[Bug tree-optimization/60229] wrong code at -O2 and -O3 on x86_64-linux-gnu

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60229

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note there is no overflow happening here at all.  In that a++ is the same as a
= a + 1 which is the same as a = (short)(((int)a) + 1) due to promotion rules
in C.