RE: Popcount optimization using AVX512

Won't I still need the runtime checks? If I compile with a compiler supporting the HW "feature" but run on HW without
thatfeature,  I will want to avoid faults due to illegal operations. Won't that also affect performance? 

Paul

> -----Original Message-----
> From: Nathan Bossart <nathandbossart@gmail.com>
> Sent: Monday, March 18, 2024 8:29 AM
> To: David Rowley <dgrowleyml@gmail.com>
> Cc: Amonson, Paul D <paul.d.amonson@intel.com>; Andres Freund
> <andres@anarazel.de>; Alvaro Herrera <alvherre@alvh.no-ip.org>; Shankaran,
> Akash <akash.shankaran@intel.com>; Noah Misch <noah@leadboat.com>;
> Tom Lane <tgl@sss.pgh.pa.us>; Matthias van de Meent
> <boekewurm+postgres@gmail.com>; pgsql-hackers@lists.postgresql.org
> Subject: Re: Popcount optimization using AVX512
>
> On Mon, Mar 18, 2024 at 09:56:32AM +1300, David Rowley wrote:
> > Maybe it's worth exploring something along the lines of the attached
> > before doing the AVX512 stuff.  It seems like a pretty good speed-up
> > and will apply for CPUs without AVX512 support.
>
> +1
>
> --
> Nathan Bossart
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