https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97989
--- Comment #17 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Looks like a bad idea to me. And, I think gcc had this behavior for -g3 and -P years before clang implemented those, so arguing here about clang-compatibility is strange. clang simply decided not to implement the documented switches the way they were documented.
