https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80728
--- Comment #8 from Alexander Monakov <amonakov at gcc dot gnu.org> --- Honza: ping :). ipa-pure-const might be a better place to mark functions with compiler memory barriers, as it already computes and propagates "nonfreeing" property (thus computing "nonbarrier" in ipa-pure-const would allow to use it in implementation of nonbarrier_call_p). OTOH ipa-pure-const is optional, so with -fno-ipa-pure-const, ipa-reference would see most functions as compiler memory barriers. Although it's possible to rescan bodies of those functions that ipa-pure-const did not scan, that seems undesirable.