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| author | H.J. Lu <hjl.tools@gmail.com> | 2023-08-17 09:42:29 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2023-08-21 10:44:26 -0700 |
| commit | a8ecb126d4c26c52f4ad828c566afe4043a28155 (patch) | |
| tree | bfab51ea467c0717fc322be816770598edfcca63 /sysdeps/x86_64/fpu | |
| parent | ce99601fa883a8916cb902c7bcd2125046a4a39d (diff) | |
| download | glibc-a8ecb126d4c26c52f4ad828c566afe4043a28155.tar glibc-a8ecb126d4c26c52f4ad828c566afe4043a28155.tar.gz glibc-a8ecb126d4c26c52f4ad828c566afe4043a28155.tar.bz2 glibc-a8ecb126d4c26c52f4ad828c566afe4043a28155.zip | |
x86_64: Add log1p with FMA
On Skylake, it changes log1p bench performance by:
Before After Improvement
max 63.349 58.347 8%
min 4.448 5.651 -30%
mean 12.0674 10.336 14%
The minimum code path is
if (hx < 0x3FDA827A) /* x < 0.41422 */
{
if (__glibc_unlikely (ax >= 0x3ff00000)) /* x <= -1.0 */
{
...
}
if (__glibc_unlikely (ax < 0x3e200000)) /* |x| < 2**-29 */
{
math_force_eval (two54 + x); /* raise inexact */
if (ax < 0x3c900000) /* |x| < 2**-54 */
{
...
}
else
return x - x * x * 0.5;
FMA and non-FMA code sequences look similar. Non-FMA version is slightly
faster. Since log1p is called by asinh and atanh, it improves asinh
performance by:
Before After Improvement
max 75.645 63.135 16%
min 10.074 10.071 0%
mean 15.9483 14.9089 6%
and improves atanh performance by:
Before After Improvement
max 91.768 75.081 18%
min 15.548 13.883 10%
mean 18.3713 16.8011 8%
Diffstat (limited to 'sysdeps/x86_64/fpu')
| -rw-r--r-- | sysdeps/x86_64/fpu/multiarch/Makefile | 2 | ||||
| -rw-r--r-- | sysdeps/x86_64/fpu/multiarch/s_log1p-fma.c | 4 | ||||
| -rw-r--r-- | sysdeps/x86_64/fpu/multiarch/s_log1p.c | 29 |
3 files changed, 35 insertions, 0 deletions
diff --git a/sysdeps/x86_64/fpu/multiarch/Makefile b/sysdeps/x86_64/fpu/multiarch/Makefile index add339a876..ea81753b70 100644 --- a/sysdeps/x86_64/fpu/multiarch/Makefile +++ b/sysdeps/x86_64/fpu/multiarch/Makefile @@ -38,6 +38,7 @@ libm-sysdep_routines += \ e_pow-fma \ s_atan-fma \ s_expm1-fma \ + s_log1p-fma \ s_sin-fma \ s_sincos-fma \ s_tan-fma \ @@ -51,6 +52,7 @@ CFLAGS-e_log2-fma.c = -mfma -mavx2 CFLAGS-e_pow-fma.c = -mfma -mavx2 CFLAGS-s_atan-fma.c = -mfma -mavx2 CFLAGS-s_expm1-fma.c = -mfma -mavx2 +CFLAGS-s_log1p-fma.c = -mfma -mavx2 CFLAGS-s_sin-fma.c = -mfma -mavx2 CFLAGS-s_tan-fma.c = -mfma -mavx2 CFLAGS-s_sincos-fma.c = -mfma -mavx2 diff --git a/sysdeps/x86_64/fpu/multiarch/s_log1p-fma.c b/sysdeps/x86_64/fpu/multiarch/s_log1p-fma.c new file mode 100644 index 0000000000..8952df8f9e --- /dev/null +++ b/sysdeps/x86_64/fpu/multiarch/s_log1p-fma.c @@ -0,0 +1,4 @@ +#define __log1p __log1p_fma +#define SECTION __attribute__ ((section (".text.fma"))) + +#include <sysdeps/ieee754/dbl-64/s_log1p.c> diff --git a/sysdeps/x86_64/fpu/multiarch/s_log1p.c b/sysdeps/x86_64/fpu/multiarch/s_log1p.c new file mode 100644 index 0000000000..6ce5198d6d --- /dev/null +++ b/sysdeps/x86_64/fpu/multiarch/s_log1p.c @@ -0,0 +1,29 @@ +/* Multiple versions of log1p. + Copyright (C) 2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include <libm-alias-double.h> + +extern double __redirect_log1p (double); + +#define SYMBOL_NAME log1p +#include "ifunc-fma.h" + +libc_ifunc_redirected (__redirect_log1p, __log1p, IFUNC_SELECTOR ()); + +#define __log1p __log1p_sse2 +#include <sysdeps/ieee754/dbl-64/s_log1p.c> |