re PR middle-end/65962 (Missed vectorization of strided stores)

2015-10-28  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/65962
	* tree-ssa-pre.c (eliminate_dom_walker::before_dom_children):
	Avoid creating loop carried dependences also for outer loops
	of the loop a use to replace is in.

	* gcc.dg/vect/vect-62.c: Adjust.

From-SVN: r229481

gcc/ChangeLog

 2015-10-28  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/65962
+	* tree-ssa-pre.c (eliminate_dom_walker::before_dom_children):
+	Avoid creating loop carried dependences also for outer loops
+	of the loop a use to replace is in.
+
+2015-10-28  Richard Biener  <rguenther@suse.de>
+
 	* common.opt (fchecking): New flag controlling flag_checking.
 	* passes.c (verify_curr_properties): Drop DEBUG_FUNCTION.
 	* timevar.c (timer::print): Adjust output.

gcc/testsuite/ChangeLog

 2015-10-28  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/65962
+	* gcc.dg/vect/vect-62.c: Adjust.
+
+2015-10-28  Richard Biener  <rguenther@suse.de>
+
 	PR middle-end/68067
 	* gcc.dg/torture/pr68067-1.c: New testcase.
 	* gcc.dg/torture/pr68067-2.c: Likewise.

gcc/testsuite/gcc.dg/vect/vect-62.c

@@ -33,9 +33,8 @@ int main1 ()
     }
 
   /* Multidimensional array. Aligned. The "inner" dimensions
-     are invariant in the inner loop. Vectorizable, but the
-     vectorizer detects that everything is invariant and that
-     the loop is better left untouched. (it should be optimized away). */
+     are invariant in the inner loop.  The outer loop is
+     vectorizable after invariant/store motion.  */
   for (i = 0; i < N; i++)
     {
       for (j = 0; j < N; j++)
@@ -65,5 +64,5 @@ int main (void)
   return main1 ();
 }
 
-/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
+/* { dg-final { scan-tree-dump-times "vectorized 2 loops" 1 "vect" } } */
 /* { dg-final { scan-tree-dump-times "Vectorizing an unaligned access" 0 "vect" } } */

gcc/tree-ssa-pre.c

@@ -4082,8 +4082,9 @@ eliminate_dom_walker::before_dom_children (basic_block b)
 	      gimple *def_stmt = SSA_NAME_DEF_STMT (sprime);
 	      basic_block def_bb = gimple_bb (def_stmt);
 	      if (gimple_code (def_stmt) == GIMPLE_PHI
-		  && b->loop_father->header == def_bb)
+		  && def_bb->loop_father->header == def_bb)
 		{
+		  loop_p loop = def_bb->loop_father;
 		  ssa_op_iter iter;
 		  tree op;
 		  bool found = false;
@@ -4092,9 +4093,8 @@ eliminate_dom_walker::before_dom_children (basic_block b)
 		      affine_iv iv;
 		      def_bb = gimple_bb (SSA_NAME_DEF_STMT (op));
 		      if (def_bb
-			  && flow_bb_inside_loop_p (b->loop_father, def_bb)
-			  && simple_iv (b->loop_father,
-					b->loop_father, op, &iv, true))
+			  && flow_bb_inside_loop_p (loop, def_bb)
+			  && simple_iv (loop, loop, op, &iv, true))
 			{
 			  found = true;
 			  break;
@@ -4110,7 +4110,7 @@ eliminate_dom_walker::before_dom_children (basic_block b)
 			  print_generic_expr (dump_file, sprime, 0);
 			  fprintf (dump_file, " which would add a loop"
 				   " carried dependence to loop %d\n",
-				   b->loop_father->num);
+				   loop->num);
 			}
 		      /* Don't keep sprime available.  */
 		      sprime = NULL_TREE;