void set_irg_loop(ir_graph *irg, ir_loop *l);
/* Returns the root loop info (if exists) for an irg. */
-ir_loop *get_irg_loop(ir_graph *irg);
+ir_loop *get_irg_loop(const ir_graph *irg);
/** Returns the loop n is contained in. NULL if node is in no loop. */
ir_loop *get_irn_loop(const ir_node *n);
ir_loop *get_loop_son(ir_loop *loop, int pos);
/** Returns the number of nodes contained in loop. */
-int get_loop_n_nodes(ir_loop *loop);
+int get_loop_n_nodes(const ir_loop *loop);
/** Returns the pos`th ir_node of a loop.
Returns NULL if there is not a pos`th ir_node. */
-ir_node *get_loop_node(ir_loop *loop, int pos);
+ir_node *get_loop_node(const ir_loop *loop, int pos);
/** Returns the number of elements contained in loop. */
int get_loop_n_elements(const ir_loop *loop);