Horton

Properly fix AVX-512 CRC calculation bug

John Naylor <john.naylor@postgresql.org>

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Commit: 43da394304fba820830da2cef2c0214fe292c037
Author: John Naylor <john.naylor@postgresql.org>
Date: 2025-06-23T11:03:56Z
Releases: 18.0 
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

Files

PathChange+/−
src/port/pg_crc32c_sse42.c modified +1 −1
src/port/pg_crc32c_sse42_choose.c modified +1 −3

Discussion