From d06e9ce1dd69d53a2a2afd06c027ca8af87a7d7e Mon Sep 17 00:00:00 2001
From: Muhammad Bassiouni <60100307+bassiounix@users.noreply.github.com>
Date: Sat, 12 Jul 2025 18:08:58 +0300
Subject: [PATCH] [libc][math] Refactor frexpf implementation to header-only in
 src/__support/math folder. (#147893)

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
---
 libc/shared/math.h                            |  1 +
 libc/shared/math/frexpf.h                     | 24 ++++++++++++++++
 libc/src/__support/math/CMakeLists.txt        |  8 ++++++
 libc/src/__support/math/frexpf.h              | 28 +++++++++++++++++++
 libc/src/math/generic/CMakeLists.txt          |  2 +-
 libc/src/math/generic/frexpf.cpp              |  7 ++---
 .../llvm-project-overlay/libc/BUILD.bazel     | 15 +++++++++-
 7 files changed, 79 insertions(+), 6 deletions(-)
 create mode 100644 libc/shared/math/frexpf.h
 create mode 100644 libc/src/__support/math/frexpf.h

diff --git a/libc/shared/math.h b/libc/shared/math.h
index 13c0f9abcdbd..e2950e075a81 100644
--- a/libc/shared/math.h
+++ b/libc/shared/math.h
@@ -13,6 +13,7 @@
 
 #include "math/expf.h"
 #include "math/expf16.h"
+#include "math/frexpf.h"
 #include "math/frexpf128.h"
 #include "math/frexpf16.h"
 
diff --git a/libc/shared/math/frexpf.h b/libc/shared/math/frexpf.h
new file mode 100644
index 000000000000..35f23a70eb25
--- /dev/null
+++ b/libc/shared/math/frexpf.h
@@ -0,0 +1,24 @@
+//===-- Shared frexpf 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_FREXPF_H
+#define LLVM_LIBC_SHARED_MATH_FREXPF_H
+
+#include "shared/libc_common.h"
+#include "src/__support/math/frexpf.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::frexpf;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_MATH_FREXPF_H
diff --git a/libc/src/__support/math/CMakeLists.txt b/libc/src/__support/math/CMakeLists.txt
index e745c07529ac..0baf12a26a9d 100644
--- a/libc/src/__support/math/CMakeLists.txt
+++ b/libc/src/__support/math/CMakeLists.txt
@@ -74,3 +74,11 @@ add_header_library(
     libc.src.__support.macros.properties.types
     libc.src.__support.FPUtil.manipulation_functions
 )
+
+add_header_library(
+  frexpf
+  HDRS
+    frexpf.h
+  DEPENDS
+    libc.src.__support.FPUtil.manipulation_functions
+)
diff --git a/libc/src/__support/math/frexpf.h b/libc/src/__support/math/frexpf.h
new file mode 100644
index 000000000000..4d2f4948f2af
--- /dev/null
+++ b/libc/src/__support/math/frexpf.h
@@ -0,0 +1,28 @@
+//===-- Implementation header for frexpf ------------------------*- 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_FREXPF_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_FREXPF_H
+
+#include "src/__support/FPUtil/ManipulationFunctions.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace math {
+
+static constexpr float frexpf(float x, int *exp) {
+  return fputil::frexp(x, *exp);
+}
+
+} // namespace math
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_FREXPF_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 6b540b2aafc9..60b8f83f6101 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -1759,7 +1759,7 @@ add_entrypoint_object(
   HDRS
     ../frexpf.h
   DEPENDS
-    libc.src.__support.FPUtil.manipulation_functions
+    libc.src.__support.math.frexpf
 )
 
 add_entrypoint_object(
diff --git a/libc/src/math/generic/frexpf.cpp b/libc/src/math/generic/frexpf.cpp
index 09227badc341..783880d44ce6 100644
--- a/libc/src/math/generic/frexpf.cpp
+++ b/libc/src/math/generic/frexpf.cpp
@@ -7,14 +7,13 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/math/frexpf.h"
-#include "src/__support/FPUtil/ManipulationFunctions.h"
-#include "src/__support/common.h"
-#include "src/__support/macros/config.h"
+
+#include "src/__support/math/frexpf.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(float, frexpf, (float x, int *exp)) {
-  return fputil::frexp(x, *exp);
+  return math::frexpf(x, exp);
 }
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
index 3b1d108109ed..11ea06897f82 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -2169,6 +2169,14 @@ libc_support_library(
     ],
 )
 
+libc_support_library(
+    name = "__support_math_frexpf",
+    hdrs = ["src/__support/math/frexpf.h"],
+    deps = [
+        ":__support_fputil_manipulation_functions",
+    ],
+)
+
 ############################### complex targets ################################
 
 libc_function(
@@ -3216,7 +3224,12 @@ libc_math_function(name = "fmulf128")
 
 libc_math_function(name = "frexp")
 
-libc_math_function(name = "frexpf")
+libc_math_function(
+    name = "frexpf",
+    additional_deps = [
+        ":__support_math_frexpf",
+    ],
+)
 
 libc_math_function(name = "frexpl")