https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89929
--- Comment #16 from Nikolay Bogoychev <nheart at gmail dot com> --- Created attachment 46187 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46187&action=edit target("arch=foo") doesn't work (In reply to Martin Liška from comment #15) > @Nikolay: > > As discussed in https://gcc.gnu.org/ml/gcc-patches/2019-04/msg00416.html > email thread, we reached the following consensus with H.J: > > - As any AVX512 extensions (apart from AVX512F) can be enabled individually, > it's difficult to come up with priorities in dispatcher. > - We don't have a syntax for target_clone attribute where one would say e.g. > avx512f+avx512cd+avx512er. > - So that we would reject these (AVX512* except AVX512F) in target_clone > attribute and we recommend to use rather. > target_clones(arch=skylake,arch=skylake-avx512,arch=cannonlake,arch=icelake- > client,arch=icelake-server, ..) > - Using that one can cover used AVX512 ISA combinations for existing CPUs > > Does it work for you Nikolay? @Martin: Thank you for the detailed answer. This could work for now. I have a few questions about it: Wouldn't that create issues in the future if AMD decide to release avx512 for their CPUs? In case we are using C style target annotation (and not function multi-versioning), should we also use target(arch=skylake-avx512) instead of target(avx512bw)? Also it seems that target("arch=foo") fails for my simple example with target specific option mismatch error (but works in clang). If I change target to avx2 it compiles again. Cheers, Nick
