https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100347
--- Comment #8 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #7)
> (In reply to Iru Cai from comment #6)
> > I've checked host_detect_local_cpu() in gcc/config/i386/driver-i386.c. GCC
> > detects x86 host CPU micro architecture by cpuid instruction instead of the
> > APIs provided by the OS.
>
> But there shouldn't have been any functional changes in the code 10.x vs.
> 11.x
>
> Erik - does GCC 10.3 actually still work? Thus, isn't it maybe some OS
> restriction on CPUID access, maybe a difference in whether the GCC binaries
> are signed or not?
>
> I wonder if you can try
>
> int main()
> {
> __builtin_cpu_init ();
> return __builtin_cpu_is ("skylake");
> }
>
> with both compilers?
I recently went through the exercise of finding out what -march=native reported
for me across the machines I use for testing - AFAIR the Xeon W reported
cascadelake, and corei7s reported skyline, ivybridge or haswell. I will need
to recheck.
Are you on Darwin20 / macOS11 .. it seems that Apple are gradually trying to
tie things down more in line with iOS - however, I have not seen too much of
that on x86_64 - more on the Arm64 side.
I'll need a few days to check this out.
