4b03a27faf
Presently, we check for compiler support for the required intrinsics both with and without the -msse4.2 compiler flag, and then depending on the results of those checks, we pick which files to compile with which flags. This is tedious and complicated, and it results in unsustainable coding patterns such as separate files for each portion of code that may need to be built with different compiler flags. This commit makes use of the newly-added support for __attribute__((target(...))) in the SSE4.2 CRC-32C code. This simplifies both the configure-time checks and the build scripts, and it allows us to place the functions that use the intrinsics in files that we otherwise do not want to build with special CPU instructions (although this commit refrains from doing so). This is also preparatory work for a proposed follow-up commit that will further optimize the CRC-32C code with AVX-512 instructions. While at it, this commit modifies meson's checks for SSE4.2 CRC support to be the same as autoconf's. meson was choosing whether to use a runtime check based purely on whether -msse4.2 is required, while autoconf has long checked for the __SSE4_2__ preprocessor symbol to decide. meson's previous approach seems to work just fine, but this change avoids needing to build multiple test programs and to keep track of whether to actually use pg_attribute_target(). Ideally we'd use __attribute__((target(...))) for ARMv8 CRC support, too, but there's little point in doing so because until clang 16, using the ARM intrinsics still requires special compiler flags. Perhaps we can re-evaluate this decision after some time has passed. Author: Raghuveer Devulapalli Discussion: https://postgr.es/m/PH8PR11MB8286BE735A463468415D46B5FB5C2%40PH8PR11MB8286.namprd11.prod.outlook.com
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.