+/**
+ * The compute value operation.
+ * This operation evaluates an IR node into a tarval if possible,
+ * returning tarval_bad otherwise.
+ */
+typedef tarval *(*computed_value_func)(ir_node *n);
+
+/**
+ * The equivalent node operation.
+ * This operation returns an equivalent node for the input node.
+ * It does not create new nodes. It is therefore safe to free n
+ * if the node returned is not n.
+ * If a node returns a Tuple we can not just skip it. If the size of the
+ * in array fits, we transform n into a tuple (e.g., possible for Div).
+ */
+typedef ir_node *(*equivalent_node_func)(ir_node *n);
+
+/**
+ * The transform node operation.
+ * This operation tries several [inplace] [optimizing] transformations
+ * and returns an equivalent node.
+ * The difference to equivalent_node() is that these
+ * transformations _do_ generate new nodes, and thus the old node must
+ * not be freed even if the equivalent node isn't the old one.
+ */
+typedef ir_node *(*transform_node_func)(ir_node *n);
+
+/**
+ * The node attribute compare operation.
+ * Compares the nodes attributes of two nodes of identical opcode
+ * and returns 0 if the attributes are identical, 1 if they differ.
+ */
+typedef int (*node_cmp_attr_func)(ir_node *a, ir_node *b);
+
+/**
+ * The reassociation operation.
+ * Called from a walker. Returns non-zero if
+ * a reassociation rule was applied.
+ */
+typedef int (*reassociate_func)(ir_node *n);
+
+/**
+ * The copy attribute operation.
+ * Copy the node attributes from a 'old' node to a 'new' one.
+ */
+typedef void (*copy_attr_func)(const ir_node *old_node, ir_node *new_node);
+
+/** The type of an ir_op. */