typedef struct ir_loop ir_loop, *ir_loop_ptr;
typedef struct ir_region ir_region, *ir_region_ptr;
typedef struct ir_reg_tree ir_reg_tree, *ir_reg_tree_ptr;
typedef struct ir_entity ir_entity, *ir_entity_ptr;
typedef struct ir_loop ir_loop, *ir_loop_ptr;
typedef struct ir_region ir_region, *ir_region_ptr;
typedef struct ir_reg_tree ir_reg_tree, *ir_reg_tree_ptr;
typedef struct ir_entity ir_entity, *ir_entity_ptr;