From: John Naylor <john.naylor@postgresql.org>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Properly fix AVX-512 CRC calculation bug
Date: Mon, 23 Jun 2025 11:05:59 +0000
Message-ID: <E1uTezv-002yZk-0B@gemulon.postgresql.org> (raw)
Properly fix AVX-512 CRC calculation bug
The problem that led to the workaround in f83f14881c7 was not in fact
a compiler bug, but a failure to zero the upper bits of the vector
register containing the initial scalar CRC value. Fix that and revert
the workaround.
Diagnosed-by: Nathan Bossart <nathandbossart@gmail.com>
Diagnosed-by: Raghuveer Devulapalli <raghuveer.devulapalli@intel.com>
Tested-by: Andy Fan <zhihuifan1213@163.com>
Tested-by: Soumyadeep Chakraborty <soumyadeep2007@gmail.com>
Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Reviewed-by: Raghuveer Devulapalli <raghuveer.devulapalli@intel.com>
Discussion: https://postgr.es/m/PH8PR11MB82866B07AA6758D12F699C00FB70A@PH8PR11MB8286.namprd11.prod.outlook.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/43da394304fba820830da2cef2c0214fe292c037
Modified Files
--------------
src/port/pg_crc32c_sse42.c | 2 +-
src/port/pg_crc32c_sse42_choose.c | 4 +---
2 files changed, 2 insertions(+), 4 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: john.naylor@postgresql.org, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Properly fix AVX-512 CRC calculation bug
In-Reply-To: <E1uTezv-002yZk-0B@gemulon.postgresql.org>
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