re PR tree-optimization/32921 (Revision 126326 causes 12% slowdown)

2008-04-30  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/32921
	* tree-ssa-loop-im.c (mem_refs_may_alias_p): Disambiguate with TBAA.

From-SVN: r134838

gcc/ChangeLog

+2008-04-30  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/32921
+	* tree-ssa-loop-im.c (mem_refs_may_alias_p): Disambiguate with TBAA.
+
 2008-04-30  Richard Sandiford  <rsandifo@nildram.co.uk>
 
 	* config/arm/arm.c (arm_unwind_emit): Use

gcc/tree-ssa-loop-im.c

@@ -1640,6 +1640,8 @@ mem_refs_may_alias_p (tree mem1, tree mem2, struct pointer_map_t **ttae_cache)
 	  && SSA_VAR_P (mem1)
 	  && !AGGREGATE_TYPE_P (TREE_TYPE (mem1)))
 	return false;
+      if (!alias_sets_conflict_p (get_alias_set (mem1), get_alias_set (mem2)))
+	return false;
     }
 
   /* The expansion of addresses may be a bit expensive, thus we only do