[v2,2/4] iee754: provide gcc builtins based generic fma functions
Commit Message
---
sysdeps/generic/math-use-builtins.h | 5 +++++
sysdeps/ieee754/dbl-64/s_fma.c | 6 ++++++
sysdeps/ieee754/dbl-64/s_fmaf.c | 6 ++++++
sysdeps/ieee754/float128/float128_private.h | 2 ++
sysdeps/ieee754/ldbl-128/s_fmal.c | 5 +++++
5 files changed, 24 insertions(+)
Comments
On 6/2/20 2:35 AM, Vineet Gupta via Libc-alpha wrote:
> ---
> sysdeps/generic/math-use-builtins.h | 5 +++++
> sysdeps/ieee754/dbl-64/s_fma.c | 6 ++++++
> sysdeps/ieee754/dbl-64/s_fmaf.c | 6 ++++++
> sysdeps/ieee754/float128/float128_private.h | 2 ++
> sysdeps/ieee754/ldbl-128/s_fmal.c | 5 +++++
> 5 files changed, 24 insertions(+)
>
> diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
> index fc724c824a17..cf25ed8a2138 100644
> --- a/sysdeps/generic/math-use-builtins.h
> +++ b/sysdeps/generic/math-use-builtins.h
> @@ -63,4 +63,9 @@
> #define USE_SQRT_BUILTIN 0
> #define USE_SQRTF_BUILTIN 0
>
> +#define USE_FMA_BUILTIN 0
> +#define USE_FMAF_BUILTIN 0
> +#define USE_FMAL_BUILTIN 0
> +#define USE_FMAF128_BUILTIN 0
> +
> #endif /* math-use-builtins.h */
Please also update the current architecture specific math-use-builtins.h
file: sysdeps/s390/fpu/math-use-builtins.h
Otherwise it will break build on s390x.
> diff --git a/sysdeps/ieee754/dbl-64/s_fma.c b/sysdeps/ieee754/dbl-64/s_fma.c
> index 876df6e78bdc..9dc5b132b9ee 100644
> --- a/sysdeps/ieee754/dbl-64/s_fma.c
> +++ b/sysdeps/ieee754/dbl-64/s_fma.c
> @@ -25,6 +25,7 @@
> #include <fenv_private.h>
> #include <libm-alias-double.h>
> #include <tininess.h>
> +#include <math-use-builtins.h>
>
> /* This implementation uses rounding to odd to avoid problems with
> double rounding. See a paper by Boldo and Melquiond:
> @@ -33,6 +34,10 @@
> double
> __fma (double x, double y, double z)
> {
> +#if USE_FMA_BUILTIN
> + return __builtin_fma (x, y, z);
Architectures which have support for ldbl-128 will use the file
sysdeps/ieee754/ldbl-128/s_fma.c instead of
sysdeps/ieee754/dbl-64/s_fma.c. Should this file also be adjusted in
order to use the builtin if USE_FMA_BUILTIN is set to one?
> +#else
> + /* Use generic implementation. */
> union ieee754_double u, v, w;
> int adjust = 0;
> u.d = x;
> @@ -292,6 +297,7 @@ __fma (double x, double y, double z)
> v.ieee.mantissa1 |= j;
> return v.d * 0x1p-108;
> }
> +#endif /* ! USE_FMA_BUILTIN */
> }
> #ifndef __fma
> libm_alias_double (__fma, fma)
> diff --git a/sysdeps/ieee754/dbl-64/s_fmaf.c b/sysdeps/ieee754/dbl-64/s_fmaf.c
> index 57329d0a87fe..93b8660d5242 100644
> --- a/sysdeps/ieee754/dbl-64/s_fmaf.c
> +++ b/sysdeps/ieee754/dbl-64/s_fmaf.c
> @@ -23,6 +23,7 @@
> #include <math-barriers.h>
> #include <fenv_private.h>
> #include <libm-alias-float.h>
> +#include <math-use-builtins.h>
>
> /* This implementation relies on double being more than twice as
> precise as float and uses rounding to odd in order to avoid problems
> @@ -33,6 +34,10 @@
> float
> __fmaf (float x, float y, float z)
> {
> +#if USE_FMAF_BUILTIN
> + return __builtin_fmaf (x, y, z);
> +#else
> + /* Use generic implementation. */
> fenv_t env;
>
> /* Multiplication is always exact. */
> @@ -60,6 +65,7 @@ __fmaf (float x, float y, float z)
>
> /* And finally truncation with round to nearest. */
> return (float) u.d;
> +#endif /* ! USE_FMAF_BUILTIN */
> }
> #ifndef __fmaf
> libm_alias_float (__fma, fma)
> diff --git a/sysdeps/ieee754/float128/float128_private.h b/sysdeps/ieee754/float128/float128_private.h
> index f97463d9dc1b..ab6fc9f3c9cf 100644
> --- a/sysdeps/ieee754/float128/float128_private.h
> +++ b/sysdeps/ieee754/float128/float128_private.h
> @@ -154,6 +154,8 @@
> #define USE_ROUNDL_BUILTIN USE_ROUNDF128_BUILTIN
> #undef USE_COPYSIGNL_BUILTIN
> #define USE_COPYSIGNL_BUILTIN USE_COPYSIGNF128_BUILTIN
> +#undef USE_FMAL_BUILTIN
> +#define USE_FMAL_BUILTIN USE_FMAF128_BUILTIN
>
> /* IEEE function renames. */
> #define __ieee754_acoshl __ieee754_acoshf128
> diff --git a/sysdeps/ieee754/ldbl-128/s_fmal.c b/sysdeps/ieee754/ldbl-128/s_fmal.c
> index 7475015bcec6..a610499e47c7 100644
> --- a/sysdeps/ieee754/ldbl-128/s_fmal.c
> +++ b/sysdeps/ieee754/ldbl-128/s_fmal.c
> @@ -25,6 +25,7 @@
> #include <math_private.h>
> #include <libm-alias-ldouble.h>
> #include <tininess.h>
> +#include <math-use-builtins.h>
>
> /* This implementation uses rounding to odd to avoid problems with
> double rounding. See a paper by Boldo and Melquiond:
> @@ -33,6 +34,9 @@
> _Float128
> __fmal (_Float128 x, _Float128 y, _Float128 z)
> {
> +#if USE_FMAL_BUILTIN
> + return __builtin_fmal (x, y, z);
> +#else
> union ieee854_long_double u, v, w;
> int adjust = 0;
> u.d = x;
> @@ -296,5 +300,6 @@ __fmal (_Float128 x, _Float128 y, _Float128 z)
> v.ieee.mantissa3 |= j;
> return v.d * L(0x1p-228);
> }
> +#endif /* ! USE_FMAL_BUILTIN */
> }
> libm_alias_ldouble (__fma, fma)
>
On 6/2/20 5:51 AM, Stefan Liebler via Libc-alpha wrote:
> #endif /* math-use-builtins.h */
> Please also update the current architecture specific math-use-builtins.h
> file: sysdeps/s390/fpu/math-use-builtins.h
> Otherwise it will break build on s390x.
Done.
>> diff --git a/sysdeps/ieee754/dbl-64/s_fma.c b/sysdeps/ieee754/dbl-64/s_fma.c
>> index 876df6e78bdc..9dc5b132b9ee 100644
>> --- a/sysdeps/ieee754/dbl-64/s_fma.c
>> +++ b/sysdeps/ieee754/dbl-64/s_fma.c
>> @@ -25,6 +25,7 @@
>> #include <fenv_private.h>
>> #include <libm-alias-double.h>
>> #include <tininess.h>
>> +#include <math-use-builtins.h>
>>
>> /* This implementation uses rounding to odd to avoid problems with
>> double rounding. See a paper by Boldo and Melquiond:
>> @@ -33,6 +34,10 @@
>> double
>> __fma (double x, double y, double z)
>> {
>> +#if USE_FMA_BUILTIN
>> + return __builtin_fma (x, y, z);
>
> Architectures which have support for ldbl-128 will use the file
> sysdeps/ieee754/ldbl-128/s_fma.c instead of
> sysdeps/ieee754/dbl-64/s_fma.c. Should this file also be adjusted in
> order to use the builtin if USE_FMA_BUILTIN is set to one?
Right.
I used commit f82996f815 "Use GCC builtins for round functions if desired" as
starting point for my change. And seems it was not an ideal reference :-) as round
has far fewer instances than fma. Indeed fma is present in ldbl-128 and dbl-64 so
needs updating in both.
But just to be sure s390 is currently not using the newly introduced builtins so
I'll keep them as follows.
#define USE_SQRT_BUILTIN 0
#define USE_SQRTF_BUILTIN 0
#define USE_FMA_BUILTIN 0
#define USE_FMAF_BUILTIN 0
#define USE_FMAL_BUILTIN 0
#define USE_FMAF128_BUILTIN 0
-Vineet
On 02/06/2020 14:13, Vineet Gupta via Libc-alpha wrote:
> On 6/2/20 5:51 AM, Stefan Liebler via Libc-alpha wrote:
>> #endif /* math-use-builtins.h */
>> Please also update the current architecture specific math-use-builtins.h
>> file: sysdeps/s390/fpu/math-use-builtins.h
>> Otherwise it will break build on s390x.
>
> Done.
>
>>> diff --git a/sysdeps/ieee754/dbl-64/s_fma.c b/sysdeps/ieee754/dbl-64/s_fma.c
>>> index 876df6e78bdc..9dc5b132b9ee 100644
>>> --- a/sysdeps/ieee754/dbl-64/s_fma.c
>>> +++ b/sysdeps/ieee754/dbl-64/s_fma.c
>>> @@ -25,6 +25,7 @@
>>> #include <fenv_private.h>
>>> #include <libm-alias-double.h>
>>> #include <tininess.h>
>>> +#include <math-use-builtins.h>
>>>
>>> /* This implementation uses rounding to odd to avoid problems with
>>> double rounding. See a paper by Boldo and Melquiond:
>>> @@ -33,6 +34,10 @@
>>> double
>>> __fma (double x, double y, double z)
>>> {
>>> +#if USE_FMA_BUILTIN
>>> + return __builtin_fma (x, y, z);
>>
>> Architectures which have support for ldbl-128 will use the file
>> sysdeps/ieee754/ldbl-128/s_fma.c instead of
>> sysdeps/ieee754/dbl-64/s_fma.c. Should this file also be adjusted in
>> order to use the builtin if USE_FMA_BUILTIN is set to one?
>
> Right.
>
> I used commit f82996f815 "Use GCC builtins for round functions if desired" as
> starting point for my change. And seems it was not an ideal reference :-) as round
> has far fewer instances than fma. Indeed fma is present in ldbl-128 and dbl-64 so
> needs updating in both.
I think after this set is upstream I will refactor to make each symbol and its
variant (i.g sqrt, sqrtf, etc.) to be define on its own file. The default
math-use-builtins will then include each file:
/* math-use-builtins.h */
#inclde <math-use-builtins-sqrt.h>
[...]
With default USE_* begin 0. This would allow to add new builtin usage without
require to sync with every architecture (and without breaking its build as well).
>
> But just to be sure s390 is currently not using the newly introduced builtins so
> I'll keep them as follows.
>
> #define USE_SQRT_BUILTIN 0
> #define USE_SQRTF_BUILTIN 0
>
> #define USE_FMA_BUILTIN 0
> #define USE_FMAF_BUILTIN 0
> #define USE_FMAL_BUILTIN 0
> #define USE_FMAF128_BUILTIN 0
>
> -Vineet
It is ok, we can optimize s390 in a subsequent patch (since it does provide fma
and sqrtf builtins).
On 01/06/2020 21:35, Vineet Gupta wrote:
> ---
> sysdeps/generic/math-use-builtins.h | 5 +++++
> sysdeps/ieee754/dbl-64/s_fma.c | 6 ++++++
> sysdeps/ieee754/dbl-64/s_fmaf.c | 6 ++++++
> sysdeps/ieee754/float128/float128_private.h | 2 ++
> sysdeps/ieee754/ldbl-128/s_fmal.c | 5 +++++
> 5 files changed, 24 insertions(+)
LGTM with s390 fix pointed by Stefan.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
>
> diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
> index fc724c824a17..cf25ed8a2138 100644
> --- a/sysdeps/generic/math-use-builtins.h
> +++ b/sysdeps/generic/math-use-builtins.h
> @@ -63,4 +63,9 @@
> #define USE_SQRT_BUILTIN 0
> #define USE_SQRTF_BUILTIN 0
>
> +#define USE_FMA_BUILTIN 0
> +#define USE_FMAF_BUILTIN 0
> +#define USE_FMAL_BUILTIN 0
> +#define USE_FMAF128_BUILTIN 0
> +
> #endif /* math-use-builtins.h */
> diff --git a/sysdeps/ieee754/dbl-64/s_fma.c b/sysdeps/ieee754/dbl-64/s_fma.c
> index 876df6e78bdc..9dc5b132b9ee 100644
> --- a/sysdeps/ieee754/dbl-64/s_fma.c
> +++ b/sysdeps/ieee754/dbl-64/s_fma.c
> @@ -25,6 +25,7 @@
> #include <fenv_private.h>
> #include <libm-alias-double.h>
> #include <tininess.h>
> +#include <math-use-builtins.h>
>
> /* This implementation uses rounding to odd to avoid problems with
> double rounding. See a paper by Boldo and Melquiond:
> @@ -33,6 +34,10 @@
> double
> __fma (double x, double y, double z)
> {
> +#if USE_FMA_BUILTIN
> + return __builtin_fma (x, y, z);
> +#else
> + /* Use generic implementation. */
> union ieee754_double u, v, w;
> int adjust = 0;
> u.d = x;
> @@ -292,6 +297,7 @@ __fma (double x, double y, double z)
> v.ieee.mantissa1 |= j;
> return v.d * 0x1p-108;
> }
> +#endif /* ! USE_FMA_BUILTIN */
> }
> #ifndef __fma
> libm_alias_double (__fma, fma)
> diff --git a/sysdeps/ieee754/dbl-64/s_fmaf.c b/sysdeps/ieee754/dbl-64/s_fmaf.c
> index 57329d0a87fe..93b8660d5242 100644
> --- a/sysdeps/ieee754/dbl-64/s_fmaf.c
> +++ b/sysdeps/ieee754/dbl-64/s_fmaf.c
> @@ -23,6 +23,7 @@
> #include <math-barriers.h>
> #include <fenv_private.h>
> #include <libm-alias-float.h>
> +#include <math-use-builtins.h>
>
> /* This implementation relies on double being more than twice as
> precise as float and uses rounding to odd in order to avoid problems
> @@ -33,6 +34,10 @@
> float
> __fmaf (float x, float y, float z)
> {
> +#if USE_FMAF_BUILTIN
> + return __builtin_fmaf (x, y, z);
> +#else
> + /* Use generic implementation. */
> fenv_t env;
>
> /* Multiplication is always exact. */
> @@ -60,6 +65,7 @@ __fmaf (float x, float y, float z)
>
> /* And finally truncation with round to nearest. */
> return (float) u.d;
> +#endif /* ! USE_FMAF_BUILTIN */
> }
> #ifndef __fmaf
> libm_alias_float (__fma, fma)
> diff --git a/sysdeps/ieee754/float128/float128_private.h b/sysdeps/ieee754/float128/float128_private.h
> index f97463d9dc1b..ab6fc9f3c9cf 100644
> --- a/sysdeps/ieee754/float128/float128_private.h
> +++ b/sysdeps/ieee754/float128/float128_private.h
> @@ -154,6 +154,8 @@
> #define USE_ROUNDL_BUILTIN USE_ROUNDF128_BUILTIN
> #undef USE_COPYSIGNL_BUILTIN
> #define USE_COPYSIGNL_BUILTIN USE_COPYSIGNF128_BUILTIN
> +#undef USE_FMAL_BUILTIN
> +#define USE_FMAL_BUILTIN USE_FMAF128_BUILTIN
>
> /* IEEE function renames. */
> #define __ieee754_acoshl __ieee754_acoshf128
> diff --git a/sysdeps/ieee754/ldbl-128/s_fmal.c b/sysdeps/ieee754/ldbl-128/s_fmal.c
> index 7475015bcec6..a610499e47c7 100644
> --- a/sysdeps/ieee754/ldbl-128/s_fmal.c
> +++ b/sysdeps/ieee754/ldbl-128/s_fmal.c
> @@ -25,6 +25,7 @@
> #include <math_private.h>
> #include <libm-alias-ldouble.h>
> #include <tininess.h>
> +#include <math-use-builtins.h>
>
> /* This implementation uses rounding to odd to avoid problems with
> double rounding. See a paper by Boldo and Melquiond:
> @@ -33,6 +34,9 @@
> _Float128
> __fmal (_Float128 x, _Float128 y, _Float128 z)
> {
> +#if USE_FMAL_BUILTIN
> + return __builtin_fmal (x, y, z);
> +#else
> union ieee854_long_double u, v, w;
> int adjust = 0;
> u.d = x;
> @@ -296,5 +300,6 @@ __fmal (_Float128 x, _Float128 y, _Float128 z)
> v.ieee.mantissa3 |= j;
> return v.d * L(0x1p-228);
> }
> +#endif /* ! USE_FMAL_BUILTIN */
> }
> libm_alias_ldouble (__fma, fma)
>
On 6/2/20 10:27 AM, Adhemerval Zanella via Libc-alpha wrote:
>> I used commit f82996f815 "Use GCC builtins for round functions if desired" as
>> starting point for my change. And seems it was not an ideal reference :-) as round
>> has far fewer instances than fma. Indeed fma is present in ldbl-128 and dbl-64 so
>> needs updating in both.
> I think after this set is upstream I will refactor to make each symbol and its
> variant (i.g sqrt, sqrtf, etc.) to be define on its own file. The default
> math-use-builtins will then include each file:
>
> /* math-use-builtins.h */
> #inclde <math-use-builtins-sqrt.h>
> [...]
>
> With default USE_* begin 0. This would allow to add new builtin usage without
> require to sync with every architecture (and without breaking its build as well).
OK !
On 6/2/20 7:13 PM, Vineet Gupta wrote:
> On 6/2/20 5:51 AM, Stefan Liebler via Libc-alpha wrote:
>> #endif /* math-use-builtins.h */
>> Please also update the current architecture specific math-use-builtins.h
>> file: sysdeps/s390/fpu/math-use-builtins.h
>> Otherwise it will break build on s390x.
>
> Done.
>
>>> diff --git a/sysdeps/ieee754/dbl-64/s_fma.c b/sysdeps/ieee754/dbl-64/s_fma.c
>>> index 876df6e78bdc..9dc5b132b9ee 100644
>>> --- a/sysdeps/ieee754/dbl-64/s_fma.c
>>> +++ b/sysdeps/ieee754/dbl-64/s_fma.c
>>> @@ -25,6 +25,7 @@
>>> #include <fenv_private.h>
>>> #include <libm-alias-double.h>
>>> #include <tininess.h>
>>> +#include <math-use-builtins.h>
>>>
>>> /* This implementation uses rounding to odd to avoid problems with
>>> double rounding. See a paper by Boldo and Melquiond:
>>> @@ -33,6 +34,10 @@
>>> double
>>> __fma (double x, double y, double z)
>>> {
>>> +#if USE_FMA_BUILTIN
>>> + return __builtin_fma (x, y, z);
>>
>> Architectures which have support for ldbl-128 will use the file
>> sysdeps/ieee754/ldbl-128/s_fma.c instead of
>> sysdeps/ieee754/dbl-64/s_fma.c. Should this file also be adjusted in
>> order to use the builtin if USE_FMA_BUILTIN is set to one?
>
> Right.
>
> I used commit f82996f815 "Use GCC builtins for round functions if desired" as
> starting point for my change. And seems it was not an ideal reference :-) as round
> has far fewer instances than fma. Indeed fma is present in ldbl-128 and dbl-64 so
> needs updating in both.
>
> But just to be sure s390 is currently not using the newly introduced builtins so
> I'll keep them as follows.
>
> #define USE_SQRT_BUILTIN 0
> #define USE_SQRTF_BUILTIN 0
>
> #define USE_FMA_BUILTIN 0
> #define USE_FMAF_BUILTIN 0
> #define USE_FMAL_BUILTIN 0
> #define USE_FMAF128_BUILTIN 0
>
Yes. Those should be disabled for now in order to not break anything. As
soon as you've committed your patches, I'll have a look if I can
activate some of them and remove s390 specific implementations. But I
first have to check with the gcc guys, if the builtins are always
expanded correctly in various gcc versions.
Thanks.
Stefan
> -Vineet
>
@@ -63,4 +63,9 @@
#define USE_SQRT_BUILTIN 0
#define USE_SQRTF_BUILTIN 0
+#define USE_FMA_BUILTIN 0
+#define USE_FMAF_BUILTIN 0
+#define USE_FMAL_BUILTIN 0
+#define USE_FMAF128_BUILTIN 0
+
#endif /* math-use-builtins.h */
@@ -25,6 +25,7 @@
#include <fenv_private.h>
#include <libm-alias-double.h>
#include <tininess.h>
+#include <math-use-builtins.h>
/* This implementation uses rounding to odd to avoid problems with
double rounding. See a paper by Boldo and Melquiond:
@@ -33,6 +34,10 @@
double
__fma (double x, double y, double z)
{
+#if USE_FMA_BUILTIN
+ return __builtin_fma (x, y, z);
+#else
+ /* Use generic implementation. */
union ieee754_double u, v, w;
int adjust = 0;
u.d = x;
@@ -292,6 +297,7 @@ __fma (double x, double y, double z)
v.ieee.mantissa1 |= j;
return v.d * 0x1p-108;
}
+#endif /* ! USE_FMA_BUILTIN */
}
#ifndef __fma
libm_alias_double (__fma, fma)
@@ -23,6 +23,7 @@
#include <math-barriers.h>
#include <fenv_private.h>
#include <libm-alias-float.h>
+#include <math-use-builtins.h>
/* This implementation relies on double being more than twice as
precise as float and uses rounding to odd in order to avoid problems
@@ -33,6 +34,10 @@
float
__fmaf (float x, float y, float z)
{
+#if USE_FMAF_BUILTIN
+ return __builtin_fmaf (x, y, z);
+#else
+ /* Use generic implementation. */
fenv_t env;
/* Multiplication is always exact. */
@@ -60,6 +65,7 @@ __fmaf (float x, float y, float z)
/* And finally truncation with round to nearest. */
return (float) u.d;
+#endif /* ! USE_FMAF_BUILTIN */
}
#ifndef __fmaf
libm_alias_float (__fma, fma)
@@ -154,6 +154,8 @@
#define USE_ROUNDL_BUILTIN USE_ROUNDF128_BUILTIN
#undef USE_COPYSIGNL_BUILTIN
#define USE_COPYSIGNL_BUILTIN USE_COPYSIGNF128_BUILTIN
+#undef USE_FMAL_BUILTIN
+#define USE_FMAL_BUILTIN USE_FMAF128_BUILTIN
/* IEEE function renames. */
#define __ieee754_acoshl __ieee754_acoshf128
@@ -25,6 +25,7 @@
#include <math_private.h>
#include <libm-alias-ldouble.h>
#include <tininess.h>
+#include <math-use-builtins.h>
/* This implementation uses rounding to odd to avoid problems with
double rounding. See a paper by Boldo and Melquiond:
@@ -33,6 +34,9 @@
_Float128
__fmal (_Float128 x, _Float128 y, _Float128 z)
{
+#if USE_FMAL_BUILTIN
+ return __builtin_fmal (x, y, z);
+#else
union ieee854_long_double u, v, w;
int adjust = 0;
u.d = x;
@@ -296,5 +300,6 @@ __fmal (_Float128 x, _Float128 y, _Float128 z)
v.ieee.mantissa3 |= j;
return v.d * L(0x1p-228);
}
+#endif /* ! USE_FMAL_BUILTIN */
}
libm_alias_ldouble (__fma, fma)