https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79173
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> --- (In reply to Michael_S from comment #5) > I agree with regard to "other targets", first of all, aarch64, but x86_64 > variant of gcc already provides requested functionality in for of > _subborrow_u64 () and _addcarry_u64() intrinsic functions. > The problem here is not lack of functionality, but very poor implementation > (mentioned many times on bugzilla with minimal effect). > In that regard gcc is more than decade behind MSVC and ~4 years behind > clang/llvm. Surprisingly, icc is also quite bad. Are you sure you have tested gcc trunk? There have been fixes for this a month ago as part of PR97387 fixes.