Re: [PATCH v2 11/18] Use GCC builtins for trunc functions if desired.

[Adhemerval Zanella <adhemerval dot zanella at linaro dot org>]

On 09/12/2019 09:46, Stefan Liebler wrote:
> This patch is using the corresponding GCC builtin for truncf, trunc,
> truncl and truncf128 if the USE_FUNCTION_BUILTIN macros are defined to one
> in math-use-builtins.h.
> 
> This is the case for s390 if build with at least --march=z196 --mzarch.
> Otherwise the generic implementation is used.  The code of the generic
> implementation is not changed.

LGTM, thanks.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

> ---
>  sysdeps/generic/math-use-builtins.h         |  5 +++++
>  sysdeps/ieee754/dbl-64/s_trunc.c            |  6 ++++++
>  sysdeps/ieee754/float128/float128_private.h |  3 +++
>  sysdeps/ieee754/flt-32/s_truncf.c           |  6 ++++++
>  sysdeps/ieee754/ldbl-128/s_truncl.c         |  6 ++++++
>  sysdeps/s390/fpu/math-use-builtins.h        | 11 +++++++++++
>  6 files changed, 37 insertions(+)
> 
> diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
> index 076ec661b0..ab379f45ba 100644
> --- a/sysdeps/generic/math-use-builtins.h
> +++ b/sysdeps/generic/math-use-builtins.h
> @@ -41,4 +41,9 @@
>  #define USE_CEILL_BUILTIN 0
>  #define USE_CEILF128_BUILTIN 0
>  
> +#define USE_TRUNC_BUILTIN 0
> +#define USE_TRUNCF_BUILTIN 0
> +#define USE_TRUNCL_BUILTIN 0
> +#define USE_TRUNCF128_BUILTIN 0
> +
>  #endif /* math-use-builtins.h */

OK.

> diff --git a/sysdeps/ieee754/dbl-64/s_trunc.c b/sysdeps/ieee754/dbl-64/s_trunc.c
> index 0de68ce298..c3129fea7b 100644
> --- a/sysdeps/ieee754/dbl-64/s_trunc.c
> +++ b/sysdeps/ieee754/dbl-64/s_trunc.c
> @@ -22,11 +22,16 @@
>  
>  #include <math_private.h>
>  #include <libm-alias-double.h>
> +#include <math-use-builtins.h>
>  
>  
>  double
>  __trunc (double x)
>  {
> +#if USE_TRUNC_BUILTIN
> +  return __builtin_trunc (x);
> +#else
> +  /* Use generic implementation.  */
>    int64_t i0, j0;
>    int64_t sx;
>  
> @@ -49,6 +54,7 @@ __trunc (double x)
>      }
>  
>    return x;
> +#endif /* ! USE_TRUNC_BUILTIN  */
>  }
>  #ifndef __trunc
>  libm_alias_double (__trunc, trunc)

Ok.

> diff --git a/sysdeps/ieee754/float128/float128_private.h b/sysdeps/ieee754/float128/float128_private.h
> index 01881b574a..9cd3a63f11 100644
> --- a/sysdeps/ieee754/float128/float128_private.h
> +++ b/sysdeps/ieee754/float128/float128_private.h
> @@ -148,6 +148,8 @@
>  #define USE_FLOORL_BUILTIN USE_FLOORF128_BUILTIN
>  #undef USE_CEILL_BUILTIN
>  #define USE_CEILL_BUILTIN USE_CEILF128_BUILTIN
> +#undef USE_TRUNCL_BUILTIN
> +#define USE_TRUNCL_BUILTIN USE_TRUNCF128_BUILTIN
>  
>  /* IEEE function renames.  */
>  #define __ieee754_acoshl __ieee754_acoshf128
> @@ -355,6 +357,7 @@
>  #define __builtin_rintl __builtin_rintf128
>  #define __builtin_floorl __builtin_floorf128
>  #define __builtin_ceill __builtin_ceilf128
> +#define __builtin_truncl __builtin_truncf128
>  
>  /* Get the constant suffix from bits/floatn-compat.h.  */
>  #define L(x) __f128 (x)

Ok.

> diff --git a/sysdeps/ieee754/flt-32/s_truncf.c b/sysdeps/ieee754/flt-32/s_truncf.c
> index e587706b5b..274638820e 100644
> --- a/sysdeps/ieee754/flt-32/s_truncf.c
> +++ b/sysdeps/ieee754/flt-32/s_truncf.c
> @@ -22,11 +22,16 @@
>  
>  #include <math_private.h>
>  #include <libm-alias-float.h>
> +#include <math-use-builtins.h>
>  
>  
>  float
>  __truncf (float x)
>  {
> +#if USE_TRUNCF_BUILTIN
> +  return __builtin_truncf (x);
> +#else
> +  /* Use generic implementation.  */
>    int32_t i0, j0;
>    int sx;
>  
> @@ -49,6 +54,7 @@ __truncf (float x)
>      }
>  
>    return x;
> +#endif /* ! USE_TRUNCF_BUILTIN  */
>  }
>  #ifndef __truncf
>  libm_alias_float (__trunc, trunc)

Ok.

> diff --git a/sysdeps/ieee754/ldbl-128/s_truncl.c b/sysdeps/ieee754/ldbl-128/s_truncl.c
> index de4dd34d59..d11ab937e2 100644
> --- a/sysdeps/ieee754/ldbl-128/s_truncl.c
> +++ b/sysdeps/ieee754/ldbl-128/s_truncl.c
> @@ -23,11 +23,16 @@
>  
>  #include <math_private.h>
>  #include <libm-alias-ldouble.h>
> +#include <math-use-builtins.h>
>  
>  
>  _Float128
>  __truncl (_Float128 x)
>  {
> +#if USE_TRUNCL_BUILTIN
> +  return __builtin_truncl (x);
> +#else
> +  /* Use generic implementation.  */
>    int32_t j0;
>    uint64_t i0, i1, sx;
>  
> @@ -54,5 +59,6 @@ __truncl (_Float128 x)
>      }
>  
>    return x;
> +#endif /* ! USE_TRUNCL_BUILTIN  */
>  }
>  libm_alias_ldouble (__trunc, trunc)

Ok.

> diff --git a/sysdeps/s390/fpu/math-use-builtins.h b/sysdeps/s390/fpu/math-use-builtins.h
> index 5435cbb65f..a39715c612 100644
> --- a/sysdeps/s390/fpu/math-use-builtins.h
> +++ b/sysdeps/s390/fpu/math-use-builtins.h
> @@ -42,16 +42,22 @@
>  # define USE_CEILF_BUILTIN 1
>  # define USE_CEILL_BUILTIN 1
>  
> +# define USE_TRUNC_BUILTIN 1
> +# define USE_TRUNCF_BUILTIN 1
> +# define USE_TRUNCL_BUILTIN 1
> +
>  # if __GNUC_PREREQ (8, 0)
>  #  define USE_NEARBYINTF128_BUILTIN 1
>  #  define USE_RINTF128_BUILTIN 1
>  #  define USE_FLOORF128_BUILTIN 1
>  #  define USE_CEILF128_BUILTIN 1
> +#  define USE_TRUNCF128_BUILTIN 1
>  # else
>  #  define USE_NEARBYINTF128_BUILTIN 0
>  #  define USE_RINTF128_BUILTIN 0
>  #  define USE_FLOORF128_BUILTIN 0
>  #  define USE_CEILF128_BUILTIN 0
> +#  define USE_TRUNCF128_BUILTIN 0
>  # endif
>  
>  #else
> @@ -77,6 +83,11 @@
>  # define USE_CEILL_BUILTIN 0
>  # define USE_CEILF128_BUILTIN 0
>  
> +# define USE_TRUNC_BUILTIN 0
> +# define USE_TRUNCF_BUILTIN 0
> +# define USE_TRUNCL_BUILTIN 0
> +# define USE_TRUNCF128_BUILTIN 0
> +
>  #endif /* ! HAVE_S390_MIN_Z196_ZARCH_ASM_SUPPORT  */
>  
>  #endif /* math-use-builtins.h */
> 

Ok.