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re PR middle-end/21595 (__builtin_constant_p(&"Hello"[0]) is true for C but not for C++)

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2005-05-17  Richard Guenther  <rguenth@gcc.gnu.org>

	PR middle-end/21595
	* builtins.c (fold_builtin_constant_p): Handle
	&"string cst"[0] as constant.

	* g++.dg/tree-ssa/builtin1.C: New testcase.

From-SVN: r99825
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Richard Guenther 2005-05-17 09:00:03 +00:00 • committed by Richard Biener
parent 64e6863ed5
commit fb664a2cba
4 changed files with 31 additions and 3 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2005-05-17 Richard Guenther <rguenth@gcc.gnu.org>
PR middle-end/21595
* builtins.c (fold_builtin_constant_p): Handle
&"string cst"[0] as constant.
2005-05-17 Richard Henderson <rth@redhat.com>
* config/i386/sse.md (mulv16qi3, mulv2di3): New.

13
gcc/builtins.c
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@ -6338,10 +6338,17 @@ fold_builtin_constant_p (tree arglist)
/* If we know this is a constant, emit the constant of one. */
if (CONSTANT_CLASS_P (arglist)
|| (TREE_CODE (arglist) == CONSTRUCTOR
&& TREE_CONSTANT (arglist))
|| (TREE_CODE (arglist) == ADDR_EXPR
&& TREE_CODE (TREE_OPERAND (arglist, 0)) == STRING_CST))
&& TREE_CONSTANT (arglist)))
return integer_one_node;
if (TREE_CODE (arglist) == ADDR_EXPR)
{
tree op = TREE_OPERAND (arglist, 0);
if (TREE_CODE (op) == STRING_CST
|| (TREE_CODE (op) == ARRAY_REF
&& integer_zerop (TREE_OPERAND (op, 1))
&& TREE_CODE (TREE_OPERAND (op, 0)) == STRING_CST))
return integer_one_node;
}
/* If this expression has side effects, show we don't know it to be a
constant. Likewise if it's a pointer or aggregate type since in

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2005-05-17 Richard Guenther <rguenth@gcc.gnu.org>
PR middle-end/21595
* g++.dg/tree-ssa/builtin1.C: New testcase.
2005-05-17 Jakub Jelinek <jakub@redhat.com>
PR c++/21454

10
gcc/testsuite/g++.dg/tree-ssa/builtin1.C Normal file
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@ -0,0 +1,10 @@
// { dg-do link }
extern void link_error();
int main()
{
if (! __builtin_constant_p (&"Hello"[0]))
link_error();
return 0;
}