https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117327
--- Comment #4 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
The problem is in find_end_label, namely:
/* Otherwise, see if there is a label at the end of the function. If there
is, it must be that RETURN insns aren't needed, so that is our return
label and we don't have to do anything else. */
That was correct 20 years ago (by the time of PR boottstrap/16326) but no
longer is because of __builtin_unreachable and the like.
