[libc-commits] [libc] [llvm] [libc][math] Refactor ilogbf implementation to header-only in src/__support/math folder. (PR #175522)
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libc-commits at lists.llvm.org
Mon Jan 12 03:56:49 PST 2026
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-libc
Author: Anonymous (YuXuan255)
<details>
<summary>Changes</summary>
closes #<!-- -->175347 , part of #<!-- -->175344
---
Full diff: https://github.com/llvm/llvm-project/pull/175522.diff
9 Files Affected:
- (modified) libc/shared/math.h (+1)
- (added) libc/shared/math/ilogbf.h (+24)
- (modified) libc/src/__support/math/CMakeLists.txt (+12-1)
- (added) libc/src/__support/math/ilogbf.h (+30)
- (modified) libc/src/math/generic/CMakeLists.txt (+1-1)
- (modified) libc/src/math/generic/ilogbf.cpp (+2-4)
- (modified) libc/test/shared/CMakeLists.txt (+1)
- (modified) libc/test/shared/shared_math_test.cpp (+2)
- (modified) utils/bazel/llvm-project-overlay/libc/BUILD.bazel (+17-1)
``````````diff
diff --git a/libc/shared/math.h b/libc/shared/math.h
index 287f3aea1565a..3ec41f52b51e4 100644
--- a/libc/shared/math.h
+++ b/libc/shared/math.h
@@ -60,6 +60,7 @@
#include "math/frexpf.h"
#include "math/frexpf128.h"
#include "math/frexpf16.h"
+#include "math/ilogbf.h"
#include "math/ilogbf16.h"
#include "math/ldexpf.h"
#include "math/ldexpf128.h"
diff --git a/libc/shared/math/ilogbf.h b/libc/shared/math/ilogbf.h
new file mode 100644
index 0000000000000..058c4082e0a9c
--- /dev/null
+++ b/libc/shared/math/ilogbf.h
@@ -0,0 +1,24 @@
+//===-- Shared ilogbf 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_ILOGBF_H
+#define LLVM_LIBC_SHARED_MATH_ILOGBF_H
+
+#include "include/llvm-libc-macros/float-macros.h"
+
+#include "src/__support/math/ilogbf.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::ilogbf;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_MATH_ILOGBF_H
diff --git a/libc/src/__support/math/CMakeLists.txt b/libc/src/__support/math/CMakeLists.txt
index 4139a1b1d3444..1f33b16bbcd1c 100644
--- a/libc/src/__support/math/CMakeLists.txt
+++ b/libc/src/__support/math/CMakeLists.txt
@@ -390,7 +390,6 @@ add_header_library(
cosf.h
DEPENDS
.sincosf_utils
- libc.src.errno.errno
libc.src.__support.FPUtil.basic_operations
libc.src.__support.FPUtil.fenv_impl
libc.src.__support.FPUtil.fp_bits
@@ -642,6 +641,18 @@ add_header_library(
libc.include.llvm-libc-macros.float16_macros
)
+add_header_library(
+ ilogbf
+ HDRS
+ ilogbf.h
+ DEPENDS
+ libc.src.__support.macros.config
+ libc.src.__support.macros.properties.types
+ libc.src.__support.FPUtil.manipulation_functions
+ libc.src.errno.errno
+ libc.include.llvm-libc-macros.float_macros
+)
+
add_header_library(
ldexpf128
HDRS
diff --git a/libc/src/__support/math/ilogbf.h b/libc/src/__support/math/ilogbf.h
new file mode 100644
index 0000000000000..94d6a71d96f47
--- /dev/null
+++ b/libc/src/__support/math/ilogbf.h
@@ -0,0 +1,30 @@
+//===-- Implementation header for ilogbf ----------------------*- 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_ILOGBF_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_ILOGBF_H
+
+#include "include/llvm-libc-macros/float-macros.h"
+
+#include "src/__support/FPUtil/ManipulationFunctions.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace math {
+
+LIBC_INLINE constexpr int ilogbf(float x) {
+ return fputil::intlogb<int>(x);
+}
+
+} // namespace math
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_ILOGBF_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 6de4cf376bf02..1ecbb38984549 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -1772,7 +1772,7 @@ add_entrypoint_object(
HDRS
../ilogbf.h
DEPENDS
- libc.src.__support.FPUtil.manipulation_functions
+ libc.src.__support.math.ilogbf
)
add_entrypoint_object(
diff --git a/libc/src/math/generic/ilogbf.cpp b/libc/src/math/generic/ilogbf.cpp
index 7da2aff3de316..0ed2cb569fd2e 100644
--- a/libc/src/math/generic/ilogbf.cpp
+++ b/libc/src/math/generic/ilogbf.cpp
@@ -7,12 +7,10 @@
//===----------------------------------------------------------------------===//
#include "src/math/ilogbf.h"
-#include "src/__support/FPUtil/ManipulationFunctions.h"
-#include "src/__support/common.h"
-#include "src/__support/macros/config.h"
+#include "src/__support/math/ilogbf.h"
namespace LIBC_NAMESPACE_DECL {
-LLVM_LIBC_FUNCTION(int, ilogbf, (float x)) { return fputil::intlogb<int>(x); }
+LLVM_LIBC_FUNCTION(int, ilogbf, (float x)) { return math::ilogbf(x); }
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/shared/CMakeLists.txt b/libc/test/shared/CMakeLists.txt
index c5955ecfd54cb..fb713189daf4a 100644
--- a/libc/test/shared/CMakeLists.txt
+++ b/libc/test/shared/CMakeLists.txt
@@ -56,6 +56,7 @@ add_fp_unittest(
libc.src.__support.math.frexpf
libc.src.__support.math.frexpf128
libc.src.__support.math.frexpf16
+ libc.src.__support.math.ilogbf
libc.src.__support.math.ilogbf16
libc.src.__support.math.log
libc.src.__support.math.ldexpf
diff --git a/libc/test/shared/shared_math_test.cpp b/libc/test/shared/shared_math_test.cpp
index 20a98a1a9138c..7c07b000ff4af 100644
--- a/libc/test/shared/shared_math_test.cpp
+++ b/libc/test/shared/shared_math_test.cpp
@@ -74,6 +74,8 @@ TEST(LlvmLibcSharedMathTest, AllFloat) {
LIBC_NAMESPACE::shared::frexpf(24.0f, &exponent));
EXPECT_EQ(exponent, 5);
+ EXPECT_EQ(0, LIBC_NAMESPACE::shared::ilogbf(1.0f));
+
ASSERT_FP_EQ(float(8 << 5), LIBC_NAMESPACE::shared::ldexpf(8.0f, 5));
ASSERT_FP_EQ(float(-1 * (8 << 5)), LIBC_NAMESPACE::shared::ldexpf(-8.0f, 5));
diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
index c03c21b834895..3008f3800cabf 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -2853,6 +2853,17 @@ libc_support_library(
],
)
+libc_support_library(
+ name = "__support_math_ilogbf",
+ hdrs = ["src/__support/math/ilogbf.h"],
+ deps = [
+ ":__support_common",
+ ":__support_fputil_manipulation_functions",
+ ":__support_macros_config",
+ ":llvm_libc_macros_float_macros",
+ ],
+)
+
libc_support_library(
name = "__support_math_ldexpf128",
hdrs = ["src/__support/math/ldexpf128.h"],
@@ -4332,7 +4343,12 @@ libc_math_function(
libc_math_function(name = "ilogb")
-libc_math_function(name = "ilogbf")
+libc_math_function(
+ name = "ilogbf",
+ additional_deps = [
+ ":__support_math_ilogbf",
+ ],
+)
libc_math_function(name = "ilogbl")
``````````
</details>
https://github.com/llvm/llvm-project/pull/175522
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