http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59615
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> --- But it would warn about it with -Wsign-compare. You want unsigned r = (unsigned) a + b; or similar to avoid undefined behavior if there is a possibility of signed integer overflow. Anyway, you definitely don't want to use inline asm in this case, if there is some code GCC doesn't optimize as good as you'd like to, just report that.
