsr _foobar
+movel d1,sp@@
+movel d0,sp@@-
+fmoved sp@@+,fp0
+@end group
+@end smallexample
+
+@ignore
+@findex CC_REVERSED
+If a peephole matches a sequence including one or more jump insns, you must
+take account of the flags such as @code{CC_REVERSED} which specify that the
+condition codes are represented in an unusual manner.  The compiler
+automatically alters any ordinary conditional jumps which occur in such
+situations, but the compiler cannot alter jumps which have been replaced by
+peephole optimizations.  So it is up to you to alter the assembler code
+that the peephole produces.  Supply C code to write the assembler output,
+and in this C code check the condition code status flags and change the
+assembler code as appropriate.
+@end ignore
+
+@var{insn-pattern-1} and so on look @emph{almost} like the second
+operand of @code{define_insn}.  There is one important difference: the
+second operand of @code{define_insn} consists of one or more RTX's
+enclosed in square brackets.  Usually, there is only one: then the same
+action can be written as an element of a @code{define_peephole}.  But
+when there are multiple actions in a @code{define_insn}, they are
+implicitly enclosed in a @code{parallel}.  Then you must explicitly
+write the @code{parallel}, and the square brackets within it, in the
+@code{define_peephole}.  Thus, if an insn pattern looks like this,
+
+@smallexample
+(define_insn "divmodsi4"
+  [(set (match_operand:SI 0 "general_operand" "=d")
+        (div:SI (match_operand:SI 1 "general_operand" "0")
+                (match_operand:SI 2 "general_operand" "dmsK")))
+   (set (match_operand:SI 3 "general_operand" "=d")
+        (mod:SI (match_dup 1) (match_dup 2)))]
+  "TARGET_68020"
+  "divsl%.l %2,%3:%0")
+@end smallexample
+
+@noindent
+then the way to mention this insn in a peephole is as follows:
+
+@smallexample
+(define_peephole
+  [@dots{}
+   (parallel
+    [(set (match_operand:SI 0 "general_operand" "=d")
+          (div:SI (match_operand:SI 1 "general_operand" "0")
+                  (match_operand:SI 2 "general_operand" "dmsK")))
+     (set (match_operand:SI 3 "general_operand" "=d")
+          (mod:SI (match_dup 1) (match_dup 2)))])
+   @dots{}]
+  @dots{})
+@end smallexample
+
+@node define_peephole2
+@subsection RTL to RTL Peephole Optimizers
+@findex define_peephole2
+
+The @code{define_peephole2} definition tells the compiler how to
+substitute one sequence of instructions for another sequence,
+what additional scratch registers may be needed and what their
+lifetimes must be.
+
+@smallexample
+(define_peephole2
+  [@var{insn-pattern-1}
+   @var{insn-pattern-2}
+   @dots{}]
+  "@var{condition}"
+  [@var{new-insn-pattern-1}
+   @var{new-insn-pattern-2}
+   @dots{}]
+  "@var{preparation-statements}")
+@end smallexample
+
+The definition is almost identical to @code{define_split}
+(@pxref{Insn Splitting}) except that the pattern to match is not a
+single instruction, but a sequence of instructions.
+
+It is possible to request additional scratch registers for use in the
+output template.  If appropriate registers are not free, the pattern
+will simply not match.
+
+@findex match_scratch
+@findex match_dup
+Scratch registers are requested with a @code{match_scratch} pattern at
+the top level of the input pattern.  The allocated register (initially) will
+be dead at the point requested within the original sequence.  If the scratch
+is used at more than a single point, a @code{match_dup} pattern at the
+top level of the input pattern marks the last position in the input sequence
+at which the register must be available.
+
+Here is an example from the IA-32 machine description:
+
+@smallexample
+(define_peephole2
+  [(match_scratch:SI 2 "r")
+   (parallel [(set (match_operand:SI 0 "register_operand" "")
+                   (match_operator:SI 3 "arith_or_logical_operator"
+                     [(match_dup 0)
+                      (match_operand:SI 1 "memory_operand" "")]))
+              (clobber (reg:CC 17))])]
+  "! optimize_size && ! TARGET_READ_MODIFY"
+  [(set (match_dup 2) (match_dup 1))
+   (parallel [(set (match_dup 0)
+                   (match_op_dup 3 [(match_dup 0) (match_dup 2)]))
+              (clobber (reg:CC 17))])]
+  "")
+@end smallexample
+
+@noindent
+This pattern tries to split a load from its use in the hopes that we'll be
+able to schedule around the memory load latency.  It allocates a single
+@code{SImode} register of class @code{GENERAL_REGS} (@code{"r"}) that needs
+to be live only at the point just before the arithmetic.
+
+A real example requiring extended scratch lifetimes is harder to come by,
+so here's a silly made-up example:
+
+@smallexample
+(define_peephole2
+  [(match_scratch:SI 4 "r")
+   (set (match_operand:SI 0 "" "") (match_operand:SI 1 "" ""))
+   (set (match_operand:SI 2 "" "") (match_dup 1))
+   (match_dup 4)
+   (set (match_operand:SI 3 "" "") (match_dup 1))]
+  "/* @r{determine 1 does not overlap 0 and 2} */"
+  [(set (match_dup 4) (match_dup 1))
+   (set (match_dup 0) (match_dup 4))
+   (set (match_dup 2) (match_dup 4))]
+   (set (match_dup 3) (match_dup 4))]
+  "")
+@end smallexample
+
+@noindent
+If we had not added the @code{(match_dup 4)} in the middle of the input
+sequence, it might have been the case that the register we chose at the
+beginning of the sequence is killed by the first or second @code{set}.
+
+@node Insn Attributes
+@section Instruction Attributes
+@cindex insn attributes
+@cindex instruction attributes
+
+In addition to describing the instruction supported by the target machine,
+the @file{md} file also defines a group of @dfn{attributes} and a set of
+values for each.  Every generated insn is assigned a value for each attribute.
+One possible attribute would be the effect that the insn has on the machine's
+condition code.  This attribute can then be used by @code{NOTICE_UPDATE_CC}
+to track the condition codes.
+
+@menu
+* Defining Attributes:: Specifying attributes and their values.
+* Expressions::         Valid expressions for attribute values.
+* Tagging Insns::       Assigning attribute values to insns.
+* Attr Example::        An example of assigning attributes.
+* Insn Lengths::        Computing the length of insns.
+* Constant Attributes:: Defining attributes that are constant.
+* Delay Slots::         Defining delay slots required for a machine.
+* Function Units::      Specifying information for insn scheduling.
+@end menu
+
+@node Defining Attributes
+@subsection Defining Attributes and their Values
+@cindex defining attributes and their values
+@cindex attributes, defining
+
+@findex define_attr
+The @code{define_attr} expression is used to define each attribute required
+by the target machine.  It looks like:
+
+@smallexample
+(define_attr @var{name} @var{list-of-values} @var{default})
+@end smallexample
+
+@var{name} is a string specifying the name of the attribute being defined.
+
+@var{list-of-values} is either a string that specifies a comma-separated
+list of values that can be assigned to the attribute, or a null string to
+indicate that the attribute takes numeric values.
+
+@var{default} is an attribute expression that gives the value of this
+attribute for insns that match patterns whose definition does not include
+an explicit value for this attribute.  @xref{Attr Example}, for more
+information on the handling of defaults.  @xref{Constant Attributes},
+for information on attributes that do not depend on any particular insn.
+
+@findex insn-attr.h
+For each defined attribute, a number of definitions are written to the
+@file{insn-attr.h} file.  For cases where an explicit set of values is
+specified for an attribute, the following are defined:
+
+@itemize @bullet
+@item
+A @samp{#define} is written for the symbol @samp{HAVE_ATTR_@var{name}}.
+
+@item
+An enumeral class is defined for @samp{attr_@var{name}} with
+elements of the form @samp{@var{upper-name}_@var{upper-value}} where
+the attribute name and value are first converted to upper case.
+
+@item
+A function @samp{get_attr_@var{name}} is defined that is passed an insn and
+returns the attribute value for that insn.
+@end itemize
+
+For example, if the following is present in the @file{md} file:
+
+@smallexample
+(define_attr "type" "branch,fp,load,store,arith" @dots{})
+@end smallexample
+
+@noindent
+the following lines will be written to the file @file{insn-attr.h}.
+
+@smallexample
+#define HAVE_ATTR_type
+enum attr_type @{TYPE_BRANCH, TYPE_FP, TYPE_LOAD,
+                 TYPE_STORE, TYPE_ARITH@};
+extern enum attr_type get_attr_type ();
+@end smallexample
+
+If the attribute takes numeric values, no @code{enum} type will be
+defined and the function to obtain the attribute's value will return
+@code{int}.
+
+@node Expressions
+@subsection Attribute Expressions
+@cindex attribute expressions
+
+RTL expressions used to define attributes use the codes described above
+plus a few specific to attribute definitions, to be discussed below.
+Attribute value expressions must have one of the following forms:
+
+@table @code
+@cindex @code{const_int} and attributes
+@item (const_int @var{i})
+The integer @var{i} specifies the value of a numeric attribute.  @var{i}
+must be non-negative.
+
+The value of a numeric attribute can be specified either with a
+@code{const_int}, or as an integer represented as a string in
+@code{const_string}, @code{eq_attr} (see below), @code{attr},
+@code{symbol_ref}, simple arithmetic expressions, and @code{set_attr}
+overrides on specific instructions (@pxref{Tagging Insns}).
+
+@cindex @code{const_string} and attributes
+@item (const_string @var{value})
+The string @var{value} specifies a constant attribute value.
+If @var{value} is specified as @samp{"*"}, it means that the default value of
+the attribute is to be used for the insn containing this expression.
+@samp{"*"} obviously cannot be used in the @var{default} expression
+of a @code{define_attr}.
+
+If the attribute whose value is being specified is numeric, @var{value}
+must be a string containing a non-negative integer (normally
+@code{const_int} would be used in this case).  Otherwise, it must
+contain one of the valid values for the attribute.
+
+@cindex @code{if_then_else} and attributes
+@item (if_then_else @var{test} @var{true-value} @var{false-value})
+@var{test} specifies an attribute test, whose format is defined below.
+The value of this expression is @var{true-value} if @var{test} is true,
+otherwise it is @var{false-value}.
+
+@cindex @code{cond} and attributes
+@item (cond [@var{test1} @var{value1} @dots{}] @var{default})
+The first operand of this expression is a vector containing an even
+number of expressions and consisting of pairs of @var{test} and @var{value}
+expressions.  The value of the @code{cond} expression is that of the
+@var{value} corresponding to the first true @var{test} expression.  If
+none of the @var{test} expressions are true, the value of the @code{cond}
+expression is that of the @var{default} expression.
+@end table
+
+@var{test} expressions can have one of the following forms:
+
+@table @code
+@cindex @code{const_int} and attribute tests
+@item (const_int @var{i})
+This test is true if @var{i} is nonzero and false otherwise.
+
+@cindex @code{not} and attributes
+@cindex @code{ior} and attributes
+@cindex @code{and} and attributes
+@item (not @var{test})
+@itemx (ior @var{test1} @var{test2})
+@itemx (and @var{test1} @var{test2})
+These tests are true if the indicated logical function is true.
+
+@cindex @code{match_operand} and attributes
+@item (match_operand:@var{m} @var{n} @var{pred} @var{constraints})
+This test is true if operand @var{n} of the insn whose attribute value
+is being determined has mode @var{m} (this part of the test is ignored
+if @var{m} is @code{VOIDmode}) and the function specified by the string
+@var{pred} returns a nonzero value when passed operand @var{n} and mode
+@var{m} (this part of the test is ignored if @var{pred} is the null
+string).
+
+The @var{constraints} operand is ignored and should be the null string.
+
+@cindex @code{le} and attributes
+@cindex @code{leu} and attributes
+@cindex @code{lt} and attributes
+@cindex @code{gt} and attributes
+@cindex @code{gtu} and attributes
+@cindex @code{ge} and attributes
+@cindex @code{geu} and attributes
+@cindex @code{ne} and attributes
+@cindex @code{eq} and attributes
+@cindex @code{plus} and attributes
+@cindex @code{minus} and attributes
+@cindex @code{mult} and attributes
+@cindex @code{div} and attributes
+@cindex @code{mod} and attributes
+@cindex @code{abs} and attributes
+@cindex @code{neg} and attributes
+@cindex @code{ashift} and attributes
+@cindex @code{lshiftrt} and attributes
+@cindex @code{ashiftrt} and attributes
+@item (le @var{arith1} @var{arith2})
+@itemx (leu @var{arith1} @var{arith2})
+@itemx (lt @var{arith1} @var{arith2})
+@itemx (ltu @var{arith1} @var{arith2})
+@itemx (gt @var{arith1} @var{arith2})
+@itemx (gtu @var{arith1} @var{arith2})
+@itemx (ge @var{arith1} @var{arith2})
+@itemx (geu @var{arith1} @var{arith2})
+@itemx (ne @var{arith1} @var{arith2})
+@itemx (eq @var{arith1} @var{arith2})
+These tests are true if the indicated comparison of the two arithmetic
+expressions is true.  Arithmetic expressions are formed with
+@code{plus}, @code{minus}, @code{mult}, @code{div}, @code{mod},
+@code{abs}, @code{neg}, @code{and}, @code{ior}, @code{xor}, @code{not},
+@code{ashift}, @code{lshiftrt}, and @code{ashiftrt} expressions.
+
+@findex get_attr
+@code{const_int} and @code{symbol_ref} are always valid terms (@pxref{Insn
+Lengths},for additional forms).  @code{symbol_ref} is a string
+denoting a C expression that yields an @code{int} when evaluated by the
+@samp{get_attr_@dots{}} routine.  It should normally be a global
+variable.
+
+@findex eq_attr
+@item (eq_attr @var{name} @var{value})
+@var{name} is a string specifying the name of an attribute.
+
+@var{value} is a string that is either a valid value for attribute
+@var{name}, a comma-separated list of values, or @samp{!} followed by a
+value or list.  If @var{value} does not begin with a @samp{!}, this
+test is true if the value of the @var{name} attribute of the current
+insn is in the list specified by @var{value}.  If @var{value} begins
+with a @samp{!}, this test is true if the attribute's value is
+@emph{not} in the specified list.
+
+For example,
+
+@smallexample
+(eq_attr "type" "load,store")
+@end smallexample
+
+@noindent
+is equivalent to
+
+@smallexample
+(ior (eq_attr "type" "load") (eq_attr "type" "store"))
+@end smallexample
+
+If @var{name} specifies an attribute of @samp{alternative}, it refers to the
+value of the compiler variable @code{which_alternative}
+(@pxref{Output Statement}) and the values must be small integers.  For
+example,
+
+@smallexample
+(eq_attr "alternative" "2,3")
+@end smallexample
+
+@noindent
+is equivalent to
+
+@smallexample
+(ior (eq (symbol_ref "which_alternative") (const_int 2))
+     (eq (symbol_ref "which_alternative") (const_int 3)))
+@end smallexample
+
+Note that, for most attributes, an @code{eq_attr} test is simplified in cases
+where the value of the attribute being tested is known for all insns matching
+a particular pattern.  This is by far the most common case.
+
+@findex attr_flag
+@item (attr_flag @var{name})
+The value of an @code{attr_flag} expression is true if the flag
+specified by @var{name} is true for the @code{insn} currently being
+scheduled.
+
+@var{name} is a string specifying one of a fixed set of flags to test.
+Test the flags @code{forward} and @code{backward} to determine the
+direction of a conditional branch.  Test the flags @code{very_likely},
+@code{likely}, @code{very_unlikely}, and @code{unlikely} to determine
+if a conditional branch is expected to be taken.
+
+If the @code{very_likely} flag is true, then the @code{likely} flag is also
+true.  Likewise for the @code{very_unlikely} and @code{unlikely} flags.
+
+This example describes a conditional branch delay slot which
+can be nullified for forward branches that are taken (annul-true) or
+for backward branches which are not taken (annul-false).
+
+@smallexample
+(define_delay (eq_attr "type" "cbranch")
+  [(eq_attr "in_branch_delay" "true")
+   (and (eq_attr "in_branch_delay" "true")
+        (attr_flag "forward"))
+   (and (eq_attr "in_branch_delay" "true")
+        (attr_flag "backward"))])
+@end smallexample
+
+The @code{forward} and @code{backward} flags are false if the current
+@code{insn} being scheduled is not a conditional branch.
+
+The @code{very_likely} and @code{likely} flags are true if the
+@code{insn} being scheduled is not a conditional branch.
+The @code{very_unlikely} and @code{unlikely} flags are false if the
+@code{insn} being scheduled is not a conditional branch.
+
+@code{attr_flag} is only used during delay slot scheduling and has no
+meaning to other passes of the compiler.
+
+@findex attr
+@item (attr @var{name})
+The value of another attribute is returned.  This is most useful
+for numeric attributes, as @code{eq_attr} and @code{attr_flag}
+produce more efficient code for non-numeric attributes.
+@end table
+
+@node Tagging Insns
+@subsection Assigning Attribute Values to Insns
+@cindex tagging insns
+@cindex assigning attribute values to insns
+
+The value assigned to an attribute of an insn is primarily determined by
+which pattern is matched by that insn (or which @code{define_peephole}
+generated it).  Every @code{define_insn} and @code{define_peephole} can
+have an optional last argument to specify the values of attributes for
+matching insns.  The value of any attribute not specified in a particular
+insn is set to the default value for that attribute, as specified in its
+@code{define_attr}.  Extensive use of default values for attributes
+permits the specification of the values for only one or two attributes
+in the definition of most insn patterns, as seen in the example in the
+next section.
+
+The optional last argument of @code{define_insn} and
+@code{define_peephole} is a vector of expressions, each of which defines
+the value for a single attribute.  The most general way of assigning an
+attribute's value is to use a @code{set} expression whose first operand is an
+@code{attr} expression giving the name of the attribute being set.  The
+second operand of the @code{set} is an attribute expression
+(@pxref{Expressions}) giving the value of the attribute.
+
+When the attribute value depends on the @samp{alternative} attribute
+(i.e., which is the applicable alternative in the constraint of the
+insn), the @code{set_attr_alternative} expression can be used.  It
+allows the specification of a vector of attribute expressions, one for
+each alternative.
+
+@findex set_attr
+When the generality of arbitrary attribute expressions is not required,
+the simpler @code{set_attr} expression can be used, which allows
+specifying a string giving either a single attribute value or a list
+of attribute values, one for each alternative.
+
+The form of each of the above specifications is shown below.  In each case,
+@var{name} is a string specifying the attribute to be set.
+
+@table @code
+@item (set_attr @var{name} @var{value-string})
+@var{value-string} is either a string giving the desired attribute value,
+or a string containing a comma-separated list giving the values for
+succeeding alternatives.  The number of elements must match the number
+of alternatives in the constraint of the insn pattern.
+
+Note that it may be useful to specify @samp{*} for some alternative, in
+which case the attribute will assume its default value for insns matching
+that alternative.
+
+@findex set_attr_alternative
+@item (set_attr_alternative @var{name} [@var{value1} @var{value2} @dots{}])
+Depending on the alternative of the insn, the value will be one of the
+specified values.  This is a shorthand for using a @code{cond} with
+tests on the @samp{alternative} attribute.
+
+@findex attr
+@item (set (attr @var{name}) @var{value})
+The first operand of this @code{set} must be the special RTL expression
+@code{attr}, whose sole operand is a string giving the name of the
+attribute being set.  @var{value} is the value of the attribute.
+@end table
+
+The following shows three different ways of representing the same
+attribute value specification:
+
+@smallexample
+(set_attr "type" "load,store,arith")
+
+(set_attr_alternative "type"
+                      [(const_string "load") (const_string "store")
+                       (const_string "arith")])
+
+(set (attr "type")
+     (cond [(eq_attr "alternative" "1") (const_string "load")
+            (eq_attr "alternative" "2") (const_string "store")]
+           (const_string "arith")))
+@end smallexample
+
+@need 1000
+@findex define_asm_attributes
+The @code{define_asm_attributes} expression provides a mechanism to
+specify the attributes assigned to insns produced from an @code{asm}
+statement.  It has the form:
+
+@smallexample
+(define_asm_attributes [@var{attr-sets}])
+@end smallexample
+
+@noindent
+where @var{attr-sets} is specified the same as for both the
+@code{define_insn} and the @code{define_peephole} expressions.
+
+These values will typically be the ``worst case'' attribute values.  For
+example, they might indicate that the condition code will be clobbered.
+
+A specification for a @code{length} attribute is handled specially.  The
+way to compute the length of an @code{asm} insn is to multiply the
+length specified in the expression @code{define_asm_attributes} by the
+number of machine instructions specified in the @code{asm} statement,
+determined by counting the number of semicolons and newlines in the
+string.  Therefore, the value of the @code{length} attribute specified
+in a @code{define_asm_attributes} should be the maximum possible length
+of a single machine instruction.
+
+@node Attr Example
+@subsection Example of Attribute Specifications
+@cindex attribute specifications example
+@cindex attribute specifications
+
+The judicious use of defaulting is important in the efficient use of
+insn attributes.  Typically, insns are divided into @dfn{types} and an
+attribute, customarily called @code{type}, is used to represent this
+value.  This attribute is normally used only to define the default value
+for other attributes.  An example will clarify this usage.
+
+Assume we have a RISC machine with a condition code and in which only
+full-word operations are performed in registers.  Let us assume that we
+can divide all insns into loads, stores, (integer) arithmetic
+operations, floating point operations, and branches.
+
+Here we will concern ourselves with determining the effect of an insn on
+the condition code and will limit ourselves to the following possible
+effects:  The condition code can be set unpredictably (clobbered), not
+be changed, be set to agree with the results of the operation, or only
+changed if the item previously set into the condition code has been
+modified.
+
+Here is part of a sample @file{md} file for such a machine:
+
+@smallexample
+(define_attr "type" "load,store,arith,fp,branch" (const_string "arith"))
+
+(define_attr "cc" "clobber,unchanged,set,change0"
+             (cond [(eq_attr "type" "load")
+                        (const_string "change0")
+                    (eq_attr "type" "store,branch")
+                        (const_string "unchanged")
+                    (eq_attr "type" "arith")
+                        (if_then_else (match_operand:SI 0 "" "")
+                                      (const_string "set")
+                                      (const_string "clobber"))]
+                   (const_string "clobber")))
+
+(define_insn ""
+  [(set (match_operand:SI 0 "general_operand" "=r,r,m")
+        (match_operand:SI 1 "general_operand" "r,m,r"))]
+  ""
+  "@@
+   move %0,%1
+   load %0,%1
+   store %0,%1"
+  [(set_attr "type" "arith,load,store")])
+@end smallexample
+
+Note that we assume in the above example that arithmetic operations
+performed on quantities smaller than a machine word clobber the condition
+code since they will set the condition code to a value corresponding to the
+full-word result.
+
+@node Insn Lengths
+@subsection Computing the Length of an Insn
+@cindex insn lengths, computing
+@cindex computing the length of an insn
+
+For many machines, multiple types of branch instructions are provided, each
+for different length branch displacements.  In most cases, the assembler
+will choose the correct instruction to use.  However, when the assembler
+cannot do so, GCC can when a special attribute, the @samp{length}
+attribute, is defined.  This attribute must be defined to have numeric
+values by specifying a null string in its @code{define_attr}.
+
+In the case of the @samp{length} attribute, two additional forms of
+arithmetic terms are allowed in test expressions:
+
+@table @code
+@cindex @code{match_dup} and attributes
+@item (match_dup @var{n})
+This refers to the address of operand @var{n} of the current insn, which
+must be a @code{label_ref}.
+
+@cindex @code{pc} and attributes
+@item (pc)
+This refers to the address of the @emph{current} insn.  It might have
+been more consistent with other usage to make this the address of the
+@emph{next} insn but this would be confusing because the length of the
+current insn is to be computed.
+@end table
+
+@cindex @code{addr_vec}, length of
+@cindex @code{addr_diff_vec}, length of
+For normal insns, the length will be determined by value of the
+@samp{length} attribute.  In the case of @code{addr_vec} and
+@code{addr_diff_vec} insn patterns, the length is computed as
+the number of vectors multiplied by the size of each vector.
+
+Lengths are measured in addressable storage units (bytes).
+
+The following macros can be used to refine the length computation:
+
+@table @code
+@findex FIRST_INSN_ADDRESS
+@item FIRST_INSN_ADDRESS
+When the @code{length} insn attribute is used, this macro specifies the
+value to be assigned to the address of the first insn in a function.  If
+not specified, 0 is used.
+
+@findex ADJUST_INSN_LENGTH
+@item ADJUST_INSN_LENGTH (@var{insn}, @var{length})
+If defined, modifies the length assigned to instruction @var{insn} as a
+function of the context in which it is used.  @var{length} is an lvalue
+that contains the initially computed length of the insn and should be
+updated with the correct length of the insn.
+
+This macro will normally not be required.  A case in which it is
+required is the ROMP@.  On this machine, the size of an @code{addr_vec}
+insn must be increased by two to compensate for the fact that alignment
+may be required.
+@end table
+
+@findex get_attr_length
+The routine that returns @code{get_attr_length} (the value of the
+@code{length} attribute) can be used by the output routine to
+determine the form of the branch instruction to be written, as the
+example below illustrates.
+
+As an example of the specification of variable-length branches, consider
+the IBM 360.  If we adopt the convention that a register will be set to
+the starting address of a function, we can jump to labels within 4k of
+the start using a four-byte instruction.  Otherwise, we need a six-byte
+sequence to load the address from memory and then branch to it.
+
+On such a machine, a pattern for a branch instruction might be specified
+as follows:
+
+@smallexample
+(define_insn "jump"
+  [(set (pc)
+        (label_ref (match_operand 0 "" "")))]
+  ""
+@{
+   return (get_attr_length (insn) == 4
+           ? "b %l0" : "l r15,=a(%l0); br r15");
+@}
+  [(set (attr "length")
+        (if_then_else (lt (match_dup 0) (const_int 4096))
+                      (const_int 4)
+                      (const_int 6)))])
+@end smallexample
+
+@node Constant Attributes
+@subsection Constant Attributes
+@cindex constant attributes
+
+A special form of @code{define_attr}, where the expression for the
+default value is a @code{const} expression, indicates an attribute that
+is constant for a given run of the compiler.  Constant attributes may be
+used to specify which variety of processor is used.  For example,
+
+@smallexample
+(define_attr "cpu" "m88100,m88110,m88000"
+ (const
+  (cond [(symbol_ref "TARGET_88100") (const_string "m88100")
+         (symbol_ref "TARGET_88110") (const_string "m88110")]
+        (const_string "m88000"))))
+
+(define_attr "memory" "fast,slow"
+ (const
+  (if_then_else (symbol_ref "TARGET_FAST_MEM")
+                (const_string "fast")
+                (const_string "slow"))))
+@end smallexample
+
+The routine generated for constant attributes has no parameters as it
+does not depend on any particular insn.  RTL expressions used to define
+the value of a constant attribute may use the @code{symbol_ref} form,
+but may not use either the @code{match_operand} form or @code{eq_attr}
+forms involving insn attributes.
+
+@node Delay Slots
+@subsection Delay Slot Scheduling
+@cindex delay slots, defining
+
+The insn attribute mechanism can be used to specify the requirements for
+delay slots, if any, on a target machine.  An instruction is said to
+require a @dfn{delay slot} if some instructions that are physically
+after the instruction are executed as if they were located before it.
+Classic examples are branch and call instructions, which often execute
+the following instruction before the branch or call is performed.
+
+On some machines, conditional branch instructions can optionally
+@dfn{annul} instructions in the delay slot.  This means that the
+instruction will not be executed for certain branch outcomes.  Both
+instructions that annul if the branch is true and instructions that
+annul if the branch is false are supported.
+
+Delay slot scheduling differs from instruction scheduling in that
+determining whether an instruction needs a delay slot is dependent only
+on the type of instruction being generated, not on data flow between the
+instructions.  See the next section for a discussion of data-dependent
+instruction scheduling.
+
+@findex define_delay
+The requirement of an insn needing one or more delay slots is indicated
+via the @code{define_delay} expression.  It has the following form:
+
+@smallexample
+(define_delay @var{test}
+              [@var{delay-1} @var{annul-true-1} @var{annul-false-1}
+               @var{delay-2} @var{annul-true-2} @var{annul-false-2}
+               @dots{}])
+@end smallexample
+
+@var{test} is an attribute test that indicates whether this
+@code{define_delay} applies to a particular insn.  If so, the number of
+required delay slots is determined by the length of the vector specified
+as the second argument.  An insn placed in delay slot @var{n} must
+satisfy attribute test @var{delay-n}.  @var{annul-true-n} is an
+attribute test that specifies which insns may be annulled if the branch
+is true.  Similarly, @var{annul-false-n} specifies which insns in the
+delay slot may be annulled if the branch is false.  If annulling is not
+supported for that delay slot, @code{(nil)} should be coded.
+
+For example, in the common case where branch and call insns require
+a single delay slot, which may contain any insn other than a branch or
+call, the following would be placed in the @file{md} file:
+
+@smallexample
+(define_delay (eq_attr "type" "branch,call")
+              [(eq_attr "type" "!branch,call") (nil) (nil)])
+@end smallexample
+
+Multiple @code{define_delay} expressions may be specified.  In this
+case, each such expression specifies different delay slot requirements
+and there must be no insn for which tests in two @code{define_delay}
+expressions are both true.
+
+For example, if we have a machine that requires one delay slot for branches
+but two for calls,  no delay slot can contain a branch or call insn,
+and any valid insn in the delay slot for the branch can be annulled if the
+branch is true, we might represent this as follows:
+
+@smallexample
+(define_delay (eq_attr "type" "branch")
+   [(eq_attr "type" "!branch,call")
+    (eq_attr "type" "!branch,call")
+    (nil)])
+
+(define_delay (eq_attr "type" "call")
+              [(eq_attr "type" "!branch,call") (nil) (nil)
+               (eq_attr "type" "!branch,call") (nil) (nil)])
+@end smallexample
+@c the above is *still* too long.  --mew 4feb93
+
+@node Function Units
+@subsection Specifying Function Units
+@cindex function units, for scheduling
+
+On most RISC machines, there are instructions whose results are not
+available for a specific number of cycles.  Common cases are instructions
+that load data from memory.  On many machines, a pipeline stall will result
+if the data is referenced too soon after the load instruction.
+
+In addition, many newer microprocessors have multiple function units, usually
+one for integer and one for floating point, and often will incur pipeline
+stalls when a result that is needed is not yet ready.
+
+The descriptions in this section allow the specification of how much
+time must elapse between the execution of an instruction and the time
+when its result is used.  It also allows specification of when the
+execution of an instruction will delay execution of similar instructions
+due to function unit conflicts.
+
+For the purposes of the specifications in this section, a machine is
+divided into @dfn{function units}, each of which execute a specific
+class of instructions in first-in-first-out order.  Function units that
+accept one instruction each cycle and allow a result to be used in the
+succeeding instruction (usually via forwarding) need not be specified.
+Classic RISC microprocessors will normally have a single function unit,
+which we can call @samp{memory}.  The newer ``superscalar'' processors
+will often have function units for floating point operations, usually at
+least a floating point adder and multiplier.
+
+@findex define_function_unit
+Each usage of a function units by a class of insns is specified with a
+@code{define_function_unit} expression, which looks like this:
+
+@smallexample
+(define_function_unit @var{name} @var{multiplicity} @var{simultaneity}
+                      @var{test} @var{ready-delay} @var{issue-delay}
+                     [@var{conflict-list}])
+@end smallexample
+
+@var{name} is a string giving the name of the function unit.
+
+@var{multiplicity} is an integer specifying the number of identical
+units in the processor.  If more than one unit is specified, they will
+be scheduled independently.  Only truly independent units should be
+counted; a pipelined unit should be specified as a single unit.  (The
+only common example of a machine that has multiple function units for a
+single instruction class that are truly independent and not pipelined
+are the two multiply and two increment units of the CDC 6600.)
+
+@var{simultaneity} specifies the maximum number of insns that can be
+executing in each instance of the function unit simultaneously or zero
+if the unit is pipelined and has no limit.
+
+All @code{define_function_unit} definitions referring to function unit
+@var{name} must have the same name and values for @var{multiplicity} and
+@var{simultaneity}.
+
+@var{test} is an attribute test that selects the insns we are describing
+in this definition.  Note that an insn may use more than one function
+unit and a function unit may be specified in more than one
+@code{define_function_unit}.
+
+@var{ready-delay} is an integer that specifies the number of cycles
+after which the result of the instruction can be used without
+introducing any stalls.
+
+@var{issue-delay} is an integer that specifies the number of cycles
+after the instruction matching the @var{test} expression begins using
+this unit until a subsequent instruction can begin.  A cost of @var{N}
+indicates an @var{N-1} cycle delay.  A subsequent instruction may also
+be delayed if an earlier instruction has a longer @var{ready-delay}
+value.  This blocking effect is computed using the @var{simultaneity},
+@var{ready-delay}, @var{issue-delay}, and @var{conflict-list} terms.
+For a normal non-pipelined function unit, @var{simultaneity} is one, the
+unit is taken to block for the @var{ready-delay} cycles of the executing
+insn, and smaller values of @var{issue-delay} are ignored.
+
+@var{conflict-list} is an optional list giving detailed conflict costs
+for this unit.  If specified, it is a list of condition test expressions
+to be applied to insns chosen to execute in @var{name} following the
+particular insn matching @var{test} that is already executing in
+@var{name}.  For each insn in the list, @var{issue-delay} specifies the
+conflict cost; for insns not in the list, the cost is zero.  If not
+specified, @var{conflict-list} defaults to all instructions that use the
+function unit.
+
+Typical uses of this vector are where a floating point function unit can
+pipeline either single- or double-precision operations, but not both, or
+where a memory unit can pipeline loads, but not stores, etc.
+
+As an example, consider a classic RISC machine where the result of a
+load instruction is not available for two cycles (a single ``delay''
+instruction is required) and where only one load instruction can be executed
+simultaneously.  This would be specified as:
+
+@smallexample
+(define_function_unit "memory" 1 1 (eq_attr "type" "load") 2 0)
+@end smallexample
+
+For the case of a floating point function unit that can pipeline either
+single or double precision, but not both, the following could be specified:
+
+@smallexample
+(define_function_unit
+   "fp" 1 0 (eq_attr "type" "sp_fp") 4 4 [(eq_attr "type" "dp_fp")])
+(define_function_unit
+   "fp" 1 0 (eq_attr "type" "dp_fp") 4 4 [(eq_attr "type" "sp_fp")])
+@end smallexample
+
+@strong{Note:} The scheduler attempts to avoid function unit conflicts
+and uses all the specifications in the @code{define_function_unit}
+expression.  It has recently come to our attention that these
+specifications may not allow modeling of some of the newer
+``superscalar'' processors that have insns using multiple pipelined
+units.  These insns will cause a potential conflict for the second unit
+used during their execution and there is no way of representing that
+conflict.  We welcome any examples of how function unit conflicts work
+in such processors and suggestions for their representation.
+
+@node Conditional Execution
+@section Conditional Execution
+@cindex conditional execution
+@cindex predication
+
+A number of architectures provide for some form of conditional
+execution, or predication.  The hallmark of this feature is the
+ability to nullify most of the instructions in the instruction set.
+When the instruction set is large and not entirely symmetric, it
+can be quite tedious to describe these forms directly in the
+@file{.md} file.  An alternative is the @code{define_cond_exec} template.
+
+@findex define_cond_exec
+@smallexample
+(define_cond_exec
+  [@var{predicate-pattern}]
+  "@var{condition}"
+  "@var{output-template}")
+@end smallexample
+
+@var{predicate-pattern} is the condition that must be true for the
+insn to be executed at runtime and should match a relational operator.
+One can use @code{match_operator} to match several relational operators
+at once.  Any @code{match_operand} operands must have no more than one
+alternative.
+
+@var{condition} is a C expression that must be true for the generated
+pattern to match.
+
+@findex current_insn_predicate
+@var{output-template} is a string similar to the @code{define_insn}
+output template (@pxref{Output Template}), except that the @samp{*}
+and @samp{@@} special cases do not apply.  This is only useful if the
+assembly text for the predicate is a simple prefix to the main insn.
+In order to handle the general case, there is a global variable
+@code{current_insn_predicate} that will contain the entire predicate
+if the current insn is predicated, and will otherwise be @code{NULL}.
+
+When @code{define_cond_exec} is used, an implicit reference to
+the @code{predicable} instruction attribute is made.
+@xref{Insn Attributes}.  This attribute must be boolean (i.e.@: have
+exactly two elements in its @var{list-of-values}).  Further, it must
+not be used with complex expressions.  That is, the default and all
+uses in the insns must be a simple constant, not dependent on the
+alternative or anything else.
+
+For each @code{define_insn} for which the @code{predicable}
+attribute is true, a new @code{define_insn} pattern will be
+generated that matches a predicated version of the instruction.
+For example,
+
+@smallexample
+(define_insn "addsi"
+  [(set (match_operand:SI 0 "register_operand" "r")
+        (plus:SI (match_operand:SI 1 "register_operand" "r")
+                 (match_operand:SI 2 "register_operand" "r")))]
+  "@var{test1}"
+  "add %2,%1,%0")
+
+(define_cond_exec
+  [(ne (match_operand:CC 0 "register_operand" "c")
+       (const_int 0))]
+  "@var{test2}"
+  "(%0)")
+@end smallexample
+
+@noindent
+generates a new pattern
+
+@smallexample
+(define_insn ""
+  [(cond_exec
+     (ne (match_operand:CC 3 "register_operand" "c") (const_int 0))
+     (set (match_operand:SI 0 "register_operand" "r")
+          (plus:SI (match_operand:SI 1 "register_operand" "r")
+                   (match_operand:SI 2 "register_operand" "r"))))]
+  "(@var{test2}) && (@var{test1})"
+  "(%3) add %2,%1,%0")
+@end smallexample
+
+@node Constant Definitions
+@section Constant Definitions
+@cindex constant definitions
+@findex define_constants
+
+Using literal constants inside instruction patterns reduces legibility and
+can be a maintenance problem.
+
+To overcome this problem, you may use the @code{define_constants}
+expression.  It contains a vector of name-value pairs.  From that
+point on, wherever any of the names appears in the MD file, it is as
+if the corresponding value had been written instead.  You may use
+@code{define_constants} multiple times; each appearance adds more
+constants to the table.  It is an error to redefine a constant with
+a different value.
+
+To come back to the a29k load multiple example, instead of
+
+@smallexample
+(define_insn ""
+  [(match_parallel 0 "load_multiple_operation"
+     [(set (match_operand:SI 1 "gpc_reg_operand" "=r")
+           (match_operand:SI 2 "memory_operand" "m"))
+      (use (reg:SI 179))
+      (clobber (reg:SI 179))])]
+  ""
+  "loadm 0,0,%1,%2")
+@end smallexample
+
+You could write:
+
+@smallexample
+(define_constants [
+    (R_BP 177)
+    (R_FC 178)
+    (R_CR 179)
+    (R_Q  180)
+])
+
+(define_insn ""
+  [(match_parallel 0 "load_multiple_operation"
+     [(set (match_operand:SI 1 "gpc_reg_operand" "=r")
+           (match_operand:SI 2 "memory_operand" "m"))
+      (use (reg:SI R_CR))
+      (clobber (reg:SI R_CR))])]
+  ""
+  "loadm 0,0,%1,%2")
+@end smallexample
+
+The constants that are defined with a define_constant are also output
+in the insn-codes.h header file as #defines.
+@end ifset
diff --git a/contrib/gcc/doc/objc.texi b/contrib/gcc/doc/objc.texi
new file mode 100644
index 0000000..d3fd775
--- /dev/null
+++ b/contrib/gcc/doc/objc.texi
@@ -0,0 +1,458 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+@c 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Objective-C
+@comment  node-name,  next,  previous,  up
+
+@chapter GNU Objective-C runtime features
+
+This document is meant to describe some of the GNU Objective-C runtime
+features.  It is not intended to teach you Objective-C, there are several
+resources on the Internet that present the language.  Questions and
+comments about this document to Ovidiu Predescu
+@email{ovidiu@@cup.hp.com}.
+
+@menu
+* Executing code before main::
+* Type encoding::
+* Garbage Collection::
+* Constant string objects::
+* compatibility_alias::
+@end menu
+
+@node Executing code before main, Type encoding, Objective-C, Objective-C
+@section @code{+load}: Executing code before main
+
+
+The GNU Objective-C runtime provides a way that allows you to execute
+code before the execution of the program enters the @code{main}
+function.  The code is executed on a per-class and a per-category basis,
+through a special class method @code{+load}.
+
+This facility is very useful if you want to initialize global variables
+which can be accessed by the program directly, without sending a message
+to the class first.  The usual way to initialize global variables, in the
+@code{+initialize} method, might not be useful because
+@code{+initialize} is only called when the first message is sent to a
+class object, which in some cases could be too late.
+
+Suppose for example you have a @code{FileStream} class that declares
+@code{Stdin}, @code{Stdout} and @code{Stderr} as global variables, like
+below:
+
+@example
+
+FileStream *Stdin = nil;
+FileStream *Stdout = nil;
+FileStream *Stderr = nil;
+
+@@implementation FileStream
+
++ (void)initialize
+@{
+    Stdin = [[FileStream new] initWithFd:0];
+    Stdout = [[FileStream new] initWithFd:1];
+    Stderr = [[FileStream new] initWithFd:2];
+@}
+
+/* Other methods here */
+@@end
+
+@end example
+
+In this example, the initialization of @code{Stdin}, @code{Stdout} and
+@code{Stderr} in @code{+initialize} occurs too late.  The programmer can
+send a message to one of these objects before the variables are actually
+initialized, thus sending messages to the @code{nil} object.  The
+@code{+initialize} method which actually initializes the global
+variables is not invoked until the first message is sent to the class
+object.  The solution would require these variables to be initialized
+just before entering @code{main}.
+
+The correct solution of the above problem is to use the @code{+load}
+method instead of @code{+initialize}:
+
+@example
+
+@@implementation FileStream
+
++ (void)load
+@{
+    Stdin = [[FileStream new] initWithFd:0];
+    Stdout = [[FileStream new] initWithFd:1];
+    Stderr = [[FileStream new] initWithFd:2];
+@}
+
+/* Other methods here */
+@@end
+
+@end example
+
+The @code{+load} is a method that is not overridden by categories.  If a
+class and a category of it both implement @code{+load}, both methods are
+invoked.  This allows some additional initializations to be performed in
+a category.
+
+This mechanism is not intended to be a replacement for @code{+initialize}.
+You should be aware of its limitations when you decide to use it
+instead of @code{+initialize}.
+
+@menu
+* What you can and what you cannot do in +load::
+@end menu
+
+
+@node What you can and what you cannot do in +load,  , Executing code before main, Executing code before main
+@subsection What you can and what you cannot do in @code{+load}
+
+The @code{+load} implementation in the GNU runtime guarantees you the following
+things:
+
+@itemize @bullet
+
+@item
+you can write whatever C code you like;
+
+@item
+you can send messages to Objective-C constant strings (@code{@@"this is a
+constant string"});
+
+@item
+you can allocate and send messages to objects whose class is implemented
+in the same file;
+
+@item
+the @code{+load} implementation of all super classes of a class are executed before the @code{+load} of that class is executed;
+
+@item
+the @code{+load} implementation of a class is executed before the
+@code{+load} implementation of any category.
+
+@end itemize
+
+In particular, the following things, even if they can work in a
+particular case, are not guaranteed:
+
+@itemize @bullet
+
+@item
+allocation of or sending messages to arbitrary objects;
+
+@item
+allocation of or sending messages to objects whose classes have a
+category implemented in the same file;
+
+@end itemize
+
+You should make no assumptions about receiving @code{+load} in sibling
+classes when you write @code{+load} of a class.  The order in which
+sibling classes receive @code{+load} is not guaranteed.
+
+The order in which @code{+load} and @code{+initialize} are called could
+be problematic if this matters.  If you don't allocate objects inside
+@code{+load}, it is guaranteed that @code{+load} is called before
+@code{+initialize}.  If you create an object inside @code{+load} the
+@code{+initialize} method of object's class is invoked even if
+@code{+load} was not invoked.  Note if you explicitly call @code{+load}
+on a class, @code{+initialize} will be called first.  To avoid possible
+problems try to implement only one of these methods.
+
+The @code{+load} method is also invoked when a bundle is dynamically
+loaded into your running program.  This happens automatically without any
+intervening operation from you.  When you write bundles and you need to
+write @code{+load} you can safely create and send messages to objects whose
+classes already exist in the running program.  The same restrictions as
+above apply to classes defined in bundle.
+
+
+
+@node Type encoding, Garbage Collection, Executing code before main, Objective-C
+@section Type encoding
+
+The Objective-C compiler generates type encodings for all the
+types.  These type encodings are used at runtime to find out information
+about selectors and methods and about objects and classes.
+
+The types are encoded in the following way:
+
+@c @sp 1
+
+@multitable @columnfractions .25 .75
+@item @code{char}
+@tab @code{c}
+@item @code{unsigned char}
+@tab @code{C}
+@item @code{short}
+@tab @code{s}
+@item @code{unsigned short}
+@tab @code{S}
+@item @code{int}
+@tab @code{i}
+@item @code{unsigned int}
+@tab @code{I}
+@item @code{long}
+@tab @code{l}
+@item @code{unsigned long}
+@tab @code{L}
+@item @code{long long}
+@tab @code{q}
+@item @code{unsigned long long}
+@tab @code{Q}
+@item @code{float}
+@tab @code{f}
+@item @code{double}
+@tab @code{d}
+@item @code{void}
+@tab @code{v}
+@item @code{id}
+@tab @code{@@}
+@item @code{Class}
+@tab @code{#}
+@item @code{SEL}
+@tab @code{:}
+@item @code{char*}
+@tab @code{*}
+@item unknown type
+@tab @code{?}
+@item bit-fields
+@tab @code{b} followed by the starting position of the bit-field, the type of the bit-field and the size of the bit-field (the bit-fields encoding was changed from the NeXT's compiler encoding, see below)
+@end multitable
+
+@c @sp 1
+
+The encoding of bit-fields has changed to allow bit-fields to be properly
+handled by the runtime functions that compute sizes and alignments of
+types that contain bit-fields.  The previous encoding contained only the
+size of the bit-field.  Using only this information it is not possible to
+reliably compute the size occupied by the bit-field.  This is very
+important in the presence of the Boehm's garbage collector because the
+objects are allocated using the typed memory facility available in this
+collector.  The typed memory allocation requires information about where
+the pointers are located inside the object.
+
+The position in the bit-field is the position, counting in bits, of the
+bit closest to the beginning of the structure.
+
+The non-atomic types are encoded as follows:
+
+@c @sp 1
+
+@multitable @columnfractions .2 .8
+@item pointers
+@tab @samp{^} followed by the pointed type.
+@item arrays
+@tab @samp{[} followed by the number of elements in the array followed by the type of the elements followed by @samp{]}
+@item structures
+@tab @samp{@{} followed by the name of the structure (or @samp{?} if the structure is unnamed), the @samp{=} sign, the type of the members and by @samp{@}}
+@item unions
+@tab @samp{(} followed by the name of the structure (or @samp{?} if the union is unnamed), the @samp{=} sign, the type of the members followed by @samp{)}
+@end multitable
+
+Here are some types and their encodings, as they are generated by the
+compiler on an i386 machine:
+
+@sp 1
+
+@multitable @columnfractions .25 .75
+@item Objective-C type
+@tab Compiler encoding
+@item
+@example
+int a[10];
+@end example
+@tab @code{[10i]}
+@item
+@example
+struct @{
+  int i;
+  float f[3];
+  int a:3;
+  int b:2;
+  char c;
+@}
+@end example
+@tab @code{@{?=i[3f]b128i3b131i2c@}}
+@end multitable
+
+@sp 1
+
+In addition to the types the compiler also encodes the type
+specifiers.  The table below describes the encoding of the current
+Objective-C type specifiers:
+
+@sp 1
+
+@multitable @columnfractions .25 .75
+@item Specifier
+@tab Encoding
+@item @code{const}
+@tab @code{r}
+@item @code{in}
+@tab @code{n}
+@item @code{inout}
+@tab @code{N}
+@item @code{out}
+@tab @code{o}
+@item @code{bycopy}
+@tab @code{O}
+@item @code{oneway}
+@tab @code{V}
+@end multitable
+
+@sp 1
+
+The type specifiers are encoded just before the type.  Unlike types
+however, the type specifiers are only encoded when they appear in method
+argument types.
+
+
+@node Garbage Collection, Constant string objects, Type encoding, Objective-C
+@section Garbage Collection
+
+Support for a new memory management policy has been added by using a
+powerful conservative garbage collector, known as the
+Boehm-Demers-Weiser conservative garbage collector.  It is available from
+@w{@uref{http://www.hpl.hp.com/personal/Hans_Boehm/gc/}}.
+
+To enable the support for it you have to configure the compiler using an
+additional argument, @w{@option{--enable-objc-gc}}.  You need to have
+garbage collector installed before building the compiler.  This will
+build an additional runtime library which has several enhancements to
+support the garbage collector.  The new library has a new name,
+@file{libobjc_gc.a} to not conflict with the non-garbage-collected
+library.
+
+When the garbage collector is used, the objects are allocated using the
+so-called typed memory allocation mechanism available in the
+Boehm-Demers-Weiser collector.  This mode requires precise information on
+where pointers are located inside objects.  This information is computed
+once per class, immediately after the class has been initialized.
+
+There is a new runtime function @code{class_ivar_set_gcinvisible()}
+which can be used to declare a so-called @dfn{weak pointer}
+reference.  Such a pointer is basically hidden for the garbage collector;
+this can be useful in certain situations, especially when you want to
+keep track of the allocated objects, yet allow them to be
+collected.  This kind of pointers can only be members of objects, you
+cannot declare a global pointer as a weak reference.  Every type which is
+a pointer type can be declared a weak pointer, including @code{id},
+@code{Class} and @code{SEL}.
+
+Here is an example of how to use this feature.  Suppose you want to
+implement a class whose instances hold a weak pointer reference; the
+following class does this:
+
+@example
+
+@@interface WeakPointer : Object
+@{
+    const void* weakPointer;
+@}
+
+- initWithPointer:(const void*)p;
+- (const void*)weakPointer;
+@@end
+
+
+@@implementation WeakPointer
+
++ (void)initialize
+@{
+  class_ivar_set_gcinvisible (self, "weakPointer", YES);
+@}
+
+- initWithPointer:(const void*)p
+@{
+  weakPointer = p;
+  return self;
+@}
+
+- (const void*)weakPointer
+@{
+  return weakPointer;
+@}
+
+@@end
+
+@end example
+
+Weak pointers are supported through a new type character specifier
+represented by the @samp{!} character.  The
+@code{class_ivar_set_gcinvisible()} function adds or removes this
+specifier to the string type description of the instance variable named
+as argument.
+
+@c =========================================================================
+@node Constant string objects
+@section Constant string objects
+
+GNU Objective-C provides constant string objects that are generated
+directly by the compiler.  You declare a constant string object by
+prefixing a C constant string with the character @samp{@@}:
+
+@example
+  id myString = @@"this is a constant string object";
+@end example
+
+The constant string objects are usually instances of the
+@code{NXConstantString} class which is provided by the GNU Objective-C
+runtime.  To get the definition of this class you must include the
+@file{objc/NXConstStr.h} header file.
+
+User defined libraries may want to implement their own constant string
+class.  To be able to support them, the GNU Objective-C compiler provides
+a new command line options @option{-fconstant-string-class=@var{class-name}}.
+The provided class should adhere to a strict structure, the same
+as @code{NXConstantString}'s structure:
+
+@example
+
+@@interface NXConstantString : Object
+@{
+  char *c_string;
+  unsigned int len;
+@}
+@@end
+
+@end example
+
+User class libraries may choose to inherit the customized constant
+string class from a different class than @code{Object}.  There is no
+requirement in the methods the constant string class has to implement.
+
+When a file is compiled with the @option{-fconstant-string-class} option,
+all the constant string objects will be instances of the class specified
+as argument to this option.  It is possible to have multiple compilation
+units referring to different constant string classes, neither the
+compiler nor the linker impose any restrictions in doing this.
+
+@c =========================================================================
+@node compatibility_alias
+@section compatibility_alias
+
+This is a feature of the Objective-C compiler rather than of the
+runtime, anyway since it is documented nowhere and its existence was
+forgotten, we are documenting it here.
+
+The keyword @code{@@compatibility_alias} allows you to define a class name
+as equivalent to another class name.  For example:
+
+@example
+@@compatibility_alias WOApplication GSWApplication;
+@end example
+
+tells the compiler that each time it encounters @code{WOApplication} as
+a class name, it should replace it with @code{GSWApplication} (that is,
+@code{WOApplication} is just an alias for @code{GSWApplication}).
+
+There are some constraints on how this can be used---
+
+@itemize @bullet
+
+@item @code{WOApplication} (the alias) must not be an existing class;
+
+@item @code{GSWApplication} (the real class) must be an existing class.
+
+@end itemize
diff --git a/contrib/gcc/doc/passes.texi b/contrib/gcc/doc/passes.texi
new file mode 100644
index 0000000..f248056
--- /dev/null
+++ b/contrib/gcc/doc/passes.texi
@@ -0,0 +1,659 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+@c 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Passes
+@chapter Passes and Files of the Compiler
+@cindex passes and files of the compiler
+@cindex files and passes of the compiler
+@cindex compiler passes and files
+
+@cindex top level of compiler
+The overall control structure of the compiler is in @file{toplev.c}.  This
+file is responsible for initialization, decoding arguments, opening and
+closing files, and sequencing the passes.
+
+@cindex parsing pass
+The parsing pass is invoked only once, to parse the entire input.  A
+high level tree representation is then generated from the input,
+one function at a time.  This tree code is then transformed into RTL
+intermediate code, and processed.  The files involved in transforming
+the trees into RTL are @file{expr.c}, @file{expmed.c}, and
+@file{stmt.c}.
+@c Note, the above files aren't strictly the only files involved. It's
+@c all over the place (function.c, final.c,etc).  However, those are
+@c the files that are supposed to be directly involved, and have
+@c their purpose listed as such, so i've only listed them.
+The order of trees that are processed, is not
+necessarily the same order they are generated from
+the input, due to deferred inlining, and other considerations.
+
+@findex rest_of_compilation
+@findex rest_of_decl_compilation
+Each time the parsing pass reads a complete function definition or
+top-level declaration, it calls either the function
+@code{rest_of_compilation}, or the function
+@code{rest_of_decl_compilation} in @file{toplev.c}, which are
+responsible for all further processing necessary, ending with output of
+the assembler language.  All other compiler passes run, in sequence,
+within @code{rest_of_compilation}.  When that function returns from
+compiling a function definition, the storage used for that function
+definition's compilation is entirely freed, unless it is an inline
+function, or was deferred for some reason (this can occur in
+templates, for example).
+(@pxref{Inline,,An Inline Function is As Fast As a Macro,gcc,Using the
+GNU Compiler Collection (GCC)}).
+
+Here is a list of all the passes of the compiler and their source files.
+Also included is a description of where debugging dumps can be requested
+with @option{-d} options.
+
+@itemize @bullet
+@item
+Parsing.  This pass reads the entire text of a function definition,
+constructing a high level tree representation.  (Because of the semantic
+analysis that takes place during this pass, it does more than is
+formally considered to be parsing.)
+
+The tree representation does not entirely follow C syntax, because it is
+intended to support other languages as well.
+
+Language-specific data type analysis is also done in this pass, and every
+tree node that represents an expression has a data type attached.
+Variables are represented as declaration nodes.
+
+The language-independent source files for parsing are
+@file{tree.c}, @file{fold-const.c}, and @file{stor-layout.c}.
+There are also header files @file{tree.h} and @file{tree.def}
+which define the format of the tree representation.
+
+C preprocessing, for language front ends, that want or require it, is
+performed by cpplib, which is covered in separate documentation.  In
+particular, the internals are covered in @xref{Top, ,Cpplib internals,
+cppinternals, Cpplib Internals}.
+
+@c Avoiding overfull is tricky here.
+The source files to parse C are
+@file{c-convert.c},
+@file{c-decl.c},
+@file{c-errors.c},
+@file{c-lang.c},
+@file{c-objc-common.c},
+@file{c-parse.in},
+@file{c-aux-info.c},
+and
+@file{c-typeck.c},
+along with a header file
+@file{c-tree.h}
+and some files shared with Objective-C and C++.
+
+The source files for parsing C++ are in @file{cp/}.
+They are @file{parse.y},
+@file{class.c},
+@file{cvt.c}, @file{decl.c}, @file{decl2.c},
+@file{except.c},
+@file{expr.c}, @file{init.c}, @file{lex.c},
+@file{method.c}, @file{ptree.c},
+@file{search.c}, @file{spew.c},
+@file{semantics.c}, @file{tree.c},
+@file{typeck2.c}, and
+@file{typeck.c}, along with header files @file{cp-tree.def},
+@file{cp-tree.h}, and @file{decl.h}.
+
+The special source files for parsing Objective-C are in @file{objc/}.
+They are @file{objc-act.c}, @file{objc-tree.def}, and @file{objc-act.h}.
+Certain C-specific files are used for this as well.
+
+The files
+@file{c-common.c},
+@file{c-common.def},
+@file{c-format.c},
+@file{c-pragma.c},
+@file{c-semantics.c},
+and
+@file{c-lex.c},
+along with header files
+@file{c-common.h},
+@file{c-dump.h},
+@file{c-lex.h},
+and
+@file{c-pragma.h},
+are also used for all of the above languages.
+
+
+@cindex Tree optimization
+@item
+Tree optimization.   This is the optimization of the tree
+representation, before converting into RTL code.
+
+@cindex inline on trees, automatic
+Currently, the main optimization performed here is tree-based
+inlining.
+This is implemented in @file{tree-inline.c} and used by both C and C++.  
+Note that tree based inlining turns off rtx based inlining (since it's more
+powerful, it would be a waste of time to do rtx based inlining in
+addition).
+
+@cindex constant folding
+@cindex arithmetic simplifications
+@cindex simplifications, arithmetic
+Constant folding and some arithmetic simplifications are also done
+during this pass, on the tree representation.
+The routines that perform these tasks are located in @file{fold-const.c}.
+
+@cindex RTL generation
+@item
+RTL generation.  This is the conversion of syntax tree into RTL code.
+
+@cindex target-parameter-dependent code
+This is where the bulk of target-parameter-dependent code is found,
+since often it is necessary for strategies to apply only when certain
+standard kinds of instructions are available.  The purpose of named
+instruction patterns is to provide this information to the RTL
+generation pass.
+
+@cindex tail recursion optimization
+Optimization is done in this pass for @code{if}-conditions that are
+comparisons, boolean operations or conditional expressions.  Tail
+recursion is detected at this time also.  Decisions are made about how
+best to arrange loops and how to output @code{switch} statements.
+
+@c Avoiding overfull is tricky here.
+The source files for RTL generation include
+@file{stmt.c},
+@file{calls.c},
+@file{expr.c},
+@file{explow.c},
+@file{expmed.c},
+@file{function.c},
+@file{optabs.c}
+and @file{emit-rtl.c}.
+Also, the file
+@file{insn-emit.c}, generated from the machine description by the
+program @code{genemit}, is used in this pass.  The header file
+@file{expr.h} is used for communication within this pass.
+
+@findex genflags
+@findex gencodes
+The header files @file{insn-flags.h} and @file{insn-codes.h},
+generated from the machine description by the programs @code{genflags}
+and @code{gencodes}, tell this pass which standard names are available
+for use and which patterns correspond to them.
+
+Aside from debugging information output, none of the following passes
+refers to the tree structure representation of the function (only
+part of which is saved).
+
+@cindex inline on rtx, automatic
+The decision of whether the function can and should be expanded inline
+in its subsequent callers is made at the end of rtl generation.  The
+function must meet certain criteria, currently related to the size of
+the function and the types and number of parameters it has.  Note that
+this function may contain loops, recursive calls to itself
+(tail-recursive functions can be inlined!), gotos, in short, all
+constructs supported by GCC@.  The file @file{integrate.c} contains
+the code to save a function's rtl for later inlining and to inline that
+rtl when the function is called.  The header file @file{integrate.h}
+is also used for this purpose.
+
+@opindex dr
+The option @option{-dr} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.rtl} to
+the input file name.
+
+@c Should the exception handling pass be talked about here?
+
+@cindex sibling call optimization
+@item
+Sibiling call optimization.   This pass performs tail recursion
+elimination, and tail and sibling call optimizations.  The purpose of
+these optimizations is to reduce the overhead of function calls,
+whenever possible.
+
+The source file of this pass is @file{sibcall.c}
+
+@opindex di
+The option @option{-di} causes a debugging dump of the RTL code after
+this pass is run.  This dump file's name is made by appending
+@samp{.sibling} to the input file name.
+
+@cindex jump optimization
+@cindex unreachable code
+@cindex dead code
+@item
+Jump optimization.  This pass simplifies jumps to the following
+instruction, jumps across jumps, and jumps to jumps.  It deletes
+unreferenced labels and unreachable code, except that unreachable code
+that contains a loop is not recognized as unreachable in this pass.
+(Such loops are deleted later in the basic block analysis.)  It also
+converts some code originally written with jumps into sequences of
+instructions that directly set values from the results of comparisons,
+if the machine has such instructions.
+
+Jump optimization is performed two or three times.  The first time is
+immediately following RTL generation.  The second time is after CSE,
+but only if CSE says repeated jump optimization is needed.  The
+last time is right before the final pass.  That time, cross-jumping
+and deletion of no-op move instructions are done together with the
+optimizations described above.
+
+The source file of this pass is @file{jump.c}.
+
+@opindex dj
+The option @option{-dj} causes a debugging dump of the RTL code after
+this pass is run for the first time.  This dump file's name is made by
+appending @samp{.jump} to the input file name.
+
+
+@cindex register use analysis
+@item
+Register scan.  This pass finds the first and last use of each
+register, as a guide for common subexpression elimination.  Its source
+is in @file{regclass.c}.
+
+@cindex jump threading
+@item
+@opindex fthread-jumps
+Jump threading.  This pass detects a condition jump that branches to an
+identical or inverse test.  Such jumps can be @samp{threaded} through
+the second conditional test.  The source code for this pass is in
+@file{jump.c}.  This optimization is only performed if
+@option{-fthread-jumps} is enabled.
+
+@cindex SSA optimizations
+@cindex Single Static Assignment optimizations
+@opindex fssa
+@item
+Static Single Assignment (SSA) based optimization passes.  The
+SSA conversion passes (to/from) are turned on by the @option{-fssa}
+option (it is also done automatically if you enable an SSA optimization pass).
+These passes utilize a form called Static Single Assignment.  In SSA form,
+each variable (pseudo register) is only set once, giving you def-use
+and use-def chains for free, and enabling a lot more optimization
+passes to be run in linear time.
+Conversion to and from SSA form is handled by functions in
+@file{ssa.c}.
+
+@opindex de
+The option @option{-de} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.ssa} to
+the input file name.
+@itemize @bullet
+@cindex SSA Conditional Constant Propagation
+@cindex Conditional Constant Propagation, SSA based
+@cindex conditional constant propagation
+@opindex fssa-ccp
+@item
+SSA Conditional Constant Propagation.  Turned on by the @option{-fssa-ccp}
+SSA Aggressive Dead Code Elimination.  Turned on by the @option{-fssa-dce}
+option.  This pass performs conditional constant propagation to simplify
+instructions including conditional branches.  This pass is more aggressive
+than the constant propgation done by the CSE and GCSE pases, but operates
+in linear time.
+
+@opindex dW
+The option @option{-dW} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.ssaccp} to
+the input file name.
+
+@cindex SSA DCE
+@cindex DCE, SSA based
+@cindex dead code elimination
+@opindex fssa-dce
+@item
+SSA Aggressive Dead Code Elimination.  Turned on by the @option{-fssa-dce}
+option.  This pass performs elimination of code considered unnecessary because
+it has no externally visible effects on the program.  It operates in
+linear time.
+
+@opindex dX
+The option @option{-dX} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.ssadce} to
+the input file name.
+@end itemize
+
+@cindex common subexpression elimination
+@cindex constant propagation
+@item
+Common subexpression elimination.  This pass also does constant
+propagation.  Its source files are @file{cse.c}, and @file{cselib.c}.
+If constant  propagation causes conditional jumps to become
+unconditional or to become no-ops, jump optimization is run again when
+CSE is finished.
+
+@opindex ds
+The option @option{-ds} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.cse} to
+the input file name.
+
+@cindex global common subexpression elimination
+@cindex constant propagation
+@cindex copy propagation
+@item
+Global common subexpression elimination.  This pass performs two
+different types of GCSE  depending on whether you are optimizing for
+size or not (LCM based GCSE tends to increase code size for a gain in
+speed, while Morel-Renvoise based GCSE does not).
+When optimizing for size, GCSE is done using Morel-Renvoise Partial
+Redundancy Elimination, with the exception that it does not try to move
+invariants out of loops---that is left to  the loop optimization pass.
+If MR PRE GCSE is done, code hoisting (aka unification) is also done, as
+well as load motion.
+If you are optimizing for speed, LCM (lazy code motion) based GCSE is
+done.  LCM is based on the work of Knoop, Ruthing, and Steffen.  LCM
+based GCSE also does loop invariant code motion.  We also perform load
+and store motion when optimizing for speed.
+Regardless of which type of GCSE is used, the GCSE pass also performs
+global constant and  copy propagation.
+
+The source file for this pass is @file{gcse.c}, and the LCM routines
+are in @file{lcm.c}.
+
+@opindex dG
+The option @option{-dG} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.gcse} to
+the input file name.
+
+@cindex loop optimization
+@cindex code motion
+@cindex strength-reduction
+@item
+Loop optimization.  This pass moves constant expressions out of loops,
+and optionally does strength-reduction and loop unrolling as well.
+Its source files are @file{loop.c} and @file{unroll.c}, plus the header
+@file{loop.h} used for communication between them.  Loop unrolling uses
+some functions in @file{integrate.c} and the header @file{integrate.h}.
+Loop dependency analysis routines are contained in @file{dependence.c}.
+
+@opindex dL
+The option @option{-dL} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.loop} to
+the input file name.
+
+@item
+@opindex frerun-cse-after-loop
+If @option{-frerun-cse-after-loop} was enabled, a second common
+subexpression elimination pass is performed after the loop optimization
+pass.  Jump threading is also done again at this time if it was specified.
+
+@opindex dt
+The option @option{-dt} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.cse2} to
+the input file name.
+
+@cindex data flow analysis
+@cindex analysis, data flow
+@cindex basic blocks
+@item
+Data flow analysis (@file{flow.c}).  This pass divides the program
+into basic blocks (and in the process deletes unreachable loops); then
+it computes which pseudo-registers are live at each point in the
+program, and makes the first instruction that uses a value point at
+the instruction that computed the value.
+
+@cindex autoincrement/decrement analysis
+This pass also deletes computations whose results are never used, and
+combines memory references with add or subtract instructions to make
+autoincrement or autodecrement addressing.
+
+@opindex df
+The option @option{-df} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.flow} to
+the input file name.  If stupid register allocation is in use, this
+dump file reflects the full results of such allocation.
+
+@cindex instruction combination
+@item
+Instruction combination (@file{combine.c}).  This pass attempts to
+combine groups of two or three instructions that are related by data
+flow into single instructions.  It combines the RTL expressions for
+the instructions by substitution, simplifies the result using algebra,
+and then attempts to match the result against the machine description.
+
+@opindex dc
+The option @option{-dc} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.combine}
+to the input file name.
+
+@cindex if conversion
+@item
+If-conversion is a transformation that transforms control dependencies
+into data dependencies (IE it transforms conditional code into a
+single control stream).
+It is implemented in the file @file{ifcvt.c}.
+
+@opindex dE
+The option @option{-dE} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.ce} to
+the input file name.
+
+@cindex register movement
+@item
+Register movement (@file{regmove.c}).  This pass looks for cases where
+matching constraints would force an instruction to need a reload, and
+this reload would be a register-to-register move.  It then attempts
+to change the registers used by the instruction to avoid the move
+instruction.
+
+@opindex dN
+The option @option{-dN} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.regmove}
+to the input file name.
+
+@cindex instruction scheduling
+@cindex scheduling, instruction
+@item
+Instruction scheduling (@file{sched.c}).  This pass looks for
+instructions whose output will not be available by the time that it is
+used in subsequent instructions.  (Memory loads and floating point
+instructions often have this behavior on RISC machines).  It re-orders
+instructions within a basic block to try to separate the definition and
+use of items that otherwise would cause pipeline stalls.
+
+Instruction scheduling is performed twice.  The first time is immediately
+after instruction combination and the second is immediately after reload.
+
+@opindex dS
+The option @option{-dS} causes a debugging dump of the RTL code after this
+pass is run for the first time.  The dump file's name is made by
+appending @samp{.sched} to the input file name.
+
+@cindex register class preference pass
+@item
+Register class preferencing.  The RTL code is scanned to find out
+which register class is best for each pseudo register.  The source
+file is @file{regclass.c}.
+
+@cindex register allocation
+@cindex local register allocation
+@item
+Local register allocation (@file{local-alloc.c}).  This pass allocates
+hard registers to pseudo registers that are used only within one basic
+block.  Because the basic block is linear, it can use fast and
+powerful techniques to do a very good job.
+
+@opindex dl
+The option @option{-dl} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.lreg} to
+the input file name.
+
+@cindex global register allocation
+@item
+Global register allocation (@file{global.c}).  This pass
+allocates hard registers for the remaining pseudo registers (those
+whose life spans are not contained in one basic block).
+
+@cindex reloading
+@item
+Reloading.  This pass renumbers pseudo registers with the hardware
+registers numbers they were allocated.  Pseudo registers that did not
+get hard registers are replaced with stack slots.  Then it finds
+instructions that are invalid because a value has failed to end up in
+a register, or has ended up in a register of the wrong kind.  It fixes
+up these instructions by reloading the problematical values
+temporarily into registers.  Additional instructions are generated to
+do the copying.
+
+The reload pass also optionally eliminates the frame pointer and inserts
+instructions to save and restore call-clobbered registers around calls.
+
+Source files are @file{reload.c} and @file{reload1.c}, plus the header
+@file{reload.h} used for communication between them.
+
+@opindex dg
+The option @option{-dg} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.greg} to
+the input file name.
+
+@cindex instruction scheduling
+@cindex scheduling, instruction
+@item
+Instruction scheduling is repeated here to try to avoid pipeline stalls
+due to memory loads generated for spilled pseudo registers.
+
+@opindex dR
+The option @option{-dR} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.sched2}
+to the input file name.
+
+@cindex basic block reordering
+@cindex reordering, block
+@item
+Basic block reordering.  This pass implements profile guided code
+positioning.  If profile information is not available, various types of
+static analysis are performed to make the predictions normally coming
+from the profile feedback (IE execution frequency, branch probability,
+etc).  It is implemented in the file @file{bb-reorder.c}, and the
+various prediction routines are in @file{predict.c}.
+
+@opindex dB
+The option @option{-dB} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.bbro} to
+the input file name.
+
+@cindex cross-jumping
+@cindex no-op move instructions
+@item
+Jump optimization is repeated, this time including cross-jumping
+and deletion of no-op move instructions.
+
+@opindex dJ
+The option @option{-dJ} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.jump2}
+to the input file name.
+
+@cindex delayed branch scheduling
+@cindex scheduling, delayed branch
+@item
+Delayed branch scheduling.  This optional pass attempts to find
+instructions that can go into the delay slots of other instructions,
+usually jumps and calls.  The source file name is @file{reorg.c}.
+
+@opindex dd
+The option @option{-dd} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.dbr}
+to the input file name.
+
+@cindex branch shortening
+@item
+Branch shortening.  On many RISC machines, branch instructions have a
+limited range.  Thus, longer sequences of instructions must be used for
+long branches.  In this pass, the compiler figures out what how far each
+instruction will be from each other instruction, and therefore whether
+the usual instructions, or the longer sequences, must be used for each
+branch.
+
+@cindex register-to-stack conversion
+@item
+Conversion from usage of some hard registers to usage of a register
+stack may be done at this point.  Currently, this is supported only
+for the floating-point registers of the Intel 80387 coprocessor.   The
+source file name is @file{reg-stack.c}.
+
+@opindex dk
+The options @option{-dk} causes a debugging dump of the RTL code after
+this pass.  This dump file's name is made by appending @samp{.stack}
+to the input file name.
+
+@cindex final pass
+@cindex peephole optimization
+@item
+Final.  This pass outputs the assembler code for the function.  It is
+also responsible for identifying spurious test and compare
+instructions.  Machine-specific peephole optimizations are performed
+at the same time.  The function entry and exit sequences are generated
+directly as assembler code in this pass; they never exist as RTL@.
+
+The source files are @file{final.c} plus @file{insn-output.c}; the
+latter is generated automatically from the machine description by the
+tool @file{genoutput}.  The header file @file{conditions.h} is used
+for communication between these files.
+
+@cindex debugging information generation
+@item
+Debugging information output.  This is run after final because it must
+output the stack slot offsets for pseudo registers that did not get
+hard registers.  Source files are @file{dbxout.c} for DBX symbol table
+format, @file{sdbout.c} for SDB symbol table format,  @file{dwarfout.c}
+for DWARF symbol table format, files @file{dwarf2out.c} and
+@file{dwarf2asm.c} for DWARF2 symbol table format, and @file{vmsdbgout.c}
+for VMS debug symbol table format.
+@end itemize
+
+Some additional files are used by all or many passes:
+
+@itemize @bullet
+@item
+Every pass uses @file{machmode.def} and @file{machmode.h} which define
+the machine modes.
+
+@item
+Several passes use @file{real.h}, which defines the default
+representation of floating point constants and how to operate on them.
+
+@item
+All the passes that work with RTL use the header files @file{rtl.h}
+and @file{rtl.def}, and subroutines in file @file{rtl.c}.  The tools
+@code{gen*} also use these files to read and work with the machine
+description RTL@.
+
+@item
+All the tools that read the machine description use support routines
+found in @file{gensupport.c}, @file{errors.c}, and @file{read-rtl.c}.
+
+@findex genconfig
+@item
+Several passes refer to the header file @file{insn-config.h} which
+contains a few parameters (C macro definitions) generated
+automatically from the machine description RTL by the tool
+@code{genconfig}.
+
+@cindex instruction recognizer
+@item
+Several passes use the instruction recognizer, which consists of
+@file{recog.c} and @file{recog.h}, plus the files @file{insn-recog.c}
+and @file{insn-extract.c} that are generated automatically from the
+machine description by the tools @file{genrecog} and
+@file{genextract}.
+
+@item
+Several passes use the header files @file{regs.h} which defines the
+information recorded about pseudo register usage, and @file{basic-block.h}
+which defines the information recorded about basic blocks.
+
+@item
+@file{hard-reg-set.h} defines the type @code{HARD_REG_SET}, a bit-vector
+with a bit for each hard register, and some macros to manipulate it.
+This type is just @code{int} if the machine has few enough hard registers;
+otherwise it is an array of @code{int} and some of the macros expand
+into loops.
+
+@item
+Several passes use instruction attributes.  A definition of the
+attributes defined for a particular machine is in file
+@file{insn-attr.h}, which is generated from the machine description by
+the program @file{genattr}.  The file @file{insn-attrtab.c} contains
+subroutines to obtain the attribute values for insns.  It is generated
+from the machine description by the program @file{genattrtab}.
+@end itemize
diff --git a/contrib/gcc/doc/portability.texi b/contrib/gcc/doc/portability.texi
new file mode 100644
index 0000000..c3d8e39
--- /dev/null
+++ b/contrib/gcc/doc/portability.texi
@@ -0,0 +1,38 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+@c 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Portability
+@chapter GCC and Portability
+@cindex portability
+@cindex GCC and portability
+
+The main goal of GCC was to make a good, fast compiler for machines in
+the class that the GNU system aims to run on: 32-bit machines that address
+8-bit bytes and have several general registers.  Elegance, theoretical
+power and simplicity are only secondary.
+
+GCC gets most of the information about the target machine from a machine
+description which gives an algebraic formula for each of the machine's
+instructions.  This is a very clean way to describe the target.  But when
+the compiler needs information that is difficult to express in this
+fashion, I have not hesitated to define an ad-hoc parameter to the machine
+description.  The purpose of portability is to reduce the total work needed
+on the compiler; it was not of interest for its own sake.
+
+@cindex endianness
+@cindex autoincrement addressing, availability
+@findex abort
+GCC does not contain machine dependent code, but it does contain code
+that depends on machine parameters such as endianness (whether the most
+significant byte has the highest or lowest address of the bytes in a word)
+and the availability of autoincrement addressing.  In the RTL-generation
+pass, it is often necessary to have multiple strategies for generating code
+for a particular kind of syntax tree, strategies that are usable for different
+combinations of parameters.  Often I have not tried to address all possible
+cases, but only the common ones or only the ones that I have encountered.
+As a result, a new target may require additional strategies.  You will know
+if this happens because the compiler will call @code{abort}.  Fortunately,
+the new strategies can be added in a machine-independent fashion, and will
+affect only the target machines that need them.
diff --git a/contrib/gcc/doc/rtl.texi b/contrib/gcc/doc/rtl.texi
new file mode 100644
index 0000000..5b61409
--- /dev/null
+++ b/contrib/gcc/doc/rtl.texi
@@ -0,0 +1,3401 @@
+@c Copyright (C) 1988, 1989, 1992, 1994, 1997, 1998, 1999, 2000, 2001, 2002
+@c Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node RTL
+@chapter RTL Representation
+@cindex RTL representation
+@cindex representation of RTL
+@cindex Register Transfer Language (RTL)
+
+Most of the work of the compiler is done on an intermediate representation
+called register transfer language.  In this language, the instructions to be
+output are described, pretty much one by one, in an algebraic form that
+describes what the instruction does.
+
+RTL is inspired by Lisp lists.  It has both an internal form, made up of
+structures that point at other structures, and a textual form that is used
+in the machine description and in printed debugging dumps.  The textual
+form uses nested parentheses to indicate the pointers in the internal form.
+
+@menu
+* RTL Objects::       Expressions vs vectors vs strings vs integers.
+* RTL Classes::       Categories of RTL expression objects, and their structure.
+* Accessors::         Macros to access expression operands or vector elts.
+* Flags::             Other flags in an RTL expression.
+* Machine Modes::     Describing the size and format of a datum.
+* Constants::         Expressions with constant values.
+* Regs and Memory::   Expressions representing register contents or memory.
+* Arithmetic::        Expressions representing arithmetic on other expressions.
+* Comparisons::       Expressions representing comparison of expressions.
+* Bit-Fields::        Expressions representing bit-fields in memory or reg.
+* Vector Operations:: Expressions involving vector datatypes.
+* Conversions::       Extending, truncating, floating or fixing.
+* RTL Declarations::  Declaring volatility, constancy, etc.
+* Side Effects::      Expressions for storing in registers, etc.
+* Incdec::            Embedded side-effects for autoincrement addressing.
+* Assembler::         Representing @code{asm} with operands.
+* Insns::             Expression types for entire insns.
+* Calls::             RTL representation of function call insns.
+* Sharing::           Some expressions are unique; others *must* be copied.
+* Reading RTL::       Reading textual RTL from a file.
+@end menu
+
+@node RTL Objects
+@section RTL Object Types
+@cindex RTL object types
+
+@cindex RTL integers
+@cindex RTL strings
+@cindex RTL vectors
+@cindex RTL expression
+@cindex RTX (See RTL)
+RTL uses five kinds of objects: expressions, integers, wide integers,
+strings and vectors.  Expressions are the most important ones.  An RTL
+expression (``RTX'', for short) is a C structure, but it is usually
+referred to with a pointer; a type that is given the typedef name
+@code{rtx}.
+
+An integer is simply an @code{int}; their written form uses decimal
+digits.  A wide integer is an integral object whose type is
+@code{HOST_WIDE_INT}; their written form uses decimal digits.
+
+A string is a sequence of characters.  In core it is represented as a
+@code{char *} in usual C fashion, and it is written in C syntax as well.
+However, strings in RTL may never be null.  If you write an empty string in
+a machine description, it is represented in core as a null pointer rather
+than as a pointer to a null character.  In certain contexts, these null
+pointers instead of strings are valid.  Within RTL code, strings are most
+commonly found inside @code{symbol_ref} expressions, but they appear in
+other contexts in the RTL expressions that make up machine descriptions.
+
+In a machine description, strings are normally written with double
+quotes, as you would in C.  However, strings in machine descriptions may
+extend over many lines, which is invalid C, and adjacent string
+constants are not concatenated as they are in C.  Any string constant
+may be surrounded with a single set of parentheses.  Sometimes this
+makes the machine description easier to read.
+
+There is also a special syntax for strings, which can be useful when C
+code is embedded in a machine description.  Wherever a string can
+appear, it is also valid to write a C-style brace block.  The entire
+brace block, including the outermost pair of braces, is considered to be
+the string constant.  Double quote characters inside the braces are not
+special.  Therefore, if you write string constants in the C code, you
+need not escape each quote character with a backslash.
+
+A vector contains an arbitrary number of pointers to expressions.  The
+number of elements in the vector is explicitly present in the vector.
+The written form of a vector consists of square brackets
+(@samp{[@dots{}]}) surrounding the elements, in sequence and with
+whitespace separating them.  Vectors of length zero are not created;
+null pointers are used instead.
+
+@cindex expression codes
+@cindex codes, RTL expression
+@findex GET_CODE
+@findex PUT_CODE
+Expressions are classified by @dfn{expression codes} (also called RTX
+codes).  The expression code is a name defined in @file{rtl.def}, which is
+also (in upper case) a C enumeration constant.  The possible expression
+codes and their meanings are machine-independent.  The code of an RTX can
+be extracted with the macro @code{GET_CODE (@var{x})} and altered with
+@code{PUT_CODE (@var{x}, @var{newcode})}.
+
+The expression code determines how many operands the expression contains,
+and what kinds of objects they are.  In RTL, unlike Lisp, you cannot tell
+by looking at an operand what kind of object it is.  Instead, you must know
+from its context---from the expression code of the containing expression.
+For example, in an expression of code @code{subreg}, the first operand is
+to be regarded as an expression and the second operand as an integer.  In
+an expression of code @code{plus}, there are two operands, both of which
+are to be regarded as expressions.  In a @code{symbol_ref} expression,
+there is one operand, which is to be regarded as a string.
+
+Expressions are written as parentheses containing the name of the
+expression type, its flags and machine mode if any, and then the operands
+of the expression (separated by spaces).
+
+Expression code names in the @samp{md} file are written in lower case,
+but when they appear in C code they are written in upper case.  In this
+manual, they are shown as follows: @code{const_int}.
+
+@cindex (nil)
+@cindex nil
+In a few contexts a null pointer is valid where an expression is normally
+wanted.  The written form of this is @code{(nil)}.
+
+@node RTL Classes
+@section RTL Classes and Formats
+@cindex RTL classes
+@cindex classes of RTX codes
+@cindex RTX codes, classes of
+@findex GET_RTX_CLASS
+
+The various expression codes are divided into several @dfn{classes},
+which are represented by single characters.  You can determine the class
+of an RTX code with the macro @code{GET_RTX_CLASS (@var{code})}.
+Currently, @file{rtx.def} defines these classes:
+
+@table @code
+@item o
+An RTX code that represents an actual object, such as a register
+(@code{REG}) or a memory location (@code{MEM}, @code{SYMBOL_REF}).
+Constants and basic transforms on objects (@code{ADDRESSOF},
+@code{HIGH}, @code{LO_SUM}) are also included.  Note that @code{SUBREG}
+and @code{STRICT_LOW_PART} are not in this class, but in class @code{x}.
+
+@item <
+An RTX code for a comparison, such as @code{NE} or @code{LT}.
+
+@item 1
+An RTX code for a unary arithmetic operation, such as @code{NEG},
+@code{NOT}, or @code{ABS}.  This category also includes value extension
+(sign or zero) and conversions between integer and floating point.
+
+@item c
+An RTX code for a commutative binary operation, such as @code{PLUS} or
+@code{AND}.  @code{NE} and @code{EQ} are comparisons, so they have class
+@code{<}.
+
+@item 2
+An RTX code for a non-commutative binary operation, such as @code{MINUS},
+@code{DIV}, or @code{ASHIFTRT}.
+
+@item b
+An RTX code for a bit-field operation.  Currently only
+@code{ZERO_EXTRACT} and @code{SIGN_EXTRACT}.  These have three inputs
+and are lvalues (so they can be used for insertion as well).
+@xref{Bit-Fields}.
+
+@item 3
+An RTX code for other three input operations.  Currently only
+@code{IF_THEN_ELSE}.
+
+@item i
+An RTX code for an entire instruction:  @code{INSN}, @code{JUMP_INSN}, and
+@code{CALL_INSN}.  @xref{Insns}.
+
+@item m
+An RTX code for something that matches in insns, such as
+@code{MATCH_DUP}.  These only occur in machine descriptions.
+
+@item a
+An RTX code for an auto-increment addressing mode, such as
+@code{POST_INC}.
+
+@item x
+All other RTX codes.  This category includes the remaining codes used
+only in machine descriptions (@code{DEFINE_*}, etc.).  It also includes
+all the codes describing side effects (@code{SET}, @code{USE},
+@code{CLOBBER}, etc.) and the non-insns that may appear on an insn
+chain, such as @code{NOTE}, @code{BARRIER}, and @code{CODE_LABEL}.
+@end table
+
+@cindex RTL format
+For each expression code, @file{rtl.def} specifies the number of
+contained objects and their kinds using a sequence of characters
+called the @dfn{format} of the expression code.  For example,
+the format of @code{subreg} is @samp{ei}.
+
+@cindex RTL format characters
+These are the most commonly used format characters:
+
+@table @code
+@item e
+An expression (actually a pointer to an expression).
+
+@item i
+An integer.
+
+@item w
+A wide integer.
+
+@item s
+A string.
+
+@item E
+A vector of expressions.
+@end table
+
+A few other format characters are used occasionally:
+
+@table @code
+@item u
+@samp{u} is equivalent to @samp{e} except that it is printed differently
+in debugging dumps.  It is used for pointers to insns.
+
+@item n
+@samp{n} is equivalent to @samp{i} except that it is printed differently
+in debugging dumps.  It is used for the line number or code number of a
+@code{note} insn.
+
+@item S
+@samp{S} indicates a string which is optional.  In the RTL objects in
+core, @samp{S} is equivalent to @samp{s}, but when the object is read,
+from an @samp{md} file, the string value of this operand may be omitted.
+An omitted string is taken to be the null string.
+
+@item V
+@samp{V} indicates a vector which is optional.  In the RTL objects in
+core, @samp{V} is equivalent to @samp{E}, but when the object is read
+from an @samp{md} file, the vector value of this operand may be omitted.
+An omitted vector is effectively the same as a vector of no elements.
+
+@item 0
+@samp{0} means a slot whose contents do not fit any normal category.
+@samp{0} slots are not printed at all in dumps, and are often used in
+special ways by small parts of the compiler.
+@end table
+
+There are macros to get the number of operands and the format
+of an expression code:
+
+@table @code
+@findex GET_RTX_LENGTH
+@item GET_RTX_LENGTH (@var{code})
+Number of operands of an RTX of code @var{code}.
+
+@findex GET_RTX_FORMAT
+@item GET_RTX_FORMAT (@var{code})
+The format of an RTX of code @var{code}, as a C string.
+@end table
+
+Some classes of RTX codes always have the same format.  For example, it
+is safe to assume that all comparison operations have format @code{ee}.
+
+@table @code
+@item 1
+All codes of this class have format @code{e}.
+
+@item <
+@itemx c
+@itemx 2
+All codes of these classes have format @code{ee}.
+
+@item b
+@itemx 3
+All codes of these classes have format @code{eee}.
+
+@item i
+All codes of this class have formats that begin with @code{iuueiee}.
+@xref{Insns}.  Note that not all RTL objects linked onto an insn chain
+are of class @code{i}.
+
+@item o
+@itemx m
+@itemx x
+You can make no assumptions about the format of these codes.
+@end table
+
+@node Accessors
+@section Access to Operands
+@cindex accessors
+@cindex access to operands
+@cindex operand access
+
+@findex XEXP
+@findex XINT
+@findex XWINT
+@findex XSTR
+Operands of expressions are accessed using the macros @code{XEXP},
+@code{XINT}, @code{XWINT} and @code{XSTR}.  Each of these macros takes
+two arguments: an expression-pointer (RTX) and an operand number
+(counting from zero).  Thus,
+
+@example
+XEXP (@var{x}, 2)
+@end example
+
+@noindent
+accesses operand 2 of expression @var{x}, as an expression.
+
+@example
+XINT (@var{x}, 2)
+@end example
+
+@noindent
+accesses the same operand as an integer.  @code{XSTR}, used in the same
+fashion, would access it as a string.
+
+Any operand can be accessed as an integer, as an expression or as a string.
+You must choose the correct method of access for the kind of value actually
+stored in the operand.  You would do this based on the expression code of
+the containing expression.  That is also how you would know how many
+operands there are.
+
+For example, if @var{x} is a @code{subreg} expression, you know that it has
+two operands which can be correctly accessed as @code{XEXP (@var{x}, 0)}
+and @code{XINT (@var{x}, 1)}.  If you did @code{XINT (@var{x}, 0)}, you
+would get the address of the expression operand but cast as an integer;
+that might occasionally be useful, but it would be cleaner to write
+@code{(int) XEXP (@var{x}, 0)}.  @code{XEXP (@var{x}, 1)} would also
+compile without error, and would return the second, integer operand cast as
+an expression pointer, which would probably result in a crash when
+accessed.  Nothing stops you from writing @code{XEXP (@var{x}, 28)} either,
+but this will access memory past the end of the expression with
+unpredictable results.
+
+Access to operands which are vectors is more complicated.  You can use the
+macro @code{XVEC} to get the vector-pointer itself, or the macros
+@code{XVECEXP} and @code{XVECLEN} to access the elements and length of a
+vector.
+
+@table @code
+@findex XVEC
+@item XVEC (@var{exp}, @var{idx})
+Access the vector-pointer which is operand number @var{idx} in @var{exp}.
+
+@findex XVECLEN
+@item XVECLEN (@var{exp}, @var{idx})
+Access the length (number of elements) in the vector which is
+in operand number @var{idx} in @var{exp}.  This value is an @code{int}.
+
+@findex XVECEXP
+@item XVECEXP (@var{exp}, @var{idx}, @var{eltnum})
+Access element number @var{eltnum} in the vector which is
+in operand number @var{idx} in @var{exp}.  This value is an RTX@.
+
+It is up to you to make sure that @var{eltnum} is not negative
+and is less than @code{XVECLEN (@var{exp}, @var{idx})}.
+@end table
+
+All the macros defined in this section expand into lvalues and therefore
+can be used to assign the operands, lengths and vector elements as well as
+to access them.
+
+@node Flags
+@section Flags in an RTL Expression
+@cindex flags in RTL expression
+
+RTL expressions contain several flags (one-bit bit-fields)
+that are used in certain types of expression.  Most often they
+are accessed with the following macros, which expand into lvalues:
+
+@table @code
+@findex CONSTANT_POOL_ADDRESS_P
+@cindex @code{symbol_ref} and @samp{/u}
+@cindex @code{unchanging}, in @code{symbol_ref}
+@item CONSTANT_POOL_ADDRESS_P (@var{x})
+Nonzero in a @code{symbol_ref} if it refers to part of the current
+function's constant pool.  For most targets these addresses are in a
+@code{.rodata} section entirely separate from the function, but for
+some targets the addresses are close to the beginning of the function.
+In either case GCC assumes these addresses can be addressed directly,
+perhaps with the help of base registers.
+Stored in the @code{unchanging} field and printed as @samp{/u}.
+
+@findex CONST_OR_PURE_CALL_P
+@cindex @code{call_insn} and @samp{/u}
+@cindex @code{unchanging}, in @code{call_insn}
+@item CONST_OR_PURE_CALL_P (@var{x})
+In a @code{call_insn}, @code{note}, or an @code{expr_list} for notes,
+indicates that the insn represents a call to a const or pure function.
+Stored in the @code{unchanging} field and printed as @samp{/u}.
+
+@findex INSN_ANNULLED_BRANCH_P
+@cindex @code{insn} and @samp{/u}
+@cindex @code{unchanging}, in @code{insn}
+@item INSN_ANNULLED_BRANCH_P (@var{x})
+In an @code{insn} in the delay slot of a branch insn, indicates that an
+annulling branch should be used.  See the discussion under
+@code{sequence} below.  Stored in the @code{unchanging} field and printed
+as @samp{/u}.
+
+@findex INSN_DEAD_CODE_P
+@cindex @code{insn} and @samp{/s}
+@cindex @code{in_struct}, in @code{insn}
+@item INSN_DEAD_CODE_P (@var{x})
+In an @code{insn} during the dead-code elimination pass, nonzero if the
+insn is dead.
+Stored in the @code{in_struct} field and printed as @samp{/s}.
+
+@findex INSN_DELETED_P
+@cindex @code{insn} and @samp{/v}
+@cindex @code{volatil}, in @code{insn}
+@item INSN_DELETED_P (@var{x})
+In an @code{insn}, nonzero if the insn has been deleted.  Stored in the
+@code{volatil} field and printed as @samp{/v}.
+
+@findex INSN_FROM_TARGET_P
+@cindex @code{insn} and @samp{/s}
+@cindex @code{in_struct}, in @code{insn}
+@item INSN_FROM_TARGET_P (@var{x})
+In an @code{insn} in a delay slot of a branch, indicates that the insn
+is from the target of the branch.  If the branch insn has
+@code{INSN_ANNULLED_BRANCH_P} set, this insn will only be executed if
+the branch is taken.  For annulled branches with
+@code{INSN_FROM_TARGET_P} clear, the insn will be executed only if the
+branch is not taken.  When @code{INSN_ANNULLED_BRANCH_P} is not set,
+this insn will always be executed.  Stored in the @code{in_struct}
+field and printed as @samp{/s}.
+
+@findex LABEL_OUTSIDE_LOOP_P
+@cindex @code{label_ref} and @samp{/s}
+@cindex @code{in_struct}, in @code{label_ref}
+@item LABEL_OUTSIDE_LOOP_P (@var{x})
+In @code{label_ref} expressions, nonzero if this is a reference to a
+label that is outside the innermost loop containing the reference to the
+label.  Stored in the @code{in_struct} field and printed as @samp{/s}.
+
+@findex LABEL_PRESERVE_P
+@cindex @code{code_label} and @samp{/i}
+@cindex @code{in_struct}, in @code{code_label}
+@item LABEL_PRESERVE_P (@var{x})
+In a @code{code_label}, indicates that the label is referenced by
+code or data not visible to the RTL of a given function.
+Labels referenced by a non-local goto will have this bit set.  Stored
+in the @code{in_struct} field and printed as @samp{/s}.
+
+@findex LABEL_REF_NONLOCAL_P
+@cindex @code{label_ref} and @samp{/v}
+@cindex @code{volatil}, in @code{label_ref}
+@item LABEL_REF_NONLOCAL_P (@var{x})
+In @code{label_ref} and @code{reg_label} expressions, nonzero if this is
+a reference to a non-local label.
+Stored in the @code{volatil} field and printed as @samp{/v}.
+
+@findex LINK_COST_FREE
+@cindex @code{insn_list} and @samp{/c}
+@cindex @code{call}, in @code{insn_list}
+@item LINK_COST_FREE (@var{x})
+In the @code{LOG_LINKS} @code{insn_list} during scheduling, nonzero when
+the cost of executing an instruction through the link is zero, i.e., the
+link makes the cost free.  Stored in the @code{call} field and printed
+as @samp{/c}.
+
+@findex LINK_COST_ZERO
+@cindex @code{insn_list} and @samp{/j}
+@cindex @code{jump}, in @code{insn_list}
+@item LINK_COST_ZERO (@var{x})
+In the @code{LOG_LINKS} @code{insn_list} during scheduling, nonzero when
+the cost of executing an instruction through the link varies and is
+unchanged, i.e., the link has zero additional cost.
+Stored in the @code{jump} field and printed as @samp{/j}.
+
+@findex MEM_IN_STRUCT_P
+@cindex @code{mem} and @samp{/s}
+@cindex @code{in_struct}, in @code{mem}
+@item MEM_IN_STRUCT_P (@var{x})
+In @code{mem} expressions, nonzero for reference to an entire structure,
+union or array, or to a component of one.  Zero for references to a
+scalar variable or through a pointer to a scalar.  If both this flag and
+@code{MEM_SCALAR_P} are clear, then we don't know whether this @code{mem}
+is in a structure or not.  Both flags should never be simultaneously set.
+Stored in the @code{in_struct} field and printed as @samp{/s}.
+
+@findex MEM_KEEP_ALIAS_SET_P
+@cindex @code{mem} and @samp{/j}
+@cindex @code{jump}, in @code{mem}
+@item MEM_KEEP_ALIAS_SET_P (@var{x})
+In @code{mem} expressions, 1 if we should keep the alias set for this
+mem unchanged when we access a component.  Set to 1, for example, when we
+are already in a non-addressable component of an aggregate.
+Stored in the @code{jump} field and printed as @samp{/j}.
+
+@findex MEM_SCALAR_P
+@cindex @code{mem} and @samp{/f}
+@cindex @code{frame_related}, in @code{mem}
+@item MEM_SCALAR_P (@var{x})
+In @code{mem} expressions, nonzero for reference to a scalar known not
+to be a member of a structure, union, or array.  Zero for such
+references and for indirections through pointers, even pointers pointing
+to scalar types.  If both this flag and @code{MEM_STRUCT_P} are clear, then we
+don't know whether this @code{mem} is in a structure or not.  Both flags should
+never be simultaneously set.
+Stored in the @code{frame_related} field and printed as @samp{/f}.
+
+@findex MEM_VOLATILE_P
+@cindex @code{mem} and @samp{/v}
+@cindex @code{volatil}, in @code{mem}
+@item MEM_VOLATILE_P (@var{x})
+In @code{mem} and @code{asm_operands} expressions, nonzero for volatile
+memory references.
+Stored in the @code{volatil} field and printed as @samp{/v}.
+
+@findex REG_FUNCTION_VALUE_P
+@cindex @code{reg} and @samp{/i}
+@cindex @code{integrated}, in @code{reg}
+@item REG_FUNCTION_VALUE_P (@var{x})
+Nonzero in a @code{reg} if it is the place in which this function's
+value is going to be returned.  (This happens only in a hard
+register.)  Stored in the @code{integrated} field and printed as
+@samp{/i}.
+
+@findex REG_LOOP_TEST_P
+@cindex @code{reg} and @samp{/s}
+@cindex @code{in_struct}, in @code{reg}
+@item REG_LOOP_TEST_P (@var{x})
+In @code{reg} expressions, nonzero if this register's entire life is
+contained in the exit test code for some loop.  Stored in the
+@code{in_struct} field and printed as @samp{/s}.
+
+@findex REG_POINTER
+@cindex @code{reg} and @samp{/f}
+@cindex @code{frame_related}, in @code{reg}
+@item REG_POINTER (@var{x})
+Nonzero in a @code{reg} if the register holds a pointer.  Stored in the
+@code{frame_related} field and printed as @samp{/f}.
+
+@findex REG_USERVAR_P
+@cindex @code{reg} and @samp{/v}
+@cindex @code{volatil}, in @code{reg}
+@item REG_USERVAR_P (@var{x})
+In a @code{reg}, nonzero if it corresponds to a variable present in
+the user's source code.  Zero for temporaries generated internally by
+the compiler.  Stored in the @code{volatil} field and printed as
+@samp{/v}.
+
+The same hard register may be used also for collecting the values of
+functions called by this one, but @code{REG_FUNCTION_VALUE_P} is zero
+in this kind of use.
+
+@findex RTX_FRAME_RELATED_P
+@cindex @code{insn} and @samp{/f}
+@cindex @code{frame_related}, in @code{insn}
+@item RTX_FRAME_RELATED_P (@var{x})
+Nonzero in an @code{insn} or @code{set} which is part of a function prologue
+and sets the stack pointer, sets the frame pointer, or saves a register.
+This flag should also be set on an instruction that sets up a temporary
+register to use in place of the frame pointer.
+Stored in the @code{frame_related} field and printed as @samp{/f}.
+
+In particular, on RISC targets where there are limits on the sizes of
+immediate constants, it is sometimes impossible to reach the register
+save area directly from the stack pointer.  In that case, a temporary
+register is used that is near enough to the register save area, and the
+Canonical Frame Address, i.e., DWARF2's logical frame pointer, register
+must (temporarily) be changed to be this temporary register.  So, the
+instruction that sets this temporary register must be marked as
+@code{RTX_FRAME_RELATED_P}.
+
+If the marked instruction is overly complex (defined in terms of what
+@code{dwarf2out_frame_debug_expr} can handle), you will also have to
+create a @code{REG_FRAME_RELATED_EXPR} note and attach it to the
+instruction.  This note should contain a simple expression of the
+computation performed by this instruction, i.e., one that
+@code{dwarf2out_frame_debug_expr} can handle.
+
+This flag is required for exception handling support on targets with RTL
+prologues.
+
+@findex RTX_INTEGRATED_P
+@cindex @code{insn} and @samp{/i}
+@cindex @code{integrated}, in @code{insn}
+@item RTX_INTEGRATED_P (@var{x})
+Nonzero in an @code{insn}, @code{insn_list}, or @code{const} if it
+resulted from an in-line function call.
+Stored in the @code{integrated} field and printed as @samp{/i}.
+
+@findex RTX_UNCHANGING_P
+@cindex @code{reg} and @samp{/u}
+@cindex @code{mem} and @samp{/u}
+@cindex @code{unchanging}, in @code{reg} and @code{mem}
+@item RTX_UNCHANGING_P (@var{x})
+Nonzero in a @code{reg} or @code{mem} if the memory is set at most once,
+anywhere.  This does not mean that it is function invariant.
+Stored in the @code{unchanging} field and printed as @samp{/u}.
+
+@findex SCHED_GROUP_P
+@cindex @code{insn} and @samp{/i}
+@cindex @code{in_struct}, in @code{insn}
+@item SCHED_GROUP_P (@var{x})
+During instruction scheduling, in an @code{insn}, indicates that the
+previous insn must be scheduled together with this insn.  This is used to
+ensure that certain groups of instructions will not be split up by the
+instruction scheduling pass, for example, @code{use} insns before
+a @code{call_insn} may not be separated from the @code{call_insn}.
+Stored in the @code{in_struct} field and printed as @samp{/s}.
+
+@findex SET_IS_RETURN_P
+@cindex @code{insn} and @samp{/j}
+@cindex @code{jump}, in @code{insn}
+@item SET_IS_RETURN_P (@var{x})
+For a @code{set}, nonzero if it is for a return.
+Stored in the @code{jump} field and printed as @samp{/j}.
+
+@findex SIBLING_CALL_P
+@cindex @code{call_insn} and @samp{/j}
+@cindex @code{jump}, in @code{call_insn}
+@item SIBLING_CALL_P (@var{x})
+For a @code{call_insn}, nonzero if the insn is a sibling call.
+Stored in the @code{jump} field and printed as @samp{/j}.
+
+@findex STRING_POOL_ADDRESS_P
+@cindex @code{symbol_ref} and @samp{/f}
+@cindex @code{frame_related}, in @code{symbol_ref}
+@item STRING_POOL_ADDRESS_P (@var{x})
+For a @code{symbol_ref} expression, nonzero if it addresses this function's
+string constant pool.
+Stored in the @code{frame_related} field and printed as @samp{/f}.
+
+@findex SUBREG_PROMOTED_UNSIGNED_P
+@cindex @code{subreg} and @samp{/u}
+@cindex @code{unchanging}, in @code{subreg}
+@item SUBREG_PROMOTED_UNSIGNED_P (@var{x})
+Nonzero in a @code{subreg} that has @code{SUBREG_PROMOTED_VAR_P} nonzero
+if the object being referenced is kept zero-extended and zero if it
+is kept sign-extended.  Stored in the @code{unchanging} field and
+printed as @samp{/u}.
+
+@findex SUBREG_PROMOTED_VAR_P
+@cindex @code{subreg} and @samp{/s}
+@cindex @code{in_struct}, in @code{subreg}
+@item SUBREG_PROMOTED_VAR_P (@var{x})
+Nonzero in a @code{subreg} if it was made when accessing an object that
+was promoted to a wider mode in accord with the @code{PROMOTED_MODE} machine
+description macro (@pxref{Storage Layout}).  In this case, the mode of
+the @code{subreg} is the declared mode of the object and the mode of
+@code{SUBREG_REG} is the mode of the register that holds the object.
+Promoted variables are always either sign- or zero-extended to the wider
+mode on every assignment.  Stored in the @code{in_struct} field and
+printed as @samp{/s}.
+
+@findex SYMBOL_REF_FLAG
+@cindex @code{symbol_ref} and @samp{/v}
+@cindex @code{volatil}, in @code{symbol_ref}
+@item SYMBOL_REF_FLAG (@var{x})
+In a @code{symbol_ref}, this is used as a flag for machine-specific purposes.
+Stored in the @code{volatil} field and printed as @samp{/v}.
+
+@findex SYMBOL_REF_USED
+@cindex @code{used}, in @code{symbol_ref}
+@item SYMBOL_REF_USED (@var{x})
+In a @code{symbol_ref}, indicates that @var{x} has been used.  This is
+normally only used to ensure that @var{x} is only declared external
+once.  Stored in the @code{used} field.
+
+@findex SYMBOL_REF_WEAK
+@cindex @code{symbol_ref} and @samp{/i}
+@cindex @code{integrated}, in @code{symbol_ref}
+@item SYMBOL_REF_WEAK (@var{x})
+In a @code{symbol_ref}, indicates that @var{x} has been declared weak.
+Stored in the @code{integrated} field and printed as @samp{/i}.
+@end table
+
+These are the fields to which the above macros refer:
+
+@table @code
+@findex call
+@cindex @samp{/c} in RTL dump
+@item call
+In the @code{LOG_LINKS} of an @code{insn_list} during scheduling, 1 means that
+the cost of executing an instruction through the link is zero.
+
+In an RTL dump, this flag is represented as @samp{/c}.
+
+@findex frame_related
+@cindex @samp{/f} in RTL dump
+@item frame_related
+In an @code{insn} or @code{set} expression, 1 means that it is part of
+a function prologue and sets the stack pointer, sets the frame pointer,
+saves a register, or sets up a temporary register to use in place of the
+frame pointer.
+
+In @code{reg} expressions, 1 means that the register holds a pointer.
+
+In @code{symbol_ref} expressions, 1 means that the reference addresses
+this function's string constant pool.
+
+In @code{mem} expressions, 1 means that the reference is to a scalar.
+
+In an RTL dump, this flag is represented as @samp{/f}.
+
+@findex in_struct
+@cindex @samp{/s} in RTL dump
+@item in_struct
+In @code{mem} expressions, it is 1 if the memory datum referred to is
+all or part of a structure or array; 0 if it is (or might be) a scalar
+variable.  A reference through a C pointer has 0 because the pointer
+might point to a scalar variable.  This information allows the compiler
+to determine something about possible cases of aliasing.
+
+In @code{reg} expressions, it is 1 if the register has its entire life
+contained within the test expression of some loop.
+
+In @code{subreg} expressions, 1 means that the @code{subreg} is accessing
+an object that has had its mode promoted from a wider mode.
+
+In @code{label_ref} expressions, 1 means that the referenced label is
+outside the innermost loop containing the insn in which the @code{label_ref}
+was found.
+
+In @code{code_label} expressions, it is 1 if the label may never be deleted.
+This is used for labels which are the target of non-local gotos.  Such a
+label that would have been deleted is replaced with a @code{note} of type
+@code{NOTE_INSN_DELETED_LABEL}.
+
+In an @code{insn} during dead-code elimination, 1 means that the insn is
+dead code.
+
+In an @code{insn} during reorg for an insn in the delay slot of a branch,
+1 means that this insn is from the target of the branch.
+
+In an @code{insn} during instruction scheduling, 1 means that this insn
+must be scheduled as part of a group together with the previous insn.
+
+In an RTL dump, this flag is represented as @samp{/s}.
+
+@findex integrated
+@cindex @samp{/i} in RTL dump
+@item integrated
+In an @code{insn}, @code{insn_list}, or @code{const}, 1 means the RTL was
+produced by procedure integration.
+
+In @code{reg} expressions, 1 means the register contains
+the value to be returned by the current function.  On
+machines that pass parameters in registers, the same register number
+may be used for parameters as well, but this flag is not set on such
+uses.
+
+In @code{symbol_ref} expressions, 1 means the referenced symbol is weak.
+
+In an RTL dump, this flag is represented as @samp{/i}.
+
+@findex jump
+@cindex @samp{/j} in RTL dump
+@item jump
+In a @code{mem} expression, 1 means we should keep the alias set for this
+mem unchanged when we access a component.
+
+In a @code{set}, 1 means it is for a return.
+
+In a @code{call_insn}, 1 means it is a sibling call.
+
+In the @code{LOG_LINKS} of an @code{insn_list} during scheduling, 1 means the
+cost of executing an instruction through the link varies and is unchanging.
+
+In an RTL dump, this flag is represented as @samp{/j}.
+
+@findex unchanging
+@cindex @samp{/u} in RTL dump
+@item unchanging
+In @code{reg} and @code{mem} expressions, 1 means
+that the value of the expression never changes.
+
+In @code{subreg} expressions, it is 1 if the @code{subreg} references an
+unsigned object whose mode has been promoted to a wider mode.
+
+In an @code{insn}, 1 means that this is an annulling branch.
+
+In a @code{symbol_ref} expression, 1 means that this symbol addresses
+something in the per-function constant pool.
+
+In a @code{call_insn}, @code{note}, or an @code{expr_list} of notes,
+1 means that this instruction is a call to a const or pure function.
+
+In an RTL dump, this flag is represented as @samp{/u}.
+
+@findex used
+@item used
+This flag is used directly (without an access macro) at the end of RTL
+generation for a function, to count the number of times an expression
+appears in insns.  Expressions that appear more than once are copied,
+according to the rules for shared structure (@pxref{Sharing}).
+
+For a @code{reg}, it is used directly (without an access macro) by the
+leaf register renumbering code to ensure that each register is only
+renumbered once.
+
+In a @code{symbol_ref}, it indicates that an external declaration for
+the symbol has already been written.
+
+@findex volatil
+@cindex @samp{/v} in RTL dump
+@item volatil
+@cindex volatile memory references
+In a @code{mem} or @code{asm_operands} expression, it is 1 if the memory
+reference is volatile.  Volatile memory references may not be deleted,
+reordered or combined.
+
+In a @code{symbol_ref} expression, it is used for machine-specific
+purposes.
+
+In a @code{reg} expression, it is 1 if the value is a user-level variable.
+0 indicates an internal compiler temporary.
+
+In an @code{insn}, 1 means the insn has been deleted.
+
+In @code{label_ref} and @code{reg_label} expressions, 1 means a reference
+to a non-local label.
+
+In an RTL dump, this flag is represented as @samp{/v}.
+@end table
+
+@node Machine Modes
+@section Machine Modes
+@cindex machine modes
+
+@findex enum machine_mode
+A machine mode describes a size of data object and the representation used
+for it.  In the C code, machine modes are represented by an enumeration
+type, @code{enum machine_mode}, defined in @file{machmode.def}.  Each RTL
+expression has room for a machine mode and so do certain kinds of tree
+expressions (declarations and types, to be precise).
+
+In debugging dumps and machine descriptions, the machine mode of an RTL
+expression is written after the expression code with a colon to separate
+them.  The letters @samp{mode} which appear at the end of each machine mode
+name are omitted.  For example, @code{(reg:SI 38)} is a @code{reg}
+expression with machine mode @code{SImode}.  If the mode is
+@code{VOIDmode}, it is not written at all.
+
+Here is a table of machine modes.  The term ``byte'' below refers to an
+object of @code{BITS_PER_UNIT} bits (@pxref{Storage Layout}).
+
+@table @code
+@findex BImode
+@item BImode
+``Bit'' mode represents a single bit, for predicate registers.
+
+@findex QImode
+@item QImode
+``Quarter-Integer'' mode represents a single byte treated as an integer.
+
+@findex HImode
+@item HImode
+``Half-Integer'' mode represents a two-byte integer.
+
+@findex PSImode
+@item PSImode
+``Partial Single Integer'' mode represents an integer which occupies
+four bytes but which doesn't really use all four.  On some machines,
+this is the right mode to use for pointers.
+
+@findex SImode
+@item SImode
+``Single Integer'' mode represents a four-byte integer.
+
+@findex PDImode
+@item PDImode
+``Partial Double Integer'' mode represents an integer which occupies
+eight bytes but which doesn't really use all eight.  On some machines,
+this is the right mode to use for certain pointers.
+
+@findex DImode
+@item DImode
+``Double Integer'' mode represents an eight-byte integer.
+
+@findex TImode
+@item TImode
+``Tetra Integer'' (?) mode represents a sixteen-byte integer.
+
+@findex OImode
+@item OImode
+``Octa Integer'' (?) mode represents a thirty-two-byte integer.
+
+@findex QFmode
+@item QFmode
+``Quarter-Floating'' mode represents a quarter-precision (single byte)
+floating point number.
+
+@findex HFmode
+@item HFmode
+``Half-Floating'' mode represents a half-precision (two byte) floating
+point number.
+
+@findex TQFmode
+@item TQFmode
+``Three-Quarter-Floating'' (?) mode represents a three-quarter-precision
+(three byte) floating point number.
+
+@findex SFmode
+@item SFmode
+``Single Floating'' mode represents a four byte floating point number.
+In the common case, of a processor with IEEE arithmetic and 8-bit bytes,
+this is a single-precision IEEE floating point number; it can also be
+used for double-precision (on processors with 16-bit bytes) and
+single-precision VAX and IBM types.
+
+@findex DFmode
+@item DFmode
+``Double Floating'' mode represents an eight byte floating point number.
+In the common case, of a processor with IEEE arithmetic and 8-bit bytes,
+this is a double-precision IEEE floating point number.
+
+@findex XFmode
+@item XFmode
+``Extended Floating'' mode represents a twelve byte floating point
+number.  This mode is used for IEEE extended floating point.  On some
+systems not all bits within these bytes will actually be used.
+
+@findex TFmode
+@item TFmode
+``Tetra Floating'' mode represents a sixteen byte floating point number.
+This gets used for both the 96-bit extended IEEE floating-point types
+padded to 128 bits, and true 128-bit extended IEEE floating-point types.
+
+@findex CCmode
+@item CCmode
+``Condition Code'' mode represents the value of a condition code, which
+is a machine-specific set of bits used to represent the result of a
+comparison operation.  Other machine-specific modes may also be used for
+the condition code.  These modes are not used on machines that use
+@code{cc0} (see @pxref{Condition Code}).
+
+@findex BLKmode
+@item BLKmode
+``Block'' mode represents values that are aggregates to which none of
+the other modes apply.  In RTL, only memory references can have this mode,
+and only if they appear in string-move or vector instructions.  On machines
+which have no such instructions, @code{BLKmode} will not appear in RTL@.
+
+@findex VOIDmode
+@item VOIDmode
+Void mode means the absence of a mode or an unspecified mode.
+For example, RTL expressions of code @code{const_int} have mode
+@code{VOIDmode} because they can be taken to have whatever mode the context
+requires.  In debugging dumps of RTL, @code{VOIDmode} is expressed by
+the absence of any mode.
+
+@findex QCmode
+@findex HCmode
+@findex SCmode
+@findex DCmode
+@findex XCmode
+@findex TCmode
+@item QCmode, HCmode, SCmode, DCmode, XCmode, TCmode
+These modes stand for a complex number represented as a pair of floating
+point values.  The floating point values are in @code{QFmode},
+@code{HFmode}, @code{SFmode}, @code{DFmode}, @code{XFmode}, and
+@code{TFmode}, respectively.
+
+@findex CQImode
+@findex CHImode
+@findex CSImode
+@findex CDImode
+@findex CTImode
+@findex COImode
+@item CQImode, CHImode, CSImode, CDImode, CTImode, COImode
+These modes stand for a complex number represented as a pair of integer
+values.  The integer values are in @code{QImode}, @code{HImode},
+@code{SImode}, @code{DImode}, @code{TImode}, and @code{OImode},
+respectively.
+@end table
+
+The machine description defines @code{Pmode} as a C macro which expands
+into the machine mode used for addresses.  Normally this is the mode
+whose size is @code{BITS_PER_WORD}, @code{SImode} on 32-bit machines.
+
+The only modes which a machine description @i{must} support are
+@code{QImode}, and the modes corresponding to @code{BITS_PER_WORD},
+@code{FLOAT_TYPE_SIZE} and @code{DOUBLE_TYPE_SIZE}.
+The compiler will attempt to use @code{DImode} for 8-byte structures and
+unions, but this can be prevented by overriding the definition of
+@code{MAX_FIXED_MODE_SIZE}.  Alternatively, you can have the compiler
+use @code{TImode} for 16-byte structures and unions.  Likewise, you can
+arrange for the C type @code{short int} to avoid using @code{HImode}.
+
+@cindex mode classes
+Very few explicit references to machine modes remain in the compiler and
+these few references will soon be removed.  Instead, the machine modes
+are divided into mode classes.  These are represented by the enumeration
+type @code{enum mode_class} defined in @file{machmode.h}.  The possible
+mode classes are:
+
+@table @code
+@findex MODE_INT
+@item MODE_INT
+Integer modes.  By default these are @code{BImode}, @code{QImode},
+@code{HImode}, @code{SImode}, @code{DImode}, @code{TImode}, and
+@code{OImode}.
+
+@findex MODE_PARTIAL_INT
+@item MODE_PARTIAL_INT
+The ``partial integer'' modes, @code{PQImode}, @code{PHImode},
+@code{PSImode} and @code{PDImode}.
+
+@findex MODE_FLOAT
+@item MODE_FLOAT
+Floating point modes.  By default these are @code{QFmode},
+@code{HFmode}, @code{TQFmode}, @code{SFmode}, @code{DFmode},
+@code{XFmode} and @code{TFmode}.
+
+@findex MODE_COMPLEX_INT
+@item MODE_COMPLEX_INT
+Complex integer modes.  (These are not currently implemented).
+
+@findex MODE_COMPLEX_FLOAT
+@item MODE_COMPLEX_FLOAT
+Complex floating point modes.  By default these are @code{QCmode},
+@code{HCmode}, @code{SCmode}, @code{DCmode}, @code{XCmode}, and
+@code{TCmode}.
+
+@findex MODE_FUNCTION
+@item MODE_FUNCTION
+Algol or Pascal function variables including a static chain.
+(These are not currently implemented).
+
+@findex MODE_CC
+@item MODE_CC
+Modes representing condition code values.  These are @code{CCmode} plus
+any modes listed in the @code{EXTRA_CC_MODES} macro.  @xref{Jump Patterns},
+also see @ref{Condition Code}.
+
+@findex MODE_RANDOM
+@item MODE_RANDOM
+This is a catchall mode class for modes which don't fit into the above
+classes.  Currently @code{VOIDmode} and @code{BLKmode} are in
+@code{MODE_RANDOM}.
+@end table
+
+Here are some C macros that relate to machine modes:
+
+@table @code
+@findex GET_MODE
+@item GET_MODE (@var{x})
+Returns the machine mode of the RTX @var{x}.
+
+@findex PUT_MODE
+@item PUT_MODE (@var{x}, @var{newmode})
+Alters the machine mode of the RTX @var{x} to be @var{newmode}.
+
+@findex NUM_MACHINE_MODES
+@item NUM_MACHINE_MODES
+Stands for the number of machine modes available on the target
+machine.  This is one greater than the largest numeric value of any
+machine mode.
+
+@findex GET_MODE_NAME
+@item GET_MODE_NAME (@var{m})
+Returns the name of mode @var{m} as a string.
+
+@findex GET_MODE_CLASS
+@item GET_MODE_CLASS (@var{m})
+Returns the mode class of mode @var{m}.
+
+@findex GET_MODE_WIDER_MODE
+@item GET_MODE_WIDER_MODE (@var{m})
+Returns the next wider natural mode.  For example, the expression
+@code{GET_MODE_WIDER_MODE (QImode)} returns @code{HImode}.
+
+@findex GET_MODE_SIZE
+@item GET_MODE_SIZE (@var{m})
+Returns the size in bytes of a datum of mode @var{m}.
+
+@findex GET_MODE_BITSIZE
+@item GET_MODE_BITSIZE (@var{m})
+Returns the size in bits of a datum of mode @var{m}.
+
+@findex GET_MODE_MASK
+@item GET_MODE_MASK (@var{m})
+Returns a bitmask containing 1 for all bits in a word that fit within
+mode @var{m}.  This macro can only be used for modes whose bitsize is
+less than or equal to @code{HOST_BITS_PER_INT}.
+
+@findex GET_MODE_ALIGNMENT
+@item GET_MODE_ALIGNMENT (@var{m})
+Return the required alignment, in bits, for an object of mode @var{m}.
+
+@findex GET_MODE_UNIT_SIZE
+@item GET_MODE_UNIT_SIZE (@var{m})
+Returns the size in bytes of the subunits of a datum of mode @var{m}.
+This is the same as @code{GET_MODE_SIZE} except in the case of complex
+modes.  For them, the unit size is the size of the real or imaginary
+part.
+
+@findex GET_MODE_NUNITS
+@item GET_MODE_NUNITS (@var{m})
+Returns the number of units contained in a mode, i.e.,
+@code{GET_MODE_SIZE} divided by @code{GET_MODE_UNIT_SIZE}.
+
+@findex GET_CLASS_NARROWEST_MODE
+@item GET_CLASS_NARROWEST_MODE (@var{c})
+Returns the narrowest mode in mode class @var{c}.
+@end table
+
+@findex byte_mode
+@findex word_mode
+The global variables @code{byte_mode} and @code{word_mode} contain modes
+whose classes are @code{MODE_INT} and whose bitsizes are either
+@code{BITS_PER_UNIT} or @code{BITS_PER_WORD}, respectively.  On 32-bit
+machines, these are @code{QImode} and @code{SImode}, respectively.
+
+@node Constants
+@section Constant Expression Types
+@cindex RTL constants
+@cindex RTL constant expression types
+
+The simplest RTL expressions are those that represent constant values.
+
+@table @code
+@findex const_int
+@item (const_int @var{i})
+This type of expression represents the integer value @var{i}.  @var{i}
+is customarily accessed with the macro @code{INTVAL} as in
+@code{INTVAL (@var{exp})}, which is equivalent to @code{XWINT (@var{exp}, 0)}.
+
+@findex const0_rtx
+@findex const1_rtx
+@findex const2_rtx
+@findex constm1_rtx
+There is only one expression object for the integer value zero; it is
+the value of the variable @code{const0_rtx}.  Likewise, the only
+expression for integer value one is found in @code{const1_rtx}, the only
+expression for integer value two is found in @code{const2_rtx}, and the
+only expression for integer value negative one is found in
+@code{constm1_rtx}.  Any attempt to create an expression of code
+@code{const_int} and value zero, one, two or negative one will return
+@code{const0_rtx}, @code{const1_rtx}, @code{const2_rtx} or
+@code{constm1_rtx} as appropriate.
+
+@findex const_true_rtx
+Similarly, there is only one object for the integer whose value is
+@code{STORE_FLAG_VALUE}.  It is found in @code{const_true_rtx}.  If
+@code{STORE_FLAG_VALUE} is one, @code{const_true_rtx} and
+@code{const1_rtx} will point to the same object.  If
+@code{STORE_FLAG_VALUE} is @minus{}1, @code{const_true_rtx} and
+@code{constm1_rtx} will point to the same object.
+
+@findex const_double
+@item (const_double:@var{m} @var{addr} @var{i0} @var{i1} @dots{})
+Represents either a floating-point constant of mode @var{m} or an
+integer constant too large to fit into @code{HOST_BITS_PER_WIDE_INT}
+bits but small enough to fit within twice that number of bits (GCC
+does not provide a mechanism to represent even larger constants).  In
+the latter case, @var{m} will be @code{VOIDmode}.
+
+@findex CONST_DOUBLE_MEM
+@findex CONST_DOUBLE_CHAIN
+@var{addr} is used to contain the @code{mem} expression that corresponds
+to the location in memory that at which the constant can be found.  If
+it has not been allocated a memory location, but is on the chain of all
+@code{const_double} expressions in this compilation (maintained using an
+undisplayed field), @var{addr} contains @code{const0_rtx}.  If it is not
+on the chain, @var{addr} contains @code{cc0_rtx}.  @var{addr} is
+customarily accessed with the macro @code{CONST_DOUBLE_MEM} and the
+chain field via @code{CONST_DOUBLE_CHAIN}.
+
+@findex CONST_DOUBLE_LOW
+If @var{m} is @code{VOIDmode}, the bits of the value are stored in
+@var{i0} and @var{i1}.  @var{i0} is customarily accessed with the macro
+@code{CONST_DOUBLE_LOW} and @var{i1} with @code{CONST_DOUBLE_HIGH}.
+
+If the constant is floating point (regardless of its precision), then
+the number of integers used to store the value depends on the size of
+@code{REAL_VALUE_TYPE} (@pxref{Cross-compilation}).  The integers
+represent a floating point number, but not precisely in the target
+machine's or host machine's floating point format.  To convert them to
+the precise bit pattern used by the target machine, use the macro
+@code{REAL_VALUE_TO_TARGET_DOUBLE} and friends (@pxref{Data Output}).
+
+@findex CONST0_RTX
+@findex CONST1_RTX
+@findex CONST2_RTX
+The macro @code{CONST0_RTX (@var{mode})} refers to an expression with
+value 0 in mode @var{mode}.  If mode @var{mode} is of mode class
+@code{MODE_INT}, it returns @code{const0_rtx}.  Otherwise, it returns a
+@code{CONST_DOUBLE} expression in mode @var{mode}.  Similarly, the macro
+@code{CONST1_RTX (@var{mode})} refers to an expression with value 1 in
+mode @var{mode} and similarly for @code{CONST2_RTX}.
+
+@findex const_string
+@item (const_string @var{str})
+Represents a constant string with value @var{str}.  Currently this is
+used only for insn attributes (@pxref{Insn Attributes}) since constant
+strings in C are placed in memory.
+
+@findex symbol_ref
+@item (symbol_ref:@var{mode} @var{symbol})
+Represents the value of an assembler label for data.  @var{symbol} is
+a string that describes the name of the assembler label.  If it starts
+with a @samp{*}, the label is the rest of @var{symbol} not including
+the @samp{*}.  Otherwise, the label is @var{symbol}, usually prefixed
+with @samp{_}.
+
+The @code{symbol_ref} contains a mode, which is usually @code{Pmode}.
+Usually that is the only mode for which a symbol is directly valid.
+
+@findex label_ref
+@item (label_ref @var{label})
+Represents the value of an assembler label for code.  It contains one
+operand, an expression, which must be a @code{code_label} or a @code{note}
+of type @code{NOTE_INSN_DELETED_LABEL} that appears in the instruction
+sequence to identify the place where the label should go.
+
+The reason for using a distinct expression type for code label
+references is so that jump optimization can distinguish them.
+
+@item (const:@var{m} @var{exp})
+Represents a constant that is the result of an assembly-time
+arithmetic computation.  The operand, @var{exp}, is an expression that
+contains only constants (@code{const_int}, @code{symbol_ref} and
+@code{label_ref} expressions) combined with @code{plus} and
+@code{minus}.  However, not all combinations are valid, since the
+assembler cannot do arbitrary arithmetic on relocatable symbols.
+
+@var{m} should be @code{Pmode}.
+
+@findex high
+@item (high:@var{m} @var{exp})
+Represents the high-order bits of @var{exp}, usually a
+@code{symbol_ref}.  The number of bits is machine-dependent and is
+normally the number of bits specified in an instruction that initializes
+the high order bits of a register.  It is used with @code{lo_sum} to
+represent the typical two-instruction sequence used in RISC machines to
+reference a global memory location.
+
+@var{m} should be @code{Pmode}.
+@end table
+
+@node Regs and Memory
+@section Registers and Memory
+@cindex RTL register expressions
+@cindex RTL memory expressions
+
+Here are the RTL expression types for describing access to machine
+registers and to main memory.
+
+@table @code
+@findex reg
+@cindex hard registers
+@cindex pseudo registers
+@item (reg:@var{m} @var{n})
+For small values of the integer @var{n} (those that are less than
+@code{FIRST_PSEUDO_REGISTER}), this stands for a reference to machine
+register number @var{n}: a @dfn{hard register}.  For larger values of
+@var{n}, it stands for a temporary value or @dfn{pseudo register}.
+The compiler's strategy is to generate code assuming an unlimited
+number of such pseudo registers, and later convert them into hard
+registers or into memory references.
+
+@var{m} is the machine mode of the reference.  It is necessary because
+machines can generally refer to each register in more than one mode.
+For example, a register may contain a full word but there may be
+instructions to refer to it as a half word or as a single byte, as
+well as instructions to refer to it as a floating point number of
+various precisions.
+
+Even for a register that the machine can access in only one mode,
+the mode must always be specified.
+
+The symbol @code{FIRST_PSEUDO_REGISTER} is defined by the machine
+description, since the number of hard registers on the machine is an
+invariant characteristic of the machine.  Note, however, that not
+all of the machine registers must be general registers.  All the
+machine registers that can be used for storage of data are given
+hard register numbers, even those that can be used only in certain
+instructions or can hold only certain types of data.
+
+A hard register may be accessed in various modes throughout one
+function, but each pseudo register is given a natural mode
+and is accessed only in that mode.  When it is necessary to describe
+an access to a pseudo register using a nonnatural mode, a @code{subreg}
+expression is used.
+
+A @code{reg} expression with a machine mode that specifies more than
+one word of data may actually stand for several consecutive registers.
+If in addition the register number specifies a hardware register, then
+it actually represents several consecutive hardware registers starting
+with the specified one.
+
+Each pseudo register number used in a function's RTL code is
+represented by a unique @code{reg} expression.
+
+@findex FIRST_VIRTUAL_REGISTER
+@findex LAST_VIRTUAL_REGISTER
+Some pseudo register numbers, those within the range of
+@code{FIRST_VIRTUAL_REGISTER} to @code{LAST_VIRTUAL_REGISTER} only
+appear during the RTL generation phase and are eliminated before the
+optimization phases.  These represent locations in the stack frame that
+cannot be determined until RTL generation for the function has been
+completed.  The following virtual register numbers are defined:
+
+@table @code
+@findex VIRTUAL_INCOMING_ARGS_REGNUM
+@item VIRTUAL_INCOMING_ARGS_REGNUM
+This points to the first word of the incoming arguments passed on the
+stack.  Normally these arguments are placed there by the caller, but the
+callee may have pushed some arguments that were previously passed in
+registers.
+
+@cindex @code{FIRST_PARM_OFFSET} and virtual registers
+@cindex @code{ARG_POINTER_REGNUM} and virtual registers
+When RTL generation is complete, this virtual register is replaced
+by the sum of the register given by @code{ARG_POINTER_REGNUM} and the
+value of @code{FIRST_PARM_OFFSET}.
+
+@findex VIRTUAL_STACK_VARS_REGNUM
+@cindex @code{FRAME_GROWS_DOWNWARD} and virtual registers
+@item VIRTUAL_STACK_VARS_REGNUM
+If @code{FRAME_GROWS_DOWNWARD} is defined, this points to immediately
+above the first variable on the stack.  Otherwise, it points to the
+first variable on the stack.
+
+@cindex @code{STARTING_FRAME_OFFSET} and virtual registers
+@cindex @code{FRAME_POINTER_REGNUM} and virtual registers
+@code{VIRTUAL_STACK_VARS_REGNUM} is replaced with the sum of the
+register given by @code{FRAME_POINTER_REGNUM} and the value
+@code{STARTING_FRAME_OFFSET}.
+
+@findex VIRTUAL_STACK_DYNAMIC_REGNUM
+@item VIRTUAL_STACK_DYNAMIC_REGNUM
+This points to the location of dynamically allocated memory on the stack
+immediately after the stack pointer has been adjusted by the amount of
+memory desired.
+
+@cindex @code{STACK_DYNAMIC_OFFSET} and virtual registers
+@cindex @code{STACK_POINTER_REGNUM} and virtual registers
+This virtual register is replaced by the sum of the register given by
+@code{STACK_POINTER_REGNUM} and the value @code{STACK_DYNAMIC_OFFSET}.
+
+@findex VIRTUAL_OUTGOING_ARGS_REGNUM
+@item VIRTUAL_OUTGOING_ARGS_REGNUM
+This points to the location in the stack at which outgoing arguments
+should be written when the stack is pre-pushed (arguments pushed using
+push insns should always use @code{STACK_POINTER_REGNUM}).
+
+@cindex @code{STACK_POINTER_OFFSET} and virtual registers
+This virtual register is replaced by the sum of the register given by
+@code{STACK_POINTER_REGNUM} and the value @code{STACK_POINTER_OFFSET}.
+@end table
+
+@findex subreg
+@item (subreg:@var{m} @var{reg} @var{bytenum})
+@code{subreg} expressions are used to refer to a register in a machine
+mode other than its natural one, or to refer to one register of
+a multi-part @code{reg} that actually refers to several registers.
+
+Each pseudo-register has a natural mode.  If it is necessary to
+operate on it in a different mode---for example, to perform a fullword
+move instruction on a pseudo-register that contains a single
+byte---the pseudo-register must be enclosed in a @code{subreg}.  In
+such a case, @var{bytenum} is zero.
+
+Usually @var{m} is at least as narrow as the mode of @var{reg}, in which
+case it is restricting consideration to only the bits of @var{reg} that
+are in @var{m}.
+
+Sometimes @var{m} is wider than the mode of @var{reg}.  These
+@code{subreg} expressions are often called @dfn{paradoxical}.  They are
+used in cases where we want to refer to an object in a wider mode but do
+not care what value the additional bits have.  The reload pass ensures
+that paradoxical references are only made to hard registers.
+
+The other use of @code{subreg} is to extract the individual registers of
+a multi-register value.  Machine modes such as @code{DImode} and
+@code{TImode} can indicate values longer than a word, values which
+usually require two or more consecutive registers.  To access one of the
+registers, use a @code{subreg} with mode @code{SImode} and a
+@var{bytenum} offset that says which register.
+
+Storing in a non-paradoxical @code{subreg} has undefined results for
+bits belonging to the same word as the @code{subreg}.  This laxity makes
+it easier to generate efficient code for such instructions.  To
+represent an instruction that preserves all the bits outside of those in
+the @code{subreg}, use @code{strict_low_part} around the @code{subreg}.
+
+@cindex @code{WORDS_BIG_ENDIAN}, effect on @code{subreg}
+The compilation parameter @code{WORDS_BIG_ENDIAN}, if set to 1, says
+that byte number zero is part of the most significant word; otherwise,
+it is part of the least significant word.
+
+@cindex @code{BYTES_BIG_ENDIAN}, effect on @code{subreg}
+The compilation parameter @code{BYTES_BIG_ENDIAN}, if set to 1, says
+that byte number zero is the most significant byte within a word;
+otherwise, it is the least significant byte within a word.
+
+@cindex @code{FLOAT_WORDS_BIG_ENDIAN}, (lack of) effect on @code{subreg}
+On a few targets, @code{FLOAT_WORDS_BIG_ENDIAN} disagrees with
+@code{WORDS_BIG_ENDIAN}.
+However, most parts of the compiler treat floating point values as if
+they had the same endianness as integer values.  This works because
+they handle them solely as a collection of integer values, with no
+particular numerical value.  Only real.c and the runtime libraries
+care about @code{FLOAT_WORDS_BIG_ENDIAN}.
+
+@cindex combiner pass
+@cindex reload pass
+@cindex @code{subreg}, special reload handling
+Between the combiner pass and the reload pass, it is possible to have a
+paradoxical @code{subreg} which contains a @code{mem} instead of a
+@code{reg} as its first operand.  After the reload pass, it is also
+possible to have a non-paradoxical @code{subreg} which contains a
+@code{mem}; this usually occurs when the @code{mem} is a stack slot
+which replaced a pseudo register.
+
+Note that it is not valid to access a @code{DFmode} value in @code{SFmode}
+using a @code{subreg}.  On some machines the most significant part of a
+@code{DFmode} value does not have the same format as a single-precision
+floating value.
+
+It is also not valid to access a single word of a multi-word value in a
+hard register when less registers can hold the value than would be
+expected from its size.  For example, some 32-bit machines have
+floating-point registers that can hold an entire @code{DFmode} value.
+If register 10 were such a register @code{(subreg:SI (reg:DF 10) 1)}
+would be invalid because there is no way to convert that reference to
+a single machine register.  The reload pass prevents @code{subreg}
+expressions such as these from being formed.
+
+@findex SUBREG_REG
+@findex SUBREG_BYTE
+The first operand of a @code{subreg} expression is customarily accessed
+with the @code{SUBREG_REG} macro and the second operand is customarily
+accessed with the @code{SUBREG_BYTE} macro.
+
+@findex scratch
+@cindex scratch operands
+@item (scratch:@var{m})
+This represents a scratch register that will be required for the
+execution of a single instruction and not used subsequently.  It is
+converted into a @code{reg} by either the local register allocator or
+the reload pass.
+
+@code{scratch} is usually present inside a @code{clobber} operation
+(@pxref{Side Effects}).
+
+@findex cc0
+@cindex condition code register
+@item (cc0)
+This refers to the machine's condition code register.  It has no
+operands and may not have a machine mode.  There are two ways to use it:
+
+@itemize @bullet
+@item
+To stand for a complete set of condition code flags.  This is best on
+most machines, where each comparison sets the entire series of flags.
+
+With this technique, @code{(cc0)} may be validly used in only two
+contexts: as the destination of an assignment (in test and compare
+instructions) and in comparison operators comparing against zero
+(@code{const_int} with value zero; that is to say, @code{const0_rtx}).
+
+@item
+To stand for a single flag that is the result of a single condition.
+This is useful on machines that have only a single flag bit, and in
+which comparison instructions must specify the condition to test.
+
+With this technique, @code{(cc0)} may be validly used in only two
+contexts: as the destination of an assignment (in test and compare
+instructions) where the source is a comparison operator, and as the
+first operand of @code{if_then_else} (in a conditional branch).
+@end itemize
+
+@findex cc0_rtx
+There is only one expression object of code @code{cc0}; it is the
+value of the variable @code{cc0_rtx}.  Any attempt to create an
+expression of code @code{cc0} will return @code{cc0_rtx}.
+
+Instructions can set the condition code implicitly.  On many machines,
+nearly all instructions set the condition code based on the value that
+they compute or store.  It is not necessary to record these actions
+explicitly in the RTL because the machine description includes a
+prescription for recognizing the instructions that do so (by means of
+the macro @code{NOTICE_UPDATE_CC}).  @xref{Condition Code}.  Only
+instructions whose sole purpose is to set the condition code, and
+instructions that use the condition code, need mention @code{(cc0)}.
+
+On some machines, the condition code register is given a register number
+and a @code{reg} is used instead of @code{(cc0)}.  This is usually the
+preferable approach if only a small subset of instructions modify the
+condition code.  Other machines store condition codes in general
+registers; in such cases a pseudo register should be used.
+
+Some machines, such as the Sparc and RS/6000, have two sets of
+arithmetic instructions, one that sets and one that does not set the
+condition code.  This is best handled by normally generating the
+instruction that does not set the condition code, and making a pattern
+that both performs the arithmetic and sets the condition code register
+(which would not be @code{(cc0)} in this case).  For examples, search
+for @samp{addcc} and @samp{andcc} in @file{sparc.md}.
+
+@findex pc
+@item (pc)
+@cindex program counter
+This represents the machine's program counter.  It has no operands and
+may not have a machine mode.  @code{(pc)} may be validly used only in
+certain specific contexts in jump instructions.
+
+@findex pc_rtx
+There is only one expression object of code @code{pc}; it is the value
+of the variable @code{pc_rtx}.  Any attempt to create an expression of
+code @code{pc} will return @code{pc_rtx}.
+
+All instructions that do not jump alter the program counter implicitly
+by incrementing it, but there is no need to mention this in the RTL@.
+
+@findex mem
+@item (mem:@var{m} @var{addr} @var{alias})
+This RTX represents a reference to main memory at an address
+represented by the expression @var{addr}.  @var{m} specifies how large
+a unit of memory is accessed.  @var{alias} specifies an alias set for the
+reference.  In general two items are in different alias sets if they cannot
+reference the same memory address.
+
+@findex addressof
+@item (addressof:@var{m} @var{reg})
+This RTX represents a request for the address of register @var{reg}.  Its mode
+is always @code{Pmode}.  If there are any @code{addressof}
+expressions left in the function after CSE, @var{reg} is forced into the
+stack and the @code{addressof} expression is replaced with a @code{plus}
+expression for the address of its stack slot.
+@end table
+
+@node Arithmetic
+@section RTL Expressions for Arithmetic
+@cindex arithmetic, in RTL
+@cindex math, in RTL
+@cindex RTL expressions for arithmetic
+
+Unless otherwise specified, all the operands of arithmetic expressions
+must be valid for mode @var{m}.  An operand is valid for mode @var{m}
+if it has mode @var{m}, or if it is a @code{const_int} or
+@code{const_double} and @var{m} is a mode of class @code{MODE_INT}.
+
+For commutative binary operations, constants should be placed in the
+second operand.
+
+@table @code
+@findex plus
+@cindex RTL addition
+@cindex RTL sum
+@item (plus:@var{m} @var{x} @var{y})
+Represents the sum of the values represented by @var{x} and @var{y}
+carried out in machine mode @var{m}.
+
+@findex lo_sum
+@item (lo_sum:@var{m} @var{x} @var{y})
+Like @code{plus}, except that it represents that sum of @var{x} and the
+low-order bits of @var{y}.  The number of low order bits is
+machine-dependent but is normally the number of bits in a @code{Pmode}
+item minus the number of bits set by the @code{high} code
+(@pxref{Constants}).
+
+@var{m} should be @code{Pmode}.
+
+@findex minus
+@cindex RTL subtraction
+@cindex RTL difference
+@item (minus:@var{m} @var{x} @var{y})
+Like @code{plus} but represents subtraction.
+
+@findex ss_plus
+@cindex RTL addition with signed saturation
+@item (ss_plus:@var{m} @var{x} @var{y})
+
+Like @code{plus}, but using signed saturation in case of an overflow.
+
+@findex us_plus
+@cindex RTL addition with unsigned saturation
+@item (us_plus:@var{m} @var{x} @var{y})
+
+Like @code{plus}, but using unsigned saturation in case of an overflow.
+
+@findex ss_minus
+@cindex RTL addition with signed saturation
+@item (ss_minus:@var{m} @var{x} @var{y})
+
+Like @code{minus}, but using signed saturation in case of an overflow.
+
+@findex us_minus
+@cindex RTL addition with unsigned saturation
+@item (us_minus:@var{m} @var{x} @var{y})
+
+Like @code{minus}, but using unsigned saturation in case of an overflow.
+
+@findex compare
+@cindex RTL comparison
+@item (compare:@var{m} @var{x} @var{y})
+Represents the result of subtracting @var{y} from @var{x} for purposes
+of comparison.  The result is computed without overflow, as if with
+infinite precision.
+
+Of course, machines can't really subtract with infinite precision.
+However, they can pretend to do so when only the sign of the result will
+be used, which is the case when the result is stored in the condition
+code.  And that is the @emph{only} way this kind of expression may
+validly be used: as a value to be stored in the condition codes, either
+@code{(cc0)} or a register.  @xref{Comparisons}.
+
+The mode @var{m} is not related to the modes of @var{x} and @var{y}, but
+instead is the mode of the condition code value.  If @code{(cc0)} is
+used, it is @code{VOIDmode}.  Otherwise it is some mode in class
+@code{MODE_CC}, often @code{CCmode}.  @xref{Condition Code}.  If @var{m}
+is @code{VOIDmode} or @code{CCmode}, the operation returns sufficient
+information (in an unspecified format) so that any comparison operator
+can be applied to the result of the @code{COMPARE} operation.  For other
+modes in class @code{MODE_CC}, the operation only returns a subset of
+this information.
+
+Normally, @var{x} and @var{y} must have the same mode.  Otherwise,
+@code{compare} is valid only if the mode of @var{x} is in class
+@code{MODE_INT} and @var{y} is a @code{const_int} or
+@code{const_double} with mode @code{VOIDmode}.  The mode of @var{x}
+determines what mode the comparison is to be done in; thus it must not
+be @code{VOIDmode}.
+
+If one of the operands is a constant, it should be placed in the
+second operand and the comparison code adjusted as appropriate.
+
+A @code{compare} specifying two @code{VOIDmode} constants is not valid
+since there is no way to know in what mode the comparison is to be
+performed; the comparison must either be folded during the compilation
+or the first operand must be loaded into a register while its mode is
+still known.
+
+@findex neg
+@item (neg:@var{m} @var{x})
+Represents the negation (subtraction from zero) of the value represented
+by @var{x}, carried out in mode @var{m}.
+
+@findex mult
+@cindex multiplication
+@cindex product
+@item (mult:@var{m} @var{x} @var{y})
+Represents the signed product of the values represented by @var{x} and
+@var{y} carried out in machine mode @var{m}.
+
+Some machines support a multiplication that generates a product wider
+than the operands.  Write the pattern for this as
+
+@example
+(mult:@var{m} (sign_extend:@var{m} @var{x}) (sign_extend:@var{m} @var{y}))
+@end example
+
+where @var{m} is wider than the modes of @var{x} and @var{y}, which need
+not be the same.
+
+For unsigned widening multiplication, use the same idiom, but with
+@code{zero_extend} instead of @code{sign_extend}.
+
+@findex div
+@cindex division
+@cindex signed division
+@cindex quotient
+@item (div:@var{m} @var{x} @var{y})
+Represents the quotient in signed division of @var{x} by @var{y},
+carried out in machine mode @var{m}.  If @var{m} is a floating point
+mode, it represents the exact quotient; otherwise, the integerized
+quotient.
+
+Some machines have division instructions in which the operands and
+quotient widths are not all the same; you should represent
+such instructions using @code{truncate} and @code{sign_extend} as in,
+
+@example
+(truncate:@var{m1} (div:@var{m2} @var{x} (sign_extend:@var{m2} @var{y})))
+@end example
+
+@findex udiv
+@cindex unsigned division
+@cindex division
+@item (udiv:@var{m} @var{x} @var{y})
+Like @code{div} but represents unsigned division.
+
+@findex mod
+@findex umod
+@cindex remainder
+@cindex division
+@item (mod:@var{m} @var{x} @var{y})
+@itemx (umod:@var{m} @var{x} @var{y})
+Like @code{div} and @code{udiv} but represent the remainder instead of
+the quotient.
+
+@findex smin
+@findex smax
+@cindex signed minimum
+@cindex signed maximum
+@item (smin:@var{m} @var{x} @var{y})
+@itemx (smax:@var{m} @var{x} @var{y})
+Represents the smaller (for @code{smin}) or larger (for @code{smax}) of
+@var{x} and @var{y}, interpreted as signed integers in mode @var{m}.
+
+@findex umin
+@findex umax
+@cindex unsigned minimum and maximum
+@item (umin:@var{m} @var{x} @var{y})
+@itemx (umax:@var{m} @var{x} @var{y})
+Like @code{smin} and @code{smax}, but the values are interpreted as unsigned
+integers.
+
+@findex not
+@cindex complement, bitwise
+@cindex bitwise complement
+@item (not:@var{m} @var{x})
+Represents the bitwise complement of the value represented by @var{x},
+carried out in mode @var{m}, which must be a fixed-point machine mode.
+
+@findex and
+@cindex logical-and, bitwise
+@cindex bitwise logical-and
+@item (and:@var{m} @var{x} @var{y})
+Represents the bitwise logical-and of the values represented by
+@var{x} and @var{y}, carried out in machine mode @var{m}, which must be
+a fixed-point machine mode.
+
+@findex ior
+@cindex inclusive-or, bitwise
+@cindex bitwise inclusive-or
+@item (ior:@var{m} @var{x} @var{y})
+Represents the bitwise inclusive-or of the values represented by @var{x}
+and @var{y}, carried out in machine mode @var{m}, which must be a
+fixed-point mode.
+
+@findex xor
+@cindex exclusive-or, bitwise
+@cindex bitwise exclusive-or
+@item (xor:@var{m} @var{x} @var{y})
+Represents the bitwise exclusive-or of the values represented by @var{x}
+and @var{y}, carried out in machine mode @var{m}, which must be a
+fixed-point mode.
+
+@findex ashift
+@cindex left shift
+@cindex shift
+@cindex arithmetic shift
+@item (ashift:@var{m} @var{x} @var{c})
+Represents the result of arithmetically shifting @var{x} left by @var{c}
+places.  @var{x} have mode @var{m}, a fixed-point machine mode.  @var{c}
+be a fixed-point mode or be a constant with mode @code{VOIDmode}; which
+mode is determined by the mode called for in the machine description
+entry for the left-shift instruction.  For example, on the VAX, the mode
+of @var{c} is @code{QImode} regardless of @var{m}.
+
+@findex lshiftrt
+@cindex right shift
+@findex ashiftrt
+@item (lshiftrt:@var{m} @var{x} @var{c})
+@itemx (ashiftrt:@var{m} @var{x} @var{c})
+Like @code{ashift} but for right shift.  Unlike the case for left shift,
+these two operations are distinct.
+
+@findex rotate
+@cindex rotate
+@cindex left rotate
+@findex rotatert
+@cindex right rotate
+@item (rotate:@var{m} @var{x} @var{c})
+@itemx (rotatert:@var{m} @var{x} @var{c})
+Similar but represent left and right rotate.  If @var{c} is a constant,
+use @code{rotate}.
+
+@findex abs
+@cindex absolute value
+@item (abs:@var{m} @var{x})
+Represents the absolute value of @var{x}, computed in mode @var{m}.
+
+@findex sqrt
+@cindex square root
+@item (sqrt:@var{m} @var{x})
+Represents the square root of @var{x}, computed in mode @var{m}.
+Most often @var{m} will be a floating point mode.
+
+@findex ffs
+@item (ffs:@var{m} @var{x})
+Represents one plus the index of the least significant 1-bit in
+@var{x}, represented as an integer of mode @var{m}.  (The value is
+zero if @var{x} is zero.)  The mode of @var{x} need not be @var{m};
+depending on the target machine, various mode combinations may be
+valid.
+@end table
+
+@node Comparisons
+@section Comparison Operations
+@cindex RTL comparison operations
+
+Comparison operators test a relation on two operands and are considered
+to represent a machine-dependent nonzero value described by, but not
+necessarily equal to, @code{STORE_FLAG_VALUE} (@pxref{Misc})
+if the relation holds, or zero if it does not.  The mode of the
+comparison operation is independent of the mode of the data being
+compared.  If the comparison operation is being tested (e.g., the first
+operand of an @code{if_then_else}), the mode must be @code{VOIDmode}.
+If the comparison operation is producing data to be stored in some
+variable, the mode must be in class @code{MODE_INT}.  All comparison
+operations producing data must use the same mode, which is
+machine-specific.
+
+@cindex condition codes
+There are two ways that comparison operations may be used.  The
+comparison operators may be used to compare the condition codes
+@code{(cc0)} against zero, as in @code{(eq (cc0) (const_int 0))}.  Such
+a construct actually refers to the result of the preceding instruction
+in which the condition codes were set.  The instruction setting the
+condition code must be adjacent to the instruction using the condition
+code; only @code{note} insns may separate them.
+
+Alternatively, a comparison operation may directly compare two data
+objects.  The mode of the comparison is determined by the operands; they
+must both be valid for a common machine mode.  A comparison with both
+operands constant would be invalid as the machine mode could not be
+deduced from it, but such a comparison should never exist in RTL due to
+constant folding.
+
+In the example above, if @code{(cc0)} were last set to
+@code{(compare @var{x} @var{y})}, the comparison operation is
+identical to @code{(eq @var{x} @var{y})}.  Usually only one style
+of comparisons is supported on a particular machine, but the combine
+pass will try to merge the operations to produce the @code{eq} shown
+in case it exists in the context of the particular insn involved.
+
+Inequality comparisons come in two flavors, signed and unsigned.  Thus,
+there are distinct expression codes @code{gt} and @code{gtu} for signed and
+unsigned greater-than.  These can produce different results for the same
+pair of integer values: for example, 1 is signed greater-than @minus{}1 but not
+unsigned greater-than, because @minus{}1 when regarded as unsigned is actually
+@code{0xffffffff} which is greater than 1.
+
+The signed comparisons are also used for floating point values.  Floating
+point comparisons are distinguished by the machine modes of the operands.
+
+@table @code
+@findex eq
+@cindex equal
+@item (eq:@var{m} @var{x} @var{y})
+@code{STORE_FLAG_VALUE} if the values represented by @var{x} and @var{y}
+are equal, otherwise 0.
+
+@findex ne
+@cindex not equal
+@item (ne:@var{m} @var{x} @var{y})
+@code{STORE_FLAG_VALUE} if the values represented by @var{x} and @var{y}
+are not equal, otherwise 0.
+
+@findex gt
+@cindex greater than
+@item (gt:@var{m} @var{x} @var{y})
+@code{STORE_FLAG_VALUE} if the @var{x} is greater than @var{y}.  If they
+are fixed-point, the comparison is done in a signed sense.
+
+@findex gtu
+@cindex greater than
+@cindex unsigned greater than
+@item (gtu:@var{m} @var{x} @var{y})
+Like @code{gt} but does unsigned comparison, on fixed-point numbers only.
+
+@findex lt
+@cindex less than
+@findex ltu
+@cindex unsigned less than
+@item (lt:@var{m} @var{x} @var{y})
+@itemx (ltu:@var{m} @var{x} @var{y})
+Like @code{gt} and @code{gtu} but test for ``less than''.
+
+@findex ge
+@cindex greater than
+@findex geu
+@cindex unsigned greater than
+@item (ge:@var{m} @var{x} @var{y})
+@itemx (geu:@var{m} @var{x} @var{y})
+Like @code{gt} and @code{gtu} but test for ``greater than or equal''.
+
+@findex le
+@cindex less than or equal
+@findex leu
+@cindex unsigned less than
+@item (le:@var{m} @var{x} @var{y})
+@itemx (leu:@var{m} @var{x} @var{y})
+Like @code{gt} and @code{gtu} but test for ``less than or equal''.
+
+@findex if_then_else
+@item (if_then_else @var{cond} @var{then} @var{else})
+This is not a comparison operation but is listed here because it is
+always used in conjunction with a comparison operation.  To be
+precise, @var{cond} is a comparison expression.  This expression
+represents a choice, according to @var{cond}, between the value
+represented by @var{then} and the one represented by @var{else}.
+
+On most machines, @code{if_then_else} expressions are valid only
+to express conditional jumps.
+
+@findex cond
+@item (cond [@var{test1} @var{value1} @var{test2} @var{value2} @dots{}] @var{default})
+Similar to @code{if_then_else}, but more general.  Each of @var{test1},
+@var{test2}, @dots{} is performed in turn.  The result of this expression is
+the @var{value} corresponding to the first nonzero test, or @var{default} if
+none of the tests are nonzero expressions.
+
+This is currently not valid for instruction patterns and is supported only
+for insn attributes.  @xref{Insn Attributes}.
+@end table
+
+@node Bit-Fields
+@section Bit-Fields
+@cindex bit-fields
+
+Special expression codes exist to represent bit-field instructions.
+These types of expressions are lvalues in RTL; they may appear
+on the left side of an assignment, indicating insertion of a value
+into the specified bit-field.
+
+@table @code
+@findex sign_extract
+@cindex @code{BITS_BIG_ENDIAN}, effect on @code{sign_extract}
+@item (sign_extract:@var{m} @var{loc} @var{size} @var{pos})
+This represents a reference to a sign-extended bit-field contained or
+starting in @var{loc} (a memory or register reference).  The bit-field
+is @var{size} bits wide and starts at bit @var{pos}.  The compilation
+option @code{BITS_BIG_ENDIAN} says which end of the memory unit
+@var{pos} counts from.
+
+If @var{loc} is in memory, its mode must be a single-byte integer mode.
+If @var{loc} is in a register, the mode to use is specified by the
+operand of the @code{insv} or @code{extv} pattern
+(@pxref{Standard Names}) and is usually a full-word integer mode,
+which is the default if none is specified.
+
+The mode of @var{pos} is machine-specific and is also specified
+in the @code{insv} or @code{extv} pattern.
+
+The mode @var{m} is the same as the mode that would be used for
+@var{loc} if it were a register.
+
+@findex zero_extract
+@item (zero_extract:@var{m} @var{loc} @var{size} @var{pos})
+Like @code{sign_extract} but refers to an unsigned or zero-extended
+bit-field.  The same sequence of bits are extracted, but they
+are filled to an entire word with zeros instead of by sign-extension.
+@end table
+
+@node Vector Operations
+@section Vector Operations
+@cindex vector operations
+
+All normal RTL expressions can be used with vector modes; they are
+interpreted as operating on each part of the vector independently.
+Additionally, there are a few new expressions to describe specific vector
+operations.
+
+@table @code
+@findex vec_merge
+@item (vec_merge:@var{m} @var{vec1} @var{vec2} @var{items})
+This describes a merge operation between two vectors.  The result is a vector
+of mode @var{m}; its elements are selected from either @var{vec1} or
+@var{vec2}.  Which elements are selected is described by @var{items}, which
+is a bit mask represented by a @code{const_int}; a zero bit indicates the
+corresponding element in the result vector is taken from @var{vec2} while
+a set bit indicates it is taken from @var{vec1}.
+
+@findex vec_select
+@item (vec_select:@var{m} @var{vec1} @var{selection})
+This describes an operation that selects parts of a vector.  @var{vec1} is
+the source vector, @var{selection} is a @code{parallel} that contains a
+@code{const_int} for each of the subparts of the result vector, giving the
+number of the source subpart that should be stored into it.
+
+@findex vec_concat
+@item (vec_concat:@var{m} @var{vec1} @var{vec2})
+Describes a vector concat operation.  The result is a concatenation of the
+vectors @var{vec1} and @var{vec2}; its length is the sum of the lengths of
+the two inputs.
+
+@findex vec_const
+@item (vec_const:@var{m} @var{subparts})
+This describes a constant vector.  @var{subparts} is a @code{parallel} that
+contains a constant for each of the subparts of the vector.
+
+@findex vec_duplicate
+@item (vec_duplicate:@var{m} @var{vec})
+This operation converts a small vector into a larger one by duplicating the
+input values.  The output vector mode must have the same submodes as the
+input vector mode, and the number of output parts must be an integer multiple
+of the number of input parts.
+
+@end table
+
+@node Conversions
+@section Conversions
+@cindex conversions
+@cindex machine mode conversions
+
+All conversions between machine modes must be represented by
+explicit conversion operations.  For example, an expression
+which is the sum of a byte and a full word cannot be written as
+@code{(plus:SI (reg:QI 34) (reg:SI 80))} because the @code{plus}
+operation requires two operands of the same machine mode.
+Therefore, the byte-sized operand is enclosed in a conversion
+operation, as in
+
+@example
+(plus:SI (sign_extend:SI (reg:QI 34)) (reg:SI 80))
+@end example
+
+The conversion operation is not a mere placeholder, because there
+may be more than one way of converting from a given starting mode
+to the desired final mode.  The conversion operation code says how
+to do it.
+
+For all conversion operations, @var{x} must not be @code{VOIDmode}
+because the mode in which to do the conversion would not be known.
+The conversion must either be done at compile-time or @var{x}
+must be placed into a register.
+
+@table @code
+@findex sign_extend
+@item (sign_extend:@var{m} @var{x})
+Represents the result of sign-extending the value @var{x}
+to machine mode @var{m}.  @var{m} must be a fixed-point mode
+and @var{x} a fixed-point value of a mode narrower than @var{m}.
+
+@findex zero_extend
+@item (zero_extend:@var{m} @var{x})
+Represents the result of zero-extending the value @var{x}
+to machine mode @var{m}.  @var{m} must be a fixed-point mode
+and @var{x} a fixed-point value of a mode narrower than @var{m}.
+
+@findex float_extend
+@item (float_extend:@var{m} @var{x})
+Represents the result of extending the value @var{x}
+to machine mode @var{m}.  @var{m} must be a floating point mode
+and @var{x} a floating point value of a mode narrower than @var{m}.
+
+@findex truncate
+@item (truncate:@var{m} @var{x})
+Represents the result of truncating the value @var{x}
+to machine mode @var{m}.  @var{m} must be a fixed-point mode
+and @var{x} a fixed-point value of a mode wider than @var{m}.
+
+@findex ss_truncate
+@item (ss_truncate:@var{m} @var{x})
+Represents the result of truncating the value @var{x}
+to machine mode @var{m}, using signed saturation in the case of
+overflow.  Both @var{m} and the mode of @var{x} must be fixed-point
+modes.
+
+@findex us_truncate
+@item (us_truncate:@var{m} @var{x})
+Represents the result of truncating the value @var{x}
+to machine mode @var{m}, using unsigned saturation in the case of
+overflow.  Both @var{m} and the mode of @var{x} must be fixed-point
+modes.
+
+@findex float_truncate
+@item (float_truncate:@var{m} @var{x})
+Represents the result of truncating the value @var{x}
+to machine mode @var{m}.  @var{m} must be a floating point mode
+and @var{x} a floating point value of a mode wider than @var{m}.
+
+@findex float
+@item (float:@var{m} @var{x})
+Represents the result of converting fixed point value @var{x},
+regarded as signed, to floating point mode @var{m}.
+
+@findex unsigned_float
+@item (unsigned_float:@var{m} @var{x})
+Represents the result of converting fixed point value @var{x},
+regarded as unsigned, to floating point mode @var{m}.
+
+@findex fix
+@item (fix:@var{m} @var{x})
+When @var{m} is a fixed point mode, represents the result of
+converting floating point value @var{x} to mode @var{m}, regarded as
+signed.  How rounding is done is not specified, so this operation may
+be used validly in compiling C code only for integer-valued operands.
+
+@findex unsigned_fix
+@item (unsigned_fix:@var{m} @var{x})
+Represents the result of converting floating point value @var{x} to
+fixed point mode @var{m}, regarded as unsigned.  How rounding is done
+is not specified.
+
+@findex fix
+@item (fix:@var{m} @var{x})
+When @var{m} is a floating point mode, represents the result of
+converting floating point value @var{x} (valid for mode @var{m}) to an
+integer, still represented in floating point mode @var{m}, by rounding
+towards zero.
+@end table
+
+@node RTL Declarations
+@section Declarations
+@cindex RTL declarations
+@cindex declarations, RTL
+
+Declaration expression codes do not represent arithmetic operations
+but rather state assertions about their operands.
+
+@table @code
+@findex strict_low_part
+@cindex @code{subreg}, in @code{strict_low_part}
+@item (strict_low_part (subreg:@var{m} (reg:@var{n} @var{r}) 0))
+This expression code is used in only one context: as the destination operand of a
+@code{set} expression.  In addition, the operand of this expression
+must be a non-paradoxical @code{subreg} expression.
+
+The presence of @code{strict_low_part} says that the part of the
+register which is meaningful in mode @var{n}, but is not part of
+mode @var{m}, is not to be altered.  Normally, an assignment to such
+a subreg is allowed to have undefined effects on the rest of the
+register when @var{m} is less than a word.
+@end table
+
+@node Side Effects
+@section Side Effect Expressions
+@cindex RTL side effect expressions
+
+The expression codes described so far represent values, not actions.
+But machine instructions never produce values; they are meaningful
+only for their side effects on the state of the machine.  Special
+expression codes are used to represent side effects.
+
+The body of an instruction is always one of these side effect codes;
+the codes described above, which represent values, appear only as
+the operands of these.
+
+@table @code
+@findex set
+@item (set @var{lval} @var{x})
+Represents the action of storing the value of @var{x} into the place
+represented by @var{lval}.  @var{lval} must be an expression
+representing a place that can be stored in: @code{reg} (or @code{subreg}
+or @code{strict_low_part}), @code{mem}, @code{pc}, @code{parallel}, or
+@code{cc0}.
+
+If @var{lval} is a @code{reg}, @code{subreg} or @code{mem}, it has a
+machine mode; then @var{x} must be valid for that mode.
+
+If @var{lval} is a @code{reg} whose machine mode is less than the full
+width of the register, then it means that the part of the register
+specified by the machine mode is given the specified value and the
+rest of the register receives an undefined value.  Likewise, if
+@var{lval} is a @code{subreg} whose machine mode is narrower than
+the mode of the register, the rest of the register can be changed in
+an undefined way.
+
+If @var{lval} is a @code{strict_low_part} of a @code{subreg}, then the
+part of the register specified by the machine mode of the
+@code{subreg} is given the value @var{x} and the rest of the register
+is not changed.
+
+If @var{lval} is @code{(cc0)}, it has no machine mode, and @var{x} may
+be either a @code{compare} expression or a value that may have any mode.
+The latter case represents a ``test'' instruction.  The expression
+@code{(set (cc0) (reg:@var{m} @var{n}))} is equivalent to
+@code{(set (cc0) (compare (reg:@var{m} @var{n}) (const_int 0)))}.
+Use the former expression to save space during the compilation.
+
+If @var{lval} is a @code{parallel}, it is used to represent the case of
+a function returning a structure in multiple registers.  Each element
+of the @code{parallel} is an @code{expr_list} whose first operand is a
+@code{reg} and whose second operand is a @code{const_int} representing the
+offset (in bytes) into the structure at which the data in that register
+corresponds.  The first element may be null to indicate that the structure
+is also passed partly in memory.
+
+@cindex jump instructions and @code{set}
+@cindex @code{if_then_else} usage
+If @var{lval} is @code{(pc)}, we have a jump instruction, and the
+possibilities for @var{x} are very limited.  It may be a
+@code{label_ref} expression (unconditional jump).  It may be an
+@code{if_then_else} (conditional jump), in which case either the
+second or the third operand must be @code{(pc)} (for the case which
+does not jump) and the other of the two must be a @code{label_ref}
+(for the case which does jump).  @var{x} may also be a @code{mem} or
+@code{(plus:SI (pc) @var{y})}, where @var{y} may be a @code{reg} or a
+@code{mem}; these unusual patterns are used to represent jumps through
+branch tables.
+
+If @var{lval} is neither @code{(cc0)} nor @code{(pc)}, the mode of
+@var{lval} must not be @code{VOIDmode} and the mode of @var{x} must be
+valid for the mode of @var{lval}.
+
+@findex SET_DEST
+@findex SET_SRC
+@var{lval} is customarily accessed with the @code{SET_DEST} macro and
+@var{x} with the @code{SET_SRC} macro.
+
+@findex return
+@item (return)
+As the sole expression in a pattern, represents a return from the
+current function, on machines where this can be done with one
+instruction, such as VAXen.  On machines where a multi-instruction
+``epilogue'' must be executed in order to return from the function,
+returning is done by jumping to a label which precedes the epilogue, and
+the @code{return} expression code is never used.
+
+Inside an @code{if_then_else} expression, represents the value to be
+placed in @code{pc} to return to the caller.
+
+Note that an insn pattern of @code{(return)} is logically equivalent to
+@code{(set (pc) (return))}, but the latter form is never used.
+
+@findex call
+@item (call @var{function} @var{nargs})
+Represents a function call.  @var{function} is a @code{mem} expression
+whose address is the address of the function to be called.
+@var{nargs} is an expression which can be used for two purposes: on
+some machines it represents the number of bytes of stack argument; on
+others, it represents the number of argument registers.
+
+Each machine has a standard machine mode which @var{function} must
+have.  The machine description defines macro @code{FUNCTION_MODE} to
+expand into the requisite mode name.  The purpose of this mode is to
+specify what kind of addressing is allowed, on machines where the
+allowed kinds of addressing depend on the machine mode being
+addressed.
+
+@findex clobber
+@item (clobber @var{x})
+Represents the storing or possible storing of an unpredictable,
+undescribed value into @var{x}, which must be a @code{reg},
+@code{scratch}, @code{parallel} or @code{mem} expression.
+
+One place this is used is in string instructions that store standard
+values into particular hard registers.  It may not be worth the
+trouble to describe the values that are stored, but it is essential to
+inform the compiler that the registers will be altered, lest it
+attempt to keep data in them across the string instruction.
+
+If @var{x} is @code{(mem:BLK (const_int 0))}, it means that all memory
+locations must be presumed clobbered.  If @var{x} is a @code{parallel},
+it has the same meaning as a @code{parallel} in a @code{set} expression.
+
+Note that the machine description classifies certain hard registers as
+``call-clobbered''.  All function call instructions are assumed by
+default to clobber these registers, so there is no need to use
+@code{clobber} expressions to indicate this fact.  Also, each function
+call is assumed to have the potential to alter any memory location,
+unless the function is declared @code{const}.
+
+If the last group of expressions in a @code{parallel} are each a
+@code{clobber} expression whose arguments are @code{reg} or
+@code{match_scratch} (@pxref{RTL Template}) expressions, the combiner
+phase can add the appropriate @code{clobber} expressions to an insn it
+has constructed when doing so will cause a pattern to be matched.
+
+This feature can be used, for example, on a machine that whose multiply
+and add instructions don't use an MQ register but which has an
+add-accumulate instruction that does clobber the MQ register.  Similarly,
+a combined instruction might require a temporary register while the
+constituent instructions might not.
+
+When a @code{clobber} expression for a register appears inside a
+@code{parallel} with other side effects, the register allocator
+guarantees that the register is unoccupied both before and after that
+insn.  However, the reload phase may allocate a register used for one of
+the inputs unless the @samp{&} constraint is specified for the selected
+alternative (@pxref{Modifiers}).  You can clobber either a specific hard
+register, a pseudo register, or a @code{scratch} expression; in the
+latter two cases, GCC will allocate a hard register that is available
+there for use as a temporary.
+
+For instructions that require a temporary register, you should use
+@code{scratch} instead of a pseudo-register because this will allow the
+combiner phase to add the @code{clobber} when required.  You do this by
+coding (@code{clobber} (@code{match_scratch} @dots{})).  If you do
+clobber a pseudo register, use one which appears nowhere else---generate
+a new one each time.  Otherwise, you may confuse CSE@.
+
+There is one other known use for clobbering a pseudo register in a
+@code{parallel}: when one of the input operands of the insn is also
+clobbered by the insn.  In this case, using the same pseudo register in
+the clobber and elsewhere in the insn produces the expected results.
+
+@findex use
+@item (use @var{x})
+Represents the use of the value of @var{x}.  It indicates that the
+value in @var{x} at this point in the program is needed, even though
+it may not be apparent why this is so.  Therefore, the compiler will
+not attempt to delete previous instructions whose only effect is to
+store a value in @var{x}.  @var{x} must be a @code{reg} expression.
+
+In some situations, it may be tempting to add a @code{use} of a
+register in a @code{parallel} to describe a situation where the value
+of a special register will modify the behavior of the instruction.
+An hypothetical example might be a pattern for an addition that can
+either wrap around or use saturating addition depending on the value
+of a special control register:
+
+@example
+(parallel [(set (reg:SI 2) (unspec:SI [(reg:SI 3) 
+                                       (reg:SI 4)] 0))
+           (use (reg:SI 1))])
+@end example
+
+@noindent
+
+This will not work, several of the optimizers only look at expressions
+locally; it is very likely that if you have multiple insns with
+identical inputs to the @code{unspec}, they will be optimized away even
+if register 1 changes in between.
+
+This means that @code{use} can @emph{only} be used to describe
+that the register is live.  You should think twice before adding
+@code{use} statements, more often you will want to use @code{unspec}
+instead.  The @code{use} RTX is most commonly useful to describe that
+a fixed register is implicitly used in an insn.  It is also safe to use
+in patterns where the compiler knows for other reasons that the result
+of the whole pattern is variable, such as @samp{movstr@var{m}} or
+@samp{call} patterns.
+
+During the reload phase, an insn that has a @code{use} as pattern
+can carry a reg_equal note.  These @code{use} insns will be deleted
+before the reload phase exits.
+
+During the delayed branch scheduling phase, @var{x} may be an insn.
+This indicates that @var{x} previously was located at this place in the
+code and its data dependencies need to be taken into account.  These
+@code{use} insns will be deleted before the delayed branch scheduling
+phase exits.
+
+@findex parallel
+@item (parallel [@var{x0} @var{x1} @dots{}])
+Represents several side effects performed in parallel.  The square
+brackets stand for a vector; the operand of @code{parallel} is a
+vector of expressions.  @var{x0}, @var{x1} and so on are individual
+side effect expressions---expressions of code @code{set}, @code{call},
+@code{return}, @code{clobber} or @code{use}.
+
+``In parallel'' means that first all the values used in the individual
+side-effects are computed, and second all the actual side-effects are
+performed.  For example,
+
+@example
+(parallel [(set (reg:SI 1) (mem:SI (reg:SI 1)))
+           (set (mem:SI (reg:SI 1)) (reg:SI 1))])
+@end example
+
+@noindent
+says unambiguously that the values of hard register 1 and the memory
+location addressed by it are interchanged.  In both places where
+@code{(reg:SI 1)} appears as a memory address it refers to the value
+in register 1 @emph{before} the execution of the insn.
+
+It follows that it is @emph{incorrect} to use @code{parallel} and
+expect the result of one @code{set} to be available for the next one.
+For example, people sometimes attempt to represent a jump-if-zero
+instruction this way:
+
+@example
+(parallel [(set (cc0) (reg:SI 34))
+           (set (pc) (if_then_else
+                        (eq (cc0) (const_int 0))
+                        (label_ref @dots{})
+                        (pc)))])
+@end example
+
+@noindent
+But this is incorrect, because it says that the jump condition depends
+on the condition code value @emph{before} this instruction, not on the
+new value that is set by this instruction.
+
+@cindex peephole optimization, RTL representation
+Peephole optimization, which takes place together with final assembly
+code output, can produce insns whose patterns consist of a @code{parallel}
+whose elements are the operands needed to output the resulting
+assembler code---often @code{reg}, @code{mem} or constant expressions.
+This would not be well-formed RTL at any other stage in compilation,
+but it is ok then because no further optimization remains to be done.
+However, the definition of the macro @code{NOTICE_UPDATE_CC}, if
+any, must deal with such insns if you define any peephole optimizations.
+
+@findex cond_exec
+@item (cond_exec [@var{cond} @var{expr}])
+Represents a conditionally executed expression.  The @var{expr} is
+executed only if the @var{cond} is nonzero.  The @var{cond} expression
+must not have side-effects, but the @var{expr} may very well have
+side-effects.
+
+@findex sequence
+@item (sequence [@var{insns} @dots{}])
+Represents a sequence of insns.  Each of the @var{insns} that appears
+in the vector is suitable for appearing in the chain of insns, so it
+must be an @code{insn}, @code{jump_insn}, @code{call_insn},
+@code{code_label}, @code{barrier} or @code{note}.
+
+A @code{sequence} RTX is never placed in an actual insn during RTL
+generation.  It represents the sequence of insns that result from a
+@code{define_expand} @emph{before} those insns are passed to
+@code{emit_insn} to insert them in the chain of insns.  When actually
+inserted, the individual sub-insns are separated out and the
+@code{sequence} is forgotten.
+
+After delay-slot scheduling is completed, an insn and all the insns that
+reside in its delay slots are grouped together into a @code{sequence}.
+The insn requiring the delay slot is the first insn in the vector;
+subsequent insns are to be placed in the delay slot.
+
+@code{INSN_ANNULLED_BRANCH_P} is set on an insn in a delay slot to
+indicate that a branch insn should be used that will conditionally annul
+the effect of the insns in the delay slots.  In such a case,
+@code{INSN_FROM_TARGET_P} indicates that the insn is from the target of
+the branch and should be executed only if the branch is taken; otherwise
+the insn should be executed only if the branch is not taken.
+@xref{Delay Slots}.
+@end table
+
+These expression codes appear in place of a side effect, as the body of
+an insn, though strictly speaking they do not always describe side
+effects as such:
+
+@table @code
+@findex asm_input
+@item (asm_input @var{s})
+Represents literal assembler code as described by the string @var{s}.
+
+@findex unspec
+@findex unspec_volatile
+@item (unspec [@var{operands} @dots{}] @var{index})
+@itemx (unspec_volatile [@var{operands} @dots{}] @var{index})
+Represents a machine-specific operation on @var{operands}.  @var{index}
+selects between multiple machine-specific operations.
+@code{unspec_volatile} is used for volatile operations and operations
+that may trap; @code{unspec} is used for other operations.
+
+These codes may appear inside a @code{pattern} of an
+insn, inside a @code{parallel}, or inside an expression.
+
+@findex addr_vec
+@item (addr_vec:@var{m} [@var{lr0} @var{lr1} @dots{}])
+Represents a table of jump addresses.  The vector elements @var{lr0},
+etc., are @code{label_ref} expressions.  The mode @var{m} specifies
+how much space is given to each address; normally @var{m} would be
+@code{Pmode}.
+
+@findex addr_diff_vec
+@item (addr_diff_vec:@var{m} @var{base} [@var{lr0} @var{lr1} @dots{}] @var{min} @var{max} @var{flags})
+Represents a table of jump addresses expressed as offsets from
+@var{base}.  The vector elements @var{lr0}, etc., are @code{label_ref}
+expressions and so is @var{base}.  The mode @var{m} specifies how much
+space is given to each address-difference.  @var{min} and @var{max}
+are set up by branch shortening and hold a label with a minimum and a
+maximum address, respectively.  @var{flags} indicates the relative
+position of @var{base}, @var{min} and @var{max} to the containing insn
+and of @var{min} and @var{max} to @var{base}.  See rtl.def for details.
+
+@findex prefetch
+@item (prefetch:@var{m} @var{addr} @var{rw} @var{locality})
+Represents prefetch of memory at address @var{addr}.
+Operand @var{rw} is 1 if the prefetch is for data to be written, 0 otherwise;
+targets that do not support write prefetches should treat this as a normal
+prefetch.
+Operand @var{locality} specifies the amount of temporal locality; 0 if there
+is none or 1, 2, or 3 for increasing levels of temporal locality;
+targets that do not support locality hints should ignore this.
+
+This insn is used to minimize cache-miss latency by moving data into a
+cache before it is accessed.  It should use only non-faulting data prefetch
+instructions.
+@end table
+
+@node Incdec
+@section Embedded Side-Effects on Addresses
+@cindex RTL preincrement
+@cindex RTL postincrement
+@cindex RTL predecrement
+@cindex RTL postdecrement
+
+Six special side-effect expression codes appear as memory addresses.
+
+@table @code
+@findex pre_dec
+@item (pre_dec:@var{m} @var{x})
+Represents the side effect of decrementing @var{x} by a standard
+amount and represents also the value that @var{x} has after being
+decremented.  @var{x} must be a @code{reg} or @code{mem}, but most
+machines allow only a @code{reg}.  @var{m} must be the machine mode
+for pointers on the machine in use.  The amount @var{x} is decremented
+by is the length in bytes of the machine mode of the containing memory
+reference of which this expression serves as the address.  Here is an
+example of its use:
+
+@example
+(mem:DF (pre_dec:SI (reg:SI 39)))
+@end example
+
+@noindent
+This says to decrement pseudo register 39 by the length of a @code{DFmode}
+value and use the result to address a @code{DFmode} value.
+
+@findex pre_inc
+@item (pre_inc:@var{m} @var{x})
+Similar, but specifies incrementing @var{x} instead of decrementing it.
+
+@findex post_dec
+@item (post_dec:@var{m} @var{x})
+Represents the same side effect as @code{pre_dec} but a different
+value.  The value represented here is the value @var{x} has @i{before}
+being decremented.
+
+@findex post_inc
+@item (post_inc:@var{m} @var{x})
+Similar, but specifies incrementing @var{x} instead of decrementing it.
+
+@findex post_modify
+@item (post_modify:@var{m} @var{x} @var{y})
+
+Represents the side effect of setting @var{x} to @var{y} and
+represents @var{x} before @var{x} is modified.  @var{x} must be a
+@code{reg} or @code{mem}, but most machines allow only a @code{reg}.
+@var{m} must be the machine mode for pointers on the machine in use.
+The amount @var{x} is decremented by is the length in bytes of the
+machine mode of the containing memory reference of which this expression
+serves as the address.  Note that this is not currently implemented.
+
+The expression @var{y} must be one of three forms:
+@table @code
+@code{(plus:@var{m} @var{x} @var{z})},
+@code{(minus:@var{m} @var{x} @var{z})}, or
+@code{(plus:@var{m} @var{x} @var{i})},
+@end table
+where @var{z} is an index register and @var{i} is a constant.
+
+Here is an example of its use:
+
+@example
+(mem:SF (post_modify:SI (reg:SI 42) (plus (reg:SI 42)
+                                          (reg:SI 48))))
+@end example
+
+This says to modify pseudo register 42 by adding the contents of pseudo
+register 48 to it, after the use of what ever 42 points to.
+
+@findex post_modify
+@item (pre_modify:@var{m} @var{x} @var{expr})
+Similar except side effects happen before the use.
+@end table
+
+These embedded side effect expressions must be used with care.  Instruction
+patterns may not use them.  Until the @samp{flow} pass of the compiler,
+they may occur only to represent pushes onto the stack.  The @samp{flow}
+pass finds cases where registers are incremented or decremented in one
+instruction and used as an address shortly before or after; these cases are
+then transformed to use pre- or post-increment or -decrement.
+
+If a register used as the operand of these expressions is used in
+another address in an insn, the original value of the register is used.
+Uses of the register outside of an address are not permitted within the
+same insn as a use in an embedded side effect expression because such
+insns behave differently on different machines and hence must be treated
+as ambiguous and disallowed.
+
+An instruction that can be represented with an embedded side effect
+could also be represented using @code{parallel} containing an additional
+@code{set} to describe how the address register is altered.  This is not
+done because machines that allow these operations at all typically
+allow them wherever a memory address is called for.  Describing them as
+additional parallel stores would require doubling the number of entries
+in the machine description.
+
+@node Assembler
+@section Assembler Instructions as Expressions
+@cindex assembler instructions in RTL
+
+@cindex @code{asm_operands}, usage
+The RTX code @code{asm_operands} represents a value produced by a
+user-specified assembler instruction.  It is used to represent
+an @code{asm} statement with arguments.  An @code{asm} statement with
+a single output operand, like this:
+
+@smallexample
+asm ("foo %1,%2,%0" : "=a" (outputvar) : "g" (x + y), "di" (*z));
+@end smallexample
+
+@noindent
+is represented using a single @code{asm_operands} RTX which represents
+the value that is stored in @code{outputvar}:
+
+@smallexample
+(set @var{rtx-for-outputvar}
+     (asm_operands "foo %1,%2,%0" "a" 0
+                   [@var{rtx-for-addition-result} @var{rtx-for-*z}]
+                   [(asm_input:@var{m1} "g")
+                    (asm_input:@var{m2} "di")]))
+@end smallexample
+
+@noindent
+Here the operands of the @code{asm_operands} RTX are the assembler
+template string, the output-operand's constraint, the index-number of the
+output operand among the output operands specified, a vector of input
+operand RTX's, and a vector of input-operand modes and constraints.  The
+mode @var{m1} is the mode of the sum @code{x+y}; @var{m2} is that of
+@code{*z}.
+
+When an @code{asm} statement has multiple output values, its insn has
+several such @code{set} RTX's inside of a @code{parallel}.  Each @code{set}
+contains a @code{asm_operands}; all of these share the same assembler
+template and vectors, but each contains the constraint for the respective
+output operand.  They are also distinguished by the output-operand index
+number, which is 0, 1, @dots{} for successive output operands.
+
+@node Insns
+@section Insns
+@cindex insns
+
+The RTL representation of the code for a function is a doubly-linked
+chain of objects called @dfn{insns}.  Insns are expressions with
+special codes that are used for no other purpose.  Some insns are
+actual instructions; others represent dispatch tables for @code{switch}
+statements; others represent labels to jump to or various sorts of
+declarative information.
+
+In addition to its own specific data, each insn must have a unique
+id-number that distinguishes it from all other insns in the current
+function (after delayed branch scheduling, copies of an insn with the
+same id-number may be present in multiple places in a function, but
+these copies will always be identical and will only appear inside a
+@code{sequence}), and chain pointers to the preceding and following
+insns.  These three fields occupy the same position in every insn,
+independent of the expression code of the insn.  They could be accessed
+with @code{XEXP} and @code{XINT}, but instead three special macros are
+always used:
+
+@table @code
+@findex INSN_UID
+@item INSN_UID (@var{i})
+Accesses the unique id of insn @var{i}.
+
+@findex PREV_INSN
+@item PREV_INSN (@var{i})
+Accesses the chain pointer to the insn preceding @var{i}.
+If @var{i} is the first insn, this is a null pointer.
+
+@findex NEXT_INSN
+@item NEXT_INSN (@var{i})
+Accesses the chain pointer to the insn following @var{i}.
+If @var{i} is the last insn, this is a null pointer.
+@end table
+
+@findex get_insns
+@findex get_last_insn
+The first insn in the chain is obtained by calling @code{get_insns}; the
+last insn is the result of calling @code{get_last_insn}.  Within the
+chain delimited by these insns, the @code{NEXT_INSN} and
+@code{PREV_INSN} pointers must always correspond: if @var{insn} is not
+the first insn,
+
+@example
+NEXT_INSN (PREV_INSN (@var{insn})) == @var{insn}
+@end example
+
+@noindent
+is always true and if @var{insn} is not the last insn,
+
+@example
+PREV_INSN (NEXT_INSN (@var{insn})) == @var{insn}
+@end example
+
+@noindent
+is always true.
+
+After delay slot scheduling, some of the insns in the chain might be
+@code{sequence} expressions, which contain a vector of insns.  The value
+of @code{NEXT_INSN} in all but the last of these insns is the next insn
+in the vector; the value of @code{NEXT_INSN} of the last insn in the vector
+is the same as the value of @code{NEXT_INSN} for the @code{sequence} in
+which it is contained.  Similar rules apply for @code{PREV_INSN}.
+
+This means that the above invariants are not necessarily true for insns
+inside @code{sequence} expressions.  Specifically, if @var{insn} is the
+first insn in a @code{sequence}, @code{NEXT_INSN (PREV_INSN (@var{insn}))}
+is the insn containing the @code{sequence} expression, as is the value
+of @code{PREV_INSN (NEXT_INSN (@var{insn}))} if @var{insn} is the last
+insn in the @code{sequence} expression.  You can use these expressions
+to find the containing @code{sequence} expression.
+
+Every insn has one of the following six expression codes:
+
+@table @code
+@findex insn
+@item insn
+The expression code @code{insn} is used for instructions that do not jump
+and do not do function calls.  @code{sequence} expressions are always
+contained in insns with code @code{insn} even if one of those insns
+should jump or do function calls.
+
+Insns with code @code{insn} have four additional fields beyond the three
+mandatory ones listed above.  These four are described in a table below.
+
+@findex jump_insn
+@item jump_insn
+The expression code @code{jump_insn} is used for instructions that may
+jump (or, more generally, may contain @code{label_ref} expressions).  If
+there is an instruction to return from the current function, it is
+recorded as a @code{jump_insn}.
+
+@findex JUMP_LABEL
+@code{jump_insn} insns have the same extra fields as @code{insn} insns,
+accessed in the same way and in addition contain a field
+@code{JUMP_LABEL} which is defined once jump optimization has completed.
+
+For simple conditional and unconditional jumps, this field contains
+the @code{code_label} to which this insn will (possibly conditionally)
+branch.  In a more complex jump, @code{JUMP_LABEL} records one of the
+labels that the insn refers to; the only way to find the others is to
+scan the entire body of the insn.  In an @code{addr_vec},
+@code{JUMP_LABEL} is @code{NULL_RTX}.
+
+Return insns count as jumps, but since they do not refer to any
+labels, their @code{JUMP_LABEL} is @code{NULL_RTX}.
+
+@findex call_insn
+@item call_insn
+The expression code @code{call_insn} is used for instructions that may do
+function calls.  It is important to distinguish these instructions because
+they imply that certain registers and memory locations may be altered
+unpredictably.
+
+@findex CALL_INSN_FUNCTION_USAGE
+@code{call_insn} insns have the same extra fields as @code{insn} insns,
+accessed in the same way and in addition contain a field
+@code{CALL_INSN_FUNCTION_USAGE}, which contains a list (chain of
+@code{expr_list} expressions) containing @code{use} and @code{clobber}
+expressions that denote hard registers and @code{MEM}s used or
+clobbered by the called function.
+
+A @code{MEM} generally points to a stack slots in which arguments passed
+to the libcall by reference (@pxref{Register Arguments,
+FUNCTION_ARG_PASS_BY_REFERENCE}) are stored.  If the argument is
+caller-copied (@pxref{Register Arguments, FUNCTION_ARG_CALLEE_COPIES}),
+the stack slot will be mentioned in @code{CLOBBER} and @code{USE}
+entries; if it's callee-copied, only a @code{USE} will appear, and the
+@code{MEM} may point to addresses that are not stack slots.  These
+@code{MEM}s are used only in libcalls, because, unlike regular function
+calls, @code{CONST_CALL}s (which libcalls generally are, @pxref{Flags,
+CONST_CALL_P}) aren't assumed to read and write all memory, so flow
+would consider the stores dead and remove them.  Note that, since a
+libcall must never return values in memory (@pxref{Aggregate Return,
+RETURN_IN_MEMORY}), there will never be a @code{CLOBBER} for a memory
+address holding a return value.
+
+@code{CLOBBER}ed registers in this list augment registers specified in
+@code{CALL_USED_REGISTERS} (@pxref{Register Basics}).
+
+@findex code_label
+@findex CODE_LABEL_NUMBER
+@item code_label
+A @code{code_label} insn represents a label that a jump insn can jump
+to.  It contains two special fields of data in addition to the three
+standard ones.  @code{CODE_LABEL_NUMBER} is used to hold the @dfn{label
+number}, a number that identifies this label uniquely among all the
+labels in the compilation (not just in the current function).
+Ultimately, the label is represented in the assembler output as an
+assembler label, usually of the form @samp{L@var{n}} where @var{n} is
+the label number.
+
+When a @code{code_label} appears in an RTL expression, it normally
+appears within a @code{label_ref} which represents the address of
+the label, as a number.
+
+Besides as a @code{code_label}, a label can also be represented as a
+@code{note} of type @code{NOTE_INSN_DELETED_LABEL}.
+
+@findex LABEL_NUSES
+The field @code{LABEL_NUSES} is only defined once the jump optimization
+phase is completed and contains the number of times this label is
+referenced in the current function.
+
+@findex LABEL_ALTERNATE_NAME
+The field @code{LABEL_ALTERNATE_NAME} is used to associate a name with
+a @code{code_label}.  If this field is defined, the alternate name will
+be emitted instead of an internally generated label name.
+
+@findex barrier
+@item barrier
+Barriers are placed in the instruction stream when control cannot flow
+past them.  They are placed after unconditional jump instructions to
+indicate that the jumps are unconditional and after calls to
+@code{volatile} functions, which do not return (e.g., @code{exit}).
+They contain no information beyond the three standard fields.
+
+@findex note
+@findex NOTE_LINE_NUMBER
+@findex NOTE_SOURCE_FILE
+@item note
+@code{note} insns are used to represent additional debugging and
+declarative information.  They contain two nonstandard fields, an
+integer which is accessed with the macro @code{NOTE_LINE_NUMBER} and a
+string accessed with @code{NOTE_SOURCE_FILE}.
+
+If @code{NOTE_LINE_NUMBER} is positive, the note represents the
+position of a source line and @code{NOTE_SOURCE_FILE} is the source file name
+that the line came from.  These notes control generation of line
+number data in the assembler output.
+
+Otherwise, @code{NOTE_LINE_NUMBER} is not really a line number but a
+code with one of the following values (and @code{NOTE_SOURCE_FILE}
+must contain a null pointer):
+
+@table @code
+@findex NOTE_INSN_DELETED
+@item NOTE_INSN_DELETED
+Such a note is completely ignorable.  Some passes of the compiler
+delete insns by altering them into notes of this kind.
+
+@findex NOTE_INSN_DELETED_LABEL
+@item NOTE_INSN_DELETED_LABEL
+This marks what used to be a @code{code_label}, but was not used for other
+purposes than taking its address and was transformed to mark that no
+code jumps to it.
+
+@findex NOTE_INSN_BLOCK_BEG
+@findex NOTE_INSN_BLOCK_END
+@item NOTE_INSN_BLOCK_BEG
+@itemx NOTE_INSN_BLOCK_END
+These types of notes indicate the position of the beginning and end
+of a level of scoping of variable names.  They control the output
+of debugging information.
+
+@findex NOTE_INSN_EH_REGION_BEG
+@findex NOTE_INSN_EH_REGION_END
+@item NOTE_INSN_EH_REGION_BEG
+@itemx NOTE_INSN_EH_REGION_END
+These types of notes indicate the position of the beginning and end of a
+level of scoping for exception handling.  @code{NOTE_BLOCK_NUMBER}
+identifies which @code{CODE_LABEL} or @code{note} of type
+@code{NOTE_INSN_DELETED_LABEL} is associated with the given region.
+
+@findex NOTE_INSN_LOOP_BEG
+@findex NOTE_INSN_LOOP_END
+@item NOTE_INSN_LOOP_BEG
+@itemx NOTE_INSN_LOOP_END
+These types of notes indicate the position of the beginning and end
+of a @code{while} or @code{for} loop.  They enable the loop optimizer
+to find loops quickly.
+
+@findex NOTE_INSN_LOOP_CONT
+@item NOTE_INSN_LOOP_CONT
+Appears at the place in a loop that @code{continue} statements jump to.
+
+@findex NOTE_INSN_LOOP_VTOP
+@item NOTE_INSN_LOOP_VTOP
+This note indicates the place in a loop where the exit test begins for
+those loops in which the exit test has been duplicated.  This position
+becomes another virtual start of the loop when considering loop
+invariants.
+
+@findex NOTE_INSN_FUNCTION_END
+@item NOTE_INSN_FUNCTION_END
+Appears near the end of the function body, just before the label that
+@code{return} statements jump to (on machine where a single instruction
+does not suffice for returning).  This note may be deleted by jump
+optimization.
+
+@findex NOTE_INSN_SETJMP
+@item NOTE_INSN_SETJMP
+Appears following each call to @code{setjmp} or a related function.
+@end table
+
+These codes are printed symbolically when they appear in debugging dumps.
+@end table
+
+@cindex @code{TImode}, in @code{insn}
+@cindex @code{HImode}, in @code{insn}
+@cindex @code{QImode}, in @code{insn}
+The machine mode of an insn is normally @code{VOIDmode}, but some
+phases use the mode for various purposes.
+
+The common subexpression elimination pass sets the mode of an insn to
+@code{QImode} when it is the first insn in a block that has already
+been processed.
+
+The second Haifa scheduling pass, for targets that can multiple issue,
+sets the mode of an insn to @code{TImode} when it is believed that the
+instruction begins an issue group.  That is, when the instruction
+cannot issue simultaneously with the previous.  This may be relied on
+by later passes, in particular machine-dependent reorg.
+
+Here is a table of the extra fields of @code{insn}, @code{jump_insn}
+and @code{call_insn} insns:
+
+@table @code
+@findex PATTERN
+@item PATTERN (@var{i})
+An expression for the side effect performed by this insn.  This must be
+one of the following codes: @code{set}, @code{call}, @code{use},
+@code{clobber}, @code{return}, @code{asm_input}, @code{asm_output},
+@code{addr_vec}, @code{addr_diff_vec}, @code{trap_if}, @code{unspec},
+@code{unspec_volatile}, @code{parallel}, @code{cond_exec}, or @code{sequence}.  If it is a @code{parallel},
+each element of the @code{parallel} must be one these codes, except that
+@code{parallel} expressions cannot be nested and @code{addr_vec} and
+@code{addr_diff_vec} are not permitted inside a @code{parallel} expression.
+
+@findex INSN_CODE
+@item INSN_CODE (@var{i})
+An integer that says which pattern in the machine description matches
+this insn, or @minus{}1 if the matching has not yet been attempted.
+
+Such matching is never attempted and this field remains @minus{}1 on an insn
+whose pattern consists of a single @code{use}, @code{clobber},
+@code{asm_input}, @code{addr_vec} or @code{addr_diff_vec} expression.
+
+@findex asm_noperands
+Matching is also never attempted on insns that result from an @code{asm}
+statement.  These contain at least one @code{asm_operands} expression.
+The function @code{asm_noperands} returns a non-negative value for
+such insns.
+
+In the debugging output, this field is printed as a number followed by
+a symbolic representation that locates the pattern in the @file{md}
+file as some small positive or negative offset from a named pattern.
+
+@findex LOG_LINKS
+@item LOG_LINKS (@var{i})
+A list (chain of @code{insn_list} expressions) giving information about
+dependencies between instructions within a basic block.  Neither a jump
+nor a label may come between the related insns.
+
+@findex REG_NOTES
+@item REG_NOTES (@var{i})
+A list (chain of @code{expr_list} and @code{insn_list} expressions)
+giving miscellaneous information about the insn.  It is often
+information pertaining to the registers used in this insn.
+@end table
+
+The @code{LOG_LINKS} field of an insn is a chain of @code{insn_list}
+expressions.  Each of these has two operands: the first is an insn,
+and the second is another @code{insn_list} expression (the next one in
+the chain).  The last @code{insn_list} in the chain has a null pointer
+as second operand.  The significant thing about the chain is which
+insns appear in it (as first operands of @code{insn_list}
+expressions).  Their order is not significant.
+
+This list is originally set up by the flow analysis pass; it is a null
+pointer until then.  Flow only adds links for those data dependencies
+which can be used for instruction combination.  For each insn, the flow
+analysis pass adds a link to insns which store into registers values
+that are used for the first time in this insn.  The instruction
+scheduling pass adds extra links so that every dependence will be
+represented.  Links represent data dependencies, antidependencies and
+output dependencies; the machine mode of the link distinguishes these
+three types: antidependencies have mode @code{REG_DEP_ANTI}, output
+dependencies have mode @code{REG_DEP_OUTPUT}, and data dependencies have
+mode @code{VOIDmode}.
+
+The @code{REG_NOTES} field of an insn is a chain similar to the
+@code{LOG_LINKS} field but it includes @code{expr_list} expressions in
+addition to @code{insn_list} expressions.  There are several kinds of
+register notes, which are distinguished by the machine mode, which in a
+register note is really understood as being an @code{enum reg_note}.
+The first operand @var{op} of the note is data whose meaning depends on
+the kind of note.
+
+@findex REG_NOTE_KIND
+@findex PUT_REG_NOTE_KIND
+The macro @code{REG_NOTE_KIND (@var{x})} returns the kind of
+register note.  Its counterpart, the macro @code{PUT_REG_NOTE_KIND
+(@var{x}, @var{newkind})} sets the register note type of @var{x} to be
+@var{newkind}.
+
+Register notes are of three classes: They may say something about an
+input to an insn, they may say something about an output of an insn, or
+they may create a linkage between two insns.  There are also a set
+of values that are only used in @code{LOG_LINKS}.
+
+These register notes annotate inputs to an insn:
+
+@table @code
+@findex REG_DEAD
+@item REG_DEAD
+The value in @var{op} dies in this insn; that is to say, altering the
+value immediately after this insn would not affect the future behavior
+of the program.
+
+It does not follow that the register @var{op} has no useful value after
+this insn since @var{op} is not necessarily modified by this insn.
+Rather, no subsequent instruction uses the contents of @var{op}.
+
+@findex REG_UNUSED
+@item REG_UNUSED
+The register @var{op} being set by this insn will not be used in a
+subsequent insn.  This differs from a @code{REG_DEAD} note, which
+indicates that the value in an input will not be used subsequently.
+These two notes are independent; both may be present for the same
+register.
+
+@findex REG_INC
+@item REG_INC
+The register @var{op} is incremented (or decremented; at this level
+there is no distinction) by an embedded side effect inside this insn.
+This means it appears in a @code{post_inc}, @code{pre_inc},
+@code{post_dec} or @code{pre_dec} expression.
+
+@findex REG_NONNEG
+@item REG_NONNEG
+The register @var{op} is known to have a nonnegative value when this
+insn is reached.  This is used so that decrement and branch until zero
+instructions, such as the m68k dbra, can be matched.
+
+The @code{REG_NONNEG} note is added to insns only if the machine
+description has a @samp{decrement_and_branch_until_zero} pattern.
+
+@findex REG_NO_CONFLICT
+@item REG_NO_CONFLICT
+This insn does not cause a conflict between @var{op} and the item
+being set by this insn even though it might appear that it does.
+In other words, if the destination register and @var{op} could
+otherwise be assigned the same register, this insn does not
+prevent that assignment.
+
+Insns with this note are usually part of a block that begins with a
+@code{clobber} insn specifying a multi-word pseudo register (which will
+be the output of the block), a group of insns that each set one word of
+the value and have the @code{REG_NO_CONFLICT} note attached, and a final
+insn that copies the output to itself with an attached @code{REG_EQUAL}
+note giving the expression being computed.  This block is encapsulated
+with @code{REG_LIBCALL} and @code{REG_RETVAL} notes on the first and
+last insns, respectively.
+
+@findex REG_LABEL
+@item REG_LABEL
+This insn uses @var{op}, a @code{code_label} or a @code{note} of type
+@code{NOTE_INSN_DELETED_LABEL}, but is not a
+@code{jump_insn}, or it is a @code{jump_insn} that required the label to
+be held in a register.  The presence of this note allows jump
+optimization to be aware that @var{op} is, in fact, being used, and flow
+optimization to build an accurate flow graph.
+@end table
+
+The following notes describe attributes of outputs of an insn:
+
+@table @code
+@findex REG_EQUIV
+@findex REG_EQUAL
+@item REG_EQUIV
+@itemx REG_EQUAL
+This note is only valid on an insn that sets only one register and
+indicates that that register will be equal to @var{op} at run time; the
+scope of this equivalence differs between the two types of notes.  The
+value which the insn explicitly copies into the register may look
+different from @var{op}, but they will be equal at run time.  If the
+output of the single @code{set} is a @code{strict_low_part} expression,
+the note refers to the register that is contained in @code{SUBREG_REG}
+of the @code{subreg} expression.
+
+For @code{REG_EQUIV}, the register is equivalent to @var{op} throughout
+the entire function, and could validly be replaced in all its
+occurrences by @var{op}.  (``Validly'' here refers to the data flow of
+the program; simple replacement may make some insns invalid.)  For
+example, when a constant is loaded into a register that is never
+assigned any other value, this kind of note is used.
+
+When a parameter is copied into a pseudo-register at entry to a function,
+a note of this kind records that the register is equivalent to the stack
+slot where the parameter was passed.  Although in this case the register
+may be set by other insns, it is still valid to replace the register
+by the stack slot throughout the function.
+
+A @code{REG_EQUIV} note is also used on an instruction which copies a
+register parameter into a pseudo-register at entry to a function, if
+there is a stack slot where that parameter could be stored.  Although
+other insns may set the pseudo-register, it is valid for the compiler to
+replace the pseudo-register by stack slot throughout the function,
+provided the compiler ensures that the stack slot is properly
+initialized by making the replacement in the initial copy instruction as
+well.  This is used on machines for which the calling convention
+allocates stack space for register parameters.  See
+@code{REG_PARM_STACK_SPACE} in @ref{Stack Arguments}.
+
+In the case of @code{REG_EQUAL}, the register that is set by this insn
+will be equal to @var{op} at run time at the end of this insn but not
+necessarily elsewhere in the function.  In this case, @var{op}
+is typically an arithmetic expression.  For example, when a sequence of
+insns such as a library call is used to perform an arithmetic operation,
+this kind of note is attached to the insn that produces or copies the
+final value.
+
+These two notes are used in different ways by the compiler passes.
+@code{REG_EQUAL} is used by passes prior to register allocation (such as
+common subexpression elimination and loop optimization) to tell them how
+to think of that value.  @code{REG_EQUIV} notes are used by register
+allocation to indicate that there is an available substitute expression
+(either a constant or a @code{mem} expression for the location of a
+parameter on the stack) that may be used in place of a register if
+insufficient registers are available.
+
+Except for stack homes for parameters, which are indicated by a
+@code{REG_EQUIV} note and are not useful to the early optimization
+passes and pseudo registers that are equivalent to a memory location
+throughout their entire life, which is not detected until later in
+the compilation, all equivalences are initially indicated by an attached
+@code{REG_EQUAL} note.  In the early stages of register allocation, a
+@code{REG_EQUAL} note is changed into a @code{REG_EQUIV} note if
+@var{op} is a constant and the insn represents the only set of its
+destination register.
+
+Thus, compiler passes prior to register allocation need only check for
+@code{REG_EQUAL} notes and passes subsequent to register allocation
+need only check for @code{REG_EQUIV} notes.
+
+@findex REG_WAS_0
+@item REG_WAS_0
+The single output of this insn contained zero before this insn.
+@var{op} is the insn that set it to zero.  You can rely on this note if
+it is present and @var{op} has not been deleted or turned into a @code{note};
+its absence implies nothing.
+@end table
+
+These notes describe linkages between insns.  They occur in pairs: one
+insn has one of a pair of notes that points to a second insn, which has
+the inverse note pointing back to the first insn.
+
+@table @code
+@findex REG_RETVAL
+@item REG_RETVAL
+This insn copies the value of a multi-insn sequence (for example, a
+library call), and @var{op} is the first insn of the sequence (for a
+library call, the first insn that was generated to set up the arguments
+for the library call).
+
+Loop optimization uses this note to treat such a sequence as a single
+operation for code motion purposes and flow analysis uses this note to
+delete such sequences whose results are dead.
+
+A @code{REG_EQUAL} note will also usually be attached to this insn to
+provide the expression being computed by the sequence.
+
+These notes will be deleted after reload, since they are no longer
+accurate or useful.
+
+@findex REG_LIBCALL
+@item REG_LIBCALL
+This is the inverse of @code{REG_RETVAL}: it is placed on the first
+insn of a multi-insn sequence, and it points to the last one.
+
+These notes are deleted after reload, since they are no longer useful or
+accurate.
+
+@findex REG_CC_SETTER
+@findex REG_CC_USER
+@item REG_CC_SETTER
+@itemx REG_CC_USER
+On machines that use @code{cc0}, the insns which set and use @code{cc0}
+set and use @code{cc0} are adjacent.  However, when branch delay slot
+filling is done, this may no longer be true.  In this case a
+@code{REG_CC_USER} note will be placed on the insn setting @code{cc0} to
+point to the insn using @code{cc0} and a @code{REG_CC_SETTER} note will
+be placed on the insn using @code{cc0} to point to the insn setting
+@code{cc0}.
+@end table
+
+These values are only used in the @code{LOG_LINKS} field, and indicate
+the type of dependency that each link represents.  Links which indicate
+a data dependence (a read after write dependence) do not use any code,
+they simply have mode @code{VOIDmode}, and are printed without any
+descriptive text.
+
+@table @code
+@findex REG_DEP_ANTI
+@item REG_DEP_ANTI
+This indicates an anti dependence (a write after read dependence).
+
+@findex REG_DEP_OUTPUT
+@item REG_DEP_OUTPUT
+This indicates an output dependence (a write after write dependence).
+@end table
+
+These notes describe information gathered from gcov profile data.  They
+are stored in the @code{REG_NOTES} field of an insn as an
+@code{expr_list}.
+
+@table @code
+@findex REG_EXEC_COUNT
+@item REG_EXEC_COUNT
+This is used to indicate the number of times a basic block was executed
+according to the profile data.  The note is attached to the first insn in
+the basic block.
+
+@findex REG_BR_PROB
+@item REG_BR_PROB
+This is used to specify the ratio of branches to non-branches of a
+branch insn according to the profile data.  The value is stored as a
+value between 0 and REG_BR_PROB_BASE; larger values indicate a higher
+probability that the branch will be taken.
+
+@findex REG_BR_PRED
+@item REG_BR_PRED
+These notes are found in JUMP insns after delayed branch scheduling
+has taken place.  They indicate both the direction and the likelihood
+of the JUMP@.  The format is a bitmask of ATTR_FLAG_* values.
+
+@findex REG_FRAME_RELATED_EXPR
+@item REG_FRAME_RELATED_EXPR
+This is used on an RTX_FRAME_RELATED_P insn wherein the attached expression
+is used in place of the actual insn pattern.  This is done in cases where
+the pattern is either complex or misleading.
+@end table
+
+For convenience, the machine mode in an @code{insn_list} or
+@code{expr_list} is printed using these symbolic codes in debugging dumps.
+
+@findex insn_list
+@findex expr_list
+The only difference between the expression codes @code{insn_list} and
+@code{expr_list} is that the first operand of an @code{insn_list} is
+assumed to be an insn and is printed in debugging dumps as the insn's
+unique id; the first operand of an @code{expr_list} is printed in the
+ordinary way as an expression.
+
+@node Calls
+@section RTL Representation of Function-Call Insns
+@cindex calling functions in RTL
+@cindex RTL function-call insns
+@cindex function-call insns
+
+Insns that call subroutines have the RTL expression code @code{call_insn}.
+These insns must satisfy special rules, and their bodies must use a special
+RTL expression code, @code{call}.
+
+@cindex @code{call} usage
+A @code{call} expression has two operands, as follows:
+
+@example
+(call (mem:@var{fm} @var{addr}) @var{nbytes})
+@end example
+
+@noindent
+Here @var{nbytes} is an operand that represents the number of bytes of
+argument data being passed to the subroutine, @var{fm} is a machine mode
+(which must equal as the definition of the @code{FUNCTION_MODE} macro in
+the machine description) and @var{addr} represents the address of the
+subroutine.
+
+For a subroutine that returns no value, the @code{call} expression as
+shown above is the entire body of the insn, except that the insn might
+also contain @code{use} or @code{clobber} expressions.
+
+@cindex @code{BLKmode}, and function return values
+For a subroutine that returns a value whose mode is not @code{BLKmode},
+the value is returned in a hard register.  If this register's number is
+@var{r}, then the body of the call insn looks like this:
+
+@example
+(set (reg:@var{m} @var{r})
+     (call (mem:@var{fm} @var{addr}) @var{nbytes}))
+@end example
+
+@noindent
+This RTL expression makes it clear (to the optimizer passes) that the
+appropriate register receives a useful value in this insn.
+
+When a subroutine returns a @code{BLKmode} value, it is handled by
+passing to the subroutine the address of a place to store the value.
+So the call insn itself does not ``return'' any value, and it has the
+same RTL form as a call that returns nothing.
+
+On some machines, the call instruction itself clobbers some register,
+for example to contain the return address.  @code{call_insn} insns
+on these machines should have a body which is a @code{parallel}
+that contains both the @code{call} expression and @code{clobber}
+expressions that indicate which registers are destroyed.  Similarly,
+if the call instruction requires some register other than the stack
+pointer that is not explicitly mentioned it its RTL, a @code{use}
+subexpression should mention that register.
+
+Functions that are called are assumed to modify all registers listed in
+the configuration macro @code{CALL_USED_REGISTERS} (@pxref{Register
+Basics}) and, with the exception of @code{const} functions and library
+calls, to modify all of memory.
+
+Insns containing just @code{use} expressions directly precede the
+@code{call_insn} insn to indicate which registers contain inputs to the
+function.  Similarly, if registers other than those in
+@code{CALL_USED_REGISTERS} are clobbered by the called function, insns
+containing a single @code{clobber} follow immediately after the call to
+indicate which registers.
+
+@node Sharing
+@section Structure Sharing Assumptions
+@cindex sharing of RTL components
+@cindex RTL structure sharing assumptions
+
+The compiler assumes that certain kinds of RTL expressions are unique;
+there do not exist two distinct objects representing the same value.
+In other cases, it makes an opposite assumption: that no RTL expression
+object of a certain kind appears in more than one place in the
+containing structure.
+
+These assumptions refer to a single function; except for the RTL
+objects that describe global variables and external functions,
+and a few standard objects such as small integer constants,
+no RTL objects are common to two functions.
+
+@itemize @bullet
+@cindex @code{reg}, RTL sharing
+@item
+Each pseudo-register has only a single @code{reg} object to represent it,
+and therefore only a single machine mode.
+
+@cindex symbolic label
+@cindex @code{symbol_ref}, RTL sharing
+@item
+For any symbolic label, there is only one @code{symbol_ref} object
+referring to it.
+
+@cindex @code{const_int}, RTL sharing
+@item
+All @code{const_int} expressions with equal values are shared.
+
+@cindex @code{pc}, RTL sharing
+@item
+There is only one @code{pc} expression.
+
+@cindex @code{cc0}, RTL sharing
+@item
+There is only one @code{cc0} expression.
+
+@cindex @code{const_double}, RTL sharing
+@item
+There is only one @code{const_double} expression with value 0 for
+each floating point mode.  Likewise for values 1 and 2.
+
+@cindex @code{label_ref}, RTL sharing
+@cindex @code{scratch}, RTL sharing
+@item
+No @code{label_ref} or @code{scratch} appears in more than one place in
+the RTL structure; in other words, it is safe to do a tree-walk of all
+the insns in the function and assume that each time a @code{label_ref}
+or @code{scratch} is seen it is distinct from all others that are seen.
+
+@cindex @code{mem}, RTL sharing
+@item
+Only one @code{mem} object is normally created for each static
+variable or stack slot, so these objects are frequently shared in all
+the places they appear.  However, separate but equal objects for these
+variables are occasionally made.
+
+@cindex @code{asm_operands}, RTL sharing
+@item
+When a single @code{asm} statement has multiple output operands, a
+distinct @code{asm_operands} expression is made for each output operand.
+However, these all share the vector which contains the sequence of input
+operands.  This sharing is used later on to test whether two
+@code{asm_operands} expressions come from the same statement, so all
+optimizations must carefully preserve the sharing if they copy the
+vector at all.
+
+@item
+No RTL object appears in more than one place in the RTL structure
+except as described above.  Many passes of the compiler rely on this
+by assuming that they can modify RTL objects in place without unwanted
+side-effects on other insns.
+
+@findex unshare_all_rtl
+@item
+During initial RTL generation, shared structure is freely introduced.
+After all the RTL for a function has been generated, all shared
+structure is copied by @code{unshare_all_rtl} in @file{emit-rtl.c},
+after which the above rules are guaranteed to be followed.
+
+@findex copy_rtx_if_shared
+@item
+During the combiner pass, shared structure within an insn can exist
+temporarily.  However, the shared structure is copied before the
+combiner is finished with the insn.  This is done by calling
+@code{copy_rtx_if_shared}, which is a subroutine of
+@code{unshare_all_rtl}.
+@end itemize
+
+@node Reading RTL
+@section Reading RTL
+
+To read an RTL object from a file, call @code{read_rtx}.  It takes one
+argument, a stdio stream, and returns a single RTL object.  This routine
+is defined in @file{read-rtl.c}.  It is not available in the compiler
+itself, only the various programs that generate the compiler back end
+from the machine description.
+
+People frequently have the idea of using RTL stored as text in a file as
+an interface between a language front end and the bulk of GCC@.  This
+idea is not feasible.
+
+GCC was designed to use RTL internally only.  Correct RTL for a given
+program is very dependent on the particular target machine.  And the RTL
+does not contain all the information about the program.
+
+The proper way to interface GCC to a new language front end is with
+the ``tree'' data structure, described in the files @file{tree.h} and
+@file{tree.def}.  The documentation for this structure (@pxref{Trees})
+is incomplete.
diff --git a/contrib/gcc/doc/service.texi b/contrib/gcc/doc/service.texi
new file mode 100644
index 0000000..8637744
--- /dev/null
+++ b/contrib/gcc/doc/service.texi
@@ -0,0 +1,30 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+@c 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Service
+@chapter How To Get Help with GCC
+
+If you need help installing, using or changing GCC, there are two
+ways to find it:
+
+@itemize @bullet
+@item
+Send a message to a suitable network mailing list.  First try
+@email{gcc-help@@gcc.gnu.org} (for help installing or using GCC), and if
+that brings no response, try @email{gcc@@gcc.gnu.org}.  For help
+changing GCC, ask @email{gcc@@gcc.gnu.org}.  If you think you have found
+a bug in GCC, please report it following the instructions at
+@pxref{Bug Reporting}.
+
+@item
+Look in the service directory for someone who might help you for a fee.
+The service directory is found at
+@uref{http://www.gnu.org/prep/service.html}.
+@end itemize
+
+@c For further information, see
+@c @uref{http://gcc.gnu.org/cgi-bin/fom.cgi?file=12}.
+@c FIXME: this URL may be too volatile, this FAQ entry needs to move to
+@c the regular web pages before we can uncomment the reference.
diff --git a/contrib/gcc/doc/sourcebuild.texi b/contrib/gcc/doc/sourcebuild.texi
new file mode 100644
index 0000000..670d501
--- /dev/null
+++ b/contrib/gcc/doc/sourcebuild.texi
@@ -0,0 +1,875 @@
+@c Copyright (C) 2002 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Source Tree
+@chapter Source Tree Structure and Build System
+
+This chapter describes the structure of the GCC source tree, and how
+GCC is built.  The user documentation for building and installing GCC
+is in a separate manual (@uref{http://gcc.gnu.org/install/}), with
+which it is presumed that you are familiar.
+
+@menu
+* Configure Terms:: Configuration terminology and history.
+* Top Level::       The top level source directory.
+* gcc Directory::   The @file{gcc} subdirectory.
+* Test Suites::     The GCC test suites.
+@end menu
+
+@include configterms.texi
+
+@node Top Level
+@section Top Level Source Directory
+
+The top level source directory in a GCC distribution contains several
+files and directories that are shared with other software
+distributions such as that of GNU Binutils.  It also contains several
+subdirectories that contain parts of GCC and its runtime libraries:
+
+@table @file
+@item boehm-gc
+The Boehm conservative garbage collector, used as part of the Java
+runtime library.
+
+@item contrib
+Contributed scripts that may be found useful in conjunction with GCC@.
+One of these, @file{contrib/texi2pod.pl}, is used to generate man
+pages from Texinfo manuals as part of the GCC build process.
+
+@item fastjar
+An implementation of the @command{jar} command, used with the Java
+front end.
+
+@item gcc
+The main sources of GCC itself (except for runtime libraries),
+including optimizers, support for different target architectures,
+language front ends, and test suites.  @xref{gcc Directory, , The
+@file{gcc} Subdirectory}, for details.
+
+@item include
+Headers for the @code{libiberty} library.
+
+@item libchill
+The CHILL runtime library.
+
+@item libf2c
+The Fortran runtime library.
+
+@item libffi
+The @code{libffi} library, used as part of the Java runtime library.
+
+@item libiberty
+The @code{libibery} library, used for portability and for some
+generally useful data structures and algorithms.  @xref{Top, ,
+Introduction, libiberty, @sc{gnu} libiberty}, for more information
+about this library.
+
+@item libjava
+The Java runtime library.
+
+@item libobjc
+The Objective-C runtime library.
+
+@item libstdc++-v3
+The C++ runtime library.
+
+@item maintainer-scripts
+Scripts used by the @code{gccadmin} account on @code{gcc.gnu.org}.
+
+@item zlib
+The @code{zlib} compression library, used by the Java front end and as
+part of the Java runtime library.
+@end table
+
+The build system in the top level directory, including how recursion
+into subdirectories works and how building runtime libraries for
+multilibs is handled, is documented in a separate manual, included
+with GNU Binutils.  @xref{Top, , GNU configure and build system,
+configure, The GNU configure and build system}, for details.
+
+@node gcc Directory
+@section The @file{gcc} Subdirectory
+
+The @file{gcc} directory contains many files that are part of the C
+sources of GCC, other files used as part of the configuration and
+build process, and subdirectories including documentation and a
+test suite.  The files that are sources of GCC are documented in a
+separate chapter.  @xref{Passes, , Passes and Files of the Compiler}.
+
+@menu
+* Subdirectories:: Subdirectories of @file{gcc}.
+* Configuration::  The configuration process, and the files it uses.
+* Build::          The build system in the @file{gcc} directory.
+* Makefile::       Targets in @file{gcc/Makefile}.
+* Library Files::  Library source files and headers under @file{gcc/}.
+* Headers::        Headers installed by GCC.
+* Documentation::  Building documentation in GCC.
+* Front End::      Anatomy of a language front end.
+* Back End::       Anatomy of a target back end.
+@end menu
+
+@node Subdirectories
+@subsection Subdirectories of @file{gcc}
+
+The @file{gcc} directory contains the following subdirectories:
+
+@table @file
+@item @var{language}
+Subdirectories for various languages.  Directories containing a file
+@file{config-lang.in} are language subdirectories.  The contents of
+the subdirectories @file{cp} (for C++) and @file{objc} (for
+Objective-C) are documented in this manual (@pxref{Passes, , Passes
+and Files of the Compiler}); those for other languages are not.
+@xref{Front End, , Anatomy of a Language Front End}, for details of
+the files in these directories.
+
+@item config
+Configuration files for supported architectures and operating
+systems.  @xref{Back End, , Anatomy of a Target Back End}, for
+details of the files in thie directory.
+
+@item doc
+Texinfo documentation for GCC, together with automatically generated
+man pages and support for converting the installation manual to
+HTML@.  @xref{Documentation}.
+
+@item fixinc
+The support for fixing system headers to work with GCC@.  See
+@file{fixinc/README} for more information.  The headers fixed by this
+mechanism are installed in @file{@var{libsubdir}/include}.  Along with
+those headers, @file{README-fixinc} is also installed, as
+@file{@var{libsubdir}/include/README}.
+
+@item ginclude
+System headers installed by GCC, mainly those required by the C
+standard of freestanding implementations.  @xref{Headers, , Headers
+Installed by GCC}, for details of when these and other headers are
+installed.
+
+@item intl
+GNU @code{libintl}, from GNU @code{gettext}, for systems which do not
+include it in libc.  Properly, this directory should be at top level,
+parallel to the @file{gcc} directory.
+
+@item po
+Message catalogs with translations of messages produced by GCC into
+various languages, @file{@var{language}.po}.  This directory also
+contains @file{gcc.pot}, the template for these message catalogues,
+@file{exgettext}, a wrapper around @command{gettext} to extract the
+messages from the GCC sources and create @file{gcc.pot}, which is run
+by @command{make gcc.pot}, and @file{EXCLUDES}, a list of files from
+which messages should not be extracted.
+
+@item testsuite
+The GCC test suites (except for those for runtime libraries).
+@xref{Test Suites}.
+@end table
+
+@node Configuration
+@subsection Configuration in the @file{gcc} Directory
+
+The @file{gcc} directory is configured with an Autoconf-generated
+script @file{configure}.  The @file{configure} script is generated
+from @file{configure.in} and @file{aclocal.m4}.  From the files
+@file{configure.in} and @file{acconfig.h}, Autoheader generates the
+file @file{config.in}.  The file @file{cstamp-h.in} is used as a
+timestamp.
+
+@menu
+* Config Fragments::     Scripts used by @file{configure}.
+* System Config::        The @file{config.gcc} file.
+* Configuration Files::  Files created by running @file{configure}.
+@end menu
+
+@node Config Fragments
+@subsubsection Scripts Used by @file{configure}
+
+@file{configure} uses some other scripts to help in its work:
+
+@itemize @bullet
+@item The standard GNU @file{config.sub} and @file{config.guess}
+files, kept in the top level directory, are used.  FIXME: when is the
+@file{config.guess} file in the @file{gcc} directory (that just calls
+the top level one) used?
+
+@item The file @file{config.gcc} is used to handle configuration
+specific to the particular build, host or target machine.  (In
+general, this should only be used for features that cannot reasonably
+be tested in Autoconf feature tests.)  @xref{System Config, , The
+@file{config.gcc} File}, for details of the contents of this file.
+
+@item Each language subdirectory has a file
+@file{@var{language}/config-lang.in} that is used for
+front-end-specific configuration.  @xref{Front End Config, , The Front
+End @file{config-lang.in} File}, for details of this file.
+
+@item A helper script @file{configure.frag} is used as part of
+creating the output of @file{configure}.
+@end itemize
+
+@node System Config
+@subsubsection The @file{config.gcc} File
+
+FIXME: document the contents of this file, and what variables should
+be set to control build, host and target configuration.
+
+@include configfiles.texi
+
+@node Build
+@subsection Build System in the @file{gcc} Directory
+
+FIXME: describe the build system, including what is built in what
+stages.  Also list the various source files that are used in the build
+process but aren't source files of GCC itself and so aren't documented
+below (@pxref{Passes}).
+
+@include makefile.texi
+
+@node Library Files
+@subsection Library Source Files and Headers under the @file{gcc} Directory
+
+FIXME: list here, with explanation, all the C source files and headers
+under the @file{gcc} directory that aren't built into the GCC
+executable but rather are part of runtime libraries and object files,
+such as @file{crtstuff.c} and @file{unwind-dw2.c}.  @xref{Headers, ,
+Headers Installed by GCC}, for more information about the
+@file{ginclude} directory.
+
+@node Headers
+@subsection Headers Installed by GCC
+
+In general, GCC expects the system C library to provide most of the
+headers to be used with it.  However, GCC will fix those headers if
+necessary to make them work with GCC, and will install some headers
+required of freestanding implementations.  These headers are installed
+in @file{@var{libsubdir}/include}.  Headers for non-C runtime
+libraries are also installed by GCC; these are not documented here.
+(FIXME: document them somewhere.)
+
+Several of the headers GCC installs are in the @file{ginclude}
+directory.  These headers, @file{iso646.h},
+@file{stdarg.h}, @file{stdbool.h}, @file{stddef.h} and
+@file{varargs.h}, are installed in @file{@var{libsubdir}/include},
+unless the target Makefile fragment (@pxref{Target Fragment})
+overrides this by setting @code{USER_H}.
+
+In addition to these headers and those generated by fixing system
+headers to work with GCC, some other headers may also be installed in
+@file{@var{libsubdir}/include}.  @file{config.gcc} may set
+@code{extra_headers}; this specifies additional headers under
+@file{config} to be installed on some systems.  GCC normally installs
+a @code{<float.h>} file; these are kept as
+@file{config/float-@var{format}.h}, where @var{format} is specified by
+a @code{float_format} setting in @file{config.gcc}, and a setting
+@samp{float_format=none} disables installation of this header.  GCC
+also installs its own version of @code{<limits.h>}; this is generated
+from @file{glimits.h}, together with @file{limitx.h} and
+@file{limity.h} if the system also has its own version of
+@code{<limits.h>}.  (GCC provides its own header because it is
+required of ISO C freestanding implementations, but needs to include
+the system header from its own header as well because other standards
+such as POSIX specify additional values to be defined in
+@code{<limits.h>}.)  The system's @code{<limits.h>} header is used via
+@file{@var{libsubdir}/include/syslimits.h}, which is copied from
+@file{gsyslimits.h} if it does not need fixing to work with GCC; if it
+needs fixing, @file{syslimits.h} is the fixed copy.
+
+@node Documentation
+@subsection Building Documentation
+
+The main GCC documentation is in the form of manuals in Texinfo
+format.  These are installed in Info format, and DVI versions may be
+generated by @command{make dvi}.  In addition, some man pages are
+generated from the Texinfo manuals, there are some other text files
+with miscellaneous documentation, and runtime libraries have their own
+documentation outside the @file{gcc} directory.  FIXME: document the
+documentation for runtime libraries somewhere.
+
+@menu
+* Texinfo Manuals::      GCC manuals in Texinfo format.
+* Man Page Generation::  Generating man pages from Texinfo manuals.
+* Miscellaneous Docs::   Miscellaneous text files with documentation.
+@end menu
+
+@node Texinfo Manuals
+@subsubsection Texinfo Manuals
+
+The manuals for GCC as a whole, and the C and C++ front ends, are in
+files @file{doc/*.texi}.  Other front ends have their own manuals in
+files @file{@var{language}/*.texi}.  Common files
+@file{doc/include/*.texi} are provided which may be included in
+multiple manuals; the following files are in @file{doc/include}:
+
+@table @file
+@item fdl.texi
+The GNU Free Documentation License.
+@item funding.texi
+The section ``Funding Free Software''.
+@item gcc-common.texi
+Common definitions for manuals.
+@item gpl.texi
+The GNU General Public License.
+@item texinfo.tex
+A copy of @file{texinfo.tex} known to work with the GCC manuals.
+@end table
+
+DVI formatted manuals are generated by @command{make dvi}, which uses
+@command{texi2dvi} (via the Makefile macro @code{$(TEXI2DVI)}).  Info
+manuals are generated by @command{make info} (which is run as part of
+a bootstrap); this generates the manuals in the source directory,
+using @command{makeinfo} via the Makefile macro @code{$(MAKEINFO)},
+and they are included in release distributions.
+
+Manuals are also provided on the GCC web site, in both HTML and
+PostScript forms.  This is done via the script
+@file{maintainer-scripts/update_web_docs}.  Each manual to be
+provided online must be listed in the definition of @code{MANUALS} in
+that file; a file @file{@var{name}.texi} must only appear once in the
+source tree, and the output manual must have the same name as the
+source file.  (However, other Texinfo files, included in manuals but
+not themselves the root files of manuals, may have names that appear
+more than once in the source tree.)  The manual file
+@file{@var{name}.texi} should only include other files in its own
+directory or in @file{doc/include}.  HTML manuals will be generated by
+@command{makeinfo --html} and PostScript manuals by @command{texi2dvi}
+and @command{dvips}.  All Texinfo files that are parts of manuals must
+be checked into CVS, even if they are generated files, for the
+generation of online manuals to work.
+
+The installation manual, @file{doc/install.texi}, is also provided on
+the GCC web site.  The HTML version is generated by the script
+@file{doc/install.texi2html}.
+
+@node Man Page Generation
+@subsubsection Man Page Generation
+
+Because of user demand, in addition to full Texinfo manuals, man pages
+are provided which contain extracts from those manuals.  These man
+pages are generated from the Texinfo manuals using
+@file{contrib/texi2pod.pl} and @command{pod2man}.  (The man page for
+@command{g++}, @file{cp/g++.1}, just contains a @samp{.so} reference
+to @file{gcc.1}, but all the other man pages are generated from
+Texinfo manuals.)
+
+Because many systems may not have the necessary tools installed to
+generate the man pages, they are only generated if the
+@file{configure} script detects that recent enough tools are
+installed, and the Makefiles allow generating man pages to fail
+without aborting the build.  Man pages are also included in release
+distributions.  They are generated in the source directory.
+
+Magic comments in Texinfo files starting @samp{@@c man} control what
+parts of a Texinfo file go into a man page.  Only a subset of Texinfo
+is supported by @file{texi2pod.pl}, and it may be necessary to add
+support for more Texinfo features to this script when generating new
+man pages.  To improve the man page output, some special Texinfo
+macros are provided in @file{doc/include/gcc-common.texi} which
+@file{texi2pod.pl} understands:
+
+@table @code
+@item @@gcctabopt
+Use in the form @samp{@@table @@gcctabopt} for tables of options,
+where for printed output the effect of @samp{@@code} is better than
+that of @samp{@@option} but for man page output a different effect is
+wanted.
+@item @@gccoptlist
+Use for summary lists of options in manuals.
+@item @@gol
+Use at the end of each line inside @samp{@@gccoptlist}.  This is
+necessary to avoid problems with differences in how the
+@samp{@@gccoptlist} macro is handled by different Texinfo formatters.
+@end table
+
+FIXME: describe the @file{texi2pod.pl} input language and magic
+comments in more detail.
+
+@node Miscellaneous Docs
+@subsubsection Miscellaneous Documentation
+
+In addition to the formal documentation that is installed by GCC,
+there are several other text files with miscellaneous documentation:
+
+@table @file
+@item ABOUT-GCC-NLS
+Notes on GCC's Native Language Support.  FIXME: this should be part of
+this manual rather than a separate file.
+@item ABOUT-NLS
+Notes on the Free Translation Project.
+@item COPYING
+The GNU General Public License.
+@item COPYING.LIB
+The GNU Lesser General Public License.
+@item *ChangeLog*
+@itemx */ChangeLog*
+Change log files for various parts of GCC@.
+@item LANGUAGES
+Details of a few changes to the GCC front-end interface.  FIXME: the
+information in this file should be part of general documentation of
+the front-end interface in this manual.
+@item ONEWS
+Information about new features in old versions of GCC@.  (For recent
+versions, the information is on the GCC web site.)
+@item README.Portability
+Information about portability issues when writing code in GCC@.  FIXME:
+why isn't this part of this manual or of the GCC Coding Conventions?
+@item SERVICE
+A pointer to the GNU Service Directory.
+@end table
+
+FIXME: document such files in subdirectories, at least @file{config},
+@file{cp}, @file{objc}, @file{testsuite}.
+
+@node Front End
+@subsection Anatomy of a Language Front End
+
+A front end for a language in GCC has the following parts:
+
+@itemize @bullet
+@item
+A directory @file{@var{language}} under @file{gcc} containing source
+files for that front end.  @xref{Front End Directory, , The Front End
+@file{@var{language}} Directory}, for details.
+@item
+A mention of the language in the list of supported languages in
+@file{gcc/doc/install.texi}.
+@item
+Details of contributors to that front end in
+@file{gcc/doc/contrib.texi}.  If the details are in that front end's
+own manual then there should be a link to that manual's list in
+@file{contrib.texi}.
+@item
+Information about support for that language in
+@file{gcc/doc/frontends.texi}.
+@item
+Information about standards for that language, and the front end's
+support for them, in @file{gcc/doc/standards.texi}.  This may be a
+link to such information in the front end's own manual.
+@item
+Details of source file suffixes for that language and @option{-x
+@var{lang}} options supported, in @file{gcc/doc/invoke.texi}.
+@item
+Entries in @code{default_compilers} in @file{gcc.c} for source file
+suffixes for that language.
+@item
+Preferably test suites, which may be under @file{gcc/testsuite} or
+runtime library directories.  FIXME: document somewhere how to write
+test suite harnesses.
+@item
+Probably a runtime library for the language, outside the @file{gcc}
+directory.  FIXME: document this further.
+@item
+Details of the directories of any runtime libraries in
+@file{gcc/doc/sourcebuild.texi}.
+@end itemize
+
+If the front end is added to the official GCC CVS repository, the
+following are also necessary:
+
+@itemize @bullet
+@item
+At least one GNATS category for bugs in that front end and runtime
+libraries.  This category needs to be mentioned in
+@file{gcc/gccbug.in}, and in @file{gnats.html} on the GCC web site, as
+well as being added to the GNATS database.
+@item
+Normally, one or more maintainers of that front end listed in
+@file{MAINTAINERS}.
+@item
+Mentions on the GCC web site in @file{index.html} and
+@file{frontends.html}, with any relevant links on
+@file{readings.html}.  (Front ends that are not an official part of
+GCC may also be listed on @file{frontends.html}, with relevant links.)
+@item
+A news item on @file{index.html}, and possibly an announcement on the
+@email{gcc-announce@@gcc.gnu.org} mailing list.
+@item
+The front end's manuals should be mentioned in
+@file{maintainer-scripts/update_web_docs} (@pxref{Texinfo Manuals})
+and the online manuals should be linked to from
+@file{onlinedocs/index.html}.
+@item
+Any old releases or CVS repositories of the front end, before its
+inclusion in GCC, should be made available on the GCC FTP site
+@uref{ftp://gcc.gnu.org/pub/gcc/old-releases/}.
+@item
+The release and snapshot script @file{maintainer-scripts/gcc_release}
+should be updated to generate appropriate tarballs for this front end.
+@item
+If this front end includes its own version files that include the
+current date, @file{maintainer-scripts/update_version} should be
+updated accordingly.
+@item
+@file{CVSROOT/modules} in the GCC CVS repository should be updated.
+@end itemize
+
+@menu
+* Front End Directory::  The front end @file{@var{language}} directory.
+* Front End Config::     The front end @file{config-lang.in} file.
+@end menu
+
+@node Front End Directory
+@subsubsection The Front End @file{@var{language}} Directory
+
+A front end @file{@var{language}} directory contains the source files
+of that front end (but not of any runtime libraries, which should be
+outside the @file{gcc} directory).  This includes documentation, and
+possibly some subsidiary programs build alongside the front end.
+Certain files are special and other parts of the compiler depend on
+their names:
+
+@table @file
+@item config-lang.in
+This file is required in all language subdirectories.  @xref{Front End
+Config, , The Front End @file{config-lang.in} File}, for details of
+its contents
+@item Make-lang.in
+This file is required in all language subdirectories.  It contains
+targets @code{@var{lang}.@var{hook}} (where @code{@var{lang}} is the
+setting of @code{language} in @file{config-lang.in}) for the following
+values of @code{@var{hook}}, and any other Makefile rules required to
+build those targets (which may if necessary use other Makefiles
+specified in @code{outputs} in @file{config-lang.in}, although this is
+deprecated).
+
+@table @code
+@item all.build
+@itemx all.cross
+@itemx start.encap
+@itemx rest.encap
+FIXME: exactly what goes in each of these targets?
+@item info
+Build info documentation for the front end, in the source directory.
+This target is only called by @command{make bootstrap} if a suitable
+version of @command{makeinfo} is available, so does not need to check
+for this, and should fail if an error occurs.
+@item dvi
+Build DVI documentation for the front end, in the build directory.
+This should be done using @code{$(TEXI2DVI)}, with appropriate
+@option{-I} arguments pointing to directories of included files.
+@item generated-manpages
+Build generated man pages for the front end from Texinfo manuals
+(@pxref{Man Page Generation}), in the source directory.  This target
+is only called if the necessary tools are available, but should ignore
+errors so as not to stop the build if errors occur; man pages are
+optional and the tools involved may be installed in a broken way.
+@item install-normal
+FIXME: what is this target for?
+@item install-common
+Install everything that is part of the front end, apart from the
+compiler executables listed in @code{compilers} in
+@file{config-lang.in} that are installed in @file{@var{libsubdir}} by
+the main @file{Makefile}.
+@item install-info
+Install info documentation for the front end, if it is present in the
+source directory.  (It may not be present if a suitable version of
+@command{makeinfo} was not installed.)  This target should run the
+command @command{install-info} to update the info directory, but
+should ignore errors when running that command.
+@item install-man
+Install man pages for the front end.  This target should ignore
+errors.
+@item uninstall
+Uninstall files installed by installing the compiler.  This is
+currently documented not to be supported, so the hook need not do
+anything.
+@item mostlyclean
+@itemx clean
+@itemx distclean
+@itemx extraclean
+@itemx maintainer-clean
+Except for @code{extraclean}, the language parts of the standard GNU
+@samp{*clean} targets. @xref{Standard Targets, , Standard Targets for
+Users, standards, GNU Coding Standards}, for details of the standard
+targets.  @code{extraclean} does @code{distclean} and also deletes
+anything likely to be found in the source directory that shouldn't be
+in the distribution.  For GCC, @code{maintainer-clean} should delete
+all generated files in the source directory that are not checked into
+CVS, but should not delete anything checked into CVS@.
+@item stage1
+@itemx stage2
+@itemx stage3
+@itemx stage4
+Move to the stage directory files not included in @code{stagestuff} in
+@file{config-lang.in} or otherwise moved by the main @file{Makefile}.
+@end table
+
+@item lang-options.h
+This file provides entries for @code{documented_lang_options} in
+@file{toplev.c} describing command-line options the front end accepts
+for @option{--help} output.
+@item lang-specs.h
+This file provides entries for @code{default_compilers} in
+@file{gcc.c} which override the default of giving an error that a
+compiler for that language is not installed.
+@item @var{language}-tree.def
+This file, which need not exist, defines any language-specific tree
+codes.
+@end table
+
+@node Front End Config
+@subsubsection The Front End @file{config-lang.in} File
+
+Each language subdirectory contains a @file{config-lang.in} file.
+This file is a shell script that may define some variables describing
+the language:
+
+@table @code
+@item language
+This definition must be present, and gives the name of the language
+for some purposes such as arguments to @option{--enable-languages}.
+@item lang_requires
+If defined, this variable lists (space-separated) language front ends
+other than C that this front end requires to be enabled (with the
+names given being their @code{language} settings).  For example, the
+Java front end depends on the C++ front end, so sets
+@samp{lang_requires=c++}.
+@item target_libs
+If defined, this variable lists (space-separated) targets in the top
+level @file{Makefile} to build the runtime libraries for this
+language, such as @code{target-libobjc}.
+@item lang_dirs
+If defined, this variable lists (space-separated) top level
+directories (parallel to @file{gcc}), apart from the runtime libraries,
+that should not be configured if this front end is not built.
+@item build_by_default
+If defined to @samp{no}, this language front end is not built unless
+enabled in a @option{--enable-languages} argument.  Otherwise, front
+ends are built by default, subject to any special logic in
+@file{configure.in} (as is present to disable the Ada front end if the
+Ada compiler is not already installed).
+@item boot_language
+If defined to @samp{yes}, this front end is built in stage 1 of the
+bootstrap.  This is only relevant to front ends written in their own
+languages.
+@item compilers
+If defined, a space-separated list of compiler executables that should
+be installed in @file{@var{libsubdir}}.  The names here will each end
+with @samp{\$(exeext)}.
+@item stagestuff
+If defined, a space-separated list of files that should be moved to
+the @file{stage@var{n}} directories in each stage of bootstrap.
+@item outputs
+If defined, a space-separated list of files that should be generated
+by @file{configure} substituting values in them.  This mechanism can
+be used to create a file @file{@var{language}/Makefile} from
+@file{@var{language}/Makefile.in}, but this is deprecated, building
+everything from the single @file{gcc/Makefile} is preferred.
+@end table
+
+@node Back End
+@subsection Anatomy of a Target Back End
+
+A back end for a target architecture in GCC has the following parts:
+
+@itemize @bullet
+@item
+A directory @file{@var{machine}} under @file{gcc/config}, containing a
+machine description @file{@var{machine}.md} file (@pxref{Machine Desc,
+, Machine Descriptions}), header files @file{@var{machine}.h} and
+@file{@var{machine}-protos.h} and a source file @file{@var{machine}.c}
+(@pxref{Target Macros, , Target Description Macros and Functions}),
+possibly a target Makefile fragment @file{t-@var{machine}}
+(@pxref{Target Fragment, , The Target Makefile Fragment}), and maybe
+some other files.  The names of these files may be changed from the
+defaults given by explicit specifications in @file{config.gcc}.
+@item
+Entries in @file{config.gcc} (@pxref{System Config, , The
+@file{config.gcc} File}) for the systems with this target
+architecture.
+@item
+Documentation in @file{gcc/doc/invoke.texi} for any command-line
+options supported by this target (@pxref{Run-time Target, , Run-time
+Target Specification}).  This means both entries in the summary table
+of options and details of the individual options.
+@item
+Documentation in @file{gcc/doc/extend.texi} for any target-specific
+attributes supported (@pxref{Target Attributes, , Defining
+target-specific uses of @code{__attribute__}}), including where the
+same attribute is already supported on some targets, which are
+enumerated in the manual.
+@item
+Documentation in @file{gcc/doc/extend.texi} for any target-specific
+pragmas supported.
+@item
+Documentation in @file{gcc/doc/extend.texi} of any target-specific
+built-in functions supported.
+@item
+Documentation in @file{gcc/doc/md.texi} of any target-specific
+constraint letters (@pxref{Machine Constraints, , Constraints for
+Particular Machines}).
+@item
+A note in @file{gcc/doc/contrib.texi} under the person or people who
+contributed the target support.
+@item
+Entries in @file{gcc/doc/install.texi} for all target triplets
+supported with this target architecture, giving details of any special
+notes about installation for this target, or saying that there are no
+special notes if there are none.
+@item
+Possibly other support outside the @file{gcc} directory for runtime
+libraries.  FIXME: reference docs for this.  The libstdc++ porting
+manual needs to be installed as info for this to work, or to be a
+chapter of this manual.
+@end itemize
+
+If the back end is added to the official GCC CVS repository, the
+following are also necessary:
+
+@itemize @bullet
+@item
+An entry for the target architecture in @file{readings.html} on the
+GCC web site, with any relevant links.
+@item
+A news item about the contribution of support for that target
+architecture, in @file{index.html} on the GCC web site.
+@item
+Normally, one or more maintainers of that target listed in
+@file{MAINTAINERS}.  Some existing architectures may be unmaintained,
+but it would be unusual to add support for a target that does not have
+a maintainer when support is added.
+@end itemize
+
+@node Test Suites
+@section Test Suites
+
+GCC contains several test suites to help maintain compiler quality.
+Most of the runtime libraries and language front ends in GCC have test
+suites.  Currently only the C language test suites are documented
+here; FIXME: document the others.
+
+@menu
+* Test Idioms::  Idioms used in test suite code.
+* C Tests::      The C language test suites.
+@end menu
+
+@node Test Idioms
+@subsection Idioms Used in Test Suite Code
+
+In the @file{gcc.c-torture} test suites, test cases are commonly named
+after the date on which they were added.  This allows people to tell
+at a glance whether a test failure is because of a recently found bug
+that has not yet been fixed, or whether it may be a regression.  In
+other test suites, more descriptive names are used.  In general C test
+cases have a trailing @file{-@var{n}.c}, starting with @file{-1.c}, in
+case other test cases with similar names are added later.
+
+Test cases should use @code{abort ()} to indicate failure and
+@code{exit (0)} for success; on some targets these may be redefined to
+indicate failure and success in other ways.
+
+In the @file{gcc.dg} test suite, it is often necessary to test that an
+error is indeed a hard error and not just a warning---for example,
+where it is a constraint violation in the C standard, which must
+become an error with @option{-pedantic-errors}.  The following idiom,
+where the first line shown is line @var{line} of the file and the line
+that generates the error, is used for this:
+
+@smallexample
+/* @{ dg-bogus "warning" "warning in place of error" @} */
+/* @{ dg-error "@var{regexp}" "@var{message}" @{ target *-*-* @} @var{line} @} */
+@end smallexample
+
+It may be necessary to check that an expression is an integer constant
+expression and has a certain value.  To check that @code{@var{E}} has
+value @code{@var{V}}, an idiom similar to the following is used:
+
+@smallexample
+char x[((E) == (V) ? 1 : -1)];
+@end smallexample
+
+In @file{gcc.dg} tests, @code{__typeof__} is sometimes used to make
+assertions about the types of expressions.  See, for example,
+@file{gcc.dg/c99-condexpr-1.c}.  The more subtle uses depend on the
+exact rules for the types of conditional expressions in the C
+standard; see, for example, @file{gcc.dg/c99-intconst-1.c}.
+
+It is useful to be able to test that optimizations are being made
+properly.  This cannot be done in all cases, but it can be done where
+the optimization will lead to code being optimized away (for example,
+where flow analysis or alias analysis should show that certain code
+cannot be called) or to functions not being called because they have
+been expanded as built-in functions.  Such tests go in
+@file{gcc.c-torture/execute}.  Where code should be optimized away, a
+call to a nonexistent function such as @code{link_failure ()} may be
+inserted; a definition
+
+@smallexample
+#ifndef __OPTIMIZE__
+void
+link_failure (void)
+@{
+  abort ();
+@}
+#endif
+@end smallexample
+
+@noindent
+will also be needed so that linking still succeeds when the test is
+run without optimization.  When all calls to a built-in function
+should have been optimized and no calls to the non-built-in version of
+the function should remain, that function may be defined as
+@code{static} to call @code{abort ()} (although redeclaring a function
+as static may not work on all targets).
+
+FIXME: discuss non-C test suites here.
+
+@node C Tests
+@subsection C Language Test Suites
+
+GCC contains the following C language test suites, in the
+@file{gcc/testsuite} directory:
+
+@table @file
+@item gcc.c-torture/compat
+FIXME: describe this.
+
+This directory should probably not be used for new tests.
+@item gcc.c-torture/compile
+This test suite contains test cases that should compile, but do not
+need to link or run.  These test cases are compiled with several
+different combinations of optimization options.  All warnings are
+disabled for these test cases, so this directory is not suitable if
+you wish to test for the presence or absence of compiler warnings.
+While special options can be set, and tests disabled on specific
+platforms, by the use of @file{.x} files, mostly these test cases
+should not contain platform dependencies.  FIXME: discuss how defines
+such as @code{NO_LABEL_VALUES} and @code{STACK_SIZE} are used.
+@item gcc.c-torture/execute
+This test suite contains test cases that should compile, link and run;
+otherwise the same comments as for @file{gcc.c-torture/compile} apply.
+@item gcc.c-torture/unsorted
+FIXME: describe this.
+
+This directory should probably not be used for new tests.
+@item gcc.dg
+This test suite contains tests using the more modern @samp{dg} harness.
+Magic comments determine whether the file is preprocessed, compiled,
+linked or run.  In these tests, error and warning message texts are
+compared against expected texts or regular expressions given in
+comments.  These tests are run with the options @samp{-ansi -pedantic}
+unless other options are given in the test.  Except as noted below they
+are not run with multiple optimization options.
+@item gcc.dg/cpp
+This subdirectory contains tests of the preprocessor.
+@item gcc.dg/debug
+This subdirectory contains tests for debug formats.  Tests in this
+subdirectory are run for each debug format that the compiler supports.
+@item gcc.dg/format
+This subdirectory contains tests of the @option{-Wformat} format
+checking.  Tests in this directory are run with and without
+@option{-DWIDE}.
+@item gcc.dg/noncompile
+This subdirectory contains tests of code that should not compile and
+does not need any special compilation options.  They are run with
+multiple optimization options, since sometimes invalid code crashes
+the compiler with optimization.
+@item gcc.dg/special
+FIXME: describe this.
+@item gcc.c-torture/misc-tests
+FIXME: describe this, when it should be used for new tests and when it
+shouldn't.
+@end table
+
+FIXME: merge in @file{testsuite/README.gcc} and discuss the format of
+test cases and magic comments more.
diff --git a/contrib/gcc/doc/standards.texi b/contrib/gcc/doc/standards.texi
new file mode 100644
index 0000000..5d5ed0c
--- /dev/null
+++ b/contrib/gcc/doc/standards.texi
@@ -0,0 +1,178 @@
+@c Copyright (C) 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Standards
+@chapter Language Standards Supported by GCC
+@cindex C standard
+@cindex C standards
+@cindex ANSI C standard
+@cindex ANSI C
+@cindex ANSI C89
+@cindex C89
+@cindex ANSI X3.159-1989
+@cindex X3.159-1989
+@cindex ISO C standard
+@cindex ISO C
+@cindex ISO C89
+@cindex ISO C90
+@cindex ISO/IEC 9899
+@cindex ISO 9899
+@cindex C90
+@cindex ISO C94
+@cindex C94
+@cindex ISO C95
+@cindex C95
+@cindex ISO C99
+@cindex C99
+@cindex ISO C9X
+@cindex C9X
+@cindex Technical Corrigenda
+@cindex TC1
+@cindex Technical Corrigendum 1
+@cindex TC2
+@cindex Technical Corrigendum 2
+@cindex AMD1
+@cindex freestanding implementation
+@cindex freestanding environment
+@cindex hosted implementation
+@cindex hosted environment
+@findex __STDC_HOSTED__
+
+For each language compiled by GCC for which there is a standard, GCC
+attempts to follow one or more versions of that standard, possibly
+with some exceptions, and possibly with some extensions.
+
+GCC supports three versions of the C standard, although support for
+the most recent version is not yet complete.
+
+@opindex std
+@opindex ansi
+@opindex pedantic
+@opindex pedantic-errors
+The original ANSI C standard (X3.159-1989) was ratified in 1989 and
+published in 1990.  This standard was ratified as an ISO standard
+(ISO/IEC 9899:1990) later in 1990.  There were no technical
+differences between these publications, although the sections of the
+ANSI standard were renumbered and became clauses in the ISO standard.
+This standard, in both its forms, is commonly known as @dfn{C89}, or
+occasionally as @dfn{C90}, from the dates of ratification.  The ANSI
+standard, but not the ISO standard, also came with a Rationale
+document.  To select this standard in GCC, use one of the options
+@option{-ansi}, @option{-std=c89} or @option{-std=iso9899:1990}; to obtain
+all the diagnostics required by the standard, you should also specify
+@option{-pedantic} (or @option{-pedantic-errors} if you want them to be
+errors rather than warnings).  @xref{C Dialect Options,,Options
+Controlling C Dialect}.
+
+Errors in the 1990 ISO C standard were corrected in two Technical
+Corrigenda published in 1994 and 1996.  GCC does not support the
+uncorrected version.
+
+An amendment to the 1990 standard was published in 1995.  This
+amendment added digraphs and @code{__STDC_VERSION__} to the language,
+but otherwise concerned the library.  This amendment is commonly known
+as @dfn{AMD1}; the amended standard is sometimes known as @dfn{C94} or
+@dfn{C95}.  To select this standard in GCC, use the option
+@option{-std=iso9899:199409} (with, as for other standard versions,
+@option{-pedantic} to receive all required diagnostics).
+
+A new edition of the ISO C standard was published in 1999 as ISO/IEC
+9899:1999, and is commonly known as @dfn{C99}.  GCC has incomplete
+support for this standard version; see
+@uref{http://gcc.gnu.org/c99status.html} for details.  To select this
+standard, use @option{-std=c99} or @option{-std=iso9899:1999}.  (While in
+development, drafts of this standard version were referred to as
+@dfn{C9X}.)
+
+Errors in the 1999 ISO C standard were corrected in a Technical
+Corrigendum published in 2001.  GCC does not support the uncorrected
+version.
+
+@opindex traditional
+GCC also has some limited support for traditional (pre-ISO) C with the
+@option{-traditional} option.  This support may be of use for compiling
+some very old programs that have not been updated to ISO C, but should
+not be used for new programs.  It will not work with some modern C
+libraries such as the GNU C library.
+
+By default, GCC provides some extensions to the C language that on
+rare occasions conflict with the C standard.  @xref{C
+Extensions,,Extensions to the C Language Family}.  Use of the
+@option{-std} options listed above will disable these extensions where
+they conflict with the C standard version selected.  You may also
+select an extended version of the C language explicitly with
+@option{-std=gnu89} (for C89 with GNU extensions) or @option{-std=gnu99}
+(for C99 with GNU extensions).  The default, if no C language dialect
+options are given, is @option{-std=gnu89}; this will change to
+@option{-std=gnu99} in some future release when the C99 support is
+complete.  Some features that are part of the C99 standard are
+accepted as extensions in C89 mode.
+
+The ISO C standard defines (in clause 4) two classes of conforming
+implementation.  A @dfn{conforming hosted implementation} supports the
+whole standard including all the library facilities; a @dfn{conforming
+freestanding implementation} is only required to provide certain
+library facilities: those in @code{<float.h>}, @code{<limits.h>},
+@code{<stdarg.h>}, and @code{<stddef.h>}; since AMD1, also those in
+@code{<iso646.h>}; and in C99, also those in @code{<stdbool.h>} and
+@code{<stdint.h>}.  In addition, complex types, added in C99, are not
+required for freestanding implementations.  The standard also defines
+two environments for programs, a @dfn{freestanding environment},
+required of all implementations and which may not have library
+facilities beyond those required of freestanding implementations,
+where the handling of program startup and termination are
+implementation-defined, and a @dfn{hosted environment}, which is not
+required, in which all the library facilities are provided and startup
+is through a function @code{int main (void)} or @code{int main (int,
+char *[])}.  An OS kernel would be a freestanding environment; a
+program using the facilities of an operating system would normally be
+in a hosted implementation.
+
+@opindex ffreestanding
+GCC aims towards being usable as a conforming freestanding
+implementation, or as the compiler for a conforming hosted
+implementation.  By default, it will act as the compiler for a hosted
+implementation, defining @code{__STDC_HOSTED__} as @code{1} and
+presuming that when the names of ISO C functions are used, they have
+the semantics defined in the standard.  To make it act as a conforming
+freestanding implementation for a freestanding environment, use the
+option @option{-ffreestanding}; it will then define
+@code{__STDC_HOSTED__} to @code{0} and not make assumptions about the
+meanings of function names from the standard library.  To build an OS
+kernel, you may well still need to make your own arrangements for
+linking and startup.  @xref{C Dialect Options,,Options Controlling C
+Dialect}.
+
+GCC does not provide the library facilities required only of hosted
+implementations, nor yet all the facilities required by C99 of
+freestanding implementations; to use the facilities of a hosted
+environment, you will need to find them elsewhere (for example, in the
+GNU C library).  @xref{Standard Libraries,,Standard Libraries}.
+
+For references to Technical Corrigenda, Rationale documents and
+information concerning the history of C that is available online, see
+@uref{http://gcc.gnu.org/readings.html}
+
+@c FIXME: details of C++ standard.
+
+There is no formal written standard for Objective-C@.  The most
+authoritative manual is ``Object-Oriented Programming and the
+Objective-C Language'', available at a number of web sites;
+@uref{http://developer.apple.com/techpubs/macosx/Cocoa/ObjectiveC/} has a
+recent version, while @uref{http://www.toodarkpark.org/computers/objc/}
+is an older example.  @uref{http://www.gnustep.org} includes useful
+information as well.
+
+@xref{Top, GNAT Reference Manual, About This Guide, gnat_rm, 
+GNAT Reference Manual}, for information on standard
+conformance and compatibility of the Ada compiler.
+
+@xref{References,,Language Definition References, chill, GNU Chill},
+for details of the CHILL standard.
+
+@xref{Language,,The GNU Fortran Language, g77, Using and Porting GNU
+Fortran}, for details of the Fortran language supported by GCC@.
+
+@xref{Compatibility,,Compatibility with the Java Platform, gcj, GNU gcj},
+for details of compatibility between @code{gcj} and the Java Platform.
diff --git a/contrib/gcc/doc/tm.texi b/contrib/gcc/doc/tm.texi
new file mode 100644
index 0000000..e9797bf
--- /dev/null
+++ b/contrib/gcc/doc/tm.texi
@@ -0,0 +1,8614 @@
+@c Copyright (C) 1988,1989,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,2002
+@c Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Target Macros
+@chapter Target Description Macros and Functions
+@cindex machine description macros
+@cindex target description macros
+@cindex macros, target description
+@cindex @file{tm.h} macros
+
+In addition to the file @file{@var{machine}.md}, a machine description
+includes a C header file conventionally given the name
+@file{@var{machine}.h} and a C source file named @file{@var{machine}.c}.
+The header file defines numerous macros that convey the information
+about the target machine that does not fit into the scheme of the
+@file{.md} file.  The file @file{tm.h} should be a link to
+@file{@var{machine}.h}.  The header file @file{config.h} includes
+@file{tm.h} and most compiler source files include @file{config.h}.  The
+source file defines a variable @code{targetm}, which is a structure
+containing pointers to functions and data relating to the target
+machine.  @file{@var{machine}.c} should also contain their definitions,
+if they are not defined elsewhere in GCC, and other functions called
+through the macros defined in the @file{.h} file.
+
+@menu
+* Target Structure::    The @code{targetm} variable.
+* Driver::              Controlling how the driver runs the compilation passes.
+* Run-time Target::     Defining @samp{-m} options like @option{-m68000} and @option{-m68020}.
+* Per-Function Data::   Defining data structures for per-function information.
+* Storage Layout::      Defining sizes and alignments of data.
+* Type Layout::         Defining sizes and properties of basic user data types.
+* Escape Sequences::    Defining the value of target character escape sequences
+* Registers::           Naming and describing the hardware registers.
+* Register Classes::    Defining the classes of hardware registers.
+* Stack and Calling::   Defining which way the stack grows and by how much.
+* Varargs::		Defining the varargs macros.
+* Trampolines::         Code set up at run time to enter a nested function.
+* Library Calls::       Controlling how library routines are implicitly called.
+* Addressing Modes::    Defining addressing modes valid for memory operands.
+* Condition Code::      Defining how insns update the condition code.
+* Costs::               Defining relative costs of different operations.
+* Scheduling::          Adjusting the behavior of the instruction scheduler.
+* Sections::            Dividing storage into text, data, and other sections.
+* PIC::			Macros for position independent code.
+* Assembler Format::    Defining how to write insns and pseudo-ops to output.
+* Debugging Info::      Defining the format of debugging output.
+* Cross-compilation::   Handling floating point for cross-compilers.
+* Mode Switching::      Insertion of mode-switching instructions.
+* Target Attributes::   Defining target-specific uses of @code{__attribute__}.
+* Misc::                Everything else.
+@end menu
+
+@node Target Structure
+@section The Global @code{targetm} Variable
+@cindex target hooks
+@cindex target functions
+
+@deftypevar {struct gcc_target} targetm
+The target @file{.c} file must define the global @code{targetm} variable
+which contains pointers to functions and data relating to the target
+machine.  The variable is declared in @file{target.h};
+@file{target-def.h} defines the macro @code{TARGET_INITIALIZER} which is
+used to initialize the variable, and macros for the default initializers
+for elements of the structure.  The @file{.c} file should override those
+macros for which the default definition is inappropriate.  For example:
+@smallexample
+#include "target.h"
+#include "target-def.h"
+
+/* @r{Initialize the GCC target structure.}  */
+
+#undef TARGET_COMP_TYPE_ATTRIBUTES
+#define TARGET_COMP_TYPE_ATTRIBUTES @var{machine}_comp_type_attributes
+
+struct gcc_target targetm = TARGET_INITIALIZER;
+@end smallexample
+@end deftypevar
+
+Where a macro should be defined in the @file{.c} file in this manner to
+form part of the @code{targetm} structure, it is documented below as a
+``Target Hook'' with a prototype.  Many macros will change in future
+from being defined in the @file{.h} file to being part of the
+@code{targetm} structure.
+
+@node Driver
+@section Controlling the Compilation Driver, @file{gcc}
+@cindex driver
+@cindex controlling the compilation driver
+
+@c prevent bad page break with this line
+You can control the compilation driver.
+
+@table @code
+@findex SWITCH_TAKES_ARG
+@item SWITCH_TAKES_ARG (@var{char})
+A C expression which determines whether the option @option{-@var{char}}
+takes arguments.  The value should be the number of arguments that
+option takes--zero, for many options.
+
+By default, this macro is defined as
+@code{DEFAULT_SWITCH_TAKES_ARG}, which handles the standard options
+properly.  You need not define @code{SWITCH_TAKES_ARG} unless you
+wish to add additional options which take arguments.  Any redefinition
+should call @code{DEFAULT_SWITCH_TAKES_ARG} and then check for
+additional options.
+
+@findex WORD_SWITCH_TAKES_ARG
+@item WORD_SWITCH_TAKES_ARG (@var{name})
+A C expression which determines whether the option @option{-@var{name}}
+takes arguments.  The value should be the number of arguments that
+option takes--zero, for many options.  This macro rather than
+@code{SWITCH_TAKES_ARG} is used for multi-character option names.
+
+By default, this macro is defined as
+@code{DEFAULT_WORD_SWITCH_TAKES_ARG}, which handles the standard options
+properly.  You need not define @code{WORD_SWITCH_TAKES_ARG} unless you
+wish to add additional options which take arguments.  Any redefinition
+should call @code{DEFAULT_WORD_SWITCH_TAKES_ARG} and then check for
+additional options.
+
+@findex SWITCH_CURTAILS_COMPILATION
+@item SWITCH_CURTAILS_COMPILATION (@var{char})
+A C expression which determines whether the option @option{-@var{char}}
+stops compilation before the generation of an executable.  The value is
+boolean, nonzero if the option does stop an executable from being
+generated, zero otherwise.
+
+By default, this macro is defined as
+@code{DEFAULT_SWITCH_CURTAILS_COMPILATION}, which handles the standard
+options properly.  You need not define
+@code{SWITCH_CURTAILS_COMPILATION} unless you wish to add additional
+options which affect the generation of an executable.  Any redefinition
+should call @code{DEFAULT_SWITCH_CURTAILS_COMPILATION} and then check
+for additional options.
+
+@findex SWITCHES_NEED_SPACES
+@item SWITCHES_NEED_SPACES
+A string-valued C expression which enumerates the options for which
+the linker needs a space between the option and its argument.
+
+If this macro is not defined, the default value is @code{""}.
+
+@findex TARGET_OPTION_TRANSLATE_TABLE
+@item TARGET_OPTION_TRANSLATE_TABLE
+If defined, a list of pairs of strings, the first of which is a
+potential command line target to the @file{gcc} driver program, and the
+second of which is a space-separated (tabs and other whitespace are not
+supported) list of options with which to replace the first option.  The
+target defining this list is responsible for assuring that the results
+are valid.  Replacement options may not be the @code{--opt} style, they
+must be the @code{-opt} style.  It is the intention of this macro to
+provide a mechanism for substitution that affects the multilibs chosen,
+such as one option that enables many options, some of which select
+multilibs.  Example nonsensical definition, where @code{-malt-abi},
+@code{-EB}, and @code{-mspoo} cause different multilibs to be chosen:
+
+@example
+#define TARGET_OPTION_TRANSLATE_TABLE \
+@{ "-fast",   "-march=fast-foo -malt-abi -I/usr/fast-foo" @}, \
+@{ "-compat", "-EB -malign=4 -mspoo" @}
+@end example
+
+@findex CPP_SPEC
+@item CPP_SPEC
+A C string constant that tells the GCC driver program options to
+pass to CPP@.  It can also specify how to translate options you
+give to GCC into options for GCC to pass to the CPP@.
+
+Do not define this macro if it does not need to do anything.
+
+@findex CPLUSPLUS_CPP_SPEC
+@item CPLUSPLUS_CPP_SPEC
+This macro is just like @code{CPP_SPEC}, but is used for C++, rather
+than C@.  If you do not define this macro, then the value of
+@code{CPP_SPEC} (if any) will be used instead.
+
+@findex NO_BUILTIN_SIZE_TYPE
+@item NO_BUILTIN_SIZE_TYPE
+If this macro is defined, the preprocessor will not define the built-in macro
+@code{__SIZE_TYPE__}.  The macro @code{__SIZE_TYPE__} must then be defined
+by @code{CPP_SPEC} instead.
+
+This should be defined if @code{SIZE_TYPE} depends on target dependent flags
+which are not accessible to the preprocessor.  Otherwise, it should not
+be defined.
+
+@findex NO_BUILTIN_PTRDIFF_TYPE
+@item NO_BUILTIN_PTRDIFF_TYPE
+If this macro is defined, the preprocessor will not define the built-in macro
+@code{__PTRDIFF_TYPE__}.  The macro @code{__PTRDIFF_TYPE__} must then be
+defined by @code{CPP_SPEC} instead.
+
+This should be defined if @code{PTRDIFF_TYPE} depends on target dependent flags
+which are not accessible to the preprocessor.  Otherwise, it should not
+be defined.
+
+@findex NO_BUILTIN_WCHAR_TYPE
+@item NO_BUILTIN_WCHAR_TYPE
+If this macro is defined, the preprocessor will not define the built-in macro
+@code{__WCHAR_TYPE__}.  The macro @code{__WCHAR_TYPE__} must then be
+defined by @code{CPP_SPEC} instead.
+
+This should be defined if @code{WCHAR_TYPE} depends on target dependent flags
+which are not accessible to the preprocessor.  Otherwise, it should not
+be defined.
+
+@findex NO_BUILTIN_WINT_TYPE
+@item NO_BUILTIN_WINT_TYPE
+If this macro is defined, the preprocessor will not define the built-in macro
+@code{__WINT_TYPE__}.  The macro @code{__WINT_TYPE__} must then be
+defined by @code{CPP_SPEC} instead.
+
+This should be defined if @code{WINT_TYPE} depends on target dependent flags
+which are not accessible to the preprocessor.  Otherwise, it should not
+be defined.
+
+@findex SIGNED_CHAR_SPEC
+@item SIGNED_CHAR_SPEC
+A C string constant that tells the GCC driver program options to
+pass to CPP@.  By default, this macro is defined to pass the option
+@option{-D__CHAR_UNSIGNED__} to CPP if @code{char} will be treated as
+@code{unsigned char} by @code{cc1}.
+
+Do not define this macro unless you need to override the default
+definition.
+
+@findex CC1_SPEC
+@item CC1_SPEC
+A C string constant that tells the GCC driver program options to
+pass to @code{cc1}, @code{cc1plus}, @code{f771}, and the other language
+front ends.
+It can also specify how to translate options you give to GCC into options
+for GCC to pass to front ends.
+
+Do not define this macro if it does not need to do anything.
+
+@findex CC1PLUS_SPEC
+@item CC1PLUS_SPEC
+A C string constant that tells the GCC driver program options to
+pass to @code{cc1plus}.  It can also specify how to translate options you
+give to GCC into options for GCC to pass to the @code{cc1plus}.
+
+Do not define this macro if it does not need to do anything.
+Note that everything defined in CC1_SPEC is already passed to
+@code{cc1plus} so there is no need to duplicate the contents of
+CC1_SPEC in CC1PLUS_SPEC@.
+
+@findex ASM_SPEC
+@item ASM_SPEC
+A C string constant that tells the GCC driver program options to
+pass to the assembler.  It can also specify how to translate options
+you give to GCC into options for GCC to pass to the assembler.
+See the file @file{sun3.h} for an example of this.
+
+Do not define this macro if it does not need to do anything.
+
+@findex ASM_FINAL_SPEC
+@item ASM_FINAL_SPEC
+A C string constant that tells the GCC driver program how to
+run any programs which cleanup after the normal assembler.
+Normally, this is not needed.  See the file @file{mips.h} for
+an example of this.
+
+Do not define this macro if it does not need to do anything.
+
+@findex LINK_SPEC
+@item LINK_SPEC
+A C string constant that tells the GCC driver program options to
+pass to the linker.  It can also specify how to translate options you
+give to GCC into options for GCC to pass to the linker.
+
+Do not define this macro if it does not need to do anything.
+
+@findex LIB_SPEC
+@item LIB_SPEC
+Another C string constant used much like @code{LINK_SPEC}.  The difference
+between the two is that @code{LIB_SPEC} is used at the end of the
+command given to the linker.
+
+If this macro is not defined, a default is provided that
+loads the standard C library from the usual place.  See @file{gcc.c}.
+
+@findex LIBGCC_SPEC
+@item LIBGCC_SPEC
+Another C string constant that tells the GCC driver program
+how and when to place a reference to @file{libgcc.a} into the
+linker command line.  This constant is placed both before and after
+the value of @code{LIB_SPEC}.
+
+If this macro is not defined, the GCC driver provides a default that
+passes the string @option{-lgcc} to the linker.
+
+@findex STARTFILE_SPEC
+@item STARTFILE_SPEC
+Another C string constant used much like @code{LINK_SPEC}.  The
+difference between the two is that @code{STARTFILE_SPEC} is used at
+the very beginning of the command given to the linker.
+
+If this macro is not defined, a default is provided that loads the
+standard C startup file from the usual place.  See @file{gcc.c}.
+
+@findex ENDFILE_SPEC
+@item ENDFILE_SPEC
+Another C string constant used much like @code{LINK_SPEC}.  The
+difference between the two is that @code{ENDFILE_SPEC} is used at
+the very end of the command given to the linker.
+
+Do not define this macro if it does not need to do anything.
+
+@findex THREAD_MODEL_SPEC
+@item THREAD_MODEL_SPEC
+GCC @code{-v} will print the thread model GCC was configured to use.
+However, this doesn't work on platforms that are multilibbed on thread
+models, such as AIX 4.3.  On such platforms, define
+@code{THREAD_MODEL_SPEC} such that it evaluates to a string without
+blanks that names one of the recognized thread models.  @code{%*}, the
+default value of this macro, will expand to the value of
+@code{thread_file} set in @file{config.gcc}.
+
+@findex EXTRA_SPECS
+@item EXTRA_SPECS
+Define this macro to provide additional specifications to put in the
+@file{specs} file that can be used in various specifications like
+@code{CC1_SPEC}.
+
+The definition should be an initializer for an array of structures,
+containing a string constant, that defines the specification name, and a
+string constant that provides the specification.
+
+Do not define this macro if it does not need to do anything.
+
+@code{EXTRA_SPECS} is useful when an architecture contains several
+related targets, which have various @code{@dots{}_SPECS} which are similar
+to each other, and the maintainer would like one central place to keep
+these definitions.
+
+For example, the PowerPC System V.4 targets use @code{EXTRA_SPECS} to
+define either @code{_CALL_SYSV} when the System V calling sequence is
+used or @code{_CALL_AIX} when the older AIX-based calling sequence is
+used.
+
+The @file{config/rs6000/rs6000.h} target file defines:
+
+@example
+#define EXTRA_SPECS \
+  @{ "cpp_sysv_default", CPP_SYSV_DEFAULT @},
+
+#define CPP_SYS_DEFAULT ""
+@end example
+
+The @file{config/rs6000/sysv.h} target file defines:
+@smallexample
+#undef CPP_SPEC
+#define CPP_SPEC \
+"%@{posix: -D_POSIX_SOURCE @} \
+%@{mcall-sysv: -D_CALL_SYSV @} %@{mcall-aix: -D_CALL_AIX @} \
+%@{!mcall-sysv: %@{!mcall-aix: %(cpp_sysv_default) @}@} \
+%@{msoft-float: -D_SOFT_FLOAT@} %@{mcpu=403: -D_SOFT_FLOAT@}"
+
+#undef CPP_SYSV_DEFAULT
+#define CPP_SYSV_DEFAULT "-D_CALL_SYSV"
+@end smallexample
+
+while the @file{config/rs6000/eabiaix.h} target file defines
+@code{CPP_SYSV_DEFAULT} as:
+
+@smallexample
+#undef CPP_SYSV_DEFAULT
+#define CPP_SYSV_DEFAULT "-D_CALL_AIX"
+@end smallexample
+
+@findex LINK_LIBGCC_SPECIAL
+@item LINK_LIBGCC_SPECIAL
+Define this macro if the driver program should find the library
+@file{libgcc.a} itself and should not pass @option{-L} options to the
+linker.  If you do not define this macro, the driver program will pass
+the argument @option{-lgcc} to tell the linker to do the search and will
+pass @option{-L} options to it.
+
+@findex LINK_LIBGCC_SPECIAL_1
+@item LINK_LIBGCC_SPECIAL_1
+Define this macro if the driver program should find the library
+@file{libgcc.a}.  If you do not define this macro, the driver program will pass
+the argument @option{-lgcc} to tell the linker to do the search.
+This macro is similar to @code{LINK_LIBGCC_SPECIAL}, except that it does
+not affect @option{-L} options.
+
+@findex LINK_COMMAND_SPEC
+@item LINK_COMMAND_SPEC
+A C string constant giving the complete command line need to execute the
+linker.  When you do this, you will need to update your port each time a
+change is made to the link command line within @file{gcc.c}.  Therefore,
+define this macro only if you need to completely redefine the command
+line for invoking the linker and there is no other way to accomplish
+the effect you need.
+
+@findex LINK_ELIMINATE_DUPLICATE_LDIRECTORIES
+@item LINK_ELIMINATE_DUPLICATE_LDIRECTORIES
+A nonzero value causes @command{collect2} to remove duplicate @option{-L@var{directory}} search
+directories from linking commands.  Do not give it a nonzero value if
+removing duplicate search directories changes the linker's semantics.
+
+@findex MULTILIB_DEFAULTS
+@item MULTILIB_DEFAULTS
+Define this macro as a C expression for the initializer of an array of
+string to tell the driver program which options are defaults for this
+target and thus do not need to be handled specially when using
+@code{MULTILIB_OPTIONS}.
+
+Do not define this macro if @code{MULTILIB_OPTIONS} is not defined in
+the target makefile fragment or if none of the options listed in
+@code{MULTILIB_OPTIONS} are set by default.
+@xref{Target Fragment}.
+
+@findex RELATIVE_PREFIX_NOT_LINKDIR
+@item RELATIVE_PREFIX_NOT_LINKDIR
+Define this macro to tell @code{gcc} that it should only translate
+a @option{-B} prefix into a @option{-L} linker option if the prefix
+indicates an absolute file name.
+
+@findex STANDARD_EXEC_PREFIX
+@item STANDARD_EXEC_PREFIX
+Define this macro as a C string constant if you wish to override the
+standard choice of @file{/usr/local/lib/gcc-lib/} as the default prefix to
+try when searching for the executable files of the compiler.
+
+@findex MD_EXEC_PREFIX
+@item MD_EXEC_PREFIX
+If defined, this macro is an additional prefix to try after
+@code{STANDARD_EXEC_PREFIX}.  @code{MD_EXEC_PREFIX} is not searched
+when the @option{-b} option is used, or the compiler is built as a cross
+compiler.  If you define @code{MD_EXEC_PREFIX}, then be sure to add it
+to the list of directories used to find the assembler in @file{configure.in}.
+
+@findex STANDARD_STARTFILE_PREFIX
+@item STANDARD_STARTFILE_PREFIX
+Define this macro as a C string constant if you wish to override the
+standard choice of @file{/usr/local/lib/} as the default prefix to
+try when searching for startup files such as @file{crt0.o}.
+
+@findex MD_STARTFILE_PREFIX
+@item MD_STARTFILE_PREFIX
+If defined, this macro supplies an additional prefix to try after the
+standard prefixes.  @code{MD_EXEC_PREFIX} is not searched when the
+@option{-b} option is used, or when the compiler is built as a cross
+compiler.
+
+@findex MD_STARTFILE_PREFIX_1
+@item MD_STARTFILE_PREFIX_1
+If defined, this macro supplies yet another prefix to try after the
+standard prefixes.  It is not searched when the @option{-b} option is
+used, or when the compiler is built as a cross compiler.
+
+@findex INIT_ENVIRONMENT
+@item INIT_ENVIRONMENT
+Define this macro as a C string constant if you wish to set environment
+variables for programs called by the driver, such as the assembler and
+loader.  The driver passes the value of this macro to @code{putenv} to
+initialize the necessary environment variables.
+
+@findex LOCAL_INCLUDE_DIR
+@item LOCAL_INCLUDE_DIR
+Define this macro as a C string constant if you wish to override the
+standard choice of @file{/usr/local/include} as the default prefix to
+try when searching for local header files.  @code{LOCAL_INCLUDE_DIR}
+comes before @code{SYSTEM_INCLUDE_DIR} in the search order.
+
+Cross compilers do not search either @file{/usr/local/include} or its
+replacement.
+
+@findex MODIFY_TARGET_NAME
+@item MODIFY_TARGET_NAME
+Define this macro if you with to define command-line switches that modify the
+default target name
+
+For each switch, you can include a string to be appended to the first
+part of the configuration name or a string to be deleted from the
+configuration name, if present.  The definition should be an initializer
+for an array of structures.  Each array element should have three
+elements: the switch name (a string constant, including the initial
+dash), one of the enumeration codes @code{ADD} or @code{DELETE} to
+indicate whether the string should be inserted or deleted, and the string
+to be inserted or deleted (a string constant).
+
+For example, on a machine where @samp{64} at the end of the
+configuration name denotes a 64-bit target and you want the @option{-32}
+and @option{-64} switches to select between 32- and 64-bit targets, you would
+code
+
+@smallexample
+#define MODIFY_TARGET_NAME \
+  @{ @{ "-32", DELETE, "64"@}, \
+     @{"-64", ADD, "64"@}@}
+@end smallexample
+
+
+@findex SYSTEM_INCLUDE_DIR
+@item SYSTEM_INCLUDE_DIR
+Define this macro as a C string constant if you wish to specify a
+system-specific directory to search for header files before the standard
+directory.  @code{SYSTEM_INCLUDE_DIR} comes before
+@code{STANDARD_INCLUDE_DIR} in the search order.
+
+Cross compilers do not use this macro and do not search the directory
+specified.
+
+@findex STANDARD_INCLUDE_DIR
+@item STANDARD_INCLUDE_DIR
+Define this macro as a C string constant if you wish to override the
+standard choice of @file{/usr/include} as the default prefix to
+try when searching for header files.
+
+Cross compilers do not use this macro and do not search either
+@file{/usr/include} or its replacement.
+
+@findex STANDARD_INCLUDE_COMPONENT
+@item STANDARD_INCLUDE_COMPONENT
+The ``component'' corresponding to @code{STANDARD_INCLUDE_DIR}.
+See @code{INCLUDE_DEFAULTS}, below, for the description of components.
+If you do not define this macro, no component is used.
+
+@findex INCLUDE_DEFAULTS
+@item INCLUDE_DEFAULTS
+Define this macro if you wish to override the entire default search path
+for include files.  For a native compiler, the default search path
+usually consists of @code{GCC_INCLUDE_DIR}, @code{LOCAL_INCLUDE_DIR},
+@code{SYSTEM_INCLUDE_DIR}, @code{GPLUSPLUS_INCLUDE_DIR}, and
+@code{STANDARD_INCLUDE_DIR}.  In addition, @code{GPLUSPLUS_INCLUDE_DIR}
+and @code{GCC_INCLUDE_DIR} are defined automatically by @file{Makefile},
+and specify private search areas for GCC@.  The directory
+@code{GPLUSPLUS_INCLUDE_DIR} is used only for C++ programs.
+
+The definition should be an initializer for an array of structures.
+Each array element should have four elements: the directory name (a
+string constant), the component name (also a string constant), a flag
+for C++-only directories,
+and a flag showing that the includes in the directory don't need to be
+wrapped in @code{extern @samp{C}} when compiling C++.  Mark the end of
+the array with a null element.
+
+The component name denotes what GNU package the include file is part of,
+if any, in all upper-case letters.  For example, it might be @samp{GCC}
+or @samp{BINUTILS}.  If the package is part of a vendor-supplied
+operating system, code the component name as @samp{0}.
+
+For example, here is the definition used for VAX/VMS:
+
+@example
+#define INCLUDE_DEFAULTS \
+@{                                       \
+  @{ "GNU_GXX_INCLUDE:", "G++", 1, 1@},   \
+  @{ "GNU_CC_INCLUDE:", "GCC", 0, 0@},    \
+  @{ "SYS$SYSROOT:[SYSLIB.]", 0, 0, 0@},  \
+  @{ ".", 0, 0, 0@},                      \
+  @{ 0, 0, 0, 0@}                         \
+@}
+@end example
+@end table
+
+Here is the order of prefixes tried for exec files:
+
+@enumerate
+@item
+Any prefixes specified by the user with @option{-B}.
+
+@item
+The environment variable @code{GCC_EXEC_PREFIX}, if any.
+
+@item
+The directories specified by the environment variable @code{COMPILER_PATH}.
+
+@item
+The macro @code{STANDARD_EXEC_PREFIX}.
+
+@item
+@file{/usr/lib/gcc/}.
+
+@item
+The macro @code{MD_EXEC_PREFIX}, if any.
+@end enumerate
+
+Here is the order of prefixes tried for startfiles:
+
+@enumerate
+@item
+Any prefixes specified by the user with @option{-B}.
+
+@item
+The environment variable @code{GCC_EXEC_PREFIX}, if any.
+
+@item
+The directories specified by the environment variable @code{LIBRARY_PATH}
+(or port-specific name; native only, cross compilers do not use this).
+
+@item
+The macro @code{STANDARD_EXEC_PREFIX}.
+
+@item
+@file{/usr/lib/gcc/}.
+
+@item
+The macro @code{MD_EXEC_PREFIX}, if any.
+
+@item
+The macro @code{MD_STARTFILE_PREFIX}, if any.
+
+@item
+The macro @code{STANDARD_STARTFILE_PREFIX}.
+
+@item
+@file{/lib/}.
+
+@item
+@file{/usr/lib/}.
+@end enumerate
+
+@node Run-time Target
+@section Run-time Target Specification
+@cindex run-time target specification
+@cindex predefined macros
+@cindex target specifications
+
+@c prevent bad page break with this line
+Here are run-time target specifications.
+
+@table @code
+@findex CPP_PREDEFINES
+@item CPP_PREDEFINES
+Define this to be a string constant containing @option{-D} options to
+define the predefined macros that identify this machine and system.
+These macros will be predefined unless the @option{-ansi} option (or a
+@option{-std} option for strict ISO C conformance) is specified.
+
+In addition, a parallel set of macros are predefined, whose names are
+made by appending @samp{__} at the beginning and at the end.  These
+@samp{__} macros are permitted by the ISO standard, so they are
+predefined regardless of whether @option{-ansi} or a @option{-std} option
+is specified.
+
+For example, on the Sun, one can use the following value:
+
+@smallexample
+"-Dmc68000 -Dsun -Dunix"
+@end smallexample
+
+The result is to define the macros @code{__mc68000__}, @code{__sun__}
+and @code{__unix__} unconditionally, and the macros @code{mc68000},
+@code{sun} and @code{unix} provided @option{-ansi} is not specified.
+
+@findex extern int target_flags
+@item extern int target_flags;
+This declaration should be present.
+
+@cindex optional hardware or system features
+@cindex features, optional, in system conventions
+@item TARGET_@dots{}
+This series of macros is to allow compiler command arguments to
+enable or disable the use of optional features of the target machine.
+For example, one machine description serves both the 68000 and
+the 68020; a command argument tells the compiler whether it should
+use 68020-only instructions or not.  This command argument works
+by means of a macro @code{TARGET_68020} that tests a bit in
+@code{target_flags}.
+
+Define a macro @code{TARGET_@var{featurename}} for each such option.
+Its definition should test a bit in @code{target_flags}.  It is
+recommended that a helper macro @code{TARGET_MASK_@var{featurename}}
+is defined for each bit-value to test, and used in
+@code{TARGET_@var{featurename}} and @code{TARGET_SWITCHES}.  For
+example:
+
+@smallexample
+#define TARGET_MASK_68020 1
+#define TARGET_68020 (target_flags & TARGET_MASK_68020)
+@end smallexample
+
+One place where these macros are used is in the condition-expressions
+of instruction patterns.  Note how @code{TARGET_68020} appears
+frequently in the 68000 machine description file, @file{m68k.md}.
+Another place they are used is in the definitions of the other
+macros in the @file{@var{machine}.h} file.
+
+@findex TARGET_SWITCHES
+@item TARGET_SWITCHES
+This macro defines names of command options to set and clear
+bits in @code{target_flags}.  Its definition is an initializer
+with a subgrouping for each command option.
+
+Each subgrouping contains a string constant, that defines the option
+name, a number, which contains the bits to set in
+@code{target_flags}, and a second string which is the description
+displayed by @option{--help}.  If the number is negative then the bits specified
+by the number are cleared instead of being set.  If the description
+string is present but empty, then no help information will be displayed
+for that option, but it will not count as an undocumented option.  The
+actual option name is made by appending @samp{-m} to the specified name.
+Non-empty description strings should be marked with @code{N_(@dots{})} for
+@command{xgettext}.  In addition to the description for @option{--help},
+more detailed documentation for each option should be added to
+@file{invoke.texi}.
+
+One of the subgroupings should have a null string.  The number in
+this grouping is the default value for @code{target_flags}.  Any
+target options act starting with that value.
+
+Here is an example which defines @option{-m68000} and @option{-m68020}
+with opposite meanings, and picks the latter as the default:
+
+@smallexample
+#define TARGET_SWITCHES \
+  @{ @{ "68020", TARGET_MASK_68020, "" @},      \
+    @{ "68000", -TARGET_MASK_68020, \
+      N_("Compile for the 68000") @}, \
+    @{ "", TARGET_MASK_68020, "" @}@}
+@end smallexample
+
+@findex TARGET_OPTIONS
+@item TARGET_OPTIONS
+This macro is similar to @code{TARGET_SWITCHES} but defines names of command
+options that have values.  Its definition is an initializer with a
+subgrouping for each command option.
+
+Each subgrouping contains a string constant, that defines the fixed part
+of the option name, the address of a variable, and a description string
+(which should again be marked with @code{N_(@dots{})}).
+The variable, type @code{char *}, is set to the variable part of the
+given option if the fixed part matches.  The actual option name is made
+by appending @samp{-m} to the specified name.  Again, each option should
+also be documented in @file{invoke.texi}.
+
+Here is an example which defines @option{-mshort-data-@var{number}}.  If the
+given option is @option{-mshort-data-512}, the variable @code{m88k_short_data}
+will be set to the string @code{"512"}.
+
+@smallexample
+extern char *m88k_short_data;
+#define TARGET_OPTIONS \
+ @{ @{ "short-data-", &m88k_short_data, \
+     N_("Specify the size of the short data section") @} @}
+@end smallexample
+
+@findex TARGET_VERSION
+@item TARGET_VERSION
+This macro is a C statement to print on @code{stderr} a string
+describing the particular machine description choice.  Every machine
+description should define @code{TARGET_VERSION}.  For example:
+
+@smallexample
+#ifdef MOTOROLA
+#define TARGET_VERSION \
+  fprintf (stderr, " (68k, Motorola syntax)");
+#else
+#define TARGET_VERSION \
+  fprintf (stderr, " (68k, MIT syntax)");
+#endif
+@end smallexample
+
+@findex OVERRIDE_OPTIONS
+@item OVERRIDE_OPTIONS
+Sometimes certain combinations of command options do not make sense on
+a particular target machine.  You can define a macro
+@code{OVERRIDE_OPTIONS} to take account of this.  This macro, if
+defined, is executed once just after all the command options have been
+parsed.
+
+Don't use this macro to turn on various extra optimizations for
+@option{-O}.  That is what @code{OPTIMIZATION_OPTIONS} is for.
+
+@findex OPTIMIZATION_OPTIONS
+@item OPTIMIZATION_OPTIONS (@var{level}, @var{size})
+Some machines may desire to change what optimizations are performed for
+various optimization levels.   This macro, if defined, is executed once
+just after the optimization level is determined and before the remainder
+of the command options have been parsed.  Values set in this macro are
+used as the default values for the other command line options.
+
+@var{level} is the optimization level specified; 2 if @option{-O2} is
+specified, 1 if @option{-O} is specified, and 0 if neither is specified.
+
+@var{size} is nonzero if @option{-Os} is specified and zero otherwise.
+
+You should not use this macro to change options that are not
+machine-specific.  These should uniformly selected by the same
+optimization level on all supported machines.  Use this macro to enable
+machine-specific optimizations.
+
+@strong{Do not examine @code{write_symbols} in
+this macro!} The debugging options are not supposed to alter the
+generated code.
+
+@findex CAN_DEBUG_WITHOUT_FP
+@item CAN_DEBUG_WITHOUT_FP
+Define this macro if debugging can be performed even without a frame
+pointer.  If this macro is defined, GCC will turn on the
+@option{-fomit-frame-pointer} option whenever @option{-O} is specified.
+@end table
+
+@node Per-Function Data
+@section Defining data structures for per-function information.
+@cindex per-function data
+@cindex data structures
+
+If the target needs to store information on a per-function basis, GCC
+provides a macro and a couple of variables to allow this.  Note, just
+using statics to store the information is a bad idea, since GCC supports
+nested functions, so you can be halfway through encoding one function
+when another one comes along.
+
+GCC defines a data structure called @code{struct function} which
+contains all of the data specific to an individual function.  This
+structure contains a field called @code{machine} whose type is
+@code{struct machine_function *}, which can be used by targets to point
+to their own specific data.
+
+If a target needs per-function specific data it should define the type
+@code{struct machine_function} and also the macro
+@code{INIT_EXPANDERS}.  This macro should be used to initialize some or
+all of the function pointers @code{init_machine_status},
+@code{free_machine_status} and @code{mark_machine_status}.  These
+pointers are explained below.
+
+One typical use of per-function, target specific data is to create an
+RTX to hold the register containing the function's return address.  This
+RTX can then be used to implement the @code{__builtin_return_address}
+function, for level 0.
+
+Note---earlier implementations of GCC used a single data area to hold
+all of the per-function information.  Thus when processing of a nested
+function began the old per-function data had to be pushed onto a
+stack, and when the processing was finished, it had to be popped off the
+stack.  GCC used to provide function pointers called
+@code{save_machine_status} and @code{restore_machine_status} to handle
+the saving and restoring of the target specific information.  Since the
+single data area approach is no longer used, these pointers are no
+longer supported.
+
+The macro and function pointers are described below.
+
+@table @code
+@findex INIT_EXPANDERS
+@item   INIT_EXPANDERS
+Macro called to initialize any target specific information.  This macro
+is called once per function, before generation of any RTL has begun.
+The intention of this macro is to allow the initialization of the
+function pointers below.
+
+@findex init_machine_status
+@item   init_machine_status
+This is a @code{void (*)(struct function *)} function pointer.  If this
+pointer is non-@code{NULL} it will be called once per function, before function
+compilation starts, in order to allow the target to perform any target
+specific initialization of the @code{struct function} structure.  It is
+intended that this would be used to initialize the @code{machine} of
+that structure.
+
+@findex free_machine_status
+@item   free_machine_status
+This is a @code{void (*)(struct function *)} function pointer.  If this
+pointer is non-@code{NULL} it will be called once per function, after the
+function has been compiled, in order to allow any memory allocated
+during the @code{init_machine_status} function call to be freed.
+
+@findex mark_machine_status
+@item   mark_machine_status
+This is a @code{void (*)(struct function *)} function pointer.  If this
+pointer is non-@code{NULL} it will be called once per function in order to mark
+any data items in the @code{struct machine_function} structure which
+need garbage collection.
+
+@end table
+
+@node Storage Layout
+@section Storage Layout
+@cindex storage layout
+
+Note that the definitions of the macros in this table which are sizes or
+alignments measured in bits do not need to be constant.  They can be C
+expressions that refer to static variables, such as the @code{target_flags}.
+@xref{Run-time Target}.
+
+@table @code
+@findex BITS_BIG_ENDIAN
+@item BITS_BIG_ENDIAN
+Define this macro to have the value 1 if the most significant bit in a
+byte has the lowest number; otherwise define it to have the value zero.
+This means that bit-field instructions count from the most significant
+bit.  If the machine has no bit-field instructions, then this must still
+be defined, but it doesn't matter which value it is defined to.  This
+macro need not be a constant.
+
+This macro does not affect the way structure fields are packed into
+bytes or words; that is controlled by @code{BYTES_BIG_ENDIAN}.
+
+@findex BYTES_BIG_ENDIAN
+@item BYTES_BIG_ENDIAN
+Define this macro to have the value 1 if the most significant byte in a
+word has the lowest number.  This macro need not be a constant.
+
+@findex WORDS_BIG_ENDIAN
+@item WORDS_BIG_ENDIAN
+Define this macro to have the value 1 if, in a multiword object, the
+most significant word has the lowest number.  This applies to both
+memory locations and registers; GCC fundamentally assumes that the
+order of words in memory is the same as the order in registers.  This
+macro need not be a constant.
+
+@findex LIBGCC2_WORDS_BIG_ENDIAN
+@item LIBGCC2_WORDS_BIG_ENDIAN
+Define this macro if @code{WORDS_BIG_ENDIAN} is not constant.  This must be a
+constant value with the same meaning as @code{WORDS_BIG_ENDIAN}, which will be
+used only when compiling @file{libgcc2.c}.  Typically the value will be set
+based on preprocessor defines.
+
+@findex FLOAT_WORDS_BIG_ENDIAN
+@item FLOAT_WORDS_BIG_ENDIAN
+Define this macro to have the value 1 if @code{DFmode}, @code{XFmode} or
+@code{TFmode} floating point numbers are stored in memory with the word
+containing the sign bit at the lowest address; otherwise define it to
+have the value 0.  This macro need not be a constant.
+
+You need not define this macro if the ordering is the same as for
+multi-word integers.
+
+@findex BITS_PER_UNIT
+@item BITS_PER_UNIT
+Define this macro to be the number of bits in an addressable storage
+unit (byte); normally 8.
+
+@findex BITS_PER_WORD
+@item BITS_PER_WORD
+Number of bits in a word; normally 32.
+
+@findex MAX_BITS_PER_WORD
+@item MAX_BITS_PER_WORD
+Maximum number of bits in a word.  If this is undefined, the default is
+@code{BITS_PER_WORD}.  Otherwise, it is the constant value that is the
+largest value that @code{BITS_PER_WORD} can have at run-time.
+
+@findex UNITS_PER_WORD
+@item UNITS_PER_WORD
+Number of storage units in a word; normally 4.
+
+@findex MIN_UNITS_PER_WORD
+@item MIN_UNITS_PER_WORD
+Minimum number of units in a word.  If this is undefined, the default is
+@code{UNITS_PER_WORD}.  Otherwise, it is the constant value that is the
+smallest value that @code{UNITS_PER_WORD} can have at run-time.
+
+@findex POINTER_SIZE
+@item POINTER_SIZE
+Width of a pointer, in bits.  You must specify a value no wider than the
+width of @code{Pmode}.  If it is not equal to the width of @code{Pmode},
+you must define @code{POINTERS_EXTEND_UNSIGNED}.
+
+@findex POINTERS_EXTEND_UNSIGNED
+@item POINTERS_EXTEND_UNSIGNED
+A C expression whose value is greater than zero if pointers that need to be
+extended from being @code{POINTER_SIZE} bits wide to @code{Pmode} are to
+be zero-extended and zero if they are to be sign-extended.  If the value
+is less then zero then there must be an "ptr_extend" instruction that
+extends a pointer from @code{POINTER_SIZE} to @code{Pmode}.
+
+You need not define this macro if the @code{POINTER_SIZE} is equal
+to the width of @code{Pmode}.
+
+@findex PROMOTE_MODE
+@item PROMOTE_MODE (@var{m}, @var{unsignedp}, @var{type})
+A macro to update @var{m} and @var{unsignedp} when an object whose type
+is @var{type} and which has the specified mode and signedness is to be
+stored in a register.  This macro is only called when @var{type} is a
+scalar type.
+
+On most RISC machines, which only have operations that operate on a full
+register, define this macro to set @var{m} to @code{word_mode} if
+@var{m} is an integer mode narrower than @code{BITS_PER_WORD}.  In most
+cases, only integer modes should be widened because wider-precision
+floating-point operations are usually more expensive than their narrower
+counterparts.
+
+For most machines, the macro definition does not change @var{unsignedp}.
+However, some machines, have instructions that preferentially handle
+either signed or unsigned quantities of certain modes.  For example, on
+the DEC Alpha, 32-bit loads from memory and 32-bit add instructions
+sign-extend the result to 64 bits.  On such machines, set
+@var{unsignedp} according to which kind of extension is more efficient.
+
+Do not define this macro if it would never modify @var{m}.
+
+@findex PROMOTE_FUNCTION_ARGS
+@item PROMOTE_FUNCTION_ARGS
+Define this macro if the promotion described by @code{PROMOTE_MODE}
+should also be done for outgoing function arguments.
+
+@findex PROMOTE_FUNCTION_RETURN
+@item PROMOTE_FUNCTION_RETURN
+Define this macro if the promotion described by @code{PROMOTE_MODE}
+should also be done for the return value of functions.
+
+If this macro is defined, @code{FUNCTION_VALUE} must perform the same
+promotions done by @code{PROMOTE_MODE}.
+
+@findex PROMOTE_FOR_CALL_ONLY
+@item PROMOTE_FOR_CALL_ONLY
+Define this macro if the promotion described by @code{PROMOTE_MODE}
+should @emph{only} be performed for outgoing function arguments or
+function return values, as specified by @code{PROMOTE_FUNCTION_ARGS}
+and @code{PROMOTE_FUNCTION_RETURN}, respectively.
+
+@findex PARM_BOUNDARY
+@item PARM_BOUNDARY
+Normal alignment required for function parameters on the stack, in
+bits.  All stack parameters receive at least this much alignment
+regardless of data type.  On most machines, this is the same as the
+size of an integer.
+
+@findex STACK_BOUNDARY
+@item STACK_BOUNDARY
+Define this macro to the minimum alignment enforced by hardware for the
+stack pointer on this machine.  The definition is a C expression for the
+desired alignment (measured in bits).  This value is used as a default
+if @code{PREFERRED_STACK_BOUNDARY} is not defined.  On most machines,
+this should be the same as @code{PARM_BOUNDARY}.
+
+@findex PREFERRED_STACK_BOUNDARY
+@item PREFERRED_STACK_BOUNDARY
+Define this macro if you wish to preserve a certain alignment for the
+stack pointer, greater than what the hardware enforces.  The definition
+is a C expression for the desired alignment (measured in bits).  This
+macro must evaluate to a value equal to or larger than
+@code{STACK_BOUNDARY}.
+
+@findex FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN
+@item FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN
+A C expression that evaluates true if @code{PREFERRED_STACK_BOUNDARY} is
+not guaranteed by the runtime and we should emit code to align the stack
+at the beginning of @code{main}.
+
+@cindex @code{PUSH_ROUNDING}, interaction with @code{PREFERRED_STACK_BOUNDARY}
+If @code{PUSH_ROUNDING} is not defined, the stack will always be aligned
+to the specified boundary.  If @code{PUSH_ROUNDING} is defined and specifies
+a less strict alignment than @code{PREFERRED_STACK_BOUNDARY}, the stack may
+be momentarily unaligned while pushing arguments.
+
+@findex FUNCTION_BOUNDARY
+@item FUNCTION_BOUNDARY
+Alignment required for a function entry point, in bits.
+
+@findex BIGGEST_ALIGNMENT
+@item BIGGEST_ALIGNMENT
+Biggest alignment that any data type can require on this machine, in bits.
+
+@findex MINIMUM_ATOMIC_ALIGNMENT
+@item MINIMUM_ATOMIC_ALIGNMENT
+If defined, the smallest alignment, in bits, that can be given to an
+object that can be referenced in one operation, without disturbing any
+nearby object.  Normally, this is @code{BITS_PER_UNIT}, but may be larger
+on machines that don't have byte or half-word store operations.
+
+@findex BIGGEST_FIELD_ALIGNMENT
+@item BIGGEST_FIELD_ALIGNMENT
+Biggest alignment that any structure or union field can require on this
+machine, in bits.  If defined, this overrides @code{BIGGEST_ALIGNMENT} for
+structure and union fields only, unless the field alignment has been set
+by the @code{__attribute__ ((aligned (@var{n})))} construct.
+
+@findex ADJUST_FIELD_ALIGN
+@item ADJUST_FIELD_ALIGN (@var{field}, @var{computed})
+An expression for the alignment of a structure field @var{field} if the
+alignment computed in the usual way is @var{computed}.  GCC uses
+this value instead of the value in @code{BIGGEST_ALIGNMENT} or
+@code{BIGGEST_FIELD_ALIGNMENT}, if defined.
+
+@findex MAX_OFILE_ALIGNMENT
+@item MAX_OFILE_ALIGNMENT
+Biggest alignment supported by the object file format of this machine.
+Use this macro to limit the alignment which can be specified using the
+@code{__attribute__ ((aligned (@var{n})))} construct.  If not defined,
+the default value is @code{BIGGEST_ALIGNMENT}.
+
+@findex DATA_ALIGNMENT
+@item DATA_ALIGNMENT (@var{type}, @var{basic-align})
+If defined, a C expression to compute the alignment for a variable in
+the static store.  @var{type} is the data type, and @var{basic-align} is
+the alignment that the object would ordinarily have.  The value of this
+macro is used instead of that alignment to align the object.
+
+If this macro is not defined, then @var{basic-align} is used.
+
+@findex strcpy
+One use of this macro is to increase alignment of medium-size data to
+make it all fit in fewer cache lines.  Another is to cause character
+arrays to be word-aligned so that @code{strcpy} calls that copy
+constants to character arrays can be done inline.
+
+@findex CONSTANT_ALIGNMENT
+@item CONSTANT_ALIGNMENT (@var{constant}, @var{basic-align})
+If defined, a C expression to compute the alignment given to a constant
+that is being placed in memory.  @var{constant} is the constant and
+@var{basic-align} is the alignment that the object would ordinarily
+have.  The value of this macro is used instead of that alignment to
+align the object.
+
+If this macro is not defined, then @var{basic-align} is used.
+
+The typical use of this macro is to increase alignment for string
+constants to be word aligned so that @code{strcpy} calls that copy
+constants can be done inline.
+
+@findex LOCAL_ALIGNMENT
+@item LOCAL_ALIGNMENT (@var{type}, @var{basic-align})
+If defined, a C expression to compute the alignment for a variable in
+the local store.  @var{type} is the data type, and @var{basic-align} is
+the alignment that the object would ordinarily have.  The value of this
+macro is used instead of that alignment to align the object.
+
+If this macro is not defined, then @var{basic-align} is used.
+
+One use of this macro is to increase alignment of medium-size data to
+make it all fit in fewer cache lines.
+
+@findex EMPTY_FIELD_BOUNDARY
+@item EMPTY_FIELD_BOUNDARY
+Alignment in bits to be given to a structure bit-field that follows an
+empty field such as @code{int : 0;}.
+
+Note that @code{PCC_BITFIELD_TYPE_MATTERS} also affects the alignment
+that results from an empty field.
+
+@findex STRUCTURE_SIZE_BOUNDARY
+@item STRUCTURE_SIZE_BOUNDARY
+Number of bits which any structure or union's size must be a multiple of.
+Each structure or union's size is rounded up to a multiple of this.
+
+If you do not define this macro, the default is the same as
+@code{BITS_PER_UNIT}.
+
+@findex STRICT_ALIGNMENT
+@item STRICT_ALIGNMENT
+Define this macro to be the value 1 if instructions will fail to work
+if given data not on the nominal alignment.  If instructions will merely
+go slower in that case, define this macro as 0.
+
+@findex PCC_BITFIELD_TYPE_MATTERS
+@item PCC_BITFIELD_TYPE_MATTERS
+Define this if you wish to imitate the way many other C compilers handle
+alignment of bit-fields and the structures that contain them.
+
+The behavior is that the type written for a bit-field (@code{int},
+@code{short}, or other integer type) imposes an alignment for the
+entire structure, as if the structure really did contain an ordinary
+field of that type.  In addition, the bit-field is placed within the
+structure so that it would fit within such a field, not crossing a
+boundary for it.
+
+Thus, on most machines, a bit-field whose type is written as @code{int}
+would not cross a four-byte boundary, and would force four-byte
+alignment for the whole structure.  (The alignment used may not be four
+bytes; it is controlled by the other alignment parameters.)
+
+If the macro is defined, its definition should be a C expression;
+a nonzero value for the expression enables this behavior.
+
+Note that if this macro is not defined, or its value is zero, some
+bit-fields may cross more than one alignment boundary.  The compiler can
+support such references if there are @samp{insv}, @samp{extv}, and
+@samp{extzv} insns that can directly reference memory.
+
+The other known way of making bit-fields work is to define
+@code{STRUCTURE_SIZE_BOUNDARY} as large as @code{BIGGEST_ALIGNMENT}.
+Then every structure can be accessed with fullwords.
+
+Unless the machine has bit-field instructions or you define
+@code{STRUCTURE_SIZE_BOUNDARY} that way, you must define
+@code{PCC_BITFIELD_TYPE_MATTERS} to have a nonzero value.
+
+If your aim is to make GCC use the same conventions for laying out
+bit-fields as are used by another compiler, here is how to investigate
+what the other compiler does.  Compile and run this program:
+
+@example
+struct foo1
+@{
+  char x;
+  char :0;
+  char y;
+@};
+
+struct foo2
+@{
+  char x;
+  int :0;
+  char y;
+@};
+
+main ()
+@{
+  printf ("Size of foo1 is %d\n",
+          sizeof (struct foo1));
+  printf ("Size of foo2 is %d\n",
+          sizeof (struct foo2));
+  exit (0);
+@}
+@end example
+
+If this prints 2 and 5, then the compiler's behavior is what you would
+get from @code{PCC_BITFIELD_TYPE_MATTERS}.
+
+@findex BITFIELD_NBYTES_LIMITED
+@item BITFIELD_NBYTES_LIMITED
+Like PCC_BITFIELD_TYPE_MATTERS except that its effect is limited to
+aligning a bit-field within the structure.
+
+@findex MEMBER_TYPE_FORCES_BLK
+@item MEMBER_TYPE_FORCES_BLK (@var{field})
+Return 1 if a structure or array containing @var{field} should be accessed using
+@code{BLKMODE}.
+
+Normally, this is not needed.  See the file @file{c4x.h} for an example
+of how to use this macro to prevent a structure having a floating point
+field from being accessed in an integer mode.
+
+@findex ROUND_TYPE_SIZE
+@item ROUND_TYPE_SIZE (@var{type}, @var{computed}, @var{specified})
+Define this macro as an expression for the overall size of a type
+(given by @var{type} as a tree node) when the size computed in the
+usual way is @var{computed} and the alignment is @var{specified}.
+
+The default is to round @var{computed} up to a multiple of @var{specified}.
+
+@findex ROUND_TYPE_SIZE_UNIT
+@item ROUND_TYPE_SIZE_UNIT (@var{type}, @var{computed}, @var{specified})
+Similar to @code{ROUND_TYPE_SIZE}, but sizes and alignments are
+specified in units (bytes).  If you define @code{ROUND_TYPE_SIZE},
+you must also define this macro and they must be defined consistently
+with each other.
+
+@findex ROUND_TYPE_ALIGN
+@item ROUND_TYPE_ALIGN (@var{type}, @var{computed}, @var{specified})
+Define this macro as an expression for the alignment of a type (given
+by @var{type} as a tree node) if the alignment computed in the usual
+way is @var{computed} and the alignment explicitly specified was
+@var{specified}.
+
+The default is to use @var{specified} if it is larger; otherwise, use
+the smaller of @var{computed} and @code{BIGGEST_ALIGNMENT}
+
+@findex MAX_FIXED_MODE_SIZE
+@item MAX_FIXED_MODE_SIZE
+An integer expression for the size in bits of the largest integer
+machine mode that should actually be used.  All integer machine modes of
+this size or smaller can be used for structures and unions with the
+appropriate sizes.  If this macro is undefined, @code{GET_MODE_BITSIZE
+(DImode)} is assumed.
+
+@findex VECTOR_MODE_SUPPORTED_P
+@item VECTOR_MODE_SUPPORTED_P(@var{mode})
+Define this macro to be nonzero if the port is prepared to handle insns
+involving vector mode @var{mode}.  At the very least, it must have move
+patterns for this mode.
+
+@findex STACK_SAVEAREA_MODE
+@item STACK_SAVEAREA_MODE (@var{save_level})
+If defined, an expression of type @code{enum machine_mode} that
+specifies the mode of the save area operand of a
+@code{save_stack_@var{level}} named pattern (@pxref{Standard Names}).
+@var{save_level} is one of @code{SAVE_BLOCK}, @code{SAVE_FUNCTION}, or
+@code{SAVE_NONLOCAL} and selects which of the three named patterns is
+having its mode specified.
+
+You need not define this macro if it always returns @code{Pmode}.  You
+would most commonly define this macro if the
+@code{save_stack_@var{level}} patterns need to support both a 32- and a
+64-bit mode.
+
+@findex STACK_SIZE_MODE
+@item STACK_SIZE_MODE
+If defined, an expression of type @code{enum machine_mode} that
+specifies the mode of the size increment operand of an
+@code{allocate_stack} named pattern (@pxref{Standard Names}).
+
+You need not define this macro if it always returns @code{word_mode}.
+You would most commonly define this macro if the @code{allocate_stack}
+pattern needs to support both a 32- and a 64-bit mode.
+
+@findex CHECK_FLOAT_VALUE
+@item CHECK_FLOAT_VALUE (@var{mode}, @var{value}, @var{overflow})
+A C statement to validate the value @var{value} (of type
+@code{double}) for mode @var{mode}.  This means that you check whether
+@var{value} fits within the possible range of values for mode
+@var{mode} on this target machine.  The mode @var{mode} is always
+a mode of class @code{MODE_FLOAT}.  @var{overflow} is nonzero if
+the value is already known to be out of range.
+
+If @var{value} is not valid or if @var{overflow} is nonzero, you should
+set @var{overflow} to 1 and then assign some valid value to @var{value}.
+Allowing an invalid value to go through the compiler can produce
+incorrect assembler code which may even cause Unix assemblers to crash.
+
+This macro need not be defined if there is no work for it to do.
+
+@findex TARGET_FLOAT_FORMAT
+@item TARGET_FLOAT_FORMAT
+A code distinguishing the floating point format of the target machine.
+There are five defined values:
+
+@table @code
+@findex IEEE_FLOAT_FORMAT
+@item IEEE_FLOAT_FORMAT
+This code indicates IEEE floating point.  It is the default; there is no
+need to define this macro when the format is IEEE@.
+
+@findex VAX_FLOAT_FORMAT
+@item VAX_FLOAT_FORMAT
+This code indicates the ``D float'' format used on the VAX@.
+
+@findex IBM_FLOAT_FORMAT
+@item IBM_FLOAT_FORMAT
+This code indicates the format used on the IBM System/370.
+
+@findex C4X_FLOAT_FORMAT
+@item C4X_FLOAT_FORMAT
+This code indicates the format used on the TMS320C3x/C4x.
+
+@findex UNKNOWN_FLOAT_FORMAT
+@item UNKNOWN_FLOAT_FORMAT
+This code indicates any other format.
+@end table
+
+The value of this macro is compared with @code{HOST_FLOAT_FORMAT}, which
+is defined by the @command{configure} script, to determine whether the
+target machine has the same format as the host machine.  If any other
+formats are actually in use on supported machines, new codes should be
+defined for them.
+
+The ordering of the component words of floating point values stored in
+memory is controlled by @code{FLOAT_WORDS_BIG_ENDIAN}.
+
+@end table
+
+@node Type Layout
+@section Layout of Source Language Data Types
+
+These macros define the sizes and other characteristics of the standard
+basic data types used in programs being compiled.  Unlike the macros in
+the previous section, these apply to specific features of C and related
+languages, rather than to fundamental aspects of storage layout.
+
+@table @code
+@findex INT_TYPE_SIZE
+@item INT_TYPE_SIZE
+A C expression for the size in bits of the type @code{int} on the
+target machine.  If you don't define this, the default is one word.
+
+@findex SHORT_TYPE_SIZE
+@item SHORT_TYPE_SIZE
+A C expression for the size in bits of the type @code{short} on the
+target machine.  If you don't define this, the default is half a word.
+(If this would be less than one storage unit, it is rounded up to one
+unit.)
+
+@findex LONG_TYPE_SIZE
+@item LONG_TYPE_SIZE
+A C expression for the size in bits of the type @code{long} on the
+target machine.  If you don't define this, the default is one word.
+
+@findex ADA_LONG_TYPE_SIZE
+@item ADA_LONG_TYPE_SIZE
+On some machines, the size used for the Ada equivalent of the type
+@code{long} by a native Ada compiler differs from that used by C.  In
+that situation, define this macro to be a C expression to be used for
+the size of that type.  If you don't define this, the default is the
+value of @code{LONG_TYPE_SIZE}.
+
+@findex MAX_LONG_TYPE_SIZE
+@item MAX_LONG_TYPE_SIZE
+Maximum number for the size in bits of the type @code{long} on the
+target machine.  If this is undefined, the default is
+@code{LONG_TYPE_SIZE}.  Otherwise, it is the constant value that is the
+largest value that @code{LONG_TYPE_SIZE} can have at run-time.  This is
+used in @code{cpp}.
+
+@findex LONG_LONG_TYPE_SIZE
+@item LONG_LONG_TYPE_SIZE
+A C expression for the size in bits of the type @code{long long} on the
+target machine.  If you don't define this, the default is two
+words.  If you want to support GNU Ada on your machine, the value of this
+macro must be at least 64.
+
+@findex CHAR_TYPE_SIZE
+@item CHAR_TYPE_SIZE
+A C expression for the size in bits of the type @code{char} on the
+target machine.  If you don't define this, the default is
+@code{BITS_PER_UNIT}.
+
+@findex MAX_CHAR_TYPE_SIZE
+@item MAX_CHAR_TYPE_SIZE
+Maximum number for the size in bits of the type @code{char} on the
+target machine.  If this is undefined, the default is
+@code{CHAR_TYPE_SIZE}.  Otherwise, it is the constant value that is the
+largest value that @code{CHAR_TYPE_SIZE} can have at run-time.  This is
+used in @code{cpp}.
+
+@findex BOOL_TYPE_SIZE
+@item BOOL_TYPE_SIZE
+A C expression for the size in bits of the C++ type @code{bool} on the
+target machine.  If you don't define this, the default is
+@code{CHAR_TYPE_SIZE}.
+
+@findex FLOAT_TYPE_SIZE
+@item FLOAT_TYPE_SIZE
+A C expression for the size in bits of the type @code{float} on the
+target machine.  If you don't define this, the default is one word.
+
+@findex DOUBLE_TYPE_SIZE
+@item DOUBLE_TYPE_SIZE
+A C expression for the size in bits of the type @code{double} on the
+target machine.  If you don't define this, the default is two
+words.
+
+@findex LONG_DOUBLE_TYPE_SIZE
+@item LONG_DOUBLE_TYPE_SIZE
+A C expression for the size in bits of the type @code{long double} on
+the target machine.  If you don't define this, the default is two
+words.
+
+@findex MAX_LONG_DOUBLE_TYPE_SIZE
+Maximum number for the size in bits of the type @code{long double} on the
+target machine.  If this is undefined, the default is
+@code{LONG_DOUBLE_TYPE_SIZE}.  Otherwise, it is the constant value that is
+the largest value that @code{LONG_DOUBLE_TYPE_SIZE} can have at run-time.
+This is used in @code{cpp}.
+
+@findex INTEL_EXTENDED_IEEE_FORMAT
+Define this macro to be 1 if the target machine uses 80-bit floating-point
+values with 128-bit size and alignment.  This is used in @file{real.c}.
+
+@findex WIDEST_HARDWARE_FP_SIZE
+@item WIDEST_HARDWARE_FP_SIZE
+A C expression for the size in bits of the widest floating-point format
+supported by the hardware.  If you define this macro, you must specify a
+value less than or equal to the value of @code{LONG_DOUBLE_TYPE_SIZE}.
+If you do not define this macro, the value of @code{LONG_DOUBLE_TYPE_SIZE}
+is the default.
+
+@findex DEFAULT_SIGNED_CHAR
+@item DEFAULT_SIGNED_CHAR
+An expression whose value is 1 or 0, according to whether the type
+@code{char} should be signed or unsigned by default.  The user can
+always override this default with the options @option{-fsigned-char}
+and @option{-funsigned-char}.
+
+@findex DEFAULT_SHORT_ENUMS
+@item DEFAULT_SHORT_ENUMS
+A C expression to determine whether to give an @code{enum} type
+only as many bytes as it takes to represent the range of possible values
+of that type.  A nonzero value means to do that; a zero value means all
+@code{enum} types should be allocated like @code{int}.
+
+If you don't define the macro, the default is 0.
+
+@findex SIZE_TYPE
+@item SIZE_TYPE
+A C expression for a string describing the name of the data type to use
+for size values.  The typedef name @code{size_t} is defined using the
+contents of the string.
+
+The string can contain more than one keyword.  If so, separate them with
+spaces, and write first any length keyword, then @code{unsigned} if
+appropriate, and finally @code{int}.  The string must exactly match one
+of the data type names defined in the function
+@code{init_decl_processing} in the file @file{c-decl.c}.  You may not
+omit @code{int} or change the order---that would cause the compiler to
+crash on startup.
+
+If you don't define this macro, the default is @code{"long unsigned
+int"}.
+
+@findex PTRDIFF_TYPE
+@item PTRDIFF_TYPE
+A C expression for a string describing the name of the data type to use
+for the result of subtracting two pointers.  The typedef name
+@code{ptrdiff_t} is defined using the contents of the string.  See
+@code{SIZE_TYPE} above for more information.
+
+If you don't define this macro, the default is @code{"long int"}.
+
+@findex WCHAR_TYPE
+@item WCHAR_TYPE
+A C expression for a string describing the name of the data type to use
+for wide characters.  The typedef name @code{wchar_t} is defined using
+the contents of the string.  See @code{SIZE_TYPE} above for more
+information.
+
+If you don't define this macro, the default is @code{"int"}.
+
+@findex WCHAR_TYPE_SIZE
+@item WCHAR_TYPE_SIZE
+A C expression for the size in bits of the data type for wide
+characters.  This is used in @code{cpp}, which cannot make use of
+@code{WCHAR_TYPE}.
+
+@findex MAX_WCHAR_TYPE_SIZE
+@item MAX_WCHAR_TYPE_SIZE
+Maximum number for the size in bits of the data type for wide
+characters.  If this is undefined, the default is
+@code{WCHAR_TYPE_SIZE}.  Otherwise, it is the constant value that is the
+largest value that @code{WCHAR_TYPE_SIZE} can have at run-time.  This is
+used in @code{cpp}.
+
+@findex GCOV_TYPE_SIZE
+@item GCOV_TYPE_SIZE
+A C expression for the size in bits of the type used for gcov counters on the
+target machine.  If you don't define this, the default is one
+@code{LONG_TYPE_SIZE} in case it is greater or equal to 64-bit and
+@code{LONG_LONG_TYPE_SIZE} otherwise.  You may want to re-define the type to
+ensure atomicity for counters in multithreaded programs.
+
+@findex WINT_TYPE
+@item WINT_TYPE
+A C expression for a string describing the name of the data type to
+use for wide characters passed to @code{printf} and returned from
+@code{getwc}.  The typedef name @code{wint_t} is defined using the
+contents of the string.  See @code{SIZE_TYPE} above for more
+information.
+
+If you don't define this macro, the default is @code{"unsigned int"}.
+
+@findex INTMAX_TYPE
+@item INTMAX_TYPE
+A C expression for a string describing the name of the data type that
+can represent any value of any standard or extended signed integer type.
+The typedef name @code{intmax_t} is defined using the contents of the
+string.  See @code{SIZE_TYPE} above for more information.
+
+If you don't define this macro, the default is the first of
+@code{"int"}, @code{"long int"}, or @code{"long long int"} that has as
+much precision as @code{long long int}.
+
+@findex UINTMAX_TYPE
+@item UINTMAX_TYPE
+A C expression for a string describing the name of the data type that
+can represent any value of any standard or extended unsigned integer
+type.  The typedef name @code{uintmax_t} is defined using the contents
+of the string.  See @code{SIZE_TYPE} above for more information.
+
+If you don't define this macro, the default is the first of
+@code{"unsigned int"}, @code{"long unsigned int"}, or @code{"long long
+unsigned int"} that has as much precision as @code{long long unsigned
+int}.
+
+@findex TARGET_PTRMEMFUNC_VBIT_LOCATION
+@item TARGET_PTRMEMFUNC_VBIT_LOCATION
+The C++ compiler represents a pointer-to-member-function with a struct
+that looks like:
+
+@example
+  struct @{
+    union @{
+      void (*fn)();
+      ptrdiff_t vtable_index;
+    @};
+    ptrdiff_t delta;
+  @};
+@end example
+
+@noindent
+The C++ compiler must use one bit to indicate whether the function that
+will be called through a pointer-to-member-function is virtual.
+Normally, we assume that the low-order bit of a function pointer must
+always be zero.  Then, by ensuring that the vtable_index is odd, we can
+distinguish which variant of the union is in use.  But, on some
+platforms function pointers can be odd, and so this doesn't work.  In
+that case, we use the low-order bit of the @code{delta} field, and shift
+the remainder of the @code{delta} field to the left.
+
+GCC will automatically make the right selection about where to store
+this bit using the @code{FUNCTION_BOUNDARY} setting for your platform.
+However, some platforms such as ARM/Thumb have @code{FUNCTION_BOUNDARY}
+set such that functions always start at even addresses, but the lowest
+bit of pointers to functions indicate whether the function at that
+address is in ARM or Thumb mode.  If this is the case of your
+architecture, you should define this macro to
+@code{ptrmemfunc_vbit_in_delta}.
+
+In general, you should not have to define this macro.  On architectures
+in which function addresses are always even, according to
+@code{FUNCTION_BOUNDARY}, GCC will automatically define this macro to
+@code{ptrmemfunc_vbit_in_pfn}.
+
+@findex TARGET_VTABLE_USES_DESCRIPTORS
+@item TARGET_VTABLE_USES_DESCRIPTORS
+Normally, the C++ compiler uses function pointers in vtables.  This
+macro allows the target to change to use ``function descriptors'' 
+instead.  Function descriptors are found on targets for whom a
+function pointer is actually a small data structure.  Normally the
+data structure consists of the actual code address plus a data 
+pointer to which the function's data is relative.
+
+If vtables are used, the value of this macro should be the number
+of words that the function descriptor occupies.
+@end table
+
+@node Escape Sequences
+@section Target Character Escape Sequences
+@cindex escape sequences
+
+By default, GCC assumes that the C character escape sequences take on
+their ASCII values for the target.  If this is not correct, you must
+explicitly define all of the macros below.
+
+@table @code
+@findex TARGET_BELL
+@item TARGET_BELL
+A C constant expression for the integer value for escape sequence
+@samp{\a}.
+
+@findex TARGET_ESC
+@item TARGET_ESC
+A C constant expression for the integer value of the target escape
+character.  As an extension, GCC evaluates the escape sequences
+@samp{\e} and @samp{\E} to this.
+
+@findex TARGET_TAB
+@findex TARGET_BS
+@findex TARGET_NEWLINE
+@item TARGET_BS
+@itemx TARGET_TAB
+@itemx TARGET_NEWLINE
+C constant expressions for the integer values for escape sequences
+@samp{\b}, @samp{\t} and @samp{\n}.
+
+@findex TARGET_VT
+@findex TARGET_FF
+@findex TARGET_CR
+@item TARGET_VT
+@itemx TARGET_FF
+@itemx TARGET_CR
+C constant expressions for the integer values for escape sequences
+@samp{\v}, @samp{\f} and @samp{\r}.
+@end table
+
+@node Registers
+@section Register Usage
+@cindex register usage
+
+This section explains how to describe what registers the target machine
+has, and how (in general) they can be used.
+
+The description of which registers a specific instruction can use is
+done with register classes; see @ref{Register Classes}.  For information
+on using registers to access a stack frame, see @ref{Frame Registers}.
+For passing values in registers, see @ref{Register Arguments}.
+For returning values in registers, see @ref{Scalar Return}.
+
+@menu
+* Register Basics::		Number and kinds of registers.
+* Allocation Order::		Order in which registers are allocated.
+* Values in Registers::		What kinds of values each reg can hold.
+* Leaf Functions::		Renumbering registers for leaf functions.
+* Stack Registers::		Handling a register stack such as 80387.
+@end menu
+
+@node Register Basics
+@subsection Basic Characteristics of Registers
+
+@c prevent bad page break with this line
+Registers have various characteristics.
+
+@table @code
+@findex FIRST_PSEUDO_REGISTER
+@item FIRST_PSEUDO_REGISTER
+Number of hardware registers known to the compiler.  They receive
+numbers 0 through @code{FIRST_PSEUDO_REGISTER-1}; thus, the first
+pseudo register's number really is assigned the number
+@code{FIRST_PSEUDO_REGISTER}.
+
+@item FIXED_REGISTERS
+@findex FIXED_REGISTERS
+@cindex fixed register
+An initializer that says which registers are used for fixed purposes
+all throughout the compiled code and are therefore not available for
+general allocation.  These would include the stack pointer, the frame
+pointer (except on machines where that can be used as a general
+register when no frame pointer is needed), the program counter on
+machines where that is considered one of the addressable registers,
+and any other numbered register with a standard use.
+
+This information is expressed as a sequence of numbers, separated by
+commas and surrounded by braces.  The @var{n}th number is 1 if
+register @var{n} is fixed, 0 otherwise.
+
+The table initialized from this macro, and the table initialized by
+the following one, may be overridden at run time either automatically,
+by the actions of the macro @code{CONDITIONAL_REGISTER_USAGE}, or by
+the user with the command options @option{-ffixed-@var{reg}},
+@option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}.
+
+@findex CALL_USED_REGISTERS
+@item CALL_USED_REGISTERS
+@cindex call-used register
+@cindex call-clobbered register
+@cindex call-saved register
+Like @code{FIXED_REGISTERS} but has 1 for each register that is
+clobbered (in general) by function calls as well as for fixed
+registers.  This macro therefore identifies the registers that are not
+available for general allocation of values that must live across
+function calls.
+
+If a register has 0 in @code{CALL_USED_REGISTERS}, the compiler
+automatically saves it on function entry and restores it on function
+exit, if the register is used within the function.
+
+@findex CALL_REALLY_USED_REGISTERS
+@item CALL_REALLY_USED_REGISTERS
+@cindex call-used register
+@cindex call-clobbered register
+@cindex call-saved register
+Like @code{CALL_USED_REGISTERS} except this macro doesn't require 
+that the entire set of @code{FIXED_REGISTERS} be included.  
+(@code{CALL_USED_REGISTERS} must be a superset of @code{FIXED_REGISTERS}).
+This macro is optional.  If not specified, it defaults to the value 
+of @code{CALL_USED_REGISTERS}.
+
+@findex HARD_REGNO_CALL_PART_CLOBBERED
+@item HARD_REGNO_CALL_PART_CLOBBERED (@var{regno}, @var{mode})
+@cindex call-used register
+@cindex call-clobbered register
+@cindex call-saved register
+A C expression that is nonzero if it is not permissible to store a
+value of mode @var{mode} in hard register number @var{regno} across a
+call without some part of it being clobbered.  For most machines this
+macro need not be defined.  It is only required for machines that do not
+preserve the entire contents of a register across a call.
+
+@findex CONDITIONAL_REGISTER_USAGE
+@findex fixed_regs
+@findex call_used_regs
+@item CONDITIONAL_REGISTER_USAGE
+Zero or more C statements that may conditionally modify five variables
+@code{fixed_regs}, @code{call_used_regs}, @code{global_regs},
+@code{reg_names}, and @code{reg_class_contents}, to take into account
+any dependence of these register sets on target flags.  The first three
+of these are of type @code{char []} (interpreted as Boolean vectors).
+@code{global_regs} is a @code{const char *[]}, and
+@code{reg_class_contents} is a @code{HARD_REG_SET}.  Before the macro is
+called, @code{fixed_regs}, @code{call_used_regs},
+@code{reg_class_contents}, and @code{reg_names} have been initialized
+from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},
+@code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.
+@code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},
+@option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}
+command options have been applied.
+
+You need not define this macro if it has no work to do.
+
+@cindex disabling certain registers
+@cindex controlling register usage
+If the usage of an entire class of registers depends on the target
+flags, you may indicate this to GCC by using this macro to modify
+@code{fixed_regs} and @code{call_used_regs} to 1 for each of the
+registers in the classes which should not be used by GCC@.  Also define
+the macro @code{REG_CLASS_FROM_LETTER} to return @code{NO_REGS} if it
+is called with a letter for a class that shouldn't be used.
+
+(However, if this class is not included in @code{GENERAL_REGS} and all
+of the insn patterns whose constraints permit this class are
+controlled by target switches, then GCC will automatically avoid using
+these registers when the target switches are opposed to them.)
+
+@findex NON_SAVING_SETJMP
+@item NON_SAVING_SETJMP
+If this macro is defined and has a nonzero value, it means that
+@code{setjmp} and related functions fail to save the registers, or that
+@code{longjmp} fails to restore them.  To compensate, the compiler
+avoids putting variables in registers in functions that use
+@code{setjmp}.
+
+@findex INCOMING_REGNO
+@item INCOMING_REGNO (@var{out})
+Define this macro if the target machine has register windows.  This C
+expression returns the register number as seen by the called function
+corresponding to the register number @var{out} as seen by the calling
+function.  Return @var{out} if register number @var{out} is not an
+outbound register.
+
+@findex OUTGOING_REGNO
+@item OUTGOING_REGNO (@var{in})
+Define this macro if the target machine has register windows.  This C
+expression returns the register number as seen by the calling function
+corresponding to the register number @var{in} as seen by the called
+function.  Return @var{in} if register number @var{in} is not an inbound
+register.
+
+@findex LOCAL_REGNO
+@item LOCAL_REGNO (@var{regno})
+Define this macro if the target machine has register windows.  This C
+expression returns true if the register is call-saved but is in the
+register window.  Unlike most call-saved registers, such registers
+need not be explicitly restored on function exit or during non-local
+gotos.
+
+@ignore
+@findex PC_REGNUM
+@item PC_REGNUM
+If the program counter has a register number, define this as that
+register number.  Otherwise, do not define it.
+@end ignore
+@end table
+
+@node Allocation Order
+@subsection Order of Allocation of Registers
+@cindex order of register allocation
+@cindex register allocation order
+
+@c prevent bad page break with this line
+Registers are allocated in order.
+
+@table @code
+@findex REG_ALLOC_ORDER
+@item REG_ALLOC_ORDER
+If defined, an initializer for a vector of integers, containing the
+numbers of hard registers in the order in which GCC should prefer
+to use them (from most preferred to least).
+
+If this macro is not defined, registers are used lowest numbered first
+(all else being equal).
+
+One use of this macro is on machines where the highest numbered
+registers must always be saved and the save-multiple-registers
+instruction supports only sequences of consecutive registers.  On such
+machines, define @code{REG_ALLOC_ORDER} to be an initializer that lists
+the highest numbered allocable register first.
+
+@findex ORDER_REGS_FOR_LOCAL_ALLOC
+@item ORDER_REGS_FOR_LOCAL_ALLOC
+A C statement (sans semicolon) to choose the order in which to allocate
+hard registers for pseudo-registers local to a basic block.
+
+Store the desired register order in the array @code{reg_alloc_order}.
+Element 0 should be the register to allocate first; element 1, the next
+register; and so on.
+
+The macro body should not assume anything about the contents of
+@code{reg_alloc_order} before execution of the macro.
+
+On most machines, it is not necessary to define this macro.
+@end table
+
+@node Values in Registers
+@subsection How Values Fit in Registers
+
+This section discusses the macros that describe which kinds of values
+(specifically, which machine modes) each register can hold, and how many
+consecutive registers are needed for a given mode.
+
+@table @code
+@findex HARD_REGNO_NREGS
+@item HARD_REGNO_NREGS (@var{regno}, @var{mode})
+A C expression for the number of consecutive hard registers, starting
+at register number @var{regno}, required to hold a value of mode
+@var{mode}.
+
+On a machine where all registers are exactly one word, a suitable
+definition of this macro is
+
+@smallexample
+#define HARD_REGNO_NREGS(REGNO, MODE)            \
+   ((GET_MODE_SIZE (MODE) + UNITS_PER_WORD - 1)  \
+    / UNITS_PER_WORD)
+@end smallexample
+
+@findex HARD_REGNO_MODE_OK
+@item HARD_REGNO_MODE_OK (@var{regno}, @var{mode})
+A C expression that is nonzero if it is permissible to store a value
+of mode @var{mode} in hard register number @var{regno} (or in several
+registers starting with that one).  For a machine where all registers
+are equivalent, a suitable definition is
+
+@smallexample
+#define HARD_REGNO_MODE_OK(REGNO, MODE) 1
+@end smallexample
+
+You need not include code to check for the numbers of fixed registers,
+because the allocation mechanism considers them to be always occupied.
+
+@cindex register pairs
+On some machines, double-precision values must be kept in even/odd
+register pairs.  You can implement that by defining this macro to reject
+odd register numbers for such modes.
+
+The minimum requirement for a mode to be OK in a register is that the
+@samp{mov@var{mode}} instruction pattern support moves between the
+register and other hard register in the same class and that moving a
+value into the register and back out not alter it.
+
+Since the same instruction used to move @code{word_mode} will work for
+all narrower integer modes, it is not necessary on any machine for
+@code{HARD_REGNO_MODE_OK} to distinguish between these modes, provided
+you define patterns @samp{movhi}, etc., to take advantage of this.  This
+is useful because of the interaction between @code{HARD_REGNO_MODE_OK}
+and @code{MODES_TIEABLE_P}; it is very desirable for all integer modes
+to be tieable.
+
+Many machines have special registers for floating point arithmetic.
+Often people assume that floating point machine modes are allowed only
+in floating point registers.  This is not true.  Any registers that
+can hold integers can safely @emph{hold} a floating point machine
+mode, whether or not floating arithmetic can be done on it in those
+registers.  Integer move instructions can be used to move the values.
+
+On some machines, though, the converse is true: fixed-point machine
+modes may not go in floating registers.  This is true if the floating
+registers normalize any value stored in them, because storing a
+non-floating value there would garble it.  In this case,
+@code{HARD_REGNO_MODE_OK} should reject fixed-point machine modes in
+floating registers.  But if the floating registers do not automatically
+normalize, if you can store any bit pattern in one and retrieve it
+unchanged without a trap, then any machine mode may go in a floating
+register, so you can define this macro to say so.
+
+The primary significance of special floating registers is rather that
+they are the registers acceptable in floating point arithmetic
+instructions.  However, this is of no concern to
+@code{HARD_REGNO_MODE_OK}.  You handle it by writing the proper
+constraints for those instructions.
+
+On some machines, the floating registers are especially slow to access,
+so that it is better to store a value in a stack frame than in such a
+register if floating point arithmetic is not being done.  As long as the
+floating registers are not in class @code{GENERAL_REGS}, they will not
+be used unless some pattern's constraint asks for one.
+
+@findex MODES_TIEABLE_P
+@item MODES_TIEABLE_P (@var{mode1}, @var{mode2})
+A C expression that is nonzero if a value of mode
+@var{mode1} is accessible in mode @var{mode2} without copying.
+
+If @code{HARD_REGNO_MODE_OK (@var{r}, @var{mode1})} and
+@code{HARD_REGNO_MODE_OK (@var{r}, @var{mode2})} are always the same for
+any @var{r}, then @code{MODES_TIEABLE_P (@var{mode1}, @var{mode2})}
+should be nonzero.  If they differ for any @var{r}, you should define
+this macro to return zero unless some other mechanism ensures the
+accessibility of the value in a narrower mode.
+
+You should define this macro to return nonzero in as many cases as
+possible since doing so will allow GCC to perform better register
+allocation.
+
+@findex AVOID_CCMODE_COPIES
+@item AVOID_CCMODE_COPIES
+Define this macro if the compiler should avoid copies to/from @code{CCmode}
+registers.  You should only define this macro if support for copying to/from
+@code{CCmode} is incomplete.
+@end table
+
+@node Leaf Functions
+@subsection Handling Leaf Functions
+
+@cindex leaf functions
+@cindex functions, leaf
+On some machines, a leaf function (i.e., one which makes no calls) can run
+more efficiently if it does not make its own register window.  Often this
+means it is required to receive its arguments in the registers where they
+are passed by the caller, instead of the registers where they would
+normally arrive.
+
+The special treatment for leaf functions generally applies only when
+other conditions are met; for example, often they may use only those
+registers for its own variables and temporaries.  We use the term ``leaf
+function'' to mean a function that is suitable for this special
+handling, so that functions with no calls are not necessarily ``leaf
+functions''.
+
+GCC assigns register numbers before it knows whether the function is
+suitable for leaf function treatment.  So it needs to renumber the
+registers in order to output a leaf function.  The following macros
+accomplish this.
+
+@table @code
+@findex LEAF_REGISTERS
+@item LEAF_REGISTERS
+Name of a char vector, indexed by hard register number, which
+contains 1 for a register that is allowable in a candidate for leaf
+function treatment.
+
+If leaf function treatment involves renumbering the registers, then the
+registers marked here should be the ones before renumbering---those that
+GCC would ordinarily allocate.  The registers which will actually be
+used in the assembler code, after renumbering, should not be marked with 1
+in this vector.
+
+Define this macro only if the target machine offers a way to optimize
+the treatment of leaf functions.
+
+@findex LEAF_REG_REMAP
+@item LEAF_REG_REMAP (@var{regno})
+A C expression whose value is the register number to which @var{regno}
+should be renumbered, when a function is treated as a leaf function.
+
+If @var{regno} is a register number which should not appear in a leaf
+function before renumbering, then the expression should yield @minus{}1, which
+will cause the compiler to abort.
+
+Define this macro only if the target machine offers a way to optimize the
+treatment of leaf functions, and registers need to be renumbered to do
+this.
+@end table
+
+@findex current_function_is_leaf
+@findex current_function_uses_only_leaf_regs
+@code{TARGET_ASM_FUNCTION_PROLOGUE} and
+@code{TARGET_ASM_FUNCTION_EPILOGUE} must usually treat leaf functions
+specially.  They can test the C variable @code{current_function_is_leaf}
+which is nonzero for leaf functions.  @code{current_function_is_leaf} is
+set prior to local register allocation and is valid for the remaining
+compiler passes.  They can also test the C variable
+@code{current_function_uses_only_leaf_regs} which is nonzero for leaf
+functions which only use leaf registers.
+@code{current_function_uses_only_leaf_regs} is valid after reload and is
+only useful if @code{LEAF_REGISTERS} is defined.
+@c changed this to fix overfull.  ALSO:  why the "it" at the beginning
+@c of the next paragraph?!  --mew 2feb93
+
+@node Stack Registers
+@subsection Registers That Form a Stack
+
+There are special features to handle computers where some of the
+``registers'' form a stack, as in the 80387 coprocessor for the 80386.
+Stack registers are normally written by pushing onto the stack, and are
+numbered relative to the top of the stack.
+
+Currently, GCC can only handle one group of stack-like registers, and
+they must be consecutively numbered.
+
+@table @code
+@findex STACK_REGS
+@item STACK_REGS
+Define this if the machine has any stack-like registers.
+
+@findex FIRST_STACK_REG
+@item FIRST_STACK_REG
+The number of the first stack-like register.  This one is the top
+of the stack.
+
+@findex LAST_STACK_REG
+@item LAST_STACK_REG
+The number of the last stack-like register.  This one is the bottom of
+the stack.
+@end table
+
+@node Register Classes
+@section Register Classes
+@cindex register class definitions
+@cindex class definitions, register
+
+On many machines, the numbered registers are not all equivalent.
+For example, certain registers may not be allowed for indexed addressing;
+certain registers may not be allowed in some instructions.  These machine
+restrictions are described to the compiler using @dfn{register classes}.
+
+You define a number of register classes, giving each one a name and saying
+which of the registers belong to it.  Then you can specify register classes
+that are allowed as operands to particular instruction patterns.
+
+@findex ALL_REGS
+@findex NO_REGS
+In general, each register will belong to several classes.  In fact, one
+class must be named @code{ALL_REGS} and contain all the registers.  Another
+class must be named @code{NO_REGS} and contain no registers.  Often the
+union of two classes will be another class; however, this is not required.
+
+@findex GENERAL_REGS
+One of the classes must be named @code{GENERAL_REGS}.  There is nothing
+terribly special about the name, but the operand constraint letters
+@samp{r} and @samp{g} specify this class.  If @code{GENERAL_REGS} is
+the same as @code{ALL_REGS}, just define it as a macro which expands
+to @code{ALL_REGS}.
+
+Order the classes so that if class @var{x} is contained in class @var{y}
+then @var{x} has a lower class number than @var{y}.
+
+The way classes other than @code{GENERAL_REGS} are specified in operand
+constraints is through machine-dependent operand constraint letters.
+You can define such letters to correspond to various classes, then use
+them in operand constraints.
+
+You should define a class for the union of two classes whenever some
+instruction allows both classes.  For example, if an instruction allows
+either a floating point (coprocessor) register or a general register for a
+certain operand, you should define a class @code{FLOAT_OR_GENERAL_REGS}
+which includes both of them.  Otherwise you will get suboptimal code.
+
+You must also specify certain redundant information about the register
+classes: for each class, which classes contain it and which ones are
+contained in it; for each pair of classes, the largest class contained
+in their union.
+
+When a value occupying several consecutive registers is expected in a
+certain class, all the registers used must belong to that class.
+Therefore, register classes cannot be used to enforce a requirement for
+a register pair to start with an even-numbered register.  The way to
+specify this requirement is with @code{HARD_REGNO_MODE_OK}.
+
+Register classes used for input-operands of bitwise-and or shift
+instructions have a special requirement: each such class must have, for
+each fixed-point machine mode, a subclass whose registers can transfer that
+mode to or from memory.  For example, on some machines, the operations for
+single-byte values (@code{QImode}) are limited to certain registers.  When
+this is so, each register class that is used in a bitwise-and or shift
+instruction must have a subclass consisting of registers from which
+single-byte values can be loaded or stored.  This is so that
+@code{PREFERRED_RELOAD_CLASS} can always have a possible value to return.
+
+@table @code
+@findex enum reg_class
+@item enum reg_class
+An enumeral type that must be defined with all the register class names
+as enumeral values.  @code{NO_REGS} must be first.  @code{ALL_REGS}
+must be the last register class, followed by one more enumeral value,
+@code{LIM_REG_CLASSES}, which is not a register class but rather
+tells how many classes there are.
+
+Each register class has a number, which is the value of casting
+the class name to type @code{int}.  The number serves as an index
+in many of the tables described below.
+
+@findex N_REG_CLASSES
+@item N_REG_CLASSES
+The number of distinct register classes, defined as follows:
+
+@example
+#define N_REG_CLASSES (int) LIM_REG_CLASSES
+@end example
+
+@findex REG_CLASS_NAMES
+@item REG_CLASS_NAMES
+An initializer containing the names of the register classes as C string
+constants.  These names are used in writing some of the debugging dumps.
+
+@findex REG_CLASS_CONTENTS
+@item REG_CLASS_CONTENTS
+An initializer containing the contents of the register classes, as integers
+which are bit masks.  The @var{n}th integer specifies the contents of class
+@var{n}.  The way the integer @var{mask} is interpreted is that
+register @var{r} is in the class if @code{@var{mask} & (1 << @var{r})} is 1.
+
+When the machine has more than 32 registers, an integer does not suffice.
+Then the integers are replaced by sub-initializers, braced groupings containing
+several integers.  Each sub-initializer must be suitable as an initializer
+for the type @code{HARD_REG_SET} which is defined in @file{hard-reg-set.h}.
+In this situation, the first integer in each sub-initializer corresponds to
+registers 0 through 31, the second integer to registers 32 through 63, and
+so on.
+
+@findex REGNO_REG_CLASS
+@item REGNO_REG_CLASS (@var{regno})
+A C expression whose value is a register class containing hard register
+@var{regno}.  In general there is more than one such class; choose a class
+which is @dfn{minimal}, meaning that no smaller class also contains the
+register.
+
+@findex BASE_REG_CLASS
+@item BASE_REG_CLASS
+A macro whose definition is the name of the class to which a valid
+base register must belong.  A base register is one used in an address
+which is the register value plus a displacement.
+
+@findex MODE_BASE_REG_CLASS
+@item MODE_BASE_REG_CLASS (@var{mode})
+This is a variation of the @code{BASE_REG_CLASS} macro which allows
+the selection of a base register in a mode depenedent manner.  If
+@var{mode} is VOIDmode then it should return the same value as
+@code{BASE_REG_CLASS}.
+
+@findex INDEX_REG_CLASS
+@item INDEX_REG_CLASS
+A macro whose definition is the name of the class to which a valid
+index register must belong.  An index register is one used in an
+address where its value is either multiplied by a scale factor or
+added to another register (as well as added to a displacement).
+
+@findex REG_CLASS_FROM_LETTER
+@item REG_CLASS_FROM_LETTER (@var{char})
+A C expression which defines the machine-dependent operand constraint
+letters for register classes.  If @var{char} is such a letter, the
+value should be the register class corresponding to it.  Otherwise,
+the value should be @code{NO_REGS}.  The register letter @samp{r},
+corresponding to class @code{GENERAL_REGS}, will not be passed
+to this macro; you do not need to handle it.
+
+@findex REGNO_OK_FOR_BASE_P
+@item REGNO_OK_FOR_BASE_P (@var{num})
+A C expression which is nonzero if register number @var{num} is
+suitable for use as a base register in operand addresses.  It may be
+either a suitable hard register or a pseudo register that has been
+allocated such a hard register.
+
+@findex REGNO_MODE_OK_FOR_BASE_P
+@item REGNO_MODE_OK_FOR_BASE_P (@var{num}, @var{mode})
+A C expression that is just like @code{REGNO_OK_FOR_BASE_P}, except that
+that expression may examine the mode of the memory reference in
+@var{mode}.  You should define this macro if the mode of the memory
+reference affects whether a register may be used as a base register.  If
+you define this macro, the compiler will use it instead of
+@code{REGNO_OK_FOR_BASE_P}.
+
+@findex REGNO_OK_FOR_INDEX_P
+@item REGNO_OK_FOR_INDEX_P (@var{num})
+A C expression which is nonzero if register number @var{num} is
+suitable for use as an index register in operand addresses.  It may be
+either a suitable hard register or a pseudo register that has been
+allocated such a hard register.
+
+The difference between an index register and a base register is that
+the index register may be scaled.  If an address involves the sum of
+two registers, neither one of them scaled, then either one may be
+labeled the ``base'' and the other the ``index''; but whichever
+labeling is used must fit the machine's constraints of which registers
+may serve in each capacity.  The compiler will try both labelings,
+looking for one that is valid, and will reload one or both registers
+only if neither labeling works.
+
+@findex PREFERRED_RELOAD_CLASS
+@item PREFERRED_RELOAD_CLASS (@var{x}, @var{class})
+A C expression that places additional restrictions on the register class
+to use when it is necessary to copy value @var{x} into a register in class
+@var{class}.  The value is a register class; perhaps @var{class}, or perhaps
+another, smaller class.  On many machines, the following definition is
+safe:
+
+@example
+#define PREFERRED_RELOAD_CLASS(X,CLASS) CLASS
+@end example
+
+Sometimes returning a more restrictive class makes better code.  For
+example, on the 68000, when @var{x} is an integer constant that is in range
+for a @samp{moveq} instruction, the value of this macro is always
+@code{DATA_REGS} as long as @var{class} includes the data registers.
+Requiring a data register guarantees that a @samp{moveq} will be used.
+
+If @var{x} is a @code{const_double}, by returning @code{NO_REGS}
+you can force @var{x} into a memory constant.  This is useful on
+certain machines where immediate floating values cannot be loaded into
+certain kinds of registers.
+
+@findex PREFERRED_OUTPUT_RELOAD_CLASS
+@item PREFERRED_OUTPUT_RELOAD_CLASS (@var{x}, @var{class})
+Like @code{PREFERRED_RELOAD_CLASS}, but for output reloads instead of
+input reloads.  If you don't define this macro, the default is to use
+@var{class}, unchanged.
+
+@findex LIMIT_RELOAD_CLASS
+@item LIMIT_RELOAD_CLASS (@var{mode}, @var{class})
+A C expression that places additional restrictions on the register class
+to use when it is necessary to be able to hold a value of mode
+@var{mode} in a reload register for which class @var{class} would
+ordinarily be used.
+
+Unlike @code{PREFERRED_RELOAD_CLASS}, this macro should be used when
+there are certain modes that simply can't go in certain reload classes.
+
+The value is a register class; perhaps @var{class}, or perhaps another,
+smaller class.
+
+Don't define this macro unless the target machine has limitations which
+require the macro to do something nontrivial.
+
+@findex SECONDARY_RELOAD_CLASS
+@findex SECONDARY_INPUT_RELOAD_CLASS
+@findex SECONDARY_OUTPUT_RELOAD_CLASS
+@item SECONDARY_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
+@itemx SECONDARY_INPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
+@itemx SECONDARY_OUTPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
+Many machines have some registers that cannot be copied directly to or
+from memory or even from other types of registers.  An example is the
+@samp{MQ} register, which on most machines, can only be copied to or
+from general registers, but not memory.  Some machines allow copying all
+registers to and from memory, but require a scratch register for stores
+to some memory locations (e.g., those with symbolic address on the RT,
+and those with certain symbolic address on the Sparc when compiling
+PIC)@.  In some cases, both an intermediate and a scratch register are
+required.
+
+You should define these macros to indicate to the reload phase that it may
+need to allocate at least one register for a reload in addition to the
+register to contain the data.  Specifically, if copying @var{x} to a
+register @var{class} in @var{mode} requires an intermediate register,
+you should define @code{SECONDARY_INPUT_RELOAD_CLASS} to return the
+largest register class all of whose registers can be used as
+intermediate registers or scratch registers.
+
+If copying a register @var{class} in @var{mode} to @var{x} requires an
+intermediate or scratch register, @code{SECONDARY_OUTPUT_RELOAD_CLASS}
+should be defined to return the largest register class required.  If the
+requirements for input and output reloads are the same, the macro
+@code{SECONDARY_RELOAD_CLASS} should be used instead of defining both
+macros identically.
+
+The values returned by these macros are often @code{GENERAL_REGS}.
+Return @code{NO_REGS} if no spare register is needed; i.e., if @var{x}
+can be directly copied to or from a register of @var{class} in
+@var{mode} without requiring a scratch register.  Do not define this
+macro if it would always return @code{NO_REGS}.
+
+If a scratch register is required (either with or without an
+intermediate register), you should define patterns for
+@samp{reload_in@var{m}} or @samp{reload_out@var{m}}, as required
+(@pxref{Standard Names}.  These patterns, which will normally be
+implemented with a @code{define_expand}, should be similar to the
+@samp{mov@var{m}} patterns, except that operand 2 is the scratch
+register.
+
+Define constraints for the reload register and scratch register that
+contain a single register class.  If the original reload register (whose
+class is @var{class}) can meet the constraint given in the pattern, the
+value returned by these macros is used for the class of the scratch
+register.  Otherwise, two additional reload registers are required.
+Their classes are obtained from the constraints in the insn pattern.
+
+@var{x} might be a pseudo-register or a @code{subreg} of a
+pseudo-register, which could either be in a hard register or in memory.
+Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is
+in memory and the hard register number if it is in a register.
+
+These macros should not be used in the case where a particular class of
+registers can only be copied to memory and not to another class of
+registers.  In that case, secondary reload registers are not needed and
+would not be helpful.  Instead, a stack location must be used to perform
+the copy and the @code{mov@var{m}} pattern should use memory as an
+intermediate storage.  This case often occurs between floating-point and
+general registers.
+
+@findex SECONDARY_MEMORY_NEEDED
+@item SECONDARY_MEMORY_NEEDED (@var{class1}, @var{class2}, @var{m})
+Certain machines have the property that some registers cannot be copied
+to some other registers without using memory.  Define this macro on
+those machines to be a C expression that is nonzero if objects of mode
+@var{m} in registers of @var{class1} can only be copied to registers of
+class @var{class2} by storing a register of @var{class1} into memory
+and loading that memory location into a register of @var{class2}.
+
+Do not define this macro if its value would always be zero.
+
+@findex SECONDARY_MEMORY_NEEDED_RTX
+@item SECONDARY_MEMORY_NEEDED_RTX (@var{mode})
+Normally when @code{SECONDARY_MEMORY_NEEDED} is defined, the compiler
+allocates a stack slot for a memory location needed for register copies.
+If this macro is defined, the compiler instead uses the memory location
+defined by this macro.
+
+Do not define this macro if you do not define
+@code{SECONDARY_MEMORY_NEEDED}.
+
+@findex SECONDARY_MEMORY_NEEDED_MODE
+@item SECONDARY_MEMORY_NEEDED_MODE (@var{mode})
+When the compiler needs a secondary memory location to copy between two
+registers of mode @var{mode}, it normally allocates sufficient memory to
+hold a quantity of @code{BITS_PER_WORD} bits and performs the store and
+load operations in a mode that many bits wide and whose class is the
+same as that of @var{mode}.
+
+This is right thing to do on most machines because it ensures that all
+bits of the register are copied and prevents accesses to the registers
+in a narrower mode, which some machines prohibit for floating-point
+registers.
+
+However, this default behavior is not correct on some machines, such as
+the DEC Alpha, that store short integers in floating-point registers
+differently than in integer registers.  On those machines, the default
+widening will not work correctly and you must define this macro to
+suppress that widening in some cases.  See the file @file{alpha.h} for
+details.
+
+Do not define this macro if you do not define
+@code{SECONDARY_MEMORY_NEEDED} or if widening @var{mode} to a mode that
+is @code{BITS_PER_WORD} bits wide is correct for your machine.
+
+@findex SMALL_REGISTER_CLASSES
+@item SMALL_REGISTER_CLASSES
+On some machines, it is risky to let hard registers live across arbitrary
+insns.  Typically, these machines have instructions that require values
+to be in specific registers (like an accumulator), and reload will fail
+if the required hard register is used for another purpose across such an
+insn.
+
+Define @code{SMALL_REGISTER_CLASSES} to be an expression with a nonzero
+value on these machines.  When this macro has a nonzero value, the
+compiler will try to minimize the lifetime of hard registers.
+
+It is always safe to define this macro with a nonzero value, but if you
+unnecessarily define it, you will reduce the amount of optimizations
+that can be performed in some cases.  If you do not define this macro
+with a nonzero value when it is required, the compiler will run out of
+spill registers and print a fatal error message.  For most machines, you
+should not define this macro at all.
+
+@findex CLASS_LIKELY_SPILLED_P
+@item CLASS_LIKELY_SPILLED_P (@var{class})
+A C expression whose value is nonzero if pseudos that have been assigned
+to registers of class @var{class} would likely be spilled because
+registers of @var{class} are needed for spill registers.
+
+The default value of this macro returns 1 if @var{class} has exactly one
+register and zero otherwise.  On most machines, this default should be
+used.  Only define this macro to some other expression if pseudos
+allocated by @file{local-alloc.c} end up in memory because their hard
+registers were needed for spill registers.  If this macro returns nonzero
+for those classes, those pseudos will only be allocated by
+@file{global.c}, which knows how to reallocate the pseudo to another
+register.  If there would not be another register available for
+reallocation, you should not change the definition of this macro since
+the only effect of such a definition would be to slow down register
+allocation.
+
+@findex CLASS_MAX_NREGS
+@item CLASS_MAX_NREGS (@var{class}, @var{mode})
+A C expression for the maximum number of consecutive registers
+of class @var{class} needed to hold a value of mode @var{mode}.
+
+This is closely related to the macro @code{HARD_REGNO_NREGS}.  In fact,
+the value of the macro @code{CLASS_MAX_NREGS (@var{class}, @var{mode})}
+should be the maximum value of @code{HARD_REGNO_NREGS (@var{regno},
+@var{mode})} for all @var{regno} values in the class @var{class}.
+
+This macro helps control the handling of multiple-word values
+in the reload pass.
+
+@item CLASS_CANNOT_CHANGE_MODE
+If defined, a C expression for a class that contains registers for
+which the compiler may not change modes arbitrarily.
+
+@item CLASS_CANNOT_CHANGE_MODE_P(@var{from}, @var{to})
+A C expression that is true if, for a register in
+@code{CLASS_CANNOT_CHANGE_MODE}, the requested mode punning is invalid.
+
+For the example, loading 32-bit integer or floating-point objects into
+floating-point registers on the Alpha extends them to 64-bits.
+Therefore loading a 64-bit object and then storing it as a 32-bit object
+does not store the low-order 32-bits, as would be the case for a normal
+register.  Therefore, @file{alpha.h} defines @code{CLASS_CANNOT_CHANGE_MODE}
+as @code{FLOAT_REGS} and @code{CLASS_CANNOT_CHANGE_MODE_P} restricts
+mode changes to same-size modes.
+
+Compare this to IA-64, which extends floating-point values to 82-bits,
+and stores 64-bit integers in a different format than 64-bit doubles.
+Therefore @code{CLASS_CANNOT_CHANGE_MODE_P} is always true.
+@end table
+
+Three other special macros describe which operands fit which constraint
+letters.
+
+@table @code
+@findex CONST_OK_FOR_LETTER_P
+@item CONST_OK_FOR_LETTER_P (@var{value}, @var{c})
+A C expression that defines the machine-dependent operand constraint
+letters (@samp{I}, @samp{J}, @samp{K}, @dots{} @samp{P}) that specify
+particular ranges of integer values.  If @var{c} is one of those
+letters, the expression should check that @var{value}, an integer, is in
+the appropriate range and return 1 if so, 0 otherwise.  If @var{c} is
+not one of those letters, the value should be 0 regardless of
+@var{value}.
+
+@findex CONST_DOUBLE_OK_FOR_LETTER_P
+@item CONST_DOUBLE_OK_FOR_LETTER_P (@var{value}, @var{c})
+A C expression that defines the machine-dependent operand constraint
+letters that specify particular ranges of @code{const_double} values
+(@samp{G} or @samp{H}).
+
+If @var{c} is one of those letters, the expression should check that
+@var{value}, an RTX of code @code{const_double}, is in the appropriate
+range and return 1 if so, 0 otherwise.  If @var{c} is not one of those
+letters, the value should be 0 regardless of @var{value}.
+
+@code{const_double} is used for all floating-point constants and for
+@code{DImode} fixed-point constants.  A given letter can accept either
+or both kinds of values.  It can use @code{GET_MODE} to distinguish
+between these kinds.
+
+@findex EXTRA_CONSTRAINT
+@item EXTRA_CONSTRAINT (@var{value}, @var{c})
+A C expression that defines the optional machine-dependent constraint
+letters that can be used to segregate specific types of operands, usually
+memory references, for the target machine.  Any letter that is not
+elsewhere defined and not matched by @code{REG_CLASS_FROM_LETTER}
+may be used.  Normally this macro will not be defined.
+
+If it is required for a particular target machine, it should return 1
+if @var{value} corresponds to the operand type represented by the
+constraint letter @var{c}.  If @var{c} is not defined as an extra
+constraint, the value returned should be 0 regardless of @var{value}.
+
+For example, on the ROMP, load instructions cannot have their output
+in r0 if the memory reference contains a symbolic address.  Constraint
+letter @samp{Q} is defined as representing a memory address that does
+@emph{not} contain a symbolic address.  An alternative is specified with
+a @samp{Q} constraint on the input and @samp{r} on the output.  The next
+alternative specifies @samp{m} on the input and a register class that
+does not include r0 on the output.
+@end table
+
+@node Stack and Calling
+@section Stack Layout and Calling Conventions
+@cindex calling conventions
+
+@c prevent bad page break with this line
+This describes the stack layout and calling conventions.
+
+@menu
+* Frame Layout::
+* Exception Handling::
+* Stack Checking::
+* Frame Registers::
+* Elimination::
+* Stack Arguments::
+* Register Arguments::
+* Scalar Return::
+* Aggregate Return::
+* Caller Saves::
+* Function Entry::
+* Profiling::
+* Tail Calls::
+@end menu
+
+@node Frame Layout
+@subsection Basic Stack Layout
+@cindex stack frame layout
+@cindex frame layout
+
+@c prevent bad page break with this line
+Here is the basic stack layout.
+
+@table @code
+@findex STACK_GROWS_DOWNWARD
+@item STACK_GROWS_DOWNWARD
+Define this macro if pushing a word onto the stack moves the stack
+pointer to a smaller address.
+
+When we say, ``define this macro if @dots{},'' it means that the
+compiler checks this macro only with @code{#ifdef} so the precise
+definition used does not matter.
+
+@findex STACK_PUSH_CODE
+@item STACK_PUSH_CODE
+
+This macro defines the operation used when something is pushed
+on the stack.  In RTL, a push operation will be
+@code{(set (mem (STACK_PUSH_CODE (reg sp))) ...)}
+
+The choices are @code{PRE_DEC}, @code{POST_DEC}, @code{PRE_INC},
+and @code{POST_INC}.  Which of these is correct depends on
+the stack direction and on whether the stack pointer points
+to the last item on the stack or whether it points to the
+space for the next item on the stack.
+
+The default is @code{PRE_DEC} when @code{STACK_GROWS_DOWNWARD} is
+defined, which is almost always right, and @code{PRE_INC} otherwise,
+which is often wrong.
+
+@findex FRAME_GROWS_DOWNWARD
+@item FRAME_GROWS_DOWNWARD
+Define this macro if the addresses of local variable slots are at negative
+offsets from the frame pointer.
+
+@findex ARGS_GROW_DOWNWARD
+@item ARGS_GROW_DOWNWARD
+Define this macro if successive arguments to a function occupy decreasing
+addresses on the stack.
+
+@findex STARTING_FRAME_OFFSET
+@item STARTING_FRAME_OFFSET
+Offset from the frame pointer to the first local variable slot to be allocated.
+
+If @code{FRAME_GROWS_DOWNWARD}, find the next slot's offset by
+subtracting the first slot's length from @code{STARTING_FRAME_OFFSET}.
+Otherwise, it is found by adding the length of the first slot to the
+value @code{STARTING_FRAME_OFFSET}.
+@c i'm not sure if the above is still correct.. had to change it to get
+@c rid of an overfull.  --mew 2feb93
+
+@findex STACK_POINTER_OFFSET
+@item STACK_POINTER_OFFSET
+Offset from the stack pointer register to the first location at which
+outgoing arguments are placed.  If not specified, the default value of
+zero is used.  This is the proper value for most machines.
+
+If @code{ARGS_GROW_DOWNWARD}, this is the offset to the location above
+the first location at which outgoing arguments are placed.
+
+@findex FIRST_PARM_OFFSET
+@item FIRST_PARM_OFFSET (@var{fundecl})
+Offset from the argument pointer register to the first argument's
+address.  On some machines it may depend on the data type of the
+function.
+
+If @code{ARGS_GROW_DOWNWARD}, this is the offset to the location above
+the first argument's address.
+
+@findex STACK_DYNAMIC_OFFSET
+@item STACK_DYNAMIC_OFFSET (@var{fundecl})
+Offset from the stack pointer register to an item dynamically allocated
+on the stack, e.g., by @code{alloca}.
+
+The default value for this macro is @code{STACK_POINTER_OFFSET} plus the
+length of the outgoing arguments.  The default is correct for most
+machines.  See @file{function.c} for details.
+
+@findex DYNAMIC_CHAIN_ADDRESS
+@item DYNAMIC_CHAIN_ADDRESS (@var{frameaddr})
+A C expression whose value is RTL representing the address in a stack
+frame where the pointer to the caller's frame is stored.  Assume that
+@var{frameaddr} is an RTL expression for the address of the stack frame
+itself.
+
+If you don't define this macro, the default is to return the value
+of @var{frameaddr}---that is, the stack frame address is also the
+address of the stack word that points to the previous frame.
+
+@findex SETUP_FRAME_ADDRESSES
+@item SETUP_FRAME_ADDRESSES
+If defined, a C expression that produces the machine-specific code to
+setup the stack so that arbitrary frames can be accessed.  For example,
+on the Sparc, we must flush all of the register windows to the stack
+before we can access arbitrary stack frames.  You will seldom need to
+define this macro.
+
+@findex BUILTIN_SETJMP_FRAME_VALUE
+@item BUILTIN_SETJMP_FRAME_VALUE
+If defined, a C expression that contains an rtx that is used to store
+the address of the current frame into the built in @code{setjmp} buffer.
+The default value, @code{virtual_stack_vars_rtx}, is correct for most
+machines.  One reason you may need to define this macro is if
+@code{hard_frame_pointer_rtx} is the appropriate value on your machine.
+
+@findex RETURN_ADDR_RTX
+@item RETURN_ADDR_RTX (@var{count}, @var{frameaddr})
+A C expression whose value is RTL representing the value of the return
+address for the frame @var{count} steps up from the current frame, after
+the prologue.  @var{frameaddr} is the frame pointer of the @var{count}
+frame, or the frame pointer of the @var{count} @minus{} 1 frame if
+@code{RETURN_ADDR_IN_PREVIOUS_FRAME} is defined.
+
+The value of the expression must always be the correct address when
+@var{count} is zero, but may be @code{NULL_RTX} if there is not way to
+determine the return address of other frames.
+
+@findex RETURN_ADDR_IN_PREVIOUS_FRAME
+@item RETURN_ADDR_IN_PREVIOUS_FRAME
+Define this if the return address of a particular stack frame is accessed
+from the frame pointer of the previous stack frame.
+
+@findex INCOMING_RETURN_ADDR_RTX
+@item INCOMING_RETURN_ADDR_RTX
+A C expression whose value is RTL representing the location of the
+incoming return address at the beginning of any function, before the
+prologue.  This RTL is either a @code{REG}, indicating that the return
+value is saved in @samp{REG}, or a @code{MEM} representing a location in
+the stack.
+
+You only need to define this macro if you want to support call frame
+debugging information like that provided by DWARF 2.
+
+If this RTL is a @code{REG}, you should also define
+@code{DWARF_FRAME_RETURN_COLUMN} to @code{DWARF_FRAME_REGNUM (REGNO)}.
+
+@findex INCOMING_FRAME_SP_OFFSET
+@item INCOMING_FRAME_SP_OFFSET
+A C expression whose value is an integer giving the offset, in bytes,
+from the value of the stack pointer register to the top of the stack
+frame at the beginning of any function, before the prologue.  The top of
+the frame is defined to be the value of the stack pointer in the
+previous frame, just before the call instruction.
+
+You only need to define this macro if you want to support call frame
+debugging information like that provided by DWARF 2.
+
+@findex ARG_POINTER_CFA_OFFSET
+@item ARG_POINTER_CFA_OFFSET (@var{fundecl})
+A C expression whose value is an integer giving the offset, in bytes,
+from the argument pointer to the canonical frame address (cfa).  The
+final value should coincide with that calculated by
+@code{INCOMING_FRAME_SP_OFFSET}.  Which is unfortunately not usable
+during virtual register instantiation.
+
+The default value for this macro is @code{FIRST_PARM_OFFSET (fundecl)},
+which is correct for most machines; in general, the arguments are found
+immediately before the stack frame.  Note that this is not the case on
+some targets that save registers into the caller's frame, such as SPARC
+and rs6000, and so such targets need to define this macro.
+
+You only need to define this macro if the default is incorrect, and you
+want to support call frame debugging information like that provided by
+DWARF 2.
+
+@findex SMALL_STACK
+@item SMALL_STACK
+Define this macro if the stack size for the target is very small.  This
+has the effect of disabling gcc's built-in @samp{alloca}, though
+@samp{__builtin_alloca} is not affected.
+@end table
+
+@node Exception Handling
+@subsection Exception Handling Support
+@cindex exception handling
+
+@table @code
+@findex EH_RETURN_DATA_REGNO
+@item EH_RETURN_DATA_REGNO (@var{N})
+A C expression whose value is the @var{N}th register number used for
+data by exception handlers, or @code{INVALID_REGNUM} if fewer than
+@var{N} registers are usable.
+
+The exception handling library routines communicate with the exception
+handlers via a set of agreed upon registers.  Ideally these registers
+should be call-clobbered; it is possible to use call-saved registers,
+but may negatively impact code size.  The target must support at least
+2 data registers, but should define 4 if there are enough free registers.
+
+You must define this macro if you want to support call frame exception
+handling like that provided by DWARF 2.
+
+@findex EH_RETURN_STACKADJ_RTX
+@item EH_RETURN_STACKADJ_RTX
+A C expression whose value is RTL representing a location in which
+to store a stack adjustment to be applied before function return.
+This is used to unwind the stack to an exception handler's call frame.
+It will be assigned zero on code paths that return normally.
+
+Typically this is a call-clobbered hard register that is otherwise
+untouched by the epilogue, but could also be a stack slot.
+
+You must define this macro if you want to support call frame exception
+handling like that provided by DWARF 2.
+
+@findex EH_RETURN_HANDLER_RTX
+@item EH_RETURN_HANDLER_RTX
+A C expression whose value is RTL representing a location in which
+to store the address of an exception handler to which we should
+return.  It will not be assigned on code paths that return normally.
+
+Typically this is the location in the call frame at which the normal
+return address is stored.  For targets that return by popping an
+address off the stack, this might be a memory address just below
+the @emph{target} call frame rather than inside the current call
+frame.  @code{EH_RETURN_STACKADJ_RTX} will have already been assigned,
+so it may be used to calculate the location of the target call frame.
+
+Some targets have more complex requirements than storing to an
+address calculable during initial code generation.  In that case
+the @code{eh_return} instruction pattern should be used instead.
+
+If you want to support call frame exception handling, you must
+define either this macro or the @code{eh_return} instruction pattern.
+
+@findex ASM_PREFERRED_EH_DATA_FORMAT
+@item ASM_PREFERRED_EH_DATA_FORMAT(@var{code}, @var{global})
+This macro chooses the encoding of pointers embedded in the exception
+handling sections.  If at all possible, this should be defined such
+that the exception handling section will not require dynamic relocations,
+and so may be read-only.
+
+@var{code} is 0 for data, 1 for code labels, 2 for function pointers.
+@var{global} is true if the symbol may be affected by dynamic relocations.
+The macro should return a combination of the @code{DW_EH_PE_*} defines
+as found in @file{dwarf2.h}.
+
+If this macro is not defined, pointers will not be encoded but
+represented directly.
+
+@findex ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX
+@item ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX(@var{file}, @var{encoding}, @var{size}, @var{addr}, @var{done})
+This macro allows the target to emit whatever special magic is required
+to represent the encoding chosen by @code{ASM_PREFERRED_EH_DATA_FORMAT}.
+Generic code takes care of pc-relative and indirect encodings; this must
+be defined if the target uses text-relative or data-relative encodings.
+
+This is a C statement that branches to @var{done} if the format was
+handled.  @var{encoding} is the format chosen, @var{size} is the number
+of bytes that the format occupies, @var{addr} is the @code{SYMBOL_REF}
+to be emitted.
+
+@findex MD_FALLBACK_FRAME_STATE_FOR
+@item MD_FALLBACK_FRAME_STATE_FOR(@var{context}, @var{fs}, @var{success})
+This macro allows the target to add cpu and operating system specific
+code to the call-frame unwinder for use when there is no unwind data
+available.  The most common reason to implement this macro is to unwind
+through signal frames.
+
+This macro is called from @code{uw_frame_state_for} in @file{unwind-dw2.c}
+and @file{unwind-ia64.c}.  @var{context} is an @code{_Unwind_Context};
+@var{fs} is an @code{_Unwind_FrameState}.  Examine @code{context->ra}
+for the address of the code being executed and @code{context->cfa} for
+the stack pointer value.  If the frame can be decoded, the register save
+addresses should be updated in @var{fs} and the macro should branch to
+@var{success}.  If the frame cannot be decoded, the macro should do 
+nothing.
+@end table
+
+@node Stack Checking
+@subsection Specifying How Stack Checking is Done
+
+GCC will check that stack references are within the boundaries of
+the stack, if the @option{-fstack-check} is specified, in one of three ways:
+
+@enumerate
+@item
+If the value of the @code{STACK_CHECK_BUILTIN} macro is nonzero, GCC
+will assume that you have arranged for stack checking to be done at
+appropriate places in the configuration files, e.g., in
+@code{TARGET_ASM_FUNCTION_PROLOGUE}.  GCC will do not other special
+processing.
+
+@item
+If @code{STACK_CHECK_BUILTIN} is zero and you defined a named pattern
+called @code{check_stack} in your @file{md} file, GCC will call that
+pattern with one argument which is the address to compare the stack
+value against.  You must arrange for this pattern to report an error if
+the stack pointer is out of range.
+
+@item
+If neither of the above are true, GCC will generate code to periodically
+``probe'' the stack pointer using the values of the macros defined below.
+@end enumerate
+
+Normally, you will use the default values of these macros, so GCC
+will use the third approach.
+
+@table @code
+@findex STACK_CHECK_BUILTIN
+@item STACK_CHECK_BUILTIN
+A nonzero value if stack checking is done by the configuration files in a
+machine-dependent manner.  You should define this macro if stack checking
+is require by the ABI of your machine or if you would like to have to stack
+checking in some more efficient way than GCC's portable approach.
+The default value of this macro is zero.
+
+@findex STACK_CHECK_PROBE_INTERVAL
+@item STACK_CHECK_PROBE_INTERVAL
+An integer representing the interval at which GCC must generate stack
+probe instructions.  You will normally define this macro to be no larger
+than the size of the ``guard pages'' at the end of a stack area.  The
+default value of 4096 is suitable for most systems.
+
+@findex STACK_CHECK_PROBE_LOAD
+@item STACK_CHECK_PROBE_LOAD
+A integer which is nonzero if GCC should perform the stack probe
+as a load instruction and zero if GCC should use a store instruction.
+The default is zero, which is the most efficient choice on most systems.
+
+@findex STACK_CHECK_PROTECT
+@item STACK_CHECK_PROTECT
+The number of bytes of stack needed to recover from a stack overflow,
+for languages where such a recovery is supported.  The default value of
+75 words should be adequate for most machines.
+
+@findex STACK_CHECK_MAX_FRAME_SIZE
+@item STACK_CHECK_MAX_FRAME_SIZE
+The maximum size of a stack frame, in bytes.  GCC will generate probe
+instructions in non-leaf functions to ensure at least this many bytes of
+stack are available.  If a stack frame is larger than this size, stack
+checking will not be reliable and GCC will issue a warning.  The
+default is chosen so that GCC only generates one instruction on most
+systems.  You should normally not change the default value of this macro.
+
+@findex STACK_CHECK_FIXED_FRAME_SIZE
+@item STACK_CHECK_FIXED_FRAME_SIZE
+GCC uses this value to generate the above warning message.  It
+represents the amount of fixed frame used by a function, not including
+space for any callee-saved registers, temporaries and user variables.
+You need only specify an upper bound for this amount and will normally
+use the default of four words.
+
+@findex STACK_CHECK_MAX_VAR_SIZE
+@item STACK_CHECK_MAX_VAR_SIZE
+The maximum size, in bytes, of an object that GCC will place in the
+fixed area of the stack frame when the user specifies
+@option{-fstack-check}.
+GCC computed the default from the values of the above macros and you will
+normally not need to override that default.
+@end table
+
+@need 2000
+@node Frame Registers
+@subsection Registers That Address the Stack Frame
+
+@c prevent bad page break with this line
+This discusses registers that address the stack frame.
+
+@table @code
+@findex STACK_POINTER_REGNUM
+@item STACK_POINTER_REGNUM
+The register number of the stack pointer register, which must also be a
+fixed register according to @code{FIXED_REGISTERS}.  On most machines,
+the hardware determines which register this is.
+
+@findex FRAME_POINTER_REGNUM
+@item FRAME_POINTER_REGNUM
+The register number of the frame pointer register, which is used to
+access automatic variables in the stack frame.  On some machines, the
+hardware determines which register this is.  On other machines, you can
+choose any register you wish for this purpose.
+
+@findex HARD_FRAME_POINTER_REGNUM
+@item HARD_FRAME_POINTER_REGNUM
+On some machines the offset between the frame pointer and starting
+offset of the automatic variables is not known until after register
+allocation has been done (for example, because the saved registers are
+between these two locations).  On those machines, define
+@code{FRAME_POINTER_REGNUM} the number of a special, fixed register to
+be used internally until the offset is known, and define
+@code{HARD_FRAME_POINTER_REGNUM} to be the actual hard register number
+used for the frame pointer.
+
+You should define this macro only in the very rare circumstances when it
+is not possible to calculate the offset between the frame pointer and
+the automatic variables until after register allocation has been
+completed.  When this macro is defined, you must also indicate in your
+definition of @code{ELIMINABLE_REGS} how to eliminate
+@code{FRAME_POINTER_REGNUM} into either @code{HARD_FRAME_POINTER_REGNUM}
+or @code{STACK_POINTER_REGNUM}.
+
+Do not define this macro if it would be the same as
+@code{FRAME_POINTER_REGNUM}.
+
+@findex ARG_POINTER_REGNUM
+@item ARG_POINTER_REGNUM
+The register number of the arg pointer register, which is used to access
+the function's argument list.  On some machines, this is the same as the
+frame pointer register.  On some machines, the hardware determines which
+register this is.  On other machines, you can choose any register you
+wish for this purpose.  If this is not the same register as the frame
+pointer register, then you must mark it as a fixed register according to
+@code{FIXED_REGISTERS}, or arrange to be able to eliminate it
+(@pxref{Elimination}).
+
+@findex RETURN_ADDRESS_POINTER_REGNUM
+@item RETURN_ADDRESS_POINTER_REGNUM
+The register number of the return address pointer register, which is used to
+access the current function's return address from the stack.  On some
+machines, the return address is not at a fixed offset from the frame
+pointer or stack pointer or argument pointer.  This register can be defined
+to point to the return address on the stack, and then be converted by
+@code{ELIMINABLE_REGS} into either the frame pointer or stack pointer.
+
+Do not define this macro unless there is no other way to get the return
+address from the stack.
+
+@findex STATIC_CHAIN_REGNUM
+@findex STATIC_CHAIN_INCOMING_REGNUM
+@item STATIC_CHAIN_REGNUM
+@itemx STATIC_CHAIN_INCOMING_REGNUM
+Register numbers used for passing a function's static chain pointer.  If
+register windows are used, the register number as seen by the called
+function is @code{STATIC_CHAIN_INCOMING_REGNUM}, while the register
+number as seen by the calling function is @code{STATIC_CHAIN_REGNUM}.  If
+these registers are the same, @code{STATIC_CHAIN_INCOMING_REGNUM} need
+not be defined.
+
+The static chain register need not be a fixed register.
+
+If the static chain is passed in memory, these macros should not be
+defined; instead, the next two macros should be defined.
+
+@findex STATIC_CHAIN
+@findex STATIC_CHAIN_INCOMING
+@item STATIC_CHAIN
+@itemx STATIC_CHAIN_INCOMING
+If the static chain is passed in memory, these macros provide rtx giving
+@code{mem} expressions that denote where they are stored.
+@code{STATIC_CHAIN} and @code{STATIC_CHAIN_INCOMING} give the locations
+as seen by the calling and called functions, respectively.  Often the former
+will be at an offset from the stack pointer and the latter at an offset from
+the frame pointer.
+
+@findex stack_pointer_rtx
+@findex frame_pointer_rtx
+@findex arg_pointer_rtx
+The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and
+@code{arg_pointer_rtx} will have been initialized prior to the use of these
+macros and should be used to refer to those items.
+
+If the static chain is passed in a register, the two previous macros should
+be defined instead.
+
+@findex DWARF_FRAME_REGISTERS
+@item DWARF_FRAME_REGISTERS
+This macro specifies the maximum number of hard registers that can be
+saved in a call frame.  This is used to size data structures used in
+DWARF2 exception handling.
+
+Prior to GCC 3.0, this macro was needed in order to establish a stable
+exception handling ABI in the face of adding new hard registers for ISA
+extensions.  In GCC 3.0 and later, the EH ABI is insulated from changes
+in the number of hard registers.  Nevertheless, this macro can still be
+used to reduce the runtime memory requirements of the exception handling
+routines, which can be substantial if the ISA contains a lot of
+registers that are not call-saved.
+
+If this macro is not defined, it defaults to
+@code{FIRST_PSEUDO_REGISTER}.
+
+@findex PRE_GCC3_DWARF_FRAME_REGISTERS
+@item PRE_GCC3_DWARF_FRAME_REGISTERS
+
+This macro is similar to @code{DWARF_FRAME_REGISTERS}, but is provided
+for backward compatibility in pre GCC 3.0 compiled code.
+
+If this macro is not defined, it defaults to
+@code{DWARF_FRAME_REGISTERS}.
+
+@end table
+
+@node Elimination
+@subsection Eliminating Frame Pointer and Arg Pointer
+
+@c prevent bad page break with this line
+This is about eliminating the frame pointer and arg pointer.
+
+@table @code
+@findex FRAME_POINTER_REQUIRED
+@item FRAME_POINTER_REQUIRED
+A C expression which is nonzero if a function must have and use a frame
+pointer.  This expression is evaluated  in the reload pass.  If its value is
+nonzero the function will have a frame pointer.
+
+The expression can in principle examine the current function and decide
+according to the facts, but on most machines the constant 0 or the
+constant 1 suffices.  Use 0 when the machine allows code to be generated
+with no frame pointer, and doing so saves some time or space.  Use 1
+when there is no possible advantage to avoiding a frame pointer.
+
+In certain cases, the compiler does not know how to produce valid code
+without a frame pointer.  The compiler recognizes those cases and
+automatically gives the function a frame pointer regardless of what
+@code{FRAME_POINTER_REQUIRED} says.  You don't need to worry about
+them.
+
+In a function that does not require a frame pointer, the frame pointer
+register can be allocated for ordinary usage, unless you mark it as a
+fixed register.  See @code{FIXED_REGISTERS} for more information.
+
+@findex INITIAL_FRAME_POINTER_OFFSET
+@findex get_frame_size
+@item INITIAL_FRAME_POINTER_OFFSET (@var{depth-var})
+A C statement to store in the variable @var{depth-var} the difference
+between the frame pointer and the stack pointer values immediately after
+the function prologue.  The value would be computed from information
+such as the result of @code{get_frame_size ()} and the tables of
+registers @code{regs_ever_live} and @code{call_used_regs}.
+
+If @code{ELIMINABLE_REGS} is defined, this macro will be not be used and
+need not be defined.  Otherwise, it must be defined even if
+@code{FRAME_POINTER_REQUIRED} is defined to always be true; in that
+case, you may set @var{depth-var} to anything.
+
+@findex ELIMINABLE_REGS
+@item ELIMINABLE_REGS
+If defined, this macro specifies a table of register pairs used to
+eliminate unneeded registers that point into the stack frame.  If it is not
+defined, the only elimination attempted by the compiler is to replace
+references to the frame pointer with references to the stack pointer.
+
+The definition of this macro is a list of structure initializations, each
+of which specifies an original and replacement register.
+
+On some machines, the position of the argument pointer is not known until
+the compilation is completed.  In such a case, a separate hard register
+must be used for the argument pointer.  This register can be eliminated by
+replacing it with either the frame pointer or the argument pointer,
+depending on whether or not the frame pointer has been eliminated.
+
+In this case, you might specify:
+@example
+#define ELIMINABLE_REGS  \
+@{@{ARG_POINTER_REGNUM, STACK_POINTER_REGNUM@}, \
+ @{ARG_POINTER_REGNUM, FRAME_POINTER_REGNUM@}, \
+ @{FRAME_POINTER_REGNUM, STACK_POINTER_REGNUM@}@}
+@end example
+
+Note that the elimination of the argument pointer with the stack pointer is
+specified first since that is the preferred elimination.
+
+@findex CAN_ELIMINATE
+@item CAN_ELIMINATE (@var{from-reg}, @var{to-reg})
+A C expression that returns nonzero if the compiler is allowed to try
+to replace register number @var{from-reg} with register number
+@var{to-reg}.  This macro need only be defined if @code{ELIMINABLE_REGS}
+is defined, and will usually be the constant 1, since most of the cases
+preventing register elimination are things that the compiler already
+knows about.
+
+@findex INITIAL_ELIMINATION_OFFSET
+@item INITIAL_ELIMINATION_OFFSET (@var{from-reg}, @var{to-reg}, @var{offset-var})
+This macro is similar to @code{INITIAL_FRAME_POINTER_OFFSET}.  It
+specifies the initial difference between the specified pair of
+registers.  This macro must be defined if @code{ELIMINABLE_REGS} is
+defined.
+@end table
+
+@node Stack Arguments
+@subsection Passing Function Arguments on the Stack
+@cindex arguments on stack
+@cindex stack arguments
+
+The macros in this section control how arguments are passed
+on the stack.  See the following section for other macros that
+control passing certain arguments in registers.
+
+@table @code
+@findex PROMOTE_PROTOTYPES
+@item PROMOTE_PROTOTYPES
+A C expression whose value is nonzero if an argument declared in
+a prototype as an integral type smaller than @code{int} should
+actually be passed as an @code{int}.  In addition to avoiding
+errors in certain cases of mismatch, it also makes for better
+code on certain machines.  If the macro is not defined in target
+header files, it defaults to 0.
+
+@findex PUSH_ARGS
+@item PUSH_ARGS
+A C expression.  If nonzero, push insns will be used to pass
+outgoing arguments.
+If the target machine does not have a push instruction, set it to zero.
+That directs GCC to use an alternate strategy: to
+allocate the entire argument block and then store the arguments into
+it.  When @code{PUSH_ARGS} is nonzero, @code{PUSH_ROUNDING} must be defined too.
+On some machines, the definition
+
+@findex PUSH_ROUNDING
+@item PUSH_ROUNDING (@var{npushed})
+A C expression that is the number of bytes actually pushed onto the
+stack when an instruction attempts to push @var{npushed} bytes.
+
+On some machines, the definition
+
+@example
+#define PUSH_ROUNDING(BYTES) (BYTES)
+@end example
+
+@noindent
+will suffice.  But on other machines, instructions that appear
+to push one byte actually push two bytes in an attempt to maintain
+alignment.  Then the definition should be
+
+@example
+#define PUSH_ROUNDING(BYTES) (((BYTES) + 1) & ~1)
+@end example
+
+@findex ACCUMULATE_OUTGOING_ARGS
+@findex current_function_outgoing_args_size
+@item ACCUMULATE_OUTGOING_ARGS
+A C expression.  If nonzero, the maximum amount of space required for outgoing arguments
+will be computed and placed into the variable
+@code{current_function_outgoing_args_size}.  No space will be pushed
+onto the stack for each call; instead, the function prologue should
+increase the stack frame size by this amount.
+
+Setting both @code{PUSH_ARGS} and @code{ACCUMULATE_OUTGOING_ARGS}
+is not proper.
+
+@findex REG_PARM_STACK_SPACE
+@item REG_PARM_STACK_SPACE (@var{fndecl})
+Define this macro if functions should assume that stack space has been
+allocated for arguments even when their values are passed in
+registers.
+
+The value of this macro is the size, in bytes, of the area reserved for
+arguments passed in registers for the function represented by @var{fndecl},
+which can be zero if GCC is calling a library function.
+
+This space can be allocated by the caller, or be a part of the
+machine-dependent stack frame: @code{OUTGOING_REG_PARM_STACK_SPACE} says
+which.
+@c above is overfull.  not sure what to do.  --mew 5feb93  did
+@c something, not sure if it looks good.  --mew 10feb93
+
+@findex MAYBE_REG_PARM_STACK_SPACE
+@findex FINAL_REG_PARM_STACK_SPACE
+@item MAYBE_REG_PARM_STACK_SPACE
+@itemx FINAL_REG_PARM_STACK_SPACE (@var{const_size}, @var{var_size})
+Define these macros in addition to the one above if functions might
+allocate stack space for arguments even when their values are passed
+in registers.  These should be used when the stack space allocated
+for arguments in registers is not a simple constant independent of the
+function declaration.
+
+The value of the first macro is the size, in bytes, of the area that
+we should initially assume would be reserved for arguments passed in registers.
+
+The value of the second macro is the actual size, in bytes, of the area
+that will be reserved for arguments passed in registers.  This takes two
+arguments: an integer representing the number of bytes of fixed sized
+arguments on the stack, and a tree representing the number of bytes of
+variable sized arguments on the stack.
+
+When these macros are defined, @code{REG_PARM_STACK_SPACE} will only be
+called for libcall functions, the current function, or for a function
+being called when it is known that such stack space must be allocated.
+In each case this value can be easily computed.
+
+When deciding whether a called function needs such stack space, and how
+much space to reserve, GCC uses these two macros instead of
+@code{REG_PARM_STACK_SPACE}.
+
+@findex OUTGOING_REG_PARM_STACK_SPACE
+@item OUTGOING_REG_PARM_STACK_SPACE
+Define this if it is the responsibility of the caller to allocate the area
+reserved for arguments passed in registers.
+
+If @code{ACCUMULATE_OUTGOING_ARGS} is defined, this macro controls
+whether the space for these arguments counts in the value of
+@code{current_function_outgoing_args_size}.
+
+@findex STACK_PARMS_IN_REG_PARM_AREA
+@item STACK_PARMS_IN_REG_PARM_AREA
+Define this macro if @code{REG_PARM_STACK_SPACE} is defined, but the
+stack parameters don't skip the area specified by it.
+@c i changed this, makes more sens and it should have taken care of the
+@c overfull.. not as specific, tho.  --mew 5feb93
+
+Normally, when a parameter is not passed in registers, it is placed on the
+stack beyond the @code{REG_PARM_STACK_SPACE} area.  Defining this macro
+suppresses this behavior and causes the parameter to be passed on the
+stack in its natural location.
+
+@findex RETURN_POPS_ARGS
+@item RETURN_POPS_ARGS (@var{fundecl}, @var{funtype}, @var{stack-size})
+A C expression that should indicate the number of bytes of its own
+arguments that a function pops on returning, or 0 if the
+function pops no arguments and the caller must therefore pop them all
+after the function returns.
+
+@var{fundecl} is a C variable whose value is a tree node that describes
+the function in question.  Normally it is a node of type
+@code{FUNCTION_DECL} that describes the declaration of the function.
+From this you can obtain the @code{DECL_ATTRIBUTES} of the function.
+
+@var{funtype} is a C variable whose value is a tree node that
+describes the function in question.  Normally it is a node of type
+@code{FUNCTION_TYPE} that describes the data type of the function.
+From this it is possible to obtain the data types of the value and
+arguments (if known).
+
+When a call to a library function is being considered, @var{fundecl}
+will contain an identifier node for the library function.  Thus, if
+you need to distinguish among various library functions, you can do so
+by their names.  Note that ``library function'' in this context means
+a function used to perform arithmetic, whose name is known specially
+in the compiler and was not mentioned in the C code being compiled.
+
+@var{stack-size} is the number of bytes of arguments passed on the
+stack.  If a variable number of bytes is passed, it is zero, and
+argument popping will always be the responsibility of the calling function.
+
+On the VAX, all functions always pop their arguments, so the definition
+of this macro is @var{stack-size}.  On the 68000, using the standard
+calling convention, no functions pop their arguments, so the value of
+the macro is always 0 in this case.  But an alternative calling
+convention is available in which functions that take a fixed number of
+arguments pop them but other functions (such as @code{printf}) pop
+nothing (the caller pops all).  When this convention is in use,
+@var{funtype} is examined to determine whether a function takes a fixed
+number of arguments.
+@end table
+
+@node Register Arguments
+@subsection Passing Arguments in Registers
+@cindex arguments in registers
+@cindex registers arguments
+
+This section describes the macros which let you control how various
+types of arguments are passed in registers or how they are arranged in
+the stack.
+
+@table @code
+@findex FUNCTION_ARG
+@item FUNCTION_ARG (@var{cum}, @var{mode}, @var{type}, @var{named})
+A C expression that controls whether a function argument is passed
+in a register, and which register.
+
+The arguments are @var{cum}, which summarizes all the previous
+arguments; @var{mode}, the machine mode of the argument; @var{type},
+the data type of the argument as a tree node or 0 if that is not known
+(which happens for C support library functions); and @var{named},
+which is 1 for an ordinary argument and 0 for nameless arguments that
+correspond to @samp{@dots{}} in the called function's prototype.
+@var{type} can be an incomplete type if a syntax error has previously
+occurred.
+
+The value of the expression is usually either a @code{reg} RTX for the
+hard register in which to pass the argument, or zero to pass the
+argument on the stack.
+
+For machines like the VAX and 68000, where normally all arguments are
+pushed, zero suffices as a definition.
+
+The value of the expression can also be a @code{parallel} RTX@.  This is
+used when an argument is passed in multiple locations.  The mode of the
+of the @code{parallel} should be the mode of the entire argument.  The
+@code{parallel} holds any number of @code{expr_list} pairs; each one
+describes where part of the argument is passed.  In each
+@code{expr_list} the first operand must be a @code{reg} RTX for the hard
+register in which to pass this part of the argument, and the mode of the
+register RTX indicates how large this part of the argument is.  The
+second operand of the @code{expr_list} is a @code{const_int} which gives
+the offset in bytes into the entire argument of where this part starts.
+As a special exception the first @code{expr_list} in the @code{parallel}
+RTX may have a first operand of zero.  This indicates that the entire
+argument is also stored on the stack.
+
+The last time this macro is called, it is called with @code{MODE ==
+VOIDmode}, and its result is passed to the @code{call} or @code{call_value}
+pattern as operands 2 and 3 respectively.
+
+@cindex @file{stdarg.h} and register arguments
+The usual way to make the ISO library @file{stdarg.h} work on a machine
+where some arguments are usually passed in registers, is to cause
+nameless arguments to be passed on the stack instead.  This is done
+by making @code{FUNCTION_ARG} return 0 whenever @var{named} is 0.
+
+@cindex @code{MUST_PASS_IN_STACK}, and @code{FUNCTION_ARG}
+@cindex @code{REG_PARM_STACK_SPACE}, and @code{FUNCTION_ARG}
+You may use the macro @code{MUST_PASS_IN_STACK (@var{mode}, @var{type})}
+in the definition of this macro to determine if this argument is of a
+type that must be passed in the stack.  If @code{REG_PARM_STACK_SPACE}
+is not defined and @code{FUNCTION_ARG} returns nonzero for such an
+argument, the compiler will abort.  If @code{REG_PARM_STACK_SPACE} is
+defined, the argument will be computed in the stack and then loaded into
+a register.
+
+@findex MUST_PASS_IN_STACK
+@item MUST_PASS_IN_STACK (@var{mode}, @var{type})
+Define as a C expression that evaluates to nonzero if we do not know how
+to pass TYPE solely in registers.  The file @file{expr.h} defines a
+definition that is usually appropriate, refer to @file{expr.h} for additional
+documentation.
+
+@findex FUNCTION_INCOMING_ARG
+@item FUNCTION_INCOMING_ARG (@var{cum}, @var{mode}, @var{type}, @var{named})
+Define this macro if the target machine has ``register windows'', so
+that the register in which a function sees an arguments is not
+necessarily the same as the one in which the caller passed the
+argument.
+
+For such machines, @code{FUNCTION_ARG} computes the register in which
+the caller passes the value, and @code{FUNCTION_INCOMING_ARG} should
+be defined in a similar fashion to tell the function being called
+where the arguments will arrive.
+
+If @code{FUNCTION_INCOMING_ARG} is not defined, @code{FUNCTION_ARG}
+serves both purposes.
+
+@findex FUNCTION_ARG_PARTIAL_NREGS
+@item FUNCTION_ARG_PARTIAL_NREGS (@var{cum}, @var{mode}, @var{type}, @var{named})
+A C expression for the number of words, at the beginning of an
+argument, that must be put in registers.  The value must be zero for
+arguments that are passed entirely in registers or that are entirely
+pushed on the stack.
+
+On some machines, certain arguments must be passed partially in
+registers and partially in memory.  On these machines, typically the
+first @var{n} words of arguments are passed in registers, and the rest
+on the stack.  If a multi-word argument (a @code{double} or a
+structure) crosses that boundary, its first few words must be passed
+in registers and the rest must be pushed.  This macro tells the
+compiler when this occurs, and how many of the words should go in
+registers.
+
+@code{FUNCTION_ARG} for these arguments should return the first
+register to be used by the caller for this argument; likewise
+@code{FUNCTION_INCOMING_ARG}, for the called function.
+
+@findex FUNCTION_ARG_PASS_BY_REFERENCE
+@item FUNCTION_ARG_PASS_BY_REFERENCE (@var{cum}, @var{mode}, @var{type}, @var{named})
+A C expression that indicates when an argument must be passed by reference.
+If nonzero for an argument, a copy of that argument is made in memory and a
+pointer to the argument is passed instead of the argument itself.
+The pointer is passed in whatever way is appropriate for passing a pointer
+to that type.
+
+On machines where @code{REG_PARM_STACK_SPACE} is not defined, a suitable
+definition of this macro might be
+@smallexample
+#define FUNCTION_ARG_PASS_BY_REFERENCE\
+(CUM, MODE, TYPE, NAMED)  \
+  MUST_PASS_IN_STACK (MODE, TYPE)
+@end smallexample
+@c this is *still* too long.  --mew 5feb93
+
+@findex FUNCTION_ARG_CALLEE_COPIES
+@item FUNCTION_ARG_CALLEE_COPIES (@var{cum}, @var{mode}, @var{type}, @var{named})
+If defined, a C expression that indicates when it is the called function's
+responsibility to make a copy of arguments passed by invisible reference.
+Normally, the caller makes a copy and passes the address of the copy to the
+routine being called.  When @code{FUNCTION_ARG_CALLEE_COPIES} is defined and is
+nonzero, the caller does not make a copy.  Instead, it passes a pointer to the
+``live'' value.  The called function must not modify this value.  If it can be
+determined that the value won't be modified, it need not make a copy;
+otherwise a copy must be made.
+
+@findex FUNCTION_ARG_REG_LITTLE_ENDIAN
+@item FUNCTION_ARG_REG_LITTLE_ENDIAN
+If defined TRUE on a big-endian system then structure arguments passed
+(and returned) in registers are passed in a little-endian manner instead of
+the big-endian manner.  On the HP-UX IA64 and PA64 platforms structures are
+aligned differently then integral values and setting this value to true will
+allow for the special handling of structure arguments and return values.
+
+@findex CUMULATIVE_ARGS
+@item CUMULATIVE_ARGS
+A C type for declaring a variable that is used as the first argument of
+@code{FUNCTION_ARG} and other related values.  For some target machines,
+the type @code{int} suffices and can hold the number of bytes of
+argument so far.
+
+There is no need to record in @code{CUMULATIVE_ARGS} anything about the
+arguments that have been passed on the stack.  The compiler has other
+variables to keep track of that.  For target machines on which all
+arguments are passed on the stack, there is no need to store anything in
+@code{CUMULATIVE_ARGS}; however, the data structure must exist and
+should not be empty, so use @code{int}.
+
+@findex INIT_CUMULATIVE_ARGS
+@item INIT_CUMULATIVE_ARGS (@var{cum}, @var{fntype}, @var{libname}, @var{indirect})
+A C statement (sans semicolon) for initializing the variable @var{cum}
+for the state at the beginning of the argument list.  The variable has
+type @code{CUMULATIVE_ARGS}.  The value of @var{fntype} is the tree node
+for the data type of the function which will receive the args, or 0
+if the args are to a compiler support library function.  The value of
+@var{indirect} is nonzero when processing an indirect call, for example
+a call through a function pointer.  The value of @var{indirect} is zero
+for a call to an explicitly named function, a library function call, or when
+@code{INIT_CUMULATIVE_ARGS} is used to find arguments for the function
+being compiled.
+
+When processing a call to a compiler support library function,
+@var{libname} identifies which one.  It is a @code{symbol_ref} rtx which
+contains the name of the function, as a string.  @var{libname} is 0 when
+an ordinary C function call is being processed.  Thus, each time this
+macro is called, either @var{libname} or @var{fntype} is nonzero, but
+never both of them at once.
+
+@findex INIT_CUMULATIVE_LIBCALL_ARGS
+@item INIT_CUMULATIVE_LIBCALL_ARGS (@var{cum}, @var{mode}, @var{libname})
+Like @code{INIT_CUMULATIVE_ARGS} but only used for outgoing libcalls,
+it gets a @code{MODE} argument instead of @var{fntype}, that would be
+@code{NULL}.  @var{indirect} would always be zero, too.  If this macro
+is not defined, @code{INIT_CUMULATIVE_ARGS (cum, NULL_RTX, libname,
+0)} is used instead.
+
+@findex INIT_CUMULATIVE_INCOMING_ARGS
+@item INIT_CUMULATIVE_INCOMING_ARGS (@var{cum}, @var{fntype}, @var{libname})
+Like @code{INIT_CUMULATIVE_ARGS} but overrides it for the purposes of
+finding the arguments for the function being compiled.  If this macro is
+undefined, @code{INIT_CUMULATIVE_ARGS} is used instead.
+
+The value passed for @var{libname} is always 0, since library routines
+with special calling conventions are never compiled with GCC@.  The
+argument @var{libname} exists for symmetry with
+@code{INIT_CUMULATIVE_ARGS}.
+@c could use "this macro" in place of @code{INIT_CUMULATIVE_ARGS}, maybe.
+@c --mew 5feb93   i switched the order of the sentences.  --mew 10feb93
+
+@findex FUNCTION_ARG_ADVANCE
+@item FUNCTION_ARG_ADVANCE (@var{cum}, @var{mode}, @var{type}, @var{named})
+A C statement (sans semicolon) to update the summarizer variable
+@var{cum} to advance past an argument in the argument list.  The
+values @var{mode}, @var{type} and @var{named} describe that argument.
+Once this is done, the variable @var{cum} is suitable for analyzing
+the @emph{following} argument with @code{FUNCTION_ARG}, etc.
+
+This macro need not do anything if the argument in question was passed
+on the stack.  The compiler knows how to track the amount of stack space
+used for arguments without any special help.
+
+@findex FUNCTION_ARG_PADDING
+@item FUNCTION_ARG_PADDING (@var{mode}, @var{type})
+If defined, a C expression which determines whether, and in which direction,
+to pad out an argument with extra space.  The value should be of type
+@code{enum direction}: either @code{upward} to pad above the argument,
+@code{downward} to pad below, or @code{none} to inhibit padding.
+
+The @emph{amount} of padding is always just enough to reach the next
+multiple of @code{FUNCTION_ARG_BOUNDARY}; this macro does not control
+it.
+
+This macro has a default definition which is right for most systems.
+For little-endian machines, the default is to pad upward.  For
+big-endian machines, the default is to pad downward for an argument of
+constant size shorter than an @code{int}, and upward otherwise.
+
+@findex PAD_VARARGS_DOWN
+@item PAD_VARARGS_DOWN
+If defined, a C expression which determines whether the default
+implementation of va_arg will attempt to pad down before reading the
+next argument, if that argument is smaller than its aligned space as
+controlled by @code{PARM_BOUNDARY}.  If this macro is not defined, all such
+arguments are padded down if @code{BYTES_BIG_ENDIAN} is true.
+
+@findex FUNCTION_ARG_BOUNDARY
+@item FUNCTION_ARG_BOUNDARY (@var{mode}, @var{type})
+If defined, a C expression that gives the alignment boundary, in bits,
+of an argument with the specified mode and type.  If it is not defined,
+@code{PARM_BOUNDARY} is used for all arguments.
+
+@findex FUNCTION_ARG_REGNO_P
+@item FUNCTION_ARG_REGNO_P (@var{regno})
+A C expression that is nonzero if @var{regno} is the number of a hard
+register in which function arguments are sometimes passed.  This does
+@emph{not} include implicit arguments such as the static chain and
+the structure-value address.  On many machines, no registers can be
+used for this purpose since all function arguments are pushed on the
+stack.
+
+@findex LOAD_ARGS_REVERSED
+@item LOAD_ARGS_REVERSED
+If defined, the order in which arguments are loaded into their
+respective argument registers is reversed so that the last
+argument is loaded first.  This macro only affects arguments
+passed in registers.
+
+@end table
+
+@node Scalar Return
+@subsection How Scalar Function Values Are Returned
+@cindex return values in registers
+@cindex values, returned by functions
+@cindex scalars, returned as values
+
+This section discusses the macros that control returning scalars as
+values---values that can fit in registers.
+
+@table @code
+@findex TRADITIONAL_RETURN_FLOAT
+@item TRADITIONAL_RETURN_FLOAT
+Define this macro if @option{-traditional} should not cause functions
+declared to return @code{float} to convert the value to @code{double}.
+
+@findex FUNCTION_VALUE
+@item FUNCTION_VALUE (@var{valtype}, @var{func})
+A C expression to create an RTX representing the place where a
+function returns a value of data type @var{valtype}.  @var{valtype} is
+a tree node representing a data type.  Write @code{TYPE_MODE
+(@var{valtype})} to get the machine mode used to represent that type.
+On many machines, only the mode is relevant.  (Actually, on most
+machines, scalar values are returned in the same place regardless of
+mode).
+
+The value of the expression is usually a @code{reg} RTX for the hard
+register where the return value is stored.  The value can also be a
+@code{parallel} RTX, if the return value is in multiple places.  See
+@code{FUNCTION_ARG} for an explanation of the @code{parallel} form.
+
+If @code{PROMOTE_FUNCTION_RETURN} is defined, you must apply the same
+promotion rules specified in @code{PROMOTE_MODE} if @var{valtype} is a
+scalar type.
+
+If the precise function being called is known, @var{func} is a tree
+node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null
+pointer.  This makes it possible to use a different value-returning
+convention for specific functions when all their calls are
+known.
+
+@code{FUNCTION_VALUE} is not used for return vales with aggregate data
+types, because these are returned in another way.  See
+@code{STRUCT_VALUE_REGNUM} and related macros, below.
+
+@findex FUNCTION_OUTGOING_VALUE
+@item FUNCTION_OUTGOING_VALUE (@var{valtype}, @var{func})
+Define this macro if the target machine has ``register windows''
+so that the register in which a function returns its value is not
+the same as the one in which the caller sees the value.
+
+For such machines, @code{FUNCTION_VALUE} computes the register in which
+the caller will see the value.  @code{FUNCTION_OUTGOING_VALUE} should be
+defined in a similar fashion to tell the function where to put the
+value.
+
+If @code{FUNCTION_OUTGOING_VALUE} is not defined,
+@code{FUNCTION_VALUE} serves both purposes.
+
+@code{FUNCTION_OUTGOING_VALUE} is not used for return vales with
+aggregate data types, because these are returned in another way.  See
+@code{STRUCT_VALUE_REGNUM} and related macros, below.
+
+@findex LIBCALL_VALUE
+@item LIBCALL_VALUE (@var{mode})
+A C expression to create an RTX representing the place where a library
+function returns a value of mode @var{mode}.  If the precise function
+being called is known, @var{func} is a tree node
+(@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null
+pointer.  This makes it possible to use a different value-returning
+convention for specific functions when all their calls are
+known.
+
+Note that ``library function'' in this context means a compiler
+support routine, used to perform arithmetic, whose name is known
+specially by the compiler and was not mentioned in the C code being
+compiled.
+
+The definition of @code{LIBRARY_VALUE} need not be concerned aggregate
+data types, because none of the library functions returns such types.
+
+@findex FUNCTION_VALUE_REGNO_P
+@item FUNCTION_VALUE_REGNO_P (@var{regno})
+A C expression that is nonzero if @var{regno} is the number of a hard
+register in which the values of called function may come back.
+
+A register whose use for returning values is limited to serving as the
+second of a pair (for a value of type @code{double}, say) need not be
+recognized by this macro.  So for most machines, this definition
+suffices:
+
+@example
+#define FUNCTION_VALUE_REGNO_P(N) ((N) == 0)
+@end example
+
+If the machine has register windows, so that the caller and the called
+function use different registers for the return value, this macro
+should recognize only the caller's register numbers.
+
+@findex APPLY_RESULT_SIZE
+@item APPLY_RESULT_SIZE
+Define this macro if @samp{untyped_call} and @samp{untyped_return}
+need more space than is implied by @code{FUNCTION_VALUE_REGNO_P} for
+saving and restoring an arbitrary return value.
+@end table
+
+@node Aggregate Return
+@subsection How Large Values Are Returned
+@cindex aggregates as return values
+@cindex large return values
+@cindex returning aggregate values
+@cindex structure value address
+
+When a function value's mode is @code{BLKmode} (and in some other
+cases), the value is not returned according to @code{FUNCTION_VALUE}
+(@pxref{Scalar Return}).  Instead, the caller passes the address of a
+block of memory in which the value should be stored.  This address
+is called the @dfn{structure value address}.
+
+This section describes how to control returning structure values in
+memory.
+
+@table @code
+@findex RETURN_IN_MEMORY
+@item RETURN_IN_MEMORY (@var{type})
+A C expression which can inhibit the returning of certain function
+values in registers, based on the type of value.  A nonzero value says
+to return the function value in memory, just as large structures are
+always returned.  Here @var{type} will be a C expression of type
+@code{tree}, representing the data type of the value.
+
+Note that values of mode @code{BLKmode} must be explicitly handled
+by this macro.  Also, the option @option{-fpcc-struct-return}
+takes effect regardless of this macro.  On most systems, it is
+possible to leave the macro undefined; this causes a default
+definition to be used, whose value is the constant 1 for @code{BLKmode}
+values, and 0 otherwise.
+
+Do not use this macro to indicate that structures and unions should always
+be returned in memory.  You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}
+to indicate this.
+
+@findex DEFAULT_PCC_STRUCT_RETURN
+@item DEFAULT_PCC_STRUCT_RETURN
+Define this macro to be 1 if all structure and union return values must be
+in memory.  Since this results in slower code, this should be defined
+only if needed for compatibility with other compilers or with an ABI@.
+If you define this macro to be 0, then the conventions used for structure
+and union return values are decided by the @code{RETURN_IN_MEMORY} macro.
+
+If not defined, this defaults to the value 1.
+
+@findex STRUCT_VALUE_REGNUM
+@item STRUCT_VALUE_REGNUM
+If the structure value address is passed in a register, then
+@code{STRUCT_VALUE_REGNUM} should be the number of that register.
+
+@findex STRUCT_VALUE
+@item STRUCT_VALUE
+If the structure value address is not passed in a register, define
+@code{STRUCT_VALUE} as an expression returning an RTX for the place
+where the address is passed.  If it returns 0, the address is passed as
+an ``invisible'' first argument.
+
+@findex STRUCT_VALUE_INCOMING_REGNUM
+@item STRUCT_VALUE_INCOMING_REGNUM
+On some architectures the place where the structure value address
+is found by the called function is not the same place that the
+caller put it.  This can be due to register windows, or it could
+be because the function prologue moves it to a different place.
+
+If the incoming location of the structure value address is in a
+register, define this macro as the register number.
+
+@findex STRUCT_VALUE_INCOMING
+@item STRUCT_VALUE_INCOMING
+If the incoming location is not a register, then you should define
+@code{STRUCT_VALUE_INCOMING} as an expression for an RTX for where the
+called function should find the value.  If it should find the value on
+the stack, define this to create a @code{mem} which refers to the frame
+pointer.  A definition of 0 means that the address is passed as an
+``invisible'' first argument.
+
+@findex PCC_STATIC_STRUCT_RETURN
+@item PCC_STATIC_STRUCT_RETURN
+Define this macro if the usual system convention on the target machine
+for returning structures and unions is for the called function to return
+the address of a static variable containing the value.
+
+Do not define this if the usual system convention is for the caller to
+pass an address to the subroutine.
+
+This macro has effect in @option{-fpcc-struct-return} mode, but it does
+nothing when you use @option{-freg-struct-return} mode.
+@end table
+
+@node Caller Saves
+@subsection Caller-Saves Register Allocation
+
+If you enable it, GCC can save registers around function calls.  This
+makes it possible to use call-clobbered registers to hold variables that
+must live across calls.
+
+@table @code
+@findex DEFAULT_CALLER_SAVES
+@item DEFAULT_CALLER_SAVES
+Define this macro if function calls on the target machine do not preserve
+any registers; in other words, if @code{CALL_USED_REGISTERS} has 1
+for all registers.  When defined, this macro enables @option{-fcaller-saves}
+by default for all optimization levels.  It has no effect for optimization
+levels 2 and higher, where @option{-fcaller-saves} is the default.
+
+@findex CALLER_SAVE_PROFITABLE
+@item CALLER_SAVE_PROFITABLE (@var{refs}, @var{calls})
+A C expression to determine whether it is worthwhile to consider placing
+a pseudo-register in a call-clobbered hard register and saving and
+restoring it around each function call.  The expression should be 1 when
+this is worth doing, and 0 otherwise.
+
+If you don't define this macro, a default is used which is good on most
+machines: @code{4 * @var{calls} < @var{refs}}.
+
+@findex HARD_REGNO_CALLER_SAVE_MODE
+@item HARD_REGNO_CALLER_SAVE_MODE (@var{regno}, @var{nregs})
+A C expression specifying which mode is required for saving @var{nregs}
+of a pseudo-register in call-clobbered hard register @var{regno}.  If
+@var{regno} is unsuitable for caller save, @code{VOIDmode} should be
+returned.  For most machines this macro need not be defined since GCC
+will select the smallest suitable mode.
+@end table
+
+@node Function Entry
+@subsection Function Entry and Exit
+@cindex function entry and exit
+@cindex prologue
+@cindex epilogue
+
+This section describes the macros that output function entry
+(@dfn{prologue}) and exit (@dfn{epilogue}) code.
+
+@deftypefn {Target Hook} void TARGET_ASM_FUNCTION_PROLOGUE (FILE *@var{file}, HOST_WIDE_INT @var{size})
+If defined, a function that outputs the assembler code for entry to a
+function.  The prologue is responsible for setting up the stack frame,
+initializing the frame pointer register, saving registers that must be
+saved, and allocating @var{size} additional bytes of storage for the
+local variables.  @var{size} is an integer.  @var{file} is a stdio
+stream to which the assembler code should be output.
+
+The label for the beginning of the function need not be output by this
+macro.  That has already been done when the macro is run.
+
+@findex regs_ever_live
+To determine which registers to save, the macro can refer to the array
+@code{regs_ever_live}: element @var{r} is nonzero if hard register
+@var{r} is used anywhere within the function.  This implies the function
+prologue should save register @var{r}, provided it is not one of the
+call-used registers.  (@code{TARGET_ASM_FUNCTION_EPILOGUE} must likewise use
+@code{regs_ever_live}.)
+
+On machines that have ``register windows'', the function entry code does
+not save on the stack the registers that are in the windows, even if
+they are supposed to be preserved by function calls; instead it takes
+appropriate steps to ``push'' the register stack, if any non-call-used
+registers are used in the function.
+
+@findex frame_pointer_needed
+On machines where functions may or may not have frame-pointers, the
+function entry code must vary accordingly; it must set up the frame
+pointer if one is wanted, and not otherwise.  To determine whether a
+frame pointer is in wanted, the macro can refer to the variable
+@code{frame_pointer_needed}.  The variable's value will be 1 at run
+time in a function that needs a frame pointer.  @xref{Elimination}.
+
+The function entry code is responsible for allocating any stack space
+required for the function.  This stack space consists of the regions
+listed below.  In most cases, these regions are allocated in the
+order listed, with the last listed region closest to the top of the
+stack (the lowest address if @code{STACK_GROWS_DOWNWARD} is defined, and
+the highest address if it is not defined).  You can use a different order
+for a machine if doing so is more convenient or required for
+compatibility reasons.  Except in cases where required by standard
+or by a debugger, there is no reason why the stack layout used by GCC
+need agree with that used by other compilers for a machine.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_ASM_FUNCTION_END_PROLOGUE (FILE *@var{file})
+If defined, a function that outputs assembler code at the end of a
+prologue.  This should be used when the function prologue is being
+emitted as RTL, and you have some extra assembler that needs to be
+emitted.  @xref{prologue instruction pattern}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_ASM_FUNCTION_BEGIN_EPILOGUE (FILE *@var{file})
+If defined, a function that outputs assembler code at the start of an
+epilogue.  This should be used when the function epilogue is being
+emitted as RTL, and you have some extra assembler that needs to be
+emitted.  @xref{epilogue instruction pattern}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_ASM_FUNCTION_EPILOGUE (FILE *@var{file}, HOST_WIDE_INT @var{size})
+If defined, a function that outputs the assembler code for exit from a
+function.  The epilogue is responsible for restoring the saved
+registers and stack pointer to their values when the function was
+called, and returning control to the caller.  This macro takes the
+same arguments as the macro @code{TARGET_ASM_FUNCTION_PROLOGUE}, and the
+registers to restore are determined from @code{regs_ever_live} and
+@code{CALL_USED_REGISTERS} in the same way.
+
+On some machines, there is a single instruction that does all the work
+of returning from the function.  On these machines, give that
+instruction the name @samp{return} and do not define the macro
+@code{TARGET_ASM_FUNCTION_EPILOGUE} at all.
+
+Do not define a pattern named @samp{return} if you want the
+@code{TARGET_ASM_FUNCTION_EPILOGUE} to be used.  If you want the target
+switches to control whether return instructions or epilogues are used,
+define a @samp{return} pattern with a validity condition that tests the
+target switches appropriately.  If the @samp{return} pattern's validity
+condition is false, epilogues will be used.
+
+On machines where functions may or may not have frame-pointers, the
+function exit code must vary accordingly.  Sometimes the code for these
+two cases is completely different.  To determine whether a frame pointer
+is wanted, the macro can refer to the variable
+@code{frame_pointer_needed}.  The variable's value will be 1 when compiling
+a function that needs a frame pointer.
+
+Normally, @code{TARGET_ASM_FUNCTION_PROLOGUE} and
+@code{TARGET_ASM_FUNCTION_EPILOGUE} must treat leaf functions specially.
+The C variable @code{current_function_is_leaf} is nonzero for such a
+function.  @xref{Leaf Functions}.
+
+On some machines, some functions pop their arguments on exit while
+others leave that for the caller to do.  For example, the 68020 when
+given @option{-mrtd} pops arguments in functions that take a fixed
+number of arguments.
+
+@findex current_function_pops_args
+Your definition of the macro @code{RETURN_POPS_ARGS} decides which
+functions pop their own arguments.  @code{TARGET_ASM_FUNCTION_EPILOGUE}
+needs to know what was decided.  The variable that is called
+@code{current_function_pops_args} is the number of bytes of its
+arguments that a function should pop.  @xref{Scalar Return}.
+@c what is the "its arguments" in the above sentence referring to, pray
+@c tell?  --mew 5feb93
+@end deftypefn
+
+@table @code
+
+@itemize @bullet
+@item
+@findex current_function_pretend_args_size
+A region of @code{current_function_pretend_args_size} bytes of
+uninitialized space just underneath the first argument arriving on the
+stack.  (This may not be at the very start of the allocated stack region
+if the calling sequence has pushed anything else since pushing the stack
+arguments.  But usually, on such machines, nothing else has been pushed
+yet, because the function prologue itself does all the pushing.)  This
+region is used on machines where an argument may be passed partly in
+registers and partly in memory, and, in some cases to support the
+features in @code{<varargs.h>} and @code{<stdarg.h>}.
+
+@item
+An area of memory used to save certain registers used by the function.
+The size of this area, which may also include space for such things as
+the return address and pointers to previous stack frames, is
+machine-specific and usually depends on which registers have been used
+in the function.  Machines with register windows often do not require
+a save area.
+
+@item
+A region of at least @var{size} bytes, possibly rounded up to an allocation
+boundary, to contain the local variables of the function.  On some machines,
+this region and the save area may occur in the opposite order, with the
+save area closer to the top of the stack.
+
+@item
+@cindex @code{ACCUMULATE_OUTGOING_ARGS} and stack frames
+Optionally, when @code{ACCUMULATE_OUTGOING_ARGS} is defined, a region of
+@code{current_function_outgoing_args_size} bytes to be used for outgoing
+argument lists of the function.  @xref{Stack Arguments}.
+@end itemize
+
+Normally, it is necessary for the macros
+@code{TARGET_ASM_FUNCTION_PROLOGUE} and
+@code{TARGET_ASM_FUNCTION_EPILOGUE} to treat leaf functions specially.
+The C variable @code{current_function_is_leaf} is nonzero for such a
+function.
+
+@findex EXIT_IGNORE_STACK
+@item EXIT_IGNORE_STACK
+Define this macro as a C expression that is nonzero if the return
+instruction or the function epilogue ignores the value of the stack
+pointer; in other words, if it is safe to delete an instruction to
+adjust the stack pointer before a return from the function.
+
+Note that this macro's value is relevant only for functions for which
+frame pointers are maintained.  It is never safe to delete a final
+stack adjustment in a function that has no frame pointer, and the
+compiler knows this regardless of @code{EXIT_IGNORE_STACK}.
+
+@findex EPILOGUE_USES
+@item EPILOGUE_USES (@var{regno})
+Define this macro as a C expression that is nonzero for registers that are
+used by the epilogue or the @samp{return} pattern.  The stack and frame
+pointer registers are already be assumed to be used as needed.
+
+@findex DELAY_SLOTS_FOR_EPILOGUE
+@item DELAY_SLOTS_FOR_EPILOGUE
+Define this macro if the function epilogue contains delay slots to which
+instructions from the rest of the function can be ``moved''.  The
+definition should be a C expression whose value is an integer
+representing the number of delay slots there.
+
+@findex ELIGIBLE_FOR_EPILOGUE_DELAY
+@item ELIGIBLE_FOR_EPILOGUE_DELAY (@var{insn}, @var{n})
+A C expression that returns 1 if @var{insn} can be placed in delay
+slot number @var{n} of the epilogue.
+
+The argument @var{n} is an integer which identifies the delay slot now
+being considered (since different slots may have different rules of
+eligibility).  It is never negative and is always less than the number
+of epilogue delay slots (what @code{DELAY_SLOTS_FOR_EPILOGUE} returns).
+If you reject a particular insn for a given delay slot, in principle, it
+may be reconsidered for a subsequent delay slot.  Also, other insns may
+(at least in principle) be considered for the so far unfilled delay
+slot.
+
+@findex current_function_epilogue_delay_list
+@findex final_scan_insn
+The insns accepted to fill the epilogue delay slots are put in an RTL
+list made with @code{insn_list} objects, stored in the variable
+@code{current_function_epilogue_delay_list}.  The insn for the first
+delay slot comes first in the list.  Your definition of the macro
+@code{TARGET_ASM_FUNCTION_EPILOGUE} should fill the delay slots by
+outputting the insns in this list, usually by calling
+@code{final_scan_insn}.
+
+You need not define this macro if you did not define
+@code{DELAY_SLOTS_FOR_EPILOGUE}.
+
+@findex ASM_OUTPUT_MI_THUNK
+@item ASM_OUTPUT_MI_THUNK (@var{file}, @var{thunk_fndecl}, @var{delta}, @var{function})
+A C compound statement that outputs the assembler code for a thunk
+function, used to implement C++ virtual function calls with multiple
+inheritance.  The thunk acts as a wrapper around a virtual function,
+adjusting the implicit object parameter before handing control off to
+the real function.
+
+First, emit code to add the integer @var{delta} to the location that
+contains the incoming first argument.  Assume that this argument
+contains a pointer, and is the one used to pass the @code{this} pointer
+in C++.  This is the incoming argument @emph{before} the function prologue,
+e.g.@: @samp{%o0} on a sparc.  The addition must preserve the values of
+all other incoming arguments.
+
+After the addition, emit code to jump to @var{function}, which is a
+@code{FUNCTION_DECL}.  This is a direct pure jump, not a call, and does
+not touch the return address.  Hence returning from @var{FUNCTION} will
+return to whoever called the current @samp{thunk}.
+
+The effect must be as if @var{function} had been called directly with
+the adjusted first argument.  This macro is responsible for emitting all
+of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}
+and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.
+
+The @var{thunk_fndecl} is redundant.  (@var{delta} and @var{function}
+have already been extracted from it.)  It might possibly be useful on
+some targets, but probably not.
+
+If you do not define this macro, the target-independent code in the C++
+front end will generate a less efficient heavyweight thunk that calls
+@var{function} instead of jumping to it.  The generic approach does
+not support varargs.
+@end table
+
+@node Profiling
+@subsection Generating Code for Profiling
+@cindex profiling, code generation
+
+These macros will help you generate code for profiling.
+
+@table @code
+@findex FUNCTION_PROFILER
+@item FUNCTION_PROFILER (@var{file}, @var{labelno})
+A C statement or compound statement to output to @var{file} some
+assembler code to call the profiling subroutine @code{mcount}.
+
+@findex mcount
+The details of how @code{mcount} expects to be called are determined by
+your operating system environment, not by GCC@.  To figure them out,
+compile a small program for profiling using the system's installed C
+compiler and look at the assembler code that results.
+
+Older implementations of @code{mcount} expect the address of a counter
+variable to be loaded into some register.  The name of this variable is
+@samp{LP} followed by the number @var{labelno}, so you would generate
+the name using @samp{LP%d} in a @code{fprintf}.
+
+@findex PROFILE_HOOK
+@item PROFILE_HOOK
+A C statement or compound statement to output to @var{file} some assembly
+code to call the profiling subroutine @code{mcount} even the target does
+not support profiling.
+
+@findex NO_PROFILE_COUNTERS
+@item NO_PROFILE_COUNTERS
+Define this macro if the @code{mcount} subroutine on your system does
+not need a counter variable allocated for each function.  This is true
+for almost all modern implementations.  If you define this macro, you
+must not use the @var{labelno} argument to @code{FUNCTION_PROFILER}.
+
+@findex PROFILE_BEFORE_PROLOGUE
+@item PROFILE_BEFORE_PROLOGUE
+Define this macro if the code for function profiling should come before
+the function prologue.  Normally, the profiling code comes after.
+
+
+@findex TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER
+@item TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER
+On some targets, it is impossible to use profiling when the frame
+pointer has been omitted.  For example, on x86 GNU/Linux systems,
+the @code{mcount} routine provided by the GNU C Library finds the
+address of the routine that called the routine that called @code{mcount}
+by looking in the immediate caller's stack frame.  If the immediate
+caller has no frame pointer, this lookup will fail.
+
+By default, GCC assumes that the target does allow profiling when the
+frame pointer is omitted.  This macro should be defined to a C
+expression that evaluates to @code{false} if the target does not allow
+profiling when the frame pointer is omitted.
+
+@end table
+
+@node Tail Calls
+@subsection Permitting tail calls
+@cindex tail calls
+
+@table @code
+@findex FUNCTION_OK_FOR_SIBCALL
+@item FUNCTION_OK_FOR_SIBCALL (@var{decl})
+A C expression that evaluates to true if it is ok to perform a sibling
+call to @var{decl} from the current function.
+
+It is not uncommon for limitations of calling conventions to prevent
+tail calls to functions outside the current unit of translation, or
+during PIC compilation.  Use this macro to enforce these restrictions,
+as the @code{sibcall} md pattern can not fail, or fall over to a
+``normal'' call.
+@end table
+
+@node Varargs
+@section Implementing the Varargs Macros
+@cindex varargs implementation
+
+GCC comes with an implementation of @code{<varargs.h>} and
+@code{<stdarg.h>} that work without change on machines that pass arguments
+on the stack.  Other machines require their own implementations of
+varargs, and the two machine independent header files must have
+conditionals to include it.
+
+ISO @code{<stdarg.h>} differs from traditional @code{<varargs.h>} mainly in
+the calling convention for @code{va_start}.  The traditional
+implementation takes just one argument, which is the variable in which
+to store the argument pointer.  The ISO implementation of
+@code{va_start} takes an additional second argument.  The user is
+supposed to write the last named argument of the function here.
+
+However, @code{va_start} should not use this argument.  The way to find
+the end of the named arguments is with the built-in functions described
+below.
+
+@table @code
+@findex __builtin_saveregs
+@item __builtin_saveregs ()
+Use this built-in function to save the argument registers in memory so
+that the varargs mechanism can access them.  Both ISO and traditional
+versions of @code{va_start} must use @code{__builtin_saveregs}, unless
+you use @code{SETUP_INCOMING_VARARGS} (see below) instead.
+
+On some machines, @code{__builtin_saveregs} is open-coded under the
+control of the macro @code{EXPAND_BUILTIN_SAVEREGS}.  On other machines,
+it calls a routine written in assembler language, found in
+@file{libgcc2.c}.
+
+Code generated for the call to @code{__builtin_saveregs} appears at the
+beginning of the function, as opposed to where the call to
+@code{__builtin_saveregs} is written, regardless of what the code is.
+This is because the registers must be saved before the function starts
+to use them for its own purposes.
+@c i rewrote the first sentence above to fix an overfull hbox. --mew
+@c 10feb93
+
+@findex __builtin_args_info
+@item __builtin_args_info (@var{category})
+Use this built-in function to find the first anonymous arguments in
+registers.
+
+In general, a machine may have several categories of registers used for
+arguments, each for a particular category of data types.  (For example,
+on some machines, floating-point registers are used for floating-point
+arguments while other arguments are passed in the general registers.)
+To make non-varargs functions use the proper calling convention, you
+have defined the @code{CUMULATIVE_ARGS} data type to record how many
+registers in each category have been used so far
+
+@code{__builtin_args_info} accesses the same data structure of type
+@code{CUMULATIVE_ARGS} after the ordinary argument layout is finished
+with it, with @var{category} specifying which word to access.  Thus, the
+value indicates the first unused register in a given category.
+
+Normally, you would use @code{__builtin_args_info} in the implementation
+of @code{va_start}, accessing each category just once and storing the
+value in the @code{va_list} object.  This is because @code{va_list} will
+have to update the values, and there is no way to alter the
+values accessed by @code{__builtin_args_info}.
+
+@findex __builtin_next_arg
+@item __builtin_next_arg (@var{lastarg})
+This is the equivalent of @code{__builtin_args_info}, for stack
+arguments.  It returns the address of the first anonymous stack
+argument, as type @code{void *}.  If @code{ARGS_GROW_DOWNWARD}, it
+returns the address of the location above the first anonymous stack
+argument.  Use it in @code{va_start} to initialize the pointer for
+fetching arguments from the stack.  Also use it in @code{va_start} to
+verify that the second parameter @var{lastarg} is the last named argument
+of the current function.
+
+@findex __builtin_classify_type
+@item __builtin_classify_type (@var{object})
+Since each machine has its own conventions for which data types are
+passed in which kind of register, your implementation of @code{va_arg}
+has to embody these conventions.  The easiest way to categorize the
+specified data type is to use @code{__builtin_classify_type} together
+with @code{sizeof} and @code{__alignof__}.
+
+@code{__builtin_classify_type} ignores the value of @var{object},
+considering only its data type.  It returns an integer describing what
+kind of type that is---integer, floating, pointer, structure, and so on.
+
+The file @file{typeclass.h} defines an enumeration that you can use to
+interpret the values of @code{__builtin_classify_type}.
+@end table
+
+These machine description macros help implement varargs:
+
+@table @code
+@findex EXPAND_BUILTIN_SAVEREGS
+@item EXPAND_BUILTIN_SAVEREGS ()
+If defined, is a C expression that produces the machine-specific code
+for a call to @code{__builtin_saveregs}.  This code will be moved to the
+very beginning of the function, before any parameter access are made.
+The return value of this function should be an RTX that contains the
+value to use as the return of @code{__builtin_saveregs}.
+
+@findex SETUP_INCOMING_VARARGS
+@item SETUP_INCOMING_VARARGS (@var{args_so_far}, @var{mode}, @var{type}, @var{pretend_args_size}, @var{second_time})
+This macro offers an alternative to using @code{__builtin_saveregs} and
+defining the macro @code{EXPAND_BUILTIN_SAVEREGS}.  Use it to store the
+anonymous register arguments into the stack so that all the arguments
+appear to have been passed consecutively on the stack.  Once this is
+done, you can use the standard implementation of varargs that works for
+machines that pass all their arguments on the stack.
+
+The argument @var{args_so_far} is the @code{CUMULATIVE_ARGS} data
+structure, containing the values that are obtained after processing the
+named arguments.  The arguments @var{mode} and @var{type} describe the
+last named argument---its machine mode and its data type as a tree node.
+
+The macro implementation should do two things: first, push onto the
+stack all the argument registers @emph{not} used for the named
+arguments, and second, store the size of the data thus pushed into the
+@code{int}-valued variable whose name is supplied as the argument
+@var{pretend_args_size}.  The value that you store here will serve as
+additional offset for setting up the stack frame.
+
+Because you must generate code to push the anonymous arguments at
+compile time without knowing their data types,
+@code{SETUP_INCOMING_VARARGS} is only useful on machines that have just
+a single category of argument register and use it uniformly for all data
+types.
+
+If the argument @var{second_time} is nonzero, it means that the
+arguments of the function are being analyzed for the second time.  This
+happens for an inline function, which is not actually compiled until the
+end of the source file.  The macro @code{SETUP_INCOMING_VARARGS} should
+not generate any instructions in this case.
+
+@findex STRICT_ARGUMENT_NAMING
+@item STRICT_ARGUMENT_NAMING
+Define this macro to be a nonzero value if the location where a function
+argument is passed depends on whether or not it is a named argument.
+
+This macro controls how the @var{named} argument to @code{FUNCTION_ARG}
+is set for varargs and stdarg functions.  If this macro returns a
+nonzero value, the @var{named} argument is always true for named
+arguments, and false for unnamed arguments.  If it returns a value of
+zero, but @code{SETUP_INCOMING_VARARGS} is defined, then all arguments
+are treated as named.  Otherwise, all named arguments except the last
+are treated as named.
+
+You need not define this macro if it always returns zero.
+
+@findex PRETEND_OUTGOING_VARARGS_NAMED
+@item PRETEND_OUTGOING_VARARGS_NAMED
+If you need to conditionally change ABIs so that one works with
+@code{SETUP_INCOMING_VARARGS}, but the other works like neither
+@code{SETUP_INCOMING_VARARGS} nor @code{STRICT_ARGUMENT_NAMING} was
+defined, then define this macro to return nonzero if
+@code{SETUP_INCOMING_VARARGS} is used, zero otherwise.
+Otherwise, you should not define this macro.
+@end table
+
+@node Trampolines
+@section Trampolines for Nested Functions
+@cindex trampolines for nested functions
+@cindex nested functions, trampolines for
+
+A @dfn{trampoline} is a small piece of code that is created at run time
+when the address of a nested function is taken.  It normally resides on
+the stack, in the stack frame of the containing function.  These macros
+tell GCC how to generate code to allocate and initialize a
+trampoline.
+
+The instructions in the trampoline must do two things: load a constant
+address into the static chain register, and jump to the real address of
+the nested function.  On CISC machines such as the m68k, this requires
+two instructions, a move immediate and a jump.  Then the two addresses
+exist in the trampoline as word-long immediate operands.  On RISC
+machines, it is often necessary to load each address into a register in
+two parts.  Then pieces of each address form separate immediate
+operands.
+
+The code generated to initialize the trampoline must store the variable
+parts---the static chain value and the function address---into the
+immediate operands of the instructions.  On a CISC machine, this is
+simply a matter of copying each address to a memory reference at the
+proper offset from the start of the trampoline.  On a RISC machine, it
+may be necessary to take out pieces of the address and store them
+separately.
+
+@table @code
+@findex TRAMPOLINE_TEMPLATE
+@item TRAMPOLINE_TEMPLATE (@var{file})
+A C statement to output, on the stream @var{file}, assembler code for a
+block of data that contains the constant parts of a trampoline.  This
+code should not include a label---the label is taken care of
+automatically.
+
+If you do not define this macro, it means no template is needed
+for the target.  Do not define this macro on systems where the block move
+code to copy the trampoline into place would be larger than the code
+to generate it on the spot.
+
+@findex TRAMPOLINE_SECTION
+@item TRAMPOLINE_SECTION
+The name of a subroutine to switch to the section in which the
+trampoline template is to be placed (@pxref{Sections}).  The default is
+a value of @samp{readonly_data_section}, which places the trampoline in
+the section containing read-only data.
+
+@findex TRAMPOLINE_SIZE
+@item TRAMPOLINE_SIZE
+A C expression for the size in bytes of the trampoline, as an integer.
+
+@findex TRAMPOLINE_ALIGNMENT
+@item TRAMPOLINE_ALIGNMENT
+Alignment required for trampolines, in bits.
+
+If you don't define this macro, the value of @code{BIGGEST_ALIGNMENT}
+is used for aligning trampolines.
+
+@findex INITIALIZE_TRAMPOLINE
+@item INITIALIZE_TRAMPOLINE (@var{addr}, @var{fnaddr}, @var{static_chain})
+A C statement to initialize the variable parts of a trampoline.
+@var{addr} is an RTX for the address of the trampoline; @var{fnaddr} is
+an RTX for the address of the nested function; @var{static_chain} is an
+RTX for the static chain value that should be passed to the function
+when it is called.
+
+@findex TRAMPOLINE_ADJUST_ADDRESS
+@item TRAMPOLINE_ADJUST_ADDRESS (@var{addr})
+A C statement that should perform any machine-specific adjustment in
+the address of the trampoline.  Its argument contains the address that
+was passed to @code{INITIALIZE_TRAMPOLINE}.  In case the address to be
+used for a function call should be different from the address in which
+the template was stored, the different address should be assigned to
+@var{addr}.  If this macro is not defined, @var{addr} will be used for
+function calls.
+
+@findex ALLOCATE_TRAMPOLINE
+@item ALLOCATE_TRAMPOLINE (@var{fp})
+A C expression to allocate run-time space for a trampoline.  The
+expression value should be an RTX representing a memory reference to the
+space for the trampoline.
+
+@cindex @code{TARGET_ASM_FUNCTION_EPILOGUE} and trampolines
+@cindex @code{TARGET_ASM_FUNCTION_PROLOGUE} and trampolines
+If this macro is not defined, by default the trampoline is allocated as
+a stack slot.  This default is right for most machines.  The exceptions
+are machines where it is impossible to execute instructions in the stack
+area.  On such machines, you may have to implement a separate stack,
+using this macro in conjunction with @code{TARGET_ASM_FUNCTION_PROLOGUE}
+and @code{TARGET_ASM_FUNCTION_EPILOGUE}.
+
+@var{fp} points to a data structure, a @code{struct function}, which
+describes the compilation status of the immediate containing function of
+the function which the trampoline is for.  Normally (when
+@code{ALLOCATE_TRAMPOLINE} is not defined), the stack slot for the
+trampoline is in the stack frame of this containing function.  Other
+allocation strategies probably must do something analogous with this
+information.
+@end table
+
+Implementing trampolines is difficult on many machines because they have
+separate instruction and data caches.  Writing into a stack location
+fails to clear the memory in the instruction cache, so when the program
+jumps to that location, it executes the old contents.
+
+Here are two possible solutions.  One is to clear the relevant parts of
+the instruction cache whenever a trampoline is set up.  The other is to
+make all trampolines identical, by having them jump to a standard
+subroutine.  The former technique makes trampoline execution faster; the
+latter makes initialization faster.
+
+To clear the instruction cache when a trampoline is initialized, define
+the following macros which describe the shape of the cache.
+
+@table @code
+@findex INSN_CACHE_SIZE
+@item INSN_CACHE_SIZE
+The total size in bytes of the cache.
+
+@findex INSN_CACHE_LINE_WIDTH
+@item INSN_CACHE_LINE_WIDTH
+The length in bytes of each cache line.  The cache is divided into cache
+lines which are disjoint slots, each holding a contiguous chunk of data
+fetched from memory.  Each time data is brought into the cache, an
+entire line is read at once.  The data loaded into a cache line is
+always aligned on a boundary equal to the line size.
+
+@findex INSN_CACHE_DEPTH
+@item INSN_CACHE_DEPTH
+The number of alternative cache lines that can hold any particular memory
+location.
+@end table
+
+Alternatively, if the machine has system calls or instructions to clear
+the instruction cache directly, you can define the following macro.
+
+@table @code
+@findex CLEAR_INSN_CACHE
+@item CLEAR_INSN_CACHE (@var{beg}, @var{end})
+If defined, expands to a C expression clearing the @emph{instruction
+cache} in the specified interval.  If it is not defined, and the macro
+@code{INSN_CACHE_SIZE} is defined, some generic code is generated to clear the
+cache.  The definition of this macro would typically be a series of
+@code{asm} statements.  Both @var{beg} and @var{end} are both pointer
+expressions.
+@end table
+
+To use a standard subroutine, define the following macro.  In addition,
+you must make sure that the instructions in a trampoline fill an entire
+cache line with identical instructions, or else ensure that the
+beginning of the trampoline code is always aligned at the same point in
+its cache line.  Look in @file{m68k.h} as a guide.
+
+@table @code
+@findex TRANSFER_FROM_TRAMPOLINE
+@item TRANSFER_FROM_TRAMPOLINE
+Define this macro if trampolines need a special subroutine to do their
+work.  The macro should expand to a series of @code{asm} statements
+which will be compiled with GCC@.  They go in a library function named
+@code{__transfer_from_trampoline}.
+
+If you need to avoid executing the ordinary prologue code of a compiled
+C function when you jump to the subroutine, you can do so by placing a
+special label of your own in the assembler code.  Use one @code{asm}
+statement to generate an assembler label, and another to make the label
+global.  Then trampolines can use that label to jump directly to your
+special assembler code.
+@end table
+
+@node Library Calls
+@section Implicit Calls to Library Routines
+@cindex library subroutine names
+@cindex @file{libgcc.a}
+
+@c prevent bad page break with this line
+Here is an explanation of implicit calls to library routines.
+
+@table @code
+@findex MULSI3_LIBCALL
+@item MULSI3_LIBCALL
+A C string constant giving the name of the function to call for
+multiplication of one signed full-word by another.  If you do not
+define this macro, the default name is used, which is @code{__mulsi3},
+a function defined in @file{libgcc.a}.
+
+@findex DIVSI3_LIBCALL
+@item DIVSI3_LIBCALL
+A C string constant giving the name of the function to call for
+division of one signed full-word by another.  If you do not define
+this macro, the default name is used, which is @code{__divsi3}, a
+function defined in @file{libgcc.a}.
+
+@findex UDIVSI3_LIBCALL
+@item UDIVSI3_LIBCALL
+A C string constant giving the name of the function to call for
+division of one unsigned full-word by another.  If you do not define
+this macro, the default name is used, which is @code{__udivsi3}, a
+function defined in @file{libgcc.a}.
+
+@findex MODSI3_LIBCALL
+@item MODSI3_LIBCALL
+A C string constant giving the name of the function to call for the
+remainder in division of one signed full-word by another.  If you do
+not define this macro, the default name is used, which is
+@code{__modsi3}, a function defined in @file{libgcc.a}.
+
+@findex UMODSI3_LIBCALL
+@item UMODSI3_LIBCALL
+A C string constant giving the name of the function to call for the
+remainder in division of one unsigned full-word by another.  If you do
+not define this macro, the default name is used, which is
+@code{__umodsi3}, a function defined in @file{libgcc.a}.
+
+@findex MULDI3_LIBCALL
+@item MULDI3_LIBCALL
+A C string constant giving the name of the function to call for
+multiplication of one signed double-word by another.  If you do not
+define this macro, the default name is used, which is @code{__muldi3},
+a function defined in @file{libgcc.a}.
+
+@findex DIVDI3_LIBCALL
+@item DIVDI3_LIBCALL
+A C string constant giving the name of the function to call for
+division of one signed double-word by another.  If you do not define
+this macro, the default name is used, which is @code{__divdi3}, a
+function defined in @file{libgcc.a}.
+
+@findex UDIVDI3_LIBCALL
+@item UDIVDI3_LIBCALL
+A C string constant giving the name of the function to call for
+division of one unsigned full-word by another.  If you do not define
+this macro, the default name is used, which is @code{__udivdi3}, a
+function defined in @file{libgcc.a}.
+
+@findex MODDI3_LIBCALL
+@item MODDI3_LIBCALL
+A C string constant giving the name of the function to call for the
+remainder in division of one signed double-word by another.  If you do
+not define this macro, the default name is used, which is
+@code{__moddi3}, a function defined in @file{libgcc.a}.
+
+@findex UMODDI3_LIBCALL
+@item UMODDI3_LIBCALL
+A C string constant giving the name of the function to call for the
+remainder in division of one unsigned full-word by another.  If you do
+not define this macro, the default name is used, which is
+@code{__umoddi3}, a function defined in @file{libgcc.a}.
+
+@findex INIT_TARGET_OPTABS
+@item INIT_TARGET_OPTABS
+Define this macro as a C statement that declares additional library
+routines renames existing ones.  @code{init_optabs} calls this macro after
+initializing all the normal library routines.
+
+@findex FLOAT_LIB_COMPARE_RETURNS_BOOL (@var{mode}, @var{comparison})
+@item FLOAT_LIB_COMPARE_RETURNS_BOOL
+Define this macro as a C statement that returns nonzero if a call to
+the floating point comparison library function will return a boolean
+value that indicates the result of the comparison.  It should return
+zero if one of gcc's own libgcc functions is called.
+
+Most ports don't need to define this macro.
+
+@findex TARGET_EDOM
+@cindex @code{EDOM}, implicit usage
+@item TARGET_EDOM
+The value of @code{EDOM} on the target machine, as a C integer constant
+expression.  If you don't define this macro, GCC does not attempt to
+deposit the value of @code{EDOM} into @code{errno} directly.  Look in
+@file{/usr/include/errno.h} to find the value of @code{EDOM} on your
+system.
+
+If you do not define @code{TARGET_EDOM}, then compiled code reports
+domain errors by calling the library function and letting it report the
+error.  If mathematical functions on your system use @code{matherr} when
+there is an error, then you should leave @code{TARGET_EDOM} undefined so
+that @code{matherr} is used normally.
+
+@findex GEN_ERRNO_RTX
+@cindex @code{errno}, implicit usage
+@item GEN_ERRNO_RTX
+Define this macro as a C expression to create an rtl expression that
+refers to the global ``variable'' @code{errno}.  (On certain systems,
+@code{errno} may not actually be a variable.)  If you don't define this
+macro, a reasonable default is used.
+
+@findex TARGET_MEM_FUNCTIONS
+@cindex @code{bcopy}, implicit usage
+@cindex @code{memcpy}, implicit usage
+@cindex @code{memmove}, implicit usage
+@cindex @code{bzero}, implicit usage
+@cindex @code{memset}, implicit usage
+@item TARGET_MEM_FUNCTIONS
+Define this macro if GCC should generate calls to the ISO C
+(and System V) library functions @code{memcpy}, @code{memmove} and
+@code{memset} rather than the BSD functions @code{bcopy} and @code{bzero}.
+
+@findex LIBGCC_NEEDS_DOUBLE
+@item LIBGCC_NEEDS_DOUBLE
+Define this macro if @code{float} arguments cannot be passed to library
+routines (so they must be converted to @code{double}).  This macro
+affects both how library calls are generated and how the library
+routines in @file{libgcc.a} accept their arguments.  It is useful on
+machines where floating and fixed point arguments are passed
+differently, such as the i860.
+
+@findex NEXT_OBJC_RUNTIME
+@item NEXT_OBJC_RUNTIME
+Define this macro to generate code for Objective-C message sending using
+the calling convention of the NeXT system.  This calling convention
+involves passing the object, the selector and the method arguments all
+at once to the method-lookup library function.
+
+The default calling convention passes just the object and the selector
+to the lookup function, which returns a pointer to the method.
+@end table
+
+@node Addressing Modes
+@section Addressing Modes
+@cindex addressing modes
+
+@c prevent bad page break with this line
+This is about addressing modes.
+
+@table @code
+@findex HAVE_PRE_INCREMENT
+@findex HAVE_PRE_DECREMENT
+@findex HAVE_POST_INCREMENT
+@findex HAVE_POST_DECREMENT
+@item HAVE_PRE_INCREMENT
+@itemx HAVE_PRE_DECREMENT
+@itemx HAVE_POST_INCREMENT
+@itemx HAVE_POST_DECREMENT
+A C expression that is nonzero if the machine supports pre-increment,
+pre-decrement, post-increment, or post-decrement addressing respectively.
+
+@findex HAVE_POST_MODIFY_DISP
+@findex HAVE_PRE_MODIFY_DISP
+@item HAVE_PRE_MODIFY_DISP
+@itemx HAVE_POST_MODIFY_DISP
+A C expression that is nonzero if the machine supports pre- or
+post-address side-effect generation involving constants other than
+the size of the memory operand.
+
+@findex HAVE_POST_MODIFY_REG
+@findex HAVE_PRE_MODIFY_REG
+@item HAVE_PRE_MODIFY_REG
+@itemx HAVE_POST_MODIFY_REG
+A C expression that is nonzero if the machine supports pre- or
+post-address side-effect generation involving a register displacement.
+
+@findex CONSTANT_ADDRESS_P
+@item CONSTANT_ADDRESS_P (@var{x})
+A C expression that is 1 if the RTX @var{x} is a constant which
+is a valid address.  On most machines, this can be defined as
+@code{CONSTANT_P (@var{x})}, but a few machines are more restrictive
+in which constant addresses are supported.
+
+@findex CONSTANT_P
+@code{CONSTANT_P} accepts integer-values expressions whose values are
+not explicitly known, such as @code{symbol_ref}, @code{label_ref}, and
+@code{high} expressions and @code{const} arithmetic expressions, in
+addition to @code{const_int} and @code{const_double} expressions.
+
+@findex MAX_REGS_PER_ADDRESS
+@item MAX_REGS_PER_ADDRESS
+A number, the maximum number of registers that can appear in a valid
+memory address.  Note that it is up to you to specify a value equal to
+the maximum number that @code{GO_IF_LEGITIMATE_ADDRESS} would ever
+accept.
+
+@findex GO_IF_LEGITIMATE_ADDRESS
+@item GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})
+A C compound statement with a conditional @code{goto @var{label};}
+executed if @var{x} (an RTX) is a legitimate memory address on the
+target machine for a memory operand of mode @var{mode}.
+
+It usually pays to define several simpler macros to serve as
+subroutines for this one.  Otherwise it may be too complicated to
+understand.
+
+This macro must exist in two variants: a strict variant and a
+non-strict one.  The strict variant is used in the reload pass.  It
+must be defined so that any pseudo-register that has not been
+allocated a hard register is considered a memory reference.  In
+contexts where some kind of register is required, a pseudo-register
+with no hard register must be rejected.
+
+The non-strict variant is used in other passes.  It must be defined to
+accept all pseudo-registers in every context where some kind of
+register is required.
+
+@findex REG_OK_STRICT
+Compiler source files that want to use the strict variant of this
+macro define the macro @code{REG_OK_STRICT}.  You should use an
+@code{#ifdef REG_OK_STRICT} conditional to define the strict variant
+in that case and the non-strict variant otherwise.
+
+Subroutines to check for acceptable registers for various purposes (one
+for base registers, one for index registers, and so on) are typically
+among the subroutines used to define @code{GO_IF_LEGITIMATE_ADDRESS}.
+Then only these subroutine macros need have two variants; the higher
+levels of macros may be the same whether strict or not.
+
+Normally, constant addresses which are the sum of a @code{symbol_ref}
+and an integer are stored inside a @code{const} RTX to mark them as
+constant.  Therefore, there is no need to recognize such sums
+specifically as legitimate addresses.  Normally you would simply
+recognize any @code{const} as legitimate.
+
+Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant
+sums that are not marked with  @code{const}.  It assumes that a naked
+@code{plus} indicates indexing.  If so, then you @emph{must} reject such
+naked constant sums as illegitimate addresses, so that none of them will
+be given to @code{PRINT_OPERAND_ADDRESS}.
+
+@cindex @code{ENCODE_SECTION_INFO} and address validation
+On some machines, whether a symbolic address is legitimate depends on
+the section that the address refers to.  On these machines, define the
+macro @code{ENCODE_SECTION_INFO} to store the information into the
+@code{symbol_ref}, and then check for it here.  When you see a
+@code{const}, you will have to look inside it to find the
+@code{symbol_ref} in order to determine the section.  @xref{Assembler
+Format}.
+
+@findex saveable_obstack
+The best way to modify the name string is by adding text to the
+beginning, with suitable punctuation to prevent any ambiguity.  Allocate
+the new name in @code{saveable_obstack}.  You will have to modify
+@code{ASM_OUTPUT_LABELREF} to remove and decode the added text and
+output the name accordingly, and define @code{STRIP_NAME_ENCODING} to
+access the original name string.
+
+You can check the information stored here into the @code{symbol_ref} in
+the definitions of the macros @code{GO_IF_LEGITIMATE_ADDRESS} and
+@code{PRINT_OPERAND_ADDRESS}.
+
+@findex REG_OK_FOR_BASE_P
+@item REG_OK_FOR_BASE_P (@var{x})
+A C expression that is nonzero if @var{x} (assumed to be a @code{reg}
+RTX) is valid for use as a base register.  For hard registers, it
+should always accept those which the hardware permits and reject the
+others.  Whether the macro accepts or rejects pseudo registers must be
+controlled by @code{REG_OK_STRICT} as described above.  This usually
+requires two variant definitions, of which @code{REG_OK_STRICT}
+controls the one actually used.
+
+@findex REG_MODE_OK_FOR_BASE_P
+@item REG_MODE_OK_FOR_BASE_P (@var{x}, @var{mode})
+A C expression that is just like @code{REG_OK_FOR_BASE_P}, except that
+that expression may examine the mode of the memory reference in
+@var{mode}.  You should define this macro if the mode of the memory
+reference affects whether a register may be used as a base register.  If
+you define this macro, the compiler will use it instead of
+@code{REG_OK_FOR_BASE_P}.
+
+@findex REG_OK_FOR_INDEX_P
+@item REG_OK_FOR_INDEX_P (@var{x})
+A C expression that is nonzero if @var{x} (assumed to be a @code{reg}
+RTX) is valid for use as an index register.
+
+The difference between an index register and a base register is that
+the index register may be scaled.  If an address involves the sum of
+two registers, neither one of them scaled, then either one may be
+labeled the ``base'' and the other the ``index''; but whichever
+labeling is used must fit the machine's constraints of which registers
+may serve in each capacity.  The compiler will try both labelings,
+looking for one that is valid, and will reload one or both registers
+only if neither labeling works.
+
+@findex FIND_BASE_TERM
+@item FIND_BASE_TERM (@var{x})
+A C expression to determine the base term of address @var{x}.
+This macro is used in only one place: `find_base_term' in alias.c.
+
+It is always safe for this macro to not be defined.  It exists so
+that alias analysis can understand machine-dependent addresses.
+
+The typical use of this macro is to handle addresses containing
+a label_ref or symbol_ref within an UNSPEC@.
+
+@findex LEGITIMIZE_ADDRESS
+@item LEGITIMIZE_ADDRESS (@var{x}, @var{oldx}, @var{mode}, @var{win})
+A C compound statement that attempts to replace @var{x} with a valid
+memory address for an operand of mode @var{mode}.  @var{win} will be a
+C statement label elsewhere in the code; the macro definition may use
+
+@example
+GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{win});
+@end example
+
+@noindent
+to avoid further processing if the address has become legitimate.
+
+@findex break_out_memory_refs
+@var{x} will always be the result of a call to @code{break_out_memory_refs},
+and @var{oldx} will be the operand that was given to that function to produce
+@var{x}.
+
+The code generated by this macro should not alter the substructure of
+@var{x}.  If it transforms @var{x} into a more legitimate form, it
+should assign @var{x} (which will always be a C variable) a new value.
+
+It is not necessary for this macro to come up with a legitimate
+address.  The compiler has standard ways of doing so in all cases.  In
+fact, it is safe for this macro to do nothing.  But often a
+machine-dependent strategy can generate better code.
+
+@findex LEGITIMIZE_RELOAD_ADDRESS
+@item LEGITIMIZE_RELOAD_ADDRESS (@var{x}, @var{mode}, @var{opnum}, @var{type}, @var{ind_levels}, @var{win})
+A C compound statement that attempts to replace @var{x}, which is an address
+that needs reloading, with a valid memory address for an operand of mode
+@var{mode}.  @var{win} will be a C statement label elsewhere in the code.
+It is not necessary to define this macro, but it might be useful for
+performance reasons.
+
+For example, on the i386, it is sometimes possible to use a single
+reload register instead of two by reloading a sum of two pseudo
+registers into a register.  On the other hand, for number of RISC
+processors offsets are limited so that often an intermediate address
+needs to be generated in order to address a stack slot.  By defining
+@code{LEGITIMIZE_RELOAD_ADDRESS} appropriately, the intermediate addresses
+generated for adjacent some stack slots can be made identical, and thus
+be shared.
+
+@emph{Note}: This macro should be used with caution.  It is necessary
+to know something of how reload works in order to effectively use this,
+and it is quite easy to produce macros that build in too much knowledge
+of reload internals.
+
+@emph{Note}: This macro must be able to reload an address created by a
+previous invocation of this macro.  If it fails to handle such addresses
+then the compiler may generate incorrect code or abort.
+
+@findex push_reload
+The macro definition should use @code{push_reload} to indicate parts that
+need reloading; @var{opnum}, @var{type} and @var{ind_levels} are usually
+suitable to be passed unaltered to @code{push_reload}.
+
+The code generated by this macro must not alter the substructure of
+@var{x}.  If it transforms @var{x} into a more legitimate form, it
+should assign @var{x} (which will always be a C variable) a new value.
+This also applies to parts that you change indirectly by calling
+@code{push_reload}.
+
+@findex strict_memory_address_p
+The macro definition may use @code{strict_memory_address_p} to test if
+the address has become legitimate.
+
+@findex copy_rtx
+If you want to change only a part of @var{x}, one standard way of doing
+this is to use @code{copy_rtx}.  Note, however, that is unshares only a
+single level of rtl.  Thus, if the part to be changed is not at the
+top level, you'll need to replace first the top level.
+It is not necessary for this macro to come up with a legitimate
+address;  but often a machine-dependent strategy can generate better code.
+
+@findex GO_IF_MODE_DEPENDENT_ADDRESS
+@item GO_IF_MODE_DEPENDENT_ADDRESS (@var{addr}, @var{label})
+A C statement or compound statement with a conditional @code{goto
+@var{label};} executed if memory address @var{x} (an RTX) can have
+different meanings depending on the machine mode of the memory
+reference it is used for or if the address is valid for some modes
+but not others.
+
+Autoincrement and autodecrement addresses typically have mode-dependent
+effects because the amount of the increment or decrement is the size
+of the operand being addressed.  Some machines have other mode-dependent
+addresses.  Many RISC machines have no mode-dependent addresses.
+
+You may assume that @var{addr} is a valid address for the machine.
+
+@findex LEGITIMATE_CONSTANT_P
+@item LEGITIMATE_CONSTANT_P (@var{x})
+A C expression that is nonzero if @var{x} is a legitimate constant for
+an immediate operand on the target machine.  You can assume that
+@var{x} satisfies @code{CONSTANT_P}, so you need not check this.  In fact,
+@samp{1} is a suitable definition for this macro on machines where
+anything @code{CONSTANT_P} is valid.
+@end table
+
+@node Condition Code
+@section Condition Code Status
+@cindex condition code status
+
+@c prevent bad page break with this line
+This describes the condition code status.
+
+@findex cc_status
+The file @file{conditions.h} defines a variable @code{cc_status} to
+describe how the condition code was computed (in case the interpretation of
+the condition code depends on the instruction that it was set by).  This
+variable contains the RTL expressions on which the condition code is
+currently based, and several standard flags.
+
+Sometimes additional machine-specific flags must be defined in the machine
+description header file.  It can also add additional machine-specific
+information by defining @code{CC_STATUS_MDEP}.
+
+@table @code
+@findex CC_STATUS_MDEP
+@item CC_STATUS_MDEP
+C code for a data type which is used for declaring the @code{mdep}
+component of @code{cc_status}.  It defaults to @code{int}.
+
+This macro is not used on machines that do not use @code{cc0}.
+
+@findex CC_STATUS_MDEP_INIT
+@item CC_STATUS_MDEP_INIT
+A C expression to initialize the @code{mdep} field to ``empty''.
+The default definition does nothing, since most machines don't use
+the field anyway.  If you want to use the field, you should probably
+define this macro to initialize it.
+
+This macro is not used on machines that do not use @code{cc0}.
+
+@findex NOTICE_UPDATE_CC
+@item NOTICE_UPDATE_CC (@var{exp}, @var{insn})
+A C compound statement to set the components of @code{cc_status}
+appropriately for an insn @var{insn} whose body is @var{exp}.  It is
+this macro's responsibility to recognize insns that set the condition
+code as a byproduct of other activity as well as those that explicitly
+set @code{(cc0)}.
+
+This macro is not used on machines that do not use @code{cc0}.
+
+If there are insns that do not set the condition code but do alter
+other machine registers, this macro must check to see whether they
+invalidate the expressions that the condition code is recorded as
+reflecting.  For example, on the 68000, insns that store in address
+registers do not set the condition code, which means that usually
+@code{NOTICE_UPDATE_CC} can leave @code{cc_status} unaltered for such
+insns.  But suppose that the previous insn set the condition code
+based on location @samp{a4@@(102)} and the current insn stores a new
+value in @samp{a4}.  Although the condition code is not changed by
+this, it will no longer be true that it reflects the contents of
+@samp{a4@@(102)}.  Therefore, @code{NOTICE_UPDATE_CC} must alter
+@code{cc_status} in this case to say that nothing is known about the
+condition code value.
+
+The definition of @code{NOTICE_UPDATE_CC} must be prepared to deal
+with the results of peephole optimization: insns whose patterns are
+@code{parallel} RTXs containing various @code{reg}, @code{mem} or
+constants which are just the operands.  The RTL structure of these
+insns is not sufficient to indicate what the insns actually do.  What
+@code{NOTICE_UPDATE_CC} should do when it sees one is just to run
+@code{CC_STATUS_INIT}.
+
+A possible definition of @code{NOTICE_UPDATE_CC} is to call a function
+that looks at an attribute (@pxref{Insn Attributes}) named, for example,
+@samp{cc}.  This avoids having detailed information about patterns in
+two places, the @file{md} file and in @code{NOTICE_UPDATE_CC}.
+
+@findex EXTRA_CC_MODES
+@item EXTRA_CC_MODES
+A list of additional modes for condition code values in registers
+(@pxref{Jump Patterns}).  This macro should expand to a sequence of
+calls of the macro @code{CC} separated by white space.  @code{CC} takes
+two arguments.  The first is the enumeration name of the mode, which
+should begin with @samp{CC} and end with @samp{mode}.  The second is a C
+string giving the printable name of the mode; it should be the same as
+the first argument, but with the trailing @samp{mode} removed.
+
+You should only define this macro if additional modes are required.
+
+A sample definition of @code{EXTRA_CC_MODES} is:
+@smallexample
+#define EXTRA_CC_MODES            \
+    CC(CC_NOOVmode, "CC_NOOV")    \
+    CC(CCFPmode, "CCFP")          \
+    CC(CCFPEmode, "CCFPE")
+@end smallexample
+
+@findex SELECT_CC_MODE
+@item SELECT_CC_MODE (@var{op}, @var{x}, @var{y})
+Returns a mode from class @code{MODE_CC} to be used when comparison
+operation code @var{op} is applied to rtx @var{x} and @var{y}.  For
+example, on the Sparc, @code{SELECT_CC_MODE} is defined as (see
+@pxref{Jump Patterns} for a description of the reason for this
+definition)
+
+@smallexample
+#define SELECT_CC_MODE(OP,X,Y) \
+  (GET_MODE_CLASS (GET_MODE (X)) == MODE_FLOAT          \
+   ? ((OP == EQ || OP == NE) ? CCFPmode : CCFPEmode)    \
+   : ((GET_CODE (X) == PLUS || GET_CODE (X) == MINUS    \
+       || GET_CODE (X) == NEG) \
+      ? CC_NOOVmode : CCmode))
+@end smallexample
+
+You need not define this macro if @code{EXTRA_CC_MODES} is not defined.
+
+@findex CANONICALIZE_COMPARISON
+@item CANONICALIZE_COMPARISON (@var{code}, @var{op0}, @var{op1})
+On some machines not all possible comparisons are defined, but you can
+convert an invalid comparison into a valid one.  For example, the Alpha
+does not have a @code{GT} comparison, but you can use an @code{LT}
+comparison instead and swap the order of the operands.
+
+On such machines, define this macro to be a C statement to do any
+required conversions.  @var{code} is the initial comparison code
+and @var{op0} and @var{op1} are the left and right operands of the
+comparison, respectively.  You should modify @var{code}, @var{op0}, and
+@var{op1} as required.
+
+GCC will not assume that the comparison resulting from this macro is
+valid but will see if the resulting insn matches a pattern in the
+@file{md} file.
+
+You need not define this macro if it would never change the comparison
+code or operands.
+
+@findex REVERSIBLE_CC_MODE
+@item REVERSIBLE_CC_MODE (@var{mode})
+A C expression whose value is one if it is always safe to reverse a
+comparison whose mode is @var{mode}.  If @code{SELECT_CC_MODE}
+can ever return @var{mode} for a floating-point inequality comparison,
+then @code{REVERSIBLE_CC_MODE (@var{mode})} must be zero.
+
+You need not define this macro if it would always returns zero or if the
+floating-point format is anything other than @code{IEEE_FLOAT_FORMAT}.
+For example, here is the definition used on the Sparc, where floating-point
+inequality comparisons are always given @code{CCFPEmode}:
+
+@smallexample
+#define REVERSIBLE_CC_MODE(MODE)  ((MODE) != CCFPEmode)
+@end smallexample
+
+@findex REVERSE_CONDITION (@var{code}, @var{mode})
+A C expression whose value is reversed condition code of the @var{code} for
+comparison done in CC_MODE @var{mode}.  The macro is used only in case
+@code{REVERSIBLE_CC_MODE (@var{mode})} is nonzero.  Define this macro in case
+machine has some non-standard way how to reverse certain conditionals.  For
+instance in case all floating point conditions are non-trapping, compiler may
+freely convert unordered compares to ordered one.  Then definition may look
+like:
+
+@smallexample
+#define REVERSE_CONDITION(CODE, MODE) \
+   ((MODE) != CCFPmode ? reverse_condition (CODE) \
+    : reverse_condition_maybe_unordered (CODE))
+@end smallexample
+
+@findex REVERSE_CONDEXEC_PREDICATES_P
+@item REVERSE_CONDEXEC_PREDICATES_P (@var{code1}, @var{code2})
+A C expression that returns true if the conditional execution predicate
+@var{code1} is the inverse of @var{code2} and vice versa.  Define this to
+return 0 if the target has conditional execution predicates that cannot be
+reversed safely.  If no expansion is specified, this macro is defined as
+follows:
+
+@smallexample
+#define REVERSE_CONDEXEC_PREDICATES_P (x, y) \
+   ((x) == reverse_condition (y))
+@end smallexample
+
+@end table
+
+@node Costs
+@section Describing Relative Costs of Operations
+@cindex costs of instructions
+@cindex relative costs
+@cindex speed of instructions
+
+These macros let you describe the relative speed of various operations
+on the target machine.
+
+@table @code
+@findex CONST_COSTS
+@item CONST_COSTS (@var{x}, @var{code}, @var{outer_code})
+A part of a C @code{switch} statement that describes the relative costs
+of constant RTL expressions.  It must contain @code{case} labels for
+expression codes @code{const_int}, @code{const}, @code{symbol_ref},
+@code{label_ref} and @code{const_double}.  Each case must ultimately
+reach a @code{return} statement to return the relative cost of the use
+of that kind of constant value in an expression.  The cost may depend on
+the precise value of the constant, which is available for examination in
+@var{x}, and the rtx code of the expression in which it is contained,
+found in @var{outer_code}.
+
+@var{code} is the expression code---redundant, since it can be
+obtained with @code{GET_CODE (@var{x})}.
+
+@findex RTX_COSTS
+@findex COSTS_N_INSNS
+@item RTX_COSTS (@var{x}, @var{code}, @var{outer_code})
+Like @code{CONST_COSTS} but applies to nonconstant RTL expressions.
+This can be used, for example, to indicate how costly a multiply
+instruction is.  In writing this macro, you can use the construct
+@code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast
+instructions.  @var{outer_code} is the code of the expression in which
+@var{x} is contained.
+
+This macro is optional; do not define it if the default cost assumptions
+are adequate for the target machine.
+
+@findex DEFAULT_RTX_COSTS
+@item DEFAULT_RTX_COSTS (@var{x}, @var{code}, @var{outer_code})
+This macro, if defined, is called for any case not handled by the
+@code{RTX_COSTS} or @code{CONST_COSTS} macros.  This eliminates the need
+to put case labels into the macro, but the code, or any functions it
+calls, must assume that the RTL in @var{x} could be of any type that has
+not already been handled.  The arguments are the same as for
+@code{RTX_COSTS}, and the macro should execute a return statement giving
+the cost of any RTL expressions that it can handle.  The default cost
+calculation is used for any RTL for which this macro does not return a
+value.
+
+This macro is optional; do not define it if the default cost assumptions
+are adequate for the target machine.
+
+@findex ADDRESS_COST
+@item ADDRESS_COST (@var{address})
+An expression giving the cost of an addressing mode that contains
+@var{address}.  If not defined, the cost is computed from
+the @var{address} expression and the @code{CONST_COSTS} values.
+
+For most CISC machines, the default cost is a good approximation of the
+true cost of the addressing mode.  However, on RISC machines, all
+instructions normally have the same length and execution time.  Hence
+all addresses will have equal costs.
+
+In cases where more than one form of an address is known, the form with
+the lowest cost will be used.  If multiple forms have the same, lowest,
+cost, the one that is the most complex will be used.
+
+For example, suppose an address that is equal to the sum of a register
+and a constant is used twice in the same basic block.  When this macro
+is not defined, the address will be computed in a register and memory
+references will be indirect through that register.  On machines where
+the cost of the addressing mode containing the sum is no higher than
+that of a simple indirect reference, this will produce an additional
+instruction and possibly require an additional register.  Proper
+specification of this macro eliminates this overhead for such machines.
+
+Similar use of this macro is made in strength reduction of loops.
+
+@var{address} need not be valid as an address.  In such a case, the cost
+is not relevant and can be any value; invalid addresses need not be
+assigned a different cost.
+
+On machines where an address involving more than one register is as
+cheap as an address computation involving only one register, defining
+@code{ADDRESS_COST} to reflect this can cause two registers to be live
+over a region of code where only one would have been if
+@code{ADDRESS_COST} were not defined in that manner.  This effect should
+be considered in the definition of this macro.  Equivalent costs should
+probably only be given to addresses with different numbers of registers
+on machines with lots of registers.
+
+This macro will normally either not be defined or be defined as a
+constant.
+
+@findex REGISTER_MOVE_COST
+@item REGISTER_MOVE_COST (@var{mode}, @var{from}, @var{to})
+A C expression for the cost of moving data of mode @var{mode} from a
+register in class @var{from} to one in class @var{to}.  The classes are
+expressed using the enumeration values such as @code{GENERAL_REGS}.  A
+value of 2 is the default; other values are interpreted relative to
+that.
+
+It is not required that the cost always equal 2 when @var{from} is the
+same as @var{to}; on some machines it is expensive to move between
+registers if they are not general registers.
+
+If reload sees an insn consisting of a single @code{set} between two
+hard registers, and if @code{REGISTER_MOVE_COST} applied to their
+classes returns a value of 2, reload does not check to ensure that the
+constraints of the insn are met.  Setting a cost of other than 2 will
+allow reload to verify that the constraints are met.  You should do this
+if the @samp{mov@var{m}} pattern's constraints do not allow such copying.
+
+@findex MEMORY_MOVE_COST
+@item MEMORY_MOVE_COST (@var{mode}, @var{class}, @var{in})
+A C expression for the cost of moving data of mode @var{mode} between a
+register of class @var{class} and memory; @var{in} is zero if the value
+is to be written to memory, nonzero if it is to be read in.  This cost
+is relative to those in @code{REGISTER_MOVE_COST}.  If moving between
+registers and memory is more expensive than between two registers, you
+should define this macro to express the relative cost.
+
+If you do not define this macro, GCC uses a default cost of 4 plus
+the cost of copying via a secondary reload register, if one is
+needed.  If your machine requires a secondary reload register to copy
+between memory and a register of @var{class} but the reload mechanism is
+more complex than copying via an intermediate, define this macro to
+reflect the actual cost of the move.
+
+GCC defines the function @code{memory_move_secondary_cost} if
+secondary reloads are needed.  It computes the costs due to copying via
+a secondary register.  If your machine copies from memory using a
+secondary register in the conventional way but the default base value of
+4 is not correct for your machine, define this macro to add some other
+value to the result of that function.  The arguments to that function
+are the same as to this macro.
+
+@findex BRANCH_COST
+@item BRANCH_COST
+A C expression for the cost of a branch instruction.  A value of 1 is
+the default; other values are interpreted relative to that.
+@end table
+
+Here are additional macros which do not specify precise relative costs,
+but only that certain actions are more expensive than GCC would
+ordinarily expect.
+
+@table @code
+@findex SLOW_BYTE_ACCESS
+@item SLOW_BYTE_ACCESS
+Define this macro as a C expression which is nonzero if accessing less
+than a word of memory (i.e.@: a @code{char} or a @code{short}) is no
+faster than accessing a word of memory, i.e., if such access
+require more than one instruction or if there is no difference in cost
+between byte and (aligned) word loads.
+
+When this macro is not defined, the compiler will access a field by
+finding the smallest containing object; when it is defined, a fullword
+load will be used if alignment permits.  Unless bytes accesses are
+faster than word accesses, using word accesses is preferable since it
+may eliminate subsequent memory access if subsequent accesses occur to
+other fields in the same word of the structure, but to different bytes.
+
+@findex SLOW_UNALIGNED_ACCESS
+@item SLOW_UNALIGNED_ACCESS (@var{mode}, @var{alignment})
+Define this macro to be the value 1 if memory accesses described by the
+@var{mode} and @var{alignment} parameters have a cost many times greater
+than aligned accesses, for example if they are emulated in a trap
+handler.
+
+When this macro is nonzero, the compiler will act as if
+@code{STRICT_ALIGNMENT} were nonzero when generating code for block
+moves.  This can cause significantly more instructions to be produced.
+Therefore, do not set this macro nonzero if unaligned accesses only add a
+cycle or two to the time for a memory access.
+
+If the value of this macro is always zero, it need not be defined.  If
+this macro is defined, it should produce a nonzero value when
+@code{STRICT_ALIGNMENT} is nonzero.
+
+@findex DONT_REDUCE_ADDR
+@item DONT_REDUCE_ADDR
+Define this macro to inhibit strength reduction of memory addresses.
+(On some machines, such strength reduction seems to do harm rather
+than good.)
+
+@findex MOVE_RATIO
+@item MOVE_RATIO
+The threshold of number of scalar memory-to-memory move insns, @emph{below}
+which a sequence of insns should be generated instead of a
+string move insn or a library call.  Increasing the value will always
+make code faster, but eventually incurs high cost in increased code size.
+
+Note that on machines where the corresponding move insn is a
+@code{define_expand} that emits a sequence of insns, this macro counts
+the number of such sequences.
+
+If you don't define this, a reasonable default is used.
+
+@findex MOVE_BY_PIECES_P
+@item MOVE_BY_PIECES_P (@var{size}, @var{alignment})
+A C expression used to determine whether @code{move_by_pieces} will be used to
+copy a chunk of memory, or whether some other block move mechanism
+will be used.  Defaults to 1 if @code{move_by_pieces_ninsns} returns less
+than @code{MOVE_RATIO}.
+
+@findex MOVE_MAX_PIECES
+@item MOVE_MAX_PIECES
+A C expression used by @code{move_by_pieces} to determine the largest unit
+a load or store used to copy memory is.  Defaults to @code{MOVE_MAX}.
+
+@findex USE_LOAD_POST_INCREMENT
+@item USE_LOAD_POST_INCREMENT (@var{mode})
+A C expression used to determine whether a load postincrement is a good
+thing to use for a given mode.  Defaults to the value of
+@code{HAVE_POST_INCREMENT}.
+
+@findex USE_LOAD_POST_DECREMENT
+@item USE_LOAD_POST_DECREMENT (@var{mode})
+A C expression used to determine whether a load postdecrement is a good
+thing to use for a given mode.  Defaults to the value of
+@code{HAVE_POST_DECREMENT}.
+
+@findex USE_LOAD_PRE_INCREMENT
+@item USE_LOAD_PRE_INCREMENT (@var{mode})
+A C expression used to determine whether a load preincrement is a good
+thing to use for a given mode.  Defaults to the value of
+@code{HAVE_PRE_INCREMENT}.
+
+@findex USE_LOAD_PRE_DECREMENT
+@item USE_LOAD_PRE_DECREMENT (@var{mode})
+A C expression used to determine whether a load predecrement is a good
+thing to use for a given mode.  Defaults to the value of
+@code{HAVE_PRE_DECREMENT}.
+
+@findex USE_STORE_POST_INCREMENT
+@item USE_STORE_POST_INCREMENT (@var{mode})
+A C expression used to determine whether a store postincrement is a good
+thing to use for a given mode.  Defaults to the value of
+@code{HAVE_POST_INCREMENT}.
+
+@findex USE_STORE_POST_DECREMENT
+@item USE_STORE_POST_DECREMENT (@var{mode})
+A C expression used to determine whether a store postdecrement is a good
+thing to use for a given mode.  Defaults to the value of
+@code{HAVE_POST_DECREMENT}.
+
+@findex USE_STORE_PRE_INCREMENT
+@item USE_STORE_PRE_INCREMENT (@var{mode})
+This macro is used to determine whether a store preincrement is a good
+thing to use for a given mode.  Defaults to the value of
+@code{HAVE_PRE_INCREMENT}.
+
+@findex USE_STORE_PRE_DECREMENT
+@item USE_STORE_PRE_DECREMENT (@var{mode})
+This macro is used to determine whether a store predecrement is a good
+thing to use for a given mode.  Defaults to the value of
+@code{HAVE_PRE_DECREMENT}.
+
+@findex NO_FUNCTION_CSE
+@item NO_FUNCTION_CSE
+Define this macro if it is as good or better to call a constant
+function address than to call an address kept in a register.
+
+@findex NO_RECURSIVE_FUNCTION_CSE
+@item NO_RECURSIVE_FUNCTION_CSE
+Define this macro if it is as good or better for a function to call
+itself with an explicit address than to call an address kept in a
+register.
+@end table
+
+@node Scheduling
+@section Adjusting the Instruction Scheduler
+
+The instruction scheduler may need a fair amount of machine-specific
+adjustment in order to produce good code.  GCC provides several target
+hooks for this purpose.  It is usually enough to define just a few of
+them: try the first ones in this list first.
+
+@deftypefn {Target Hook} int TARGET_SCHED_ISSUE_RATE (void)
+This hook returns the maximum number of instructions that can ever issue
+at the same time on the target machine.  The default is one.  This value
+must be constant over the entire compilation.  If you need it to vary
+depending on what the instructions are, you must use
+@samp{TARGET_SCHED_VARIABLE_ISSUE}.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_VARIABLE_ISSUE (FILE *@var{file}, int @var{verbose}, rtx @var{insn}, int @var{more})
+This hook is executed by the scheduler after it has scheduled an insn
+from the ready list.  It should return the number of insns which can
+still be issued in the current cycle.  Normally this is
+@samp{@w{@var{more} - 1}}.  You should define this hook if some insns
+take more machine resources than others, so that fewer insns can follow
+them in the same cycle.  @var{file} is either a null pointer, or a stdio
+stream to write any debug output to.  @var{verbose} is the verbose level
+provided by @option{-fsched-verbose-@var{n}}.  @var{insn} is the
+instruction that was scheduled.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_ADJUST_COST (rtx @var{insn}, rtx @var{link}, rtx @var{dep_insn}, int @var{cost})
+This function corrects the value of @var{cost} based on the relationship
+between @var{insn} and @var{dep_insn} through the dependence @var{link}.
+It should return the new value.  The default is to make no adjustment to
+@var{cost}.  This can be used for example to specify to the scheduler
+that an output- or anti-dependence does not incur the same cost as a
+data-dependence.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_ADJUST_PRIORITY (rtx @var{insn}, int @var{priority})
+This hook adjusts the integer scheduling priority @var{priority} of
+@var{insn}.  It should return the new priority.  Reduce the priority to
+execute @var{insn} earlier, increase the priority to execute @var{insn}
+later.  Do not define this hook if you do not need to adjust the
+scheduling priorities of insns.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_REORDER (FILE *@var{file}, int @var{verbose}, rtx *@var{ready}, int *@var{n_readyp}, int @var{clock})
+This hook is executed by the scheduler after it has scheduled the ready
+list, to allow the machine description to reorder it (for example to
+combine two small instructions together on @samp{VLIW} machines).
+@var{file} is either a null pointer, or a stdio stream to write any
+debug output to.  @var{verbose} is the verbose level provided by
+@option{-fsched-verbose-@var{n}}.  @var{ready} is a pointer to the ready
+list of instructions that are ready to be scheduled.  @var{n_readyp} is
+a pointer to the number of elements in the ready list.  The scheduler
+reads the ready list in reverse order, starting with
+@var{ready}[@var{*n_readyp}-1] and going to @var{ready}[0].  @var{clock}
+is the timer tick of the scheduler.  You may modify the ready list and
+the number of ready insns.  The return value is the number of insns that
+can issue this cycle; normally this is just @code{issue_rate}.  See also
+@samp{TARGET_SCHED_REORDER2}.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_REORDER2 (FILE *@var{file}, int @var{verbose}, rtx *@var{ready}, int *@var{n_ready}, @var{clock})
+Like @samp{TARGET_SCHED_REORDER}, but called at a different time.  That
+function is called whenever the scheduler starts a new cycle.  This one
+is called once per iteration over a cycle, immediately after
+@samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and
+return the number of insns to be scheduled in the same cycle.  Defining
+this hook can be useful if there are frequent situations where
+scheduling one insn causes other insns to become ready in the same
+cycle.  These other insns can then be taken into account properly.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_INIT (FILE *@var{file}, int @var{verbose}, int @var{max_ready})
+This hook is executed by the scheduler at the beginning of each block of
+instructions that are to be scheduled.  @var{file} is either a null
+pointer, or a stdio stream to write any debug output to.  @var{verbose}
+is the verbose level provided by @option{-fsched-verbose-@var{n}}.
+@var{max_ready} is the maximum number of insns in the current scheduling
+region that can be live at the same time.  This can be used to allocate
+scratch space if it is needed, e.g. by @samp{TARGET_SCHED_REORDER}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_FINISH (FILE *@var{file}, int @var{verbose})
+This hook is executed by the scheduler at the end of each block of
+instructions that are to be scheduled.  It can be used to perform
+cleanup of any actions done by the other scheduling hooks.  @var{file}
+is either a null pointer, or a stdio stream to write any debug output
+to.  @var{verbose} is the verbose level provided by
+@option{-fsched-verbose-@var{n}}.
+@end deftypefn
+
+@deftypefn {Target Hook} rtx TARGET_SCHED_CYCLE_DISPLAY (int @var{clock}, rtx @var{last})
+This hook is called in verbose mode only, at the beginning of each pass
+over a basic block.  It should insert an insn into the chain after
+@var{last}, which has no effect, but records the value @var{clock} in
+RTL dumps and assembly output.  Define this hook only if you need this
+level of detail about what the scheduler is doing.
+@end deftypefn
+
+@node Sections
+@section Dividing the Output into Sections (Texts, Data, @dots{})
+@c the above section title is WAY too long.  maybe cut the part between
+@c the (...)?  --mew 10feb93
+
+An object file is divided into sections containing different types of
+data.  In the most common case, there are three sections: the @dfn{text
+section}, which holds instructions and read-only data; the @dfn{data
+section}, which holds initialized writable data; and the @dfn{bss
+section}, which holds uninitialized data.  Some systems have other kinds
+of sections.
+
+The compiler must tell the assembler when to switch sections.  These
+macros control what commands to output to tell the assembler this.  You
+can also define additional sections.
+
+@table @code
+@findex TEXT_SECTION_ASM_OP
+@item TEXT_SECTION_ASM_OP
+A C expression whose value is a string, including spacing, containing the
+assembler operation that should precede instructions and read-only data.
+Normally @code{"\t.text"} is right.
+
+@findex TEXT_SECTION
+@item TEXT_SECTION
+A C statement that switches to the default section containing instructions.
+Normally this is not needed, as simply defining @code{TEXT_SECTION_ASM_OP}
+is enough.  The MIPS port uses this to sort all functions after all data
+declarations.
+
+@findex DATA_SECTION_ASM_OP
+@item DATA_SECTION_ASM_OP
+A C expression whose value is a string, including spacing, containing the
+assembler operation to identify the following data as writable initialized
+data.  Normally @code{"\t.data"} is right.
+
+@findex SHARED_SECTION_ASM_OP
+@item SHARED_SECTION_ASM_OP
+If defined, a C expression whose value is a string, including spacing,
+containing the assembler operation to identify the following data as
+shared data.  If not defined, @code{DATA_SECTION_ASM_OP} will be used.
+
+@findex BSS_SECTION_ASM_OP
+@item BSS_SECTION_ASM_OP
+If defined, a C expression whose value is a string, including spacing,
+containing the assembler operation to identify the following data as
+uninitialized global data.  If not defined, and neither
+@code{ASM_OUTPUT_BSS} nor @code{ASM_OUTPUT_ALIGNED_BSS} are defined,
+uninitialized global data will be output in the data section if
+@option{-fno-common} is passed, otherwise @code{ASM_OUTPUT_COMMON} will be
+used.
+
+@findex SHARED_BSS_SECTION_ASM_OP
+@item SHARED_BSS_SECTION_ASM_OP
+If defined, a C expression whose value is a string, including spacing,
+containing the assembler operation to identify the following data as
+uninitialized global shared data.  If not defined, and
+@code{BSS_SECTION_ASM_OP} is, the latter will be used.
+
+@findex INIT_SECTION_ASM_OP
+@item INIT_SECTION_ASM_OP
+If defined, a C expression whose value is a string, including spacing,
+containing the assembler operation to identify the following data as
+initialization code.  If not defined, GCC will assume such a section does
+not exist.
+
+@findex FINI_SECTION_ASM_OP
+@item FINI_SECTION_ASM_OP
+If defined, a C expression whose value is a string, including spacing,
+containing the assembler operation to identify the following data as
+finalization code.  If not defined, GCC will assume such a section does
+not exist.
+
+@findex CRT_CALL_STATIC_FUNCTION
+@item CRT_CALL_STATIC_FUNCTION (@var{section_op}, @var{function})
+If defined, an ASM statement that switches to a different section
+via @var{section_op}, calls @var{function}, and switches back to
+the text section.  This is used in @file{crtstuff.c} if
+@code{INIT_SECTION_ASM_OP} or @code{FINI_SECTION_ASM_OP} to calls
+to initialization and finalization functions from the init and fini
+sections.  By default, this macro uses a simple function call.  Some
+ports need hand-crafted assembly code to avoid dependencies on
+registers initialized in the function prologue or to ensure that
+constant pools don't end up too far way in the text section.
+
+@findex FORCE_CODE_SECTION_ALIGN
+@item FORCE_CODE_SECTION_ALIGN
+If defined, an ASM statement that aligns a code section to some
+arbitrary boundary.  This is used to force all fragments of the
+@code{.init} and @code{.fini} sections to have to same alignment
+and thus prevent the linker from having to add any padding.
+
+@findex EXTRA_SECTIONS
+@findex in_text
+@findex in_data
+@item EXTRA_SECTIONS
+A list of names for sections other than the standard two, which are
+@code{in_text} and @code{in_data}.  You need not define this macro
+on a system with no other sections (that GCC needs to use).
+
+@findex EXTRA_SECTION_FUNCTIONS
+@findex text_section
+@findex data_section
+@item EXTRA_SECTION_FUNCTIONS
+One or more functions to be defined in @file{varasm.c}.  These
+functions should do jobs analogous to those of @code{text_section} and
+@code{data_section}, for your additional sections.  Do not define this
+macro if you do not define @code{EXTRA_SECTIONS}.
+
+@findex READONLY_DATA_SECTION
+@item READONLY_DATA_SECTION
+On most machines, read-only variables, constants, and jump tables are
+placed in the text section.  If this is not the case on your machine,
+this macro should be defined to be the name of a function (either
+@code{data_section} or a function defined in @code{EXTRA_SECTIONS}) that
+switches to the section to be used for read-only items.
+
+If these items should be placed in the text section, this macro should
+not be defined.
+
+@findex SELECT_SECTION
+@item SELECT_SECTION (@var{exp}, @var{reloc}, @var{align})
+A C statement or statements to switch to the appropriate section for
+output of @var{exp}.  You can assume that @var{exp} is either a
+@code{VAR_DECL} node or a constant of some sort.  @var{reloc}
+indicates whether the initial value of @var{exp} requires link-time
+relocations.  Bit 1 is set when variable contains local relocations
+only, while bit 2 is set for global relocations.
+Select the section by calling @code{text_section} or one
+of the alternatives for other sections.  @var{align} is the constant
+alignment in bits.
+
+Do not define this macro if you put all read-only variables and
+constants in the read-only data section (usually the text section).
+
+@findex SELECT_RTX_SECTION
+@item SELECT_RTX_SECTION (@var{mode}, @var{rtx}, @var{align})
+A C statement or statements to switch to the appropriate section for
+output of @var{rtx} in mode @var{mode}.  You can assume that @var{rtx}
+is some kind of constant in RTL@.  The argument @var{mode} is redundant
+except in the case of a @code{const_int} rtx.  Select the section by
+calling @code{text_section} or one of the alternatives for other
+sections.  @var{align} is the constant alignment in bits.
+
+Do not define this macro if you put all constants in the read-only
+data section.
+
+@findex JUMP_TABLES_IN_TEXT_SECTION
+@item JUMP_TABLES_IN_TEXT_SECTION
+Define this macro to be an expression with a nonzero value if jump
+tables (for @code{tablejump} insns) should be output in the text
+section, along with the assembler instructions.  Otherwise, the
+readonly data section is used.
+
+This macro is irrelevant if there is no separate readonly data section.
+
+@findex ENCODE_SECTION_INFO
+@item ENCODE_SECTION_INFO (@var{decl})
+Define this macro if references to a symbol or a constant must be
+treated differently depending on something about the variable or
+function named by the symbol (such as what section it is in).
+
+The macro definition, if any, is executed under two circumstances.  One
+is immediately after the rtl for @var{decl} that represents a variable
+or a function has been created and stored in @code{DECL_RTL
+(@var{decl})}.  The value of the rtl will be a @code{mem} whose address
+is a @code{symbol_ref}.  The other is immediately after the rtl for
+@var{decl} that represents a constant has been created and stored in
+@code{TREE_CST_RTL (@var{decl})}.  The macro is called once for each
+distinct constant in a source file.
+
+@cindex @code{SYMBOL_REF_FLAG}, in @code{ENCODE_SECTION_INFO}
+The usual thing for this macro to do is to record a flag in the
+@code{symbol_ref} (such as @code{SYMBOL_REF_FLAG}) or to store a
+modified name string in the @code{symbol_ref} (if one bit is not enough
+information).
+
+@findex STRIP_NAME_ENCODING
+@item STRIP_NAME_ENCODING (@var{var}, @var{sym_name})
+Decode @var{sym_name} and store the real name part in @var{var}, sans
+the characters that encode section info.  Define this macro if
+@code{ENCODE_SECTION_INFO} alters the symbol's name string.
+
+@findex UNIQUE_SECTION
+@item UNIQUE_SECTION (@var{decl}, @var{reloc})
+A C statement to build up a unique section name, expressed as a
+@code{STRING_CST} node, and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.
+@var{reloc} indicates whether the initial value of @var{exp} requires
+link-time relocations.  If you do not define this macro, GCC will use
+the symbol name prefixed by @samp{.} as the section name.  Note - this
+macro can now be called for uninitialized data items as well as
+initialized data and functions.
+@end table
+
+@node PIC
+@section Position Independent Code
+@cindex position independent code
+@cindex PIC
+
+This section describes macros that help implement generation of position
+independent code.  Simply defining these macros is not enough to
+generate valid PIC; you must also add support to the macros
+@code{GO_IF_LEGITIMATE_ADDRESS} and @code{PRINT_OPERAND_ADDRESS}, as
+well as @code{LEGITIMIZE_ADDRESS}.  You must modify the definition of
+@samp{movsi} to do something appropriate when the source operand
+contains a symbolic address.  You may also need to alter the handling of
+switch statements so that they use relative addresses.
+@c i rearranged the order of the macros above to try to force one of
+@c them to the next line, to eliminate an overfull hbox. --mew 10feb93
+
+@table @code
+@findex PIC_OFFSET_TABLE_REGNUM
+@item PIC_OFFSET_TABLE_REGNUM
+The register number of the register used to address a table of static
+data addresses in memory.  In some cases this register is defined by a
+processor's ``application binary interface'' (ABI)@.  When this macro
+is defined, RTL is generated for this register once, as with the stack
+pointer and frame pointer registers.  If this macro is not defined, it
+is up to the machine-dependent files to allocate such a register (if
+necessary).  Note that this register must be fixed when in use (e.g.@:
+when @code{flag_pic} is true).
+
+@findex PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
+@item PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
+Define this macro if the register defined by
+@code{PIC_OFFSET_TABLE_REGNUM} is clobbered by calls.  Do not define
+this macro if @code{PIC_OFFSET_TABLE_REGNUM} is not defined.
+
+@findex FINALIZE_PIC
+@item FINALIZE_PIC
+By generating position-independent code, when two different programs (A
+and B) share a common library (libC.a), the text of the library can be
+shared whether or not the library is linked at the same address for both
+programs.  In some of these environments, position-independent code
+requires not only the use of different addressing modes, but also
+special code to enable the use of these addressing modes.
+
+The @code{FINALIZE_PIC} macro serves as a hook to emit these special
+codes once the function is being compiled into assembly code, but not
+before.  (It is not done before, because in the case of compiling an
+inline function, it would lead to multiple PIC prologues being
+included in functions which used inline functions and were compiled to
+assembly language.)
+
+@findex LEGITIMATE_PIC_OPERAND_P
+@item LEGITIMATE_PIC_OPERAND_P (@var{x})
+A C expression that is nonzero if @var{x} is a legitimate immediate
+operand on the target machine when generating position independent code.
+You can assume that @var{x} satisfies @code{CONSTANT_P}, so you need not
+check this.  You can also assume @var{flag_pic} is true, so you need not
+check it either.  You need not define this macro if all constants
+(including @code{SYMBOL_REF}) can be immediate operands when generating
+position independent code.
+@end table
+
+@node Assembler Format
+@section Defining the Output Assembler Language
+
+This section describes macros whose principal purpose is to describe how
+to write instructions in assembler language---rather than what the
+instructions do.
+
+@menu
+* File Framework::       Structural information for the assembler file.
+* Data Output::          Output of constants (numbers, strings, addresses).
+* Uninitialized Data::   Output of uninitialized variables.
+* Label Output::         Output and generation of labels.
+* Initialization::       General principles of initialization
+			   and termination routines.
+* Macros for Initialization::
+			 Specific macros that control the handling of
+			   initialization and termination routines.
+* Instruction Output::   Output of actual instructions.
+* Dispatch Tables::      Output of jump tables.
+* Exception Region Output:: Output of exception region code.
+* Alignment Output::     Pseudo ops for alignment and skipping data.
+@end menu
+
+@node File Framework
+@subsection The Overall Framework of an Assembler File
+@cindex assembler format
+@cindex output of assembler code
+
+@c prevent bad page break with this line
+This describes the overall framework of an assembler file.
+
+@table @code
+@findex ASM_FILE_START
+@item ASM_FILE_START (@var{stream})
+A C expression which outputs to the stdio stream @var{stream}
+some appropriate text to go at the start of an assembler file.
+
+Normally this macro is defined to output a line containing
+@samp{#NO_APP}, which is a comment that has no effect on most
+assemblers but tells the GNU assembler that it can save time by not
+checking for certain assembler constructs.
+
+On systems that use SDB, it is necessary to output certain commands;
+see @file{attasm.h}.
+
+@findex ASM_FILE_END
+@item ASM_FILE_END (@var{stream})
+A C expression which outputs to the stdio stream @var{stream}
+some appropriate text to go at the end of an assembler file.
+
+If this macro is not defined, the default is to output nothing
+special at the end of the file.  Most systems don't require any
+definition.
+
+On systems that use SDB, it is necessary to output certain commands;
+see @file{attasm.h}.
+
+@findex ASM_COMMENT_START
+@item ASM_COMMENT_START
+A C string constant describing how to begin a comment in the target
+assembler language.  The compiler assumes that the comment will end at
+the end of the line.
+
+@findex ASM_APP_ON
+@item ASM_APP_ON
+A C string constant for text to be output before each @code{asm}
+statement or group of consecutive ones.  Normally this is
+@code{"#APP"}, which is a comment that has no effect on most
+assemblers but tells the GNU assembler that it must check the lines
+that follow for all valid assembler constructs.
+
+@findex ASM_APP_OFF
+@item ASM_APP_OFF
+A C string constant for text to be output after each @code{asm}
+statement or group of consecutive ones.  Normally this is
+@code{"#NO_APP"}, which tells the GNU assembler to resume making the
+time-saving assumptions that are valid for ordinary compiler output.
+
+@findex ASM_OUTPUT_SOURCE_FILENAME
+@item ASM_OUTPUT_SOURCE_FILENAME (@var{stream}, @var{name})
+A C statement to output COFF information or DWARF debugging information
+which indicates that filename @var{name} is the current source file to
+the stdio stream @var{stream}.
+
+This macro need not be defined if the standard form of output
+for the file format in use is appropriate.
+
+@findex OUTPUT_QUOTED_STRING
+@item OUTPUT_QUOTED_STRING (@var{stream}, @var{string})
+A C statement to output the string @var{string} to the stdio stream
+@var{stream}.  If you do not call the function @code{output_quoted_string}
+in your config files, GCC will only call it to output filenames to
+the assembler source.  So you can use it to canonicalize the format
+of the filename using this macro.
+
+@findex ASM_OUTPUT_SOURCE_LINE
+@item ASM_OUTPUT_SOURCE_LINE (@var{stream}, @var{line})
+A C statement to output DBX or SDB debugging information before code
+for line number @var{line} of the current source file to the
+stdio stream @var{stream}.
+
+This macro need not be defined if the standard form of debugging
+information for the debugger in use is appropriate.
+
+@findex ASM_OUTPUT_IDENT
+@item ASM_OUTPUT_IDENT (@var{stream}, @var{string})
+A C statement to output something to the assembler file to handle a
+@samp{#ident} directive containing the text @var{string}.  If this
+macro is not defined, nothing is output for a @samp{#ident} directive.
+
+@findex OBJC_PROLOGUE
+@item OBJC_PROLOGUE
+A C statement to output any assembler statements which are required to
+precede any Objective-C object definitions or message sending.  The
+statement is executed only when compiling an Objective-C program.
+@end table
+
+@deftypefn {Target Hook} void TARGET_ASM_NAMED_SECTION (const char *@var{name}, unsigned int @var{flags}, unsigned int @var{align})
+Output assembly directives to switch to section @var{name}.  The section
+should have attributes as specified by @var{flags}, which is a bit mask
+of the @code{SECTION_*} flags defined in @file{output.h}.  If @var{align}
+is nonzero, it contains an alignment in bytes to be used for the section,
+otherwise some target default should be used.  Only targets that must 
+specify an alignment within the section directive need pay attention to
+@var{align} -- we will still use @code{ASM_OUTPUT_ALIGN}.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_HAVE_NAMED_SECTIONS
+This flag is true if the target supports @code{TARGET_ASM_NAMED_SECTION}.
+@end deftypefn
+
+@deftypefn {Target Hook} {unsigned int} TARGET_SECTION_TYPE_FLAGS (tree @var{decl}, const char *@var{name}, int @var{reloc})
+Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}
+based on a variable or function decl, a section name, and whether or not the
+declaration's initializer may contain runtime relocations.  @var{decl} may be
+ null, in which case read-write data should be assumed.
+
+The default version if this function handles choosing code vs data,
+read-only vs read-write data, and @code{flag_pic}.  You should only
+need to override this if your target has special flags that might be
+set via @code{__attribute__}.
+@end deftypefn
+
+@need 2000
+@node Data Output
+@subsection Output of Data
+
+
+@deftypevr {Target Hook} {const char *} TARGET_ASM_BYTE_OP
+@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_HI_OP
+@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_SI_OP
+@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_DI_OP
+@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_TI_OP
+@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_HI_OP
+@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_SI_OP
+@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_DI_OP
+@deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_TI_OP
+These hooks specify assembly directives for creating certain kinds
+of integer object.  The @code{TARGET_ASM_BYTE_OP} directive creates a
+byte-sized object, the @code{TARGET_ASM_ALIGNED_HI_OP} one creates an
+aligned two-byte object, and so on.  Any of the hooks may be
+@code{NULL}, indicating that no suitable directive is available.
+
+The compiler will print these strings at the start of a new line,
+followed immediately by the object's initial value.  In most cases,
+the string should contain a tab, a pseudo-op, and then another tab.
+@end deftypevr
+
+@deftypefn {Target Hook} bool TARGET_ASM_INTEGER (rtx @var{x}, unsigned int @var{size}, int @var{aligned_p})
+The @code{assemble_integer} function uses this hook to output an
+integer object.  @var{x} is the object's value, @var{size} is its size
+in bytes and @var{aligned_p} indicates whether it is aligned.  The
+function should return @code{true} if it was able to output the
+object.  If it returns false, @code{assemble_integer} will try to
+split the object into smaller parts.
+
+The default implementation of this hook will use the
+@code{TARGET_ASM_BYTE_OP} family of strings, returning @code{false}
+when the relevant string is @code{NULL}.
+@end deftypefn
+
+@table @code
+@findex OUTPUT_ADDR_CONST_EXTRA
+@item OUTPUT_ADDR_CONST_EXTRA (@var{stream}, @var{x}, @var{fail})
+A C statement to recognize @var{rtx} patterns that
+@code{output_addr_const} can't deal with, and output assembly code to
+@var{stream} corresponding to the pattern @var{x}.  This may be used to
+allow machine-dependent @code{UNSPEC}s to appear within constants.
+
+If @code{OUTPUT_ADDR_CONST_EXTRA} fails to recognize a pattern, it must
+@code{goto fail}, so that a standard error message is printed.  If it
+prints an error message itself, by calling, for example,
+@code{output_operand_lossage}, it may just complete normally.
+
+@findex ASM_OUTPUT_ASCII
+@item ASM_OUTPUT_ASCII (@var{stream}, @var{ptr}, @var{len})
+A C statement to output to the stdio stream @var{stream} an assembler
+instruction to assemble a string constant containing the @var{len}
+bytes at @var{ptr}.  @var{ptr} will be a C expression of type
+@code{char *} and @var{len} a C expression of type @code{int}.
+
+If the assembler has a @code{.ascii} pseudo-op as found in the
+Berkeley Unix assembler, do not define the macro
+@code{ASM_OUTPUT_ASCII}.
+
+@findex ASM_OUTPUT_FDESC
+@item ASM_OUTPUT_FDESC (@var{stream}, @var{decl}, @var{n})
+A C statement to output word @var{n} of a function descriptor for
+@var{decl}.  This must be defined if @code{TARGET_VTABLE_USES_DESCRIPTORS}
+is defined, and is otherwise unused.
+
+@findex CONSTANT_POOL_BEFORE_FUNCTION
+@item CONSTANT_POOL_BEFORE_FUNCTION
+You may define this macro as a C expression.  You should define the
+expression to have a nonzero value if GCC should output the constant
+pool for a function before the code for the function, or a zero value if
+GCC should output the constant pool after the function.  If you do
+not define this macro, the usual case, GCC will output the constant
+pool before the function.
+
+@findex ASM_OUTPUT_POOL_PROLOGUE
+@item ASM_OUTPUT_POOL_PROLOGUE (@var{file}, @var{funname}, @var{fundecl}, @var{size})
+A C statement to output assembler commands to define the start of the
+constant pool for a function.  @var{funname} is a string giving
+the name of the function.  Should the return type of the function
+be required, it can be obtained via @var{fundecl}.  @var{size}
+is the size, in bytes, of the constant pool that will be written
+immediately after this call.
+
+If no constant-pool prefix is required, the usual case, this macro need
+not be defined.
+
+@findex ASM_OUTPUT_SPECIAL_POOL_ENTRY
+@item ASM_OUTPUT_SPECIAL_POOL_ENTRY (@var{file}, @var{x}, @var{mode}, @var{align}, @var{labelno}, @var{jumpto})
+A C statement (with or without semicolon) to output a constant in the
+constant pool, if it needs special treatment.  (This macro need not do
+anything for RTL expressions that can be output normally.)
+
+The argument @var{file} is the standard I/O stream to output the
+assembler code on.  @var{x} is the RTL expression for the constant to
+output, and @var{mode} is the machine mode (in case @var{x} is a
+@samp{const_int}).  @var{align} is the required alignment for the value
+@var{x}; you should output an assembler directive to force this much
+alignment.
+
+The argument @var{labelno} is a number to use in an internal label for
+the address of this pool entry.  The definition of this macro is
+responsible for outputting the label definition at the proper place.
+Here is how to do this:
+
+@example
+ASM_OUTPUT_INTERNAL_LABEL (@var{file}, "LC", @var{labelno});
+@end example
+
+When you output a pool entry specially, you should end with a
+@code{goto} to the label @var{jumpto}.  This will prevent the same pool
+entry from being output a second time in the usual manner.
+
+You need not define this macro if it would do nothing.
+
+@findex CONSTANT_AFTER_FUNCTION_P
+@item CONSTANT_AFTER_FUNCTION_P (@var{exp})
+Define this macro as a C expression which is nonzero if the constant
+@var{exp}, of type @code{tree}, should be output after the code for a
+function.  The compiler will normally output all constants before the
+function; you need not define this macro if this is OK@.
+
+@findex ASM_OUTPUT_POOL_EPILOGUE
+@item ASM_OUTPUT_POOL_EPILOGUE (@var{file} @var{funname} @var{fundecl} @var{size})
+A C statement to output assembler commands to at the end of the constant
+pool for a function.  @var{funname} is a string giving the name of the
+function.  Should the return type of the function be required, you can
+obtain it via @var{fundecl}.  @var{size} is the size, in bytes, of the
+constant pool that GCC wrote immediately before this call.
+
+If no constant-pool epilogue is required, the usual case, you need not
+define this macro.
+
+@findex IS_ASM_LOGICAL_LINE_SEPARATOR
+@item IS_ASM_LOGICAL_LINE_SEPARATOR (@var{C})
+Define this macro as a C expression which is nonzero if @var{C} is
+used as a logical line separator by the assembler.
+
+If you do not define this macro, the default is that only
+the character @samp{;} is treated as a logical line separator.
+@end table
+
+@deftypevr {Target Hook} {const char *} TARGET_ASM_OPEN_PAREN
+@deftypevrx {Target Hook} {const char *} TARGET_ASM_CLOSE_PAREN
+These target hooks are C string constants, describing the syntax in the
+assembler for grouping arithmetic expressions.  If not overridden, they
+default to normal parentheses, which is correct for most assemblers.
+@end deftypevr
+
+  These macros are provided by @file{real.h} for writing the definitions
+of @code{ASM_OUTPUT_DOUBLE} and the like:
+
+@table @code
+@item REAL_VALUE_TO_TARGET_SINGLE (@var{x}, @var{l})
+@itemx REAL_VALUE_TO_TARGET_DOUBLE (@var{x}, @var{l})
+@itemx REAL_VALUE_TO_TARGET_LONG_DOUBLE (@var{x}, @var{l})
+@findex REAL_VALUE_TO_TARGET_SINGLE
+@findex REAL_VALUE_TO_TARGET_DOUBLE
+@findex REAL_VALUE_TO_TARGET_LONG_DOUBLE
+These translate @var{x}, of type @code{REAL_VALUE_TYPE}, to the target's
+floating point representation, and store its bit pattern in the array of
+@code{long int} whose address is @var{l}.  The number of elements in the
+output array is determined by the size of the desired target floating
+point data type: 32 bits of it go in each @code{long int} array
+element.  Each array element holds 32 bits of the result, even if
+@code{long int} is wider than 32 bits on the host machine.
+
+The array element values are designed so that you can print them out
+using @code{fprintf} in the order they should appear in the target
+machine's memory.
+
+@item REAL_VALUE_TO_DECIMAL (@var{x}, @var{format}, @var{string})
+@findex REAL_VALUE_TO_DECIMAL
+This macro converts @var{x}, of type @code{REAL_VALUE_TYPE}, to a
+decimal number and stores it as a string into @var{string}.
+You must pass, as @var{string}, the address of a long enough block
+of space to hold the result.
+
+The argument @var{format} is a @code{printf}-specification that serves
+as a suggestion for how to format the output string.
+@end table
+
+@node Uninitialized Data
+@subsection Output of Uninitialized Variables
+
+Each of the macros in this section is used to do the whole job of
+outputting a single uninitialized variable.
+
+@table @code
+@findex ASM_OUTPUT_COMMON
+@item ASM_OUTPUT_COMMON (@var{stream}, @var{name}, @var{size}, @var{rounded})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} the assembler definition of a common-label named
+@var{name} whose size is @var{size} bytes.  The variable @var{rounded}
+is the size rounded up to whatever alignment the caller wants.
+
+Use the expression @code{assemble_name (@var{stream}, @var{name})} to
+output the name itself; before and after that, output the additional
+assembler syntax for defining the name, and a newline.
+
+This macro controls how the assembler definitions of uninitialized
+common global variables are output.
+
+@findex ASM_OUTPUT_ALIGNED_COMMON
+@item ASM_OUTPUT_ALIGNED_COMMON (@var{stream}, @var{name}, @var{size}, @var{alignment})
+Like @code{ASM_OUTPUT_COMMON} except takes the required alignment as a
+separate, explicit argument.  If you define this macro, it is used in
+place of @code{ASM_OUTPUT_COMMON}, and gives you more flexibility in
+handling the required alignment of the variable.  The alignment is specified
+as the number of bits.
+
+@findex ASM_OUTPUT_ALIGNED_DECL_COMMON
+@item ASM_OUTPUT_ALIGNED_DECL_COMMON (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
+Like @code{ASM_OUTPUT_ALIGNED_COMMON} except that @var{decl} of the
+variable to be output, if there is one, or @code{NULL_TREE} if there
+is no corresponding variable.  If you define this macro, GCC will use it
+in place of both @code{ASM_OUTPUT_COMMON} and
+@code{ASM_OUTPUT_ALIGNED_COMMON}.  Define this macro when you need to see
+the variable's decl in order to chose what to output.
+
+@findex ASM_OUTPUT_SHARED_COMMON
+@item ASM_OUTPUT_SHARED_COMMON (@var{stream}, @var{name}, @var{size}, @var{rounded})
+If defined, it is similar to @code{ASM_OUTPUT_COMMON}, except that it
+is used when @var{name} is shared.  If not defined, @code{ASM_OUTPUT_COMMON}
+will be used.
+
+@findex ASM_OUTPUT_BSS
+@item ASM_OUTPUT_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{rounded})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} the assembler definition of uninitialized global @var{decl} named
+@var{name} whose size is @var{size} bytes.  The variable @var{rounded}
+is the size rounded up to whatever alignment the caller wants.
+
+Try to use function @code{asm_output_bss} defined in @file{varasm.c} when
+defining this macro.  If unable, use the expression
+@code{assemble_name (@var{stream}, @var{name})} to output the name itself;
+before and after that, output the additional assembler syntax for defining
+the name, and a newline.
+
+This macro controls how the assembler definitions of uninitialized global
+variables are output.  This macro exists to properly support languages like
+C++ which do not have @code{common} data.  However, this macro currently
+is not defined for all targets.  If this macro and
+@code{ASM_OUTPUT_ALIGNED_BSS} are not defined then @code{ASM_OUTPUT_COMMON}
+or @code{ASM_OUTPUT_ALIGNED_COMMON} or
+@code{ASM_OUTPUT_ALIGNED_DECL_COMMON} is used.
+
+@findex ASM_OUTPUT_ALIGNED_BSS
+@item ASM_OUTPUT_ALIGNED_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
+Like @code{ASM_OUTPUT_BSS} except takes the required alignment as a
+separate, explicit argument.  If you define this macro, it is used in
+place of @code{ASM_OUTPUT_BSS}, and gives you more flexibility in
+handling the required alignment of the variable.  The alignment is specified
+as the number of bits.
+
+Try to use function @code{asm_output_aligned_bss} defined in file
+@file{varasm.c} when defining this macro.
+
+@findex ASM_OUTPUT_SHARED_BSS
+@item ASM_OUTPUT_SHARED_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{rounded})
+If defined, it is similar to @code{ASM_OUTPUT_BSS}, except that it
+is used when @var{name} is shared.  If not defined, @code{ASM_OUTPUT_BSS}
+will be used.
+
+@findex ASM_OUTPUT_LOCAL
+@item ASM_OUTPUT_LOCAL (@var{stream}, @var{name}, @var{size}, @var{rounded})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} the assembler definition of a local-common-label named
+@var{name} whose size is @var{size} bytes.  The variable @var{rounded}
+is the size rounded up to whatever alignment the caller wants.
+
+Use the expression @code{assemble_name (@var{stream}, @var{name})} to
+output the name itself; before and after that, output the additional
+assembler syntax for defining the name, and a newline.
+
+This macro controls how the assembler definitions of uninitialized
+static variables are output.
+
+@findex ASM_OUTPUT_ALIGNED_LOCAL
+@item ASM_OUTPUT_ALIGNED_LOCAL (@var{stream}, @var{name}, @var{size}, @var{alignment})
+Like @code{ASM_OUTPUT_LOCAL} except takes the required alignment as a
+separate, explicit argument.  If you define this macro, it is used in
+place of @code{ASM_OUTPUT_LOCAL}, and gives you more flexibility in
+handling the required alignment of the variable.  The alignment is specified
+as the number of bits.
+
+@findex ASM_OUTPUT_ALIGNED_DECL_LOCAL
+@item ASM_OUTPUT_ALIGNED_DECL_LOCAL (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
+Like @code{ASM_OUTPUT_ALIGNED_DECL} except that @var{decl} of the
+variable to be output, if there is one, or @code{NULL_TREE} if there
+is no corresponding variable.  If you define this macro, GCC will use it
+in place of both @code{ASM_OUTPUT_DECL} and
+@code{ASM_OUTPUT_ALIGNED_DECL}.  Define this macro when you need to see
+the variable's decl in order to chose what to output.
+
+@findex ASM_OUTPUT_SHARED_LOCAL
+@item ASM_OUTPUT_SHARED_LOCAL (@var{stream}, @var{name}, @var{size}, @var{rounded})
+If defined, it is similar to @code{ASM_OUTPUT_LOCAL}, except that it
+is used when @var{name} is shared.  If not defined, @code{ASM_OUTPUT_LOCAL}
+will be used.
+@end table
+
+@node Label Output
+@subsection Output and Generation of Labels
+
+@c prevent bad page break with this line
+This is about outputting labels.
+
+@table @code
+@findex ASM_OUTPUT_LABEL
+@findex assemble_name
+@item ASM_OUTPUT_LABEL (@var{stream}, @var{name})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} the assembler definition of a label named @var{name}.
+Use the expression @code{assemble_name (@var{stream}, @var{name})} to
+output the name itself; before and after that, output the additional
+assembler syntax for defining the name, and a newline.
+
+@findex ASM_DECLARE_FUNCTION_NAME
+@item ASM_DECLARE_FUNCTION_NAME (@var{stream}, @var{name}, @var{decl})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} any text necessary for declaring the name @var{name} of a
+function which is being defined.  This macro is responsible for
+outputting the label definition (perhaps using
+@code{ASM_OUTPUT_LABEL}).  The argument @var{decl} is the
+@code{FUNCTION_DECL} tree node representing the function.
+
+If this macro is not defined, then the function name is defined in the
+usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}).
+
+@findex ASM_DECLARE_FUNCTION_SIZE
+@item ASM_DECLARE_FUNCTION_SIZE (@var{stream}, @var{name}, @var{decl})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} any text necessary for declaring the size of a function
+which is being defined.  The argument @var{name} is the name of the
+function.  The argument @var{decl} is the @code{FUNCTION_DECL} tree node
+representing the function.
+
+If this macro is not defined, then the function size is not defined.
+
+@findex ASM_DECLARE_OBJECT_NAME
+@item ASM_DECLARE_OBJECT_NAME (@var{stream}, @var{name}, @var{decl})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} any text necessary for declaring the name @var{name} of an
+initialized variable which is being defined.  This macro must output the
+label definition (perhaps using @code{ASM_OUTPUT_LABEL}).  The argument
+@var{decl} is the @code{VAR_DECL} tree node representing the variable.
+
+If this macro is not defined, then the variable name is defined in the
+usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}).
+
+@findex ASM_DECLARE_REGISTER_GLOBAL
+@item ASM_DECLARE_REGISTER_GLOBAL (@var{stream}, @var{decl}, @var{regno}, @var{name})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} any text necessary for claiming a register @var{regno}
+for a global variable @var{decl} with name @var{name}.
+
+If you don't define this macro, that is equivalent to defining it to do
+nothing.
+
+@findex  ASM_FINISH_DECLARE_OBJECT
+@item ASM_FINISH_DECLARE_OBJECT (@var{stream}, @var{decl}, @var{toplevel}, @var{atend})
+A C statement (sans semicolon) to finish up declaring a variable name
+once the compiler has processed its initializer fully and thus has had a
+chance to determine the size of an array when controlled by an
+initializer.  This is used on systems where it's necessary to declare
+something about the size of the object.
+
+If you don't define this macro, that is equivalent to defining it to do
+nothing.
+
+@findex ASM_GLOBALIZE_LABEL
+@item ASM_GLOBALIZE_LABEL (@var{stream}, @var{name})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} some commands that will make the label @var{name} global;
+that is, available for reference from other files.  Use the expression
+@code{assemble_name (@var{stream}, @var{name})} to output the name
+itself; before and after that, output the additional assembler syntax
+for making that name global, and a newline.
+
+@findex ASM_WEAKEN_LABEL
+@item ASM_WEAKEN_LABEL
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} some commands that will make the label @var{name} weak;
+that is, available for reference from other files but only used if
+no other definition is available.  Use the expression
+@code{assemble_name (@var{stream}, @var{name})} to output the name
+itself; before and after that, output the additional assembler syntax
+for making that name weak, and a newline.
+
+If you don't define this macro, GCC will not support weak
+symbols and you should not define the @code{SUPPORTS_WEAK} macro.
+
+@findex SUPPORTS_WEAK
+@item SUPPORTS_WEAK
+A C expression which evaluates to true if the target supports weak symbols.
+
+If you don't define this macro, @file{defaults.h} provides a default
+definition.  If @code{ASM_WEAKEN_LABEL} is defined, the default
+definition is @samp{1}; otherwise, it is @samp{0}.  Define this macro if
+you want to control weak symbol support with a compiler flag such as
+@option{-melf}.
+
+@findex MAKE_DECL_ONE_ONLY (@var{decl})
+@item MAKE_DECL_ONE_ONLY
+A C statement (sans semicolon) to mark @var{decl} to be emitted as a
+public symbol such that extra copies in multiple translation units will
+be discarded by the linker.  Define this macro if your object file
+format provides support for this concept, such as the @samp{COMDAT}
+section flags in the Microsoft Windows PE/COFF format, and this support
+requires changes to @var{decl}, such as putting it in a separate section.
+
+@findex SUPPORTS_ONE_ONLY
+@item SUPPORTS_ONE_ONLY
+A C expression which evaluates to true if the target supports one-only
+semantics.
+
+If you don't define this macro, @file{varasm.c} provides a default
+definition.  If @code{MAKE_DECL_ONE_ONLY} is defined, the default
+definition is @samp{1}; otherwise, it is @samp{0}.  Define this macro if
+you want to control one-only symbol support with a compiler flag, or if
+setting the @code{DECL_ONE_ONLY} flag is enough to mark a declaration to
+be emitted as one-only.
+
+@findex ASM_OUTPUT_EXTERNAL
+@item ASM_OUTPUT_EXTERNAL (@var{stream}, @var{decl}, @var{name})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} any text necessary for declaring the name of an external
+symbol named @var{name} which is referenced in this compilation but
+not defined.  The value of @var{decl} is the tree node for the
+declaration.
+
+This macro need not be defined if it does not need to output anything.
+The GNU assembler and most Unix assemblers don't require anything.
+
+@findex ASM_OUTPUT_EXTERNAL_LIBCALL
+@item ASM_OUTPUT_EXTERNAL_LIBCALL (@var{stream}, @var{symref})
+A C statement (sans semicolon) to output on @var{stream} an assembler
+pseudo-op to declare a library function name external.  The name of the
+library function is given by @var{symref}, which has type @code{rtx} and
+is a @code{symbol_ref}.
+
+This macro need not be defined if it does not need to output anything.
+The GNU assembler and most Unix assemblers don't require anything.
+
+@findex ASM_OUTPUT_LABELREF
+@item ASM_OUTPUT_LABELREF (@var{stream}, @var{name})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} a reference in assembler syntax to a label named
+@var{name}.  This should add @samp{_} to the front of the name, if that
+is customary on your operating system, as it is in most Berkeley Unix
+systems.  This macro is used in @code{assemble_name}.
+
+@findex ASM_OUTPUT_SYMBOL_REF
+@item ASM_OUTPUT_SYMBOL_REF (@var{stream}, @var{sym})
+A C statement (sans semicolon) to output a reference to
+@code{SYMBOL_REF} @var{sym}.  If not defined, @code{assemble_name}
+will be used to output the name of the symbol.  This macro may be used
+to modify the way a symbol is referenced depending on information
+encoded by @code{ENCODE_SECTION_INFO}.
+
+@findex ASM_OUTPUT_LABEL_REF
+@item ASM_OUTPUT_LABEL_REF (@var{stream}, @var{buf})
+A C statement (sans semicolon) to output a reference to @var{buf}, the
+result of ASM_GENERATE_INTERNAL_LABEL.  If not defined,
+@code{assemble_name} will be used to output the name of the symbol.
+This macro is not used by @code{output_asm_label}, or the @code{%l}
+specifier that calls it; the intention is that this macro should be set
+when it is necessary to output a label differently when its address
+is being taken.
+
+@findex ASM_OUTPUT_INTERNAL_LABEL
+@item ASM_OUTPUT_INTERNAL_LABEL (@var{stream}, @var{prefix}, @var{num})
+A C statement to output to the stdio stream @var{stream} a label whose
+name is made from the string @var{prefix} and the number @var{num}.
+
+It is absolutely essential that these labels be distinct from the labels
+used for user-level functions and variables.  Otherwise, certain programs
+will have name conflicts with internal labels.
+
+It is desirable to exclude internal labels from the symbol table of the
+object file.  Most assemblers have a naming convention for labels that
+should be excluded; on many systems, the letter @samp{L} at the
+beginning of a label has this effect.  You should find out what
+convention your system uses, and follow it.
+
+The usual definition of this macro is as follows:
+
+@example
+fprintf (@var{stream}, "L%s%d:\n", @var{prefix}, @var{num})
+@end example
+
+@findex ASM_OUTPUT_DEBUG_LABEL
+@item ASM_OUTPUT_DEBUG_LABEL (@var{stream}, @var{prefix}, @var{num})
+A C statement to output to the stdio stream @var{stream} a debug info
+label whose name is made from the string @var{prefix} and the number
+@var{num}.  This is useful for VLIW targets, where debug info labels
+may need to be treated differently than branch target labels.  On some
+systems, branch target labels must be at the beginning of instruction
+bundles, but debug info labels can occur in the middle of instruction
+bundles.
+
+If this macro is not defined, then @code{ASM_OUTPUT_INTERNAL_LABEL} will be
+used.
+
+@findex ASM_OUTPUT_ALTERNATE_LABEL_NAME
+@item ASM_OUTPUT_ALTERNATE_LABEL_NAME (@var{stream}, @var{string})
+A C statement to output to the stdio stream @var{stream} the string
+@var{string}.
+
+The default definition of this macro is as follows:
+
+@example
+fprintf (@var{stream}, "%s:\n", LABEL_ALTERNATE_NAME (INSN))
+@end example
+
+@findex ASM_GENERATE_INTERNAL_LABEL
+@item ASM_GENERATE_INTERNAL_LABEL (@var{string}, @var{prefix}, @var{num})
+A C statement to store into the string @var{string} a label whose name
+is made from the string @var{prefix} and the number @var{num}.
+
+This string, when output subsequently by @code{assemble_name}, should
+produce the output that @code{ASM_OUTPUT_INTERNAL_LABEL} would produce
+with the same @var{prefix} and @var{num}.
+
+If the string begins with @samp{*}, then @code{assemble_name} will
+output the rest of the string unchanged.  It is often convenient for
+@code{ASM_GENERATE_INTERNAL_LABEL} to use @samp{*} in this way.  If the
+string doesn't start with @samp{*}, then @code{ASM_OUTPUT_LABELREF} gets
+to output the string, and may change it.  (Of course,
+@code{ASM_OUTPUT_LABELREF} is also part of your machine description, so
+you should know what it does on your machine.)
+
+@findex ASM_FORMAT_PRIVATE_NAME
+@item ASM_FORMAT_PRIVATE_NAME (@var{outvar}, @var{name}, @var{number})
+A C expression to assign to @var{outvar} (which is a variable of type
+@code{char *}) a newly allocated string made from the string
+@var{name} and the number @var{number}, with some suitable punctuation
+added.  Use @code{alloca} to get space for the string.
+
+The string will be used as an argument to @code{ASM_OUTPUT_LABELREF} to
+produce an assembler label for an internal static variable whose name is
+@var{name}.  Therefore, the string must be such as to result in valid
+assembler code.  The argument @var{number} is different each time this
+macro is executed; it prevents conflicts between similarly-named
+internal static variables in different scopes.
+
+Ideally this string should not be a valid C identifier, to prevent any
+conflict with the user's own symbols.  Most assemblers allow periods
+or percent signs in assembler symbols; putting at least one of these
+between the name and the number will suffice.
+
+@findex ASM_OUTPUT_DEF
+@item ASM_OUTPUT_DEF (@var{stream}, @var{name}, @var{value})
+A C statement to output to the stdio stream @var{stream} assembler code
+which defines (equates) the symbol @var{name} to have the value @var{value}.
+
+@findex SET_ASM_OP
+If @code{SET_ASM_OP} is defined, a default definition is provided which is
+correct for most systems.
+
+@findex ASM_OUTPUT_DEF_FROM_DECLS
+@item ASM_OUTPUT_DEF_FROM_DECLS (@var{stream}, @var{decl_of_name}, @var{decl_of_value})
+A C statement to output to the stdio stream @var{stream} assembler code
+which defines (equates) the symbol whose tree node is @var{decl_of_name}
+to have the value of the tree node @var{decl_of_value}.  This macro will
+be used in preference to @samp{ASM_OUTPUT_DEF} if it is defined and if
+the tree nodes are available.
+
+@findex ASM_OUTPUT_DEFINE_LABEL_DIFFERENCE_SYMBOL
+@item ASM_OUTPUT_DEFINE_LABEL_DIFFERENCE_SYMBOL (@var{stream}, @var{symbol}, @var{high}, @var{low})
+A C statement to output to the stdio stream @var{stream} assembler code
+which defines (equates) the symbol @var{symbol} to have a value equal to
+the difference of the two symbols @var{high} and @var{low},
+i.e.@: @var{high} minus @var{low}.  GCC guarantees that the symbols @var{high}
+and @var{low} are already known by the assembler so that the difference
+resolves into a constant.
+
+@findex SET_ASM_OP
+If @code{SET_ASM_OP} is defined, a default definition is provided which is
+correct for most systems.
+
+@findex ASM_OUTPUT_WEAK_ALIAS
+@item ASM_OUTPUT_WEAK_ALIAS (@var{stream}, @var{name}, @var{value})
+A C statement to output to the stdio stream @var{stream} assembler code
+which defines (equates) the weak symbol @var{name} to have the value
+@var{value}.  If @var{value} is @code{NULL}, it defines @var{name} as
+an undefined weak symbol.
+
+Define this macro if the target only supports weak aliases; define
+@code{ASM_OUTPUT_DEF} instead if possible.
+
+@findex OBJC_GEN_METHOD_LABEL
+@item OBJC_GEN_METHOD_LABEL (@var{buf}, @var{is_inst}, @var{class_name}, @var{cat_name}, @var{sel_name})
+Define this macro to override the default assembler names used for
+Objective-C methods.
+
+The default name is a unique method number followed by the name of the
+class (e.g.@: @samp{_1_Foo}).  For methods in categories, the name of
+the category is also included in the assembler name (e.g.@:
+@samp{_1_Foo_Bar}).
+
+These names are safe on most systems, but make debugging difficult since
+the method's selector is not present in the name.  Therefore, particular
+systems define other ways of computing names.
+
+@var{buf} is an expression of type @code{char *} which gives you a
+buffer in which to store the name; its length is as long as
+@var{class_name}, @var{cat_name} and @var{sel_name} put together, plus
+50 characters extra.
+
+The argument @var{is_inst} specifies whether the method is an instance
+method or a class method; @var{class_name} is the name of the class;
+@var{cat_name} is the name of the category (or @code{NULL} if the method is not
+in a category); and @var{sel_name} is the name of the selector.
+
+On systems where the assembler can handle quoted names, you can use this
+macro to provide more human-readable names.
+
+@findex ASM_DECLARE_CLASS_REFERENCE
+@item ASM_DECLARE_CLASS_REFERENCE (@var{stream}, @var{name})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} commands to declare that the label @var{name} is an
+Objective-C class reference.  This is only needed for targets whose
+linkers have special support for NeXT-style runtimes.
+
+@findex ASM_DECLARE_UNRESOLVED_REFERENCE
+@item ASM_DECLARE_UNRESOLVED_REFERENCE (@var{stream}, @var{name})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} commands to declare that the label @var{name} is an
+unresolved Objective-C class reference.  This is only needed for targets
+whose linkers have special support for NeXT-style runtimes.
+@end table
+
+@node Initialization
+@subsection How Initialization Functions Are Handled
+@cindex initialization routines
+@cindex termination routines
+@cindex constructors, output of
+@cindex destructors, output of
+
+The compiled code for certain languages includes @dfn{constructors}
+(also called @dfn{initialization routines})---functions to initialize
+data in the program when the program is started.  These functions need
+to be called before the program is ``started''---that is to say, before
+@code{main} is called.
+
+Compiling some languages generates @dfn{destructors} (also called
+@dfn{termination routines}) that should be called when the program
+terminates.
+
+To make the initialization and termination functions work, the compiler
+must output something in the assembler code to cause those functions to
+be called at the appropriate time.  When you port the compiler to a new
+system, you need to specify how to do this.
+
+There are two major ways that GCC currently supports the execution of
+initialization and termination functions.  Each way has two variants.
+Much of the structure is common to all four variations.
+
+@findex __CTOR_LIST__
+@findex __DTOR_LIST__
+The linker must build two lists of these functions---a list of
+initialization functions, called @code{__CTOR_LIST__}, and a list of
+termination functions, called @code{__DTOR_LIST__}.
+
+Each list always begins with an ignored function pointer (which may hold
+0, @minus{}1, or a count of the function pointers after it, depending on
+the environment).  This is followed by a series of zero or more function
+pointers to constructors (or destructors), followed by a function
+pointer containing zero.
+
+Depending on the operating system and its executable file format, either
+@file{crtstuff.c} or @file{libgcc2.c} traverses these lists at startup
+time and exit time.  Constructors are called in reverse order of the
+list; destructors in forward order.
+
+The best way to handle static constructors works only for object file
+formats which provide arbitrarily-named sections.  A section is set
+aside for a list of constructors, and another for a list of destructors.
+Traditionally these are called @samp{.ctors} and @samp{.dtors}.  Each
+object file that defines an initialization function also puts a word in
+the constructor section to point to that function.  The linker
+accumulates all these words into one contiguous @samp{.ctors} section.
+Termination functions are handled similarly.
+
+This method will be chosen as the default by @file{target-def.h} if
+@code{TARGET_ASM_NAMED_SECTION} is defined.  A target that does not
+support arbitrary sections, but does support special designated 
+constructor and destructor sections may define @code{CTORS_SECTION_ASM_OP}
+and @code{DTORS_SECTION_ASM_OP} to achieve the same effect.
+
+When arbitrary sections are available, there are two variants, depending
+upon how the code in @file{crtstuff.c} is called.  On systems that
+support a @dfn{.init} section which is executed at program startup,
+parts of @file{crtstuff.c} are compiled into that section.  The
+program is linked by the @code{gcc} driver like this:
+
+@example
+ld -o @var{output_file} crti.o crtbegin.o @dots{} -lgcc crtend.o crtn.o
+@end example
+
+The prologue of a function (@code{__init}) appears in the @code{.init}
+section of @file{crti.o}; the epilogue appears in @file{crtn.o}.  Likewise
+for the function @code{__fini} in the @dfn{.fini} section.  Normally these
+files are provided by the operating system or by the GNU C library, but
+are provided by GCC for a few targets.
+
+The objects @file{crtbegin.o} and @file{crtend.o} are (for most targets)
+compiled from @file{crtstuff.c}.  They contain, among other things, code
+fragments within the @code{.init} and @code{.fini} sections that branch
+to routines in the @code{.text} section.  The linker will pull all parts
+of a section together, which results in a complete @code{__init} function
+that invokes the routines we need at startup.
+
+To use this variant, you must define the @code{INIT_SECTION_ASM_OP}
+macro properly.
+
+If no init section is available, when GCC compiles any function called
+@code{main} (or more accurately, any function designated as a program
+entry point by the language front end calling @code{expand_main_function}),
+it inserts a procedure call to @code{__main} as the first executable code
+after the function prologue.  The @code{__main} function is defined
+in @file{libgcc2.c} and runs the global constructors.
+
+In file formats that don't support arbitrary sections, there are again
+two variants.  In the simplest variant, the GNU linker (GNU @code{ld})
+and an `a.out' format must be used.  In this case,
+@code{TARGET_ASM_CONSTRUCTOR} is defined to produce a @code{.stabs}
+entry of type @samp{N_SETT}, referencing the name @code{__CTOR_LIST__},
+and with the address of the void function containing the initialization
+code as its value.  The GNU linker recognizes this as a request to add
+the value to a @dfn{set}; the values are accumulated, and are eventually
+placed in the executable as a vector in the format described above, with
+a leading (ignored) count and a trailing zero element.
+@code{TARGET_ASM_DESTRUCTOR} is handled similarly.  Since no init
+section is available, the absence of @code{INIT_SECTION_ASM_OP} causes
+the compilation of @code{main} to call @code{__main} as above, starting
+the initialization process.
+
+The last variant uses neither arbitrary sections nor the GNU linker.
+This is preferable when you want to do dynamic linking and when using
+file formats which the GNU linker does not support, such as `ECOFF'@.  In
+this case, @code{TARGET_HAVE_CTORS_DTORS} is false, initialization and
+termination functions are recognized simply by their names.  This requires
+an extra program in the linkage step, called @command{collect2}.  This program
+pretends to be the linker, for use with GCC; it does its job by running
+the ordinary linker, but also arranges to include the vectors of
+initialization and termination functions.  These functions are called
+via @code{__main} as described above.  In order to use this method,
+@code{use_collect2} must be defined in the target in @file{config.gcc}.
+
+@ifinfo
+The following section describes the specific macros that control and
+customize the handling of initialization and termination functions.
+@end ifinfo
+
+@node Macros for Initialization
+@subsection Macros Controlling Initialization Routines
+
+Here are the macros that control how the compiler handles initialization
+and termination functions:
+
+@table @code
+@findex INIT_SECTION_ASM_OP
+@item INIT_SECTION_ASM_OP
+If defined, a C string constant, including spacing, for the assembler
+operation to identify the following data as initialization code.  If not
+defined, GCC will assume such a section does not exist.  When you are
+using special sections for initialization and termination functions, this
+macro also controls how @file{crtstuff.c} and @file{libgcc2.c} arrange to
+run the initialization functions.
+
+@item HAS_INIT_SECTION
+@findex HAS_INIT_SECTION
+If defined, @code{main} will not call @code{__main} as described above.
+This macro should be defined for systems that control start-up code
+on a symbol-by-symbol basis, such as OSF/1, and should not
+be defined explicitly for systems that support @code{INIT_SECTION_ASM_OP}.
+
+@item LD_INIT_SWITCH
+@findex LD_INIT_SWITCH
+If defined, a C string constant for a switch that tells the linker that
+the following symbol is an initialization routine.
+
+@item LD_FINI_SWITCH
+@findex LD_FINI_SWITCH
+If defined, a C string constant for a switch that tells the linker that
+the following symbol is a finalization routine.
+
+@item COLLECT_SHARED_INIT_FUNC (@var{stream}, @var{func})
+If defined, a C statement that will write a function that can be
+automatically called when a shared library is loaded.  The function
+should call @var{func}, which takes no arguments.  If not defined, and
+the object format requires an explicit initialization function, then a
+function called @code{_GLOBAL__DI} will be generated.
+
+This function and the following one are used by collect2 when linking a
+shared library that needs constructors or destructors, or has DWARF2 
+exception tables embedded in the code.
+
+@item COLLECT_SHARED_FINI_FUNC (@var{stream}, @var{func})
+If defined, a C statement that will write a function that can be
+automatically called when a shared library is unloaded.  The function
+should call @var{func}, which takes no arguments.  If not defined, and
+the object format requires an explicit finalization function, then a
+function called @code{_GLOBAL__DD} will be generated.
+
+@item INVOKE__main
+@findex INVOKE__main
+If defined, @code{main} will call @code{__main} despite the presence of
+@code{INIT_SECTION_ASM_OP}.  This macro should be defined for systems
+where the init section is not actually run automatically, but is still
+useful for collecting the lists of constructors and destructors.
+
+@item SUPPORTS_INIT_PRIORITY
+@findex SUPPORTS_INIT_PRIORITY
+If nonzero, the C++ @code{init_priority} attribute is supported and the
+compiler should emit instructions to control the order of initialization
+of objects.  If zero, the compiler will issue an error message upon
+encountering an @code{init_priority} attribute.
+@end table
+
+@deftypefn {Target Hook} bool TARGET_HAVE_CTORS_DTORS
+This value is true if the target supports some ``native'' method of
+collecting constructors and destructors to be run at startup and exit.
+It is false if we must use @command{collect2}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_ASM_CONSTRUCTOR (rtx @var{symbol}, int @var{priority})
+If defined, a function that outputs assembler code to arrange to call
+the function referenced by @var{symbol} at initialization time.
+
+Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking
+no arguments and with no return value.  If the target supports initialization
+priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};
+otherwise it must be @code{DEFAULT_INIT_PRIORITY}.
+
+If this macro is not defined by the target, a suitable default will
+be chosen if (1) the target supports arbitrary section names, (2) the
+target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}
+is not defined.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_ASM_DESTRUCTOR (rtx @var{symbol}, int @var{priority})
+This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination
+functions rather than initialization functions.
+@end deftypefn
+
+If @code{TARGET_HAVE_CTORS_DTORS} is true, the initialization routine
+generated for the generated object file will have static linkage.
+
+If your system uses @command{collect2} as the means of processing
+constructors, then that program normally uses @command{nm} to scan
+an object file for constructor functions to be called.
+
+On certain kinds of systems, you can define these macros to make
+@command{collect2} work faster (and, in some cases, make it work at all):
+
+@table @code
+@findex OBJECT_FORMAT_COFF
+@item OBJECT_FORMAT_COFF
+Define this macro if the system uses COFF (Common Object File Format)
+object files, so that @command{collect2} can assume this format and scan
+object files directly for dynamic constructor/destructor functions.
+
+@findex OBJECT_FORMAT_ROSE
+@item OBJECT_FORMAT_ROSE
+Define this macro if the system uses ROSE format object files, so that
+@command{collect2} can assume this format and scan object files directly
+for dynamic constructor/destructor functions.
+
+These macros are effective only in a native compiler; @command{collect2} as
+part of a cross compiler always uses @command{nm} for the target machine.
+
+@findex REAL_NM_FILE_NAME
+@item REAL_NM_FILE_NAME
+Define this macro as a C string constant containing the file name to use
+to execute @command{nm}.  The default is to search the path normally for
+@command{nm}.
+
+If your system supports shared libraries and has a program to list the
+dynamic dependencies of a given library or executable, you can define
+these macros to enable support for running initialization and
+termination functions in shared libraries:
+
+@findex LDD_SUFFIX
+@item LDD_SUFFIX
+Define this macro to a C string constant containing the name of the program
+which lists dynamic dependencies, like @command{"ldd"} under SunOS 4.
+
+@findex PARSE_LDD_OUTPUT
+@item PARSE_LDD_OUTPUT (@var{ptr})
+Define this macro to be C code that extracts filenames from the output
+of the program denoted by @code{LDD_SUFFIX}.  @var{ptr} is a variable
+of type @code{char *} that points to the beginning of a line of output
+from @code{LDD_SUFFIX}.  If the line lists a dynamic dependency, the
+code must advance @var{ptr} to the beginning of the filename on that
+line.  Otherwise, it must set @var{ptr} to @code{NULL}.
+@end table
+
+@node Instruction Output
+@subsection Output of Assembler Instructions
+
+@c prevent bad page break with this line
+This describes assembler instruction output.
+
+@table @code
+@findex REGISTER_NAMES
+@item REGISTER_NAMES
+A C initializer containing the assembler's names for the machine
+registers, each one as a C string constant.  This is what translates
+register numbers in the compiler into assembler language.
+
+@findex ADDITIONAL_REGISTER_NAMES
+@item ADDITIONAL_REGISTER_NAMES
+If defined, a C initializer for an array of structures containing a name
+and a register number.  This macro defines additional names for hard
+registers, thus allowing the @code{asm} option in declarations to refer
+to registers using alternate names.
+
+@findex ASM_OUTPUT_OPCODE
+@item ASM_OUTPUT_OPCODE (@var{stream}, @var{ptr})
+Define this macro if you are using an unusual assembler that
+requires different names for the machine instructions.
+
+The definition is a C statement or statements which output an
+assembler instruction opcode to the stdio stream @var{stream}.  The
+macro-operand @var{ptr} is a variable of type @code{char *} which
+points to the opcode name in its ``internal'' form---the form that is
+written in the machine description.  The definition should output the
+opcode name to @var{stream}, performing any translation you desire, and
+increment the variable @var{ptr} to point at the end of the opcode
+so that it will not be output twice.
+
+In fact, your macro definition may process less than the entire opcode
+name, or more than the opcode name; but if you want to process text
+that includes @samp{%}-sequences to substitute operands, you must take
+care of the substitution yourself.  Just be sure to increment
+@var{ptr} over whatever text should not be output normally.
+
+@findex recog_data.operand
+If you need to look at the operand values, they can be found as the
+elements of @code{recog_data.operand}.
+
+If the macro definition does nothing, the instruction is output
+in the usual way.
+
+@findex FINAL_PRESCAN_INSN
+@item FINAL_PRESCAN_INSN (@var{insn}, @var{opvec}, @var{noperands})
+If defined, a C statement to be executed just prior to the output of
+assembler code for @var{insn}, to modify the extracted operands so
+they will be output differently.
+
+Here the argument @var{opvec} is the vector containing the operands
+extracted from @var{insn}, and @var{noperands} is the number of
+elements of the vector which contain meaningful data for this insn.
+The contents of this vector are what will be used to convert the insn
+template into assembler code, so you can change the assembler output
+by changing the contents of the vector.
+
+This macro is useful when various assembler syntaxes share a single
+file of instruction patterns; by defining this macro differently, you
+can cause a large class of instructions to be output differently (such
+as with rearranged operands).  Naturally, variations in assembler
+syntax affecting individual insn patterns ought to be handled by
+writing conditional output routines in those patterns.
+
+If this macro is not defined, it is equivalent to a null statement.
+
+@findex FINAL_PRESCAN_LABEL
+@item FINAL_PRESCAN_LABEL
+If defined, @code{FINAL_PRESCAN_INSN} will be called on each
+@code{CODE_LABEL}.  In that case, @var{opvec} will be a null pointer and
+@var{noperands} will be zero.
+
+@findex PRINT_OPERAND
+@item PRINT_OPERAND (@var{stream}, @var{x}, @var{code})
+A C compound statement to output to stdio stream @var{stream} the
+assembler syntax for an instruction operand @var{x}.  @var{x} is an
+RTL expression.
+
+@var{code} is a value that can be used to specify one of several ways
+of printing the operand.  It is used when identical operands must be
+printed differently depending on the context.  @var{code} comes from
+the @samp{%} specification that was used to request printing of the
+operand.  If the specification was just @samp{%@var{digit}} then
+@var{code} is 0; if the specification was @samp{%@var{ltr}
+@var{digit}} then @var{code} is the ASCII code for @var{ltr}.
+
+@findex reg_names
+If @var{x} is a register, this macro should print the register's name.
+The names can be found in an array @code{reg_names} whose type is
+@code{char *[]}.  @code{reg_names} is initialized from
+@code{REGISTER_NAMES}.
+
+When the machine description has a specification @samp{%@var{punct}}
+(a @samp{%} followed by a punctuation character), this macro is called
+with a null pointer for @var{x} and the punctuation character for
+@var{code}.
+
+@findex PRINT_OPERAND_PUNCT_VALID_P
+@item PRINT_OPERAND_PUNCT_VALID_P (@var{code})
+A C expression which evaluates to true if @var{code} is a valid
+punctuation character for use in the @code{PRINT_OPERAND} macro.  If
+@code{PRINT_OPERAND_PUNCT_VALID_P} is not defined, it means that no
+punctuation characters (except for the standard one, @samp{%}) are used
+in this way.
+
+@findex PRINT_OPERAND_ADDRESS
+@item PRINT_OPERAND_ADDRESS (@var{stream}, @var{x})
+A C compound statement to output to stdio stream @var{stream} the
+assembler syntax for an instruction operand that is a memory reference
+whose address is @var{x}.  @var{x} is an RTL expression.
+
+@cindex @code{ENCODE_SECTION_INFO} usage
+On some machines, the syntax for a symbolic address depends on the
+section that the address refers to.  On these machines, define the macro
+@code{ENCODE_SECTION_INFO} to store the information into the
+@code{symbol_ref}, and then check for it here.  @xref{Assembler Format}.
+
+@findex DBR_OUTPUT_SEQEND
+@findex dbr_sequence_length
+@item DBR_OUTPUT_SEQEND(@var{file})
+A C statement, to be executed after all slot-filler instructions have
+been output.  If necessary, call @code{dbr_sequence_length} to
+determine the number of slots filled in a sequence (zero if not
+currently outputting a sequence), to decide how many no-ops to output,
+or whatever.
+
+Don't define this macro if it has nothing to do, but it is helpful in
+reading assembly output if the extent of the delay sequence is made
+explicit (e.g.@: with white space).
+
+@findex final_sequence
+Note that output routines for instructions with delay slots must be
+prepared to deal with not being output as part of a sequence
+(i.e.@: when the scheduling pass is not run, or when no slot fillers could be
+found.)  The variable @code{final_sequence} is null when not
+processing a sequence, otherwise it contains the @code{sequence} rtx
+being output.
+
+@findex REGISTER_PREFIX
+@findex LOCAL_LABEL_PREFIX
+@findex USER_LABEL_PREFIX
+@findex IMMEDIATE_PREFIX
+@findex asm_fprintf
+@item REGISTER_PREFIX
+@itemx LOCAL_LABEL_PREFIX
+@itemx USER_LABEL_PREFIX
+@itemx IMMEDIATE_PREFIX
+If defined, C string expressions to be used for the @samp{%R}, @samp{%L},
+@samp{%U}, and @samp{%I} options of @code{asm_fprintf} (see
+@file{final.c}).  These are useful when a single @file{md} file must
+support multiple assembler formats.  In that case, the various @file{tm.h}
+files can define these macros differently.
+
+@item ASM_FPRINTF_EXTENSIONS(@var{file}, @var{argptr}, @var{format})
+@findex ASM_FPRINTF_EXTENSIONS
+If defined this macro should expand to a series of @code{case}
+statements which will be parsed inside the @code{switch} statement of
+the @code{asm_fprintf} function.  This allows targets to define extra
+printf formats which may useful when generating their assembler
+statements.  Note that upper case letters are reserved for future
+generic extensions to asm_fprintf, and so are not available to target
+specific code.  The output file is given by the parameter @var{file}.
+The varargs input pointer is @var{argptr} and the rest of the format
+string, starting the character after the one that is being switched
+upon, is pointed to by @var{format}.
+
+@findex ASSEMBLER_DIALECT
+@item ASSEMBLER_DIALECT
+If your target supports multiple dialects of assembler language (such as
+different opcodes), define this macro as a C expression that gives the
+numeric index of the assembler language dialect to use, with zero as the
+first variant.
+
+If this macro is defined, you may use constructs of the form
+@smallexample
+@samp{@{option0|option1|option2@dots{}@}} 
+@end smallexample
+@noindent
+in the output templates of patterns (@pxref{Output Template}) or in the
+first argument of @code{asm_fprintf}.  This construct outputs
+@samp{option0}, @samp{option1}, @samp{option2}, etc., if the value of
+@code{ASSEMBLER_DIALECT} is zero, one, two, etc.  Any special characters
+within these strings retain their usual meaning.  If there are fewer
+alternatives within the braces than the value of
+@code{ASSEMBLER_DIALECT}, the construct outputs nothing.
+
+If you do not define this macro, the characters @samp{@{}, @samp{|} and
+@samp{@}} do not have any special meaning when used in templates or
+operands to @code{asm_fprintf}.
+
+Define the macros @code{REGISTER_PREFIX}, @code{LOCAL_LABEL_PREFIX},
+@code{USER_LABEL_PREFIX} and @code{IMMEDIATE_PREFIX} if you can express
+the variations in assembler language syntax with that mechanism.  Define
+@code{ASSEMBLER_DIALECT} and use the @samp{@{option0|option1@}} syntax
+if the syntax variant are larger and involve such things as different
+opcodes or operand order.
+
+@findex ASM_OUTPUT_REG_PUSH
+@item ASM_OUTPUT_REG_PUSH (@var{stream}, @var{regno})
+A C expression to output to @var{stream} some assembler code
+which will push hard register number @var{regno} onto the stack.
+The code need not be optimal, since this macro is used only when
+profiling.
+
+@findex ASM_OUTPUT_REG_POP
+@item ASM_OUTPUT_REG_POP (@var{stream}, @var{regno})
+A C expression to output to @var{stream} some assembler code
+which will pop hard register number @var{regno} off of the stack.
+The code need not be optimal, since this macro is used only when
+profiling.
+@end table
+
+@node Dispatch Tables
+@subsection Output of Dispatch Tables
+
+@c prevent bad page break with this line
+This concerns dispatch tables.
+
+@table @code
+@cindex dispatch table
+@findex ASM_OUTPUT_ADDR_DIFF_ELT
+@item ASM_OUTPUT_ADDR_DIFF_ELT (@var{stream}, @var{body}, @var{value}, @var{rel})
+A C statement to output to the stdio stream @var{stream} an assembler
+pseudo-instruction to generate a difference between two labels.
+@var{value} and @var{rel} are the numbers of two internal labels.  The
+definitions of these labels are output using
+@code{ASM_OUTPUT_INTERNAL_LABEL}, and they must be printed in the same
+way here.  For example,
+
+@example
+fprintf (@var{stream}, "\t.word L%d-L%d\n",
+         @var{value}, @var{rel})
+@end example
+
+You must provide this macro on machines where the addresses in a
+dispatch table are relative to the table's own address.  If defined, GCC
+will also use this macro on all machines when producing PIC@.
+@var{body} is the body of the @code{ADDR_DIFF_VEC}; it is provided so that the
+mode and flags can be read.
+
+@findex ASM_OUTPUT_ADDR_VEC_ELT
+@item ASM_OUTPUT_ADDR_VEC_ELT (@var{stream}, @var{value})
+This macro should be provided on machines where the addresses
+in a dispatch table are absolute.
+
+The definition should be a C statement to output to the stdio stream
+@var{stream} an assembler pseudo-instruction to generate a reference to
+a label.  @var{value} is the number of an internal label whose
+definition is output using @code{ASM_OUTPUT_INTERNAL_LABEL}.
+For example,
+
+@example
+fprintf (@var{stream}, "\t.word L%d\n", @var{value})
+@end example
+
+@findex ASM_OUTPUT_CASE_LABEL
+@item ASM_OUTPUT_CASE_LABEL (@var{stream}, @var{prefix}, @var{num}, @var{table})
+Define this if the label before a jump-table needs to be output
+specially.  The first three arguments are the same as for
+@code{ASM_OUTPUT_INTERNAL_LABEL}; the fourth argument is the
+jump-table which follows (a @code{jump_insn} containing an
+@code{addr_vec} or @code{addr_diff_vec}).
+
+This feature is used on system V to output a @code{swbeg} statement
+for the table.
+
+If this macro is not defined, these labels are output with
+@code{ASM_OUTPUT_INTERNAL_LABEL}.
+
+@findex ASM_OUTPUT_CASE_END
+@item ASM_OUTPUT_CASE_END (@var{stream}, @var{num}, @var{table})
+Define this if something special must be output at the end of a
+jump-table.  The definition should be a C statement to be executed
+after the assembler code for the table is written.  It should write
+the appropriate code to stdio stream @var{stream}.  The argument
+@var{table} is the jump-table insn, and @var{num} is the label-number
+of the preceding label.
+
+If this macro is not defined, nothing special is output at the end of
+the jump-table.
+@end table
+
+@node Exception Region Output
+@subsection Assembler Commands for Exception Regions
+
+@c prevent bad page break with this line
+
+This describes commands marking the start and the end of an exception
+region.
+
+@table @code
+@findex EH_FRAME_SECTION_NAME
+@item EH_FRAME_SECTION_NAME
+If defined, a C string constant for the name of the section containing
+exception handling frame unwind information.  If not defined, GCC will
+provide a default definition if the target supports named sections.
+@file{crtstuff.c} uses this macro to switch to the appropriate section.
+
+You should define this symbol if your target supports DWARF 2 frame
+unwind information and the default definition does not work.
+
+@findex EH_FRAME_IN_DATA_SECTION
+@item EH_FRAME_IN_DATA_SECTION
+If defined, DWARF 2 frame unwind information will be placed in the
+data section even though the target supports named sections.  This
+might be necessary, for instance, if the system linker does garbage
+collection and sections cannot be marked as not to be collected.
+
+Do not define this macro unless @code{TARGET_ASM_NAMED_SECTION} is
+also defined.
+
+@findex MASK_RETURN_ADDR
+@item MASK_RETURN_ADDR
+An rtx used to mask the return address found via @code{RETURN_ADDR_RTX}, so
+that it does not contain any extraneous set bits in it.
+
+@findex DWARF2_UNWIND_INFO
+@item DWARF2_UNWIND_INFO
+Define this macro to 0 if your target supports DWARF 2 frame unwind
+information, but it does not yet work with exception handling.
+Otherwise, if your target supports this information (if it defines
+@samp{INCOMING_RETURN_ADDR_RTX} and either @samp{UNALIGNED_INT_ASM_OP}
+or @samp{OBJECT_FORMAT_ELF}), GCC will provide a default definition of
+1.
+
+If this macro is defined to 1, the DWARF 2 unwinder will be the default
+exception handling mechanism; otherwise, @code{setjmp}/@code{longjmp} will be used by
+default.
+
+If this macro is defined to anything, the DWARF 2 unwinder will be used
+instead of inline unwinders and @code{__unwind_function} in the non-@code{setjmp} case.
+
+@findex DWARF_CIE_DATA_ALIGNMENT
+@item DWARF_CIE_DATA_ALIGNMENT
+This macro need only be defined if the target might save registers in the
+function prologue at an offset to the stack pointer that is not aligned to
+@code{UNITS_PER_WORD}.  The definition should be the negative minimum
+alignment if @code{STACK_GROWS_DOWNWARD} is defined, and the positive
+minimum alignment otherwise.  @xref{SDB and DWARF}.  Only applicable if
+the target supports DWARF 2 frame unwind information.
+
+@end table
+
+@deftypefn {Target Hook} void TARGET_ASM_EXCEPTION_SECTION ()
+If defined, a function that switches to the section in which the main
+exception table is to be placed (@pxref{Sections}).  The default is a
+function that switches to a section named @code{.gcc_except_table} on
+machines that support named sections via
+@code{TARGET_ASM_NAMED_SECTION}, otherwise if @option{-fpic} or
+@option{-fPIC} is in effect, the @code{data_section}, otherwise the
+@code{readonly_data_section}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_ASM_EH_FRAME_SECTION ()
+If defined, a function that switches to the section in which the DWARF 2
+frame unwind information to be placed (@pxref{Sections}).  The default
+is a function that outputs a standard GAS section directive, if
+@code{EH_FRAME_SECTION_NAME} is defined, or else a data section
+directive followed by a synthetic label.
+@end deftypefn
+
+@node Alignment Output
+@subsection Assembler Commands for Alignment
+
+@c prevent bad page break with this line
+This describes commands for alignment.
+
+@table @code
+@findex JUMP_ALIGN
+@item JUMP_ALIGN (@var{label})
+The alignment (log base 2) to put in front of @var{label}, which is
+a common destination of jumps and has no fallthru incoming edge.
+
+This macro need not be defined if you don't want any special alignment
+to be done at such a time.  Most machine descriptions do not currently
+define the macro.
+
+Unless it's necessary to inspect the @var{label} parameter, it is better
+to set the variable @var{align_jumps} in the target's
+@code{OVERRIDE_OPTIONS}.  Otherwise, you should try to honor the user's
+selection in @var{align_jumps} in a @code{JUMP_ALIGN} implementation.
+
+@findex LABEL_ALIGN_AFTER_BARRIER
+@item LABEL_ALIGN_AFTER_BARRIER (@var{label})
+The alignment (log base 2) to put in front of @var{label}, which follows
+a @code{BARRIER}.
+
+This macro need not be defined if you don't want any special alignment
+to be done at such a time.  Most machine descriptions do not currently
+define the macro.
+
+@findex LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP
+@item LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP
+The maximum number of bytes to skip when applying
+@code{LABEL_ALIGN_AFTER_BARRIER}.  This works only if
+@code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.
+
+@findex LOOP_ALIGN
+@item LOOP_ALIGN (@var{label})
+The alignment (log base 2) to put in front of @var{label}, which follows
+a @code{NOTE_INSN_LOOP_BEG} note.
+
+This macro need not be defined if you don't want any special alignment
+to be done at such a time.  Most machine descriptions do not currently
+define the macro.
+
+Unless it's necessary to inspect the @var{label} parameter, it is better
+to set the variable @code{align_loops} in the target's
+@code{OVERRIDE_OPTIONS}.  Otherwise, you should try to honor the user's
+selection in @code{align_loops} in a @code{LOOP_ALIGN} implementation.
+
+@findex LOOP_ALIGN_MAX_SKIP
+@item LOOP_ALIGN_MAX_SKIP
+The maximum number of bytes to skip when applying @code{LOOP_ALIGN}.
+This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.
+
+@findex LABEL_ALIGN
+@item LABEL_ALIGN (@var{label})
+The alignment (log base 2) to put in front of @var{label}.
+If @code{LABEL_ALIGN_AFTER_BARRIER} / @code{LOOP_ALIGN} specify a different alignment,
+the maximum of the specified values is used.
+
+Unless it's necessary to inspect the @var{label} parameter, it is better
+to set the variable @code{align_labels} in the target's
+@code{OVERRIDE_OPTIONS}.  Otherwise, you should try to honor the user's
+selection in @code{align_labels} in a @code{LABEL_ALIGN} implementation.
+
+@findex LABEL_ALIGN_MAX_SKIP
+@item LABEL_ALIGN_MAX_SKIP
+The maximum number of bytes to skip when applying @code{LABEL_ALIGN}.
+This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.
+
+@findex ASM_OUTPUT_SKIP
+@item ASM_OUTPUT_SKIP (@var{stream}, @var{nbytes})
+A C statement to output to the stdio stream @var{stream} an assembler
+instruction to advance the location counter by @var{nbytes} bytes.
+Those bytes should be zero when loaded.  @var{nbytes} will be a C
+expression of type @code{int}.
+
+@findex ASM_NO_SKIP_IN_TEXT
+@item ASM_NO_SKIP_IN_TEXT
+Define this macro if @code{ASM_OUTPUT_SKIP} should not be used in the
+text section because it fails to put zeros in the bytes that are skipped.
+This is true on many Unix systems, where the pseudo--op to skip bytes
+produces no-op instructions rather than zeros when used in the text
+section.
+
+@findex ASM_OUTPUT_ALIGN
+@item ASM_OUTPUT_ALIGN (@var{stream}, @var{power})
+A C statement to output to the stdio stream @var{stream} an assembler
+command to advance the location counter to a multiple of 2 to the
+@var{power} bytes.  @var{power} will be a C expression of type @code{int}.
+
+@findex ASM_OUTPUT_MAX_SKIP_ALIGN
+@item ASM_OUTPUT_MAX_SKIP_ALIGN (@var{stream}, @var{power}, @var{max_skip})
+A C statement to output to the stdio stream @var{stream} an assembler
+command to advance the location counter to a multiple of 2 to the
+@var{power} bytes, but only if @var{max_skip} or fewer bytes are needed to
+satisfy the alignment request.  @var{power} and @var{max_skip} will be
+a C expression of type @code{int}.
+@end table
+
+@need 3000
+@node Debugging Info
+@section Controlling Debugging Information Format
+
+@c prevent bad page break with this line
+This describes how to specify debugging information.
+
+@menu
+* All Debuggers::      Macros that affect all debugging formats uniformly.
+* DBX Options::        Macros enabling specific options in DBX format.
+* DBX Hooks::          Hook macros for varying DBX format.
+* File Names and DBX:: Macros controlling output of file names in DBX format.
+* SDB and DWARF::      Macros for SDB (COFF) and DWARF formats.
+* VMS Debug::          Macros for VMS debug format.
+@end menu
+
+@node All Debuggers
+@subsection Macros Affecting All Debugging Formats
+
+@c prevent bad page break with this line
+These macros affect all debugging formats.
+
+@table @code
+@findex DBX_REGISTER_NUMBER
+@item DBX_REGISTER_NUMBER (@var{regno})
+A C expression that returns the DBX register number for the compiler
+register number @var{regno}.  In the default macro provided, the value
+of this expression will be @var{regno} itself.  But sometimes there are
+some registers that the compiler knows about and DBX does not, or vice
+versa.  In such cases, some register may need to have one number in the
+compiler and another for DBX@.
+
+If two registers have consecutive numbers inside GCC, and they can be
+used as a pair to hold a multiword value, then they @emph{must} have
+consecutive numbers after renumbering with @code{DBX_REGISTER_NUMBER}.
+Otherwise, debuggers will be unable to access such a pair, because they
+expect register pairs to be consecutive in their own numbering scheme.
+
+If you find yourself defining @code{DBX_REGISTER_NUMBER} in way that
+does not preserve register pairs, then what you must do instead is
+redefine the actual register numbering scheme.
+
+@findex DEBUGGER_AUTO_OFFSET
+@item DEBUGGER_AUTO_OFFSET (@var{x})
+A C expression that returns the integer offset value for an automatic
+variable having address @var{x} (an RTL expression).  The default
+computation assumes that @var{x} is based on the frame-pointer and
+gives the offset from the frame-pointer.  This is required for targets
+that produce debugging output for DBX or COFF-style debugging output
+for SDB and allow the frame-pointer to be eliminated when the
+@option{-g} options is used.
+
+@findex DEBUGGER_ARG_OFFSET
+@item DEBUGGER_ARG_OFFSET (@var{offset}, @var{x})
+A C expression that returns the integer offset value for an argument
+having address @var{x} (an RTL expression).  The nominal offset is
+@var{offset}.
+
+@findex PREFERRED_DEBUGGING_TYPE
+@item PREFERRED_DEBUGGING_TYPE
+A C expression that returns the type of debugging output GCC should
+produce when the user specifies just @option{-g}.  Define
+this if you have arranged for GCC to support more than one format of
+debugging output.  Currently, the allowable values are @code{DBX_DEBUG},
+@code{SDB_DEBUG}, @code{DWARF_DEBUG}, @code{DWARF2_DEBUG},
+@code{XCOFF_DEBUG}, @code{VMS_DEBUG}, and @code{VMS_AND_DWARF2_DEBUG}.
+
+When the user specifies @option{-ggdb}, GCC normally also uses the
+value of this macro to select the debugging output format, but with two
+exceptions.  If @code{DWARF2_DEBUGGING_INFO} is defined and
+@code{LINKER_DOES_NOT_WORK_WITH_DWARF2} is not defined, GCC uses the
+value @code{DWARF2_DEBUG}.  Otherwise, if @code{DBX_DEBUGGING_INFO} is
+defined, GCC uses @code{DBX_DEBUG}.
+
+The value of this macro only affects the default debugging output; the
+user can always get a specific type of output by using @option{-gstabs},
+@option{-gcoff}, @option{-gdwarf-1}, @option{-gdwarf-2}, @option{-gxcoff},
+or @option{-gvms}.
+@end table
+
+@node DBX Options
+@subsection Specific Options for DBX Output
+
+@c prevent bad page break with this line
+These are specific options for DBX output.
+
+@table @code
+@findex DBX_DEBUGGING_INFO
+@item DBX_DEBUGGING_INFO
+Define this macro if GCC should produce debugging output for DBX
+in response to the @option{-g} option.
+
+@findex XCOFF_DEBUGGING_INFO
+@item XCOFF_DEBUGGING_INFO
+Define this macro if GCC should produce XCOFF format debugging output
+in response to the @option{-g} option.  This is a variant of DBX format.
+
+@findex DEFAULT_GDB_EXTENSIONS
+@item DEFAULT_GDB_EXTENSIONS
+Define this macro to control whether GCC should by default generate
+GDB's extended version of DBX debugging information (assuming DBX-format
+debugging information is enabled at all).  If you don't define the
+macro, the default is 1: always generate the extended information
+if there is any occasion to.
+
+@findex DEBUG_SYMS_TEXT
+@item DEBUG_SYMS_TEXT
+Define this macro if all @code{.stabs} commands should be output while
+in the text section.
+
+@findex ASM_STABS_OP
+@item ASM_STABS_OP
+A C string constant, including spacing, naming the assembler pseudo op to
+use instead of @code{"\t.stabs\t"} to define an ordinary debugging symbol.
+If you don't define this macro, @code{"\t.stabs\t"} is used.  This macro
+applies only to DBX debugging information format.
+
+@findex ASM_STABD_OP
+@item ASM_STABD_OP
+A C string constant, including spacing, naming the assembler pseudo op to
+use instead of @code{"\t.stabd\t"} to define a debugging symbol whose
+value is the current location.  If you don't define this macro,
+@code{"\t.stabd\t"} is used.  This macro applies only to DBX debugging
+information format.
+
+@findex ASM_STABN_OP
+@item ASM_STABN_OP
+A C string constant, including spacing, naming the assembler pseudo op to
+use instead of @code{"\t.stabn\t"} to define a debugging symbol with no
+name.  If you don't define this macro, @code{"\t.stabn\t"} is used.  This
+macro applies only to DBX debugging information format.
+
+@findex DBX_NO_XREFS
+@item DBX_NO_XREFS
+Define this macro if DBX on your system does not support the construct
+@samp{xs@var{tagname}}.  On some systems, this construct is used to
+describe a forward reference to a structure named @var{tagname}.
+On other systems, this construct is not supported at all.
+
+@findex DBX_CONTIN_LENGTH
+@item DBX_CONTIN_LENGTH
+A symbol name in DBX-format debugging information is normally
+continued (split into two separate @code{.stabs} directives) when it
+exceeds a certain length (by default, 80 characters).  On some
+operating systems, DBX requires this splitting; on others, splitting
+must not be done.  You can inhibit splitting by defining this macro
+with the value zero.  You can override the default splitting-length by
+defining this macro as an expression for the length you desire.
+
+@findex DBX_CONTIN_CHAR
+@item DBX_CONTIN_CHAR
+Normally continuation is indicated by adding a @samp{\} character to
+the end of a @code{.stabs} string when a continuation follows.  To use
+a different character instead, define this macro as a character
+constant for the character you want to use.  Do not define this macro
+if backslash is correct for your system.
+
+@findex DBX_STATIC_STAB_DATA_SECTION
+@item DBX_STATIC_STAB_DATA_SECTION
+Define this macro if it is necessary to go to the data section before
+outputting the @samp{.stabs} pseudo-op for a non-global static
+variable.
+
+@findex DBX_TYPE_DECL_STABS_CODE
+@item DBX_TYPE_DECL_STABS_CODE
+The value to use in the ``code'' field of the @code{.stabs} directive
+for a typedef.  The default is @code{N_LSYM}.
+
+@findex DBX_STATIC_CONST_VAR_CODE
+@item DBX_STATIC_CONST_VAR_CODE
+The value to use in the ``code'' field of the @code{.stabs} directive
+for a static variable located in the text section.  DBX format does not
+provide any ``right'' way to do this.  The default is @code{N_FUN}.
+
+@findex DBX_REGPARM_STABS_CODE
+@item DBX_REGPARM_STABS_CODE
+The value to use in the ``code'' field of the @code{.stabs} directive
+for a parameter passed in registers.  DBX format does not provide any
+``right'' way to do this.  The default is @code{N_RSYM}.
+
+@findex DBX_REGPARM_STABS_LETTER
+@item DBX_REGPARM_STABS_LETTER
+The letter to use in DBX symbol data to identify a symbol as a parameter
+passed in registers.  DBX format does not customarily provide any way to
+do this.  The default is @code{'P'}.
+
+@findex DBX_MEMPARM_STABS_LETTER
+@item DBX_MEMPARM_STABS_LETTER
+The letter to use in DBX symbol data to identify a symbol as a stack
+parameter.  The default is @code{'p'}.
+
+@findex DBX_FUNCTION_FIRST
+@item DBX_FUNCTION_FIRST
+Define this macro if the DBX information for a function and its
+arguments should precede the assembler code for the function.  Normally,
+in DBX format, the debugging information entirely follows the assembler
+code.
+
+@findex DBX_LBRAC_FIRST
+@item DBX_LBRAC_FIRST
+Define this macro if the @code{N_LBRAC} symbol for a block should
+precede the debugging information for variables and functions defined in
+that block.  Normally, in DBX format, the @code{N_LBRAC} symbol comes
+first.
+
+@findex DBX_BLOCKS_FUNCTION_RELATIVE
+@item DBX_BLOCKS_FUNCTION_RELATIVE
+Define this macro if the value of a symbol describing the scope of a
+block (@code{N_LBRAC} or @code{N_RBRAC}) should be relative to the start
+of the enclosing function.  Normally, GCC uses an absolute address.
+
+@findex DBX_USE_BINCL
+@item DBX_USE_BINCL
+Define this macro if GCC should generate @code{N_BINCL} and
+@code{N_EINCL} stabs for included header files, as on Sun systems.  This
+macro also directs GCC to output a type number as a pair of a file
+number and a type number within the file.  Normally, GCC does not
+generate @code{N_BINCL} or @code{N_EINCL} stabs, and it outputs a single
+number for a type number.
+@end table
+
+@node DBX Hooks
+@subsection Open-Ended Hooks for DBX Format
+
+@c prevent bad page break with this line
+These are hooks for DBX format.
+
+@table @code
+@findex DBX_OUTPUT_LBRAC
+@item DBX_OUTPUT_LBRAC (@var{stream}, @var{name})
+Define this macro to say how to output to @var{stream} the debugging
+information for the start of a scope level for variable names.  The
+argument @var{name} is the name of an assembler symbol (for use with
+@code{assemble_name}) whose value is the address where the scope begins.
+
+@findex DBX_OUTPUT_RBRAC
+@item DBX_OUTPUT_RBRAC (@var{stream}, @var{name})
+Like @code{DBX_OUTPUT_LBRAC}, but for the end of a scope level.
+
+@findex DBX_OUTPUT_ENUM
+@item DBX_OUTPUT_ENUM (@var{stream}, @var{type})
+Define this macro if the target machine requires special handling to
+output an enumeration type.  The definition should be a C statement
+(sans semicolon) to output the appropriate information to @var{stream}
+for the type @var{type}.
+
+@findex DBX_OUTPUT_FUNCTION_END
+@item DBX_OUTPUT_FUNCTION_END (@var{stream}, @var{function})
+Define this macro if the target machine requires special output at the
+end of the debugging information for a function.  The definition should
+be a C statement (sans semicolon) to output the appropriate information
+to @var{stream}.  @var{function} is the @code{FUNCTION_DECL} node for
+the function.
+
+@findex DBX_OUTPUT_STANDARD_TYPES
+@item DBX_OUTPUT_STANDARD_TYPES (@var{syms})
+Define this macro if you need to control the order of output of the
+standard data types at the beginning of compilation.  The argument
+@var{syms} is a @code{tree} which is a chain of all the predefined
+global symbols, including names of data types.
+
+Normally, DBX output starts with definitions of the types for integers
+and characters, followed by all the other predefined types of the
+particular language in no particular order.
+
+On some machines, it is necessary to output different particular types
+first.  To do this, define @code{DBX_OUTPUT_STANDARD_TYPES} to output
+those symbols in the necessary order.  Any predefined types that you
+don't explicitly output will be output afterward in no particular order.
+
+Be careful not to define this macro so that it works only for C@.  There
+are no global variables to access most of the built-in types, because
+another language may have another set of types.  The way to output a
+particular type is to look through @var{syms} to see if you can find it.
+Here is an example:
+
+@smallexample
+@{
+  tree decl;
+  for (decl = syms; decl; decl = TREE_CHAIN (decl))
+    if (!strcmp (IDENTIFIER_POINTER (DECL_NAME (decl)),
+                 "long int"))
+      dbxout_symbol (decl);
+  @dots{}
+@}
+@end smallexample
+
+@noindent
+This does nothing if the expected type does not exist.
+
+See the function @code{init_decl_processing} in @file{c-decl.c} to find
+the names to use for all the built-in C types.
+
+Here is another way of finding a particular type:
+
+@c this is still overfull.  --mew 10feb93
+@smallexample
+@{
+  tree decl;
+  for (decl = syms; decl; decl = TREE_CHAIN (decl))
+    if (TREE_CODE (decl) == TYPE_DECL
+        && (TREE_CODE (TREE_TYPE (decl))
+            == INTEGER_CST)
+        && TYPE_PRECISION (TREE_TYPE (decl)) == 16
+        && TYPE_UNSIGNED (TREE_TYPE (decl)))
+@group
+      /* @r{This must be @code{unsigned short}.}  */
+      dbxout_symbol (decl);
+  @dots{}
+@}
+@end group
+@end smallexample
+
+@findex NO_DBX_FUNCTION_END
+@item NO_DBX_FUNCTION_END
+Some stabs encapsulation formats (in particular ECOFF), cannot handle the
+@code{.stabs "",N_FUN,,0,0,Lscope-function-1} gdb dbx extension construct.
+On those machines, define this macro to turn this feature off without
+disturbing the rest of the gdb extensions.
+
+@end table
+
+@node File Names and DBX
+@subsection File Names in DBX Format
+
+@c prevent bad page break with this line
+This describes file names in DBX format.
+
+@table @code
+@findex DBX_WORKING_DIRECTORY
+@item DBX_WORKING_DIRECTORY
+Define this if DBX wants to have the current directory recorded in each
+object file.
+
+Note that the working directory is always recorded if GDB extensions are
+enabled.
+
+@findex DBX_OUTPUT_MAIN_SOURCE_FILENAME
+@item DBX_OUTPUT_MAIN_SOURCE_FILENAME (@var{stream}, @var{name})
+A C statement to output DBX debugging information to the stdio stream
+@var{stream} which indicates that file @var{name} is the main source
+file---the file specified as the input file for compilation.
+This macro is called only once, at the beginning of compilation.
+
+This macro need not be defined if the standard form of output
+for DBX debugging information is appropriate.
+
+@findex DBX_OUTPUT_MAIN_SOURCE_DIRECTORY
+@item DBX_OUTPUT_MAIN_SOURCE_DIRECTORY (@var{stream}, @var{name})
+A C statement to output DBX debugging information to the stdio stream
+@var{stream} which indicates that the current directory during
+compilation is named @var{name}.
+
+This macro need not be defined if the standard form of output
+for DBX debugging information is appropriate.
+
+@findex DBX_OUTPUT_MAIN_SOURCE_FILE_END
+@item DBX_OUTPUT_MAIN_SOURCE_FILE_END (@var{stream}, @var{name})
+A C statement to output DBX debugging information at the end of
+compilation of the main source file @var{name}.
+
+If you don't define this macro, nothing special is output at the end
+of compilation, which is correct for most machines.
+
+@findex DBX_OUTPUT_SOURCE_FILENAME
+@item DBX_OUTPUT_SOURCE_FILENAME (@var{stream}, @var{name})
+A C statement to output DBX debugging information to the stdio stream
+@var{stream} which indicates that file @var{name} is the current source
+file.  This output is generated each time input shifts to a different
+source file as a result of @samp{#include}, the end of an included file,
+or a @samp{#line} command.
+
+This macro need not be defined if the standard form of output
+for DBX debugging information is appropriate.
+@end table
+
+@need 2000
+@node SDB and DWARF
+@subsection Macros for SDB and DWARF Output
+
+@c prevent bad page break with this line
+Here are macros for SDB and DWARF output.
+
+@table @code
+@findex SDB_DEBUGGING_INFO
+@item SDB_DEBUGGING_INFO
+Define this macro if GCC should produce COFF-style debugging output
+for SDB in response to the @option{-g} option.
+
+@findex DWARF_DEBUGGING_INFO
+@item DWARF_DEBUGGING_INFO
+Define this macro if GCC should produce dwarf format debugging output
+in response to the @option{-g} option.
+
+@findex DWARF2_DEBUGGING_INFO
+@item DWARF2_DEBUGGING_INFO
+Define this macro if GCC should produce dwarf version 2 format
+debugging output in response to the @option{-g} option.
+
+To support optional call frame debugging information, you must also
+define @code{INCOMING_RETURN_ADDR_RTX} and either set
+@code{RTX_FRAME_RELATED_P} on the prologue insns if you use RTL for the
+prologue, or call @code{dwarf2out_def_cfa} and @code{dwarf2out_reg_save}
+as appropriate from @code{TARGET_ASM_FUNCTION_PROLOGUE} if you don't.
+
+@findex DWARF2_FRAME_INFO
+@item DWARF2_FRAME_INFO
+Define this macro to a nonzero value if GCC should always output
+Dwarf 2 frame information.  If @code{DWARF2_UNWIND_INFO}
+(@pxref{Exception Region Output} is nonzero, GCC will output this
+information not matter how you define @code{DWARF2_FRAME_INFO}.
+
+@findex LINKER_DOES_NOT_WORK_WITH_DWARF2
+@item LINKER_DOES_NOT_WORK_WITH_DWARF2
+Define this macro if the linker does not work with Dwarf version 2.
+Normally, if the user specifies only @option{-ggdb} GCC will use Dwarf
+version 2 if available; this macro disables this.  See the description
+of the @code{PREFERRED_DEBUGGING_TYPE} macro for more details.
+
+@findex DWARF2_GENERATE_TEXT_SECTION_LABEL
+@item DWARF2_GENERATE_TEXT_SECTION_LABEL
+By default, the Dwarf 2 debugging information generator will generate a
+label to mark the beginning of the text section.  If it is better simply
+to use the name of the text section itself, rather than an explicit label,
+to indicate the beginning of the text section, define this macro to zero.
+
+@findex DWARF2_ASM_LINE_DEBUG_INFO
+@item DWARF2_ASM_LINE_DEBUG_INFO
+Define this macro to be a nonzero value if the assembler can generate Dwarf 2
+line debug info sections.  This will result in much more compact line number
+tables, and hence is desirable if it works.
+
+@findex PUT_SDB_@dots{}
+@item PUT_SDB_@dots{}
+Define these macros to override the assembler syntax for the special
+SDB assembler directives.  See @file{sdbout.c} for a list of these
+macros and their arguments.  If the standard syntax is used, you need
+not define them yourself.
+
+@findex SDB_DELIM
+@item SDB_DELIM
+Some assemblers do not support a semicolon as a delimiter, even between
+SDB assembler directives.  In that case, define this macro to be the
+delimiter to use (usually @samp{\n}).  It is not necessary to define
+a new set of @code{PUT_SDB_@var{op}} macros if this is the only change
+required.
+
+@findex SDB_GENERATE_FAKE
+@item SDB_GENERATE_FAKE
+Define this macro to override the usual method of constructing a dummy
+name for anonymous structure and union types.  See @file{sdbout.c} for
+more information.
+
+@findex SDB_ALLOW_UNKNOWN_REFERENCES
+@item SDB_ALLOW_UNKNOWN_REFERENCES
+Define this macro to allow references to unknown structure,
+union, or enumeration tags to be emitted.  Standard COFF does not
+allow handling of unknown references, MIPS ECOFF has support for
+it.
+
+@findex SDB_ALLOW_FORWARD_REFERENCES
+@item SDB_ALLOW_FORWARD_REFERENCES
+Define this macro to allow references to structure, union, or
+enumeration tags that have not yet been seen to be handled.  Some
+assemblers choke if forward tags are used, while some require it.
+@end table
+
+@need 2000
+@node VMS Debug
+@subsection Macros for VMS Debug Format
+
+@c prevent bad page break with this line
+Here are macros for VMS debug format.
+
+@table @code
+@findex VMS_DEBUGGING_INFO
+@item VMS_DEBUGGING_INFO
+Define this macro if GCC should produce debugging output for VMS
+in response to the @option{-g} option.  The default behavior for VMS
+is to generate minimal debug info for a traceback in the absence of
+@option{-g} unless explicitly overridden with @option{-g0}.  This
+behavior is controlled by @code{OPTIMIZATION_OPTIONS} and
+@code{OVERRIDE_OPTIONS}.
+@end table
+
+@node Cross-compilation
+@section Cross Compilation and Floating Point
+@cindex cross compilation and floating point
+@cindex floating point and cross compilation
+
+While all modern machines use 2's complement representation for integers,
+there are a variety of representations for floating point numbers.  This
+means that in a cross-compiler the representation of floating point numbers
+in the compiled program may be different from that used in the machine
+doing the compilation.
+
+@findex atof
+Because different representation systems may offer different amounts of
+range and precision, the cross compiler cannot safely use the host
+machine's floating point arithmetic.  Therefore, floating point constants
+must be represented in the target machine's format.  This means that the
+cross compiler cannot use @code{atof} to parse a floating point constant;
+it must have its own special routine to use instead.  Also, constant
+folding must emulate the target machine's arithmetic (or must not be done
+at all).
+
+The macros in the following table should be defined only if you are cross
+compiling between different floating point formats.
+
+Otherwise, don't define them.  Then default definitions will be set up which
+use @code{double} as the data type, @code{==} to test for equality, etc.
+
+You don't need to worry about how many times you use an operand of any
+of these macros.  The compiler never uses operands which have side effects.
+
+@table @code
+@findex REAL_VALUE_TYPE
+@item REAL_VALUE_TYPE
+A macro for the C data type to be used to hold a floating point value
+in the target machine's format.  Typically this would be a
+@code{struct} containing an array of @code{int}.
+
+@findex REAL_VALUES_EQUAL
+@item REAL_VALUES_EQUAL (@var{x}, @var{y})
+A macro for a C expression which compares for equality the two values,
+@var{x} and @var{y}, both of type @code{REAL_VALUE_TYPE}.
+
+@findex REAL_VALUES_LESS
+@item REAL_VALUES_LESS (@var{x}, @var{y})
+A macro for a C expression which tests whether @var{x} is less than
+@var{y}, both values being of type @code{REAL_VALUE_TYPE} and
+interpreted as floating point numbers in the target machine's
+representation.
+
+@findex REAL_VALUE_LDEXP
+@findex ldexp
+@item REAL_VALUE_LDEXP (@var{x}, @var{scale})
+A macro for a C expression which performs the standard library
+function @code{ldexp}, but using the target machine's floating point
+representation.  Both @var{x} and the value of the expression have
+type @code{REAL_VALUE_TYPE}.  The second argument, @var{scale}, is an
+integer.
+
+@findex REAL_VALUE_FIX
+@item REAL_VALUE_FIX (@var{x})
+A macro whose definition is a C expression to convert the target-machine
+floating point value @var{x} to a signed integer.  @var{x} has type
+@code{REAL_VALUE_TYPE}.
+
+@findex REAL_VALUE_UNSIGNED_FIX
+@item REAL_VALUE_UNSIGNED_FIX (@var{x})
+A macro whose definition is a C expression to convert the target-machine
+floating point value @var{x} to an unsigned integer.  @var{x} has type
+@code{REAL_VALUE_TYPE}.
+
+@findex REAL_VALUE_RNDZINT
+@item REAL_VALUE_RNDZINT (@var{x})
+A macro whose definition is a C expression to round the target-machine
+floating point value @var{x} towards zero to an integer value (but still
+as a floating point number).  @var{x} has type @code{REAL_VALUE_TYPE},
+and so does the value.
+
+@findex REAL_VALUE_UNSIGNED_RNDZINT
+@item REAL_VALUE_UNSIGNED_RNDZINT (@var{x})
+A macro whose definition is a C expression to round the target-machine
+floating point value @var{x} towards zero to an unsigned integer value
+(but still represented as a floating point number).  @var{x} has type
+@code{REAL_VALUE_TYPE}, and so does the value.
+
+@findex REAL_VALUE_ATOF
+@item REAL_VALUE_ATOF (@var{string}, @var{mode})
+A macro for a C expression which converts @var{string}, an expression of
+type @code{char *}, into a floating point number in the target machine's
+representation for mode @var{mode}.  The value has type
+@code{REAL_VALUE_TYPE}.
+
+@findex REAL_INFINITY
+@item REAL_INFINITY
+Define this macro if infinity is a possible floating point value, and
+therefore division by 0 is legitimate.
+
+@findex REAL_VALUE_ISINF
+@findex isinf
+@item REAL_VALUE_ISINF (@var{x})
+A macro for a C expression which determines whether @var{x}, a floating
+point value, is infinity.  The value has type @code{int}.
+By default, this is defined to call @code{isinf}.
+
+@findex REAL_VALUE_ISNAN
+@findex isnan
+@item REAL_VALUE_ISNAN (@var{x})
+A macro for a C expression which determines whether @var{x}, a floating
+point value, is a ``nan'' (not-a-number).  The value has type
+@code{int}.  By default, this is defined to call @code{isnan}.
+@end table
+
+@cindex constant folding and floating point
+Define the following additional macros if you want to make floating
+point constant folding work while cross compiling.  If you don't
+define them, cross compilation is still possible, but constant folding
+will not happen for floating point values.
+
+@table @code
+@findex REAL_ARITHMETIC
+@item REAL_ARITHMETIC (@var{output}, @var{code}, @var{x}, @var{y})
+A macro for a C statement which calculates an arithmetic operation of
+the two floating point values @var{x} and @var{y}, both of type
+@code{REAL_VALUE_TYPE} in the target machine's representation, to
+produce a result of the same type and representation which is stored
+in @var{output} (which will be a variable).
+
+The operation to be performed is specified by @var{code}, a tree code
+which will always be one of the following: @code{PLUS_EXPR},
+@code{MINUS_EXPR}, @code{MULT_EXPR}, @code{RDIV_EXPR},
+@code{MAX_EXPR}, @code{MIN_EXPR}.
+
+@cindex overflow while constant folding
+The expansion of this macro is responsible for checking for overflow.
+If overflow happens, the macro expansion should execute the statement
+@code{return 0;}, which indicates the inability to perform the
+arithmetic operation requested.
+
+@findex REAL_VALUE_NEGATE
+@item REAL_VALUE_NEGATE (@var{x})
+A macro for a C expression which returns the negative of the floating
+point value @var{x}.  Both @var{x} and the value of the expression
+have type @code{REAL_VALUE_TYPE} and are in the target machine's
+floating point representation.
+
+There is no way for this macro to report overflow, since overflow
+can't happen in the negation operation.
+
+@findex REAL_VALUE_TRUNCATE
+@item REAL_VALUE_TRUNCATE (@var{mode}, @var{x})
+A macro for a C expression which converts the floating point value
+@var{x} to mode @var{mode}.
+
+Both @var{x} and the value of the expression are in the target machine's
+floating point representation and have type @code{REAL_VALUE_TYPE}.
+However, the value should have an appropriate bit pattern to be output
+properly as a floating constant whose precision accords with mode
+@var{mode}.
+
+There is no way for this macro to report overflow.
+
+@findex REAL_VALUE_TO_INT
+@item REAL_VALUE_TO_INT (@var{low}, @var{high}, @var{x})
+A macro for a C expression which converts a floating point value
+@var{x} into a double-precision integer which is then stored into
+@var{low} and @var{high}, two variables of type @var{int}.
+
+@item REAL_VALUE_FROM_INT (@var{x}, @var{low}, @var{high}, @var{mode})
+@findex REAL_VALUE_FROM_INT
+A macro for a C expression which converts a double-precision integer
+found in @var{low} and @var{high}, two variables of type @var{int},
+into a floating point value which is then stored into @var{x}.
+The value is in the target machine's representation for mode @var{mode}
+and has the type @code{REAL_VALUE_TYPE}.
+@end table
+
+@node Mode Switching
+@section Mode Switching Instructions
+@cindex mode switching
+The following macros control mode switching optimizations:
+
+@table @code
+@findex OPTIMIZE_MODE_SWITCHING
+@item OPTIMIZE_MODE_SWITCHING (@var{entity})
+Define this macro if the port needs extra instructions inserted for mode
+switching in an optimizing compilation.
+
+For an example, the SH4 can perform both single and double precision
+floating point operations, but to perform a single precision operation,
+the FPSCR PR bit has to be cleared, while for a double precision
+operation, this bit has to be set.  Changing the PR bit requires a general
+purpose register as a scratch register, hence these FPSCR sets have to
+be inserted before reload, i.e.@: you can't put this into instruction emitting
+or @code{MACHINE_DEPENDENT_REORG}.
+
+You can have multiple entities that are mode-switched, and select at run time
+which entities actually need it.  @code{OPTIMIZE_MODE_SWITCHING} should
+return nonzero for any @var{entity} that needs mode-switching.
+If you define this macro, you also have to define
+@code{NUM_MODES_FOR_MODE_SWITCHING}, @code{MODE_NEEDED},
+@code{MODE_PRIORITY_TO_MODE} and @code{EMIT_MODE_SET}.
+@code{NORMAL_MODE} is optional.
+
+@findex NUM_MODES_FOR_MODE_SWITCHING
+@item NUM_MODES_FOR_MODE_SWITCHING
+If you define @code{OPTIMIZE_MODE_SWITCHING}, you have to define this as
+initializer for an array of integers.  Each initializer element
+N refers to an entity that needs mode switching, and specifies the number
+of different modes that might need to be set for this entity.
+The position of the initializer in the initializer - starting counting at
+zero - determines the integer that is used to refer to the mode-switched
+entity in question.
+In macros that take mode arguments / yield a mode result, modes are
+represented as numbers 0 @dots{} N @minus{} 1.  N is used to specify that no mode
+switch is needed / supplied.
+
+@findex MODE_NEEDED
+@item MODE_NEEDED (@var{entity}, @var{insn})
+@var{entity} is an integer specifying a mode-switched entity.  If
+@code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this macro to
+return an integer value not larger than the corresponding element in
+@code{NUM_MODES_FOR_MODE_SWITCHING}, to denote the mode that @var{entity} must
+be switched into prior to the execution of @var{insn}.
+
+@findex NORMAL_MODE
+@item NORMAL_MODE (@var{entity})
+If this macro is defined, it is evaluated for every @var{entity} that needs
+mode switching.  It should evaluate to an integer, which is a mode that
+@var{entity} is assumed to be switched to at function entry and exit.
+
+@findex MODE_PRIORITY_TO_MODE
+@item MODE_PRIORITY_TO_MODE (@var{entity}, @var{n})
+This macro specifies the order in which modes for @var{entity} are processed.
+0 is the highest priority, @code{NUM_MODES_FOR_MODE_SWITCHING[@var{entity}] - 1} the
+lowest.  The value of the macro should be an integer designating a mode
+for @var{entity}.  For any fixed @var{entity}, @code{mode_priority_to_mode}
+(@var{entity}, @var{n}) shall be a bijection in 0 @dots{}
+@code{num_modes_for_mode_switching[@var{entity}] - 1}.
+
+@findex EMIT_MODE_SET
+@item EMIT_MODE_SET (@var{entity}, @var{mode}, @var{hard_regs_live})
+Generate one or more insns to set @var{entity} to @var{mode}.
+@var{hard_reg_live} is the set of hard registers live at the point where
+the insn(s) are to be inserted.
+@end table
+
+@node Target Attributes
+@section Defining target-specific uses of @code{__attribute__}
+@cindex target attributes
+@cindex machine attributes
+@cindex attributes, target-specific
+
+Target-specific attributes may be defined for functions, data and types.
+These are described using the following target hooks; they also need to
+be documented in @file{extend.texi}.
+
+@deftypevr {Target Hook} {const struct attribute_spec *} TARGET_ATTRIBUTE_TABLE
+If defined, this target hook points to an array of @samp{struct
+attribute_spec} (defined in @file{tree.h}) specifying the machine
+specific attributes for this target and some of the restrictions on the
+entities to which these attributes are applied and the arguments they
+take.
+@end deftypevr
+
+@deftypefn {Target Hook} int TARGET_COMP_TYPE_ATTRIBUTES (tree @var{type1}, tree @var{type2})
+If defined, this target hook is a function which returns zero if the attributes on
+@var{type1} and @var{type2} are incompatible, one if they are compatible,
+and two if they are nearly compatible (which causes a warning to be
+generated).  If this is not defined, machine-specific attributes are
+supposed always to be compatible.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SET_DEFAULT_TYPE_ATTRIBUTES (tree @var{type})
+If defined, this target hook is a function which assigns default attributes to
+newly defined @var{type}.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_MERGE_TYPE_ATTRIBUTES (tree @var{type1}, tree @var{type2})
+Define this target hook if the merging of type attributes needs special
+handling.  If defined, the result is a list of the combined
+@code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}.  It is assumed
+that @code{comptypes} has already been called and returned 1.  This
+function may call @code{merge_attributes} to handle machine-independent
+merging.
+@end deftypefn
+
+@deftypefn {Target Hook} tree TARGET_MERGE_DECL_ATTRIBUTES (tree @var{olddecl}, tree @var{newdecl})
+Define this target hook if the merging of decl attributes needs special
+handling.  If defined, the result is a list of the combined
+@code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.
+@var{newdecl} is a duplicate declaration of @var{olddecl}.  Examples of
+when this is needed are when one attribute overrides another, or when an
+attribute is nullified by a subsequent definition.  This function may
+call @code{merge_attributes} to handle machine-independent merging.
+
+@findex TARGET_DLLIMPORT_DECL_ATTRIBUTES
+If the only target-specific handling you require is @samp{dllimport} for
+Windows targets, you should define the macro
+@code{TARGET_DLLIMPORT_DECL_ATTRIBUTES}.  This links in a function
+called @code{merge_dllimport_decl_attributes} which can then be defined
+as the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}.  This is done
+in @file{i386/cygwin.h} and @file{i386/i386.c}, for example.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_INSERT_ATTRIBUTES (tree @var{node}, tree *@var{attr_ptr})
+Define this target hook if you want to be able to add attributes to a decl
+when it is being created.  This is normally useful for back ends which
+wish to implement a pragma by using the attributes which correspond to
+the pragma's effect.  The @var{node} argument is the decl which is being
+created.  The @var{attr_ptr} argument is a pointer to the attribute list
+for this decl.  The list itself should not be modified, since it may be
+shared with other decls, but attributes may be chained on the head of
+the list and @code{*@var{attr_ptr}} modified to point to the new
+attributes, or a copy of the list may be made if further changes are
+needed.
+@end deftypefn
+
+@deftypefn {Target Hook} bool TARGET_FUNCTION_ATTRIBUTE_INLINABLE_P (tree @var{fndecl})
+@cindex inlining
+This target hook returns @code{true} if it is ok to inline @var{fndecl}
+into the current function, despite its having target-specific
+attributes, @code{false} otherwise.  By default, if a function has a
+target specific attribute attached to it, it will not be inlined.
+@end deftypefn
+
+@node Misc
+@section Miscellaneous Parameters
+@cindex parameters, miscellaneous
+
+@c prevent bad page break with this line
+Here are several miscellaneous parameters.
+
+@table @code
+@item PREDICATE_CODES
+@findex PREDICATE_CODES
+Define this if you have defined special-purpose predicates in the file
+@file{@var{machine}.c}.  This macro is called within an initializer of an
+array of structures.  The first field in the structure is the name of a
+predicate and the second field is an array of rtl codes.  For each
+predicate, list all rtl codes that can be in expressions matched by the
+predicate.  The list should have a trailing comma.  Here is an example
+of two entries in the list for a typical RISC machine:
+
+@smallexample
+#define PREDICATE_CODES \
+  @{"gen_reg_rtx_operand", @{SUBREG, REG@}@},  \
+  @{"reg_or_short_cint_operand", @{SUBREG, REG, CONST_INT@}@},
+@end smallexample
+
+Defining this macro does not affect the generated code (however,
+incorrect definitions that omit an rtl code that may be matched by the
+predicate can cause the compiler to malfunction).  Instead, it allows
+the table built by @file{genrecog} to be more compact and efficient,
+thus speeding up the compiler.  The most important predicates to include
+in the list specified by this macro are those used in the most insn
+patterns.
+
+For each predicate function named in @code{PREDICATE_CODES}, a
+declaration will be generated in @file{insn-codes.h}.
+
+@item SPECIAL_MODE_PREDICATES
+@findex SPECIAL_MODE_PREDICATES
+Define this if you have special predicates that know special things
+about modes.  Genrecog will warn about certain forms of
+@code{match_operand} without a mode; if the operand predicate is
+listed in @code{SPECIAL_MODE_PREDICATES}, the warning will be
+suppressed.
+
+Here is an example from the IA-32 port (@code{ext_register_operand}
+specially checks for @code{HImode} or @code{SImode} in preparation
+for a byte extraction from @code{%ah} etc.).
+
+@smallexample
+#define SPECIAL_MODE_PREDICATES \
+  "ext_register_operand",
+@end smallexample
+
+@findex CASE_VECTOR_MODE
+@item CASE_VECTOR_MODE
+An alias for a machine mode name.  This is the machine mode that
+elements of a jump-table should have.
+
+@findex CASE_VECTOR_SHORTEN_MODE
+@item CASE_VECTOR_SHORTEN_MODE (@var{min_offset}, @var{max_offset}, @var{body})
+Optional: return the preferred mode for an @code{addr_diff_vec}
+when the minimum and maximum offset are known.  If you define this,
+it enables extra code in branch shortening to deal with @code{addr_diff_vec}.
+To make this work, you also have to define INSN_ALIGN and
+make the alignment for @code{addr_diff_vec} explicit.
+The @var{body} argument is provided so that the offset_unsigned and scale
+flags can be updated.
+
+@findex CASE_VECTOR_PC_RELATIVE
+@item CASE_VECTOR_PC_RELATIVE
+Define this macro to be a C expression to indicate when jump-tables
+should contain relative addresses.  If jump-tables never contain
+relative addresses, then you need not define this macro.
+
+@findex CASE_DROPS_THROUGH
+@item CASE_DROPS_THROUGH
+Define this if control falls through a @code{case} insn when the index
+value is out of range.  This means the specified default-label is
+actually ignored by the @code{case} insn proper.
+
+@findex CASE_VALUES_THRESHOLD
+@item CASE_VALUES_THRESHOLD
+Define this to be the smallest number of different values for which it
+is best to use a jump-table instead of a tree of conditional branches.
+The default is four for machines with a @code{casesi} instruction and
+five otherwise.  This is best for most machines.
+
+@findex WORD_REGISTER_OPERATIONS
+@item WORD_REGISTER_OPERATIONS
+Define this macro if operations between registers with integral mode
+smaller than a word are always performed on the entire register.
+Most RISC machines have this property and most CISC machines do not.
+
+@findex LOAD_EXTEND_OP
+@item LOAD_EXTEND_OP (@var{mode})
+Define this macro to be a C expression indicating when insns that read
+memory in @var{mode}, an integral mode narrower than a word, set the
+bits outside of @var{mode} to be either the sign-extension or the
+zero-extension of the data read.  Return @code{SIGN_EXTEND} for values
+of @var{mode} for which the
+insn sign-extends, @code{ZERO_EXTEND} for which it zero-extends, and
+@code{NIL} for other modes.
+
+This macro is not called with @var{mode} non-integral or with a width
+greater than or equal to @code{BITS_PER_WORD}, so you may return any
+value in this case.  Do not define this macro if it would always return
+@code{NIL}.  On machines where this macro is defined, you will normally
+define it as the constant @code{SIGN_EXTEND} or @code{ZERO_EXTEND}.
+
+@findex SHORT_IMMEDIATES_SIGN_EXTEND
+@item SHORT_IMMEDIATES_SIGN_EXTEND
+Define this macro if loading short immediate values into registers sign
+extends.
+
+@findex FIXUNS_TRUNC_LIKE_FIX_TRUNC
+@item FIXUNS_TRUNC_LIKE_FIX_TRUNC
+Define this macro if the same instructions that convert a floating
+point number to a signed fixed point number also convert validly to an
+unsigned one.
+
+@findex MOVE_MAX
+@item MOVE_MAX
+The maximum number of bytes that a single instruction can move quickly
+between memory and registers or between two memory locations.
+
+@findex MAX_MOVE_MAX
+@item MAX_MOVE_MAX
+The maximum number of bytes that a single instruction can move quickly
+between memory and registers or between two memory locations.  If this
+is undefined, the default is @code{MOVE_MAX}.  Otherwise, it is the
+constant value that is the largest value that @code{MOVE_MAX} can have
+at run-time.
+
+@findex SHIFT_COUNT_TRUNCATED
+@item SHIFT_COUNT_TRUNCATED
+A C expression that is nonzero if on this machine the number of bits
+actually used for the count of a shift operation is equal to the number
+of bits needed to represent the size of the object being shifted.  When
+this macro is nonzero, the compiler will assume that it is safe to omit
+a sign-extend, zero-extend, and certain bitwise `and' instructions that
+truncates the count of a shift operation.  On machines that have
+instructions that act on bit-fields at variable positions, which may
+include `bit test' instructions, a nonzero @code{SHIFT_COUNT_TRUNCATED}
+also enables deletion of truncations of the values that serve as
+arguments to bit-field instructions.
+
+If both types of instructions truncate the count (for shifts) and
+position (for bit-field operations), or if no variable-position bit-field
+instructions exist, you should define this macro.
+
+However, on some machines, such as the 80386 and the 680x0, truncation
+only applies to shift operations and not the (real or pretended)
+bit-field operations.  Define @code{SHIFT_COUNT_TRUNCATED} to be zero on
+such machines.  Instead, add patterns to the @file{md} file that include
+the implied truncation of the shift instructions.
+
+You need not define this macro if it would always have the value of zero.
+
+@findex TRULY_NOOP_TRUNCATION
+@item TRULY_NOOP_TRUNCATION (@var{outprec}, @var{inprec})
+A C expression which is nonzero if on this machine it is safe to
+``convert'' an integer of @var{inprec} bits to one of @var{outprec}
+bits (where @var{outprec} is smaller than @var{inprec}) by merely
+operating on it as if it had only @var{outprec} bits.
+
+On many machines, this expression can be 1.
+
+@c rearranged this, removed the phrase "it is reported that".  this was
+@c to fix an overfull hbox.  --mew 10feb93
+When @code{TRULY_NOOP_TRUNCATION} returns 1 for a pair of sizes for
+modes for which @code{MODES_TIEABLE_P} is 0, suboptimal code can result.
+If this is the case, making @code{TRULY_NOOP_TRUNCATION} return 0 in
+such cases may improve things.
+
+@findex STORE_FLAG_VALUE
+@item STORE_FLAG_VALUE
+A C expression describing the value returned by a comparison operator
+with an integral mode and stored by a store-flag instruction
+(@samp{s@var{cond}}) when the condition is true.  This description must
+apply to @emph{all} the @samp{s@var{cond}} patterns and all the
+comparison operators whose results have a @code{MODE_INT} mode.
+
+A value of 1 or @minus{}1 means that the instruction implementing the
+comparison operator returns exactly 1 or @minus{}1 when the comparison is true
+and 0 when the comparison is false.  Otherwise, the value indicates
+which bits of the result are guaranteed to be 1 when the comparison is
+true.  This value is interpreted in the mode of the comparison
+operation, which is given by the mode of the first operand in the
+@samp{s@var{cond}} pattern.  Either the low bit or the sign bit of
+@code{STORE_FLAG_VALUE} be on.  Presently, only those bits are used by
+the compiler.
+
+If @code{STORE_FLAG_VALUE} is neither 1 or @minus{}1, the compiler will
+generate code that depends only on the specified bits.  It can also
+replace comparison operators with equivalent operations if they cause
+the required bits to be set, even if the remaining bits are undefined.
+For example, on a machine whose comparison operators return an
+@code{SImode} value and where @code{STORE_FLAG_VALUE} is defined as
+@samp{0x80000000}, saying that just the sign bit is relevant, the
+expression
+
+@smallexample
+(ne:SI (and:SI @var{x} (const_int @var{power-of-2})) (const_int 0))
+@end smallexample
+
+@noindent
+can be converted to
+
+@smallexample
+(ashift:SI @var{x} (const_int @var{n}))
+@end smallexample
+
+@noindent
+where @var{n} is the appropriate shift count to move the bit being
+tested into the sign bit.
+
+There is no way to describe a machine that always sets the low-order bit
+for a true value, but does not guarantee the value of any other bits,
+but we do not know of any machine that has such an instruction.  If you
+are trying to port GCC to such a machine, include an instruction to
+perform a logical-and of the result with 1 in the pattern for the
+comparison operators and let us know at @email{gcc@@gcc.gnu.org}.
+
+Often, a machine will have multiple instructions that obtain a value
+from a comparison (or the condition codes).  Here are rules to guide the
+choice of value for @code{STORE_FLAG_VALUE}, and hence the instructions
+to be used:
+
+@itemize @bullet
+@item
+Use the shortest sequence that yields a valid definition for
+@code{STORE_FLAG_VALUE}.  It is more efficient for the compiler to
+``normalize'' the value (convert it to, e.g., 1 or 0) than for the
+comparison operators to do so because there may be opportunities to
+combine the normalization with other operations.
+
+@item
+For equal-length sequences, use a value of 1 or @minus{}1, with @minus{}1 being
+slightly preferred on machines with expensive jumps and 1 preferred on
+other machines.
+
+@item
+As a second choice, choose a value of @samp{0x80000001} if instructions
+exist that set both the sign and low-order bits but do not define the
+others.
+
+@item
+Otherwise, use a value of @samp{0x80000000}.
+@end itemize
+
+Many machines can produce both the value chosen for
+@code{STORE_FLAG_VALUE} and its negation in the same number of
+instructions.  On those machines, you should also define a pattern for
+those cases, e.g., one matching
+
+@smallexample
+(set @var{A} (neg:@var{m} (ne:@var{m} @var{B} @var{C})))
+@end smallexample
+
+Some machines can also perform @code{and} or @code{plus} operations on
+condition code values with less instructions than the corresponding
+@samp{s@var{cond}} insn followed by @code{and} or @code{plus}.  On those
+machines, define the appropriate patterns.  Use the names @code{incscc}
+and @code{decscc}, respectively, for the patterns which perform
+@code{plus} or @code{minus} operations on condition code values.  See
+@file{rs6000.md} for some examples.  The GNU Superoptizer can be used to
+find such instruction sequences on other machines.
+
+You need not define @code{STORE_FLAG_VALUE} if the machine has no store-flag
+instructions.
+
+@findex FLOAT_STORE_FLAG_VALUE
+@item FLOAT_STORE_FLAG_VALUE (@var{mode})
+A C expression that gives a nonzero @code{REAL_VALUE_TYPE} value that is
+returned when comparison operators with floating-point results are true.
+Define this macro on machine that have comparison operations that return
+floating-point values.  If there are no such operations, do not define
+this macro.
+
+@findex Pmode
+@item Pmode
+An alias for the machine mode for pointers.  On most machines, define
+this to be the integer mode corresponding to the width of a hardware
+pointer; @code{SImode} on 32-bit machine or @code{DImode} on 64-bit machines.
+On some machines you must define this to be one of the partial integer
+modes, such as @code{PSImode}.
+
+The width of @code{Pmode} must be at least as large as the value of
+@code{POINTER_SIZE}.  If it is not equal, you must define the macro
+@code{POINTERS_EXTEND_UNSIGNED} to specify how pointers are extended
+to @code{Pmode}.
+
+@findex FUNCTION_MODE
+@item FUNCTION_MODE
+An alias for the machine mode used for memory references to functions
+being called, in @code{call} RTL expressions.  On most machines this
+should be @code{QImode}.
+
+@findex INTEGRATE_THRESHOLD
+@item INTEGRATE_THRESHOLD (@var{decl})
+A C expression for the maximum number of instructions above which the
+function @var{decl} should not be inlined.  @var{decl} is a
+@code{FUNCTION_DECL} node.
+
+The default definition of this macro is 64 plus 8 times the number of
+arguments that the function accepts.  Some people think a larger
+threshold should be used on RISC machines.
+
+@findex STDC_0_IN_SYSTEM_HEADERS
+@item STDC_0_IN_SYSTEM_HEADERS
+In normal operation, the preprocessor expands @code{__STDC__} to the
+constant 1, to signify that GCC conforms to ISO Standard C@.  On some
+hosts, like Solaris, the system compiler uses a different convention,
+where @code{__STDC__} is normally 0, but is 1 if the user specifies
+strict conformance to the C Standard.
+
+Defining @code{STDC_0_IN_SYSTEM_HEADERS} makes GNU CPP follows the host
+convention when processing system header files, but when processing user
+files @code{__STDC__} will always expand to 1.
+
+@findex SCCS_DIRECTIVE
+@item SCCS_DIRECTIVE
+Define this if the preprocessor should ignore @code{#sccs} directives
+and print no error message.
+
+@findex NO_IMPLICIT_EXTERN_C
+@item NO_IMPLICIT_EXTERN_C
+Define this macro if the system header files support C++ as well as C@.
+This macro inhibits the usual method of using system header files in
+C++, which is to pretend that the file's contents are enclosed in
+@samp{extern "C" @{@dots{}@}}.
+
+@findex HANDLE_PRAGMA
+@item HANDLE_PRAGMA (@var{getc}, @var{ungetc}, @var{name})
+This macro is no longer supported.  You must use
+@code{REGISTER_TARGET_PRAGMAS} instead.
+
+@findex REGISTER_TARGET_PRAGMAS
+@findex #pragma
+@findex pragma
+@item REGISTER_TARGET_PRAGMAS (@var{pfile})
+Define this macro if you want to implement any target-specific pragmas.
+If defined, it is a C expression which makes a series of calls to
+@code{cpp_register_pragma} for each pragma, with @var{pfile} passed as
+the first argument to to these functions.  The macro may also do any
+setup required for the pragmas.
+
+The primary reason to define this macro is to provide compatibility with
+other compilers for the same target.  In general, we discourage
+definition of target-specific pragmas for GCC@.
+
+If the pragma can be implemented by attributes then you should consider
+defining the target hook @samp{TARGET_INSERT_ATTRIBUTES} as well.
+
+Preprocessor macros that appear on pragma lines are not expanded.  All
+@samp{#pragma} directives that do not match any registered pragma are
+silently ignored, unless the user specifies @option{-Wunknown-pragmas}.
+
+@deftypefun void cpp_register_pragma (cpp_reader *@var{pfile}, const char *@var{space}, const char *@var{name}, void (*@var{callback}) (cpp_reader *))
+
+Each call to @code{cpp_register_pragma} establishes one pragma.  The
+@var{callback} routine will be called when the preprocessor encounters a
+pragma of the form
+
+@smallexample
+#pragma [@var{space}] @var{name} @dots{}
+@end smallexample
+
+@var{space} is the case-sensitive namespace of the pragma, or
+@code{NULL} to put the pragma in the global namespace.  The callback
+routine receives @var{pfile} as its first argument, which can be passed
+on to cpplib's functions if necessary.  You can lex tokens after the
+@var{name} by calling @code{c_lex}.  Tokens that are not read by the
+callback will be silently ignored.  The end of the line is indicated by
+a token of type @code{CPP_EOF}.
+
+For an example use of this routine, see @file{c4x.h} and the callback
+routines defined in @file{c4x-c.c}.
+
+Note that the use of @code{c_lex} is specific to the C and C++
+compilers.  It will not work in the Java or Fortran compilers, or any
+other language compilers for that matter.  Thus if @code{c_lex} is going
+to be called from target-specific code, it must only be done so when
+building the C and C++ compilers.  This can be done by defining the
+variables @code{c_target_objs} and @code{cxx_target_objs} in the
+target entry in the @file{config.gcc} file.  These variables should name
+the target-specific, language-specific object file which contains the
+code that uses @code{c_lex}.  Note it will also be necessary to add a
+rule to the makefile fragment pointed to by @code{tmake_file} that shows
+how to build this object file.
+@end deftypefun
+
+@findex HANDLE_SYSV_PRAGMA
+@findex #pragma
+@findex pragma
+@item HANDLE_SYSV_PRAGMA
+Define this macro (to a value of 1) if you want the System V style
+pragmas @samp{#pragma pack(<n>)} and @samp{#pragma weak <name>
+[=<value>]} to be supported by gcc.
+
+The pack pragma specifies the maximum alignment (in bytes) of fields
+within a structure, in much the same way as the @samp{__aligned__} and
+@samp{__packed__} @code{__attribute__}s do.  A pack value of zero resets
+the behavior to the default.
+
+The weak pragma only works if @code{SUPPORTS_WEAK} and
+@code{ASM_WEAKEN_LABEL} are defined.  If enabled it allows the creation
+of specifically named weak labels, optionally with a value.
+
+@findex HANDLE_PRAGMA_PACK_PUSH_POP
+@findex #pragma
+@findex pragma
+@item HANDLE_PRAGMA_PACK_PUSH_POP
+Define this macro (to a value of 1) if you want to support the Win32
+style pragmas @samp{#pragma pack(push,@var{n})} and @samp{#pragma
+pack(pop)}.  The @samp{pack(push,@var{n})} pragma specifies the maximum alignment
+(in bytes) of fields within a structure, in much the same way as the
+@samp{__aligned__} and @samp{__packed__} @code{__attribute__}s do.  A
+pack value of zero resets the behavior to the default.  Successive
+invocations of this pragma cause the previous values to be stacked, so
+that invocations of @samp{#pragma pack(pop)} will return to the previous
+value.
+
+@findex DOLLARS_IN_IDENTIFIERS
+@item DOLLARS_IN_IDENTIFIERS
+Define this macro to control use of the character @samp{$} in identifier
+names.  0 means @samp{$} is not allowed by default; 1 means it is allowed.
+1 is the default; there is no need to define this macro in that case.
+This macro controls the compiler proper; it does not affect the preprocessor.
+
+@findex NO_DOLLAR_IN_LABEL
+@item NO_DOLLAR_IN_LABEL
+Define this macro if the assembler does not accept the character
+@samp{$} in label names.  By default constructors and destructors in
+G++ have @samp{$} in the identifiers.  If this macro is defined,
+@samp{.} is used instead.
+
+@findex NO_DOT_IN_LABEL
+@item NO_DOT_IN_LABEL
+Define this macro if the assembler does not accept the character
+@samp{.} in label names.  By default constructors and destructors in G++
+have names that use @samp{.}.  If this macro is defined, these names
+are rewritten to avoid @samp{.}.
+
+@findex DEFAULT_MAIN_RETURN
+@item DEFAULT_MAIN_RETURN
+Define this macro if the target system expects every program's @code{main}
+function to return a standard ``success'' value by default (if no other
+value is explicitly returned).
+
+The definition should be a C statement (sans semicolon) to generate the
+appropriate rtl instructions.  It is used only when compiling the end of
+@code{main}.
+
+@item NEED_ATEXIT
+@findex NEED_ATEXIT
+Define this if the target system lacks the function @code{atexit}
+from the ISO C standard.  If this macro is defined, a default definition
+will be provided to support C++.  If @code{ON_EXIT} is not defined,
+a default @code{exit} function will also be provided.
+
+@item ON_EXIT
+@findex ON_EXIT
+Define this macro if the target has another way to implement atexit
+functionality without replacing @code{exit}.  For instance, SunOS 4 has
+a similar @code{on_exit} library function.
+
+The definition should be a functional macro which can be used just like
+the @code{atexit} function.
+
+@item EXIT_BODY
+@findex EXIT_BODY
+Define this if your @code{exit} function needs to do something
+besides calling an external function @code{_cleanup} before
+terminating with @code{_exit}.  The @code{EXIT_BODY} macro is
+only needed if @code{NEED_ATEXIT} is defined and @code{ON_EXIT} is not
+defined.
+
+@findex INSN_SETS_ARE_DELAYED
+@item INSN_SETS_ARE_DELAYED (@var{insn})
+Define this macro as a C expression that is nonzero if it is safe for the
+delay slot scheduler to place instructions in the delay slot of @var{insn},
+even if they appear to use a resource set or clobbered in @var{insn}.
+@var{insn} is always a @code{jump_insn} or an @code{insn}; GCC knows that
+every @code{call_insn} has this behavior.  On machines where some @code{insn}
+or @code{jump_insn} is really a function call and hence has this behavior,
+you should define this macro.
+
+You need not define this macro if it would always return zero.
+
+@findex INSN_REFERENCES_ARE_DELAYED
+@item INSN_REFERENCES_ARE_DELAYED (@var{insn})
+Define this macro as a C expression that is nonzero if it is safe for the
+delay slot scheduler to place instructions in the delay slot of @var{insn},
+even if they appear to set or clobber a resource referenced in @var{insn}.
+@var{insn} is always a @code{jump_insn} or an @code{insn}.  On machines where
+some @code{insn} or @code{jump_insn} is really a function call and its operands
+are registers whose use is actually in the subroutine it calls, you should
+define this macro.  Doing so allows the delay slot scheduler to move
+instructions which copy arguments into the argument registers into the delay
+slot of @var{insn}.
+
+You need not define this macro if it would always return zero.
+
+@findex MACHINE_DEPENDENT_REORG
+@item MACHINE_DEPENDENT_REORG (@var{insn})
+In rare cases, correct code generation requires extra machine
+dependent processing between the second jump optimization pass and
+delayed branch scheduling.  On those machines, define this macro as a C
+statement to act on the code starting at @var{insn}.
+
+@findex MULTIPLE_SYMBOL_SPACES
+@item MULTIPLE_SYMBOL_SPACES
+Define this macro if in some cases global symbols from one translation
+unit may not be bound to undefined symbols in another translation unit
+without user intervention.  For instance, under Microsoft Windows
+symbols must be explicitly imported from shared libraries (DLLs).
+
+@findex MD_ASM_CLOBBERS
+@item MD_ASM_CLOBBERS (@var{clobbers})
+A C statement that adds to @var{clobbers} @code{STRING_CST} trees for
+any hard regs the port wishes to automatically clobber for all asms.
+
+@findex MAX_INTEGER_COMPUTATION_MODE
+@item MAX_INTEGER_COMPUTATION_MODE
+Define this to the largest integer machine mode which can be used for
+operations other than load, store and copy operations.
+
+You need only define this macro if the target holds values larger than
+@code{word_mode} in general purpose registers.  Most targets should not define
+this macro.
+
+@findex MATH_LIBRARY
+@item MATH_LIBRARY
+Define this macro as a C string constant for the linker argument to link
+in the system math library, or @samp{""} if the target does not have a
+separate math library.
+
+You need only define this macro if the default of @samp{"-lm"} is wrong.
+
+@findex LIBRARY_PATH_ENV
+@item LIBRARY_PATH_ENV
+Define this macro as a C string constant for the environment variable that
+specifies where the linker should look for libraries.
+
+You need only define this macro if the default of @samp{"LIBRARY_PATH"}
+is wrong.
+
+@findex TARGET_HAS_F_SETLKW
+@item TARGET_HAS_F_SETLKW
+Define this macro if the target supports file locking with fcntl / F_SETLKW@.
+Note that this functionality is part of POSIX@.
+Defining @code{TARGET_HAS_F_SETLKW} will enable the test coverage code
+to use file locking when exiting a program, which avoids race conditions
+if the program has forked.
+
+@findex MAX_CONDITIONAL_EXECUTE
+@item MAX_CONDITIONAL_EXECUTE
+
+A C expression for the maximum number of instructions to execute via
+conditional execution instructions instead of a branch.  A value of
+@code{BRANCH_COST}+1 is the default if the machine does not use cc0, and
+1 if it does use cc0.
+
+@findex IFCVT_MODIFY_TESTS
+@item IFCVT_MODIFY_TESTS
+A C expression to modify the tests in @code{TRUE_EXPR}, and
+@code{FALSE_EXPR} for use in converting insns in @code{TEST_BB},
+@code{THEN_BB}, @code{ELSE_BB}, and @code{JOIN_BB} basic blocks to
+conditional execution.  Set either @code{TRUE_EXPR} or @code{FALSE_EXPR}
+to a null pointer if the tests cannot be converted.
+
+@findex IFCVT_MODIFY_INSN
+@item IFCVT_MODIFY_INSN
+A C expression to modify the @code{PATTERN} of an @code{INSN} that is to
+be converted to conditional execution format.
+
+@findex IFCVT_MODIFY_FINAL
+@item IFCVT_MODIFY_FINAL
+A C expression to perform any final machine dependent modifications in
+converting code to conditional execution in the basic blocks
+@code{TEST_BB}, @code{THEN_BB}, @code{ELSE_BB}, and @code{JOIN_BB}.
+
+@findex IFCVT_MODIFY_CANCEL
+@item IFCVT_MODIFY_CANCEL
+A C expression to cancel any machine dependent modifications in
+converting code to conditional execution in the basic blocks
+@code{TEST_BB}, @code{THEN_BB}, @code{ELSE_BB}, and @code{JOIN_BB}.
+@end table
+
+@deftypefn {Target Hook} void TARGET_INIT_BUILTINS ()
+Define this hook if you have any machine-specific built-in functions
+that need to be defined.  It should be a function that performs the
+necessary setup.
+
+Machine specific built-in functions can be useful to expand special machine
+instructions that would otherwise not normally be generated because
+they have no equivalent in the source language (for example, SIMD vector
+instructions or prefetch instructions).
+
+To create a built-in function, call the function @code{builtin_function}
+which is defined by the language front end.  You can use any type nodes set
+up by @code{build_common_tree_nodes} and @code{build_common_tree_nodes_2};
+only language front ends that use those two functions will call
+@samp{TARGET_INIT_BUILTINS}.
+@end deftypefn
+
+@deftypefn {Target Hook} rtx TARGET_EXPAND_BUILTIN (tree @var{exp}, rtx @var{target}, rtx @var{subtarget}, enum machine_mode @var{mode}, int @var{ignore})
+
+Expand a call to a machine specific built-in function that was set up by
+@samp{TARGET_INIT_BUILTINS}.  @var{exp} is the expression for the
+function call; the result should go to @var{target} if that is
+convenient, and have mode @var{mode} if that is convenient.
+@var{subtarget} may be used as the target for computing one of
+@var{exp}'s operands.  @var{ignore} is nonzero if the value is to be
+ignored.  This function should return the result of the call to the
+built-in function.
+@end deftypefn
+
+@table @code
+@findex MD_CAN_REDIRECT_BRANCH
+@item MD_CAN_REDIRECT_BRANCH(@var{branch1}, @var{branch2})
+
+Take a branch insn in @var{branch1} and another in @var{branch2}.
+Return true if redirecting @var{branch1} to the destination of
+@var{branch2} is possible.
+
+On some targets, branches may have a limited range.  Optimizing the
+filling of delay slots can result in branches being redirected, and this
+may in turn cause a branch offset to overflow.
+
+@findex ALLOCATE_INITIAL_VALUE
+@item ALLOCATE_INITIAL_VALUE(@var{hard_reg})
+
+When the initial value of a hard register has been copied in a pseudo
+register, it is often not necessary to actually allocate another register
+to this pseudo register, because the original hard register or a stack slot
+it has been saved into can be used.  @code{ALLOCATE_INITIAL_VALUE}, if
+defined, is called at the start of register allocation once for each
+hard register that had its initial value copied by using
+@code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.
+Possible values are @code{NULL_RTX}, if you don't want
+to do any special allocation, a @code{REG} rtx---that would typically be
+the hard register itself, if it is known not to be clobbered---or a
+@code{MEM}.
+If you are returning a @code{MEM}, this is only a hint for the allocator;
+it might decide to use another register anyways.
+You may use @code{current_function_leaf_function} in the definition of the
+macro, functions that use @code{REG_N_SETS}, to determine if the hard
+register in question will not be clobbered.
+
+@findex TARGET_OBJECT_SUFFIX
+@item TARGET_OBJECT_SUFFIX
+Define this macro to be a C string representing the suffix for object
+files on your target machine.  If you do not define this macro, GCC will
+use @samp{.o} as the suffix for object files.
+
+@findex TARGET_EXECUTABLE_SUFFIX
+@item TARGET_EXECUTABLE_SUFFIX
+Define this macro to be a C string representing the suffix to be
+automatically added to executable files on your target machine.  If you
+do not define this macro, GCC will use the null string as the suffix for
+executable files.
+
+@findex COLLECT_EXPORT_LIST
+@item COLLECT_EXPORT_LIST
+If defined, @code{collect2} will scan the individual object files
+specified on its command line and create an export list for the linker.
+Define this macro for systems like AIX, where the linker discards
+object files that are not referenced from @code{main} and uses export
+lists.
+
+@end table
diff --git a/contrib/gcc/doc/trouble.texi b/contrib/gcc/doc/trouble.texi
new file mode 100644
index 0000000..09026fe
--- /dev/null
+++ b/contrib/gcc/doc/trouble.texi
@@ -0,0 +1,1462 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+@c 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Trouble
+@chapter Known Causes of Trouble with GCC
+@cindex bugs, known
+@cindex installation trouble
+@cindex known causes of trouble
+
+This section describes known problems that affect users of GCC@.  Most
+of these are not GCC bugs per se---if they were, we would fix them.
+But the result for a user may be like the result of a bug.
+
+Some of these problems are due to bugs in other software, some are
+missing features that are too much work to add, and some are places
+where people's opinions differ as to what is best.
+
+@menu
+* Actual Bugs::		      Bugs we will fix later.
+* Cross-Compiler Problems::   Common problems of cross compiling with GCC.
+* Interoperation::      Problems using GCC with other compilers,
+			   and with certain linkers, assemblers and debuggers.
+* External Bugs::	Problems compiling certain programs.
+* Incompatibilities::   GCC is incompatible with traditional C.
+* Fixed Headers::       GCC uses corrected versions of system header files.
+                           This is necessary, but doesn't always work smoothly.
+* Standard Libraries::  GCC uses the system C library, which might not be
+                           compliant with the ISO C standard.
+* Disappointments::     Regrettable things we can't change, but not quite bugs.
+* C++ Misunderstandings::     Common misunderstandings with GNU C++.
+* Protoize Caveats::    Things to watch out for when using @code{protoize}.
+* Non-bugs::		Things we think are right, but some others disagree.
+* Warnings and Errors:: Which problems in your code get warnings,
+                         and which get errors.
+@end menu
+
+@node Actual Bugs
+@section Actual Bugs We Haven't Fixed Yet
+
+@itemize @bullet
+@item
+The @code{fixincludes} script interacts badly with automounters; if the
+directory of system header files is automounted, it tends to be
+unmounted while @code{fixincludes} is running.  This would seem to be a
+bug in the automounter.  We don't know any good way to work around it.
+
+@item
+The @code{fixproto} script will sometimes add prototypes for the
+@code{sigsetjmp} and @code{siglongjmp} functions that reference the
+@code{jmp_buf} type before that type is defined.  To work around this,
+edit the offending file and place the typedef in front of the
+prototypes.
+
+@item
+@opindex pedantic-errors
+When @option{-pedantic-errors} is specified, GCC will incorrectly give
+an error message when a function name is specified in an expression
+involving the comma operator.
+@end itemize
+
+@node Cross-Compiler Problems
+@section Cross-Compiler Problems
+
+You may run into problems with cross compilation on certain machines,
+for several reasons.
+
+@itemize @bullet
+@item
+Cross compilation can run into trouble for certain machines because
+some target machines' assemblers require floating point numbers to be
+written as @emph{integer} constants in certain contexts.
+
+The compiler writes these integer constants by examining the floating
+point value as an integer and printing that integer, because this is
+simple to write and independent of the details of the floating point
+representation.  But this does not work if the compiler is running on
+a different machine with an incompatible floating point format, or
+even a different byte-ordering.
+
+In addition, correct constant folding of floating point values
+requires representing them in the target machine's format.
+(The C standard does not quite require this, but in practice
+it is the only way to win.)
+
+It is now possible to overcome these problems by defining macros such
+as @code{REAL_VALUE_TYPE}.  But doing so is a substantial amount of
+work for each target machine.
+@xref{Cross-compilation,,Cross Compilation and Floating Point,
+gccint, GNU Compiler Collection (GCC) Internals}.
+
+@item
+At present, the program @file{mips-tfile} which adds debug
+support to object files on MIPS systems does not work in a cross
+compile environment.
+@end itemize
+
+@node Interoperation
+@section Interoperation
+
+This section lists various difficulties encountered in using GCC
+together with other compilers or with the assemblers, linkers,
+libraries and debuggers on certain systems.
+
+@itemize @bullet
+@item
+G++ does not do name mangling in the same way as other C++
+compilers.  This means that object files compiled with one compiler
+cannot be used with another.
+
+This effect is intentional, to protect you from more subtle problems.
+Compilers differ as to many internal details of C++ implementation,
+including: how class instances are laid out, how multiple inheritance is
+implemented, and how virtual function calls are handled.  If the name
+encoding were made the same, your programs would link against libraries
+provided from other compilers---but the programs would then crash when
+run.  Incompatible libraries are then detected at link time, rather than
+at run time.
+
+@item
+Older GDB versions sometimes fail to read the output of GCC version
+2.  If you have trouble, get GDB version 4.4 or later.
+
+@item
+@cindex DBX
+DBX rejects some files produced by GCC, though it accepts similar
+constructs in output from PCC@.  Until someone can supply a coherent
+description of what is valid DBX input and what is not, there is
+nothing I can do about these problems.  You are on your own.
+
+@item
+The GNU assembler (GAS) does not support PIC@.  To generate PIC code, you
+must use some other assembler, such as @file{/bin/as}.
+
+@item
+On some BSD systems, including some versions of Ultrix, use of profiling
+causes static variable destructors (currently used only in C++) not to
+be run.
+
+@ignore
+@cindex @code{vfork}, for the Sun-4
+@item
+There is a bug in @code{vfork} on the Sun-4 which causes the registers
+of the child process to clobber those of the parent.  Because of this,
+programs that call @code{vfork} are likely to lose when compiled
+optimized with GCC when the child code alters registers which contain
+C variables in the parent.  This affects variables which are live in the
+parent across the call to @code{vfork}.
+
+If you encounter this, you can work around the problem by declaring
+variables @code{volatile} in the function that calls @code{vfork}, until
+the problem goes away, or by not declaring them @code{register} and not
+using @option{-O} for those source files.
+@end ignore
+
+@item
+On some SGI systems, when you use @option{-lgl_s} as an option,
+it gets translated magically to @samp{-lgl_s -lX11_s -lc_s}.
+Naturally, this does not happen when you use GCC@.
+You must specify all three options explicitly.
+
+@item
+On a Sparc, GCC aligns all values of type @code{double} on an 8-byte
+boundary, and it expects every @code{double} to be so aligned.  The Sun
+compiler usually gives @code{double} values 8-byte alignment, with one
+exception: function arguments of type @code{double} may not be aligned.
+
+As a result, if a function compiled with Sun CC takes the address of an
+argument of type @code{double} and passes this pointer of type
+@code{double *} to a function compiled with GCC, dereferencing the
+pointer may cause a fatal signal.
+
+One way to solve this problem is to compile your entire program with GCC@.
+Another solution is to modify the function that is compiled with
+Sun CC to copy the argument into a local variable; local variables
+are always properly aligned.  A third solution is to modify the function
+that uses the pointer to dereference it via the following function
+@code{access_double} instead of directly with @samp{*}:
+
+@smallexample
+inline double
+access_double (double *unaligned_ptr)
+@{
+  union d2i @{ double d; int i[2]; @};
+
+  union d2i *p = (union d2i *) unaligned_ptr;
+  union d2i u;
+
+  u.i[0] = p->i[0];
+  u.i[1] = p->i[1];
+
+  return u.d;
+@}
+@end smallexample
+
+@noindent
+Storing into the pointer can be done likewise with the same union.
+
+@item
+On Solaris, the @code{malloc} function in the @file{libmalloc.a} library
+may allocate memory that is only 4 byte aligned.  Since GCC on the
+Sparc assumes that doubles are 8 byte aligned, this may result in a
+fatal signal if doubles are stored in memory allocated by the
+@file{libmalloc.a} library.
+
+The solution is to not use the @file{libmalloc.a} library.  Use instead
+@code{malloc} and related functions from @file{libc.a}; they do not have
+this problem.
+
+@item
+Sun forgot to include a static version of @file{libdl.a} with some
+versions of SunOS (mainly 4.1).  This results in undefined symbols when
+linking static binaries (that is, if you use @option{-static}).  If you
+see undefined symbols @code{_dlclose}, @code{_dlsym} or @code{_dlopen}
+when linking, compile and link against the file
+@file{mit/util/misc/dlsym.c} from the MIT version of X windows.
+
+@item
+The 128-bit long double format that the Sparc port supports currently
+works by using the architecturally defined quad-word floating point
+instructions.  Since there is no hardware that supports these
+instructions they must be emulated by the operating system.  Long
+doubles do not work in Sun OS versions 4.0.3 and earlier, because the
+kernel emulator uses an obsolete and incompatible format.  Long doubles
+do not work in Sun OS version 4.1.1 due to a problem in a Sun library.
+Long doubles do work on Sun OS versions 4.1.2 and higher, but GCC
+does not enable them by default.  Long doubles appear to work in Sun OS
+5.x (Solaris 2.x).
+
+@item
+On HP-UX version 9.01 on the HP PA, the HP compiler @code{cc} does not
+compile GCC correctly.  We do not yet know why.  However, GCC
+compiled on earlier HP-UX versions works properly on HP-UX 9.01 and can
+compile itself properly on 9.01.
+
+@item
+On the HP PA machine, ADB sometimes fails to work on functions compiled
+with GCC@.  Specifically, it fails to work on functions that use
+@code{alloca} or variable-size arrays.  This is because GCC doesn't
+generate HP-UX unwind descriptors for such functions.  It may even be
+impossible to generate them.
+
+@item
+Debugging (@option{-g}) is not supported on the HP PA machine, unless you use
+the preliminary GNU tools.
+
+@item
+Taking the address of a label may generate errors from the HP-UX
+PA assembler.  GAS for the PA does not have this problem.
+
+@item
+Using floating point parameters for indirect calls to static functions
+will not work when using the HP assembler.  There simply is no way for GCC
+to specify what registers hold arguments for static functions when using
+the HP assembler.  GAS for the PA does not have this problem.
+
+@item
+In extremely rare cases involving some very large functions you may
+receive errors from the HP linker complaining about an out of bounds
+unconditional branch offset.  This used to occur more often in previous
+versions of GCC, but is now exceptionally rare.  If you should run
+into it, you can work around by making your function smaller.
+
+@item
+GCC compiled code sometimes emits warnings from the HP-UX assembler of
+the form:
+
+@smallexample
+(warning) Use of GR3 when
+  frame >= 8192 may cause conflict.
+@end smallexample
+
+These warnings are harmless and can be safely ignored.
+
+@item
+On the IBM RS/6000, compiling code of the form
+
+@smallexample
+extern int foo;
+
+@dots{} foo @dots{}
+
+static int foo;
+@end smallexample
+
+@noindent
+will cause the linker to report an undefined symbol @code{foo}.
+Although this behavior differs from most other systems, it is not a
+bug because redefining an @code{extern} variable as @code{static}
+is undefined in ISO C@.
+
+@item
+In extremely rare cases involving some very large functions you may
+receive errors from the AIX Assembler complaining about a displacement
+that is too large.  If you should run into it, you can work around by
+making your function smaller.
+
+@item
+The @file{libstdc++.a} library in GCC relies on the SVR4 dynamic
+linker semantics which merges global symbols between libraries and
+applications, especially necessary for C++ streams functionality.
+This is not the default behavior of AIX shared libraries and dynamic
+linking.  @file{libstdc++.a} is built on AIX with ``runtime-linking''
+enabled so that symbol merging can occur.  To utilize this feature,
+the application linked with @file{libstdc++.a} must include the
+@option{-Wl,-brtl} flag on the link line.  G++ cannot impose this
+because this option may interfere with the semantics of the user
+program and users may not always use @samp{g++} to link his or her
+application. Applications are not required to use the
+@option{-Wl,-brtl} flag on the link line---the rest of the
+@file{libstdc++.a} library which is not dependent on the symbol
+merging semantics will continue to function correctly.
+
+@item
+An application can interpose its own definition of functions for
+functions invoked by @file{libstdc++.a} with ``runtime-linking''
+enabled on AIX.  To accomplish this the application must be linked
+with ``runtime-linking'' option and the functions explicitly must be
+exported by the application (@option{-Wl,-brtl,-bE:exportfile}).
+
+@item
+AIX on the RS/6000 provides support (NLS) for environments outside of
+the United States.  Compilers and assemblers use NLS to support
+locale-specific representations of various objects including
+floating-point numbers (@samp{.} vs @samp{,} for separating decimal
+fractions). There have been problems reported where the library linked
+with GCC does not produce the same floating-point formats that the
+assembler accepts. If you have this problem, set the @env{LANG}
+environment variable to @samp{C} or @samp{En_US}.
+
+@item
+@opindex fdollars-in-identifiers
+Even if you specify @option{-fdollars-in-identifiers},
+you cannot successfully use @samp{$} in identifiers on the RS/6000 due
+to a restriction in the IBM assembler.  GAS supports these
+identifiers.
+
+@item
+@opindex mno-serialize-volatile
+There is an assembler bug in versions of DG/UX prior to 5.4.2.01 that
+occurs when the @samp{fldcr} instruction is used.  GCC uses
+@samp{fldcr} on the 88100 to serialize volatile memory references.  Use
+the option @option{-mno-serialize-volatile} if your version of the
+assembler has this bug.
+
+@item
+On VMS, GAS versions 1.38.1 and earlier may cause spurious warning
+messages from the linker.  These warning messages complain of mismatched
+psect attributes.  You can ignore them.
+
+@item
+On NewsOS version 3, if you include both of the files @file{stddef.h}
+and @file{sys/types.h}, you get an error because there are two typedefs
+of @code{size_t}.  You should change @file{sys/types.h} by adding these
+lines around the definition of @code{size_t}:
+
+@smallexample
+#ifndef _SIZE_T
+#define _SIZE_T
+@var{actual-typedef-here}
+#endif
+@end smallexample
+
+@cindex Alliant
+@item
+On the Alliant, the system's own convention for returning structures
+and unions is unusual, and is not compatible with GCC no matter
+what options are used.
+
+@cindex RT PC
+@cindex IBM RT PC
+@item
+@opindex mhc-struct-return
+On the IBM RT PC, the MetaWare HighC compiler (hc) uses a different
+convention for structure and union returning.  Use the option
+@option{-mhc-struct-return} to tell GCC to use a convention compatible
+with it.
+
+@cindex VAX calling convention
+@cindex Ultrix calling convention
+@item
+@opindex fcall-saved
+On Ultrix, the Fortran compiler expects registers 2 through 5 to be saved
+by function calls.  However, the C compiler uses conventions compatible
+with BSD Unix: registers 2 through 5 may be clobbered by function calls.
+
+GCC uses the same convention as the Ultrix C compiler.  You can use
+these options to produce code compatible with the Fortran compiler:
+
+@smallexample
+-fcall-saved-r2 -fcall-saved-r3 -fcall-saved-r4 -fcall-saved-r5
+@end smallexample
+
+@item
+On the WE32k, you may find that programs compiled with GCC do not
+work with the standard shared C library.  You may need to link with
+the ordinary C compiler.  If you do so, you must specify the following
+options:
+
+@smallexample
+-L/usr/local/lib/gcc-lib/we32k-att-sysv/2.8.1 -lgcc -lc_s
+@end smallexample
+
+The first specifies where to find the library @file{libgcc.a}
+specified with the @option{-lgcc} option.
+
+GCC does linking by invoking @command{ld}, just as @command{cc} does, and
+there is no reason why it @emph{should} matter which compilation program
+you use to invoke @command{ld}.  If someone tracks this problem down,
+it can probably be fixed easily.
+
+@item
+On the Alpha, you may get assembler errors about invalid syntax as a
+result of floating point constants.  This is due to a bug in the C
+library functions @code{ecvt}, @code{fcvt} and @code{gcvt}.  Given valid
+floating point numbers, they sometimes print @samp{NaN}.
+
+@item
+On Irix 4.0.5F (and perhaps in some other versions), an assembler bug
+sometimes reorders instructions incorrectly when optimization is turned
+on.  If you think this may be happening to you, try using the GNU
+assembler; GAS version 2.1 supports ECOFF on Irix.
+
+@opindex noasmopt
+Or use the @option{-noasmopt} option when you compile GCC with itself,
+and then again when you compile your program.  (This is a temporary
+kludge to turn off assembler optimization on Irix.)  If this proves to
+be what you need, edit the assembler spec in the file @file{specs} so
+that it unconditionally passes @option{-O0} to the assembler, and never
+passes @option{-O2} or @option{-O3}.
+@end itemize
+
+@node External Bugs
+@section Problems Compiling Certain Programs
+
+@c prevent bad page break with this line
+Certain programs have problems compiling.
+
+@itemize @bullet
+@item
+Parse errors may occur compiling X11 on a Decstation running Ultrix 4.2
+because of problems in DEC's versions of the X11 header files
+@file{X11/Xlib.h} and @file{X11/Xutil.h}.  People recommend adding
+@option{-I/usr/include/mit} to use the MIT versions of the header files,
+using the @option{-traditional} switch to turn off ISO C, or fixing the
+header files by adding this:
+
+@example
+#ifdef __STDC__
+#define NeedFunctionPrototypes 0
+#endif
+@end example
+
+@item
+On various 386 Unix systems derived from System V, including SCO, ISC,
+and ESIX, you may get error messages about running out of virtual memory
+while compiling certain programs.
+
+You can prevent this problem by linking GCC with the GNU malloc
+(which thus replaces the malloc that comes with the system).  GNU malloc
+is available as a separate package, and also in the file
+@file{src/gmalloc.c} in the GNU Emacs 19 distribution.
+
+If you have installed GNU malloc as a separate library package, use this
+option when you relink GCC:
+
+@example
+MALLOC=/usr/local/lib/libgmalloc.a
+@end example
+
+Alternatively, if you have compiled @file{gmalloc.c} from Emacs 19, copy
+the object file to @file{gmalloc.o} and use this option when you relink
+GCC:
+
+@example
+MALLOC=gmalloc.o
+@end example
+@end itemize
+
+@node Incompatibilities
+@section Incompatibilities of GCC
+@cindex incompatibilities of GCC
+@opindex traditional
+
+There are several noteworthy incompatibilities between GNU C and K&R
+(non-ISO) versions of C@.  The @option{-traditional} option
+eliminates many of these incompatibilities, @emph{but not all}, by
+telling GCC to behave like a K&R C compiler.
+
+@itemize @bullet
+@cindex string constants
+@cindex read-only strings
+@cindex shared strings
+@item
+GCC normally makes string constants read-only.  If several
+identical-looking string constants are used, GCC stores only one
+copy of the string.
+
+@cindex @code{mktemp}, and constant strings
+One consequence is that you cannot call @code{mktemp} with a string
+constant argument.  The function @code{mktemp} always alters the
+string its argument points to.
+
+@cindex @code{sscanf}, and constant strings
+@cindex @code{fscanf}, and constant strings
+@cindex @code{scanf}, and constant strings
+Another consequence is that @code{sscanf} does not work on some systems
+when passed a string constant as its format control string or input.
+This is because @code{sscanf} incorrectly tries to write into the string
+constant.  Likewise @code{fscanf} and @code{scanf}.
+
+@opindex fwritable-strings
+The best solution to these problems is to change the program to use
+@code{char}-array variables with initialization strings for these
+purposes instead of string constants.  But if this is not possible,
+you can use the @option{-fwritable-strings} flag, which directs GCC
+to handle string constants the same way most C compilers do.
+@option{-traditional} also has this effect, among others.
+
+@item
+@code{-2147483648} is positive.
+
+This is because 2147483648 cannot fit in the type @code{int}, so
+(following the ISO C rules) its data type is @code{unsigned long int}.
+Negating this value yields 2147483648 again.
+
+@item
+GCC does not substitute macro arguments when they appear inside of
+string constants.  For example, the following macro in GCC
+
+@example
+#define foo(a) "a"
+@end example
+
+@noindent
+will produce output @code{"a"} regardless of what the argument @var{a} is.
+
+The @option{-traditional} option directs GCC to handle such cases
+(among others) in the old-fashioned (non-ISO) fashion.
+
+@cindex @code{setjmp} incompatibilities
+@cindex @code{longjmp} incompatibilities
+@item
+When you use @code{setjmp} and @code{longjmp}, the only automatic
+variables guaranteed to remain valid are those declared
+@code{volatile}.  This is a consequence of automatic register
+allocation.  Consider this function:
+
+@example
+jmp_buf j;
+
+foo ()
+@{
+  int a, b;
+
+  a = fun1 ();
+  if (setjmp (j))
+    return a;
+
+  a = fun2 ();
+  /* @r{@code{longjmp (j)} may occur in @code{fun3}.} */
+  return a + fun3 ();
+@}
+@end example
+
+Here @code{a} may or may not be restored to its first value when the
+@code{longjmp} occurs.  If @code{a} is allocated in a register, then
+its first value is restored; otherwise, it keeps the last value stored
+in it.
+
+@opindex W
+If you use the @option{-W} option with the @option{-O} option, you will
+get a warning when GCC thinks such a problem might be possible.
+
+The @option{-traditional} option directs GCC to put variables in
+the stack by default, rather than in registers, in functions that
+call @code{setjmp}.  This results in the behavior found in
+traditional C compilers.
+
+@item
+Programs that use preprocessing directives in the middle of macro
+arguments do not work with GCC@.  For example, a program like this
+will not work:
+
+@example
+@group
+foobar (
+#define luser
+        hack)
+@end group
+@end example
+
+ISO C does not permit such a construct.  It would make sense to support
+it when @option{-traditional} is used, but it is too much work to
+implement.
+
+@item
+K&R compilers allow comments to cross over an inclusion boundary
+(i.e.@: started in an include file and ended in the including file).  I think
+this would be quite ugly and can't imagine it could be needed.
+
+@cindex external declaration scope
+@cindex scope of external declarations
+@cindex declaration scope
+@item
+Declarations of external variables and functions within a block apply
+only to the block containing the declaration.  In other words, they
+have the same scope as any other declaration in the same place.
+
+In some other C compilers, a @code{extern} declaration affects all the
+rest of the file even if it happens within a block.
+
+The @option{-traditional} option directs GCC to treat all @code{extern}
+declarations as global, like traditional compilers.
+
+@item
+In traditional C, you can combine @code{long}, etc., with a typedef name,
+as shown here:
+
+@example
+typedef int foo;
+typedef long foo bar;
+@end example
+
+In ISO C, this is not allowed: @code{long} and other type modifiers
+require an explicit @code{int}.  Because this criterion is expressed
+by Bison grammar rules rather than C code, the @option{-traditional}
+flag cannot alter it.
+
+@cindex typedef names as function parameters
+@item
+PCC allows typedef names to be used as function parameters.  The
+difficulty described immediately above applies here too.
+
+@item
+When in @option{-traditional} mode, GCC allows the following erroneous
+pair of declarations to appear together in a given scope:
+
+@example
+typedef int foo;
+typedef foo foo;
+@end example
+
+@item
+GCC treats all characters of identifiers as significant, even when in
+@option{-traditional} mode.  According to K&R-1 (2.2), ``No more than the
+first eight characters are significant, although more may be used.''.
+Also according to K&R-1 (2.2), ``An identifier is a sequence of letters
+and digits; the first character must be a letter.  The underscore _
+counts as a letter.'', but GCC also allows dollar signs in identifiers.
+
+@cindex whitespace
+@item
+PCC allows whitespace in the middle of compound assignment operators
+such as @samp{+=}.  GCC, following the ISO standard, does not
+allow this.  The difficulty described immediately above applies here
+too.
+
+@cindex apostrophes
+@cindex '
+@item
+GCC complains about unterminated character constants inside of
+preprocessing conditionals that fail.  Some programs have English
+comments enclosed in conditionals that are guaranteed to fail; if these
+comments contain apostrophes, GCC will probably report an error.  For
+example, this code would produce an error:
+
+@example
+#if 0
+You can't expect this to work.
+#endif
+@end example
+
+The best solution to such a problem is to put the text into an actual
+C comment delimited by @samp{/*@dots{}*/}.  However,
+@option{-traditional} suppresses these error messages.
+
+@item
+Many user programs contain the declaration @samp{long time ();}.  In the
+past, the system header files on many systems did not actually declare
+@code{time}, so it did not matter what type your program declared it to
+return.  But in systems with ISO C headers, @code{time} is declared to
+return @code{time_t}, and if that is not the same as @code{long}, then
+@samp{long time ();} is erroneous.
+
+The solution is to change your program to use appropriate system headers
+(@code{<time.h>} on systems with ISO C headers) and not to declare
+@code{time} if the system header files declare it, or failing that to
+use @code{time_t} as the return type of @code{time}.
+
+@cindex @code{float} as function value type
+@item
+When compiling functions that return @code{float}, PCC converts it to
+a double.  GCC actually returns a @code{float}.  If you are concerned
+with PCC compatibility, you should declare your functions to return
+@code{double}; you might as well say what you mean.
+
+@cindex structures
+@cindex unions
+@item
+When compiling functions that return structures or unions, GCC
+output code normally uses a method different from that used on most
+versions of Unix.  As a result, code compiled with GCC cannot call
+a structure-returning function compiled with PCC, and vice versa.
+
+The method used by GCC is as follows: a structure or union which is
+1, 2, 4 or 8 bytes long is returned like a scalar.  A structure or union
+with any other size is stored into an address supplied by the caller
+(usually in a special, fixed register, but on some machines it is passed
+on the stack).  The machine-description macros @code{STRUCT_VALUE} and
+@code{STRUCT_INCOMING_VALUE} tell GCC where to pass this address.
+
+By contrast, PCC on most target machines returns structures and unions
+of any size by copying the data into an area of static storage, and then
+returning the address of that storage as if it were a pointer value.
+The caller must copy the data from that memory area to the place where
+the value is wanted.  GCC does not use this method because it is
+slower and nonreentrant.
+
+On some newer machines, PCC uses a reentrant convention for all
+structure and union returning.  GCC on most of these machines uses a
+compatible convention when returning structures and unions in memory,
+but still returns small structures and unions in registers.
+
+@opindex fpcc-struct-return
+You can tell GCC to use a compatible convention for all structure and
+union returning with the option @option{-fpcc-struct-return}.
+
+@cindex preprocessing tokens
+@cindex preprocessing numbers
+@item
+GCC complains about program fragments such as @samp{0x74ae-0x4000}
+which appear to be two hexadecimal constants separated by the minus
+operator.  Actually, this string is a single @dfn{preprocessing token}.
+Each such token must correspond to one token in C@.  Since this does not,
+GCC prints an error message.  Although it may appear obvious that what
+is meant is an operator and two values, the ISO C standard specifically
+requires that this be treated as erroneous.
+
+A @dfn{preprocessing token} is a @dfn{preprocessing number} if it
+begins with a digit and is followed by letters, underscores, digits,
+periods and @samp{e+}, @samp{e-}, @samp{E+}, @samp{E-}, @samp{p+},
+@samp{p-}, @samp{P+}, or @samp{P-} character sequences.  (In strict C89
+mode, the sequences @samp{p+}, @samp{p-}, @samp{P+} and @samp{P-} cannot
+appear in preprocessing numbers.)
+
+To make the above program fragment valid, place whitespace in front of
+the minus sign.  This whitespace will end the preprocessing number.
+@end itemize
+
+@node Fixed Headers
+@section Fixed Header Files
+
+GCC needs to install corrected versions of some system header files.
+This is because most target systems have some header files that won't
+work with GCC unless they are changed.  Some have bugs, some are
+incompatible with ISO C, and some depend on special features of other
+compilers.
+
+Installing GCC automatically creates and installs the fixed header
+files, by running a program called @code{fixincludes} (or for certain
+targets an alternative such as @code{fixinc.svr4}).  Normally, you
+don't need to pay attention to this.  But there are cases where it
+doesn't do the right thing automatically.
+
+@itemize @bullet
+@item
+If you update the system's header files, such as by installing a new
+system version, the fixed header files of GCC are not automatically
+updated.  The easiest way to update them is to reinstall GCC@.  (If
+you want to be clever, look in the makefile and you can find a
+shortcut.)
+
+@item
+On some systems, in particular SunOS 4, header file directories contain
+machine-specific symbolic links in certain places.  This makes it
+possible to share most of the header files among hosts running the
+same version of SunOS 4 on different machine models.
+
+The programs that fix the header files do not understand this special
+way of using symbolic links; therefore, the directory of fixed header
+files is good only for the machine model used to build it.
+
+In SunOS 4, only programs that look inside the kernel will notice the
+difference between machine models.  Therefore, for most purposes, you
+need not be concerned about this.
+
+It is possible to make separate sets of fixed header files for the
+different machine models, and arrange a structure of symbolic links so
+as to use the proper set, but you'll have to do this by hand.
+
+@item
+On Lynxos, GCC by default does not fix the header files.  This is
+because bugs in the shell cause the @code{fixincludes} script to fail.
+
+This means you will encounter problems due to bugs in the system header
+files.  It may be no comfort that they aren't GCC's fault, but it
+does mean that there's nothing for us to do about them.
+@end itemize
+
+@node Standard Libraries
+@section Standard Libraries
+
+@opindex Wall
+GCC by itself attempts to be a conforming freestanding implementation.
+@xref{Standards,,Language Standards Supported by GCC}, for details of
+what this means.  Beyond the library facilities required of such an
+implementation, the rest of the C library is supplied by the vendor of
+the operating system.  If that C library doesn't conform to the C
+standards, then your programs might get warnings (especially when using
+@option{-Wall}) that you don't expect.
+
+For example, the @code{sprintf} function on SunOS 4.1.3 returns
+@code{char *} while the C standard says that @code{sprintf} returns an
+@code{int}.  The @code{fixincludes} program could make the prototype for
+this function match the Standard, but that would be wrong, since the
+function will still return @code{char *}.
+
+If you need a Standard compliant library, then you need to find one, as
+GCC does not provide one.  The GNU C library (called @code{glibc})
+provides ISO C, POSIX, BSD, SystemV and X/Open compatibility for
+GNU/Linux and HURD-based GNU systems; no recent version of it supports
+other systems, though some very old versions did.  Version 2.2 of the
+GNU C library includes nearly complete C99 support.  You could also ask
+your operating system vendor if newer libraries are available.
+
+@node Disappointments
+@section Disappointments and Misunderstandings
+
+These problems are perhaps regrettable, but we don't know any practical
+way around them.
+
+@itemize @bullet
+@item
+Certain local variables aren't recognized by debuggers when you compile
+with optimization.
+
+This occurs because sometimes GCC optimizes the variable out of
+existence.  There is no way to tell the debugger how to compute the
+value such a variable ``would have had'', and it is not clear that would
+be desirable anyway.  So GCC simply does not mention the eliminated
+variable when it writes debugging information.
+
+You have to expect a certain amount of disagreement between the
+executable and your source code, when you use optimization.
+
+@cindex conflicting types
+@cindex scope of declaration
+@item
+Users often think it is a bug when GCC reports an error for code
+like this:
+
+@example
+int foo (struct mumble *);
+
+struct mumble @{ @dots{} @};
+
+int foo (struct mumble *x)
+@{ @dots{} @}
+@end example
+
+This code really is erroneous, because the scope of @code{struct
+mumble} in the prototype is limited to the argument list containing it.
+It does not refer to the @code{struct mumble} defined with file scope
+immediately below---they are two unrelated types with similar names in
+different scopes.
+
+But in the definition of @code{foo}, the file-scope type is used
+because that is available to be inherited.  Thus, the definition and
+the prototype do not match, and you get an error.
+
+This behavior may seem silly, but it's what the ISO standard specifies.
+It is easy enough for you to make your code work by moving the
+definition of @code{struct mumble} above the prototype.  It's not worth
+being incompatible with ISO C just to avoid an error for the example
+shown above.
+
+@item
+Accesses to bit-fields even in volatile objects works by accessing larger
+objects, such as a byte or a word.  You cannot rely on what size of
+object is accessed in order to read or write the bit-field; it may even
+vary for a given bit-field according to the precise usage.
+
+If you care about controlling the amount of memory that is accessed, use
+volatile but do not use bit-fields.
+
+@item
+GCC comes with shell scripts to fix certain known problems in system
+header files.  They install corrected copies of various header files in
+a special directory where only GCC will normally look for them.  The
+scripts adapt to various systems by searching all the system header
+files for the problem cases that we know about.
+
+If new system header files are installed, nothing automatically arranges
+to update the corrected header files.  You will have to reinstall GCC
+to fix the new header files.  More specifically, go to the build
+directory and delete the files @file{stmp-fixinc} and
+@file{stmp-headers}, and the subdirectory @code{include}; then do
+@samp{make install} again.
+
+@item
+@cindex floating point precision
+On 68000 and x86 systems, for instance, you can get paradoxical results
+if you test the precise values of floating point numbers.  For example,
+you can find that a floating point value which is not a NaN is not equal
+to itself.  This results from the fact that the floating point registers
+hold a few more bits of precision than fit in a @code{double} in memory.
+Compiled code moves values between memory and floating point registers
+at its convenience, and moving them into memory truncates them.
+
+@opindex ffloat-store
+You can partially avoid this problem by using the @option{-ffloat-store}
+option (@pxref{Optimize Options}).
+
+@item
+On the MIPS, variable argument functions using @file{varargs.h}
+cannot have a floating point value for the first argument.  The
+reason for this is that in the absence of a prototype in scope,
+if the first argument is a floating point, it is passed in a
+floating point register, rather than an integer register.
+
+If the code is rewritten to use the ISO standard @file{stdarg.h}
+method of variable arguments, and the prototype is in scope at
+the time of the call, everything will work fine.
+
+@item
+On the H8/300 and H8/300H, variable argument functions must be
+implemented using the ISO standard @file{stdarg.h} method of
+variable arguments.  Furthermore, calls to functions using @file{stdarg.h}
+variable arguments must have a prototype for the called function
+in scope at the time of the call.
+
+@item
+On AIX and other platforms without weak symbol support, templates
+need to be instantiated explicitly and symbols for static members
+of templates will not be generated.
+@end itemize
+
+@node C++ Misunderstandings
+@section Common Misunderstandings with GNU C++
+
+@cindex misunderstandings in C++
+@cindex surprises in C++
+@cindex C++ misunderstandings
+C++ is a complex language and an evolving one, and its standard
+definition (the ISO C++ standard) was only recently completed.  As a
+result, your C++ compiler may occasionally surprise you, even when its
+behavior is correct.  This section discusses some areas that frequently
+give rise to questions of this sort.
+
+@menu
+* Static Definitions::  Static member declarations are not definitions
+* Temporaries::         Temporaries may vanish before you expect
+* Copy Assignment::     Copy Assignment operators copy virtual bases twice
+@end menu
+
+@node Static Definitions
+@subsection Declare @emph{and} Define Static Members
+
+@cindex C++ static data, declaring and defining
+@cindex static data in C++, declaring and defining
+@cindex declaring static data in C++
+@cindex defining static data in C++
+When a class has static data members, it is not enough to @emph{declare}
+the static member; you must also @emph{define} it.  For example:
+
+@example
+class Foo
+@{
+  @dots{}
+  void method();
+  static int bar;
+@};
+@end example
+
+This declaration only establishes that the class @code{Foo} has an
+@code{int} named @code{Foo::bar}, and a member function named
+@code{Foo::method}.  But you still need to define @emph{both}
+@code{method} and @code{bar} elsewhere.  According to the ISO
+standard, you must supply an initializer in one (and only one) source
+file, such as:
+
+@example
+int Foo::bar = 0;
+@end example
+
+Other C++ compilers may not correctly implement the standard behavior.
+As a result, when you switch to @code{g++} from one of these compilers,
+you may discover that a program that appeared to work correctly in fact
+does not conform to the standard: @code{g++} reports as undefined
+symbols any static data members that lack definitions.
+
+@node Temporaries
+@subsection Temporaries May Vanish Before You Expect
+
+@cindex temporaries, lifetime of
+@cindex portions of temporary objects, pointers to
+It is dangerous to use pointers or references to @emph{portions} of a
+temporary object.  The compiler may very well delete the object before
+you expect it to, leaving a pointer to garbage.  The most common place
+where this problem crops up is in classes like string classes,
+especially ones that define a conversion function to type @code{char *}
+or @code{const char *}---which is one reason why the standard
+@code{string} class requires you to call the @code{c_str} member
+function.  However, any class that returns a pointer to some internal
+structure is potentially subject to this problem.
+
+For example, a program may use a function @code{strfunc} that returns
+@code{string} objects, and another function @code{charfunc} that
+operates on pointers to @code{char}:
+
+@example
+string strfunc ();
+void charfunc (const char *);
+
+void
+f ()
+@{
+  const char *p = strfunc().c_str();
+  @dots{}
+  charfunc (p);
+  @dots{}
+  charfunc (p);
+@}
+@end example
+
+@noindent
+In this situation, it may seem reasonable to save a pointer to the C
+string returned by the @code{c_str} member function and use that rather
+than call @code{c_str} repeatedly.  However, the temporary string
+created by the call to @code{strfunc} is destroyed after @code{p} is
+initialized, at which point @code{p} is left pointing to freed memory.
+
+Code like this may run successfully under some other compilers,
+particularly obsolete cfront-based compilers that delete temporaries
+along with normal local variables.  However, the GNU C++ behavior is
+standard-conforming, so if your program depends on late destruction of
+temporaries it is not portable.
+
+The safe way to write such code is to give the temporary a name, which
+forces it to remain until the end of the scope of the name.  For
+example:
+
+@example
+string& tmp = strfunc ();
+charfunc (tmp.c_str ());
+@end example
+
+@node Copy Assignment
+@subsection Implicit Copy-Assignment for Virtual Bases
+
+When a base class is virtual, only one subobject of the base class
+belongs to each full object.  Also, the constructors and destructors are
+invoked only once, and called from the most-derived class.  However, such
+objects behave unspecified when being assigned.  For example:
+
+@example
+struct Base@{
+  char *name;
+  Base(char *n) : name(strdup(n))@{@}
+  Base& operator= (const Base& other)@{
+   free (name);
+   name = strdup (other.name);
+  @}
+@};
+
+struct A:virtual Base@{
+  int val;
+  A():Base("A")@{@}
+@};
+
+struct B:virtual Base@{
+  int bval;
+  B():Base("B")@{@}
+@};
+
+struct Derived:public A, public B@{
+  Derived():Base("Derived")@{@}
+@};
+
+void func(Derived &d1, Derived &d2)
+@{
+  d1 = d2;
+@}
+@end example
+
+The C++ standard specifies that @samp{Base::Base} is only called once
+when constructing or copy-constructing a Derived object.  It is
+unspecified whether @samp{Base::operator=} is called more than once when
+the implicit copy-assignment for Derived objects is invoked (as it is
+inside @samp{func} in the example).
+
+g++ implements the ``intuitive'' algorithm for copy-assignment: assign all
+direct bases, then assign all members.  In that algorithm, the virtual
+base subobject can be encountered many times.  In the example, copying
+proceeds in the following order: @samp{val}, @samp{name} (via
+@code{strdup}), @samp{bval}, and @samp{name} again.
+
+If application code relies on copy-assignment, a user-defined
+copy-assignment operator removes any uncertainties.  With such an
+operator, the application can define whether and how the virtual base
+subobject is assigned.
+
+@node Protoize Caveats
+@section Caveats of using @command{protoize}
+
+The conversion programs @command{protoize} and @command{unprotoize} can
+sometimes change a source file in a way that won't work unless you
+rearrange it.
+
+@itemize @bullet
+@item
+@command{protoize} can insert references to a type name or type tag before
+the definition, or in a file where they are not defined.
+
+If this happens, compiler error messages should show you where the new
+references are, so fixing the file by hand is straightforward.
+
+@item
+There are some C constructs which @command{protoize} cannot figure out.
+For example, it can't determine argument types for declaring a
+pointer-to-function variable; this you must do by hand.  @command{protoize}
+inserts a comment containing @samp{???} each time it finds such a
+variable; so you can find all such variables by searching for this
+string.  ISO C does not require declaring the argument types of
+pointer-to-function types.
+
+@item
+Using @command{unprotoize} can easily introduce bugs.  If the program
+relied on prototypes to bring about conversion of arguments, these
+conversions will not take place in the program without prototypes.
+One case in which you can be sure @command{unprotoize} is safe is when
+you are removing prototypes that were made with @command{protoize}; if
+the program worked before without any prototypes, it will work again
+without them.
+
+@opindex Wconversion
+You can find all the places where this problem might occur by compiling
+the program with the @option{-Wconversion} option.  It prints a warning
+whenever an argument is converted.
+
+@item
+Both conversion programs can be confused if there are macro calls in and
+around the text to be converted.  In other words, the standard syntax
+for a declaration or definition must not result from expanding a macro.
+This problem is inherent in the design of C and cannot be fixed.  If
+only a few functions have confusing macro calls, you can easily convert
+them manually.
+
+@item
+@command{protoize} cannot get the argument types for a function whose
+definition was not actually compiled due to preprocessing conditionals.
+When this happens, @command{protoize} changes nothing in regard to such
+a function.  @command{protoize} tries to detect such instances and warn
+about them.
+
+You can generally work around this problem by using @command{protoize} step
+by step, each time specifying a different set of @option{-D} options for
+compilation, until all of the functions have been converted.  There is
+no automatic way to verify that you have got them all, however.
+
+@item
+Confusion may result if there is an occasion to convert a function
+declaration or definition in a region of source code where there is more
+than one formal parameter list present.  Thus, attempts to convert code
+containing multiple (conditionally compiled) versions of a single
+function header (in the same vicinity) may not produce the desired (or
+expected) results.
+
+If you plan on converting source files which contain such code, it is
+recommended that you first make sure that each conditionally compiled
+region of source code which contains an alternative function header also
+contains at least one additional follower token (past the final right
+parenthesis of the function header).  This should circumvent the
+problem.
+
+@item
+@command{unprotoize} can become confused when trying to convert a function
+definition or declaration which contains a declaration for a
+pointer-to-function formal argument which has the same name as the
+function being defined or declared.  We recommend you avoid such choices
+of formal parameter names.
+
+@item
+You might also want to correct some of the indentation by hand and break
+long lines.  (The conversion programs don't write lines longer than
+eighty characters in any case.)
+@end itemize
+
+@node Non-bugs
+@section Certain Changes We Don't Want to Make
+
+This section lists changes that people frequently request, but which
+we do not make because we think GCC is better without them.
+
+@itemize @bullet
+@item
+Checking the number and type of arguments to a function which has an
+old-fashioned definition and no prototype.
+
+Such a feature would work only occasionally---only for calls that appear
+in the same file as the called function, following the definition.  The
+only way to check all calls reliably is to add a prototype for the
+function.  But adding a prototype eliminates the motivation for this
+feature.  So the feature is not worthwhile.
+
+@item
+Warning about using an expression whose type is signed as a shift count.
+
+Shift count operands are probably signed more often than unsigned.
+Warning about this would cause far more annoyance than good.
+
+@item
+Warning about assigning a signed value to an unsigned variable.
+
+Such assignments must be very common; warning about them would cause
+more annoyance than good.
+
+@item
+Warning when a non-void function value is ignored.
+
+Coming as I do from a Lisp background, I balk at the idea that there is
+something dangerous about discarding a value.  There are functions that
+return values which some callers may find useful; it makes no sense to
+clutter the program with a cast to @code{void} whenever the value isn't
+useful.
+
+@item
+@opindex fshort-enums
+Making @option{-fshort-enums} the default.
+
+This would cause storage layout to be incompatible with most other C
+compilers.  And it doesn't seem very important, given that you can get
+the same result in other ways.  The case where it matters most is when
+the enumeration-valued object is inside a structure, and in that case
+you can specify a field width explicitly.
+
+@item
+Making bit-fields unsigned by default on particular machines where ``the
+ABI standard'' says to do so.
+
+The ISO C standard leaves it up to the implementation whether a bit-field
+declared plain @code{int} is signed or not.  This in effect creates two
+alternative dialects of C@.
+
+@opindex fsigned-bitfields
+@opindex funsigned-bitfields
+The GNU C compiler supports both dialects; you can specify the signed
+dialect with @option{-fsigned-bitfields} and the unsigned dialect with
+@option{-funsigned-bitfields}.  However, this leaves open the question of
+which dialect to use by default.
+
+Currently, the preferred dialect makes plain bit-fields signed, because
+this is simplest.  Since @code{int} is the same as @code{signed int} in
+every other context, it is cleanest for them to be the same in bit-fields
+as well.
+
+Some computer manufacturers have published Application Binary Interface
+standards which specify that plain bit-fields should be unsigned.  It is
+a mistake, however, to say anything about this issue in an ABI@.  This is
+because the handling of plain bit-fields distinguishes two dialects of C@.
+Both dialects are meaningful on every type of machine.  Whether a
+particular object file was compiled using signed bit-fields or unsigned
+is of no concern to other object files, even if they access the same
+bit-fields in the same data structures.
+
+A given program is written in one or the other of these two dialects.
+The program stands a chance to work on most any machine if it is
+compiled with the proper dialect.  It is unlikely to work at all if
+compiled with the wrong dialect.
+
+Many users appreciate the GNU C compiler because it provides an
+environment that is uniform across machines.  These users would be
+inconvenienced if the compiler treated plain bit-fields differently on
+certain machines.
+
+Occasionally users write programs intended only for a particular machine
+type.  On these occasions, the users would benefit if the GNU C compiler
+were to support by default the same dialect as the other compilers on
+that machine.  But such applications are rare.  And users writing a
+program to run on more than one type of machine cannot possibly benefit
+from this kind of compatibility.
+
+This is why GCC does and will treat plain bit-fields in the same
+fashion on all types of machines (by default).
+
+There are some arguments for making bit-fields unsigned by default on all
+machines.  If, for example, this becomes a universal de facto standard,
+it would make sense for GCC to go along with it.  This is something
+to be considered in the future.
+
+(Of course, users strongly concerned about portability should indicate
+explicitly in each bit-field whether it is signed or not.  In this way,
+they write programs which have the same meaning in both C dialects.)
+
+@item
+@opindex ansi
+@opindex traditional
+@opindex std
+Undefining @code{__STDC__} when @option{-ansi} is not used.
+
+Currently, GCC defines @code{__STDC__} as long as you don't use
+@option{-traditional}.  This provides good results in practice.
+
+Programmers normally use conditionals on @code{__STDC__} to ask whether
+it is safe to use certain features of ISO C, such as function
+prototypes or ISO token concatenation.  Since plain @command{gcc} supports
+all the features of ISO C, the correct answer to these questions is
+``yes''.
+
+Some users try to use @code{__STDC__} to check for the availability of
+certain library facilities.  This is actually incorrect usage in an ISO
+C program, because the ISO C standard says that a conforming
+freestanding implementation should define @code{__STDC__} even though it
+does not have the library facilities.  @samp{gcc -ansi -pedantic} is a
+conforming freestanding implementation, and it is therefore required to
+define @code{__STDC__}, even though it does not come with an ISO C
+library.
+
+Sometimes people say that defining @code{__STDC__} in a compiler that
+does not completely conform to the ISO C standard somehow violates the
+standard.  This is illogical.  The standard is a standard for compilers
+that claim to support ISO C, such as @samp{gcc -ansi}---not for other
+compilers such as plain @command{gcc}.  Whatever the ISO C standard says
+is relevant to the design of plain @command{gcc} without @option{-ansi} only
+for pragmatic reasons, not as a requirement.
+
+GCC normally defines @code{__STDC__} to be 1, and in addition
+defines @code{__STRICT_ANSI__} if you specify the @option{-ansi} option,
+or a @option{-std} option for strict conformance to some version of ISO C@.
+On some hosts, system include files use a different convention, where
+@code{__STDC__} is normally 0, but is 1 if the user specifies strict
+conformance to the C Standard.  GCC follows the host convention when
+processing system include files, but when processing user files it follows
+the usual GNU C convention.
+
+@item
+Undefining @code{__STDC__} in C++.
+
+Programs written to compile with C++-to-C translators get the
+value of @code{__STDC__} that goes with the C compiler that is
+subsequently used.  These programs must test @code{__STDC__}
+to determine what kind of C preprocessor that compiler uses:
+whether they should concatenate tokens in the ISO C fashion
+or in the traditional fashion.
+
+These programs work properly with GNU C++ if @code{__STDC__} is defined.
+They would not work otherwise.
+
+In addition, many header files are written to provide prototypes in ISO
+C but not in traditional C@.  Many of these header files can work without
+change in C++ provided @code{__STDC__} is defined.  If @code{__STDC__}
+is not defined, they will all fail, and will all need to be changed to
+test explicitly for C++ as well.
+
+@item
+Deleting ``empty'' loops.
+
+Historically, GCC has not deleted ``empty'' loops under the
+assumption that the most likely reason you would put one in a program is
+to have a delay, so deleting them will not make real programs run any
+faster.
+
+However, the rationale here is that optimization of a nonempty loop
+cannot produce an empty one, which holds for C but is not always the
+case for C++.
+
+@opindex funroll-loops
+Moreover, with @option{-funroll-loops} small ``empty'' loops are already
+removed, so the current behavior is both sub-optimal and inconsistent
+and will change in the future.
+
+@item
+Making side effects happen in the same order as in some other compiler.
+
+@cindex side effects, order of evaluation
+@cindex order of evaluation, side effects
+It is never safe to depend on the order of evaluation of side effects.
+For example, a function call like this may very well behave differently
+from one compiler to another:
+
+@example
+void func (int, int);
+
+int i = 2;
+func (i++, i++);
+@end example
+
+There is no guarantee (in either the C or the C++ standard language
+definitions) that the increments will be evaluated in any particular
+order.  Either increment might happen first.  @code{func} might get the
+arguments @samp{2, 3}, or it might get @samp{3, 2}, or even @samp{2, 2}.
+
+@item
+Not allowing structures with volatile fields in registers.
+
+Strictly speaking, there is no prohibition in the ISO C standard
+against allowing structures with volatile fields in registers, but
+it does not seem to make any sense and is probably not what you wanted
+to do.  So the compiler will give an error message in this case.
+
+@item
+Making certain warnings into errors by default.
+
+Some ISO C testsuites report failure when the compiler does not produce
+an error message for a certain program.
+
+@opindex pedantic-errors
+ISO C requires a ``diagnostic'' message for certain kinds of invalid
+programs, but a warning is defined by GCC to count as a diagnostic.  If
+GCC produces a warning but not an error, that is correct ISO C support.
+If test suites call this ``failure'', they should be run with the GCC
+option @option{-pedantic-errors}, which will turn these warnings into
+errors.
+
+@end itemize
+
+@node Warnings and Errors
+@section Warning Messages and Error Messages
+
+@cindex error messages
+@cindex warnings vs errors
+@cindex messages, warning and error
+The GNU compiler can produce two kinds of diagnostics: errors and
+warnings.  Each kind has a different purpose:
+
+@itemize @w{}
+@item
+@dfn{Errors} report problems that make it impossible to compile your
+program.  GCC reports errors with the source file name and line
+number where the problem is apparent.
+
+@item
+@dfn{Warnings} report other unusual conditions in your code that
+@emph{may} indicate a problem, although compilation can (and does)
+proceed.  Warning messages also report the source file name and line
+number, but include the text @samp{warning:} to distinguish them
+from error messages.
+@end itemize
+
+Warnings may indicate danger points where you should check to make sure
+that your program really does what you intend; or the use of obsolete
+features; or the use of nonstandard features of GNU C or C++.  Many
+warnings are issued only if you ask for them, with one of the @option{-W}
+options (for instance, @option{-Wall} requests a variety of useful
+warnings).
+
+@opindex pedantic
+@opindex pedantic-errors
+GCC always tries to compile your program if possible; it never
+gratuitously rejects a program whose meaning is clear merely because
+(for instance) it fails to conform to a standard.  In some cases,
+however, the C and C++ standards specify that certain extensions are
+forbidden, and a diagnostic @emph{must} be issued by a conforming
+compiler.  The @option{-pedantic} option tells GCC to issue warnings in
+such cases; @option{-pedantic-errors} says to make them errors instead.
+This does not mean that @emph{all} non-ISO constructs get warnings
+or errors.
+
+@xref{Warning Options,,Options to Request or Suppress Warnings}, for
+more detail on these and related command-line options.
diff --git a/contrib/gcc/doc/vms.texi b/contrib/gcc/doc/vms.texi
new file mode 100644
index 0000000..5ab2666
--- /dev/null
+++ b/contrib/gcc/doc/vms.texi
@@ -0,0 +1,331 @@
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+@c 1999, 2000, 2001 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node VMS
+@chapter Using GCC on VMS
+
+@c prevent bad page break with this line
+Here is how to use GCC on VMS@.
+
+@menu
+* Include Files and VMS::  Where the preprocessor looks for the include files.
+* Global Declarations::    How to do globaldef, globalref and globalvalue with
+                           GCC.
+* VMS Misc::		   Misc information.
+@end menu
+
+@node Include Files and VMS
+@section Include Files and VMS
+
+@cindex include files and VMS
+@cindex VMS and include files
+@cindex header files and VMS
+Due to the differences between the filesystems of Unix and VMS, GCC
+attempts to translate file names in @samp{#include} into names that VMS
+will understand.  The basic strategy is to prepend a prefix to the
+specification of the include file, convert the whole filename to a VMS
+filename, and then try to open the file.  GCC tries various prefixes
+one by one until one of them succeeds:
+
+@enumerate
+@item
+The first prefix is the @samp{GNU_CC_INCLUDE:} logical name: this is
+where GNU C header files are traditionally stored.  If you wish to store
+header files in non-standard locations, then you can assign the logical
+@samp{GNU_CC_INCLUDE} to be a search list, where each element of the
+list is suitable for use with a rooted logical.
+
+@item
+The next prefix tried is @samp{SYS$SYSROOT:[SYSLIB.]}.  This is where
+VAX-C header files are traditionally stored.
+
+@item
+If the include file specification by itself is a valid VMS filename, the
+preprocessor then uses this name with no prefix in an attempt to open
+the include file.
+
+@item
+If the file specification is not a valid VMS filename (i.e.@: does not
+contain a device or a directory specifier, and contains a @samp{/}
+character), the preprocessor tries to convert it from Unix syntax to
+VMS syntax.
+
+Conversion works like this: the first directory name becomes a device,
+and the rest of the directories are converted into VMS-format directory
+names.  For example, the name @file{X11/foobar.h} is
+translated to @file{X11:[000000]foobar.h} or @file{X11:foobar.h},
+whichever one can be opened.  This strategy allows you to assign a
+logical name to point to the actual location of the header files.
+
+@item
+If none of these strategies succeeds, the @samp{#include} fails.
+@end enumerate
+
+Include directives of the form:
+
+@example
+#include foobar
+@end example
+
+@noindent
+are a common source of incompatibility between VAX-C and GCC@.  VAX-C
+treats this much like a standard @code{#include <foobar.h>} directive.
+That is incompatible with the ISO C behavior implemented by GCC: to
+expand the name @code{foobar} as a macro.  Macro expansion should
+eventually yield one of the two standard formats for @code{#include}:
+
+@example
+#include "@var{file}"
+#include <@var{file}>
+@end example
+
+If you have this problem, the best solution is to modify the source to
+convert the @code{#include} directives to one of the two standard forms.
+That will work with either compiler.  If you want a quick and dirty fix,
+define the file names as macros with the proper expansion, like this:
+
+@example
+#define stdio <stdio.h>
+@end example
+
+@noindent
+This will work, as long as the name doesn't conflict with anything else
+in the program.
+
+Another source of incompatibility is that VAX-C assumes that:
+
+@example
+#include "foobar"
+@end example
+
+@noindent
+is actually asking for the file @file{foobar.h}.  GCC does not
+make this assumption, and instead takes what you ask for literally;
+it tries to read the file @file{foobar}.  The best way to avoid this
+problem is to always specify the desired file extension in your include
+directives.
+
+GCC for VMS is distributed with a set of include files that is
+sufficient to compile most general purpose programs.  Even though the
+GCC distribution does not contain header files to define constants
+and structures for some VMS system-specific functions, there is no
+reason why you cannot use GCC with any of these functions.  You first
+may have to generate or create header files, either by using the public
+domain utility @code{UNSDL} (which can be found on a DECUS tape), or by
+extracting the relevant modules from one of the system macro libraries,
+and using an editor to construct a C header file.
+
+A @code{#include} file name cannot contain a DECNET node name.  The
+preprocessor reports an I/O error if you attempt to use a node name,
+whether explicitly, or implicitly via a logical name.
+
+@node Global Declarations
+@section Global Declarations and VMS
+
+@findex GLOBALREF
+@findex GLOBALDEF
+@findex GLOBALVALUEDEF
+@findex GLOBALVALUEREF
+GCC does not provide the @code{globalref}, @code{globaldef} and
+@code{globalvalue} keywords of VAX-C@.  You can get the same effect with
+an obscure feature of GAS, the GNU assembler.  (This requires GAS
+version 1.39 or later.)  The following macros allow you to use this
+feature in a fairly natural way:
+
+@smallexample
+#ifdef __GNUC__
+#define GLOBALREF(TYPE,NAME)                      \
+  TYPE NAME                                       \
+  asm ("_$$PsectAttributes_GLOBALSYMBOL$$" #NAME)
+#define GLOBALDEF(TYPE,NAME,VALUE)                \
+  TYPE NAME                                       \
+  asm ("_$$PsectAttributes_GLOBALSYMBOL$$" #NAME) \
+    = VALUE
+#define GLOBALVALUEREF(TYPE,NAME)                 \
+  const TYPE NAME[1]                              \
+  asm ("_$$PsectAttributes_GLOBALVALUE$$" #NAME)
+#define GLOBALVALUEDEF(TYPE,NAME,VALUE)           \
+  const TYPE NAME[1]                              \
+  asm ("_$$PsectAttributes_GLOBALVALUE$$" #NAME)  \
+    = @{VALUE@}
+#else
+#define GLOBALREF(TYPE,NAME) \
+  globalref TYPE NAME
+#define GLOBALDEF(TYPE,NAME,VALUE) \
+  globaldef TYPE NAME = VALUE
+#define GLOBALVALUEDEF(TYPE,NAME,VALUE) \
+  globalvalue TYPE NAME = VALUE
+#define GLOBALVALUEREF(TYPE,NAME) \
+  globalvalue TYPE NAME
+#endif
+@end smallexample
+
+@noindent
+(The @code{_$$PsectAttributes_GLOBALSYMBOL} prefix at the start of the
+name is removed by the assembler, after it has modified the attributes
+of the symbol).  These macros are provided in the VMS binaries
+distribution in a header file @file{GNU_HACKS.H}.  An example of the
+usage is:
+
+@example
+GLOBALREF (int, ijk);
+GLOBALDEF (int, jkl, 0);
+@end example
+
+The macros @code{GLOBALREF} and @code{GLOBALDEF} cannot be used
+straightforwardly for arrays, since there is no way to insert the array
+dimension into the declaration at the right place.  However, you can
+declare an array with these macros if you first define a typedef for the
+array type, like this:
+
+@example
+typedef int intvector[10];
+GLOBALREF (intvector, foo);
+@end example
+
+Array and structure initializers will also break the macros; you can
+define the initializer to be a macro of its own, or you can expand the
+@code{GLOBALDEF} macro by hand.  You may find a case where you wish to
+use the @code{GLOBALDEF} macro with a large array, but you are not
+interested in explicitly initializing each element of the array.  In
+such cases you can use an initializer like: @code{@{0,@}}, which will
+initialize the entire array to @code{0}.
+
+A shortcoming of this implementation is that a variable declared with
+@code{GLOBALVALUEREF} or @code{GLOBALVALUEDEF} is always an array.  For
+example, the declaration:
+
+@example
+GLOBALVALUEREF(int, ijk);
+@end example
+
+@noindent
+declares the variable @code{ijk} as an array of type @code{int [1]}.
+This is done because a globalvalue is actually a constant; its ``value''
+is what the linker would normally consider an address.  That is not how
+an integer value works in C, but it is how an array works.  So treating
+the symbol as an array name gives consistent results---with the
+exception that the value seems to have the wrong type.  @strong{Don't
+try to access an element of the array.}  It doesn't have any elements.
+The array ``address'' may not be the address of actual storage.
+
+The fact that the symbol is an array may lead to warnings where the
+variable is used.  Insert type casts to avoid the warnings.  Here is an
+example; it takes advantage of the ISO C feature allowing macros that
+expand to use the same name as the macro itself.
+
+@example
+GLOBALVALUEREF (int, ss$_normal);
+GLOBALVALUEDEF (int, xyzzy,123);
+#ifdef __GNUC__
+#define ss$_normal ((int) ss$_normal)
+#define xyzzy ((int) xyzzy)
+#endif
+@end example
+
+Don't use @code{globaldef} or @code{globalref} with a variable whose
+type is an enumeration type; this is not implemented.  Instead, make the
+variable an integer, and use a @code{globalvaluedef} for each of the
+enumeration values.  An example of this would be:
+
+@example
+#ifdef __GNUC__
+GLOBALDEF (int, color, 0);
+GLOBALVALUEDEF (int, RED, 0);
+GLOBALVALUEDEF (int, BLUE, 1);
+GLOBALVALUEDEF (int, GREEN, 3);
+#else
+enum globaldef color @{RED, BLUE, GREEN = 3@};
+#endif
+@end example
+
+@node VMS Misc
+@section Other VMS Issues
+
+@cindex exit status and VMS
+@cindex return value of @code{main}
+@cindex @code{main} and the exit status
+GCC automatically arranges for @code{main} to return 1 by default if
+you fail to specify an explicit return value.  This will be interpreted
+by VMS as a status code indicating a normal successful completion.
+Version 1 of GCC did not provide this default.
+
+GCC on VMS works only with the GNU assembler, GAS@.  You need version
+1.37 or later of GAS in order to produce value debugging information for
+the VMS debugger.  Use the ordinary VMS linker with the object files
+produced by GAS@.
+
+@cindex shared VMS run time system
+@cindex @file{VAXCRTL}
+Under previous versions of GCC, the generated code would occasionally
+give strange results when linked to the sharable @file{VAXCRTL} library.
+Now this should work.
+
+A caveat for use of @code{const} global variables: the @code{const}
+modifier must be specified in every external declaration of the variable
+in all of the source files that use that variable.  Otherwise the linker
+will issue warnings about conflicting attributes for the variable.  Your
+program will still work despite the warnings, but the variable will be
+placed in writable storage.
+
+@cindex name augmentation
+@cindex case sensitivity and VMS
+@cindex VMS and case sensitivity
+Although the VMS linker does distinguish between upper and lower case
+letters in global symbols, most VMS compilers convert all such symbols
+into upper case and most run-time library routines also have upper case
+names.  To be able to reliably call such routines, GCC (by means of
+the assembler GAS) converts global symbols into upper case like other
+VMS compilers.  However, since the usual practice in C is to distinguish
+case, GCC (via GAS) tries to preserve usual C behavior by augmenting
+each name that is not all lower case.  This means truncating the name
+to at most 23 characters and then adding more characters at the end
+which encode the case pattern of those 23.   Names which contain at
+least one dollar sign are an exception; they are converted directly into
+upper case without augmentation.
+
+Name augmentation yields bad results for programs that use precompiled
+libraries (such as Xlib) which were generated by another compiler.  You
+can use the compiler option @samp{/NOCASE_HACK} to inhibit augmentation;
+it makes external C functions and variables case-independent as is usual
+on VMS@.  Alternatively, you could write all references to the functions
+and variables in such libraries using lower case; this will work on VMS,
+but is not portable to other systems.  The compiler option @samp{/NAMES}
+also provides control over global name handling.
+
+Function and variable names are handled somewhat differently with G++.
+The GNU C++ compiler performs @dfn{name mangling} on function
+names, which means that it adds information to the function name to
+describe the data types of the arguments that the function takes.  One
+result of this is that the name of a function can become very long.
+Since the VMS linker only recognizes the first 31 characters in a name,
+special action is taken to ensure that each function and variable has a
+unique name that can be represented in 31 characters.
+
+If the name (plus a name augmentation, if required) is less than 32
+characters in length, then no special action is performed.  If the name
+is longer than 31 characters, the assembler (GAS) will generate a
+hash string based upon the function name, truncate the function name to
+23 characters, and append the hash string to the truncated name.  If the
+@samp{/VERBOSE} compiler option is used, the assembler will print both
+the full and truncated names of each symbol that is truncated.
+
+The @samp{/NOCASE_HACK} compiler option should not be used when you are
+compiling programs that use libg++.  libg++ has several instances of
+objects (i.e.  @code{Filebuf} and @code{filebuf}) which become
+indistinguishable in a case-insensitive environment.  This leads to
+cases where you need to inhibit augmentation selectively (if you were
+using libg++ and Xlib in the same program, for example).  There is no
+special feature for doing this, but you can get the result by defining a
+macro for each mixed case symbol for which you wish to inhibit
+augmentation.  The macro should expand into the lower case equivalent of
+itself.  For example:
+
+@example
+#define StuDlyCapS studlycaps
+@end example
+
+These macro definitions can be placed in a header file to minimize the
+number of changes to your source code.