[libc][math] Refactor atanhf implementation to header-only in src/__support/math folder. #151399

bassiounix · 2025-07-30T21:41:33Z

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

bassiounix · 2025-07-30T21:42:04Z

[libc][math] Refactor coshf implementation to header-only in src/__support/math folder. #153427
[libc][math] Refactor cosf16 implementation to header-only in src/__support/math folder. #152871
[libc][math] Refactor cosf implementation to header-only in src/__support/math folder. #152069
[libc][math] Refactor cos implementation to header-only in src/__support/math folder. #151883
[libc][math] Refactor cbrtf implementation to header-only in src/__support/math folder. #151846
[libc][math] Refactor cbrt implementation to header-only in src/__support/math folder. #151837
[libc][math] Refactor atanhf16 implementation to header-only in src/__support/math folder. #151779
[libc][math] Refactor atanhf implementation to header-only in src/__support/math folder. #151399 👈 (View in Graphite)
[libc][math] Refactor atan2f128 implementation to header-only in src/__support/math folder. #151012
[libc][math] Refactor atan2f implementation to header-only in src/__support/math folder. #150993
[libc][math] Refactor atan2 implementation to header-only in src/__support/math folder. #150968
[libc][math] Refactor atanf16 implementation to header-only in src/__support/math folder. #150868
[libc][math] Refactor atanf implementation to header-only in src/__support/math folder. #150854
[libc][math] Refactor atan implementation to header-only in src/__support/math folder. #150852
[libc][math] Refactor asinhf16 implementation to header-only in src/__support/math folder. #150849
[libc][math] Refactor asinhf implementation to header-only in src/__support/math folder. #150843
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llvmbot · 2025-07-30T21:42:27Z

@llvm/pr-subscribers-libc

Author: Muhammad Bassiouni (bassiounix)

Changes

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

Full diff: https://github.com/llvm/llvm-project/pull/151399.diff

9 Files Affected:

(modified) libc/shared/math.h (+1)
(added) libc/shared/math/atanhf.h (+23)
(modified) libc/src/__support/math/CMakeLists.txt (+11)
(added) libc/src/__support/math/atanhf.h (+76)
(modified) libc/src/math/generic/CMakeLists.txt (+1-4)
(modified) libc/src/math/generic/atanhf.cpp (+2-54)
(modified) libc/test/shared/CMakeLists.txt (+1)
(modified) libc/test/shared/shared_math_test.cpp (+1)
(modified) utils/bazel/llvm-project-overlay/libc/BUILD.bazel (+13-7)

diff --git a/libc/shared/math.h b/libc/shared/math.h
index 6cb583c08dedd..ddf219ece8ff1 100644
--- a/libc/shared/math.h
+++ b/libc/shared/math.h
@@ -28,6 +28,7 @@
 #include "math/atan2f128.h"
 #include "math/atanf.h"
 #include "math/atanf16.h"
+#include "math/atanhf.h"
 #include "math/erff.h"
 #include "math/exp.h"
 #include "math/exp10.h"
diff --git a/libc/shared/math/atanhf.h b/libc/shared/math/atanhf.h
new file mode 100644
index 0000000000000..763fb3e00a659
--- /dev/null
+++ b/libc/shared/math/atanhf.h
@@ -0,0 +1,23 @@
+//===-- Shared atanhf 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_ATANHF_H
+#define LLVM_LIBC_SHARED_MATH_ATANHF_H
+
+#include "shared/libc_common.h"
+#include "src/__support/math/atanhf.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::atanhf;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_MATH_ATANHF_H
diff --git a/libc/src/__support/math/CMakeLists.txt b/libc/src/__support/math/CMakeLists.txt
index caafdc2cbf1d6..500dd9de2c555 100644
--- a/libc/src/__support/math/CMakeLists.txt
+++ b/libc/src/__support/math/CMakeLists.txt
@@ -275,6 +275,17 @@ add_header_library(
     libc.src.__support.macros.optimization
 )
 
+add_header_library(
+  atanhf
+  HDRS
+    atanhf.h
+  DEPENDS
+    .acoshf_utils
+    libc.src.__support.FPUtil.fp_bits
+    libc.src.__support.FPUtil.fenv_impl
+    libc.src.__support.macros.optimization
+)
+
 add_header_library(
   asinf
   HDRS
diff --git a/libc/src/__support/math/atanhf.h b/libc/src/__support/math/atanhf.h
new file mode 100644
index 0000000000000..b3ee5bbb4d408
--- /dev/null
+++ b/libc/src/__support/math/atanhf.h
@@ -0,0 +1,76 @@
+//===-- Implementation header for atanhf ------------------------*- 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_ATANHF_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_ATANHF_H
+
+#include "acoshf_utils.h"
+#include "src/__support/FPUtil/FEnvImpl.h"
+#include "src/__support/FPUtil/FPBits.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 atanhf(float x) {
+  using namespace acoshf_internal;
+  using FPBits = typename fputil::FPBits<float>;
+
+  FPBits xbits(x);
+  Sign sign = xbits.sign();
+  uint32_t x_abs = xbits.abs().uintval();
+
+  // |x| >= 1.0
+  if (LIBC_UNLIKELY(x_abs >= 0x3F80'0000U)) {
+    if (xbits.is_nan()) {
+      if (xbits.is_signaling_nan()) {
+        fputil::raise_except_if_required(FE_INVALID);
+        return FPBits::quiet_nan().get_val();
+      }
+      return x;
+    }
+    // |x| == 1.0
+    if (x_abs == 0x3F80'0000U) {
+      fputil::set_errno_if_required(ERANGE);
+      fputil::raise_except_if_required(FE_DIVBYZERO);
+      return FPBits::inf(sign).get_val();
+    } else {
+      fputil::set_errno_if_required(EDOM);
+      fputil::raise_except_if_required(FE_INVALID);
+      return FPBits::quiet_nan().get_val();
+    }
+  }
+
+  // |x| < ~0.10
+  if (LIBC_UNLIKELY(x_abs <= 0x3dcc'0000U)) {
+    // |x| <= 2^-26
+    if (LIBC_UNLIKELY(x_abs <= 0x3280'0000U)) {
+      return static_cast<float>(LIBC_UNLIKELY(x_abs == 0)
+                                    ? x
+                                    : (x + 0x1.5555555555555p-2 * x * x * x));
+    }
+
+    double xdbl = x;
+    double x2 = xdbl * xdbl;
+    // Pure Taylor series.
+    double pe = fputil::polyeval(x2, 0.0, 0x1.5555555555555p-2,
+                                 0x1.999999999999ap-3, 0x1.2492492492492p-3,
+                                 0x1.c71c71c71c71cp-4, 0x1.745d1745d1746p-4);
+    return static_cast<float>(fputil::multiply_add(xdbl, pe, xdbl));
+  }
+  double xdbl = x;
+  return static_cast<float>(0.5 * log_eval((xdbl + 1.0) / (xdbl - 1.0)));
+}
+
+} // namespace math
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_ATANHF_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index dbab34bd9d5ed..bac043f1d7d00 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -3922,10 +3922,7 @@ add_entrypoint_object(
   HDRS
     ../atanhf.h
   DEPENDS
-    .explogxf
-    libc.src.__support.FPUtil.fp_bits
-    libc.src.__support.FPUtil.fenv_impl
-    libc.src.__support.macros.optimization
+    libc.src.__support.math.atanhf
 )
 
 add_entrypoint_object(
diff --git a/libc/src/math/generic/atanhf.cpp b/libc/src/math/generic/atanhf.cpp
index 602a8f042f783..81706190383ed 100644
--- a/libc/src/math/generic/atanhf.cpp
+++ b/libc/src/math/generic/atanhf.cpp
@@ -7,62 +7,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/math/atanhf.h"
-#include "src/__support/FPUtil/FEnvImpl.h"
-#include "src/__support/FPUtil/FPBits.h"
-#include "src/__support/macros/config.h"
-#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
-#include "src/math/generic/explogxf.h"
+#include "src/__support/math/atanhf.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
-LLVM_LIBC_FUNCTION(float, atanhf, (float x)) {
-  using namespace acoshf_internal;
-  using FPBits = typename fputil::FPBits<float>;
-
-  FPBits xbits(x);
-  Sign sign = xbits.sign();
-  uint32_t x_abs = xbits.abs().uintval();
-
-  // |x| >= 1.0
-  if (LIBC_UNLIKELY(x_abs >= 0x3F80'0000U)) {
-    if (xbits.is_nan()) {
-      if (xbits.is_signaling_nan()) {
-        fputil::raise_except_if_required(FE_INVALID);
-        return FPBits::quiet_nan().get_val();
-      }
-      return x;
-    }
-    // |x| == 1.0
-    if (x_abs == 0x3F80'0000U) {
-      fputil::set_errno_if_required(ERANGE);
-      fputil::raise_except_if_required(FE_DIVBYZERO);
-      return FPBits::inf(sign).get_val();
-    } else {
-      fputil::set_errno_if_required(EDOM);
-      fputil::raise_except_if_required(FE_INVALID);
-      return FPBits::quiet_nan().get_val();
-    }
-  }
-
-  // |x| < ~0.10
-  if (LIBC_UNLIKELY(x_abs <= 0x3dcc'0000U)) {
-    // |x| <= 2^-26
-    if (LIBC_UNLIKELY(x_abs <= 0x3280'0000U)) {
-      return static_cast<float>(LIBC_UNLIKELY(x_abs == 0)
-                                    ? x
-                                    : (x + 0x1.5555555555555p-2 * x * x * x));
-    }
-
-    double xdbl = x;
-    double x2 = xdbl * xdbl;
-    // Pure Taylor series.
-    double pe = fputil::polyeval(x2, 0.0, 0x1.5555555555555p-2,
-                                 0x1.999999999999ap-3, 0x1.2492492492492p-3,
-                                 0x1.c71c71c71c71cp-4, 0x1.745d1745d1746p-4);
-    return static_cast<float>(fputil::multiply_add(xdbl, pe, xdbl));
-  }
-  double xdbl = x;
-  return static_cast<float>(0.5 * log_eval((xdbl + 1.0) / (xdbl - 1.0)));
-}
+LLVM_LIBC_FUNCTION(float, atanhf, (float x)) { return math::atanhf(x); }
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/shared/CMakeLists.txt b/libc/test/shared/CMakeLists.txt
index a2c9c824a443f..34236ad69473c 100644
--- a/libc/test/shared/CMakeLists.txt
+++ b/libc/test/shared/CMakeLists.txt
@@ -24,6 +24,7 @@ add_fp_unittest(
     libc.src.__support.math.atan2f128
     libc.src.__support.math.atanf
     libc.src.__support.math.atanf16
+    libc.src.__support.math.atanhf
     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 8626c723b372a..ffe1a2495604e 100644
--- a/libc/test/shared/shared_math_test.cpp
+++ b/libc/test/shared/shared_math_test.cpp
@@ -47,6 +47,7 @@ TEST(LlvmLibcSharedMathTest, AllFloat) {
   EXPECT_FP_EQ(0x0p+0f, LIBC_NAMESPACE::shared::asinhf(0.0f));
   EXPECT_FP_EQ(0x0p+0f, LIBC_NAMESPACE::shared::atan2f(0.0f, 0.0f));
   EXPECT_FP_EQ(0x0p+0f, LIBC_NAMESPACE::shared::atanf(0.0f));
+  EXPECT_FP_EQ(0x0p+0f, LIBC_NAMESPACE::shared::atanhf(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));
diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
index 346a17b4954f8..a3419f17463b6 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -2373,6 +2373,18 @@ libc_support_library(
     ],
 )
 
+libc_support_library(
+    name = "__support_math_atanhf",
+    hdrs = ["src/__support/math/atanhf.h"],
+    deps = [
+        ":__support_math_acoshf_utils",
+        ":__support_fputil_fenv_impl",
+        ":__support_fputil_fp_bits",
+        ":__support_macros_config",
+        ":__support_macros_optimization",
+    ],
+)
+
 libc_support_library(
     name = "__support_math_erff",
     hdrs = ["src/__support/math/erff.h"],
@@ -2998,13 +3010,7 @@ libc_math_function(
 libc_math_function(
     name = "atanhf",
     additional_deps = [
-        ":__support_fputil_fma",
-        ":__support_fputil_multiply_add",
-        ":__support_fputil_nearest_integer",
-        ":__support_fputil_polyeval",
-        ":__support_macros_optimization",
-        ":common_constants",
-        ":explogxf",
+        ":__support_math_atanhf",
     ],
 )

bassiounix · 2025-08-01T23:45:40Z

Merge activity

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Aug 1, 11:47 PM UTC: Graphite rebased this pull request as part of a merge.
Aug 1, 11:54 PM UTC: @bassiounix merged this pull request with Graphite.

…upport/math folder.

…upport/math folder. (llvm#151399) Part of llvm#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

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[libc][math] Refactor atan2 implementation to header-only in src/__support/math folder. #150968

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[libc][math] Refactor atan2f implementation to header-only in src/__support/math folder. #150993

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[libc][math] Refactor atan2f128 implementation to header-only in src/__support/math folder. #151012

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[libc][math] Tracking Issue - Refactor Higher Math Functions to Header Only #147386

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[libc][math] Refactor atanhf16 implementation to header-only in src/__support/math folder. #151779

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[libc][math] Refactor coshf implementation to header-only in src/__support/math folder. #153427

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