re PR c/48885 (missed optimization with restrict qualifier?)

2015-09-24  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/48885
	* tree-ssa-structalias.c (visit_loadstore): Handle default defs
	as not including any restrict tags from other pointers.

	* gcc.dg/tree-ssa/restrict-6.c: New testcase.

From-SVN: r228073

gcc/ChangeLog

+2015-09-24  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/48885
+	* tree-ssa-structalias.c (visit_loadstore): Handle default defs
+	as not including any restrict tags from other pointers.
+
 2015-09-23  Thomas Schwinge  <thomas@codesourcery.com>
 
 	* gcc.c (handle_foffload_option): Don't lose the trailing NUL

gcc/testsuite/ChangeLog

+2015-09-24  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/48885
+	* gcc.dg/tree-ssa/restrict-6.c: New testcase.
+
 2015-09-24  Patrick Palka  <ppalka@gcc.gnu.org>
 
 	* c-c++-common/Wmisleading-indentation.c: Augment test.

gcc/testsuite/gcc.dg/tree-ssa/restrict-6.c

+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-fre1" } */
+
+void
+test (int *a, int *b, int * __restrict__ v)
+{
+  *a = *v;
+  *b = *v;
+}
+
+/* { dg-final { scan-tree-dump-times "= \\*v" 1 "fre1" } } */

gcc/tree-ssa-structalias.c

@@ -6952,10 +6952,11 @@ visit_loadstore (gimple *, tree base, tree ref, void *clique_)
       || TREE_CODE (base) == TARGET_MEM_REF)
     {
       tree ptr = TREE_OPERAND (base, 0);
-      if (TREE_CODE (ptr) == SSA_NAME)
+      if (TREE_CODE (ptr) == SSA_NAME
+	  && ! SSA_NAME_IS_DEFAULT_DEF (ptr))
 	{
 	  /* ???  We need to make sure 'ptr' doesn't include any of
-	     the restrict tags in its points-to set.  */
+	     the restrict tags we added bases for in its points-to set.  */
 	  return false;
 	}