-FIRM_IMPL2_VOID(sched_add_after, ir_node *, ir_node *)
-FIRM_IMPL2_VOID(sched_add_before, ir_node *, ir_node *)
-FIRM_IMPL1_VOID(sched_init_block, ir_node *)
-FIRM_IMPL1_VOID(sched_reset, ir_node *)
+FIRM_IMPL2_VOID(sched_add_after, const ir_node *, const ir_node *)
+FIRM_IMPL2_VOID(sched_add_before, const ir_node *, const ir_node *)
+FIRM_IMPL1_VOID(sched_init_block, const ir_node *)
+FIRM_IMPL1_VOID(sched_reset, const ir_node *)