[libc][math] Refactor atanf16 implementation to header-only in src/__support/math folder.

libc/shared/math.h

@@ -24,6 +24,7 @@
 #include "math/asinhf16.h"
 #include "math/atan.h"
 #include "math/atanf.h"
+#include "math/atanf16.h"
 #include "math/erff.h"
 #include "math/exp.h"
 #include "math/exp10.h"

libc/shared/math/atanf16.h

@@ -0,0 +1,28 @@
+//===-- Shared atanf16 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_ATANF16_H
+#define LLVM_LIBC_SHARED_MATH_ATANF16_H
+
+#include "shared/libc_common.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT16
+
+#include "src/__support/math/atanf16.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::atanf16;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT16
+
+#endif // LLVM_LIBC_SHARED_MATH_ATANF16_H

libc/src/__support/math/CMakeLists.txt

@@ -214,6 +214,21 @@ add_header_library(
     libc.src.__support.macros.optimization
 )
 
+add_header_library(
+  atanf16
+  HDRS
+    atanf16.h
+  DEPENDS
+    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(
   asinf
   HDRS

libc/src/__support/math/atanf16.h

@@ -0,0 +1,119 @@
+//===-- Implementation header for atanf16 -----------------------*- 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_ATANF16_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_ATANF16_H
+
+#include "include/llvm-libc-macros/float16-macros.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT16
+
+#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/optimization.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace math {
+
+LIBC_INLINE static constexpr float16 atanf16(float16 x) {
+  // Generated by Solly using the following command:
+  // > round(pi/2, SG, RN);
+  constexpr float PI_2 = 0x1.921fb6p0;
+
+#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
+  constexpr size_t N_EXCEPTS = 6;
+
+  constexpr fputil::ExceptValues<float16, N_EXCEPTS> ATANF16_EXCEPTS{{
+      // (input, RZ output, RU offset, RD offset, RN offset)
+      {0x2745, 0x2744, 1, 0, 1},
+      {0x3099, 0x3090, 1, 0, 1},
+      {0x3c6c, 0x3aae, 1, 0, 1},
+      {0x466e, 0x3daa, 1, 0, 1},
+      {0x48ae, 0x3ddb, 1, 0, 0},
+      {0x5619, 0x3e3d, 1, 0, 1},
+  }};
+#endif // !LIBC_MATH_HAS_SKIP_ACCURATE_PASS
+
+  using FPBits = fputil::FPBits<float16>;
+  FPBits xbits(x);
+
+  uint16_t x_u = xbits.uintval();
+  uint16_t x_abs = x_u & 0x7fff;
+  bool x_sign = x_u >> 15;
+  float sign = (x_sign ? -1.0 : 1.0);
+
+  // |x| >= +/-inf
+  if (LIBC_UNLIKELY(x_abs >= 0x7c00)) {
+    if (xbits.is_nan()) {
+      if (xbits.is_signaling_nan()) {
+        fputil::raise_except_if_required(FE_INVALID);
+        return FPBits::quiet_nan().get_val();
+      }
+      return x;
+    }
+
+    // atanf16(+/-inf) = +/-pi/2
+    return fputil::cast<float16>(sign * PI_2);
+  }
+
+  float xf = x;
+  float xsq = xf * xf;
+#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
+  // Handle exceptional values
+  if (auto r = ATANF16_EXCEPTS.lookup_odd(x_abs, x_sign);
+      LIBC_UNLIKELY(r.has_value()))
+    return r.value();
+#endif
+
+  // |x| <= 0x1p0, |x| <= 1
+  if (x_abs <= 0x3c00) {
+    // atanf16(+/-0) = +/-0
+    if (LIBC_UNLIKELY(x_abs == 0))
+      return x;
+
+    // Degree-14 minimax odd polynomial of atan(x) generated by Sollya with:
+    // > P = fpminimax(atan(x)/x, [|0, 2, 4, 6, 8, 10, 12, 14|], [|SG...|],
+    // [0, 1]);
+    float result = fputil::polyeval(
+        xsq, 0x1.fffffcp-1f, -0x1.55519ep-2f, 0x1.98f6a8p-3f, -0x1.1f0a92p-3f,
+        0x1.95b654p-4f, -0x1.e65492p-5f, 0x1.8c0c36p-6f, -0x1.32316ep-8f);
+    return fputil::cast<float16>(xf * result);
+  }
+
+  // If |x| > 1
+  // y = atan(x) = sign(x) * atan(|x|)
+  // atan(|x|) = pi/2 - atan(1/|x|)
+  // Recall, 1/|x| < 1
+  float x_inv_sq = 1.0f / xsq;
+  float x_inv = fputil::sqrt<float>(x_inv_sq);
+
+  // Degree-14 minimax odd polynomial of atan(x) generated by Sollya with:
+  // > P = fpminimax(atan(x)/x, [|0, 2, 4, 6, 8, 10, 12, 14|], [|SG...|],
+  // [0, 1]);
+  float interm =
+      fputil::polyeval(x_inv_sq, 0x1.fffffcp-1f, -0x1.55519ep-2f,
+                       0x1.98f6a8p-3f, -0x1.1f0a92p-3f, 0x1.95b654p-4f,
+                       -0x1.e65492p-5f, 0x1.8c0c36p-6f, -0x1.32316ep-8f);
+
+  return fputil::cast<float16>(sign *
+                               fputil::multiply_add(x_inv, -interm, PI_2));
+}
+
+} // namespace math
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT16
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_ATANF16_H

libc/src/math/generic/CMakeLists.txt

@@ -4037,17 +4037,7 @@ add_entrypoint_object(
   HDRS
     ../atanf16.h
   DEPENDS
-    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.atanf16
 )
 
 add_entrypoint_object(

libc/src/math/generic/atanf16.cpp

@@ -7,101 +7,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/math/atanf16.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/macros/optimization.h"
+#include "src/__support/math/atanf16.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
-// Generated by Solly using the following command:
-// > round(pi/2, SG, RN);
-static constexpr float PI_2 = 0x1.921fb6p0;
-
-#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
-static constexpr size_t N_EXCEPTS = 6;
-
-static constexpr fputil::ExceptValues<float16, N_EXCEPTS> ATANF16_EXCEPTS{{
-    // (input, RZ output, RU offset, RD offset, RN offset)
-    {0x2745, 0x2744, 1, 0, 1},
-    {0x3099, 0x3090, 1, 0, 1},
-    {0x3c6c, 0x3aae, 1, 0, 1},
-    {0x466e, 0x3daa, 1, 0, 1},
-    {0x48ae, 0x3ddb, 1, 0, 0},
-    {0x5619, 0x3e3d, 1, 0, 1},
-}};
-#endif // !LIBC_MATH_HAS_SKIP_ACCURATE_PASS
-
-LLVM_LIBC_FUNCTION(float16, atanf16, (float16 x)) {
-  using FPBits = fputil::FPBits<float16>;
-  FPBits xbits(x);
-
-  uint16_t x_u = xbits.uintval();
-  uint16_t x_abs = x_u & 0x7fff;
-  bool x_sign = x_u >> 15;
-  float sign = (x_sign ? -1.0 : 1.0);
-
-  // |x| >= +/-inf
-  if (LIBC_UNLIKELY(x_abs >= 0x7c00)) {
-    if (xbits.is_nan()) {
-      if (xbits.is_signaling_nan()) {
-        fputil::raise_except_if_required(FE_INVALID);
-        return FPBits::quiet_nan().get_val();
-      }
-      return x;
-    }
-
-    // atanf16(+/-inf) = +/-pi/2
-    return fputil::cast<float16>(sign * PI_2);
-  }
-
-  float xf = x;
-  float xsq = xf * xf;
-#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
-  // Handle exceptional values
-  if (auto r = ATANF16_EXCEPTS.lookup_odd(x_abs, x_sign);
-      LIBC_UNLIKELY(r.has_value()))
-    return r.value();
-#endif
-
-  // |x| <= 0x1p0, |x| <= 1
-  if (x_abs <= 0x3c00) {
-    // atanf16(+/-0) = +/-0
-    if (LIBC_UNLIKELY(x_abs == 0))
-      return x;
-
-    // Degree-14 minimax odd polynomial of atan(x) generated by Sollya with:
-    // > P = fpminimax(atan(x)/x, [|0, 2, 4, 6, 8, 10, 12, 14|], [|SG...|],
-    // [0, 1]);
-    float result = fputil::polyeval(
-        xsq, 0x1.fffffcp-1f, -0x1.55519ep-2f, 0x1.98f6a8p-3f, -0x1.1f0a92p-3f,
-        0x1.95b654p-4f, -0x1.e65492p-5f, 0x1.8c0c36p-6f, -0x1.32316ep-8f);
-    return fputil::cast<float16>(xf * result);
-  }
-
-  // If |x| > 1
-  // y = atan(x) = sign(x) * atan(|x|)
-  // atan(|x|) = pi/2 - atan(1/|x|)
-  // Recall, 1/|x| < 1
-  float x_inv_sq = 1.0f / xsq;
-  float x_inv = fputil::sqrt<float>(x_inv_sq);
-
-  // Degree-14 minimax odd polynomial of atan(x) generated by Sollya with:
-  // > P = fpminimax(atan(x)/x, [|0, 2, 4, 6, 8, 10, 12, 14|], [|SG...|],
-  // [0, 1]);
-  float interm =
-      fputil::polyeval(x_inv_sq, 0x1.fffffcp-1f, -0x1.55519ep-2f,
-                       0x1.98f6a8p-3f, -0x1.1f0a92p-3f, 0x1.95b654p-4f,
-                       -0x1.e65492p-5f, 0x1.8c0c36p-6f, -0x1.32316ep-8f);
-
-  return fputil::cast<float16>(sign *
-                               fputil::multiply_add(x_inv, -interm, PI_2));
-}
+LLVM_LIBC_FUNCTION(float16, atanf16, (float16 x)) { return math::atanf16(x); }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/test/shared/CMakeLists.txt

@@ -20,6 +20,7 @@ add_fp_unittest(
     libc.src.__support.math.asinhf16
     libc.src.__support.math.atan
     libc.src.__support.math.atanf
+    libc.src.__support.math.atanf16
     libc.src.__support.math.erff
     libc.src.__support.math.exp
     libc.src.__support.math.exp10

libc/test/shared/shared_math_test.cpp

@@ -19,6 +19,7 @@ TEST(LlvmLibcSharedMathTest, AllFloat16) {
   EXPECT_FP_EQ(0x0p+0f16, LIBC_NAMESPACE::shared::acospif16(1.0f16));
   EXPECT_FP_EQ(0x0p+0f16, LIBC_NAMESPACE::shared::asinf16(0.0f16));
   EXPECT_FP_EQ(0x0p+0f16, LIBC_NAMESPACE::shared::asinhf16(0.0f16));
+  EXPECT_FP_EQ(0x0p+0f16, LIBC_NAMESPACE::shared::atanf16(0.0f16));
 
   EXPECT_FP_EQ(0x1p+0f16, LIBC_NAMESPACE::shared::exp10f16(0.0f16));
 

utils/bazel/llvm-project-overlay/libc/BUILD.bazel

@@ -2288,6 +2288,21 @@ libc_support_library(
     ],
 )
 
+libc_support_library(
+    name = "__support_math_atanf16",
+    hdrs = ["src/__support/math/atanf16.h"],
+    deps = [
+        ":__support_fputil_cast",
+        ":__support_fputil_except_value_utils",
+        ":__support_fputil_fenv_impl",
+        ":__support_fputil_fp_bits",
+        ":__support_fputil_polyeval",
+        ":__support_fputil_multiply_add",
+        ":__support_fputil_sqrt",
+        ":__support_macros_optimization",
+    ],
+)
+
 libc_support_library(
     name = "__support_math_asinf",
     hdrs = ["src/__support/math/asinf.h"],
@@ -2904,6 +2919,13 @@ libc_math_function(
     ],
 )
 
+libc_math_function(
+    name = "atanf16",
+    additional_deps = [
+        ":__support_math_atanf16"
+    ],
+)
+
 libc_math_function(
     name = "atan",
     additional_deps = [