| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Nathan Bossart <nathandbossart(at)gmail(dot)com> |
| Cc: | David Rowley <dgrowleyml(at)gmail(dot)com>, Ants Aasma <ants(dot)aasma(at)cybertec(dot)at>, Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>, "Amonson, Paul D" <paul(dot)d(dot)amonson(at)intel(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, "Shankaran, Akash" <akash(dot)shankaran(at)intel(dot)com>, Noah Misch <noah(at)leadboat(dot)com>, Matthias van de Meent <boekewurm+postgres(at)gmail(dot)com>, "pgsql-hackers(at)lists(dot)postgresql(dot)org" <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Popcount optimization using AVX512 |
| Date: | 2024-04-08 01:35:39 |
| Message-ID: | 3010179.1712540139@sss.pgh.pa.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
Nathan Bossart <nathandbossart(at)gmail(dot)com> writes:
> On Sun, Apr 07, 2024 at 08:23:32PM -0500, Nathan Bossart wrote:
>> The Intel documentation for _mm256_undefined_si256() [0]
>> indicates that it is intended to return "undefined elements," so it seems
>> like the use of an uninitialized variable might be intentional.
> See also https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=72af61b122.
Ah, interesting. That hasn't propagated to stable distros yet,
evidently (and even when it does, I wonder how soon Coverity
will understand it). Anyway, that does establish that it's
gcc's problem not ours. Thanks for digging!
regards, tom lane
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Peter Geoghegan | 2024-04-08 01:36:17 | Re: Optimizing nbtree ScalarArrayOp execution, allowing multi-column ordered scans, skip scan |
| Previous Message | Andres Freund | 2024-04-08 01:31:43 | Re: Coverity complains about simplehash.h's SH_STAT() |