https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84413
--- Comment #1 from Uroš Bizjak <ubizjak at gmail dot com> --- Besides X86_TUNE_USE_BT, there is probably a long list of flags that have to be enabled for m_SKYLAKE_AVX512 (and m_CANNONLAKE and m_ICELAKE). Somebody will have to go through all tune flags for the above mentioned targets.