irg_block_walk_graph(irg, construct_block_livethrough_unused, construct_loop_edges, &env);
construct_loop_livethrough_unused(&env, get_irg_loop(irg));
irg_block_walk_graph(irg, construct_block_livethrough_unused, construct_loop_edges, &env);
construct_loop_livethrough_unused(&env, get_irg_loop(irg));