-/* Exchanges two nodes by conserving edges leaving old (i.e., pointers
- pointing to old). Turns the old node into an Id. Requires that
- current_ir_graph is set properly. */
-inline void exchange (ir_node *old, ir_node *new);
+/** Turns a node into a "useless" Tuple.
+ *
+ * Turns a node into a "useless" Tuple. The Tuple node just forms a tuple
+ * from several inputs. The predecessors of the tuple have to be
+ * set by hand. The block predecessor automatically remains the same.
+ * This is useful if a node returning a tuple is removed, but the Projs
+ * extracting values from the tuple are not available.
+ *
+ * @param node The node to be turned into a tuple.
+ * @param arity The number of values formed into a Tuple.
+ */
+void turn_into_tuple (ir_node *node, int arity);