From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: Vineet Gupta <Vineet.Gupta1@synopsys.com>, libc-alpha@sourceware.org
Cc: linux-snps-arc@lists.infradead.org
Subject: Re: [PATCH 2/5] iee754: prvoide gcc builtins based generic sqrt functions
Date: Mon, 1 Jun 2020 11:42:06 -0300 [thread overview]
Message-ID: <45540801-e568-54ef-ad29-c3c2130eddb5@linaro.org> (raw)
In-Reply-To: <1f8c98ba-481c-1463-29ff-c0dec7add324@linaro.org>
On 01/06/2020 11:13, Adhemerval Zanella wrote:
>
>
> On 29/05/2020 23:00, Vineet Gupta wrote:
>
> LGTM, thanks.
>
> 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 | 6 ++++++
>> 3 files changed, 15 insertions(+)
>>
>> 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 */
>
> Ok.
>
>> @@ -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..68fc80e1e1ee 100644
>> --- a/sysdeps/ieee754/flt-32/e_sqrtf.c
>> +++ b/sysdeps/ieee754/flt-32/e_sqrtf.c
>> @@ -16,12 +16,17 @@
>> #include <math.h>
>> #include <math_private.h>
>> #include <libm-alias-finite.h>
>> +#include <math-use-builtins.h>
>>
>> static const float one = 1.0, tiny=1.0e-30;
You will need to move this definitions inside the !USE_SQRTF_BUILTIN
to avoid defined by not used warnings. Current practice is to just
open code the constants and let compiler optimize the constant pool:
diff --git a/sysdeps/ieee754/flt-32/e_sqrtf.c b/sysdeps/ieee754/flt-32/e_sqrtf.c
index 68fc80e..d85a041 100644
--- a/sysdeps/ieee754/flt-32/e_sqrtf.c
+++ b/sysdeps/ieee754/flt-32/e_sqrtf.c
@@ -18,8 +18,6 @@
#include <libm-alias-finite.h>
#include <math-use-builtins.h>
-static const float one = 1.0, tiny=1.0e-30;
-
float
__ieee754_sqrtf(float x)
{
@@ -75,10 +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);
>>
>> 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;
>> @@ -83,6 +88,7 @@ __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.
>
next prev parent reply other threads:[~2020-06-01 14:42 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-30 2:00 [PATCH 0/5] use gcc builtins for sqrt and fma functions Vineet Gupta
2020-05-30 2:00 ` [PATCH 1/5] ARC/dl-runtime helper macros Vineet Gupta
2020-05-30 2:17 ` Vineet Gupta
2020-05-30 2:00 ` [PATCH 2/5] iee754: prvoide gcc builtins based generic sqrt functions Vineet Gupta
2020-06-01 14:13 ` Adhemerval Zanella
2020-06-01 14:42 ` Adhemerval Zanella [this message]
2020-06-01 18:12 ` Vineet Gupta
2020-06-01 18:32 ` Adhemerval Zanella
2020-06-01 14:18 ` Florian Weimer
2020-06-01 18:12 ` Vineet Gupta
2020-05-30 2:00 ` [PATCH 3/5] iee754: prvoide gcc builtins based generic fma functions Vineet Gupta
2020-06-01 14:20 ` Adhemerval Zanella
2020-06-01 16:13 ` Florian Weimer
2020-05-30 2:00 ` [PATCH 4/5] aarch/fpu: use generic sqrt, " Vineet Gupta
2020-06-01 16:38 ` Adhemerval Zanella
2020-06-01 21:44 ` Vineet Gupta
2020-06-01 22:08 ` Ramana Radhakrishnan
2020-06-02 18:12 ` Joseph Myers
2020-05-30 2:00 ` [PATCH 5/5] powerpc/fpu: use generic " Vineet Gupta
2020-06-01 17:10 ` Adhemerval Zanella
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