[libc-commits] [libc] [llvm] [libc][math] Refactor tanpif to header only (PR #181525)
Xinlong Chen via libc-commits
libc-commits at lists.llvm.org
Sat Feb 14 21:21:30 PST 2026
https://github.com/Xinlong-Chen created https://github.com/llvm/llvm-project/pull/181525
Part of https://github.com/llvm/llvm-project/issues/147386
>From b586437cd5821ae2387403ec46fc3a247cdd821d Mon Sep 17 00:00:00 2001
From: xinlongchen <xinlongchen at tencent.com>
Date: Sun, 15 Feb 2026 12:49:48 +0800
Subject: [PATCH] [libc][math] Refactor tanpif implementation to header-only in
src/__support/math folder.
---
libc/shared/math.h | 1 +
libc/shared/math/tanpif.h | 23 ++++
libc/src/__support/math/CMakeLists.txt | 16 +++
libc/src/__support/math/tanpif.h | 120 ++++++++++++++++++
libc/src/math/generic/CMakeLists.txt | 7 +-
libc/src/math/generic/tanpif.cpp | 95 +-------------
libc/test/shared/CMakeLists.txt | 1 +
libc/test/shared/shared_math_test.cpp | 1 +
.../llvm-project-overlay/libc/BUILD.bazel | 22 +++-
9 files changed, 182 insertions(+), 104 deletions(-)
create mode 100644 libc/shared/math/tanpif.h
create mode 100644 libc/src/__support/math/tanpif.h
diff --git a/libc/shared/math.h b/libc/shared/math.h
index e4487d7305e4b..c7128046b44ed 100644
--- a/libc/shared/math.h
+++ b/libc/shared/math.h
@@ -124,5 +124,6 @@
#include "math/tanf.h"
#include "math/tanhf.h"
#include "math/tanhf16.h"
+#include "math/tanpif.h"
#endif // LLVM_LIBC_SHARED_MATH_H
diff --git a/libc/shared/math/tanpif.h b/libc/shared/math/tanpif.h
new file mode 100644
index 0000000000000..4c1f691ddb1d2
--- /dev/null
+++ b/libc/shared/math/tanpif.h
@@ -0,0 +1,23 @@
+//===-- Shared tanpif 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_TANPIF_H
+#define LLVM_LIBC_SHARED_MATH_TANPIF_H
+
+#include "shared/libc_common.h"
+#include "src/__support/math/tanpif.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::tanpif;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_MATH_TANPIF_H
diff --git a/libc/src/__support/math/CMakeLists.txt b/libc/src/__support/math/CMakeLists.txt
index 8027180e2cf08..84d7719a8f3b7 100644
--- a/libc/src/__support/math/CMakeLists.txt
+++ b/libc/src/__support/math/CMakeLists.txt
@@ -1786,3 +1786,19 @@ add_header_library(
libc.src.__support.macros.optimization
libc.include.llvm-libc-macros.float16_macros
)
+
+add_header_library(
+ tanpif
+ HDRS
+ tanpif.h
+ DEPENDS
+ .sincosf16_utils
+ libc.src.__support.FPUtil.fenv_impl
+ libc.src.__support.FPUtil.fp_bits
+ libc.src.__support.FPUtil.cast
+ libc.src.__support.FPUtil.except_value_utils
+ libc.src.__support.FPUtil.multiply_add
+ libc.src.__support.common
+ libc.src.__support.macros.config
+ libc.src.__support.macros.optimization
+)
\ No newline at end of file
diff --git a/libc/src/__support/math/tanpif.h b/libc/src/__support/math/tanpif.h
new file mode 100644
index 0000000000000..36be1bfbec631
--- /dev/null
+++ b/libc/src/__support/math/tanpif.h
@@ -0,0 +1,120 @@
+//===-- Single-precision tanpi 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_MATH_TANPIF_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_TANPIF_H
+
+#include "sincosf_utils.h"
+#include "src/__support/FPUtil/FEnvImpl.h"
+#include "src/__support/FPUtil/FPBits.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/common.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace math {
+
+namespace tanpif_internal {
+#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
+LIBC_INLINE_VAR constexpr size_t N_EXCEPTS = 3;
+
+LIBC_INLINE_VAR constexpr fputil::ExceptValues<float, N_EXCEPTS> TANPIF_EXCEPTS{
+ {
+ // (input, RZ output, RU offset, RD offset, RN offset)
+ {0x38F26685, 0x39BE6182, 1, 0, 0},
+ {0x3E933802, 0x3FA267DD, 1, 0, 0},
+ {0x3F3663FF, 0xBFA267DD, 0, 1, 0},
+ }};
+#endif // !LIBC_MATH_HAS_SKIP_ACCURATE_PASS
+} // namespace tanpif_internal
+
+LIBC_INLINE float tanpif(float x) {
+ using namespace sincosf_utils_internal;
+ using namespace tanpif_internal;
+
+ using FPBits = typename fputil::FPBits<float>;
+ FPBits xbits(x);
+
+ uint32_t x_u = xbits.uintval();
+ uint32_t x_abs = x_u & 0x7fff'ffffU;
+ double xd = static_cast<double>(xbits.get_val());
+
+ // Handle exceptional values
+ if (LIBC_UNLIKELY(x_abs <= 0x3F3663FF)) {
+ if (LIBC_UNLIKELY(x_abs == 0U))
+ return x;
+
+#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
+ bool x_sign = x_u >> 31;
+
+ if (auto r = TANPIF_EXCEPTS.lookup_odd(x_abs, x_sign);
+ LIBC_UNLIKELY(r.has_value()))
+ return r.value();
+#endif // !LIBC_MATH_HAS_SKIP_ACCURATE_PASS
+ }
+
+ // Numbers greater or equal to 2^23 are always integers, or infinity, or NaN
+ if (LIBC_UNLIKELY(x_abs >= 0x4B00'0000)) {
+ // x is inf or NaN.
+ if (LIBC_UNLIKELY(x_abs >= 0x7f80'0000U)) {
+ if (xbits.is_signaling_nan()) {
+ fputil::raise_except_if_required(FE_INVALID);
+ return FPBits::quiet_nan().get_val();
+ }
+
+ if (x_abs == 0x7f80'0000U) {
+ fputil::set_errno_if_required(EDOM);
+ fputil::raise_except_if_required(FE_INVALID);
+ }
+
+ return x + FPBits::quiet_nan().get_val();
+ }
+
+ return FPBits::zero(xbits.sign()).get_val();
+ }
+
+ // Range reduction:
+ // For |x| > 1/32, we perform range reduction as follows:
+ // Find k and y such that:
+ // x = (k + y) * 1/32
+ // k is an integer
+ // |y| < 0.5
+ //
+ // This is done by performing:
+ // k = round(x * 32)
+ // y = x * 32 - k
+ //
+ // Once k and y are computed, we then deduce the answer by the formula:
+ // tan(x) = sin(x) / cos(x)
+ // = (sin_y * cos_k + cos_y * sin_k) / (cos_y * cos_k - sin_y * sin_k)
+ double sin_k, cos_k, sin_y, cosm1_y;
+ sincospif_eval(xd, sin_k, cos_k, sin_y, cosm1_y);
+
+ if (LIBC_UNLIKELY(sin_y == 0 && cos_k == 0)) {
+ fputil::set_errno_if_required(EDOM);
+ fputil::raise_except_if_required(FE_DIVBYZERO);
+
+ int32_t x_mp5_i = static_cast<int32_t>(xd - 0.5);
+ return FPBits::inf((x_mp5_i & 0x1) ? Sign::NEG : Sign::POS).get_val();
+ }
+
+ using fputil::multiply_add;
+ return fputil::cast<float>(
+ multiply_add(sin_y, cos_k, multiply_add(cosm1_y, sin_k, sin_k)) /
+ multiply_add(sin_y, -sin_k, multiply_add(cosm1_y, cos_k, cos_k)));
+}
+
+} // namespace math
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_TANPIF_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index b7c1f5a911831..39282a4db978e 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -494,12 +494,7 @@ add_entrypoint_object(
HDRS
../tanpif.h
DEPENDS
- libc.src.__support.math.sincosf_utils
- 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.macros.optimization
+ libc.src.__support.math.tanpif
)
add_entrypoint_object(
diff --git a/libc/src/math/generic/tanpif.cpp b/libc/src/math/generic/tanpif.cpp
index 44df22b517a46..e3568d6e9d35c 100644
--- a/libc/src/math/generic/tanpif.cpp
+++ b/libc/src/math/generic/tanpif.cpp
@@ -7,101 +7,10 @@
//===----------------------------------------------------------------------===//
#include "src/math/tanpif.h"
-#include "src/__support/FPUtil/FEnvImpl.h"
-#include "src/__support/FPUtil/FPBits.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/common.h"
-#include "src/__support/macros/config.h"
-#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
-#include "src/__support/math/sincosf_utils.h"
+#include "src/__support/math/tanpif.h"
namespace LIBC_NAMESPACE_DECL {
-#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
-constexpr size_t N_EXCEPTS = 3;
-
-constexpr fputil::ExceptValues<float, N_EXCEPTS> TANPIF_EXCEPTS{{
- // (input, RZ output, RU offset, RD offset, RN offset)
- {0x38F26685, 0x39BE6182, 1, 0, 0},
- {0x3E933802, 0x3FA267DD, 1, 0, 0},
- {0x3F3663FF, 0xBFA267DD, 0, 1, 0},
-}};
-#endif // !LIBC_MATH_HAS_SKIP_ACCURATE_PASS
-
-LLVM_LIBC_FUNCTION(float, tanpif, (float x)) {
- using namespace math::sincosf_utils_internal;
- using FPBits = typename fputil::FPBits<float>;
- FPBits xbits(x);
-
- uint32_t x_u = xbits.uintval();
- uint32_t x_abs = x_u & 0x7fff'ffffU;
- double xd = static_cast<double>(xbits.get_val());
-
- // Handle exceptional values
- if (LIBC_UNLIKELY(x_abs <= 0x3F3663FF)) {
- if (LIBC_UNLIKELY(x_abs == 0U))
- return x;
-
-#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
- bool x_sign = x_u >> 31;
-
- if (auto r = TANPIF_EXCEPTS.lookup_odd(x_abs, x_sign);
- LIBC_UNLIKELY(r.has_value()))
- return r.value();
-#endif // !LIBC_MATH_HAS_SKIP_ACCURATE_PASS
- }
-
- // Numbers greater or equal to 2^23 are always integers, or infinity, or NaN
- if (LIBC_UNLIKELY(x_abs >= 0x4B00'0000)) {
- // x is inf or NaN.
- if (LIBC_UNLIKELY(x_abs >= 0x7f80'0000U)) {
- if (xbits.is_signaling_nan()) {
- fputil::raise_except_if_required(FE_INVALID);
- return FPBits::quiet_nan().get_val();
- }
-
- if (x_abs == 0x7f80'0000U) {
- fputil::set_errno_if_required(EDOM);
- fputil::raise_except_if_required(FE_INVALID);
- }
-
- return x + FPBits::quiet_nan().get_val();
- }
-
- return FPBits::zero(xbits.sign()).get_val();
- }
-
- // Range reduction:
- // For |x| > 1/32, we perform range reduction as follows:
- // Find k and y such that:
- // x = (k + y) * 1/32
- // k is an integer
- // |y| < 0.5
- //
- // This is done by performing:
- // k = round(x * 32)
- // y = x * 32 - k
- //
- // Once k and y are computed, we then deduce the answer by the formula:
- // tan(x) = sin(x) / cos(x)
- // = (sin_y * cos_k + cos_y * sin_k) / (cos_y * cos_k - sin_y * sin_k)
- double sin_k, cos_k, sin_y, cosm1_y;
- sincospif_eval(xd, sin_k, cos_k, sin_y, cosm1_y);
-
- if (LIBC_UNLIKELY(sin_y == 0 && cos_k == 0)) {
- fputil::set_errno_if_required(EDOM);
- fputil::raise_except_if_required(FE_DIVBYZERO);
-
- int32_t x_mp5_i = static_cast<int32_t>(xd - 0.5);
- return FPBits::inf((x_mp5_i & 0x1) ? Sign::NEG : Sign::POS).get_val();
- }
-
- using fputil::multiply_add;
- return fputil::cast<float>(
- multiply_add(sin_y, cos_k, multiply_add(cosm1_y, sin_k, sin_k)) /
- multiply_add(sin_y, -sin_k, multiply_add(cosm1_y, cos_k, cos_k)));
-}
+LLVM_LIBC_FUNCTION(float, tanpif, (float x)) { return math::tanpif(x); }
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/shared/CMakeLists.txt b/libc/test/shared/CMakeLists.txt
index 1a0559af51acd..9fd3edfca1af9 100644
--- a/libc/test/shared/CMakeLists.txt
+++ b/libc/test/shared/CMakeLists.txt
@@ -121,4 +121,5 @@ add_fp_unittest(
libc.src.__support.math.tanf
libc.src.__support.math.tanhf
libc.src.__support.math.tanhf16
+ libc.src.__support.math.tanpif
)
diff --git a/libc/test/shared/shared_math_test.cpp b/libc/test/shared/shared_math_test.cpp
index fc6e6c74b3720..cb3893f81d9e0 100644
--- a/libc/test/shared/shared_math_test.cpp
+++ b/libc/test/shared/shared_math_test.cpp
@@ -129,6 +129,7 @@ TEST(LlvmLibcSharedMathTest, AllFloat) {
EXPECT_FP_EQ(0.0f, LIBC_NAMESPACE::shared::sqrtf(0.0f));
EXPECT_FP_EQ(0.0f, LIBC_NAMESPACE::shared::tanf(0.0f));
EXPECT_FP_EQ(0.0f, LIBC_NAMESPACE::shared::tanhf(0.0f));
+ EXPECT_FP_EQ(0.0f, LIBC_NAMESPACE::shared::tanpif(0.0f));
}
TEST(LlvmLibcSharedMathTest, AllDouble) {
diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
index 0eaff89f04215..5862864830c89 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -3982,6 +3982,22 @@ libc_support_library(
],
)
+libc_support_library(
+ name = "__support_math_tanpif",
+ hdrs = ["src/__support/math/tanpif.h"],
+ deps = [
+ ":__support_common",
+ ":__support_fputil_cast",
+ ":__support_fputil_except_value_utils",
+ ":__support_fputil_fenv_impl",
+ ":__support_fputil_fp_bits",
+ ":__support_fputil_multiply_add",
+ ":__support_macros_config",
+ ":__support_macros_optimization",
+ ":__support_sincosf_utils",
+ ],
+)
+
############################### complex targets ################################
libc_function(
@@ -5495,11 +5511,7 @@ libc_math_function(
libc_math_function(
name = "tanpif",
additional_deps = [
- ":__support_sincosf_utils",
- ":hdr_fenv_macros",
- ":__support_macros_config",
- ":__support_macros_optimization",
- ":__support_fputil_multiply_add",
+ ":__support_math_tanpif",
],
)
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