for(pos=-1; pos<max; ++pos) {
arch_get_register_req(aenv, &req, irn, pos);
/* if a restriction is found, insert a perm before the irn */
for(pos=-1; pos<max; ++pos) {
arch_get_register_req(aenv, &req, irn, pos);
/* if a restriction is found, insert a perm before the irn */