[PATCH][TUPLES] Fix for gcc.dg/conv-2.c failures.

[Doug Kwan (關振德)]

Hi Aldy,

    Could you review this?  For some reason, this is different from
the trunk and it causes 30+ failing tests.

-Doug

2008-04-14  Doug Kwan  <dougkwan@google.com>

        * c-typeck.c (convert_for_assignment): Call c_common_unsigned_type

Index: gcc/gcc/c-typeck.c
===================================================================
--- gcc/gcc/c-typeck.c  (revision 134253)
+++ gcc/gcc/c-typeck.c  (working copy)
@@ -4253,8 +4253,8 @@ convert_for_assignment (tree type, tree
       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
          || (target_cmp = comp_target_types (type, rhstype))
          || is_opaque_pointer
-         || (unsigned_type_for (mvl)
-             == unsigned_type_for (mvr)))
+         || (c_common_unsigned_type (mvl)
+             == c_common_unsigned_type (mvr)))
        {
          if (pedantic
              && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)