If adding two ints overflows, it doesn't matter whether the result will
be stored in an unsigned or not; and checking afterwards does not make it
retroactively defined.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
(cherry picked from commit 28a078eded1c29985ed078b59d48ff59cf00394b)
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>