https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122555
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- . Note clang does not warn here as it considers (-= 1) as an use even though it does not considers ++ an use. I wonder if that is why the code uses -= 1 to get around the warning rather than removing the variable.
