alias.c (rtx_refs_may_alias_p): Do not resort to TBAA if either alias-set is zero.

2010-08-04  Richard Guenther  <rguenther@suse.de>

	* alias.c (rtx_refs_may_alias_p): Do not resort to TBAA
	if either alias-set is zero.

From-SVN: r162867

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 77424eba5f83cf77fbaa845e7a89efc991723d96..23f0d8861de0f5477a43d4cc1253b4a8bfd72943 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2010-08-04  Richard Guenther  <rguenther@suse.de>
+
+       * alias.c (rtx_refs_may_alias_p): Do not resort to TBAA
+       if either alias-set is zero.
+
 2010-08-04  Richard Guenther  <rguenther@suse.de>
 
        * tree-ssa-propagate.h (struct prop_value_d, prop_value_t): Move ...

diff --git a/gcc/alias.c b/gcc/alias.c
index 9b70bb86bb26cfe4a4ddb0c3595b6c77e747eccc..f5de4db9d753f19d72aa85b1cbb3fa4f84846243 100644 (file)
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -354,7 +354,10 @@ rtx_refs_may_alias_p (const_rtx x, const_rtx mem, bool tbaa_p)
       || !ao_ref_from_mem (&ref2, mem))
     return true;
 
-  return refs_may_alias_p_1 (&ref1, &ref2, tbaa_p);
+  return refs_may_alias_p_1 (&ref1, &ref2,
+                            tbaa_p
+                            && MEM_ALIAS_SET (x) != 0
+                            && MEM_ALIAS_SET (mem) != 0);
 }
 
 /* Returns a pointer to the alias set entry for ALIAS_SET, if there is