Improved 21ff67fb03f6a597f78ea76b77af206d8ad17e1a.

Make an if instead of a #if 0 on "broken" code and add an comment
that explains why the non-wroken code is not used now.

ir/tr/trverify.c

@@ -153,7 +153,7 @@ static void show_ent_overwrite_cnt(ir_entity *ent)
  */
 static int check_class(ir_type *tp)
 {
-	size_t i, n, j, m;
+	size_t i, n;
 
 	for (i = 0, n = get_class_n_members(tp); i < n; ++i) {
 		ir_entity *mem = get_class_member(tp, i);
@@ -178,7 +178,10 @@ static int check_class(ir_type *tp)
 			show_ent_overwrite_cnt(mem)
 		);
 
-#if 0
+		if (false) {
+			size_t j, m;
+			/* check if the overwrite relation is flat, i.e. every overwrite
+			 * is visible in every direct superclass. */
 			for (j = 0, m = get_entity_n_overwrites(mem); j < m; ++j) {
 				ir_entity *ovw = get_entity_overwrites(mem, j);
 				size_t    k, n_super;
@@ -197,8 +200,7 @@ static int check_class(ir_type *tp)
 					}
 				}
 			}
-#endif
-
+		}
 	}
 	return 0;
 }