re PR tree-optimization/50955 (IVopts incorrectly rewrite the address of a…

re PR tree-optimization/50955 (IVopts incorrectly rewrite the address of a global memory access into a local form.)

2012-02-06  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/50955
	* tree-ssa-loop-ivopts.c (get_computation_cost_at): Artificially
	raise cost of expressions that replace an address with an
	expression based on a different pointer.

From-SVN: r183934

gcc/ChangeLog

+2012-02-06  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/50955
+	* tree-ssa-loop-ivopts.c (get_computation_cost_at): Artificially
+	raise cost of expressions that replace an address with an
+	expression based on a different pointer.
+
 2012-02-06  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/52129

gcc/tree-ssa-loop-ivopts.c

@@ -4048,7 +4048,11 @@ get_computation_cost_at (struct ivopts_data *data,
       return infinite_cost;
     }
 
-  if (address_p)
+  if (address_p
+      || (use->iv->base_object
+	  && cand->iv->base_object
+	  && POINTER_TYPE_P (TREE_TYPE (use->iv->base_object))
+	  && POINTER_TYPE_P (TREE_TYPE (cand->iv->base_object))))
     {
       /* Do not try to express address of an object with computation based
 	 on address of a different object.  This may cause problems in rtl