Fix r15829.

[r15838]

ir/ir/iropt.c

@@ -3432,10 +3432,9 @@ static ir_node *transform_node_Proj_Cmp(ir_node *proj) {
 		if (get_mode_size_bits(mode) > get_mode_size_bits(op_mode) &&
 				(mode_is_signed(mode) || !mode_is_signed(op_mode))) {
 			ir_node  *null  = new_Const(op_mode, get_mode_null(op_mode));
-			dbg_info *dbg   = get_irn_dbg_info(n);
-			ir_graph *irg   = current_ir_graph;
-			ir_node  *block = get_nodes_block(n);
-			return new_rd_Cmp(dbg, irg, block, op, null);
+			set_Cmp_left( n, op);
+			set_Cmp_right(n, null);
+			return proj;
 		}
 	}