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Optimize popcount functions with ARM SVE intrinsics.

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This commit introduces SVE implementations of pg_popcount{32,64}.
Unlike the Neon versions, we need an additional configure-time
check to determine if the compiler supports SVE intrinsics, and we
need a runtime check to determine if the current CPU supports SVE
instructions.  Our testing showed that the SVE implementations are
much faster for larger inputs and are comparable to the status
quo for smaller inputs.

Author: "Devanga.Susmitha@fujitsu.com" <Devanga.Susmitha@fujitsu.com>
Co-authored-by: "Chiranmoy.Bhattacharya@fujitsu.com" <Chiranmoy.Bhattacharya@fujitsu.com>
Co-authored-by: "Malladi, Rama" <ramamalladi@hotmail.com>
Reviewed-by: John Naylor <johncnaylorls@gmail.com>
Reviewed-by: Kirill Reshke <reshkekirill@gmail.com>
Discussion: https://postgr.es/m/010101936e4aaa70-b474ab9e-b9ce-474d-a3ba-a3dc223d295c-000000%40us-west-2.amazonses.com
Discussion: https://postgr.es/m/OSZPR01MB84990A9A02A3515C6E85A65B8B2A2%40OSZPR01MB8499.jpnprd01.prod.outlook.com
This commit is contained in:
Nathan Bossart
2025-03-28 16:20:20 -05:00
parent 3c8e463b0d
commit 519338ace4
7 changed files with 475 additions and 6 deletions
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71
configure vendored
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@ -17517,6 +17517,77 @@ $as_echo "#define USE_AVX512_POPCNT_WITH_RUNTIME_CHECK 1" >>confdefs.h
fi
fi
# Check for SVE popcount intrinsics
#
if test x"$host_cpu" = x"aarch64"; then
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for svcnt_x" >&5
$as_echo_n "checking for svcnt_x... " >&6; }
if ${pgac_cv_sve_popcnt_intrinsics+:} false; then :
$as_echo_n "(cached) " >&6
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
#include <arm_sve.h>
char buf[128];
#if defined(__has_attribute) && __has_attribute (target)
__attribute__((target("arch=armv8-a+sve")))
#endif
static int popcount_test(void)
{
svbool_t pred = svptrue_b64();
svuint8_t vec8;
svuint64_t accum1 = svdup_u64(0),
accum2 = svdup_u64(0),
vec64;
char *p = buf;
uint64_t popcnt,
mask = 0x5555555555555555;
vec64 = svand_n_u64_x(pred, svld1_u64(pred, (const uint64_t *) p), mask);
accum1 = svadd_u64_x(pred, accum1, svcnt_u64_x(pred, vec64));
p += svcntb();
vec64 = svand_n_u64_x(pred, svld1_u64(pred, (const uint64_t *) p), mask);
accum2 = svadd_u64_x(pred, accum2, svcnt_u64_x(pred, vec64));
p += svcntb();
popcnt = svaddv_u64(pred, svadd_u64_x(pred, accum1, accum2));
pred = svwhilelt_b8_s32(0, sizeof(buf));
vec8 = svand_n_u8_x(pred, svld1_u8(pred, (const uint8_t *) p), 0x55);
return (int) (popcnt + svaddv_u8(pred, svcnt_u8_x(pred, vec8)));
}
int
main ()
{
return popcount_test();
;
return 0;
}
_ACEOF
if ac_fn_c_try_link "$LINENO"; then :
pgac_cv_sve_popcnt_intrinsics=yes
else
pgac_cv_sve_popcnt_intrinsics=no
fi
rm -f core conftest.err conftest.$ac_objext \
conftest$ac_exeext conftest.$ac_ext
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $pgac_cv_sve_popcnt_intrinsics" >&5
$as_echo "$pgac_cv_sve_popcnt_intrinsics" >&6; }
if test x"$pgac_cv_sve_popcnt_intrinsics" = x"yes"; then
pgac_sve_popcnt_intrinsics=yes
fi
if test x"$pgac_sve_popcnt_intrinsics" = x"yes"; then
$as_echo "#define USE_SVE_POPCNT_WITH_RUNTIME_CHECK 1" >>confdefs.h
fi
fi
# Check for Intel SSE 4.2 intrinsics to do CRC calculations.
#
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for _mm_crc32_u8 and _mm_crc32_u32" >&5