+ (assert(off > 0 && "Invalid node data offset"), (type *) ((char *) (node) - (off)))
+
+/**
+ * Get the pointer to the node some custom data belongs to.
+ * @param data The pointer to the custom data.
+ * @param off The number as returned by register_additional_node_data().
+ * @return A pointer to the ir node the custom data belongs to.
+ */
+#define get_irn_data_base(data,off) \
+ (assert(off > 0 && "Invalid node data offset"), (ir_node *) ((char *) (data) + (off)))