re PR c++/13387 (assignment to base class corrupts subclass)

	PR c++/13387
	* cp-lang.c (cxx_get_alias_set): Correct logic for a base type.

From-SVN: r74968

gcc/cp/ChangeLog

+2003-12-23  Nathan Sidwell  <nathan@codesourcery.com>
+
+	PR c++/13387
+	* cp-lang.c (cxx_get_alias_set): Correct logic for a base type.
+
 2003-12-22  Mark Mitchell  <mark@codesourcery.com>
 
 	* decl.c (start_function): Do not check

gcc/cp/cp-lang.c

@@ -292,11 +292,12 @@ ok_to_generate_alias_set_for_type (tree t)
 static HOST_WIDE_INT
 cxx_get_alias_set (tree t)
 {
-  if (CLASS_TYPE_P (t) && TYPE_CONTEXT (t) && CLASS_TYPE_P (TYPE_CONTEXT (t))
+  if (TREE_CODE (t) == RECORD_TYPE
+      && TYPE_CONTEXT (t) && CLASS_TYPE_P (TYPE_CONTEXT (t))
       && CLASSTYPE_AS_BASE (TYPE_CONTEXT (t)) == t)
     /* The base variant of a type must be in the same alias set as the
        complete type.  */
-    t = TYPE_CONTEXT (t);
+    return get_alias_set (TYPE_CONTEXT (t));
   
   if (/* It's not yet safe to use alias sets for some classes in C++.  */
       !ok_to_generate_alias_set_for_type (t)