tree-vrp.c (update_value_range): Intersect the range with old recorded SSA name range information.

2015-01-27  Richard Biener  <rguenther@suse.de>

	* tree-vrp.c (update_value_range): Intersect the range with
	old recorded SSA name range information.

From-SVN: r220164

gcc/ChangeLog

+2015-01-27  Richard Biener  <rguenther@suse.de>
+
+	* tree-vrp.c (update_value_range): Intersect the range with
+	old recorded SSA name range information.
+
 2015-01-27  Nick Clifton  <nickc@redhat.com>
 
 	* config/rl78/rl78.c (rl78_expand_prologue): In G10 mode push the

gcc/tree-vrp.c

@@ -847,6 +847,23 @@ update_value_range (const_tree var, value_range_t *new_vr)
   value_range_t *old_vr;
   bool is_new;
 
+  /* If there is a value-range on the SSA name from earlier analysis
+     factor that in.  */
+  if (INTEGRAL_TYPE_P (TREE_TYPE (var)))
+    {
+      wide_int min, max;
+      value_range_type rtype = get_range_info (var, &min, &max);
+      if (rtype == VR_RANGE || rtype == VR_ANTI_RANGE)
+	{
+	  value_range_d nr;
+	  nr.type = rtype;
+	  nr.min = wide_int_to_tree (TREE_TYPE (var), min);
+	  nr.max = wide_int_to_tree (TREE_TYPE (var), max);
+	  nr.equiv = NULL;
+	  vrp_intersect_ranges (new_vr, &nr);
+	}
+    }
+
   /* Update the value range, if necessary.  */
   old_vr = get_value_range (var);
   is_new = old_vr->type != new_vr->type