All of lore.kernel.org
 help / color / mirror / Atom feed
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.
> 

_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=45540801-e568-54ef-ad29-c3c2130eddb5@linaro.org \
    --to=adhemerval.zanella@linaro.org \
    --cc=Vineet.Gupta1@synopsys.com \
    --cc=libc-alpha@sourceware.org \
    --cc=linux-snps-arc@lists.infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.