[PATCH v6 3/3] Use GCC builtins for roundeven functions if desired.
H.J. Lu
hjl.tools@gmail.com
Sun May 23 19:03:51 GMT 2021
On Fri, May 21, 2021 at 5:23 PM Shen-Ta Hsieh <ibmibmibm.tw@gmail.com> wrote:
>
> This patch is using the corresponding GCC builtin for roundevenf,
> roundeven and roundevenl if the USE_FUNCTION_BUILTIN macros are defined
> to one in math-use-builtins.h.
>
> These builtin functions is supported since GCC 10.
>
> The code of the generic implementation is not changed.
>
> Signed-off-by: Shen-Ta Hsieh <ibmibmibm.tw@gmail.com>
> ---
> sysdeps/generic/math-use-builtins-roundeven.h | 4 ++++
> sysdeps/generic/math-use-builtins.h | 1 +
> sysdeps/ieee754/dbl-64/s_roundeven.c | 5 +++++
> sysdeps/ieee754/flt-32/s_roundevenf.c | 5 +++++
> sysdeps/ieee754/ldbl-128/s_roundevenl.c | 5 +++++
> 5 files changed, 20 insertions(+)
> create mode 100644 sysdeps/generic/math-use-builtins-roundeven.h
>
> diff --git a/sysdeps/generic/math-use-builtins-roundeven.h b/sysdeps/generic/math-use-builtins-roundeven.h
> new file mode 100644
> index 0000000000..bd2e84c93f
> --- /dev/null
> +++ b/sysdeps/generic/math-use-builtins-roundeven.h
> @@ -0,0 +1,4 @@
> +#define USE_ROUNDEVEN_BUILTIN 0
> +#define USE_ROUNDEVENF_BUILTIN 0
> +#define USE_ROUNDEVENL_BUILTIN 0
> +#define USE_ROUNDEVENF128_BUILTIN 0
> diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
> index cc3e9f2201..19d2d1cf3c 100644
> --- a/sysdeps/generic/math-use-builtins.h
> +++ b/sysdeps/generic/math-use-builtins.h
> @@ -30,6 +30,7 @@
> #include <math-use-builtins-ceil.h>
> #include <math-use-builtins-trunc.h>
> #include <math-use-builtins-round.h>
> +#include <math-use-builtins-roundeven.h>
> #include <math-use-builtins-copysign.h>
> #include <math-use-builtins-sqrt.h>
> #include <math-use-builtins-fma.h>
> diff --git a/sysdeps/ieee754/dbl-64/s_roundeven.c b/sysdeps/ieee754/dbl-64/s_roundeven.c
> index 5deff3bb8a..88c051e9fe 100644
> --- a/sysdeps/ieee754/dbl-64/s_roundeven.c
> +++ b/sysdeps/ieee754/dbl-64/s_roundeven.c
> @@ -21,6 +21,7 @@
> #include <math_private.h>
> #include <libm-alias-double.h>
> #include <stdint.h>
> +#include <math-use-builtins.h>
>
> #define BIAS 0x3ff
> #define MANT_DIG 53
> @@ -29,6 +30,9 @@
> double
> __roundeven (double x)
> {
> +#if USE_ROUNDEVEN_BUILTIN
> + return __builtin_roundeven (x);
> +#else
> uint64_t ix, ux;
> EXTRACT_WORDS64 (ix, x);
> ux = ix & 0x7fffffffffffffffULL;
> @@ -66,6 +70,7 @@ __roundeven (double x)
> ix &= 0x8000000000000000ULL;
> INSERT_WORDS64 (x, ix);
> return x;
> +#endif /* ! USE_ROUNDEVEN_BUILTIN */
> }
> #ifndef __roundeven
> libm_alias_double (__roundeven, roundeven)
> diff --git a/sysdeps/ieee754/flt-32/s_roundevenf.c b/sysdeps/ieee754/flt-32/s_roundevenf.c
> index 2cc0d7b001..4f568579d8 100644
> --- a/sysdeps/ieee754/flt-32/s_roundevenf.c
> +++ b/sysdeps/ieee754/flt-32/s_roundevenf.c
> @@ -21,6 +21,7 @@
> #include <math.h>
> #include <math_private.h>
> #include <libm-alias-float.h>
> +#include <math-use-builtins.h>
> #include <stdint.h>
>
> #define BIAS 0x7f
> @@ -30,6 +31,9 @@
> float
> __roundevenf (float x)
> {
> +#if USE_ROUNDEVENF_BUILTIN
> + return __builtin_roundevenf (x);
> +#else
> uint32_t ix, ux;
> GET_FLOAT_WORD (ix, x);
> ux = ix & 0x7fffffff;
> @@ -67,6 +71,7 @@ __roundevenf (float x)
> ix &= 0x80000000;
> SET_FLOAT_WORD (x, ix);
> return x;
> +#endif /* ! USE_ROUNDEVENF_BUILTIN */
> }
> #ifndef __roundevenf
> libm_alias_float (__roundeven, roundeven)
> diff --git a/sysdeps/ieee754/ldbl-128/s_roundevenl.c b/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> index 7c9c11fad2..afbf13d4f2 100644
> --- a/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> +++ b/sysdeps/ieee754/ldbl-128/s_roundevenl.c
> @@ -21,6 +21,7 @@
> #include <math.h>
> #include <math_private.h>
> #include <libm-alias-ldouble.h>
> +#include <math-use-builtins.h>
> #include <stdint.h>
>
> #define BIAS 0x3fff
> @@ -30,6 +31,9 @@
> _Float128
> __roundevenl (_Float128 x)
> {
> +#if USE_ROUNDEVENL_BUILTIN
> + return __builtin_roundevenl (x);
> +#else
> uint64_t hx, lx, uhx;
> GET_LDOUBLE_WORDS64 (hx, lx, x);
> uhx = hx & 0x7fffffffffffffffULL;
> @@ -101,5 +105,6 @@ __roundevenl (_Float128 x)
> }
> SET_LDOUBLE_WORDS64 (x, hx, lx);
> return x;
> +#endif /* ! USE_ROUNDEVENL_BUILTIN */
> }
> libm_alias_ldouble (__roundeven, roundeven)
> --
> 2.31.1
>
Do you need to map USE_ROUNDEVENL_BUILTIN to
USE_ROUNDEVENF128_BUILTIN in float128_private.h?
--
H.J.
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