https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104688
--- Comment #26 from Alexander Monakov <amonakov at gcc dot gnu.org> --- Sure, the right course of action seems to be to simply document that atomic types and built-ins are meant to be used on "common" (writeback) memory, and no guarantees can be given otherwise, because it would involve platform specifics (relaxed ordering of WC writes as you say; tearing by PCI bridges and device interfaces seems like another possible caveat).
