[Bug middle-end/64491] [5 Regression] incorrect warning: loop exit may only be reached after undefined behavior

[ams at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64491

--- Comment #15 from Andrew Stubbs <ams at gcc dot gnu.org> ---
Yeah, I've not managed to come up with a better solution, so I think I'll just
revert the patch, for now. :-(