Re: [PATCH v2 03/10] i386: Use generic fmod

["H.J. Lu" <hjl.tools@gmail.com>]

On Wed, Mar 27, 2024 at 12:40 PM Adhemerval Zanella
<adhemerval.zanella@linaro.org> wrote:
>
> The benchtest results shows a slight improvement (Ryzen 5900, gcc
> 13.2.1):
>
> * sysdeps/i386/fpu/e_fmod.S:
>   "fmod": {
>    "subnormals": {
>     "duration": 3.68855e+09,
>     "iterations": 2.12608e+08,
>     "max": 62.012,
>     "min": 16.798,
>     "mean": 17.349
>    },
>    "normal": {
>     "duration": 3.88459e+09,
>     "iterations": 7.168e+06,
>     "max": 2879.12,
>     "min": 16.909,
>     "mean": 541.934
>    },
>    "close-exponents": {
>     "duration": 3.692e+09,
>     "iterations": 1.96608e+08,
>     "max": 66.452,
>     "min": 16.835,
>     "mean": 18.7785
>    }
>   }
>
> * generic
>   "fmod": {
>    "subnormals": {
>     "duration": 3.68645e+09,
>     "iterations": 2.2848e+08,
>     "max": 66.896,
>     "min": 15.91,
>     "mean": 16.1347
>    },
>    "normal": {
>     "duration": 4.1455e+09,
>     "iterations": 8.192e+06,
>     "max": 3376.18,
>     "min": 15.873,
>     "mean": 506.043
>    },
>    "close-exponents": {
>     "duration": 3.70197e+09,
>     "iterations": 2.08896e+08,
>     "max": 69.597,
>     "min": 15.947,
>     "mean": 17.7216
>    }
>   }
> ---
>  sysdeps/i386/fpu/Versions                 |  4 ++++
>  sysdeps/i386/fpu/e_fmod.S                 | 18 ------------------
>  sysdeps/i386/fpu/e_fmod.c                 |  2 ++
>  sysdeps/i386/fpu/math_err.c               |  1 -
>  sysdeps/i386/fpu/w_fmod_compat.c          | 15 ---------------
>  sysdeps/ieee754/dbl-64/e_fmod.c           |  5 ++++-
>  sysdeps/mach/hurd/i386/libm.abilist       |  1 +
>  sysdeps/unix/sysv/linux/i386/libm.abilist |  1 +
>  8 files changed, 12 insertions(+), 35 deletions(-)
>  delete mode 100644 sysdeps/i386/fpu/e_fmod.S
>  create mode 100644 sysdeps/i386/fpu/e_fmod.c
>  delete mode 100644 sysdeps/i386/fpu/math_err.c
>  delete mode 100644 sysdeps/i386/fpu/w_fmod_compat.c
>
> diff --git a/sysdeps/i386/fpu/Versions b/sysdeps/i386/fpu/Versions
> index a2eec371f1..d37bc1eae6 100644
> --- a/sysdeps/i386/fpu/Versions
> +++ b/sysdeps/i386/fpu/Versions
> @@ -3,4 +3,8 @@ libm {
>      # functions used in inline functions or macros
>      __expl; __expm1l;
>    }
> +  GLIBC_2.40 {
> +    # No SVID compatible error handling.
> +    fmod;
> +  }

This changes the ABI.  I assume that it fixes a real bug.   Is there a bug
report open for this?

>  }
> diff --git a/sysdeps/i386/fpu/e_fmod.S b/sysdeps/i386/fpu/e_fmod.S
> deleted file mode 100644
> index 86ac1bcfaf..0000000000
> --- a/sysdeps/i386/fpu/e_fmod.S
> +++ /dev/null
> @@ -1,18 +0,0 @@
> -/*
> - * Public domain.
> - */
> -
> -#include <machine/asm.h>
> -#include <libm-alias-finite.h>
> -
> -ENTRY(__ieee754_fmod)
> -       fldl    12(%esp)
> -       fldl    4(%esp)
> -1:     fprem
> -       fstsw   %ax
> -       sahf
> -       jp      1b
> -       fstp    %st(1)
> -       ret
> -END (__ieee754_fmod)
> -libm_alias_finite (__ieee754_fmod, __fmod)
> diff --git a/sysdeps/i386/fpu/e_fmod.c b/sysdeps/i386/fpu/e_fmod.c
> new file mode 100644
> index 0000000000..3625758f97
> --- /dev/null
> +++ b/sysdeps/i386/fpu/e_fmod.c
> @@ -0,0 +1,2 @@
> +#define FMOD_VERSION GLIBC_2_40
> +#include <sysdeps/ieee754/dbl-64/e_fmod.c>
> diff --git a/sysdeps/i386/fpu/math_err.c b/sysdeps/i386/fpu/math_err.c
> deleted file mode 100644
> index 1cc8931700..0000000000
> --- a/sysdeps/i386/fpu/math_err.c
> +++ /dev/null
> @@ -1 +0,0 @@
> -/* Not needed.  */
> diff --git a/sysdeps/i386/fpu/w_fmod_compat.c b/sysdeps/i386/fpu/w_fmod_compat.c
> deleted file mode 100644
> index 528bfc2a13..0000000000
> --- a/sysdeps/i386/fpu/w_fmod_compat.c
> +++ /dev/null
> @@ -1,15 +0,0 @@
> -/* i386 provides an optimized __ieee752_fmod.  */
> -#include <math-svid-compat.h>
> -#ifdef SHARED
> -# undef SHLIB_COMPAT
> -# define SHLIB_COMPAT(a, b, c) 1
> -# undef LIBM_SVID_COMPAT
> -# define LIBM_SVID_COMPAT 1
> -# undef compat_symbol
> -# define compat_symbol(a, b, c, d)
> -# include <math/w_fmod_compat.c>
> -libm_alias_double (__fmod_compat, fmod)
> -#else
> -#include <math-type-macros-double.h>
> -#include <w_fmod_template.c>
> -#endif
> diff --git a/sysdeps/ieee754/dbl-64/e_fmod.c b/sysdeps/ieee754/dbl-64/e_fmod.c
> index b33cfb1223..7651cd212a 100644
> --- a/sysdeps/ieee754/dbl-64/e_fmod.c
> +++ b/sysdeps/ieee754/dbl-64/e_fmod.c
> @@ -175,7 +175,10 @@ __fmod (double x, double y)
>  strong_alias (__fmod, __ieee754_fmod)
>  libm_alias_finite (__ieee754_fmod, __fmod)
>  #if LIBM_SVID_COMPAT
> -versioned_symbol (libm, __fmod, fmod, GLIBC_2_38);
> +# ifndef FMOD_VERSION
> +#  define FMOD_VERSION GLIBC_2_38
> +# endif
> +versioned_symbol (libm, __fmod, fmod, FMOD_VERSION);
>  libm_alias_double_other (__fmod, fmod)
>  #else
>  libm_alias_double (__fmod, fmod)
> diff --git a/sysdeps/mach/hurd/i386/libm.abilist b/sysdeps/mach/hurd/i386/libm.abilist
> index 8f40ddb150..30665f8b1a 100644
> --- a/sysdeps/mach/hurd/i386/libm.abilist
> +++ b/sysdeps/mach/hurd/i386/libm.abilist
> @@ -1181,3 +1181,4 @@ GLIBC_2.35 fsqrt F
>  GLIBC_2.35 fsqrtl F
>  GLIBC_2.35 hypot F
>  GLIBC_2.35 hypotf F
> +GLIBC_2.40 fmod F
> diff --git a/sysdeps/unix/sysv/linux/i386/libm.abilist b/sysdeps/unix/sysv/linux/i386/libm.abilist
> index 5d89aaa08e..44932f111d 100644
> --- a/sysdeps/unix/sysv/linux/i386/libm.abilist
> +++ b/sysdeps/unix/sysv/linux/i386/libm.abilist
> @@ -1188,3 +1188,4 @@ GLIBC_2.35 fsqrt F
>  GLIBC_2.35 fsqrtl F
>  GLIBC_2.35 hypot F
>  GLIBC_2.35 hypotf F
> +GLIBC_2.40 fmod F
> --
> 2.34.1
>


-- 
H.J.