[libc] [llvm] [libc][math] Refactor exp2f implementation to header-only in src/__support/math folder. (PR #161992)
Muhammad Bassiouni via llvm-commits
llvm-commits at lists.llvm.org
Mon Oct 6 10:40:43 PDT 2025
https://github.com/bassiounix updated https://github.com/llvm/llvm-project/pull/161992
>From a0d0c673da67b40d2ef8525aefcd4c49525c7b5a Mon Sep 17 00:00:00 2001
From: bassiounix <muhammad.m.bassiouni at gmail.com>
Date: Sun, 5 Oct 2025 06:09:45 +0300
Subject: [PATCH] [libc][math] Refactor exp2f implementation to header-only in
src/__support/math folder.
---
libc/shared/math.h | 1 +
libc/shared/math/exp2f.h | 23 ++++++++++++
libc/src/__support/math/CMakeLists.txt | 18 ++++++++++
.../exp2f_impl.h => __support/math/exp2f.h} | 22 ++++++------
libc/src/math/generic/CMakeLists.txt | 22 ++----------
libc/src/math/generic/exp2f.cpp | 4 +--
libc/src/math/generic/powf.cpp | 5 ++-
libc/test/shared/CMakeLists.txt | 1 +
libc/test/shared/shared_math_test.cpp | 1 +
.../llvm-project-overlay/libc/BUILD.bazel | 36 +++++++++----------
10 files changed, 80 insertions(+), 53 deletions(-)
create mode 100644 libc/shared/math/exp2f.h
rename libc/src/{math/generic/exp2f_impl.h => __support/math/exp2f.h} (94%)
diff --git a/libc/shared/math.h b/libc/shared/math.h
index 924d0cb4f3bfa..1262fa6f682d0 100644
--- a/libc/shared/math.h
+++ b/libc/shared/math.h
@@ -48,6 +48,7 @@
#include "math/exp10m1f.h"
#include "math/exp10m1f16.h"
#include "math/exp2.h"
+#include "math/exp2f.h"
#include "math/expf.h"
#include "math/expf16.h"
#include "math/frexpf.h"
diff --git a/libc/shared/math/exp2f.h b/libc/shared/math/exp2f.h
new file mode 100644
index 0000000000000..8c37cbb702e91
--- /dev/null
+++ b/libc/shared/math/exp2f.h
@@ -0,0 +1,23 @@
+//===-- Shared exp2f 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_EXP2F_H
+#define LLVM_LIBC_SHARED_MATH_EXP2F_H
+
+#include "shared/libc_common.h"
+#include "src/__support/math/exp2f.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::exp2f;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_MATH_EXP2F_H
diff --git a/libc/src/__support/math/CMakeLists.txt b/libc/src/__support/math/CMakeLists.txt
index 4130fdf02078b..203ebb4bf1760 100644
--- a/libc/src/__support/math/CMakeLists.txt
+++ b/libc/src/__support/math/CMakeLists.txt
@@ -735,6 +735,24 @@ add_header_library(
libc.src.errno.errno
)
+add_header_library(
+ exp2f
+ HDRS
+ exp2f.h
+ DEPENDS
+ .exp10f_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.FPUtil.nearest_integer
+ libc.src.__support.FPUtil.polyeval
+ libc.src.__support.FPUtil.rounding_mode
+ libc.src.__support.macros.optimization
+ libc.src.__support.common
+ libc.src.errno.errno
+)
+
add_header_library(
exp10
HDRS
diff --git a/libc/src/math/generic/exp2f_impl.h b/libc/src/__support/math/exp2f.h
similarity index 94%
rename from libc/src/math/generic/exp2f_impl.h
rename to libc/src/__support/math/exp2f.h
index b85bb1548019f..ef2aad051b8a9 100644
--- a/libc/src/math/generic/exp2f_impl.h
+++ b/libc/src/__support/math/exp2f.h
@@ -1,4 +1,4 @@
-//===-- Single-precision 2^x function -------------------------------------===//
+//===-- Implementation header for exp2f -------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
@@ -6,9 +6,10 @@
//
//===----------------------------------------------------------------------===//
-#ifndef LLVM_LIBC_SRC_MATH_GENERIC_EXP2F_IMPL_H
-#define LLVM_LIBC_SRC_MATH_GENERIC_EXP2F_IMPL_H
+#ifndef LLVM_LIBC_SRC___SUPPORT_MATH_EXP2F_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_EXP2F_H
+#include "exp10f_utils.h"
#include "src/__support/FPUtil/FEnvImpl.h"
#include "src/__support/FPUtil/FPBits.h"
#include "src/__support/FPUtil/PolyEval.h"
@@ -20,12 +21,12 @@
#include "src/__support/macros/config.h"
#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
#include "src/__support/macros/properties/cpu_features.h"
-#include "src/__support/math/exp10f_utils.h"
namespace LIBC_NAMESPACE_DECL {
-namespace generic {
-LIBC_INLINE float exp2f(float x) {
+namespace math {
+
+LIBC_INLINE static constexpr float exp2f(float x) {
using FPBits = typename fputil::FPBits<float>;
FPBits xbits(x);
@@ -120,8 +121,8 @@ LIBC_INLINE float exp2f(float x) {
// of 2^mid.
// kf = (hi + mid) * 2^5 = round(x * 2^5)
- float kf;
- int k;
+ float kf = 0;
+ int k = 0;
#ifdef LIBC_TARGET_CPU_HAS_NEAREST_INT
kf = fputil::nearest_integer(x * 32.0f);
k = static_cast<int>(kf);
@@ -161,7 +162,8 @@ LIBC_INLINE float exp2f(float x) {
return static_cast<float>(fputil::multiply_add(p, dx_sq * mh, c1 * mh));
}
-} // namespace generic
+} // namespace math
+
} // namespace LIBC_NAMESPACE_DECL
-#endif // LLVM_LIBC_SRC_MATH_GENERIC_EXP2F_IMPL_H
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_EXP2F_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 28ea475f09656..5738fe86f6c7b 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -1451,24 +1451,6 @@ add_entrypoint_object(
libc.src.__support.math.exp2
)
-add_header_library(
- exp2f_impl
- HDRS
- exp2f_impl.h
- DEPENDS
- 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.nearest_integer
- libc.src.__support.FPUtil.polyeval
- libc.src.__support.FPUtil.rounding_mode
- libc.src.__support.macros.optimization
- libc.src.__support.math.exp10f_utils
- libc.src.__support.common
- libc.src.errno.errno
-)
-
add_entrypoint_object(
exp2f
SRCS
@@ -1476,7 +1458,7 @@ add_entrypoint_object(
HDRS
../exp2f.h
DEPENDS
- .exp2f_impl
+ libc.src.__support.math.exp2f
)
add_entrypoint_object(
@@ -1659,8 +1641,8 @@ add_entrypoint_object(
HDRS
../powf.h
DEPENDS
- .exp2f_impl
libc.src.__support.math.exp10f
+ libc.src.__support.math.exp2f
libc.src.__support.CPP.bit
libc.src.__support.FPUtil.fenv_impl
libc.src.__support.FPUtil.fp_bits
diff --git a/libc/src/math/generic/exp2f.cpp b/libc/src/math/generic/exp2f.cpp
index 60d6510f23699..3117f73b59bcf 100644
--- a/libc/src/math/generic/exp2f.cpp
+++ b/libc/src/math/generic/exp2f.cpp
@@ -9,10 +9,10 @@
#include "src/math/exp2f.h"
#include "src/__support/common.h" // for LLVM_LIBC_FUNCTION
#include "src/__support/macros/config.h"
-#include "src/math/generic/exp2f_impl.h"
+#include "src/__support/math/exp2f.h"
namespace LIBC_NAMESPACE_DECL {
-LLVM_LIBC_FUNCTION(float, exp2f, (float x)) { return generic::exp2f(x); }
+LLVM_LIBC_FUNCTION(float, exp2f, (float x)) { return math::exp2f(x); }
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/math/generic/powf.cpp b/libc/src/math/generic/powf.cpp
index 12246e9878758..dd2b6aa788b9b 100644
--- a/libc/src/math/generic/powf.cpp
+++ b/libc/src/math/generic/powf.cpp
@@ -20,10 +20,9 @@
#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
#include "src/__support/math/common_constants.h" // Lookup tables EXP_M1 and EXP_M2.
#include "src/__support/math/exp10f.h" // Speedup for powf(10, y) = exp10f(y)
+#include "src/__support/math/exp2f.h" // Speedup for powf(2, y) = exp2f(y)
#include "src/__support/math/exp_constants.h"
-#include "exp2f_impl.h" // Speedup for powf(2, y) = exp2f(y)
-
namespace LIBC_NAMESPACE_DECL {
using fputil::DoubleDouble;
@@ -779,7 +778,7 @@ LLVM_LIBC_FUNCTION(float, powf, (float x, float y)) {
#ifndef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
case 0x4000'0000: // x = 2.0f
// pow(2, y) = exp2(y)
- return generic::exp2f(y);
+ return math::exp2f(y);
case 0x4120'0000: // x = 10.0f
// pow(10, y) = exp10(y)
return math::exp10f(y);
diff --git a/libc/test/shared/CMakeLists.txt b/libc/test/shared/CMakeLists.txt
index 040f6356b2577..dbc3889c76471 100644
--- a/libc/test/shared/CMakeLists.txt
+++ b/libc/test/shared/CMakeLists.txt
@@ -41,6 +41,7 @@ add_fp_unittest(
libc.src.__support.math.erff
libc.src.__support.math.exp
libc.src.__support.math.exp2
+ libc.src.__support.math.exp2f
libc.src.__support.math.exp10
libc.src.__support.math.exp10f
libc.src.__support.math.exp10f16
diff --git a/libc/test/shared/shared_math_test.cpp b/libc/test/shared/shared_math_test.cpp
index ef2e7b8d71456..d118d96da69dd 100644
--- a/libc/test/shared/shared_math_test.cpp
+++ b/libc/test/shared/shared_math_test.cpp
@@ -62,6 +62,7 @@ TEST(LlvmLibcSharedMathTest, AllFloat) {
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));
+ EXPECT_FP_EQ(0x1p+0f, LIBC_NAMESPACE::shared::exp2f(0.0f));
EXPECT_FP_EQ_ALL_ROUNDING(0.75f,
LIBC_NAMESPACE::shared::frexpf(24.0f, &exponent));
diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
index e91e7c8aa7c86..00db514beaf34 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -2167,22 +2167,6 @@ libc_support_library(
],
)
-libc_support_library(
- name = "exp2f_impl",
- hdrs = ["src/math/generic/exp2f_impl.h"],
- deps = [
- ":__support_fputil_except_value_utils",
- ":__support_fputil_fma",
- ":__support_fputil_multiply_add",
- ":__support_fputil_nearest_integer",
- ":__support_fputil_polyeval",
- ":__support_fputil_rounding_mode",
- ":__support_macros_optimization",
- ":__support_math_common_constants",
- ":__support_math_exp10f_utils",
- ],
-)
-
libc_support_library(
name = "__support_math_acos",
hdrs = ["src/__support/math/acos.h"],
@@ -2895,6 +2879,22 @@ libc_support_library(
],
)
+libc_support_library(
+ name = "__support_math_exp2f",
+ hdrs = ["src/__support/math/exp2f.h"],
+ deps = [
+ ":__support_fputil_except_value_utils",
+ ":__support_fputil_fma",
+ ":__support_fputil_multiply_add",
+ ":__support_fputil_nearest_integer",
+ ":__support_fputil_polyeval",
+ ":__support_fputil_rounding_mode",
+ ":__support_macros_optimization",
+ ":__support_math_common_constants",
+ ":__support_math_exp10f_utils",
+ ],
+)
+
libc_support_library(
name = "__support_math_exp10",
hdrs = ["src/__support/math/exp10.h"],
@@ -3676,7 +3676,7 @@ libc_math_function(
libc_math_function(
name = "exp2f",
additional_deps = [
- ":exp2f_impl",
+ ":__support_math_exp2f",
],
)
@@ -4511,7 +4511,7 @@ libc_math_function(
":__support_macros_optimization",
":__support_math_exp10f",
":__support_math_common_constants",
- ":exp2f_impl",
+ ":__support_math_exp2f",
],
)
More information about the llvm-commits
mailing list