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re PR tree-optimization/70701 (incomplete value numbering when memcpy-ing from array) 

2016-04-18  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/70701
	* tree-ssa-sccvn.c (vn_reference_lookup_3): Resolve fully constant
	references after translating through a memcpy.

	* gcc.dg/tree-ssa/ssa-fre-53.c: New testcase.

From-SVN: r235131
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Richard Biener 2016-04-18 11:39:04 +00:00 committed by Richard Biener
parent 65833da69d
commit edd048e29a
4 changed files with 28 additions and 0 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2016-04-18 Richard Biener <rguenther@suse.de>
PR tree-optimization/70701
* tree-ssa-sccvn.c (vn_reference_lookup_3): Resolve fully constant
references after translating through a memcpy.
2016-04-18 Richard Biener <rguenther@suse.de>
* tree-ssa-pre.c (postorder, postorder_num): Make locals ...

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2016-04-18 Richard Biener <rguenther@suse.de>
PR tree-optimization/70701
* gcc.dg/tree-ssa/ssa-fre-53.c: New testcase.
2016-04-18 Tom de Vries <tom@codesourcery.com>
PR testsuite/70699

11
gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-53.c Normal file
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@ -0,0 +1,11 @@
/* { dg-do compile } */
/* { dg-options "-O -fno-tree-forwprop -fdump-tree-fre1" } */
const int a[]={1,2,3};
int f(){
int*b=__builtin_malloc(12);
__builtin_memcpy(b,a,12);
return b[0];
}
/* { dg-final { scan-tree-dump "return 1;" "fre1" } } */

6
gcc/tree-ssa-sccvn.c
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@ -2152,6 +2152,12 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_,
vr->operands[1] = op;
vr->hashcode = vn_reference_compute_hash (vr);
/* Try folding the new reference to a constant. */
tree val = fully_constant_vn_reference_p (vr);
if (val)
return vn_reference_lookup_or_insert_for_pieces
(vuse, vr->set, vr->type, vr->operands, val);
/* Adjust *ref from the new operands. */
if (!ao_ref_init_from_vn_reference (&r, vr->set, vr->type, vr->operands))
return (void *)-1;