[GOOGLE] Fix an ICE in lipo_cmp_type

[Dehao Chen]

This fixes an ICE when lipo_cmp_type handles NULL_PTR_TYPE.

Bootstrapped and regression test on going?

OK for google branches?

Thanks,
Dehao

Index: gcc/l-ipo.c
===================================================================
--- gcc/l-ipo.c (revision 202926)
+++ gcc/l-ipo.c (working copy)
@@ -713,6 +713,7 @@ lipo_cmp_type (tree t1, tree t2)
               && lipo_cmp_type (TREE_TYPE (t1), TREE_TYPE (t2)));
     case VOID_TYPE:
     case BOOLEAN_TYPE:
+    case NULLPTR_TYPE:
       return 1;
     case TEMPLATE_TYPE_PARM:
       return 1;