Vendor import of llvm trunk r161861:

http://llvm.org/svn/llvm-project/llvm/trunk@161861

1 files changed, 251 insertions, 0 deletions

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+llc - LLVM static compiler
+==========================
+
+
+SYNOPSIS
+--------
+
+
+**llc** [*options*] [*filename*]
+
+
+DESCRIPTION
+-----------
+
+
+The **llc** command compiles LLVM source inputs into assembly language for a
+specified architecture.  The assembly language output can then be passed through
+a native assembler and linker to generate a native executable.
+
+The choice of architecture for the output assembly code is automatically
+determined from the input file, unless the **-march** option is used to override
+the default.
+
+
+OPTIONS
+-------
+
+
+If *filename* is - or omitted, **llc** reads from standard input.  Otherwise, it
+will from *filename*.  Inputs can be in either the LLVM assembly language
+format (.ll) or the LLVM bitcode format (.bc).
+
+If the **-o** option is omitted, then **llc** will send its output to standard
+output if the input is from standard input.  If the **-o** option specifies -,
+then the output will also be sent to standard output.
+
+If no **-o** option is specified and an input file other than - is specified,
+then **llc** creates the output filename by taking the input filename,
+removing any existing *.bc* extension, and adding a *.s* suffix.
+
+Other **llc** options are as follows:
+
+End-user Options
+~~~~~~~~~~~~~~~~
+
+
+
+**-help**
+
+ Print a summary of command line options.
+
+
+
+**-O**\ =\ *uint*
+
+ Generate code at different optimization levels. These correspond to the *-O0*,
+ *-O1*, *-O2*, and *-O3* optimization levels used by **llvm-gcc** and
+ **clang**.
+
+
+
+**-mtriple**\ =\ *target triple*
+
+ Override the target triple specified in the input file with the specified
+ string.
+
+
+
+**-march**\ =\ *arch*
+
+ Specify the architecture for which to generate assembly, overriding the target
+ encoded in the input file.  See the output of **llc -help** for a list of
+ valid architectures.  By default this is inferred from the target triple or
+ autodetected to the current architecture.
+
+
+
+**-mcpu**\ =\ *cpuname*
+
+ Specify a specific chip in the current architecture to generate code for.
+ By default this is inferred from the target triple and autodetected to
+ the current architecture.  For a list of available CPUs, use:
+ **llvm-as < /dev/null | llc -march=xyz -mcpu=help**
+
+
+
+**-mattr**\ =\ *a1,+a2,-a3,...*
+
+ Override or control specific attributes of the target, such as whether SIMD
+ operations are enabled or not.  The default set of attributes is set by the
+ current CPU.  For a list of available attributes, use:
+ **llvm-as < /dev/null | llc -march=xyz -mattr=help**
+
+
+
+**--disable-fp-elim**
+
+ Disable frame pointer elimination optimization.
+
+
+
+**--disable-excess-fp-precision**
+
+ Disable optimizations that may produce excess precision for floating point.
+ Note that this option can dramatically slow down code on some systems
+ (e.g. X86).
+
+
+
+**--enable-no-infs-fp-math**
+
+ Enable optimizations that assume no Inf values.
+
+
+
+**--enable-no-nans-fp-math**
+
+ Enable optimizations that assume no NAN values.
+
+
+
+**--enable-unsafe-fp-math**
+
+ Enable optimizations that make unsafe assumptions about IEEE math (e.g. that
+ addition is associative) or may not work for all input ranges.  These
+ optimizations allow the code generator to make use of some instructions which
+ would otherwise not be usable (such as fsin on X86).
+
+
+
+**--enable-correct-eh-support**
+
+ Instruct the **lowerinvoke** pass to insert code for correct exception handling
+ support.  This is expensive and is by default omitted for efficiency.
+
+
+
+**--stats**
+
+ Print statistics recorded by code-generation passes.
+
+
+
+**--time-passes**
+
+ Record the amount of time needed for each pass and print a report to standard
+ error.
+
+
+
+**--load**\ =\ *dso_path*
+
+ Dynamically load *dso_path* (a path to a dynamically shared object) that
+ implements an LLVM target. This will permit the target name to be used with the
+ **-march** option so that code can be generated for that target.
+
+
+
+
+Tuning/Configuration Options
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+
+
+**--print-machineinstrs**
+
+ Print generated machine code between compilation phases (useful for debugging).
+
+
+
+**--regalloc**\ =\ *allocator*
+
+ Specify the register allocator to use. The default *allocator* is *local*.
+ Valid register allocators are:
+
+
+ *simple*
+
+  Very simple "always spill" register allocator
+
+
+
+ *local*
+
+  Local register allocator
+
+
+
+ *linearscan*
+
+  Linear scan global register allocator
+
+
+
+ *iterativescan*
+
+  Iterative scan global register allocator
+
+
+
+
+
+**--spiller**\ =\ *spiller*
+
+ Specify the spiller to use for register allocators that support it.  Currently
+ this option is used only by the linear scan register allocator. The default
+ *spiller* is *local*.  Valid spillers are:
+
+
+ *simple*
+
+  Simple spiller
+
+
+
+ *local*
+
+  Local spiller
+
+
+
+
+
+
+Intel IA-32-specific Options
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+
+
+**--x86-asm-syntax=att|intel**
+
+ Specify whether to emit assembly code in AT&T syntax (the default) or intel
+ syntax.
+
+
+
+
+
+EXIT STATUS
+-----------
+
+
+If **llc** succeeds, it will exit with 0.  Otherwise, if an error occurs,
+it will exit with a non-zero value.
+
+
+SEE ALSO
+--------
+
+
+lli|lli