On Fri, Jun 16, 2023 at 8:28 AM YANG Xudong <yangxud...@ymatrix.cn> wrote: > > +# If the intrinsics are supported, sets pgac_loongarch_crc32c_intrinsics, > > +# and CFLAGS_CRC. > > > > +# Check if __builtin_loongarch_crcc_* intrinsics can be used > > +# with the default compiler flags. > > +# CFLAGS_CRC is set if the extra flag is required. > > > > Same here -- it seems we don't need to set CFLAGS_CRC at all. Can you > > confirm? > > > > We don't need to set CFLAGS_CRC as commented. I have updated the > configure script to make it align with the logic in meson build script.
(Looking again at v2) The compilation test is found in c-compiler.m4, which still has all logic for CFLAGS_CRC, including saving and restoring the old CFLAGS. Can this also be simplified? I diff'd pg_crc32c_loongarch.c with the current other files, and found it is structurally the same as the Arm implementation. That's logical if memory alignment is important. /* - * ARMv8 doesn't require alignment, but aligned memory access is - * significantly faster. Process leading bytes so that the loop below - * starts with a pointer aligned to eight bytes. + * Aligned memory access is significantly faster. + * Process leading bytes so that the loop below starts with a pointer aligned to eight bytes. Can you confirm the alignment requirement -- it's not clear what the intention is since "doesn't require" wasn't carried over. Is there any documentation (or even a report in some other context) about aligned vs unaligned memory access performance? -- John Naylor EDB: http://www.enterprisedb.com
