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tree-ssa-alias.c (refs_may_alias_p_1): Do not use TBAA for decl-vs-decl disambiguation.

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2009-04-17  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-alias.c (refs_may_alias_p_1): Do not use TBAA
	for decl-vs-decl disambiguation.

From-SVN: r146273
This commit is contained in:
Richard Guenther 2009-04-17 15:35:13 +00:00 • committed by Richard Biener
parent 90c6fd8a8b
commit 61e20b90d9
2 changed files with 26 additions and 13 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2009-04-17 Richard Guenther <rguenther@suse.de>
* tree-ssa-alias.c (refs_may_alias_p_1): Do not use TBAA
for decl-vs-decl disambiguation.
2009-04-17 Andreas Krebbel <krebbel1@de.ibm.com>
* config/s390/s390.h (s390_tune_attr): New macro definition.

34
gcc/tree-ssa-alias.c
View file

@ -670,16 +670,6 @@ refs_may_alias_p_1 (tree ref1, tree ref2)
|| INDIRECT_REF_P (ref2)
|| TREE_CODE (ref2) == TARGET_MEM_REF));
/* Defer to TBAA if possible. */
if (flag_strict_aliasing
&& !alias_sets_conflict_p (get_alias_set (ref1), get_alias_set (ref2)))
return false;
/* If one reference is a TARGET_MEM_REF weird things are allowed. */
if (TREE_CODE (ref1) == TARGET_MEM_REF
|| TREE_CODE (ref2) == TARGET_MEM_REF)
return true;
/* Decompose the references into their base objects and the access. */
base1 = get_ref_base_and_extent (ref1, &offset1, &size1, &max_size1);
base2 = get_ref_base_and_extent (ref2, &offset2, &size2, &max_size2);
@ -693,14 +683,32 @@ refs_may_alias_p_1 (tree ref1, tree ref2)
|| is_gimple_min_invariant (base2))
return false;
/* Defer to simple offset based disambiguation if we have
references based on two decls. Do this before defering to
TBAA to handle must-alias cases in conformance with the
GCC extension of allowing type-punning through unions. */
var1_p = SSA_VAR_P (base1);
var2_p = SSA_VAR_P (base2);
ind1_p = INDIRECT_REF_P (base1);
ind2_p = INDIRECT_REF_P (base2);
if (var1_p && var2_p)
return decl_refs_may_alias_p (base1, offset1, max_size1,
base2, offset2, max_size2);
else if (var1_p && ind2_p)
/* First defer to TBAA if possible. */
if (flag_strict_aliasing
&& !alias_sets_conflict_p (get_alias_set (ref1), get_alias_set (ref2)))
return false;
/* If one reference is a TARGET_MEM_REF weird things are allowed. Still
TBAA disambiguation based on the access type is possible, so bail
out only after that check. */
if (TREE_CODE (ref1) == TARGET_MEM_REF
|| TREE_CODE (ref2) == TARGET_MEM_REF)
return true;
/* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
ind1_p = INDIRECT_REF_P (base1);
ind2_p = INDIRECT_REF_P (base2);
if (var1_p && ind2_p)
return indirect_ref_may_alias_decl_p (ref2, TREE_OPERAND (base2, 0),
offset2, max_size2, -1,
ref1, base1,