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[libc][math] Refactor asinhf implementation to header-only in src/__support/math folder. (#150843)

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Part of #147386

in preparation for: https://discourse.llvm.org/t/rfc-make-clang-builtin-math-functions-constexpr-with-llvm-libc-to-support-c-23-constexpr-math-functions/86450
This commit is contained in:
Muhammad Bassiouni 2025-07-28 18:14:47 +03:00 committed by GitHub
parent fbf6271c7d
commit 5bcbcf8d53
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GPG Key ID: B5690EEEBB952194
9 changed files with 183 additions and 118 deletions
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1
libc/shared/math.h
View File

@ -20,6 +20,7 @@
#include "math/asin.h"
#include "math/asinf.h"
#include "math/asinf16.h"
#include "math/asinhf.h"
#include "math/erff.h"
#include "math/exp.h"
#include "math/exp10.h"

23
libc/shared/math/asinhf.h Normal file
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@ -0,0 +1,23 @@
//===-- Shared asinhf function ----------------------------------*- 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_ASINHF_H
#define LLVM_LIBC_SHARED_MATH_ASINHF_H
#include "shared/libc_common.h"
#include "src/__support/math/asinhf.h"
namespace LIBC_NAMESPACE_DECL {
namespace shared {
using math::asinhf;
} // namespace shared
} // namespace LIBC_NAMESPACE_DECL
#endif // LLVM_LIBC_SHARED_MATH_ASINHF_H

14
libc/src/__support/math/CMakeLists.txt
View File

@ -140,6 +140,20 @@ add_header_library(
libc.src.__support.macros.properties.cpu_features
)
add_header_library(
asinhf
HDRS
asinhf.h
DEPENDS
.acoshf_utils
libc.src.__support.FPUtil.fp_bits
libc.src.__support.FPUtil.polyeval
libc.src.__support.FPUtil.multiply_add
libc.src.__support.FPUtil.sqrt
libc.src.__support.macros.config
libc.src.__support.macros.optimization
)
add_header_library(
asinf
HDRS

125
libc/src/__support/math/asinhf.h Normal file
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@ -0,0 +1,125 @@
//===-- Implementation header for asinf -------------------------*- 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_ASINHF_H
#define LLVM_LIBC_SRC___SUPPORT_MATH_ASINHF_H
#include "acoshf_utils.h"
#include "src/__support/FPUtil/FPBits.h"
#include "src/__support/FPUtil/PolyEval.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
namespace LIBC_NAMESPACE_DECL {
namespace math {
LIBC_INLINE static constexpr float asinhf(float x) {
using namespace acoshf_internal;
using FPBits_t = typename fputil::FPBits<float>;
FPBits_t xbits(x);
uint32_t x_u = xbits.uintval();
uint32_t x_abs = xbits.abs().uintval();
// |x| <= 2^-3
if (LIBC_UNLIKELY(x_abs <= 0x3e80'0000U)) {
// |x| <= 2^-26
if (LIBC_UNLIKELY(x_abs <= 0x3280'0000U)) {
return static_cast<float>(LIBC_UNLIKELY(x_abs == 0)
? x
: (x - 0x1.5555555555555p-3 * x * x * x));
}
double x_d = x;
double x_sq = x_d * x_d;
// Generated by Sollya with:
// > P = fpminimax(asinh(x)/x, [|0, 2, 4, 6, 8, 10, 12, 14, 16|], [|D...|],
// [0, 2^-2]);
double p = fputil::polyeval(
x_sq, 0.0, -0x1.555555555551ep-3, 0x1.3333333325495p-4,
-0x1.6db6db5a7622bp-5, 0x1.f1c70f82928c6p-6, -0x1.6e893934266b7p-6,
0x1.1c0b41d3fbe78p-6, -0x1.c0f47810b3c4fp-7, 0x1.2c8602690143dp-7);
return static_cast<float>(fputil::multiply_add(x_d, p, x_d));
}
const double SIGN[2] = {1.0, -1.0};
double x_sign = SIGN[x_u >> 31];
double x_d = x;
#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
// Helper functions to set results for exceptional cases.
auto round_result_slightly_down = [x_sign](float r) -> float {
return fputil::multiply_add(static_cast<float>(x_sign), r,
static_cast<float>(x_sign) * (-0x1.0p-24f));
};
auto round_result_slightly_up = [x_sign](float r) -> float {
return fputil::multiply_add(static_cast<float>(x_sign), r,
static_cast<float>(x_sign) * 0x1.0p-24f);
};
if (LIBC_UNLIKELY(x_abs >= 0x4bdd'65a5U)) {
if (LIBC_UNLIKELY(xbits.is_inf_or_nan())) {
if (xbits.is_signaling_nan()) {
fputil::raise_except_if_required(FE_INVALID);
return FPBits_t::quiet_nan().get_val();
}
return x;
}
// Exceptional cases when x > 2^24.
switch (x_abs) {
case 0x4bdd65a5: // |x| = 0x1.bacb4ap24f
return round_result_slightly_down(0x1.1e0696p4f);
case 0x4c803f2c: // |x| = 0x1.007e58p26f
return round_result_slightly_down(0x1.2b786cp4f);
case 0x4f8ffb03: // |x| = 0x1.1ff606p32f
return round_result_slightly_up(0x1.6fdd34p4f);
case 0x5c569e88: // |x| = 0x1.ad3d1p57f
return round_result_slightly_up(0x1.45c146p5f);
case 0x5e68984e: // |x| = 0x1.d1309cp61f
return round_result_slightly_up(0x1.5c9442p5f);
case 0x655890d3: // |x| = 0x1.b121a6p75f
return round_result_slightly_down(0x1.a9a3f2p5f);
case 0x65de7ca6: // |x| = 0x1.bcf94cp76f
return round_result_slightly_up(0x1.af66cp5f);
case 0x6eb1a8ec: // |x| = 0x1.6351d8p94f
return round_result_slightly_down(0x1.08b512p6f);
case 0x7997f30a: // |x| = 0x1.2fe614p116f
return round_result_slightly_up(0x1.451436p6f);
}
} else {
// Exceptional cases when x < 2^24.
if (LIBC_UNLIKELY(x_abs == 0x45abaf26)) {
// |x| = 0x1.575e4cp12f
return round_result_slightly_down(0x1.29becap3f);
}
if (LIBC_UNLIKELY(x_abs == 0x49d29048)) {
// |x| = 0x1.a5209p20f
return round_result_slightly_down(0x1.e1b92p3f);
}
}
#else
if (LIBC_UNLIKELY(xbits.is_inf_or_nan()))
return x;
#endif // !LIBC_MATH_HAS_SKIP_ACCURATE_PASS
// asinh(x) = log(x + sqrt(x^2 + 1))
return static_cast<float>(
x_sign * log_eval(fputil::multiply_add(
x_d, x_sign,
fputil::sqrt<double>(fputil::multiply_add(x_d, x_d, 1.0)))));
}
} // namespace math
} // namespace LIBC_NAMESPACE_DECL
#endif // LLVM_LIBC_SRC___SUPPORT_MATH_ASINHF_H

7
libc/src/math/generic/CMakeLists.txt
View File

@ -3889,12 +3889,7 @@ add_entrypoint_object(
HDRS
../asinhf.h
DEPENDS
.explogxf
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.math.asinhf
)
add_entrypoint_object(

106
libc/src/math/generic/asinhf.cpp
View File

@ -7,112 +7,10 @@
//===----------------------------------------------------------------------===//
#include "src/math/asinhf.h"
#include "src/__support/FPUtil/FPBits.h"
#include "src/__support/FPUtil/PolyEval.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/math/generic/common_constants.h"
#include "src/math/generic/explogxf.h"
#include "src/__support/math/asinhf.h"
namespace LIBC_NAMESPACE_DECL {
LLVM_LIBC_FUNCTION(float, asinhf, (float x)) {
using namespace acoshf_internal;
using FPBits_t = typename fputil::FPBits<float>;
FPBits_t xbits(x);
uint32_t x_u = xbits.uintval();
uint32_t x_abs = xbits.abs().uintval();
// |x| <= 2^-3
if (LIBC_UNLIKELY(x_abs <= 0x3e80'0000U)) {
// |x| <= 2^-26
if (LIBC_UNLIKELY(x_abs <= 0x3280'0000U)) {
return static_cast<float>(LIBC_UNLIKELY(x_abs == 0)
? x
: (x - 0x1.5555555555555p-3 * x * x * x));
}
double x_d = x;
double x_sq = x_d * x_d;
// Generated by Sollya with:
// > P = fpminimax(asinh(x)/x, [|0, 2, 4, 6, 8, 10, 12, 14, 16|], [|D...|],
// [0, 2^-2]);
double p = fputil::polyeval(
x_sq, 0.0, -0x1.555555555551ep-3, 0x1.3333333325495p-4,
-0x1.6db6db5a7622bp-5, 0x1.f1c70f82928c6p-6, -0x1.6e893934266b7p-6,
0x1.1c0b41d3fbe78p-6, -0x1.c0f47810b3c4fp-7, 0x1.2c8602690143dp-7);
return static_cast<float>(fputil::multiply_add(x_d, p, x_d));
}
const double SIGN[2] = {1.0, -1.0};
double x_sign = SIGN[x_u >> 31];
double x_d = x;
#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
// Helper functions to set results for exceptional cases.
auto round_result_slightly_down = [x_sign](float r) -> float {
return fputil::multiply_add(static_cast<float>(x_sign), r,
static_cast<float>(x_sign) * (-0x1.0p-24f));
};
auto round_result_slightly_up = [x_sign](float r) -> float {
return fputil::multiply_add(static_cast<float>(x_sign), r,
static_cast<float>(x_sign) * 0x1.0p-24f);
};
if (LIBC_UNLIKELY(x_abs >= 0x4bdd'65a5U)) {
if (LIBC_UNLIKELY(xbits.is_inf_or_nan())) {
if (xbits.is_signaling_nan()) {
fputil::raise_except_if_required(FE_INVALID);
return FPBits_t::quiet_nan().get_val();
}
return x;
}
// Exceptional cases when x > 2^24.
switch (x_abs) {
case 0x4bdd65a5: // |x| = 0x1.bacb4ap24f
return round_result_slightly_down(0x1.1e0696p4f);
case 0x4c803f2c: // |x| = 0x1.007e58p26f
return round_result_slightly_down(0x1.2b786cp4f);
case 0x4f8ffb03: // |x| = 0x1.1ff606p32f
return round_result_slightly_up(0x1.6fdd34p4f);
case 0x5c569e88: // |x| = 0x1.ad3d1p57f
return round_result_slightly_up(0x1.45c146p5f);
case 0x5e68984e: // |x| = 0x1.d1309cp61f
return round_result_slightly_up(0x1.5c9442p5f);
case 0x655890d3: // |x| = 0x1.b121a6p75f
return round_result_slightly_down(0x1.a9a3f2p5f);
case 0x65de7ca6: // |x| = 0x1.bcf94cp76f
return round_result_slightly_up(0x1.af66cp5f);
case 0x6eb1a8ec: // |x| = 0x1.6351d8p94f
return round_result_slightly_down(0x1.08b512p6f);
case 0x7997f30a: // |x| = 0x1.2fe614p116f
return round_result_slightly_up(0x1.451436p6f);
}
} else {
// Exceptional cases when x < 2^24.
if (LIBC_UNLIKELY(x_abs == 0x45abaf26)) {
// |x| = 0x1.575e4cp12f
return round_result_slightly_down(0x1.29becap3f);
}
if (LIBC_UNLIKELY(x_abs == 0x49d29048)) {
// |x| = 0x1.a5209p20f
return round_result_slightly_down(0x1.e1b92p3f);
}
}
#else
if (LIBC_UNLIKELY(xbits.is_inf_or_nan()))
return x;
#endif // !LIBC_MATH_HAS_SKIP_ACCURATE_PASS
// asinh(x) = log(x + sqrt(x^2 + 1))
return static_cast<float>(
x_sign * log_eval(fputil::multiply_add(
x_d, x_sign,
fputil::sqrt<double>(fputil::multiply_add(x_d, x_d, 1.0)))));
}
LLVM_LIBC_FUNCTION(float, asinhf, (float x)) { return math::asinhf(x); }
} // namespace LIBC_NAMESPACE_DECL

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

@ -16,6 +16,7 @@ add_fp_unittest(
libc.src.__support.math.asin
libc.src.__support.math.asinf
libc.src.__support.math.asinf16
libc.src.__support.math.asinhf
libc.src.__support.math.erff
libc.src.__support.math.exp
libc.src.__support.math.exp10

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

@ -42,6 +42,7 @@ TEST(LlvmLibcSharedMathTest, AllFloat) {
EXPECT_FP_EQ(0x1.921fb6p+0, LIBC_NAMESPACE::shared::acosf(0.0f));
EXPECT_FP_EQ(0x0p+0f, LIBC_NAMESPACE::shared::acoshf(1.0f));
EXPECT_FP_EQ(0x0p+0f, LIBC_NAMESPACE::shared::asinf(0.0f));
EXPECT_FP_EQ(0x0p+0f, LIBC_NAMESPACE::shared::asinhf(0.0f));
EXPECT_FP_EQ(0x0p+0f, LIBC_NAMESPACE::shared::erff(0.0f));
EXPECT_FP_EQ(0x1p+0f, LIBC_NAMESPACE::shared::exp10f(0.0f));
EXPECT_FP_EQ(0x1p+0f, LIBC_NAMESPACE::shared::expf(0.0f));

23
utils/bazel/llvm-project-overlay/libc/BUILD.bazel
View File

@ -2231,6 +2231,20 @@ libc_support_library(
],
)
libc_support_library(
name = "__support_math_asinhf",
hdrs = ["src/__support/math/asinhf.h"],
deps = [
":__support_math_acoshf_utils",
":__support_fputil_fp_bits",
":__support_fputil_polyeval",
":__support_fputil_multiply_add",
":__support_fputil_sqrt",
":__support_macros_config",
":__support_macros_optimization",
],
)
libc_support_library(
name = "__support_math_asinf",
hdrs = ["src/__support/math/asinf.h"],
@ -2829,14 +2843,7 @@ libc_math_function(
libc_math_function(
name = "asinhf",
additional_deps = [
":__support_fputil_fma",
":__support_fputil_multiply_add",
":__support_fputil_nearest_integer",
":__support_fputil_polyeval",
":__support_fputil_sqrt",
":__support_macros_optimization",
":common_constants",
":explogxf",
":__support_math_asinhf",
],
)