[Bug fortran/83235] IAND sometimes doesn't take bitwise-and of sign bit with -O2

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83235

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
That is a bad understanding of what undefined behavior means.  After you invoke
undefined behavior anywhere in your program, anything can happen, there are no
constraints on what can happen.