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 that feature, I will want to avoid faults due to illegal operations. Won't that also affect performance?

Paul

> -----Original Message-----
> From: Nathan Bossart <nathandbossart(at)gmail(dot)com>
> Sent: Monday, March 18, 2024 8:29 AM
> To: David Rowley <dgrowleyml(at)gmail(dot)com>
> Cc: Amonson, Paul D <paul(dot)d(dot)amonson(at)intel(dot)com>; Andres Freund
> <andres(at)anarazel(dot)de>; Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>; Shankaran,
> Akash <akash(dot)shankaran(at)intel(dot)com>; Noah Misch <noah(at)leadboat(dot)com>;
> Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>; Matthias van de Meent
> <boekewurm+postgres(at)gmail(dot)com>; pgsql-hackers(at)lists(dot)postgresql(dot)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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