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Merged
merged 21 commits into from
Oct 15, 2024
Merged

[libc] Add sinpif16 function #110994

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1dd121c
add sinpif16 function implementation and unittests
wldfngrs Sep 23, 2024
d7bbbc2
clang format changes
wldfngrs Sep 23, 2024
3255302
Merge branch 'llvm:main' into add_sinpif16_function
wldfngrs Oct 3, 2024
663fbd5
add implementation of sinpif16 function
wldfngrs Oct 3, 2024
0f038fe
clang format
wldfngrs Oct 3, 2024
c54defc
clang format
wldfngrs Oct 3, 2024
a8f7484
nit changes and review suggestions
wldfngrs Oct 7, 2024
3f2282c
fix dependency misspell
wldfngrs Oct 7, 2024
6617bf9
updated function implementation to better handle extremely small non-…
wldfngrs Oct 9, 2024
348eea1
added mpfr exhaustive test
wldfngrs Oct 9, 2024
0ad7d39
minor fixes
wldfngrs Oct 11, 2024
0f4af07
changed 0.0 to 0x0.0p0, fixed MPFRUtils computation of mpfr_sinpi(x) …
wldfngrs Oct 11, 2024
24f1173
update mpfr_sinpi implementation
wldfngrs Oct 11, 2024
cacbf19
minor fix
wldfngrs Oct 11, 2024
a543283
minor fixes, documentation update
wldfngrs Oct 11, 2024
743625d
update pr, test branch against bot
wldfngrs Oct 13, 2024
9f85a85
formatting
wldfngrs Oct 14, 2024
ffcbd23
clang-format fix
wldfngrs Oct 14, 2024
d6fad4c
clang-format
wldfngrs Oct 14, 2024
06c9b4b
fixed float16 cast, nit formatting
wldfngrs Oct 14, 2024
87faa10
sort dependencies
wldfngrs Oct 14, 2024
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181 changes: 84 additions & 97 deletions libc/src/math/generic/sinpif16.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5,12 +5,12 @@
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#define M_PI 3.1415925f

#include "src/math/sinpif16.h"
#include "src/__support/FPUtil/FEnvImpl.h"
#include "src/__support/FPUtil/FPBits.h"
#include "src/__support/FPUtil/PolyEval.h"
#include "src/__support/FPUtil/multiply_add.h"
#include "src/__support/FPUtil/nearest_integer.h"
#include "src/__support/common.h"
#include "src/__support/macros/config.h"

Expand All @@ -21,114 +21,70 @@
// HELPER_START
namespace LIBC_NAMESPACE_DECL {

constexpr float PI_OVER_32 = M_PI / 32;
constexpr float PI_OVER_32 = 0x1.921fb6p-4f;

// In Sollya generate 10 coeffecients for a degree-9 chebyshev polynomial
// approximating the sine function in [-pi / 32, pi / 32] with the following
// commands:
// > prec=23;
// > prec=24;
// > TL = chebyshevform(sin(x), 9, [-pi / 32, pi / 32]);
// > TL[0];
const float SIN_COEFF[10] = {
0x1.801p-27, 0x1.000078p0, -0x1.7e98p-14, -0x1.6bf4p-3, 0x1.95ccp-5,
0x1.1baep2, -0x1.030ap3, -0x1.3dap9, 0x1.98e4p8, 0x1.d3d8p14};

0x1.d333p-26, 0x1.000048p0, -0x1.a5d2p-14, -0x1.628588p-3, 0x1.c1eep-5,
0x1.4455p1, -0x1.317a8p3, -0x1.6bb9p8, 0x1.00ef8p9, 0x1.0edcp14
};
// In Sollya generate 10 coefficients for a degree-9 chebyshev polynomial
// approximating the sine function in [-pi/32, pi/32] with the following
// commands:
// > prec = 23;
// > prec = 24;
// > TL = chebyshevform(cos(x), 9, [-pi / 32, pi / 32]);
// > TL[0];
const float COS_COEFF[10] = {
0x1.00001p0, -0x1.48p-17, -0x1.01259cp-1, -0x1.17fp-6, 0x1.283p0,
0x1.5d1p3, -0x1.6278p7, -0x1.c23p10, 0x1.1444p13, 0x1.5fcp16};

0x1.000006p0, 0x1.e1eap-15, -0x1.0071p-1, -0x1.3b56p-4, 0x1.f3dfp-2,
0x1.ccbap4, -0x1.3034p6, -0x1.f817p11, 0x1.fc59p11, 0x1.7079p17
};
// Lookup table for sin(k * pi / 32) with k = 0, ..., 63.
// Table is generated with Sollya as follows:
// > display = hexadecimmal;
// > prec = 23;
// > prec = 24;
// > for k from 0 to 63 do {sin(k * pi/32);};

const float SIN_K_PI_OVER_32[64] = {0,
0x1.917a6cp-4,
0x1.8f8b84p-3,
0x1.294064p-2,
0x1.87de2cp-2,
0x1.e2b5d4p-2,
0x1.1c73b4p-1,
0x1.44cf34p-1,
0x1.6a09e8p-1,
0x1.8bc808p-1,
0x1.a9b664p-1,
0x1.c38b3p-1,
0x1.d906bcp-1,
0x1.e9f414p-1,
0x1.f6297cp-1,
0x1.fd88dcp-1,
0x1p0,
0x1.fd88dcp-1,
0x1.f6297cp-1,
0x1.e9f414p-1,
0x1.d906bcp-1,
0x1.c38b3p-1,
0x1.a9b664p-1,
0x1.8bc808p-1,
0x1.6a09e8p-1,
0x1.44cf34p-1,
0x1.1c73b4p-1,
0x1.e2b5d4p-2,
0x1.87de2cp-2,
0x1.294064p-2,
0x1.8f8b84p-3,
0x1.917a6cp-4,
0,
-0x1.917a6cp-4,
-0x1.8f8b84p-3,
-0x1.294064p-2,
-0x1.87de2cp-2,
-0x1.e2b5d4p-2,
-0x1.1c73b4p-1,
-0x1.44cf34p-1,
-0x1.6a09e8p-1,
-0x1.8bc808p-1,
-0x1.a9b664p-1,
-0x1.c38b3p-1,
-0x1.d906bcp-1,
-0x1.e9f414p-1,
-0x1.f6297cp-1,
-0x1.fd88dcp-1,
-0x1p0,
-0x1.fd88dcp-1,
-0x1.f6297cp-1,
-0x1.e9f414p-1,
-0x1.d906bcp-1,
-0x1.c38b3p-1,
-0x1.a9b664p-1,
-0x1.8bc808p-1,
-0x1.6a09e8p-1,
-0x1.44cf34p-1,
-0x1.1c73b4p-1,
-0x1.e2b5d4p-2,
-0x1.87de2cp-2,
-0x1.294064p-2,
-0x1.8f8b84p-3,
-0x1.917a6cp-4};

// horner's algorithm to accurately and efficiently evaluate a degree-9
// polynomial iteratively
float horners(float x, const float COEFF[10]) {
float b8 = fputil::multiply_add<float>(COEFF[9], x, COEFF[8]);
float b7 = fputil::multiply_add<float>(b8, x, COEFF[7]);
float b6 = fputil::multiply_add<float>(b7, x, COEFF[6]);
float b5 = fputil::multiply_add<float>(b6, x, COEFF[5]);
float b4 = fputil::multiply_add<float>(b5, x, COEFF[4]);
float b3 = fputil::multiply_add<float>(b4, x, COEFF[3]);
float b2 = fputil::multiply_add<float>(b3, x, COEFF[2]);
float b1 = fputil::multiply_add<float>(b2, x, COEFF[1]);
return fputil::multiply_add<float>(b1, x, COEFF[0]);
}

float range_reduction(float x, float &y) {
const float SIN_K_PI_OVER_32[64] = {
0, 0x1.917a6cp-4,
0x1.8f8b84p-3, 0x1.294062p-2,
0x1.87de2ap-2, 0x1.e2b5d4p-2,
0x1.1c73b4p-1, 0x1.44cf32p-1,
0x1.6a09e6p-1, 0x1.8bc806p-1,
0x1.a9b662p-1, 0x1.c38b3p-1,
0x1.d906bcp-1, 0x1.e9f416p-1,
0x1.f6297cp-1, 0x1.fd88dap-1,
0x1p0, 0x1.fd88dap-1,
0x1.f6297cp-1, 0x1.e9f416p-1,
0x1.d906bcp-1, 0x1.c38b3p-1,
0x1.a9b662p-1, 0x1.8bc806p-1,
0x1.6a09e6p-1, 0x1.44cf32p-1,
0x1.1c73b4p-1, 0x1.e2b5d4p-2,
0x1.87de2ap-2, 0x1.294062p-2,
0x1.8f8b84p-3, 0x1.917a6cp-4,
0, -0x1.917a6cp-4,
-0x1.8f8b84p-3, -0x1.294062p-2,
-0x1.87de2ap-2, -0x1.e2b5d4p-2,
-0x1.1c73b4p-1, -0x1.44cf32p-1,
-0x1.6a09e6p-1, -0x1.8bc806p-1,
-0x1.a9b662p-1, -0x1.c38b3p-1,
-0x1.d906bcp-1, -0x1.e9f416p-1,
-0x1.f6297ep-1, -0x1.fd88dap-1,
-0x1p0, -0x1.fd88dap-1,
-0x1.f6297cp-1, -0x1.e9f416p-1,
-0x1.d906bcp-1, -0x1.c38b3p-1,
-0x1.a9b662p-1, -0x1.8bc806p-1,
-0x1.6a09e6p-1, -0x1.44cf32p-1,
-0x1.1c73b4p-1, -0x1.e2b5d4p-2,
-0x1.87de2ap-2, -0x1.294062p-2,
-0x1.8f8b84p-3, -0x1.917a6cp-4
};

int32_t range_reduction(float x, float &y) {
float kf = fputil::nearest_integer(x * 32);
y = fputil::multiply_add<float>(x, 32.0, -kf);

Expand Down Expand Up @@ -164,7 +120,28 @@ LLVM_LIBC_FUNCTION(float16, sinpif16, (float16 x)) {
// * pi/32) and cos(y * pi/32) are computed using degree-9 chebyshev
// polynomials generated by Sollya.

float f32 = x;
if (LIBC_UNLIKELY(x_abs == 0U)) {
// For signed zeros
return x;
}

// Numbers greater or equal to 2^10 are integers or NaN
if (LIBC_UNLIKELY(x_abs >= 0x6400)) {
// Check for NaN or infinity values
if (LIBC_UNLIKELY(x_abs >= 0x7c00)) {
// If value is equal to infinity
if (x_abs == 0x7c00) {
fputil::set_errno_if_required(EDOM);
fputil::raise_except_if_required(FE_INVALID);
}

// If value is NaN
return x + FPBits::quiet_nan().get_val();
}
return FPBits::zero(xbits.sign()).get_val();
}

float f32 = static_cast<float>(x);
float y;
int32_t k = range_reduction(f32, y);

Expand All @@ -176,11 +153,21 @@ LLVM_LIBC_FUNCTION(float16, sinpif16, (float16 x)) {
cos_y = 1;
sin_y = 0;
} else {
cos_y = horners(y * PI_OVER_32, COS_COEFF);
sin_y = horners(y * PI_OVER_32, SIN_COEFF);
cos_y = fputil::polyeval(y * PI_OVER_32,
COS_COEFF[0], COS_COEFF[1],
COS_COEFF[2], COS_COEFF[3],
COS_COEFF[4], COS_COEFF[5],
COS_COEFF[6], COS_COEFF[7],
COS_COEFF[8], COS_COEFF[9]);
sin_y = fputil::polyeval(y * PI_OVER_32,
SIN_COEFF[0], SIN_COEFF[1],
SIN_COEFF[2], SIN_COEFF[3],
SIN_COEFF[4], SIN_COEFF[5],
SIN_COEFF[6], SIN_COEFF[7],
SIN_COEFF[8], SIN_COEFF[9]);
}

return static_cast<float16>(fputil::multiply_add(
sin_k, cos_y, fputil::multiply_add(sin_y, cos_k, 0)));
sin_k, cos_y, fputil::multiply_add(sin_y, cos_k, 0.0f)));
}
} // namespace LIBC_NAMESPACE_DECL
12 changes: 6 additions & 6 deletions libc/test/src/math/smoke/sinpif16_test.cpp
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
//===-- Unittests for sinpif16 ------------------------------------===//
//===-- Unittests for sinpif16 --------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
Expand Down Expand Up @@ -30,15 +30,15 @@ TEST_F(LlvmLibcSinpif16Test, SpecialNumbers) {
EXPECT_FP_EQ(aNaN, LIBC_NAMESPACE::sinpif16(inf));
EXPECT_MATH_ERRNO(EDOM);

EXPECT_FP_EQ(aNan, LIBC_NAMESPACE::sinpif16(neg_inf));
EXPECT_FP_EQ(aNaN, LIBC_NAMESPACE::sinpif16(neg_inf));
EXPECT_MATH_ERRNO(EDOM);
}

TEST_F(LlvmLibcSinpif16Test, Integers) {
EXPECT_FP_EQ(-0.0, LIBC_NAMESPACE::sinpif16(-0x420));
EXPECT_FP_EQ(-0.0, LIBC_NAMESPACE::sinpif16(-0x1p+43));
EXPECT_FP_EQ(-0.0, LIBC_NAMESPACE::sinpif16(-0x1.4p+64));
EXPECT_FP_EQ(-0.0, LIBC_NAMESPACE::sinpif16(-0x1p+10));
EXPECT_FP_EQ(-0.0, LIBC_NAMESPACE::sinpif16(-0x1.4p+14));
EXPECT_FP_EQ(0.0, LIBC_NAMESPACE::sinpif16(0x420));
EXPECT_FP_EQ(0.0, LIBC_NAMESPACE::sinpif16(0x1.cp+106));
EXPECT_FP_EQ(0.0, LIBC_NAMESPACE::sinpif16(0x1.cp+21));
EXPECT_FP_EQ(0.0, LIBC_NAMESPACE::sinpif16(0x1.cp+15));
EXPECT_FP_EQ(0.0, LIBC_NAMESPACE::sinpif16(0x1.cp+7));
}
2 changes: 1 addition & 1 deletion libc/utils/MPFRWrapper/MPFRUtils.h
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Original file line number Diff line number Diff line change
Expand Up @@ -55,7 +55,7 @@ enum class Operation : int {
RoundEven,
Sin,
Sinpi,
Sinpif16 Sinh,
Sinh,
Sqrt,
Tan,
Tanh,
Expand Down
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