https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90648
--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> --- At least __builtin_*_overflow{,_p} verify the arguments and don't let bogus ones through. As for internal functions, those indeed can't be verified, but they are compiler constructed and the compiler should ensure during construction that they are sane.