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[libc][math][c23] implement double-precision asinpi (#188158)

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Implement the double precision version of the asinpi c23 math function
This commit is contained in:
Mohamed Emad 2026-03-29 16:18:07 +02:00 committed by GitHub
parent 2e6e36b173
commit 1bb03026b6
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
29 changed files with 668 additions and 1 deletions
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1
libc/config/baremetal/aarch64/entrypoints.txt
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@ -349,6 +349,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.asin
libc.src.math.asinf
libc.src.math.asinhf
libc.src.math.asinpi
libc.src.math.asinpif
libc.src.math.atan2
libc.src.math.atan2f

1
libc/config/baremetal/arm/entrypoints.txt
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@ -359,6 +359,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.asin
libc.src.math.asinf
libc.src.math.asinhf
libc.src.math.asinpi
libc.src.math.asinpif
libc.src.math.atan2
libc.src.math.atan2f

1
libc/config/baremetal/riscv/entrypoints.txt
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@ -355,6 +355,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.acospif
libc.src.math.asinf
libc.src.math.asinhf
libc.src.math.asinpi
libc.src.math.asinpif
libc.src.math.atan2
libc.src.math.atan2f

1
libc/config/darwin/aarch64/entrypoints.txt
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@ -168,6 +168,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.asin
libc.src.math.asinf
libc.src.math.asinhf
libc.src.math.asinpi
libc.src.math.asinpif
libc.src.math.atan2
libc.src.math.atan2f

1
libc/config/gpu/amdgpu/entrypoints.txt
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@ -287,6 +287,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.asin
libc.src.math.asinf
libc.src.math.asinhf
libc.src.math.asinpi
libc.src.math.asinpif
libc.src.math.atan
libc.src.math.atan2

1
libc/config/gpu/nvptx/entrypoints.txt
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@ -287,6 +287,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.asin
libc.src.math.asinf
libc.src.math.asinhf
libc.src.math.asinpi
libc.src.math.asinpif
libc.src.math.atan
libc.src.math.atan2

1
libc/config/linux/aarch64/entrypoints.txt
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@ -443,6 +443,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.asin
libc.src.math.asinf
libc.src.math.asinhf
libc.src.math.asinpi
libc.src.math.asinpif
libc.src.math.atan2
libc.src.math.atan2f

1
libc/config/linux/arm/entrypoints.txt
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@ -268,6 +268,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.asin
libc.src.math.asinf
libc.src.math.asinhf
libc.src.math.asinpi
libc.src.math.asinpif
libc.src.math.atan2
libc.src.math.atan2f

1
libc/config/linux/riscv/entrypoints.txt
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@ -447,6 +447,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.asin
libc.src.math.asinf
libc.src.math.asinhf
libc.src.math.asinpi
libc.src.math.asinpif
libc.src.math.atan2
libc.src.math.atan2f

1
libc/config/linux/x86_64/entrypoints.txt
View File

@ -497,6 +497,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.asin
libc.src.math.asinf
libc.src.math.asinhf
libc.src.math.asinpi
libc.src.math.asinpif
libc.src.math.atan2
libc.src.math.atan2f

1
libc/config/windows/entrypoints.txt
View File

@ -148,6 +148,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.asin
libc.src.math.asinf
libc.src.math.asinhf
libc.src.math.asinpi
libc.src.math.asinpif
libc.src.math.atan2
libc.src.math.atan2f

2
libc/docs/headers/math/index.rst
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@ -269,7 +269,7 @@ Higher Math Functions
+-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+------------------------+----------------------------+
| asinh | |check| | | | |check| | | | 7.12.5.2 | F.10.2.2 |
+-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+------------------------+----------------------------+
| asinpi | |check| | | | |check| | | | 7.12.4.9 | F.10.1.9 |
| asinpi | |check| | |check| | | |check| | | | 7.12.4.9 | F.10.1.9 |
+-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+------------------------+----------------------------+
| atan | |check| | 1 ULP | | |check| | | |check| | 7.12.4.3 | F.10.1.3 |
+-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+------------------------+----------------------------+

12
libc/include/math.yaml
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@ -79,6 +79,18 @@ functions:
arguments:
- type: _Float16
guard: LIBC_TYPES_HAS_FLOAT16
- name: asinpi
standards:
- stdc
return_type: double
arguments:
- type: double
- name: asinpif
standards:
- stdc
return_type: float
arguments:
- type: float
- name: asinpif16
standards:
- stdc

1
libc/shared/math.h
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@ -23,6 +23,7 @@
#include "math/asinf16.h"
#include "math/asinhf.h"
#include "math/asinhf16.h"
#include "math/asinpi.h"
#include "math/asinpif.h"
#include "math/asinpif16.h"
#include "math/atan.h"

23
libc/shared/math/asinpi.h Normal file
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@ -0,0 +1,23 @@
//===-- Shared asinpi header ------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SHARED_MATH_ASINPI_H
#define LLVM_LIBC_SHARED_MATH_ASINPI_H
#include "shared/libc_common.h"
#include "src/__support/math/asinpi.h"
namespace LIBC_NAMESPACE_DECL {
namespace shared {
using math::asinpi;
} // namespace shared
} // namespace LIBC_NAMESPACE_DECL
#endif // LLVM_LIBC_SHARED_MATH_ASINPI_H

17
libc/src/__support/math/CMakeLists.txt
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@ -189,6 +189,23 @@ add_header_library(
libc.src.__support.macros.optimization
)
add_header_library(
asinpi
HDRS
asinpi.h
DEPENDS
.asin_utils
libc.src.__support.FPUtil.double_double
libc.src.__support.FPUtil.dyadic_float
libc.src.__support.FPUtil.fenv_impl
libc.src.__support.FPUtil.fp_bits
libc.src.__support.FPUtil.multiply_add
libc.src.__support.FPUtil.polyeval
libc.src.__support.FPUtil.sqrt
libc.src.__support.macros.optimization
libc.src.__support.macros.properties.cpu_features
)
add_header_library(
asinpif
HDRS

70
libc/src/__support/math/asin_utils.h
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@ -63,6 +63,47 @@ LIBC_INLINE double asin_eval(double u) {
return fputil::polyeval(u4, d0, d1, d2);
}
// Coefficients for the polynomial approximation of asin(x)/(pi*x) on [0, 0.5].
// Generated by Sollya:
// > prec = 200;
// > g = asin(x) / (pi * x);
// > P = fpminimax(g, [|0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22|],
// > [|D...|], [0, 0.5]);
// > print("Error:", dirtyinfnorm(P - g, [1e-30; 0.25]));
// Error : 0x1.a53f84eafa3ea69bb81b6c52b3278872083fca2c757bd778acp-54 ~= 2^-54
LIBC_INLINE_VAR constexpr double ASINPI_COEFFS[12] = {
0x1.45f306dc9c881p-2, // x^0
0x1.b2995e7b7e756p-5, // x^2
0x1.8723a1d12f828p-6, // x^4
0x1.d1a45564b9545p-7, // x^6
0x1.3ce4ceaa0e1e9p-7, // x^8
0x1.d2c305898ea13p-8, // x^10
0x1.692212e27a5f9p-8, // x^12
0x1.2b22cc744d25bp-8, // x^14
0x1.8427b864479ffp-9, // x^16
0x1.815522d7a2bf1p-8, // x^18
-0x1.f6df98438aef4p-9, // x^20
0x1.4b50c2eb13708p-7, // x^22
};
// Evaluate P(u) where P(u) ~ asin(sqrt(u))/(pi*sqrt(u)), using Estrin's scheme.
LIBC_INLINE double asinpi_eval(double u) {
double u2 = u * u;
double c0 = fputil::multiply_add(u, ASINPI_COEFFS[1], ASINPI_COEFFS[0]);
double c1 = fputil::multiply_add(u, ASINPI_COEFFS[3], ASINPI_COEFFS[2]);
double c2 = fputil::multiply_add(u, ASINPI_COEFFS[5], ASINPI_COEFFS[4]);
double c3 = fputil::multiply_add(u, ASINPI_COEFFS[7], ASINPI_COEFFS[6]);
double c4 = fputil::multiply_add(u, ASINPI_COEFFS[9], ASINPI_COEFFS[8]);
double c5 = fputil::multiply_add(u, ASINPI_COEFFS[11], ASINPI_COEFFS[10]);
double u4 = u2 * u2;
double d0 = fputil::multiply_add(u2, c1, c0);
double d1 = fputil::multiply_add(u2, c3, c2);
double d2 = fputil::multiply_add(u2, c5, c4);
return fputil::polyeval(u4, d0, d1, d2);
}
#else
// The Taylor expansion of asin(x) around 0 is:
@ -565,6 +606,35 @@ LIBC_INLINE constexpr Float128 asin_eval(const Float128 &u, unsigned idx) {
ASIN_COEFFS_F128[idx][14], ASIN_COEFFS_F128[idx][15]);
}
// 1/pi as DoubleDouble (~106 bits of precision).
LIBC_INLINE_VAR constexpr DoubleDouble ONE_OVER_PI_DD = {-0x1.6b01ec5417056p-56,
0x1.45f306dc9c883p-2};
// 1/pi as Float128 (~128 bits of precision).
LIBC_INLINE_VAR constexpr Float128 ONE_OVER_PI_F128 = {
Sign::POS, -129, 0xa2f9836e'4e441529'fc2757d1'f534ddc0_u128};
// 0.5 as Float128 (exact).
LIBC_INLINE_VAR constexpr Float128 HALF_F128 = {
Sign::POS, -128, 0x80000000'00000000'00000000'00000000_u128};
// Compute asin(sqrt(u))/(pi*sqrt(u)) in DoubleDouble precision by wrapping
// asin_eval and multiplying by 1/pi.
LIBC_INLINE DoubleDouble asinpi_eval(const DoubleDouble &u, unsigned &idx,
double &err) {
DoubleDouble p = asin_eval(u, idx, err);
DoubleDouble result = fputil::quick_mult(p, ONE_OVER_PI_DD);
// Scale error by ~1/pi and add multiplication rounding error.
err = err * 0x1.46p-2 + 0x1.0p-98;
return result;
}
// Compute asin(sqrt(u))/(pi*sqrt(u)) in Float128 precision.
LIBC_INLINE constexpr Float128 asinpi_eval(const Float128 &u, unsigned idx) {
Float128 p = asin_eval(u, idx);
return fputil::quick_mul(p, ONE_OVER_PI_F128);
}
#endif // LIBC_MATH_HAS_SKIP_ACCURATE_PASS
} // namespace asin_internal

291
libc/src/__support/math/asinpi.h Normal file
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@ -0,0 +1,291 @@
//===-- Implementation header for asinpi ------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC___SUPPORT_MATH_ASINPI_H
#define LLVM_LIBC_SRC___SUPPORT_MATH_ASINPI_H
#include "asin_utils.h"
#include "src/__support/FPUtil/FEnvImpl.h"
#include "src/__support/FPUtil/FPBits.h"
#include "src/__support/FPUtil/double_double.h"
#include "src/__support/FPUtil/dyadic_float.h"
#include "src/__support/FPUtil/multiply_add.h"
#include "src/__support/FPUtil/sqrt.h"
#include "src/__support/macros/config.h"
#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
#include "src/__support/macros/properties/cpu_features.h" // LIBC_TARGET_CPU_HAS_FMA
#include "src/__support/math/asin_utils.h"
namespace LIBC_NAMESPACE_DECL {
namespace math {
LIBC_INLINE double asinpi(double x) {
using namespace asin_internal;
using FPBits = fputil::FPBits<double>;
FPBits xbits(x);
int x_exp = xbits.get_biased_exponent();
// |x| < 0.5.
if (x_exp < FPBits::EXP_BIAS - 1) {
// |x| < 2^-26.
if (LIBC_UNLIKELY(x_exp < FPBits::EXP_BIAS - 26)) {
// asinpi(+-0) = +-0.
if (LIBC_UNLIKELY(xbits.abs().uintval() == 0))
return x;
// When |x| < 2^-26, asinpi(x) ~ x/pi.
// The relative error of x/pi is:
// |asinpi(x) - x/pi| / |asinpi(x)| < x^2/6 < 2^-54.
#ifdef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
return x * ASINPI_COEFFS[0];
#endif // LIBC_MATH_HAS_SKIP_ACCURATE_PASS
}
#ifdef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
return x * asinpi_eval(x * x);
#else
using Float128 = fputil::DyadicFloat<128>;
using DoubleDouble = fputil::DoubleDouble;
// For |x| < 2^-511, x^2 would underflow to subnormal, raising a
// spurious underflow exception. Since asinpi(x) = x/pi with correction
// x^2/(6*pi) < 2^-1024 relative (negligible), compute x/pi directly
// in Float128.
if (LIBC_UNLIKELY(x_exp < 512)) {
Float128 x_f128(x);
Float128 r = fputil::quick_mul(x_f128, ONE_OVER_PI_F128);
double result = static_cast<double>(r);
// IEEE 754 "after rounding" tininess: the 53-bit unlimited-exponent
// result is strictly between +-2^-1022. DyadicFloat's conversion
// checks the *IEEE subnormal* result (52-bit at the boundary), not
// the 53-bit unlimited-exponent result, so we detect it here.
int exp_hi = r.exponent + 127 + FPBits::EXP_BIAS;
if (LIBC_UNLIKELY(exp_hi <= 0) && !r.mantissa.is_zero()) {
bool raise_underflow = true;
// When exp_hi == 0, a carry in 53-bit rounding can push the
// result to exactly 2^-1022 (not tiny). Check for this.
if (exp_hi == 0) {
constexpr unsigned SHIFT_53 = 128 - FPBits::SIG_LEN - 1;
using MantT = typename Float128::MantissaType;
MantT m53 = r.mantissa >> SHIFT_53;
constexpr MantT ALL_ONES_53 = (MantT(1) << (FPBits::SIG_LEN + 1)) - 1;
if (m53 == ALL_ONES_53) {
// All 53 bits set. carry happens if rounding rounds away
// from zero at this precision.
bool round_bit =
static_cast<bool>((r.mantissa >> (SHIFT_53 - 1)) & 1);
MantT sticky_mask = (MantT(1) << (SHIFT_53 - 1)) - 1;
bool sticky = (r.mantissa & sticky_mask) != 0;
bool lsb = static_cast<bool>(m53 & 1);
switch (fputil::quick_get_round()) {
case FE_TONEAREST:
// Carry if round_bit && (lsb || sticky) (round half to even).
raise_underflow = !(round_bit && (lsb || sticky));
break;
case FE_UPWARD:
raise_underflow = xbits.is_neg() || !(round_bit || sticky);
break;
case FE_DOWNWARD:
raise_underflow = !xbits.is_neg() || !(round_bit || sticky);
break;
case FE_TOWARDZERO:
default:
raise_underflow = true; // truncation never carries
break;
}
}
}
if (raise_underflow)
fputil::raise_except_if_required(FE_UNDERFLOW | FE_INEXACT);
}
return result;
}
unsigned idx = 0;
DoubleDouble x_sq = fputil::exact_mult(x, x);
double err = xbits.abs().get_val() * 0x1.0p-51;
// Polynomial approximation:
// p ~ asin(x)/(pi*x)
DoubleDouble p = asinpi_eval(x_sq, idx, err);
// asinpi(x) ~ x * p
DoubleDouble r0 = fputil::exact_mult(x, p.hi);
double r_lo = fputil::multiply_add(x, p.lo, r0.lo);
// Ziv's accuracy test.
double r_upper = r0.hi + (r_lo + err);
double r_lower = r0.hi + (r_lo - err);
if (LIBC_LIKELY(r_upper == r_lower))
return r_upper;
// Ziv's accuracy test failed, perform 128-bit calculation.
// Recalculate mod 1/64.
idx = static_cast<unsigned>(fputil::nearest_integer(x_sq.hi * 0x1.0p6));
Float128 x_f128(x);
#ifdef LIBC_TARGET_CPU_HAS_FMA_DOUBLE
Float128 u_hi(
fputil::multiply_add(static_cast<double>(idx), -0x1.0p-6, x_sq.hi));
Float128 u = fputil::quick_add(u_hi, Float128(x_sq.lo));
#else
Float128 x_sq_f128 = fputil::quick_mul(x_f128, x_f128);
Float128 u = fputil::quick_add(
x_sq_f128, Float128(static_cast<double>(idx) * (-0x1.0p-6)));
#endif // LIBC_TARGET_CPU_HAS_FMA_DOUBLE
Float128 p_f128 = asinpi_eval(u, idx);
Float128 r = fputil::quick_mul(x_f128, p_f128);
return static_cast<double>(r);
#endif // LIBC_MATH_HAS_SKIP_ACCURATE_PASS
}
// |x| >= 0.5
double x_abs = xbits.abs().get_val();
// Maintaining the sign:
constexpr double SIGN[2] = {1.0, -1.0};
double x_sign = SIGN[xbits.is_neg()];
// |x| >= 1
if (LIBC_UNLIKELY(x_exp >= FPBits::EXP_BIAS)) {
// x = +-1, asinpi(x) = +- 0.5
if (x_abs == 1.0) {
return x_sign * 0.5;
}
// |x| > 1, return NaN.
if (xbits.is_quiet_nan())
return x;
// Set domain error for non-NaN input.
if (!xbits.is_nan())
fputil::set_errno_if_required(EDOM);
fputil::raise_except_if_required(FE_INVALID);
return FPBits::quiet_nan().get_val();
}
// When |x| >= 0.5, we perform range reduction as follow:
//
// Assume further that 0.5 <= x < 1, and let:
// y = asin(x)
// Using the identity:
// asin(x) = pi/2 - 2 * asin( sqrt( (1 - x)/2 ) )
// We get:
// asinpi(x) = asin(x)/pi = 0.5 - 2 * asin(sqrt(u)) / pi
// = 0.5 - 2 * sqrt(u) * [asin(sqrt(u)) / (pi * sqrt(u))]
// = 0.5 - 2 * sqrt(u) * asinpi_eval(u)
// where u = (1 - |x|) / 2.
// u = (1 - |x|)/2
double u = fputil::multiply_add(x_abs, -0.5, 0.5);
// v_hi ~ sqrt(u).
double v_hi = fputil::sqrt<double>(u);
#ifdef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
double p = asinpi_eval(u);
double r = x_sign * fputil::multiply_add(-2.0 * v_hi, p, 0.5);
return r;
#else
using Float128 = fputil::DyadicFloat<128>;
using DoubleDouble = fputil::DoubleDouble;
#ifdef LIBC_TARGET_CPU_HAS_FMA_DOUBLE
double h = fputil::multiply_add(v_hi, -v_hi, u);
#else
DoubleDouble v_hi_sq = fputil::exact_mult(v_hi, v_hi);
double h = (u - v_hi_sq.hi) - v_hi_sq.lo;
#endif // LIBC_TARGET_CPU_HAS_FMA_DOUBLE
// Scale v_lo and v_hi by 2 from the formula:
// vh = v_hi * 2
// vl = 2*v_lo = h / v_hi.
double vh = v_hi * 2.0;
double vl = h / v_hi;
// Polynomial approximation:
// p ~ asin(sqrt(u))/(pi*sqrt(u))
unsigned idx = 0;
double err = vh * 0x1.0p-51;
DoubleDouble p = asinpi_eval(DoubleDouble{0.0, u}, idx, err);
// Perform computations in double-double arithmetic:
// asinpi(x) = 0.5 - (vh + vl) * p
DoubleDouble r0 = fputil::quick_mult(DoubleDouble{vl, vh}, p);
DoubleDouble r = fputil::exact_add(0.5, -r0.hi);
double r_lo = -r0.lo + r.lo;
// Ziv's accuracy test.
#ifdef LIBC_TARGET_CPU_HAS_FMA_DOUBLE
double r_upper = fputil::multiply_add(
r.hi, x_sign, fputil::multiply_add(r_lo, x_sign, err));
double r_lower = fputil::multiply_add(
r.hi, x_sign, fputil::multiply_add(r_lo, x_sign, -err));
#else
r_lo *= x_sign;
r.hi *= x_sign;
double r_upper = r.hi + (r_lo + err);
double r_lower = r.hi + (r_lo - err);
#endif // LIBC_TARGET_CPU_HAS_FMA_DOUBLE
if (LIBC_LIKELY(r_upper == r_lower))
return r_upper;
// Ziv's accuracy test failed, we redo the computations in Float128.
// Recalculate mod 1/64.
idx = static_cast<unsigned>(fputil::nearest_integer(u * 0x1.0p6));
// After the first step of Newton-Raphson approximating v = sqrt(u):
// sqrt(u) = v_hi + h / (sqrt(u) + v_hi)
// v_lo = h / (2 * v_hi)
// Add second-order correction:
// v_ll = -v_lo * (h / (4u))
// Get the rounding error of vl = 2 * v_lo ~ h / vh
#ifdef LIBC_TARGET_CPU_HAS_FMA_DOUBLE
double vl_lo = fputil::multiply_add(-v_hi, vl, h) / v_hi;
#else
DoubleDouble vh_vl = fputil::exact_mult(v_hi, vl);
double vl_lo = ((h - vh_vl.hi) - vh_vl.lo) / v_hi;
#endif // LIBC_TARGET_CPU_HAS_FMA_DOUBLE
// vll = 2*v_ll = -vl * (h / (4u)).
double t = h * (-0.25) / u;
double vll = fputil::multiply_add(vl, t, vl_lo);
// m_v = -(v_hi + v_lo + v_ll).
Float128 m_v = fputil::quick_add(
Float128(vh), fputil::quick_add(Float128(vl), Float128(vll)));
m_v.sign = Sign::NEG;
// Perform computations in Float128:
// asinpi(x) = 0.5 - (v_hi + v_lo + vll) * P_pi(u).
Float128 y_f128(fputil::multiply_add(static_cast<double>(idx), -0x1.0p-6, u));
Float128 p_f128 = asinpi_eval(y_f128, idx);
Float128 r0_f128 = fputil::quick_mul(m_v, p_f128);
Float128 r_f128 = fputil::quick_add(HALF_F128, r0_f128);
if (xbits.is_neg())
r_f128.sign = Sign::NEG;
return static_cast<double>(r_f128);
#endif // LIBC_MATH_HAS_SKIP_ACCURATE_PASS
}
} // namespace math
} // namespace LIBC_NAMESPACE_DECL
#endif // LLVM_LIBC_SRC___SUPPORT_MATH_ASINPI_H

1
libc/src/math/CMakeLists.txt
View File

@ -59,6 +59,7 @@ add_math_entrypoint_object(asinh)
add_math_entrypoint_object(asinhf)
add_math_entrypoint_object(asinhf16)
add_math_entrypoint_object(asinpi)
add_math_entrypoint_object(asinpif)
add_math_entrypoint_object(asinpif16)

20
libc/src/math/asinpi.h Normal file
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@ -0,0 +1,20 @@
//===-- Implementation header for asinpi ------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC_MATH_ASINPI_H
#define LLVM_LIBC_SRC_MATH_ASINPI_H
#include "src/__support/macros/config.h"
namespace LIBC_NAMESPACE_DECL {
double asinpi(double x);
} // namespace LIBC_NAMESPACE_DECL
#endif // LLVM_LIBC_SRC_MATH_ASINPI_H

10
libc/src/math/generic/CMakeLists.txt
View File

@ -4037,6 +4037,16 @@ add_entrypoint_object(
libc.src.__support.math.asinhf16
)
add_entrypoint_object(
asinpi
SRCS
asinpi.cpp
HDRS
../asinpi.h
DEPENDS
libc.src.__support.math.asinpi
)
add_entrypoint_object(
asinpif
SRCS

16
libc/src/math/generic/asinpi.cpp Normal file
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@ -0,0 +1,16 @@
//===-- Double-precision asinpi function ----------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "src/math/asinpi.h"
#include "src/__support/math/asinpi.h"
namespace LIBC_NAMESPACE_DECL {
LLVM_LIBC_FUNCTION(double, asinpi, (double x)) { return math::asinpi(x); }
} // namespace LIBC_NAMESPACE_DECL

1
libc/test/shared/CMakeLists.txt
View File

@ -20,6 +20,7 @@ add_fp_unittest(
libc.src.__support.math.asinf16
libc.src.__support.math.asinhf
libc.src.__support.math.asinhf16
libc.src.__support.math.asinpi
libc.src.__support.math.asinpif
libc.src.__support.math.asinpif16
libc.src.__support.math.atan

1
libc/test/shared/shared_math_test.cpp
View File

@ -242,6 +242,7 @@ TEST(LlvmLibcSharedMathTest, AllDouble) {
EXPECT_FP_EQ(0x1.921fb54442d18p+0, LIBC_NAMESPACE::shared::acos(0.0));
EXPECT_FP_EQ(0x0p+0, LIBC_NAMESPACE::shared::asin(0.0));
EXPECT_FP_EQ(0x0p+0, LIBC_NAMESPACE::shared::asinpi(0.0));
EXPECT_FP_EQ(0x0p+0, LIBC_NAMESPACE::shared::atan(0.0));
EXPECT_FP_EQ(0x0p+0, LIBC_NAMESPACE::shared::atan2(0.0, 0.0));
EXPECT_FP_EQ(0x0p+0, LIBC_NAMESPACE::shared::cbrt(0.0));

11
libc/test/src/math/CMakeLists.txt
View File

@ -2523,6 +2523,17 @@ add_fp_unittest(
libc.src.math.asinf16
)
add_fp_unittest(
asinpi_test
NEED_MPFR
SUITE
libc-math-unittests
SRCS
asinpi_test.cpp
DEPENDS
libc.src.math.asinpi
)
add_fp_unittest(
asinpif_test
NEED_MPFR

92
libc/test/src/math/asinpi_test.cpp Normal file
View File

@ -0,0 +1,92 @@
//===-- Unittests for asinpi ----------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "src/__support/macros/optimization.h"
#include "src/math/asinpi.h"
#include "test/UnitTest/FPMatcher.h"
#include "test/UnitTest/Test.h"
#include "utils/MPFRWrapper/MPFRUtils.h"
#ifdef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
#define TOLERANCE 6
#else
#define TOLERANCE 0
#endif // LIBC_MATH_HAS_SKIP_ACCURATE_PASS
using LlvmLibcAsinpiTest = LIBC_NAMESPACE::testing::FPTest<double>;
namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
using LIBC_NAMESPACE::testing::tlog;
TEST_F(LlvmLibcAsinpiTest, InDoubleRange) {
constexpr uint64_t COUNT = 123'451;
uint64_t START = FPBits(0x1.0p-60).uintval();
uint64_t STOP = FPBits(1.0).uintval();
uint64_t STEP = (STOP - START) / COUNT;
auto test = [&](mpfr::RoundingMode rounding_mode) {
mpfr::ForceRoundingMode __r(rounding_mode);
if (!__r.success)
return;
uint64_t fails = 0;
uint64_t count = 0;
uint64_t cc = 0;
double mx = 0.0, mr = 0.0;
double tol = 0.5;
for (uint64_t i = 0, v = START; i <= COUNT; ++i, v += STEP) {
double x = FPBits(v).get_val();
if (FPBits(v).is_nan() || FPBits(v).is_inf())
continue;
libc_errno = 0;
double result = LIBC_NAMESPACE::asinpi(x);
++cc;
if (FPBits(result).is_nan() || FPBits(result).is_inf())
continue;
++count;
if (!TEST_MPFR_MATCH_ROUNDING_SILENTLY(mpfr::Operation::Asinpi, x, result,
TOLERANCE + 0.5, rounding_mode)) {
++fails;
while (!TEST_MPFR_MATCH_ROUNDING_SILENTLY(mpfr::Operation::Asinpi, x,
result, tol, rounding_mode)) {
mx = x;
mr = result;
if (tol > 1000.0)
break;
tol *= 2.0;
}
}
}
if (fails) {
tlog << " Asinpi failed: " << fails << "/" << count << "/" << cc
<< " tests.\n";
tlog << " Max ULPs is at most: " << static_cast<uint64_t>(tol) << ".\n";
EXPECT_MPFR_MATCH(mpfr::Operation::Asinpi, mx, mr, 0.5, rounding_mode);
}
};
tlog << " Test Rounding To Nearest...\n";
test(mpfr::RoundingMode::Nearest);
#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
tlog << " Test Rounding Downward...\n";
test(mpfr::RoundingMode::Downward);
tlog << " Test Rounding Upward...\n";
test(mpfr::RoundingMode::Upward);
tlog << " Test Rounding Toward Zero...\n";
test(mpfr::RoundingMode::TowardZero);
#endif // LIBC_MATH_HAS_SKIP_ACCURATE_PASS
}

12
libc/test/src/math/smoke/CMakeLists.txt
View File

@ -4757,6 +4757,18 @@ add_fp_unittest(
libc.src.math.asinhf16
)
add_fp_unittest(
asinpi_test
SUITE
libc-math-smoke-tests
SRCS
asinpi_test.cpp
DEPENDS
libc.hdr.fenv_macros
libc.src.math.asinpi
libc.src.__support.FPUtil.fp_bits
)
add_fp_unittest(
asinpif_test
SUITE

52
libc/test/src/math/smoke/asinpi_test.cpp Normal file
View File

@ -0,0 +1,52 @@
//===-- Unittests for asinpi ----------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "hdr/fenv_macros.h"
#include "src/math/asinpi.h"
#include "test/UnitTest/FPMatcher.h"
#include "test/UnitTest/Test.h"
using LlvmLibcAsinpiTest = LIBC_NAMESPACE::testing::FPTest<double>;
TEST_F(LlvmLibcAsinpiTest, SpecialNumbers) {
EXPECT_FP_EQ_WITH_EXCEPTION_ALL_ROUNDING(aNaN, LIBC_NAMESPACE::asinpi(sNaN),
FE_INVALID);
EXPECT_FP_EQ_ALL_ROUNDING(aNaN, LIBC_NAMESPACE::asinpi(aNaN));
EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::asinpi(zero));
EXPECT_FP_EQ_ALL_ROUNDING(neg_zero, LIBC_NAMESPACE::asinpi(neg_zero));
EXPECT_FP_EQ_ALL_ROUNDING(aNaN, LIBC_NAMESPACE::asinpi(inf));
EXPECT_FP_EQ_ALL_ROUNDING(aNaN, LIBC_NAMESPACE::asinpi(neg_inf));
EXPECT_FP_EQ_ALL_ROUNDING(aNaN, LIBC_NAMESPACE::asinpi(2.0));
EXPECT_FP_EQ_ALL_ROUNDING(aNaN, LIBC_NAMESPACE::asinpi(-2.0));
EXPECT_FP_EQ(0.5, LIBC_NAMESPACE::asinpi(1.0));
EXPECT_FP_EQ(-0.5, LIBC_NAMESPACE::asinpi(-1.0));
}
#ifdef LIBC_TEST_FTZ_DAZ
using namespace LIBC_NAMESPACE::testing;
TEST_F(LlvmLibcAsinpiTest, FTZMode) {
ModifyMXCSR mxcsr(FTZ);
EXPECT_TRUE(zero == LIBC_NAMESPACE::asinpi(min_denormal));
}
TEST_F(LlvmLibcAsinpiTest, DAZMode) {
ModifyMXCSR mxcsr(DAZ);
EXPECT_TRUE(zero == LIBC_NAMESPACE::asinpi(min_denormal));
}
TEST_F(LlvmLibcAsinpiTest, FTZDAZMode) {
ModifyMXCSR mxcsr(FTZ | DAZ);
EXPECT_TRUE(zero == LIBC_NAMESPACE::asinpi(min_denormal));
}
#endif

26
utils/bazel/llvm-project-overlay/libc/BUILD.bazel
View File

@ -3189,6 +3189,25 @@ libc_support_library(
],
)
libc_support_library(
name = "__support_math_asinpi",
hdrs = ["src/__support/math/asinpi.h"],
deps = [
":__support_fputil_cast",
":__support_fputil_double_double",
":__support_fputil_except_value_utils",
":__support_fputil_fenv_impl",
":__support_fputil_fp_bits",
":__support_fputil_multiply_add",
":__support_fputil_polyeval",
":__support_fputil_rounding_mode",
":__support_fputil_sqrt",
":__support_macros_config",
":__support_macros_optimization",
":__support_math_asin_utils",
],
)
libc_support_library(
name = "__support_math_asinpif",
hdrs = ["src/__support/math/asinpif.h"],
@ -6566,6 +6585,13 @@ libc_math_function(
],
)
libc_math_function(
name = "asinpi",
additional_deps = [
":__support_math_asinpi",
],
)
libc_math_function(
name = "asinpif",
additional_deps = [