https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109945
--- Comment #31 from Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> --- Oops, I guess my reading did disagree with jwakely's in one small point: jwakely writes-- > But since one of the pointers is an invalid pointer, > you can't do anything with its value anyway, including > comparing it to &w. In my interpretation, it was fine to compare `global == &w`; but the boolean value of that comparison would be unspecified (because `*global` was out-of-lifetime), and even if it *did* happen to come out to `true`, it would still be UB to execute `global->i = 42` (because `*global` would still be a different object from `w`, and `*global` is out-of-lifetime). I think this makes no difference to the ultimate conclusion, i.e. something here ends up being UB either way.
