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Re: [PATCH 04/10] i386: Replace assembly versions of e_exp2f with generic e_exp2f.c
On Thu, Oct 19, 2017 at 10:31 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> This patch replaces i386 assembly versions of e_exp2f with generic
> e_exp2f.c. For workload-spec2017.wrf, on Nehalem, it improves
> performance by:
>
> Before After Improvement
> reciprocal-throughput 112.996 40.0454 182%
> latency 126.581 54.4479 132%
>
> On Skylake, it improves performance by:
>
> Before After Improvement
> reciprocal-throughput 113.14 39.447 186%
> latency 136.068 55.684 144%
On IvyBridge with --disable-multi-arch, it improves performance by:
Before After Improvement
reciprocal-throughput 132.521 40.3759 228%
latency 145.791 58.4587 149%
> * sysdeps/i386/fpu/e_exp2f.S: Removed.
> * sysdeps/i386/fpu/w_exp2f.c: Likewise.
> * sysdeps/i386/fpu/libm-test-ulps: Updated for generic e_exp2f.c.
> * sysdeps/i386/i686/fpu/multiarch/libm-test-ulps: Likewise.
> * sysdeps/i386/i686/fpu/multiarch/Makefile (libm-sysdep_routines):
> Add e_exp2f-sse2.
> (CFLAGS-e_exp2f-sse2.c): New.
> * sysdeps/i386/i686/fpu/multiarch/e_exp2f-sse2.c: New file.
> * sysdeps/i386/i686/fpu/multiarch/e_exp2f.c: Likewise.
> ---
> sysdeps/i386/fpu/e_exp2f.S | 52 --------------------------
> sysdeps/i386/fpu/libm-test-ulps | 2 +
> sysdeps/i386/fpu/w_exp2f.c | 1 -
> sysdeps/i386/i686/fpu/multiarch/Makefile | 3 +-
> sysdeps/i386/i686/fpu/multiarch/e_exp2f-sse2.c | 3 ++
> sysdeps/i386/i686/fpu/multiarch/e_exp2f.c | 37 ++++++++++++++++++
> sysdeps/i386/i686/fpu/multiarch/libm-test-ulps | 2 +
> 7 files changed, 46 insertions(+), 54 deletions(-)
> delete mode 100644 sysdeps/i386/fpu/e_exp2f.S
> delete mode 100644 sysdeps/i386/fpu/w_exp2f.c
> create mode 100644 sysdeps/i386/i686/fpu/multiarch/e_exp2f-sse2.c
> create mode 100644 sysdeps/i386/i686/fpu/multiarch/e_exp2f.c
>
> diff --git a/sysdeps/i386/fpu/e_exp2f.S b/sysdeps/i386/fpu/e_exp2f.S
> deleted file mode 100644
> index 30623cd850..0000000000
> --- a/sysdeps/i386/fpu/e_exp2f.S
> +++ /dev/null
> @@ -1,52 +0,0 @@
> -/*
> - * Written by J.T. Conklin <jtc@netbsd.org>.
> - * Adapted for exp2 by Ulrich Drepper <drepper@cygnus.com>.
> - * Public domain.
> - */
> -
> -#include <machine/asm.h>
> -#include <i386-math-asm.h>
> -
> -DEFINE_FLT_MIN
> -
> -#ifdef PIC
> -# define MO(op) op##@GOTOFF(%ecx)
> -#else
> -# define MO(op) op
> -#endif
> -
> - .text
> -ENTRY(__ieee754_exp2f)
> -#ifdef PIC
> - LOAD_PIC_REG (cx)
> -#endif
> - flds 4(%esp)
> -/* I added the following ugly construct because exp(+-Inf) resulted
> - in NaN. The ugliness results from the bright minds at Intel.
> - For the i686 the code can be written better.
> - -- drepper@cygnus.com. */
> - fxam /* Is NaN or +-Inf? */
> - fstsw %ax
> - movb $0x45, %dh
> - andb %ah, %dh
> - cmpb $0x05, %dh
> - je 1f /* Is +-Inf, jump. */
> - fld %st
> - frndint /* int(x) */
> - fsubr %st,%st(1) /* fract(x) */
> - fxch
> - f2xm1 /* 2^(fract(x)) - 1 */
> - fld1
> - faddp /* 2^(fract(x)) */
> - fscale /* e^x */
> - fstp %st(1)
> - FLT_NARROW_EVAL_UFLOW_NONNEG_NAN
> - ret
> -
> -1: testl $0x200, %eax /* Test sign. */
> - jz 2f /* If positive, jump. */
> - fstp %st
> - fldz /* Set result to 0. */
> -2: ret
> -END (__ieee754_exp2f)
> -strong_alias (__ieee754_exp2f, __exp2f_finite)
> diff --git a/sysdeps/i386/fpu/libm-test-ulps b/sysdeps/i386/fpu/libm-test-ulps
> index 60a721c000..5a319f147b 100644
> --- a/sysdeps/i386/fpu/libm-test-ulps
> +++ b/sysdeps/i386/fpu/libm-test-ulps
> @@ -1921,7 +1921,9 @@ ildouble: 1
> ldouble: 1
>
> Function: "exp2_upward":
> +float: 1
> float128: 2
> +ifloat: 1
> ifloat128: 2
> ildouble: 1
> ldouble: 1
> diff --git a/sysdeps/i386/fpu/w_exp2f.c b/sysdeps/i386/fpu/w_exp2f.c
> deleted file mode 100644
> index 583065d12a..0000000000
> --- a/sysdeps/i386/fpu/w_exp2f.c
> +++ /dev/null
> @@ -1 +0,0 @@
> -#include <sysdeps/../math/w_exp2f.c>
> diff --git a/sysdeps/i386/i686/fpu/multiarch/Makefile b/sysdeps/i386/i686/fpu/multiarch/Makefile
> index c5e8cfd689..2723f570af 100644
> --- a/sysdeps/i386/i686/fpu/multiarch/Makefile
> +++ b/sysdeps/i386/i686/fpu/multiarch/Makefile
> @@ -1,6 +1,7 @@
> ifeq ($(subdir),math)
> -libm-sysdep_routines += e_expf-sse2 s_sinf-sse2 s_cosf-sse2 \
> +libm-sysdep_routines += e_exp2f-sse2 e_expf-sse2 s_sinf-sse2 s_cosf-sse2 \
> s_sincosf-sse2
>
> +CFLAGS-e_exp2f-sse2.c = -msse2 -mfpmath=sse
> CFLAGS-e_expf-sse2.c = -msse2 -mfpmath=sse
> endif
> diff --git a/sysdeps/i386/i686/fpu/multiarch/e_exp2f-sse2.c b/sysdeps/i386/i686/fpu/multiarch/e_exp2f-sse2.c
> new file mode 100644
> index 0000000000..dc3138dc24
> --- /dev/null
> +++ b/sysdeps/i386/i686/fpu/multiarch/e_exp2f-sse2.c
> @@ -0,0 +1,3 @@
> +#define __exp2f __exp2f_sse2
> +
> +#include <sysdeps/ieee754/flt-32/e_exp2f.c>
> diff --git a/sysdeps/i386/i686/fpu/multiarch/e_exp2f.c b/sysdeps/i386/i686/fpu/multiarch/e_exp2f.c
> new file mode 100644
> index 0000000000..0a5727f7de
> --- /dev/null
> +++ b/sysdeps/i386/i686/fpu/multiarch/e_exp2f.c
> @@ -0,0 +1,37 @@
> +/* Multiple versions of exp2f.
> + Copyright (C) 2017 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
> + <http://www.gnu.org/licenses/>. */
> +
> +extern float __redirect_exp2f (float);
> +
> +#define SYMBOL_NAME exp2f
> +#include "ifunc-sse2.h"
> +
> +libc_ifunc_redirected (__redirect_exp2f, __exp2f, IFUNC_SELECTOR ());
> +
> +#ifdef SHARED
> +# include <shlib-compat.h>
> +versioned_symbol (libm, __exp2f, exp2f, GLIBC_2_27);
> +#else
> +weak_alias (__exp2f, exp2f)
> +#endif
> +
> +strong_alias (__exp2f, __ieee754_exp2f)
> +strong_alias (__exp2f, __exp2f_finite)
> +
> +#define __exp2f __exp2f_ia32
> +#include <sysdeps/ieee754/flt-32/e_exp2f.c>
> diff --git a/sysdeps/i386/i686/fpu/multiarch/libm-test-ulps b/sysdeps/i386/i686/fpu/multiarch/libm-test-ulps
> index 5ff641f848..2d056a9260 100644
> --- a/sysdeps/i386/i686/fpu/multiarch/libm-test-ulps
> +++ b/sysdeps/i386/i686/fpu/multiarch/libm-test-ulps
> @@ -1921,7 +1921,9 @@ ildouble: 1
> ldouble: 1
>
> Function: "exp2_upward":
> +float: 1
> float128: 2
> +ifloat: 1
> ifloat128: 2
> ildouble: 1
> ldouble: 1
> --
> 2.13.6
>
--
H.J.