https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116854
--- Comment #16 from Uroš Bizjak <ubizjak at gmail dot com> --- (In reply to GGanesh from comment #15) > I wanted to get it confirmed from our BIOS and Kernel developer manuals > (https://www.amd.com/content/dam/amd/en/documents/archived-tech-docs/ > programmer-references/50742_15h_Models_60h-6Fh_BKDG.pdf). > > RDRAND is *supported*/*enabled* for Models 60h-6Fh. > > However, since the latest kernel code is not setting it unconditionally, we > can only rely on the cpuid bits enabled by Kernel. If it is disabled, I > personally feel we need to remove it from the list of ISAs supported by > Excavator in gcc as well. Please note that the kernel patch (referred in Comment #2) says: --quote-- Note, that clearing the RDRAND CPUID bit does not prevent a processor that normally supports the RDRAND instruction from executing it. So any code that determined the support based on family and model won't #UD. --/quote--
