#define get_chordal_arch(ce) ((ce)->birg->main_env->arch_env)
#define get_reg(irn) arch_get_irn_register(get_chordal_arch(chordal_env), irn)
#define set_reg(irn, reg) arch_set_irn_register(get_chordal_arch(chordal_env), irn, reg)
#define get_chordal_arch(ce) ((ce)->birg->main_env->arch_env)
#define get_reg(irn) arch_get_irn_register(get_chordal_arch(chordal_env), irn)
#define set_reg(irn, reg) arch_set_irn_register(get_chordal_arch(chordal_env), irn, reg)