[libc-commits] [libc] [llvm] init commit to refactor ffmaf128 into a header only, compiles locally… (PR #177873)

via libc-commits libc-commits at lists.llvm.org
Sun Jan 25 11:44:26 PST 2026 

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libc

Author: None (parthtyagi27)

<details>
<summary>Changes</summary>

Changes for refactoring ffmaf128 from this issue: [#<!-- -->175325 ](https://github.com/llvm/llvm-project/issues/175325)




---
Full diff: https://github.com/llvm/llvm-project/pull/177873.diff


9 Files Affected:

- (modified) libc/shared/math.h (+1) 
- (added) libc/shared/math/ffmaf128.h (+23) 
- (modified) libc/src/__support/math/CMakeLists.txt (+8) 
- (added) libc/src/__support/math/ffmaf128.h (+27) 
- (modified) libc/src/math/generic/CMakeLists.txt (+1-1) 
- (modified) libc/src/math/generic/ffmaf128.cpp (+6-5) 
- (modified) libc/test/shared/CMakeLists.txt (+1) 
- (modified) libc/test/shared/shared_math_test.cpp (+1) 
- (modified) utils/bazel/llvm-project-overlay/libc/BUILD.bazel (+9-1) 


``````````diff
diff --git a/libc/shared/math.h b/libc/shared/math.h
index 7fb4c43f509c4..22ad93765fd1a 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/ffmaf128.h"
 #include "math/ldexpf.h"
 #include "math/ldexpf128.h"
 #include "math/ldexpf16.h"
diff --git a/libc/shared/math/ffmaf128.h b/libc/shared/math/ffmaf128.h
new file mode 100644
index 0000000000000..f468312a8234f
--- /dev/null
+++ b/libc/shared/math/ffmaf128.h
@@ -0,0 +1,23 @@
+//===-- Shared ffmaf128 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_FFMAF128_H
+#define LLVM_LIBC_SHARED_MATH_FFMAF128_H
+
+#include "shared/libc_common.h"
+#include "src/__support/math/ffmaf128.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::ffmaf128;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_MATH_FFMAF128_H
diff --git a/libc/src/__support/math/CMakeLists.txt b/libc/src/__support/math/CMakeLists.txt
index 741da7432c94f..982c1333c41ac 100644
--- a/libc/src/__support/math/CMakeLists.txt
+++ b/libc/src/__support/math/CMakeLists.txt
@@ -594,6 +594,14 @@ add_header_library(
     libc.src.__support.math.exp10_float16_constants
 )
 
+add_header_library(
+  ffmaf128
+  HDRS
+    ffmaf128.h
+  DEPENDS
+    libc.src.__support.FPUtil.fma
+)
+
 add_header_library(
   frexpf128
   HDRS
diff --git a/libc/src/__support/math/ffmaf128.h b/libc/src/__support/math/ffmaf128.h
new file mode 100644
index 0000000000000..8c6fdd2690879
--- /dev/null
+++ b/libc/src/__support/math/ffmaf128.h
@@ -0,0 +1,27 @@
+//===-- Implementation header for ffmaf128 --------------------------*- 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_FFMAF128_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_FFMAF128_H
+
+#include "src/__support/FPUtil/FMA.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace math {
+
+LIBC_INLINE static constexpr float ffmaf128(float128 x, float128 y, float128 z) {
+  return fputil::fma<float>(x, y, z);
+}
+
+} // namespace math
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_FFMAF128_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 9c0da076b6cf0..7543ddee40a42 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -3438,7 +3438,7 @@ add_entrypoint_object(
     ../ffmaf128.h
   DEPENDS
     libc.src.__support.macros.properties.types
-    libc.src.__support.FPUtil.fma
+    libc.src.__support.math.ffmaf128
 )
 
 add_entrypoint_object(
diff --git a/libc/src/math/generic/ffmaf128.cpp b/libc/src/math/generic/ffmaf128.cpp
index 55da93020faf3..442ecd0bb73e6 100644
--- a/libc/src/math/generic/ffmaf128.cpp
+++ b/libc/src/math/generic/ffmaf128.cpp
@@ -7,14 +7,15 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/math/ffmaf128.h"
-#include "src/__support/FPUtil/FMA.h"
-#include "src/__support/common.h"
-#include "src/__support/macros/config.h"
-
+// #include "src/__support/FPUtil/FMA.h"
+// #include "src/__support/common.h"
+// #include "src/__support/macros/config.h"
+#include "src/__support/math/ffmaf128.h"
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(float, ffmaf128, (float128 x, float128 y, float128 z)) {
-  return fputil::fma<float>(x, y, z);
+  // return fputil::fma<float>(x, y, z);
+    return math::ffmaf128(x, y, z);
 }
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/shared/CMakeLists.txt b/libc/test/shared/CMakeLists.txt
index 0f23162798a8b..cfa0c744e75bc 100644
--- a/libc/test/shared/CMakeLists.txt
+++ b/libc/test/shared/CMakeLists.txt
@@ -53,6 +53,7 @@ add_fp_unittest(
     libc.src.__support.math.exp10f16
     libc.src.__support.math.expf
     libc.src.__support.math.expf16
+    libc.src.__support.math.ffmaf128
     libc.src.__support.math.frexpf
     libc.src.__support.math.frexpf128
     libc.src.__support.math.frexpf16
diff --git a/libc/test/shared/shared_math_test.cpp b/libc/test/shared/shared_math_test.cpp
index f823d414e2afd..8103bfac3ee42 100644
--- a/libc/test/shared/shared_math_test.cpp
+++ b/libc/test/shared/shared_math_test.cpp
@@ -108,6 +108,7 @@ TEST(LlvmLibcSharedMathTest, AllFloat128) {
                LIBC_NAMESPACE::shared::ldexpf128(float128(8), 5));
   ASSERT_FP_EQ(float128(-1 * (8 << 5)),
                LIBC_NAMESPACE::shared::ldexpf128(float128(-8), 5));
+  EXPECT_FP_EQ(0x0p+0, LIBC_NAMESPACE::shared::ffmaf128(float128(0.0), float128(0.0), float128(0.0)));
 }
 
 #endif // LIBC_TYPES_HAS_FLOAT128
diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
index 210c25dddd0b9..f1e8f1a17d4f2 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -2804,6 +2804,14 @@ libc_support_library(
     ],
 )
 
+libc_support_library(
+    name = "__support_math_ffmaf128",
+    hdrs = ["src/__support/math/ffmaf128.h"],
+    deps = [
+        ":__support_macros_properties_types",
+    ],
+)
+
 libc_support_library(
     name = "__support_math_frexpf128",
     hdrs = ["src/__support/math/frexpf128.h"],
@@ -4013,7 +4021,7 @@ libc_math_function(
 libc_math_function(
     name = "ffmaf128",
     additional_deps = [
-        ":__support_fputil_fma",
+        ":__support_math_ffmaf128",
     ],
 )
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/177873

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