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Optimize popcount functions with ARM Neon intrinsics.

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This commit introduces Neon implementations of pg_popcount{32,64},
pg_popcount(), and pg_popcount_masked().  As in simd.h, we assume
that all available AArch64 hardware supports Neon, so we don't need
any new configure-time or runtime checks.  Some compilers already
emit Neon instructions for these functions, but our hand-rolled
implementations for pg_popcount() and pg_popcount_masked()
performed better in testing, likely due to better instruction-level
parallelism.

Author: "Chiranmoy.Bhattacharya@fujitsu.com" <Chiranmoy.Bhattacharya@fujitsu.com>
Reviewed-by: John Naylor <johncnaylorls@gmail.com>
Discussion: https://postgr.es/m/010101936e4aaa70-b474ab9e-b9ce-474d-a3ba-a3dc223d295c-000000%40us-west-2.amazonses.com
This commit is contained in:
Nathan Bossart
2025-03-28 14:49:35 -05:00
parent 51a0382e8d
commit 6be53c2767
5 changed files with 235 additions and 6 deletions
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9
src/include/port/pg_bitutils.h
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@ -298,6 +298,15 @@ pg_ceil_log2_64(uint64 num)
#endif
#endif
/*
* On AArch64, we can use Neon instructions if the compiler provides access to
* them (as indicated by __ARM_NEON). As in simd.h, we assume that all
* available 64-bit hardware has Neon support.
*/
#if defined(__aarch64__) && defined(__ARM_NEON)
#define POPCNT_AARCH64 1
#endif
#ifdef TRY_POPCNT_X86_64
/* Attempt to use the POPCNT instruction, but perform a runtime check first */
extern PGDLLIMPORT int (*pg_popcount32) (uint32 word);