https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85120
Bug ID: 85120 Summary: __get_cpuid Product: gcc Version: 8.0 Status: UNCONFIRMED Keywords: missed-optimization Severity: normal Priority: P3 Component: libgcc Assignee: unassigned at gcc dot gnu.org Reporter: fw at gcc dot gnu.org Target Milestone: --- Target: i686 __get_cpuid performs the EFLAGS check even with -march=x86-64. I think the instruction was introduced with the Pentium, so we can avoid the check when compiling with -march=i586.