[libc][math] Refactor acoshf16 implementation to header-only in src/__support/math folder. #148568
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✅ With the latest revision this PR passed the C/C++ code formatter. |
…_support/math folder.
|
@llvm/pr-subscribers-libc Author: Muhammad Bassiouni (bassiounix) ChangesPart 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 Please merge #148418 first Full diff: https://github.com/llvm/llvm-project/pull/148568.diff 9 Files Affected:
diff --git a/libc/shared/math.h b/libc/shared/math.h
index 33fe235c51824..e3c674c27ffaf 100644
--- a/libc/shared/math.h
+++ b/libc/shared/math.h
@@ -15,6 +15,7 @@
#include "math/acosf.h"
#include "math/acosf16.h"
#include "math/acoshf.h"
+#include "math/acoshf16.h"
#include "math/erff.h"
#include "math/exp.h"
#include "math/exp10.h"
diff --git a/libc/shared/math/acoshf16.h b/libc/shared/math/acoshf16.h
new file mode 100644
index 0000000000000..2f0bc6e80ab6d
--- /dev/null
+++ b/libc/shared/math/acoshf16.h
@@ -0,0 +1,29 @@
+//===-- Shared acoshf16 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_ACOSHF16_H
+#define LLVM_LIBC_SHARED_MATH_ACOSHF16_H
+
+#include "include/llvm-libc-macros/float16-macros.h"
+#include "shared/libc_common.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT16
+
+#include "src/__support/math/acoshf16.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::acoshf16;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT16
+
+#endif // LLVM_LIBC_SHARED_MATH_ACOSHF16_H
diff --git a/libc/src/__support/math/CMakeLists.txt b/libc/src/__support/math/CMakeLists.txt
index b0e562fb20d0d..9a8a4d16a4a0e 100644
--- a/libc/src/__support/math/CMakeLists.txt
+++ b/libc/src/__support/math/CMakeLists.txt
@@ -79,6 +79,22 @@ add_header_library(
libc.src.__support.macros.optimization
)
+add_header_library(
+ acoshf16
+ HDRS
+ acoshf16.h
+ DEPENDS
+ .acoshf_utils
+ libc.src.__support.FPUtil.cast
+ libc.src.__support.FPUtil.except_value_utils
+ 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
+)
+
add_header_library(
asin_utils
HDRS
diff --git a/libc/src/__support/math/acoshf16.h b/libc/src/__support/math/acoshf16.h
new file mode 100644
index 0000000000000..15e7f6ae7e208
--- /dev/null
+++ b/libc/src/__support/math/acoshf16.h
@@ -0,0 +1,123 @@
+//===-- Implementation header for acoshf16 ----------------------*- 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_ACOSHF_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_ACOSHF_H
+
+#include "include/llvm-libc-macros/float16-macros.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT16
+
+#include "acoshf_utils.h"
+#include "src/__support/FPUtil/FEnvImpl.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/FPUtil/PolyEval.h"
+#include "src/__support/FPUtil/cast.h"
+#include "src/__support/FPUtil/except_value_utils.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"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace math {
+
+static constexpr float16 acoshf16(float16 x) {
+
+ using namespace acoshf_internal;
+ constexpr size_t N_EXCEPTS = 2;
+ constexpr fputil::ExceptValues<float16, N_EXCEPTS> ACOSHF16_EXCEPTS{{
+ // (input, RZ output, RU offset, RD offset, RN offset)
+ // x = 0x1.6dcp+1, acoshf16(x) = 0x1.b6p+0 (RZ)
+ {0x41B7, 0x3ED8, 1, 0, 0},
+ // x = 0x1.39p+0, acoshf16(x) = 0x1.4f8p-1 (RZ)
+ {0x3CE4, 0x393E, 1, 0, 1},
+ }};
+
+ using FPBits = fputil::FPBits<float16>;
+ FPBits xbits(x);
+ uint16_t x_u = xbits.uintval();
+
+ // Check for NaN input first.
+ if (LIBC_UNLIKELY(xbits.is_inf_or_nan())) {
+ if (xbits.is_signaling_nan()) {
+ fputil::raise_except_if_required(FE_INVALID);
+ return FPBits::quiet_nan().get_val();
+ }
+ if (xbits.is_neg()) {
+ fputil::set_errno_if_required(EDOM);
+ fputil::raise_except_if_required(FE_INVALID);
+ return FPBits::quiet_nan().get_val();
+ }
+ return x;
+ }
+
+ // Domain error for inputs less than 1.0.
+ if (LIBC_UNLIKELY(x <= 1.0f)) {
+ if (x == 1.0f)
+ return FPBits::zero().get_val();
+ fputil::set_errno_if_required(EDOM);
+ fputil::raise_except_if_required(FE_INVALID);
+ return FPBits::quiet_nan().get_val();
+ }
+
+ if (auto r = ACOSHF16_EXCEPTS.lookup(xbits.uintval());
+ LIBC_UNLIKELY(r.has_value()))
+ return r.value();
+
+ float xf = x;
+ // High-precision polynomial approximation for inputs close to 1.0
+ // ([1, 1.25)).
+ //
+ // Brief derivation:
+ // 1. Expand acosh(1 + delta) using Taylor series around delta=0:
+ // acosh(1 + delta) ≈ sqrt(2 * delta) * [1 - delta/12 + 3*delta^2/160
+ // - 5*delta^3/896 + 35*delta^4/18432 + ...]
+ // 2. Truncate the series to fit accurately for delta in [0, 0.25].
+ // 3. Polynomial coefficients (from sollya) used here are:
+ // P(delta) ≈ 1 - 0x1.555556p-4 * delta + 0x1.333334p-6 * delta^2
+ // - 0x1.6db6dcp-8 * delta^3 + 0x1.f1c71cp-10 * delta^4
+ // 4. The Sollya commands used to generate these coefficients were:
+ // > display = hexadecimal;
+ // > round(1/12, SG, RN);
+ // > round(3/160, SG, RN);
+ // > round(5/896, SG, RN);
+ // > round(35/18432, SG, RN);
+ // With hexadecimal display mode enabled, the outputs were:
+ // 0x1.555556p-4
+ // 0x1.333334p-6
+ // 0x1.6db6dcp-8
+ // 0x1.f1c71cp-10
+ // 5. The maximum absolute error, estimated using:
+ // dirtyinfnorm(acosh(1 + x) - sqrt(2*x) * P(x), [0, 0.25])
+ // is:
+ // 0x1.d84281p-22
+ if (LIBC_UNLIKELY(x_u < 0x3D00U)) {
+ float delta = xf - 1.0f;
+ float sqrt_2_delta = fputil::sqrt<float>(2.0 * delta);
+ float pe = fputil::polyeval(delta, 0x1p+0f, -0x1.555556p-4f, 0x1.333334p-6f,
+ -0x1.6db6dcp-8f, 0x1.f1c71cp-10f);
+ float approx = sqrt_2_delta * pe;
+ return fputil::cast<float16>(approx);
+ }
+
+ // acosh(x) = log(x + sqrt(x^2 - 1))
+ float sqrt_term = fputil::sqrt<float>(fputil::multiply_add(xf, xf, -1.0f));
+ float result = static_cast<float>(log_eval(xf + sqrt_term));
+
+ return fputil::cast<float16>(result);
+}
+
+} // namespace math
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT16
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_ACOSHF_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 86baf2b981bb2..408f99ef30760 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -3878,18 +3878,8 @@ add_entrypoint_object(
HDRS
../acoshf16.h
DEPENDS
- .explogxf
- libc.hdr.errno_macros
- libc.hdr.fenv_macros
- libc.src.__support.FPUtil.cast
- libc.src.__support.FPUtil.except_value_utils
- 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.types
+ libc.src.__support.math.acoshf16
+ libc.src.errno.errno
)
add_entrypoint_object(
diff --git a/libc/src/math/generic/acoshf16.cpp b/libc/src/math/generic/acoshf16.cpp
index 96ca956c82147..bb3a91f707080 100644
--- a/libc/src/math/generic/acoshf16.cpp
+++ b/libc/src/math/generic/acoshf16.cpp
@@ -7,105 +7,10 @@
//===----------------------------------------------------------------------===//
#include "src/math/acoshf16.h"
-#include "explogxf.h"
-#include "hdr/errno_macros.h"
-#include "hdr/fenv_macros.h"
-#include "src/__support/FPUtil/FEnvImpl.h"
-#include "src/__support/FPUtil/FPBits.h"
-#include "src/__support/FPUtil/PolyEval.h"
-#include "src/__support/FPUtil/cast.h"
-#include "src/__support/FPUtil/except_value_utils.h"
-#include "src/__support/FPUtil/multiply_add.h"
-#include "src/__support/FPUtil/sqrt.h"
-#include "src/__support/common.h"
-#include "src/__support/macros/config.h"
-#include "src/__support/macros/optimization.h"
+#include "src/__support/math/acoshf16.h"
namespace LIBC_NAMESPACE_DECL {
-static constexpr size_t N_EXCEPTS = 2;
-static constexpr fputil::ExceptValues<float16, N_EXCEPTS> ACOSHF16_EXCEPTS{{
- // (input, RZ output, RU offset, RD offset, RN offset)
- // x = 0x1.6dcp+1, acoshf16(x) = 0x1.b6p+0 (RZ)
- {0x41B7, 0x3ED8, 1, 0, 0},
- // x = 0x1.39p+0, acoshf16(x) = 0x1.4f8p-1 (RZ)
- {0x3CE4, 0x393E, 1, 0, 1},
-}};
-
-LLVM_LIBC_FUNCTION(float16, acoshf16, (float16 x)) {
- using namespace acoshf_internal;
- using FPBits = fputil::FPBits<float16>;
- FPBits xbits(x);
- uint16_t x_u = xbits.uintval();
-
- // Check for NaN input first.
- if (LIBC_UNLIKELY(xbits.is_inf_or_nan())) {
- if (xbits.is_signaling_nan()) {
- fputil::raise_except_if_required(FE_INVALID);
- return FPBits::quiet_nan().get_val();
- }
- if (xbits.is_neg()) {
- fputil::set_errno_if_required(EDOM);
- fputil::raise_except_if_required(FE_INVALID);
- return FPBits::quiet_nan().get_val();
- }
- return x;
- }
-
- // Domain error for inputs less than 1.0.
- if (LIBC_UNLIKELY(x <= 1.0f)) {
- if (x == 1.0f)
- return FPBits::zero().get_val();
- fputil::set_errno_if_required(EDOM);
- fputil::raise_except_if_required(FE_INVALID);
- return FPBits::quiet_nan().get_val();
- }
-
- if (auto r = ACOSHF16_EXCEPTS.lookup(xbits.uintval());
- LIBC_UNLIKELY(r.has_value()))
- return r.value();
-
- float xf = x;
- // High-precision polynomial approximation for inputs close to 1.0
- // ([1, 1.25)).
- //
- // Brief derivation:
- // 1. Expand acosh(1 + delta) using Taylor series around delta=0:
- // acosh(1 + delta) ≈ sqrt(2 * delta) * [1 - delta/12 + 3*delta^2/160
- // - 5*delta^3/896 + 35*delta^4/18432 + ...]
- // 2. Truncate the series to fit accurately for delta in [0, 0.25].
- // 3. Polynomial coefficients (from sollya) used here are:
- // P(delta) ≈ 1 - 0x1.555556p-4 * delta + 0x1.333334p-6 * delta^2
- // - 0x1.6db6dcp-8 * delta^3 + 0x1.f1c71cp-10 * delta^4
- // 4. The Sollya commands used to generate these coefficients were:
- // > display = hexadecimal;
- // > round(1/12, SG, RN);
- // > round(3/160, SG, RN);
- // > round(5/896, SG, RN);
- // > round(35/18432, SG, RN);
- // With hexadecimal display mode enabled, the outputs were:
- // 0x1.555556p-4
- // 0x1.333334p-6
- // 0x1.6db6dcp-8
- // 0x1.f1c71cp-10
- // 5. The maximum absolute error, estimated using:
- // dirtyinfnorm(acosh(1 + x) - sqrt(2*x) * P(x), [0, 0.25])
- // is:
- // 0x1.d84281p-22
- if (LIBC_UNLIKELY(x_u < 0x3D00U)) {
- float delta = xf - 1.0f;
- float sqrt_2_delta = fputil::sqrt<float>(2.0 * delta);
- float pe = fputil::polyeval(delta, 0x1p+0f, -0x1.555556p-4f, 0x1.333334p-6f,
- -0x1.6db6dcp-8f, 0x1.f1c71cp-10f);
- float approx = sqrt_2_delta * pe;
- return fputil::cast<float16>(approx);
- }
-
- // acosh(x) = log(x + sqrt(x^2 - 1))
- float sqrt_term = fputil::sqrt<float>(fputil::multiply_add(xf, xf, -1.0f));
- float result = static_cast<float>(log_eval(xf + sqrt_term));
-
- return fputil::cast<float16>(result);
-}
+LLVM_LIBC_FUNCTION(float16, acoshf16, (float16 x)) { return math::acoshf16(x); }
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/shared/CMakeLists.txt b/libc/test/shared/CMakeLists.txt
index a402d6e39fa0b..89b607d7e5cc3 100644
--- a/libc/test/shared/CMakeLists.txt
+++ b/libc/test/shared/CMakeLists.txt
@@ -11,6 +11,7 @@ add_fp_unittest(
libc.src.__support.math.acosf
libc.src.__support.math.acosf16
libc.src.__support.math.acoshf
+ libc.src.__support.math.acoshf16
libc.src.__support.math.erff
libc.src.__support.math.exp
libc.src.__support.math.exp10
diff --git a/libc/test/shared/shared_math_test.cpp b/libc/test/shared/shared_math_test.cpp
index 25555b8caf534..8d3cebdf0745c 100644
--- a/libc/test/shared/shared_math_test.cpp
+++ b/libc/test/shared/shared_math_test.cpp
@@ -14,6 +14,8 @@
TEST(LlvmLibcSharedMathTest, AllFloat16) {
int exponent;
+ EXPECT_FP_EQ(0x0p+0f, LIBC_NAMESPACE::shared::acoshf16(1.0f));
+
EXPECT_FP_EQ(0x1p+0f16, LIBC_NAMESPACE::shared::exp10f16(0.0f16));
EXPECT_FP_EQ(0x1p+0f16, LIBC_NAMESPACE::shared::expf16(0.0f16));
diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
index 053d15869246b..88ccd05b54c1c 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -2141,6 +2141,22 @@ libc_support_library(
],
)
+libc_support_library(
+ name = "__support_math_acoshf16",
+ hdrs = ["src/__support/math/acoshf16.h"],
+ deps = [
+ ":__support_math_acoshf_utils",
+ ":__support_fputil_cast",
+ ":__support_fputil_except_value_utils",
+ ":__support_fputil_fenv_impl",
+ ":__support_fputil_fp_bits",
+ ":__support_fputil_multiply_add",
+ ":__support_fputil_polyeval",
+ ":__support_fputil_sqrt",
+ ":__support_macros_optimization",
+ ],
+)
+
libc_support_library(
name = "__support_math_asin_utils",
hdrs = ["src/__support/math/asin_utils.h"],
@@ -2682,6 +2698,14 @@ libc_math_function(
],
)
+libc_math_function(
+ name = "acoshf16",
+ additional_deps = [
+ ":__support_math_acoshf16",
+ ":errno",
+ ],
+)
+
libc_math_function(
name = "asinf",
additional_deps = [
|
lntue
approved these changes
Jul 21, 2025
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/153/builds/38854 Here is the relevant piece of the build log for the reference |
mahesh-attarde
pushed a commit
to mahesh-attarde/llvm-project
that referenced
this pull request
Jul 28, 2025
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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
Please merge #148418 first