1 files changed, 25 insertions, 22 deletions
diff --git a/contrib/gcc/doc/c-tree.texi b/contrib/gcc/doc/c-tree.texi
index 35da90a..8f5a5bb 100644
--- a/contrib/gcc/doc/c-tree.texi
+++ b/contrib/gcc/doc/c-tree.texi
@@ -84,8 +84,8 @@ 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
+@code{TREE_CODE} macro.  Many, many macros take trees as input and
+return trees as output.  However, most macros require a certain kind 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.
 
@@ -1771,6 +1771,7 @@ This macro returns the attributes on the type @var{type}.
 @tindex CLEANUP_POINT_EXPR
 @tindex ARRAY_REF
 @tindex VTABLE_REF
+@tindex VA_ARG_EXPR
 
 The internal representation for expressions is for the most part quite
 straightforward.  However, there are a few facts that one must bear in
@@ -2062,7 +2063,7 @@ 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
+always @code{a - (a/b)*b} where the division is as if computed by a
 @code{TRUNC_DIV_EXPR}.
 
 @item ARRAY_REF
@@ -2126,25 +2127,21 @@ 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.
+the value of the expression.
+
+The second operand must have the same type as the entire expression,
+unless it unconditionally throws an exception or calls a noreturn
+function, in which case it should have void type.  The same constraints
+apply to the third operand.  This allows array bounds checks to be
+represented conveniently as @code{(i >= 0 && i < 10) ? i : abort()}.
+
+As a GNU extension, the C language front-ends allow the second
+operand of the @code{?:} operator may be omitted in the source.
+For example, @code{x ? : 3} is equivalent to @code{x ? x : 3},
+assuming that @code{x} is an expression without side-effects.
+In the tree representation, however, the second operand is always
+present, possibly protected by @code{SAVE_EXPR} if the first
+argument does cause side-effects.
 
 @item CALL_EXPR
 These nodes are used to represent calls to functions, including
@@ -2312,4 +2309,10 @@ 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.
 
+@item VA_ARG_EXPR
+This node is used to implement support for the C/C++ variable argument-list
+mechanism.  It represents expressions like @code{va_arg (ap, type)}.
+Its @code{TREE_TYPE} yields the tree representation for @code{type} and
+its sole argument yields the representation for @code{ap}.
+
 @end table