https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116854
--- Comment #3 from Thiago Macieira <thiago at kde dot org> --- (In reply to Andrew Pinski from comment #2) > So bdver4 does have RDRND support just buggy bios's cause linux to disable > it: > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ > ?id=c49a0a80137c7ca7d6ced4c812c9e07a949f6f24 > > > That would mean GCC is doing the right thing really ... > > And why -march=native is working correctly. Just QT breaks because it tries > to decode -march=native into -march=bdver4 without doing the rest. > > So invalid. The bug as reported is invalid, because it reported the wrong thing. The problem has nothing to do with -march=native. The problem is only -march=bdver4, which enables RDRND unconditionally. Since the BIOS and/or OS can disable it, it stands to reason not all Excavators have RDRND. GCC should not enable it unconditionally.
