re PR tree-optimization/68951 (ICE in vect_update_misalignment_for_peel)

2015-12-17  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/68951
	* tree-vect-data-refs.c (vect_peeling_hash_get_lowest_cost):
	Ignore strided non-group accesses.

	* gcc.dg/torture/pr68951.c: New testcase.

From-SVN: r231754

gcc/ChangeLog

+2015-12-17  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/68951
+	* tree-vect-data-refs.c (vect_peeling_hash_get_lowest_cost):
+	Ignore strided non-group accesses.
+
 2015-12-17  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* config/arc/arc.c (arc_loop_hazard): Don't convert the jump label

gcc/testsuite/ChangeLog

+2015-12-17  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/68951
+	* gcc.dg/torture/pr68951.c: New testcase.
+
 2015-12-17  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
 	PR target/67973

gcc/testsuite/gcc.dg/torture/pr68951.c

+/* { dg-do compile } */
+/* { dg-additional-options "-w" } */
+
+static int g_534[1][1];
+int fn1()
+{
+  int i;
+  for (i = 0; i < 4; i++)
+    g_534[i + 2][i] ^= 3;
+  for (;;)
+    ;
+}

gcc/tree-vect-data-refs.c

@@ -1215,6 +1215,12 @@ vect_peeling_hash_get_lowest_cost (_vect_peel_info **slot,
           && GROUP_FIRST_ELEMENT (stmt_info) != stmt)
         continue;
 
+      /* Strided accesses perform only component accesses, alignment is
+         irrelevant for them.  */
+      if (STMT_VINFO_STRIDED_P (stmt_info)
+	  && !STMT_VINFO_GROUPED_ACCESS (stmt_info))
+	continue;
+
       save_misalignment = DR_MISALIGNMENT (dr);
       vect_update_misalignment_for_peel (dr, elem->dr, elem->npeel);
       vect_get_data_access_cost (dr, &inside_cost, &outside_cost,