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alias.c (alias_set_subset_of): Correctly handle asking if zero is a subset of an alias set with zero child.

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2008-04-23  Richard Guenther  <rguenther@suse.de>

	* alias.c (alias_set_subset_of): Correctly handle asking
	if zero is a subset of an alias set with zero child.
	* tree-ssa-alias.c (have_common_aliases_p): Simplify logic.
	(compute_flow_insensitive_aliasing): Correctly walk all
	pointers.  Do not unnecessarily union sets.

From-SVN: r134597
This commit is contained in:
Richard Guenther 2008-04-23 14:06:02 +00:00 committed by Richard Biener
parent f3f75f693d
commit a7a512beff
3 changed files with 18 additions and 17 deletions
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8
gcc/ChangeLog
View File

@ -1,3 +1,11 @@
2008-04-23 Richard Guenther <rguenther@suse.de>
* alias.c (alias_set_subset_of): Correctly handle asking
if zero is a subset of an alias set with zero child.
* tree-ssa-alias.c (have_common_aliases_p): Simplify logic.
(compute_flow_insensitive_aliasing): Correctly walk all
pointers. Do not unnecessarily union sets.
2008-04-23 Richard Guenther <rguenther@suse.de>
PR middle-end/36021

5
gcc/alias.c
View File

@ -305,8 +305,9 @@ alias_set_subset_of (alias_set_type set1, alias_set_type set2)
/* Otherwise, check if set1 is a subset of set2. */
ase = get_alias_set_entry (set2);
if (ase != 0
&& (splay_tree_lookup (ase->children,
(splay_tree_key) set1)))
&& ((ase->has_zero_child && set1 == 0)
|| splay_tree_lookup (ase->children,
(splay_tree_key) set1)))
return true;
return false;
}

22
gcc/tree-ssa-alias.c
View File

@ -2390,9 +2390,7 @@ have_common_aliases_p (bitmap tag1aliases, bitmap tag2aliases)
/* This is the old behavior of have_common_aliases_p, which is to
return false if both sets are empty, or one set is and the other
isn't. */
if ((tag1aliases == NULL && tag2aliases != NULL)
|| (tag2aliases == NULL && tag1aliases != NULL)
|| (tag1aliases == NULL && tag2aliases == NULL))
if (tag1aliases == NULL || tag2aliases == NULL)
return false;
return bitmap_intersect_p (tag1aliases, tag2aliases);
@ -2490,12 +2488,16 @@ compute_flow_insensitive_aliasing (struct alias_info *ai)
if (PTR_IS_REF_ALL (p_map1->var))
continue;
for (j = i + 1; j < ai->num_pointers; j++)
for (j = 0; j < ai->num_pointers; j++)
{
struct alias_map_d *p_map2 = ai->pointers[j];
tree tag2 = symbol_mem_tag (p_map2->var);
bitmap may_aliases2 = may_aliases (tag2);
/* By convention tags don't alias themselves. */
if (tag1 == tag2)
continue;
if (PTR_IS_REF_ALL (p_map2->var))
continue;
@ -2508,18 +2510,8 @@ compute_flow_insensitive_aliasing (struct alias_info *ai)
if (have_common_aliases_p (may_aliases1, may_aliases2))
continue;
if (may_aliases2 && !bitmap_empty_p (may_aliases2))
{
union_alias_set_into (tag1, may_aliases2);
}
else
{
/* Since TAG2 does not have any aliases of its own, add
TAG2 itself to the alias set of TAG1. */
add_may_alias (tag1, tag2);
}
add_may_alias (tag1, tag2);
}
}
timevar_pop (TV_FLOW_INSENSITIVE);
}