+/**
+ * Calculate a hash value of a node.
+ * The hash value is calculated from the nodes predecessors.
+ * Special handling for Const and SymConst nodes (these don't have predecessors).
+ *
+ * @param node The IR-node
+ */
+unsigned ir_node_hash(ir_node *node);
+
+/**
+ * Creates a new value table used for storing CSE identities.
+ * The value table is used to identify common expressions.
+ *
+ */
+pset *new_identities(void);