You are right that there are cases where it is not possible. But it also works when arguments are not passed in registers. The condition then is that there are

You are right that there are cases where it is not possible. But it also works when arguments are not passed in registers. The condition then is that there are less stack slots used than in the caller. https://godbolt.org/z/M4Eqzh3YE https://godbolt.org/z/M4Eqzh3YE