[Bug c/79979] For loop fails to exit

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79979

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Please read e.g. http://blog.regehr.org/archives/213 or other articles about UB
and just fix your code.