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* doc/c-tree.texi: Update description of COND_EXPR tree nodes.

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Roger Sayle 2002-10-18 03:29:17 +00:00 committed by Roger Sayle
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@ -1,3 +1,7 @@
2002-10-17 Roger Sayle <roger@eyesopen.com>
* doc/c-tree.texi: Update description of COND_EXPR tree nodes.
2002-10-17 Geoffrey Keating <geoffk@apple.com>
* config/rs6000/rs6000.h (HARD_REGNO_MODE_OK): Allow arbitrary modes

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gcc/doc/c-tree.texi
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@ -2127,25 +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:
the value of the expression.
@example
x ? : 3
@end example
@noindent
which is equivalent to
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()}.
@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.
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