[Bug c++/70361] Obviously false code in if not detected

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70361

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
-Wunreachable-code does nothing now and has not for a few years now.  Support
for it was removed as it provided too many false positives.