RFA: testsuite patches (4/6): vrp55.c can only thread when not keeping null pointer checks.

[Joern Rennecke]

Tested for avr with --target_board=atmega128-sim and native on  
i686-pc-linuc-gnu.

Ok to apply?
2013-08-17  Joern Rennecke  <joern.renne...@embecosm.com>
        * gcc.dg/tree-ssa/vrp55.c: Use keeps_null_pointer_checks to determine
        correct test response.

Index: gcc.dg/tree-ssa/vrp55.c
===================================================================
--- gcc.dg/tree-ssa/vrp55.c     (revision 201835)
+++ gcc.dg/tree-ssa/vrp55.c     (working copy)
@@ -9,6 +9,7 @@ fu (char *p, int x)
     arf ();
 }
 
-/* { dg-final { scan-tree-dump-times "Threaded jump" 1 "vrp1" } } */
+/* { dg-final { scan-tree-dump-times "Threaded jump" 1 "vrp1" { target { ! 
keeps_null_pointer_checks } } } } */
+/* { dg-final { scan-tree-dump-times "Threaded jump" 0 "vrp1" { target {   
keeps_null_pointer_checks } } } } */
 /* { dg-final { cleanup-tree-dump "vrp1" } } */