re PR c/39464 (Attribute may_alias causes invalid warning)

	PR c/39464
	* c-typeck.c (convert_for_assignment): For -Wpointer-sign
	warning require that both c_common_unsigned_type as well as
	c_common_signed_type is the same for both mvl and mvr types.

	* gcc.dg/pr39464.c: New test.

From-SVN: r194594

gcc/c/ChangeLog

+2012-12-18  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/39464
+	* c-typeck.c (convert_for_assignment): For -Wpointer-sign
+	warning require that both c_common_unsigned_type as well as
+	c_common_signed_type is the same for both mvl and mvr types.
+
 2012-11-16  Diego Novillo  <dnovillo@google.com>
 
 	Adjust for new vec API (http://gcc.gnu.org/wiki/cxx-conversion/cxx-vec)

gcc/c/c-typeck.c

@@ -5543,8 +5543,10 @@ convert_for_assignment (location_t location, tree type, tree rhs,
       if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
 	  || (target_cmp = comp_target_types (location, type, rhstype))
 	  || is_opaque_pointer
-	  || (c_common_unsigned_type (mvl)
-	      == c_common_unsigned_type (mvr)))
+	  || ((c_common_unsigned_type (mvl)
+	       == c_common_unsigned_type (mvr))
+	      && c_common_signed_type (mvl)
+		 == c_common_signed_type (mvr)))
 	{
 	  if (pedantic
 	      && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)

gcc/testsuite/ChangeLog

+2012-12-18  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/39464
+	* gcc.dg/pr39464.c: New test.
+
 2012-12-18  Ian Lance Taylor  <iant@google.com>
 
 	PR go/55201