[PATCH] x86_64: Add asinh with FMA

[Sunil Pandey]

On Thu, Mar 13, 2025 at 6:04 PM H.J. Lu <hjl.tools@gmail.com> wrote:

> On Thu, Mar 13, 2025 at 5:27 PM Sunil K Pandey <skpgkp2@gmail.com> wrote:
> >
> > FMA and non-FMA performance are similar on SPR.
> >
> >                         Before          After           Improvement
> > reciprocal-throughput   12.226          12.4064         -1%
> > latency                 49.4701         48.4424         2%
>
> Since there is no real advantage for FMA, it isn't necessary.
>
>
This request comes from https://issues.redhat.com/browse/RHEL-1063
We don't see any real advantage because in upstream glibc underlying
function call

__ieee754_log
__log1p

are already FMA enabled and invoked via ifunc.

FMA version could be beneficial if the underlying function is replaced
by direct call.



> > ---
> >  benchtests/asinh-inputs                    |  1 +
> >  sysdeps/ieee754/dbl-64/s_asinh.c           |  5 ++++
> >  sysdeps/x86_64/fpu/multiarch/Makefile      |  2 ++
> >  sysdeps/x86_64/fpu/multiarch/s_asinh-fma.c |  7 +++++
> >  sysdeps/x86_64/fpu/multiarch/s_asinh.c     | 31 ++++++++++++++++++++++
> >  5 files changed, 46 insertions(+)
> >  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_asinh-fma.c
> >  create mode 100644 sysdeps/x86_64/fpu/multiarch/s_asinh.c
> >
> > diff --git a/benchtests/asinh-inputs b/benchtests/asinh-inputs
> > index 8dfa37c49f..946e7b4d22 100644
> > --- a/benchtests/asinh-inputs
> > +++ b/benchtests/asinh-inputs
> > @@ -1,6 +1,7 @@
> >  ## args: double
> >  ## ret: double
> >  ## includes: math.h
> > +## name: workload-random
> >  0x1.408fb643484cep-11
> >  0x1.f0763423f1d52p-23
> >  -0x1.681573418e494p4
> > diff --git a/sysdeps/ieee754/dbl-64/s_asinh.c
> b/sysdeps/ieee754/dbl-64/s_asinh.c
> > index 7fd281d791..04b686a28e 100644
> > --- a/sysdeps/ieee754/dbl-64/s_asinh.c
> > +++ b/sysdeps/ieee754/dbl-64/s_asinh.c
> > @@ -32,6 +32,11 @@ static const double
> >    ln2 = 6.93147180559945286227e-01, /* 0x3FE62E42, 0xFEFA39EF */
> >    huge = 1.00000000000000000000e+300;
> >
> > +#ifndef SECTION
> > +# define SECTION
> > +#endif
> > +
> > +SECTION
> >  double
> >  __asinh (double x)
> >  {
> > diff --git a/sysdeps/x86_64/fpu/multiarch/Makefile
> b/sysdeps/x86_64/fpu/multiarch/Makefile
> > index 3403422443..1ab46bb446 100644
> > --- a/sysdeps/x86_64/fpu/multiarch/Makefile
> > +++ b/sysdeps/x86_64/fpu/multiarch/Makefile
> > @@ -7,6 +7,7 @@ CFLAGS-e_log-fma.c = -mfma -mavx2
> >  CFLAGS-e_log2-fma.c = -mfma -mavx2
> >  CFLAGS-e_pow-fma.c = -mfma -mavx2
> >  CFLAGS-e_sinh-fma.c = -mfma -mavx2
> > +CFLAGS-s_asinh-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
> > @@ -73,6 +74,7 @@ libm-sysdep_routines += \
> >    e_pow-fma \
> >    e_powf-fma \
> >    e_sinh-fma \
> > +  s_asinh-fma \
> >    s_atan-avx \
> >    s_atan-fma \
> >    s_ceil-sse4_1 \
> > diff --git a/sysdeps/x86_64/fpu/multiarch/s_asinh-fma.c
> b/sysdeps/x86_64/fpu/multiarch/s_asinh-fma.c
> > new file mode 100644
> > index 0000000000..293a255005
> > --- /dev/null
> > +++ b/sysdeps/x86_64/fpu/multiarch/s_asinh-fma.c
> > @@ -0,0 +1,7 @@
> > +#define __asinh __asinh_fma
> > +#define __ieee754_log __ieee754_log_fma
> > +#define __log1p __log1p_fma
> > +
> > +#define SECTION __attribute__ ((section (".text.fma")))
> > +
> > +#include <sysdeps/ieee754/dbl-64/s_asinh.c>
> > diff --git a/sysdeps/x86_64/fpu/multiarch/s_asinh.c
> b/sysdeps/x86_64/fpu/multiarch/s_asinh.c
> > new file mode 100644
> > index 0000000000..509d74c96b
> > --- /dev/null
> > +++ b/sysdeps/x86_64/fpu/multiarch/s_asinh.c
> > @@ -0,0 +1,31 @@
> > +/* Multiple versions of asinh.
> > +   Copyright (C) 2025 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 <sysdeps/x86/isa-level.h>
> > +#if MINIMUM_X86_ISA_LEVEL < AVX2_X86_ISA_LEVEL
> > +
> > +extern double __redirect_asinh (double);
> > +
> > +# define SYMBOL_NAME asinh
> > +# include "ifunc-fma.h"
> > +
> > +libc_ifunc_redirected (__redirect_asinh, __asinh, IFUNC_SELECTOR ());
> > +
> > +# define __asinh __asinh_sse2
> > +#endif
> > +#include <sysdeps/ieee754/dbl-64/s_asinh.c>
> > --
> > 2.48.1
> >
>
>
> --
> H.J.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://sourceware.org/pipermail/libc-alpha/attachments/20250313/eb549220/attachment-0001.htm>