math: Use acosf from CORE-MATH

The CORE-MATH implementation is correctly rounded (for any rounding mode)
and shows slight better performance to the generic acosf.

The code was adapted to glibc style and to use the definition of
math_config.h (to handle errno, overflow, and underflow).

Benchtest on x64_64 (Ryzen 9 5900X, gcc 14.2.1), aarch64 (Neoverse-N1,
gcc 13.3.1), and powerpc (POWER10, gcc 13.2.1):

Latency                      master        patched   improvement
x86_64                      52.5098        36.6312        30.24%
x86_64v2                    53.0217        37.3091        29.63%
x86_64v3                    42.8501        32.3977        24.39%
i686                       207.3960       109.4000        47.25%
aarch64                     21.3694        13.7871        35.48%
power10                     14.5542         7.2891        49.92%

reciprocal-throughput        master        patched   improvement
x86_64                      14.1487        15.9508       -12.74%
x86_64v2                    14.3293        16.1899       -12.98%
x86_64v3                    13.6563        12.6161         7.62%
i686                       158.4060        45.7354        71.13%
aarch64                     12.5515        9.19233        26.76%
power10                      5.7868         3.3487        42.13%

Signed-off-by: Alexei Sibidanov <sibid@uvic.ca>
Signed-off-by: Paul Zimmermann <Paul.Zimmermann@inria.fr>
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: DJ Delorie <dj@redhat.com>
This commit is contained in:
Adhemerval Zanella 2024-10-18 16:04:30 -03:00
parent 45126f866c
commit 66fa7ad437
27 changed files with 136 additions and 174 deletions

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@ -294,3 +294,7 @@ sysdeps/ieee754/flt-32/s_tanf.c:
functions to handle errno, overflow, and underflow. It was changed
to use an internal wrapper for 128 bit unsigned integer operations
for ABIs that do not support the type natively.
sysdeps/ieee754/flt-32/e_acosf.c:
(src/binary32/acos/acosf.c in CORE-MATH)
- The code was adapted to use glibc code style and internal
functions to handle errno, overflow, and underflow.

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@ -3,7 +3,6 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
ldouble: 1
Function: "acos_advsimd":
@ -12,7 +11,6 @@ float: 1
Function: "acos_downward":
double: 1
float: 1
ldouble: 1
Function: "acos_sve":
@ -21,12 +19,10 @@ float: 1
Function: "acos_towardzero":
double: 1
float: 1
ldouble: 1
Function: "acos_upward":
double: 1
float: 1
ldouble: 1
Function: "acosh":

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@ -3,22 +3,18 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
ldouble: 1
Function: "acos_downward":
double: 1
float: 1
ldouble: 1
Function: "acos_towardzero":
double: 1
float: 1
ldouble: 1
Function: "acos_upward":
double: 1
float: 1
ldouble: 1
Function: "acosh":

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@ -3,19 +3,15 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
Function: "acos_downward":
double: 1
float: 1
Function: "acos_towardzero":
double: 1
float: 1
Function: "acos_upward":
double: 1
float: 1
Function: "acosh":
double: 3

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@ -3,7 +3,6 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
Function: "acosh":
double: 2

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@ -3,19 +3,15 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
Function: "acos_downward":
double: 1
float: 1
Function: "acos_towardzero":
double: 1
float: 1
Function: "acos_upward":
double: 1
float: 1
Function: "acosh":
double: 2

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@ -2,19 +2,15 @@
# Maximal error of functions:
Function: "acos":
float: 1
Function: "acos_downward":
double: 1
float: 1
Function: "acos_towardzero":
double: 1
float: 1
Function: "acos_upward":
double: 1
float: 1
Function: "acosh":
double: 2

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@ -2,19 +2,15 @@
# Maximal error of functions:
Function: "acos":
float: 1
Function: "acos_downward":
double: 1
float: 1
Function: "acos_towardzero":
double: 1
float: 1
Function: "acos_upward":
double: 1
float: 1
Function: "acosh":
double: 2

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@ -3,19 +3,15 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
Function: "acos_downward":
double: 1
float: 1
Function: "acos_towardzero":
double: 1
float: 1
Function: "acos_upward":
double: 1
float: 1
Function: "acosh":
double: 2

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@ -1,23 +0,0 @@
/*
* Public domain.
*/
#include <machine/asm.h>
#include <libm-alias-finite.h>
RCSID("$NetBSD: $")
/* acos = atan (sqrt(1 - x^2) / x) */
ENTRY(__ieee754_acosf)
flds 4(%esp) /* x */
fld %st
fmul %st(0) /* x^2 */
fld1
fsubp /* 1 - x^2 */
fsqrt /* sqrt (1 - x^2) */
fabs
fxch %st(1)
fpatan
ret
END (__ieee754_acosf)
libm_alias_finite (__ieee754_acosf, __acosf)

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@ -47,13 +47,13 @@ ldouble: 1
Function: "acospi_downward":
double: 1
float: 1
float: 2
float128: 1
ldouble: 3
Function: "acospi_towardzero":
double: 1
float: 1
float: 2
float128: 1
ldouble: 3

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@ -47,13 +47,13 @@ ldouble: 1
Function: "acospi_downward":
double: 1
float: 1
float: 2
float128: 1
ldouble: 3
Function: "acospi_towardzero":
double: 1
float: 1
float: 2
float128: 1
ldouble: 3

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@ -1,78 +1,139 @@
/* e_acosf.c -- float version of e_acos.c.
*/
/* Correctly-rounded arc-cosine function for binary32 value.
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
Copyright (c) 2023-2024 Alexei Sibidanov.
The original version of this file was copied from the CORE-MATH
project (file src/binary32/acos/acosf.c, revision 61d7bef).
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
#include <errno.h>
#include <math.h>
#include <math_private.h>
#include <libm-alias-finite.h>
#include "math_config.h"
static const float
one = 1.0000000000e+00, /* 0x3F800000 */
pi = 3.1415925026e+00, /* 0x40490fda */
pio2_hi = 1.5707962513e+00, /* 0x3fc90fda */
pio2_lo = 7.5497894159e-08, /* 0x33a22168 */
pS0 = 1.6666667163e-01, /* 0x3e2aaaab */
pS1 = -3.2556581497e-01, /* 0xbea6b090 */
pS2 = 2.0121252537e-01, /* 0x3e4e0aa8 */
pS3 = -4.0055535734e-02, /* 0xbd241146 */
pS4 = 7.9153501429e-04, /* 0x3a4f7f04 */
pS5 = 3.4793309169e-05, /* 0x3811ef08 */
qS1 = -2.4033949375e+00, /* 0xc019d139 */
qS2 = 2.0209457874e+00, /* 0x4001572d */
qS3 = -6.8828397989e-01, /* 0xbf303361 */
qS4 = 7.7038154006e-02; /* 0x3d9dc62e */
static __attribute__ ((noinline)) float
as_special (float x)
{
const float pih = 0x1.921fb6p+1;
const float pil = -0x1p-24f;
uint32_t t = asuint (x);
if (t == (0x7fu << 23))
return 0.0f; /* x=1 */
if (t == (0x17fu << 23))
return pih + pil; /* x=-1 */
uint32_t ax = t << 1;
if (ax > (0xffu << 24))
return x + x; /* nan */
return __math_invalidf (0.0);
}
static inline double
poly12 (double z, const double *c)
{
double z2 = z * z, z4 = z2 * z2;
double c0 = c[0] + z * c[1];
double c2 = c[2] + z * c[3];
double c4 = c[4] + z * c[5];
double c6 = c[6] + z * c[7];
double c8 = c[8] + z * c[9];
double c10 = c[10] + z * c[11];
c0 += c2 * z2;
c4 += c6 * z2;
c8 += z2 * c10;
c0 += z4 * (c4 + z4 * c8);
return c0;
}
float
__ieee754_acosf(float x)
__ieee754_acosf (float x)
{
float z,p,q,r,w,s,c,df;
int32_t hx,ix;
GET_FLOAT_WORD(hx,x);
ix = hx&0x7fffffff;
if(ix==0x3f800000) { /* |x|==1 */
if(hx>0) return 0.0; /* acos(1) = 0 */
else return pi+(float)2.0*pio2_lo; /* acos(-1)= pi */
} else if(ix>0x3f800000) { /* |x| >= 1 */
return (x-x)/(x-x); /* acos(|x|>1) is NaN */
}
if(ix<0x3f000000) { /* |x| < 0.5 */
if(ix<=0x32800000) return pio2_hi+pio2_lo;/*if|x|<=2**-26*/
z = x*x;
p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*pS5)))));
q = one+z*(qS1+z*(qS2+z*(qS3+z*qS4)));
r = p/q;
return pio2_hi - (x - (pio2_lo-x*r));
} else if (hx<0) { /* x < -0.5 */
z = (one+x)*(float)0.5;
p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*pS5)))));
q = one+z*(qS1+z*(qS2+z*(qS3+z*qS4)));
s = sqrtf(z);
r = p/q;
w = r*s-pio2_lo;
return pi - (float)2.0*(s+w);
} else { /* x > 0.5 */
int32_t idf;
z = (one-x)*(float)0.5;
s = sqrtf(z);
df = s;
GET_FLOAT_WORD(idf,df);
SET_FLOAT_WORD(df,idf&0xfffff000);
c = (z-df*df)/(s+df);
p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*pS5)))));
q = one+z*(qS1+z*(qS2+z*(qS3+z*qS4)));
r = p/q;
w = r*s+c;
return (float)2.0*(df+w);
}
const double pi2 = 0x1.921fb54442d18p+0;
static const double o[] = { 0, 0x1.921fb54442d18p+1 };
double xs = x;
double r;
uint32_t t = asuint (x);
uint32_t ax = t << 1;
if (__glibc_unlikely (ax >= 0x7f<<24))
return as_special (x);
if (__glibc_likely (ax < 0x7ec2a1dcu)) /* |x| < 0x1.c2a1dcp-1 */
{
static const double b[] =
{
0x1.fffffffd9ccb8p-1, 0x1.5555c94838007p-3, 0x1.32ded4b7c20fap-4,
0x1.8566df703309ep-5, -0x1.980c959bec9a3p-6, 0x1.56fbb04998344p-1,
-0x1.403d8e4c49f52p+2, 0x1.b06c3e9f311eap+4, -0x1.9ea97c4e2c21fp+6,
0x1.200b8261cc61bp+8, -0x1.2274c2799a5c7p+9, 0x1.a558a59cc19d3p+9,
-0x1.aca4b6a529ffp+9, 0x1.228744703f813p+9, -0x1.d7dbb0b322228p+7,
0x1.5c2018c0c0105p+5
};
/* Avoid spurious underflow exception. */
if (__glibc_unlikely (ax <= 0x40000000u)) /* |x| < 2^-63 */
return (float) pi2;
double z = xs;
double z2 = z * z;
double z4 = z2 * z2;
double z8 = z4 * z4;
double z16 = z8 * z8;
r = z * ((((b[0] + z2 * b[1]) + z4 * (b[2] + z2 * b[3]))
+ z8 * ((b[4] + z2 * b[5]) + z4 * (b[6] + z2 * b[7])))
+ z16 * (((b[8] + z2 * b[9]) + z4 * (b[10] + z2 * b[11]))
+ z8
* ((b[12] + z2 * b[13])+ z4 * (b[14] + z2 * b[15]))));
float ub = 0x1.921fb54574191p+0 - r;
float lb = 0x1.921fb543118ap+0 - r;
if (ub == lb)
return ub;
}
/* accurate path */
if (ax < (0x7eu << 24))
{
static const double c[] =
{
0x1.555555555529cp-3, 0x1.333333337e0ddp-4, 0x1.6db6db3b4465ep-5,
0x1.f1c72e13ac306p-6, 0x1.6e89cebe06bc4p-6, 0x1.1c6dcf5289094p-6,
0x1.c6dbbcc7c6315p-7, 0x1.8f8dc2615e996p-7, 0x1.a5833b7bf15e8p-8,
0x1.43f44ace1665cp-6, -0x1.0fb17df881c73p-6, 0x1.07520c026b2d6p-5
};
if (t == 0x328885a3u)
return 0x1.921fb6p+0f + 0x1p-25;
if (t == 0x39826222u)
return 0x1.920f6ap+0f + 0x1p-25;
double x2 = xs * xs;
r = (pi2 - xs) - (xs * x2) * poly12 (x2, c);
}
else
{
static const double c[] =
{
0x1.6a09e667f3bcbp+0, 0x1.e2b7dddff2db9p-4, 0x1.b27247ab42dbcp-6,
0x1.02995cc4e0744p-7, 0x1.5ffb0276ec8eap-9, 0x1.033885a928decp-10,
0x1.911f2be23f8c7p-12, 0x1.4c3c55d2437fdp-13, 0x1.af477e1d7b461p-15,
0x1.abd6bdff67dcbp-15, -0x1.1717e86d0fa28p-16, 0x1.6ff526de46023p-16
};
double bx = fabs (xs);
double z = 1.0 - bx;
double s = copysign (sqrt (z), xs);
r = o[t >> 31] + s * poly12 (z, c);
}
return r;
}
libm_alias_finite (__ieee754_acosf, __acosf)

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@ -3,22 +3,18 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
ldouble: 1
Function: "acos_downward":
double: 1
float: 1
ldouble: 1
Function: "acos_towardzero":
double: 1
float: 1
ldouble: 1
Function: "acos_upward":
double: 1
float: 1
ldouble: 1
Function: "acosh":

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@ -2,7 +2,6 @@
# Maximal error of functions:
Function: "acos":
float: 1
Function: "acosh":
double: 2

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@ -3,19 +3,15 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
Function: "acos_downward":
double: 1
float: 1
Function: "acos_towardzero":
double: 1
float: 1
Function: "acos_upward":
double: 1
float: 1
Function: "acosh":
double: 2

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@ -3,22 +3,18 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
ldouble: 1
Function: "acos_downward":
double: 1
float: 1
ldouble: 1
Function: "acos_towardzero":
double: 1
float: 1
ldouble: 1
Function: "acos_upward":
double: 1
float: 1
ldouble: 1
Function: "acosh":

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@ -3,19 +3,15 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
Function: "acos_downward":
double: 1
float: 1
Function: "acos_towardzero":
double: 1
float: 1
Function: "acos_upward":
double: 1
float: 1
Function: "acosh":
double: 2

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@ -3,19 +3,15 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
Function: "acos_downward":
double: 1
float: 1
Function: "acos_towardzero":
double: 1
float: 1
Function: "acos_upward":
double: 1
float: 1
Function: "acosh":
double: 2

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@ -3,25 +3,21 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
float128: 1
ldouble: 1
Function: "acos_downward":
double: 1
float: 1
float128: 1
ldouble: 3
Function: "acos_towardzero":
double: 1
float: 1
float128: 1
ldouble: 3
Function: "acos_upward":
double: 1
float: 1
float128: 1
ldouble: 2

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@ -3,22 +3,18 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
ldouble: 1
Function: "acos_downward":
double: 1
float: 1
ldouble: 3
Function: "acos_towardzero":
double: 1
float: 1
ldouble: 3
Function: "acos_upward":
double: 1
float: 1
ldouble: 2
Function: "acosh":

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@ -3,22 +3,18 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
ldouble: 1
Function: "acos_downward":
double: 1
float: 1
ldouble: 1
Function: "acos_towardzero":
double: 1
float: 1
ldouble: 1
Function: "acos_upward":
double: 1
float: 1
ldouble: 1
Function: "acosh":

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@ -3,22 +3,18 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
ldouble: 1
Function: "acos_downward":
double: 1
float: 1
ldouble: 1
Function: "acos_towardzero":
double: 1
float: 1
ldouble: 1
Function: "acos_upward":
double: 1
float: 1
ldouble: 1
Function: "acosh":

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@ -3,22 +3,18 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
ldouble: 1
Function: "acos_downward":
double: 1
float: 1
ldouble: 1
Function: "acos_towardzero":
double: 1
float: 1
ldouble: 1
Function: "acos_upward":
double: 1
float: 1
ldouble: 1
Function: "acosh":

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@ -2,11 +2,9 @@
# Maximal error of functions:
Function: "acos":
float: 1
Function: "acos_towardzero":
double: 1
float: 1
Function: "acosh":
double: 2

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@ -3,22 +3,18 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
ldouble: 1
Function: "acos_downward":
double: 1
float: 1
ldouble: 1
Function: "acos_towardzero":
double: 1
float: 1
ldouble: 1
Function: "acos_upward":
double: 1
float: 1
ldouble: 1
Function: "acosh":

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@ -3,25 +3,21 @@
# Maximal error of functions:
Function: "acos":
double: 1
float: 1
float128: 1
ldouble: 2
Function: "acos_downward":
double: 1
float: 1
float128: 1
ldouble: 2
Function: "acos_towardzero":
double: 1
float: 1
float128: 1
ldouble: 2
Function: "acos_upward":
double: 1
float: 1
float128: 1
ldouble: 2