[Bug c/80341] gcc miscompiles division of signed char

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80341

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
With -O I get
x.c: In function ‘foo’:
x.c:7:7: warning: overflow in implicit constant conversion [-Woverflow]
   s = (unsigned short) c / -55;
       ^