re PR middle-end/60482 (Loop optimization regression)

	PR middle-end/60482
	* tree-vrp.c (register_edge_assert_for_1): Don't add assert
	if there are multiple uses, but op doesn't live on E edge.
	* tree-cfg.c (assert_unreachable_fallthru_edge_p): Also ignore
	clobber stmts before __builtin_unreachable.

	* gcc.dg/vect/pr60482.c: New test.

From-SVN: r208506

gcc/ChangeLog

+2014-03-12  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/60482
+	* tree-vrp.c (register_edge_assert_for_1): Don't add assert
+	if there are multiple uses, but op doesn't live on E edge.
+	* tree-cfg.c (assert_unreachable_fallthru_edge_p): Also ignore
+	clobber stmts before __builtin_unreachable.
+
 2014-03-11  Richard Sandiford  <rdsandiford@googlemail.com>
 
 	* builtins.c (expand_builtin_setjmp_receiver): Use and clobber

gcc/testsuite/ChangeLog

+2014-03-12  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/60482
+	* gcc.dg/vect/pr60482.c: New test.
+
 2014-03-11  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/60389

gcc/testsuite/gcc.dg/vect/pr60482.c

+/* PR middle-end/60482 */
+/* { dg-do compile } */
+/* { dg-additional-options "-Ofast" } */
+/* { dg-require-effective-target vect_int } */
+
+double
+foo (double *x, int n)
+{
+  double p = 0.0;
+  int i;
+  x = __builtin_assume_aligned (x, 128);
+  if (n % 128)
+    __builtin_unreachable ();
+  for (i = 0; i < n; i++)
+    p += x[i];
+  return p;
+}
+
+/* { dg-final { scan-tree-dump-not "epilog loop required" "vect" } } */
+/* { dg-final { cleanup-tree-dump "vect" } } */

gcc/tree-cfg.c

@@ -410,9 +410,9 @@ assert_unreachable_fallthru_edge_p (edge e)
 	  if (gsi_end_p (gsi))
 	    return false;
 	  stmt = gsi_stmt (gsi);
-	  if (is_gimple_debug (stmt))
+	  while (is_gimple_debug (stmt) || gimple_clobber_p (stmt))
 	    {
-	      gsi_next_nondebug (&gsi);
+	      gsi_next (&gsi);
 	      if (gsi_end_p (gsi))
 		return false;
 	      stmt = gsi_stmt (gsi);

gcc/tree-vrp.c

@@ -5423,12 +5423,9 @@ register_edge_assert_for_1 (tree op, enum tree_code code,
     return false;
 
   /* We know that OP will have a zero or nonzero value.  If OP is used
-     more than once go ahead and register an assert for OP.
-
-     The FOUND_IN_SUBGRAPH support is not helpful in this situation as
-     it will always be set for OP (because OP is used in a COND_EXPR in
-     the subgraph).  */
-  if (!has_single_use (op))
+     more than once go ahead and register an assert for OP.  */
+  if (live_on_edge (e, op)
+      && !has_single_use (op))
     {
       val = build_int_cst (TREE_TYPE (op), 0);
       register_new_assert_for (op, op, code, val, NULL, e, bsi);