https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79366
--- Comment #5 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- Annex F makes it an unspecified value (i.e. each execution that occurs in the abstract machine has to act as if it produces some definite value representable in the resulting type, but that value might be different for different executions), with the "invalid" exception raised.
