https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106783
--- Comment #6 from Jan Hubicka <hubicka at gcc dot gnu.org> --- The problem is that n/=0 is undefined behavior (so we can optimize out call to function doing divide by zero), while __builtin_trap is observable and we do not optimize out code paths that may trip to it. so isolate-paths is de-facto pesimizing code from this POV. It is used __builtin_unreachable things would work. I think some parts of compiler use __builtin_unreachable (such as loop unrolling) other __builtin_trap. It would be nice to have consistent solution to this.
