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re PR middle-end/58564 (possible wrong code bug at -O0) 

PR middle-end/58564
	* fold-const.c (fold_ternary_loc): For A < 0 : <sign bit of A> : 0
	optimization, punt if sign_bit_p looked through any zero extension.

	* gcc.c-torture/execute/pr58564.c: New test.

From-SVN: r203042
This commit is contained in:
Jakub Jelinek 2013-09-30 22:15:20 +02:00 committed by Jakub Jelinek
parent 05357ac367
commit f66d089128
4 changed files with 42 additions and 3 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2013-09-30 Jakub Jelinek <jakub@redhat.com>
PR middle-end/58564
* fold-const.c (fold_ternary_loc): For A < 0 : <sign bit of A> : 0
optimization, punt if sign_bit_p looked through any zero extension.
2013-09-30 Teresa Johnson <tejohnson@google.com>
* tree-ssa-threadupdate.c (ssa_fix_duplicate_block_edges):

17
gcc/fold-const.c
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@ -14196,13 +14196,28 @@ fold_ternary_loc (location_t loc, enum tree_code code, tree type,
&& integer_zerop (op2)
&& (tem = sign_bit_p (TREE_OPERAND (arg0, 0), arg1)))
{
/* sign_bit_p looks through both zero and sign extensions,
but for this optimization only sign extensions are
usable. */
tree tem2 = TREE_OPERAND (arg0, 0);
while (tem != tem2)
{
if (TREE_CODE (tem2) != NOP_EXPR
|| TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (tem2, 0))))
{
tem = NULL_TREE;
break;
}
tem2 = TREE_OPERAND (tem2, 0);
}
/* sign_bit_p only checks ARG1 bits within A's precision.
If <sign bit of A> has wider type than A, bits outside
of A's precision in <sign bit of A> need to be checked.
If they are all 0, this optimization needs to be done
in unsigned A's type, if they are all 1 in signed A's type,
otherwise this can't be done. */
if (TYPE_PRECISION (TREE_TYPE (tem))
if (tem
&& TYPE_PRECISION (TREE_TYPE (tem))
< TYPE_PRECISION (TREE_TYPE (arg1))
&& TYPE_PRECISION (TREE_TYPE (tem))
< TYPE_PRECISION (type))

6
gcc/testsuite/ChangeLog
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@ -1,9 +1,13 @@
2013-09-30 Jakub Jelinek <jakub@redhat.com>
PR middle-end/58564
* gcc.c-torture/execute/pr58564.c: New test.
2013-09-30 Teresa Johnson <tejohnson@google.com>
* testsuite/gcc.dg/tree-ssa/ssa-dom-thread-3.c (expand_one_var):
Update for additional dump message.
2013-09-30 Richard Biener <rguenther@suse.de>
PR tree-optimization/58554

14
gcc/testsuite/gcc.c-torture/execute/pr58564.c Normal file
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@ -0,0 +1,14 @@
/* PR middle-end/58564 */
extern void abort (void);
int a, b;
short *c, **d = &c;
int
main ()
{
b = (0, 0 > ((&c == d) & (1 && (a ^ 1)))) | 0U;
if (b != 0)
abort ();
return 0;
}