[v2,1/4] iee754: provide gcc builtins based generic sqrt functions
Commit Message
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
---
sysdeps/generic/math-use-builtins.h | 3 +++
sysdeps/ieee754/dbl-64/e_sqrt.c | 6 ++++++
sysdeps/ieee754/flt-32/e_sqrtf.c | 16 ++++++++++------
3 files changed, 19 insertions(+), 6 deletions(-)
Comments
On 6/2/20 2:35 AM, Vineet Gupta via Libc-alpha wrote:
> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
> ---
> sysdeps/generic/math-use-builtins.h | 3 +++
> sysdeps/ieee754/dbl-64/e_sqrt.c | 6 ++++++
> sysdeps/ieee754/flt-32/e_sqrtf.c | 16 ++++++++++------
> 3 files changed, 19 insertions(+), 6 deletions(-)
>
> diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
> index 8a39ef58bc95..fc724c824a17 100644
> --- a/sysdeps/generic/math-use-builtins.h
> +++ b/sysdeps/generic/math-use-builtins.h
> @@ -60,4 +60,7 @@
> # define USE_COPYSIGNF128_BUILTIN 0
> #endif
>
> +#define USE_SQRT_BUILTIN 0
> +#define USE_SQRTF_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
On 6/2/20 5:51 AM, Stefan Liebler via Libc-alpha wrote:
> On 6/2/20 2:35 AM, Vineet Gupta via Libc-alpha wrote:
>> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
>> ---
>> sysdeps/generic/math-use-builtins.h | 3 +++
>> sysdeps/ieee754/dbl-64/e_sqrt.c | 6 ++++++
>> sysdeps/ieee754/flt-32/e_sqrtf.c | 16 ++++++++++------
>> 3 files changed, 19 insertions(+), 6 deletions(-)
>>
>> diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
>> index 8a39ef58bc95..fc724c824a17 100644
>> --- a/sysdeps/generic/math-use-builtins.h
>> +++ b/sysdeps/generic/math-use-builtins.h
>> @@ -60,4 +60,7 @@
>> # define USE_COPYSIGNF128_BUILTIN 0
>> #endif
>>
>> +#define USE_SQRT_BUILTIN 0
>> +#define USE_SQRTF_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
Fixed. I should have added s390 to my list of arches to test.
Thx for taking a look.
-Vineet
On 01/06/2020 21:35, Vineet Gupta wrote:
> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
LGTM with the small nit below and the s390 fix pointed by Stefan.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
> ---
> sysdeps/generic/math-use-builtins.h | 3 +++
> sysdeps/ieee754/dbl-64/e_sqrt.c | 6 ++++++
> sysdeps/ieee754/flt-32/e_sqrtf.c | 16 ++++++++++------
> 3 files changed, 19 insertions(+), 6 deletions(-)
>
> diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
> index 8a39ef58bc95..fc724c824a17 100644
> --- a/sysdeps/generic/math-use-builtins.h
> +++ b/sysdeps/generic/math-use-builtins.h
> @@ -60,4 +60,7 @@
> # define USE_COPYSIGNF128_BUILTIN 0
> #endif
>
> +#define USE_SQRT_BUILTIN 0
> +#define USE_SQRTF_BUILTIN 0
> +
> #endif /* math-use-builtins.h */
Ok.
> diff --git a/sysdeps/ieee754/dbl-64/e_sqrt.c b/sysdeps/ieee754/dbl-64/e_sqrt.c
> index d42a1a4eb6e9..518a8ae5cdaf 100644
> --- a/sysdeps/ieee754/dbl-64/e_sqrt.c
> +++ b/sysdeps/ieee754/dbl-64/e_sqrt.c
> @@ -41,6 +41,7 @@
> #include <math_private.h>
> #include <fenv_private.h>
> #include <libm-alias-finite.h>
> +#include <math-use-builtins.h>
>
> /*********************************************************************/
> /* An ultimate sqrt routine. Given an IEEE double machine number x */
> @@ -50,6 +51,10 @@
> double
> __ieee754_sqrt (double x)
> {
> +#if USE_SQRT_BUILTIN
> + return __builtin_sqrt (x);
> +#else
> + /* Use generic implementation. */
> static const double
> rt0 = 9.99999999859990725855365213134618E-01,
> rt1 = 4.99999999495955425917856814202739E-01,
> @@ -138,6 +143,7 @@ __ieee754_sqrt (double x)
> return (x - x) / (x - x); /* sqrt(-ve)=sNaN */
> return 0x1p-256 * __ieee754_sqrt (x * 0x1p512);
> }
> +#endif /* ! USE_SQRT_BUILTIN */
> }
> #ifndef __ieee754_sqrt
> libm_alias_finite (__ieee754_sqrt, __sqrt)
Ok.
> diff --git a/sysdeps/ieee754/flt-32/e_sqrtf.c b/sysdeps/ieee754/flt-32/e_sqrtf.c
> index b339444301aa..d85a04162983 100644
> --- a/sysdeps/ieee754/flt-32/e_sqrtf.c
> +++ b/sysdeps/ieee754/flt-32/e_sqrtf.c
> @@ -16,12 +16,15 @@
> #include <math.h>
> #include <math_private.h>
> #include <libm-alias-finite.h>
> -
> -static const float one = 1.0, tiny=1.0e-30;
> +#include <math-use-builtins.h>
>
> float
> __ieee754_sqrtf(float x)
> {
> +#if USE_SQRTF_BUILTIN
> + return __builtin_sqrtf (x);
> +#else
> + /* Use generic implementation. */
> float z;
> int32_t sign = (int)0x80000000;
> int32_t ix,s,q,m,t,i;
> @@ -70,10 +73,10 @@ __ieee754_sqrtf(float x)
>
> /* use floating add to find out rounding direction */
> if(ix!=0) {
> - z = one-tiny; /* trigger inexact flag */
> - if (z>=one) {
> - z = one+tiny;
> - if (z>one)
> + z = 0x1p0 - 0x1.4484cp-100; /* trigger inexact flag */
Period and double space before '*/'.
> + if (z >= 0x1p0) {
> + z = 0x1p0 + 0x1.4484cp-100;
> + if (z > 0x1p0)
> q += 2;
> else
> q += (q&1);
> @@ -83,6 +86,7 @@ __ieee754_sqrtf(float x)
> ix += (m <<23);
> SET_FLOAT_WORD(z,ix);
> return z;
> +#endif /* ! USE_SQRTF_BUILTIN */
> }
> #ifndef __ieee754_sqrtf
> libm_alias_finite (__ieee754_sqrtf, __sqrtf)
>
Ok.
@@ -60,4 +60,7 @@
# define USE_COPYSIGNF128_BUILTIN 0
#endif
+#define USE_SQRT_BUILTIN 0
+#define USE_SQRTF_BUILTIN 0
+
#endif /* math-use-builtins.h */
@@ -41,6 +41,7 @@
#include <math_private.h>
#include <fenv_private.h>
#include <libm-alias-finite.h>
+#include <math-use-builtins.h>
/*********************************************************************/
/* An ultimate sqrt routine. Given an IEEE double machine number x */
@@ -50,6 +51,10 @@
double
__ieee754_sqrt (double x)
{
+#if USE_SQRT_BUILTIN
+ return __builtin_sqrt (x);
+#else
+ /* Use generic implementation. */
static const double
rt0 = 9.99999999859990725855365213134618E-01,
rt1 = 4.99999999495955425917856814202739E-01,
@@ -138,6 +143,7 @@ __ieee754_sqrt (double x)
return (x - x) / (x - x); /* sqrt(-ve)=sNaN */
return 0x1p-256 * __ieee754_sqrt (x * 0x1p512);
}
+#endif /* ! USE_SQRT_BUILTIN */
}
#ifndef __ieee754_sqrt
libm_alias_finite (__ieee754_sqrt, __sqrt)
@@ -16,12 +16,15 @@
#include <math.h>
#include <math_private.h>
#include <libm-alias-finite.h>
-
-static const float one = 1.0, tiny=1.0e-30;
+#include <math-use-builtins.h>
float
__ieee754_sqrtf(float x)
{
+#if USE_SQRTF_BUILTIN
+ return __builtin_sqrtf (x);
+#else
+ /* Use generic implementation. */
float z;
int32_t sign = (int)0x80000000;
int32_t ix,s,q,m,t,i;
@@ -70,10 +73,10 @@ __ieee754_sqrtf(float x)
/* use floating add to find out rounding direction */
if(ix!=0) {
- z = one-tiny; /* trigger inexact flag */
- if (z>=one) {
- z = one+tiny;
- if (z>one)
+ z = 0x1p0 - 0x1.4484cp-100; /* trigger inexact flag */
+ if (z >= 0x1p0) {
+ z = 0x1p0 + 0x1.4484cp-100;
+ if (z > 0x1p0)
q += 2;
else
q += (q&1);
@@ -83,6 +86,7 @@ __ieee754_sqrtf(float x)
ix += (m <<23);
SET_FLOAT_WORD(z,ix);
return z;
+#endif /* ! USE_SQRTF_BUILTIN */
}
#ifndef __ieee754_sqrtf
libm_alias_finite (__ieee754_sqrtf, __sqrtf)