Re: Popcount optimization using AVX512

On Tue, Jul 30, 2024 at 07:43:08PM -0700, Andres Freund wrote:
> On 2024-07-30 21:01:31 -0500, Nathan Bossart wrote:
>> The main purpose of the XSAVE compiler check is to determine whether we
>> need to add -mxsave in order to use _xgetbv() [0].  If that wasn't a
>> factor, we could probably skip it.  Earlier versions of the patch used
>> inline assembly in the non-MSVC path to call XGETBV, which I was trying to
>> avoid.
> 
> My point is that _xgetbv() is made available by -mavx512vpopcntdq -mavx512bw
> alone, without needing -mxsave:

Oh, I see.  I'll work on a patch to remove that compiler check, then...

-- 
nathan