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pgsql: Update configure probes for CFLAGS needed for ARM CRC instructio 6+ messages / 1 participants [nested] [flat]
* pgsql: Update configure probes for CFLAGS needed for ARM CRC instructio @ 2024-11-25 17:50 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 6+ messages in thread From: Tom Lane @ 2024-11-25 17:50 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Update configure probes for CFLAGS needed for ARM CRC instructions. On ARM platforms where the baseline CPU target lacks CRC instructions, we need to supply a -march flag to persuade the compiler to compile such instructions. It turns out that our existing choice of "-march=armv8-a+crc" has not worked for some time, because recent gcc will interpret that as selecting software floating point, and then will spit up if the platform requires hard-float ABI, as most do nowadays. The end result was to silently fall back to software CRC, which isn't very desirable since in practice almost all currently produced ARM chips do have hardware CRC. We can fix this by using "-march=armv8-a+crc+simd" to enable the correct ABI choice. (This has no impact on the code actually generated, since neither of the files we compile with this flag does any floating-point stuff, let alone SIMD.) Keep the test for "-march=armv8-a+crc" since that's required for soft-float ABI, but try that second since most platforms we're likely to build on use hard-float. Since this isn't working as-intended on the last several years' worth of gcc releases, back-patch to all supported branches. Discussion: https://postgr.es/m/4496616.iHFcN1HehY@portable-bastien Branch ------ REL_17_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/e266a0ed67d2fb34c41de11a7cd3f73c66765331 Modified Files -------------- configure | 47 +++++++++++++++++++++++++++++++++++++++++++++-- configure.ac | 8 ++++++-- meson.build | 7 +++++++ 3 files changed, 58 insertions(+), 4 deletions(-) ^ permalink raw reply [nested|flat] 6+ messages in thread
* pgsql: Update configure probes for CFLAGS needed for ARM CRC instructio @ 2024-11-25 17:50 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 6+ messages in thread From: Tom Lane @ 2024-11-25 17:50 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Update configure probes for CFLAGS needed for ARM CRC instructions. On ARM platforms where the baseline CPU target lacks CRC instructions, we need to supply a -march flag to persuade the compiler to compile such instructions. It turns out that our existing choice of "-march=armv8-a+crc" has not worked for some time, because recent gcc will interpret that as selecting software floating point, and then will spit up if the platform requires hard-float ABI, as most do nowadays. The end result was to silently fall back to software CRC, which isn't very desirable since in practice almost all currently produced ARM chips do have hardware CRC. We can fix this by using "-march=armv8-a+crc+simd" to enable the correct ABI choice. (This has no impact on the code actually generated, since neither of the files we compile with this flag does any floating-point stuff, let alone SIMD.) Keep the test for "-march=armv8-a+crc" since that's required for soft-float ABI, but try that second since most platforms we're likely to build on use hard-float. Since this isn't working as-intended on the last several years' worth of gcc releases, back-patch to all supported branches. Discussion: https://postgr.es/m/4496616.iHFcN1HehY@portable-bastien Branch ------ REL_15_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/851c6ff18fd359bebd97b7f2b73bb46981a1a8d2 Modified Files -------------- configure | 47 +++++++++++++++++++++++++++++++++++++++++++++-- configure.ac | 8 ++++++-- 2 files changed, 51 insertions(+), 4 deletions(-) ^ permalink raw reply [nested|flat] 6+ messages in thread
* pgsql: Update configure probes for CFLAGS needed for ARM CRC instructio @ 2024-11-25 17:50 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 6+ messages in thread From: Tom Lane @ 2024-11-25 17:50 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Update configure probes for CFLAGS needed for ARM CRC instructions. On ARM platforms where the baseline CPU target lacks CRC instructions, we need to supply a -march flag to persuade the compiler to compile such instructions. It turns out that our existing choice of "-march=armv8-a+crc" has not worked for some time, because recent gcc will interpret that as selecting software floating point, and then will spit up if the platform requires hard-float ABI, as most do nowadays. The end result was to silently fall back to software CRC, which isn't very desirable since in practice almost all currently produced ARM chips do have hardware CRC. We can fix this by using "-march=armv8-a+crc+simd" to enable the correct ABI choice. (This has no impact on the code actually generated, since neither of the files we compile with this flag does any floating-point stuff, let alone SIMD.) Keep the test for "-march=armv8-a+crc" since that's required for soft-float ABI, but try that second since most platforms we're likely to build on use hard-float. Since this isn't working as-intended on the last several years' worth of gcc releases, back-patch to all supported branches. Discussion: https://postgr.es/m/4496616.iHFcN1HehY@portable-bastien Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/5980f1884fc911af120c98ad440b9546ed9012c5 Modified Files -------------- configure | 47 +++++++++++++++++++++++++++++++++++++++++++++-- configure.ac | 8 ++++++-- meson.build | 7 +++++++ 3 files changed, 58 insertions(+), 4 deletions(-) ^ permalink raw reply [nested|flat] 6+ messages in thread
* pgsql: Update configure probes for CFLAGS needed for ARM CRC instructio @ 2024-11-25 17:50 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 6+ messages in thread From: Tom Lane @ 2024-11-25 17:50 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Update configure probes for CFLAGS needed for ARM CRC instructions. On ARM platforms where the baseline CPU target lacks CRC instructions, we need to supply a -march flag to persuade the compiler to compile such instructions. It turns out that our existing choice of "-march=armv8-a+crc" has not worked for some time, because recent gcc will interpret that as selecting software floating point, and then will spit up if the platform requires hard-float ABI, as most do nowadays. The end result was to silently fall back to software CRC, which isn't very desirable since in practice almost all currently produced ARM chips do have hardware CRC. We can fix this by using "-march=armv8-a+crc+simd" to enable the correct ABI choice. (This has no impact on the code actually generated, since neither of the files we compile with this flag does any floating-point stuff, let alone SIMD.) Keep the test for "-march=armv8-a+crc" since that's required for soft-float ABI, but try that second since most platforms we're likely to build on use hard-float. Since this isn't working as-intended on the last several years' worth of gcc releases, back-patch to all supported branches. Discussion: https://postgr.es/m/4496616.iHFcN1HehY@portable-bastien Branch ------ REL_16_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/1f4aadec41b8655e4e37c18c3c11552091ef7123 Modified Files -------------- configure | 47 +++++++++++++++++++++++++++++++++++++++++++++-- configure.ac | 8 ++++++-- meson.build | 7 +++++++ 3 files changed, 58 insertions(+), 4 deletions(-) ^ permalink raw reply [nested|flat] 6+ messages in thread
* pgsql: Update configure probes for CFLAGS needed for ARM CRC instructio @ 2024-11-25 17:50 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 6+ messages in thread From: Tom Lane @ 2024-11-25 17:50 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Update configure probes for CFLAGS needed for ARM CRC instructions. On ARM platforms where the baseline CPU target lacks CRC instructions, we need to supply a -march flag to persuade the compiler to compile such instructions. It turns out that our existing choice of "-march=armv8-a+crc" has not worked for some time, because recent gcc will interpret that as selecting software floating point, and then will spit up if the platform requires hard-float ABI, as most do nowadays. The end result was to silently fall back to software CRC, which isn't very desirable since in practice almost all currently produced ARM chips do have hardware CRC. We can fix this by using "-march=armv8-a+crc+simd" to enable the correct ABI choice. (This has no impact on the code actually generated, since neither of the files we compile with this flag does any floating-point stuff, let alone SIMD.) Keep the test for "-march=armv8-a+crc" since that's required for soft-float ABI, but try that second since most platforms we're likely to build on use hard-float. Since this isn't working as-intended on the last several years' worth of gcc releases, back-patch to all supported branches. Discussion: https://postgr.es/m/4496616.iHFcN1HehY@portable-bastien Branch ------ REL_14_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/2fc0199a5015b520da75dddb76a169f6a568ef12 Modified Files -------------- configure | 47 +++++++++++++++++++++++++++++++++++++++++++++-- configure.ac | 8 ++++++-- 2 files changed, 51 insertions(+), 4 deletions(-) ^ permalink raw reply [nested|flat] 6+ messages in thread
* pgsql: Update configure probes for CFLAGS needed for ARM CRC instructio @ 2024-11-25 17:50 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 6+ messages in thread From: Tom Lane @ 2024-11-25 17:50 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Update configure probes for CFLAGS needed for ARM CRC instructions. On ARM platforms where the baseline CPU target lacks CRC instructions, we need to supply a -march flag to persuade the compiler to compile such instructions. It turns out that our existing choice of "-march=armv8-a+crc" has not worked for some time, because recent gcc will interpret that as selecting software floating point, and then will spit up if the platform requires hard-float ABI, as most do nowadays. The end result was to silently fall back to software CRC, which isn't very desirable since in practice almost all currently produced ARM chips do have hardware CRC. We can fix this by using "-march=armv8-a+crc+simd" to enable the correct ABI choice. (This has no impact on the code actually generated, since neither of the files we compile with this flag does any floating-point stuff, let alone SIMD.) Keep the test for "-march=armv8-a+crc" since that's required for soft-float ABI, but try that second since most platforms we're likely to build on use hard-float. Since this isn't working as-intended on the last several years' worth of gcc releases, back-patch to all supported branches. Discussion: https://postgr.es/m/4496616.iHFcN1HehY@portable-bastien Branch ------ REL_13_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/32057a0f791e865df4ea5cd05ac336ef7e6f99f5 Modified Files -------------- configure | 47 +++++++++++++++++++++++++++++++++++++++++++++-- configure.in | 8 ++++++-- 2 files changed, 51 insertions(+), 4 deletions(-) ^ permalink raw reply [nested|flat] 6+ messages in thread
end of thread, other threads:[~2024-11-25 17:50 UTC | newest] Thread overview: 6+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2024-11-25 17:50 pgsql: Update configure probes for CFLAGS needed for ARM CRC instructio Tom Lane <tgl@sss.pgh.pa.us> 2024-11-25 17:50 pgsql: Update configure probes for CFLAGS needed for ARM CRC instructio Tom Lane <tgl@sss.pgh.pa.us> 2024-11-25 17:50 pgsql: Update configure probes for CFLAGS needed for ARM CRC instructio Tom Lane <tgl@sss.pgh.pa.us> 2024-11-25 17:50 pgsql: Update configure probes for CFLAGS needed for ARM CRC instructio Tom Lane <tgl@sss.pgh.pa.us> 2024-11-25 17:50 pgsql: Update configure probes for CFLAGS needed for ARM CRC instructio Tom Lane <tgl@sss.pgh.pa.us> 2024-11-25 17:50 pgsql: Update configure probes for CFLAGS needed for ARM CRC instructio Tom Lane <tgl@sss.pgh.pa.us>
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