[libc][math] Refactor cospif16 implementation to header-only in src/__support/math folder. #154222
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@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 Full diff: https://github.com/llvm/llvm-project/pull/154222.diff 9 Files Affected:
diff --git a/libc/shared/math.h b/libc/shared/math.h
index 6ab5df103bfb3..69d785b3e0291 100644
--- a/libc/shared/math.h
+++ b/libc/shared/math.h
@@ -38,6 +38,7 @@
#include "math/coshf.h"
#include "math/coshf16.h"
#include "math/cospif.h"
+#include "math/cospif16.h"
#include "math/erff.h"
#include "math/exp.h"
#include "math/exp10.h"
diff --git a/libc/shared/math/cospif16.h b/libc/shared/math/cospif16.h
new file mode 100644
index 0000000000000..bbb1f32e4ec1a
--- /dev/null
+++ b/libc/shared/math/cospif16.h
@@ -0,0 +1,28 @@
+//===-- Shared cospif16 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_COSPIF16_H
+#define LLVM_LIBC_SHARED_MATH_COSPIF16_H
+
+#include "shared/libc_common.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT16
+
+#include "src/__support/math/cospif.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::cospif16;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT16
+
+#endif // LLVM_LIBC_SHARED_MATH_COSPIF_H
diff --git a/libc/src/__support/math/CMakeLists.txt b/libc/src/__support/math/CMakeLists.txt
index 8ce6cef732d76..39dc0e57f4472 100644
--- a/libc/src/__support/math/CMakeLists.txt
+++ b/libc/src/__support/math/CMakeLists.txt
@@ -444,6 +444,19 @@ add_header_library(
libc.src.__support.macros.optimization
)
+add_header_library(
+ cospif16
+ HDRS
+ cospif16.h
+ DEPENDS
+ .sincosf16_utils
+ libc.src.__support.FPUtil.cast
+ libc.src.__support.FPUtil.fenv_impl
+ libc.src.__support.FPUtil.fp_bits
+ libc.src.__support.FPUtil.multiply_add
+ libc.src.__support.macros.optimization
+)
+
add_header_library(
erff
HDRS
diff --git a/libc/src/__support/math/cospif16.h b/libc/src/__support/math/cospif16.h
new file mode 100644
index 0000000000000..d07236cccac75
--- /dev/null
+++ b/libc/src/__support/math/cospif16.h
@@ -0,0 +1,99 @@
+//===-- Implementation header for cospif16 ----------------------*- 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_COSPIF16_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_COSPIF16_H
+
+#include "include/llvm-libc-macros/float16-macros.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT16
+
+#include "sincosf16_utils.h"
+#include "src/__support/FPUtil/FEnvImpl.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/FPUtil/cast.h"
+#include "src/__support/FPUtil/multiply_add.h"
+#include "src/__support/macros/optimization.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace math {
+
+LIBC_INLINE static constexpr float16 cospif16(float16 x) {
+
+ using namespace sincosf16_internal;
+ using FPBits = typename fputil::FPBits<float16>;
+ FPBits xbits(x);
+
+ uint16_t x_u = xbits.uintval();
+ uint16_t x_abs = x_u & 0x7fff;
+ float xf = x;
+
+ // 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 cosine of sum
+ // formula:
+ // cos(x * pi) = cos((k + y) * pi/32)
+ // = cos(k * pi/32) * cos(y * pi/32) +
+ // sin(y * pi/32) * sin(k * pi/32)
+
+ // For signed zeros
+ if (LIBC_UNLIKELY(x_abs == 0U))
+ return fputil::cast<float16>(1.0f);
+
+ // Numbers greater or equal to 2^10 are integers, or infinity, or NaN
+ if (LIBC_UNLIKELY(x_abs >= 0x6400)) {
+ if (LIBC_UNLIKELY(x_abs <= 0x67FF))
+ return fputil::cast<float16>((x_abs & 0x1) ? -1.0f : 1.0f);
+
+ // Check for NaN or infintiy values
+ if (LIBC_UNLIKELY(x_abs >= 0x7c00)) {
+ if (xbits.is_signaling_nan()) {
+ fputil::raise_except_if_required(FE_INVALID);
+ return FPBits::quiet_nan().get_val();
+ }
+ // If value is equal to infinity
+ if (x_abs == 0x7c00) {
+ fputil::set_errno_if_required(EDOM);
+ fputil::raise_except_if_required(FE_INVALID);
+ }
+
+ return x + FPBits::quiet_nan().get_val();
+ }
+
+ return fputil::cast<float16>(1.0f);
+ }
+
+ float sin_k = 0, cos_k = 0, sin_y = 0, cosm1_y = 0;
+ sincospif16_eval(xf, sin_k, cos_k, sin_y, cosm1_y);
+
+ if (LIBC_UNLIKELY(sin_y == 0 && cos_k == 0))
+ return fputil::cast<float16>(0.0f);
+
+ // Since, cosm1_y = cos_y - 1, therefore:
+ // cos(x * pi) = cos_k(cosm1_y) + cos_k - sin_k * sin_y
+ return fputil::cast<float16>(fputil::multiply_add(
+ cos_k, cosm1_y, fputil::multiply_add(-sin_k, sin_y, cos_k)));
+}
+
+} // namespace math
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT16
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_COSHF16_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 6c0dc1eeed692..5eba5e3616472 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -325,14 +325,7 @@ add_entrypoint_object(
HDRS
../cospif16.h
DEPENDS
- libc.hdr.errno_macros
- libc.hdr.fenv_macros
- libc.src.__support.FPUtil.cast
- 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.sincosf16_utils
+ libc.src.__support.math.cospif16
)
add_entrypoint_object(
diff --git a/libc/src/math/generic/cospif16.cpp b/libc/src/math/generic/cospif16.cpp
index c99285b25c106..a4bae8e13eac8 100644
--- a/libc/src/math/generic/cospif16.cpp
+++ b/libc/src/math/generic/cospif16.cpp
@@ -7,80 +7,10 @@
//===----------------------------------------------------------------------===//
#include "src/math/cospif16.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/cast.h"
-#include "src/__support/FPUtil/multiply_add.h"
-#include "src/__support/macros/optimization.h"
-#include "src/__support/math/sincosf16_utils.h"
+#include "src/__support/math/cospif16.h"
namespace LIBC_NAMESPACE_DECL {
-LLVM_LIBC_FUNCTION(float16, cospif16, (float16 x)) {
- using namespace sincosf16_internal;
- using FPBits = typename fputil::FPBits<float16>;
- FPBits xbits(x);
-
- uint16_t x_u = xbits.uintval();
- uint16_t x_abs = x_u & 0x7fff;
- float xf = x;
-
- // 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 cosine of sum
- // formula:
- // cos(x * pi) = cos((k + y) * pi/32)
- // = cos(k * pi/32) * cos(y * pi/32) +
- // sin(y * pi/32) * sin(k * pi/32)
-
- // For signed zeros
- if (LIBC_UNLIKELY(x_abs == 0U))
- return fputil::cast<float16>(1.0f);
-
- // Numbers greater or equal to 2^10 are integers, or infinity, or NaN
- if (LIBC_UNLIKELY(x_abs >= 0x6400)) {
- if (LIBC_UNLIKELY(x_abs <= 0x67FF))
- return fputil::cast<float16>((x_abs & 0x1) ? -1.0f : 1.0f);
-
- // Check for NaN or infintiy values
- if (LIBC_UNLIKELY(x_abs >= 0x7c00)) {
- if (xbits.is_signaling_nan()) {
- fputil::raise_except_if_required(FE_INVALID);
- return FPBits::quiet_nan().get_val();
- }
- // If value is equal to infinity
- if (x_abs == 0x7c00) {
- fputil::set_errno_if_required(EDOM);
- fputil::raise_except_if_required(FE_INVALID);
- }
-
- return x + FPBits::quiet_nan().get_val();
- }
-
- return fputil::cast<float16>(1.0f);
- }
-
- float sin_k, cos_k, sin_y, cosm1_y;
- sincospif16_eval(xf, sin_k, cos_k, sin_y, cosm1_y);
-
- if (LIBC_UNLIKELY(sin_y == 0 && cos_k == 0))
- return fputil::cast<float16>(0.0f);
-
- // Since, cosm1_y = cos_y - 1, therefore:
- // cos(x * pi) = cos_k(cosm1_y) + cos_k - sin_k * sin_y
- return fputil::cast<float16>(fputil::multiply_add(
- cos_k, cosm1_y, fputil::multiply_add(-sin_k, sin_y, cos_k)));
-}
+LLVM_LIBC_FUNCTION(float16, cospif16, (float16 x)) { return math::cospif16(x); }
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/shared/CMakeLists.txt b/libc/test/shared/CMakeLists.txt
index 89d5b243b20a3..48241d3f55287 100644
--- a/libc/test/shared/CMakeLists.txt
+++ b/libc/test/shared/CMakeLists.txt
@@ -34,6 +34,7 @@ add_fp_unittest(
libc.src.__support.math.coshf
libc.src.__support.math.coshf16
libc.src.__support.math.cospif
+ libc.src.__support.math.cospif16
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 c22543d3337ab..2e5a2d51146d4 100644
--- a/libc/test/shared/shared_math_test.cpp
+++ b/libc/test/shared/shared_math_test.cpp
@@ -23,6 +23,7 @@ TEST(LlvmLibcSharedMathTest, AllFloat16) {
EXPECT_FP_EQ(0x0p+0f16, LIBC_NAMESPACE::shared::atanhf16(0.0f16));
EXPECT_FP_EQ(0x1p+0f16, LIBC_NAMESPACE::shared::cosf16(0.0f16));
EXPECT_FP_EQ(0x1p+0f16, LIBC_NAMESPACE::shared::coshf16(0.0f16));
+ EXPECT_FP_EQ(0x1p+0f16, LIBC_NAMESPACE::shared::cospif16(0.0f16));
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 c4f347788fbc6..f8f7713655adb 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -2407,6 +2407,18 @@ libc_support_library(
],
)
+libc_support_library(
+ name = "__support_math_cospif16",
+ hdrs = ["src/__support/math/cospif16.h"],
+ deps = [
+ ":__support_fputil_cast",
+ ":__support_fputil_fenv_impl",
+ ":__support_fputil_multiply_add",
+ ":__support_macros_optimization",
+ ":__support_math_sincosf16_utils",
+ ],
+)
+
libc_support_library(
name = "__support_math_erff",
hdrs = ["src/__support/math/erff.h"],
@@ -3242,9 +3254,7 @@ libc_math_function(
libc_math_function(
name = "cospif16",
additional_deps = [
- ":__support_fputil_multiply_add",
- ":__support_macros_optimization",
- ":__support_math_sincosf16_utils",
+ ":__support_math_cospif16",
],
)
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This was referenced Sep 29, 2025
[libc][math] Refactor exp10m1f16 implementation to header-only in src/__support/math folder.
#161119
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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