https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83546
Bug ID: 83546 Summary: -march=silvermont doesn't enable rdrnd by default despite what docs say Product: gcc Version: 8.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: craig.topper at gmail dot com Target Milestone: --- The documentation https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html says 'silvermont' enables rdrnd, but that doesn't appear to happen. I think it may have worked in r205275 when 'slm' listed all of its features separately. But I think it was then broken in r206178 when PTA_SILVERMONT was introduced and defined like this #define PTA_SILVERMONT \ (PTA_WESTMERE | PTA_MOVBE) PTA_WESTMERE doesn't and shouldn't include RDRND.