[Bug c/117549] Miscompile with -O0 and -O1/2/3

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117549

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
See https://c-faq.com/expr/seqpoints.html and
https://en.cppreference.com/w/c/language/eval_order .