tree-vect-data-refs.c (vect_slp_analyze_node_dependences): Handle memory…

tree-vect-data-refs.c (vect_slp_analyze_node_dependences): Handle memory using/clobbering stmts without a STMT_VINFO_DATA_REF conservatively.

2015-11-10  Richard Biener  <rguenther@suse.de>

	* tree-vect-data-refs.c (vect_slp_analyze_node_dependences):
	Handle memory using/clobbering stmts without a STMT_VINFO_DATA_REF
	conservatively.

From-SVN: r230094

gcc/ChangeLog

 2015-11-10  Richard Biener  <rguenther@suse.de>
 
+	* tree-vect-data-refs.c (vect_slp_analyze_node_dependences):
+	Handle memory using/clobbering stmts without a STMT_VINFO_DATA_REF
+	conservatively.
+
+2015-11-10  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/56118
 	* tree-vect-slp.c (vect_bb_vectorization_profitable_p): Make equal
 	cost favor vectorized version.

gcc/tree-vect-data-refs.c

@@ -573,21 +573,22 @@ vect_slp_analyze_node_dependences (slp_instance instance, slp_tree node)
       gimple *access = SLP_TREE_SCALAR_STMTS (node)[k];
       if (access == last_access)
 	continue;
-      stmt_vec_info access_stmt_info = vinfo_for_stmt (access);
-      gimple_stmt_iterator gsi = gsi_for_stmt (access);
-      gsi_next (&gsi);
-      for (; gsi_stmt (gsi) != last_access; gsi_next (&gsi))
+      data_reference *dr_a = STMT_VINFO_DATA_REF (vinfo_for_stmt (access));
+      for (gimple_stmt_iterator gsi = gsi_for_stmt (access);
+	   gsi_stmt (gsi) != last_access; gsi_next (&gsi))
 	{
 	  gimple *stmt = gsi_stmt (gsi);
-	  stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
-	  if (!STMT_VINFO_DATA_REF (stmt_info)
-	      || (DR_IS_READ (STMT_VINFO_DATA_REF (stmt_info))
-		  && DR_IS_READ (STMT_VINFO_DATA_REF (access_stmt_info))))
+	  if (! gimple_vuse (stmt)
+	      || (DR_IS_READ (dr_a) && ! gimple_vdef (stmt)))
 	    continue;
 
-	  ddr_p ddr = initialize_data_dependence_relation
-	      (STMT_VINFO_DATA_REF (access_stmt_info),
-	       STMT_VINFO_DATA_REF (stmt_info), vNULL);
+	  /* If we couldn't record a (single) data reference for this
+	     stmt we have to give up.  */
+	  data_reference *dr_b = STMT_VINFO_DATA_REF (vinfo_for_stmt (stmt));
+	  if (!dr_b)
+	    return false;
+
+	  ddr_p ddr = initialize_data_dependence_relation (dr_a, dr_b, vNULL);
 	  if (vect_slp_analyze_data_ref_dependence (ddr))
 	    {
 	      /* ???  If the dependence analysis failed we can resort to the