class.c (build_vtable_entry_ref): Subtract in char*, not ptrdiff_t.

        * class.c (build_vtable_entry_ref): Subtract in char*, not
        ptrdiff_t.

Co-Authored-By: Jason Merrill <jason@redhat.com>

From-SVN: r45284

gcc/cp/ChangeLog

+2001-08-30  Joern Rennecke <amylaar@redhat.com>
+	    Jason Merrill  <jason_merrill@redhat.com>
+
+	* class.c (build_vtable_entry_ref): Subtract in char*, not
+	ptrdiff_t.
+
 2001-08-23  Jason Merrill  <jason_merrill@redhat.com>
 
 	* tree.c (cp_build_qualified_type_real): Use get_qualified_type.

gcc/cp/class.c

@@ -444,9 +444,12 @@ build_vtable_entry_ref (basetype, idx)
   s = build_tree_list (build_string (1, "s"), s);
 
   i = build_array_ref (first_fn, idx);
-  i = build_c_cast (ptrdiff_type_node, build_unary_op (ADDR_EXPR, i, 0));
+  /* We must not convert to ptrdiff_type node here, since this could widen
+     from a partial to an integral node, which would create a
+     convert_expression that would be in the way of any simplifications.  */
+  i = build_c_cast (string_type_node, build_unary_op (ADDR_EXPR, i, 0));
   i2 = build_array_ref (vtable, build_int_2 (0,0));
-  i2 = build_c_cast (ptrdiff_type_node, build_unary_op (ADDR_EXPR, i2, 0));
+  i2 = build_c_cast (string_type_node, build_unary_op (ADDR_EXPR, i2, 0));
   i = cp_build_binary_op (MINUS_EXPR, i, i2);
   i = build_tree_list (build_string (1, "i"), i);