[libc-commits] [libc] [llvm] [libc][math] Refactor dsub family to header-only (PR #182160)

via libc-commits libc-commits at lists.llvm.org
Wed Feb 18 13:57:27 PST 2026


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libc

Author: Mohamed Emad (hulxv)

<details>
<summary>Changes</summary>

Refactors the dsub math family to be header-only.

Closes https://github.com/llvm/llvm-project/issues/182159

Target Functions:
  - dsubf128
  - dsubl

---
Full diff: https://github.com/llvm/llvm-project/pull/182160.diff


12 Files Affected:

- (modified) libc/shared/math.h (+2) 
- (added) libc/shared/math/dsubf128.h (+28) 
- (added) libc/shared/math/dsubl.h (+22) 
- (modified) libc/src/__support/math/CMakeLists.txt (+17) 
- (added) libc/src/__support/math/dsubf128.h (+32) 
- (added) libc/src/__support/math/dsubl.h (+26) 
- (modified) libc/src/math/generic/CMakeLists.txt (+2-3) 
- (modified) libc/src/math/generic/dsubf128.cpp (+2-4) 
- (modified) libc/src/math/generic/dsubl.cpp (+2-4) 
- (modified) libc/test/shared/CMakeLists.txt (+2) 
- (modified) libc/test/shared/shared_math_test.cpp (+5) 
- (modified) utils/bazel/llvm-project-overlay/libc/BUILD.bazel (+31-2) 


``````````diff
diff --git a/libc/shared/math.h b/libc/shared/math.h
index 8a5aca82c6ec3..7fea2537c4858 100644
--- a/libc/shared/math.h
+++ b/libc/shared/math.h
@@ -55,6 +55,8 @@
 #include "math/dfmaf128.h"
 #include "math/dfmal.h"
 #include "math/dsqrtl.h"
+#include "math/dsubf128.h"
+#include "math/dsubl.h"
 #include "math/erff.h"
 #include "math/exp.h"
 #include "math/exp10.h"
diff --git a/libc/shared/math/dsubf128.h b/libc/shared/math/dsubf128.h
new file mode 100644
index 0000000000000..4d401ddf023dc
--- /dev/null
+++ b/libc/shared/math/dsubf128.h
@@ -0,0 +1,28 @@
+//===-- Shared dsubf128 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_DSUBF128_H
+#define LLVM_LIBC_SHARED_MATH_DSUBF128_H
+
+#include "include/llvm-libc-types/float128.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT128
+
+#include "src/__support/math/dsubf128.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::dsubf128;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT128
+
+#endif // LLVM_LIBC_SHARED_MATH_DSUBF128_H
diff --git a/libc/shared/math/dsubl.h b/libc/shared/math/dsubl.h
new file mode 100644
index 0000000000000..a9b4fe5091ab4
--- /dev/null
+++ b/libc/shared/math/dsubl.h
@@ -0,0 +1,22 @@
+//===-- Shared dsubl 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_DSUBL_H
+#define LLVM_LIBC_SHARED_MATH_DSUBL_H
+
+#include "src/__support/math/dsubl.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::dsubl;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_MATH_DSUBL_H
diff --git a/libc/src/__support/math/CMakeLists.txt b/libc/src/__support/math/CMakeLists.txt
index e21fe8ef0ab93..d55f0887c34fd 100644
--- a/libc/src/__support/math/CMakeLists.txt
+++ b/libc/src/__support/math/CMakeLists.txt
@@ -591,6 +591,23 @@ add_header_library(
   DEPENDS
     libc.src.__support.FPUtil.generic.sqrt
 )
+add_header_library(
+  dsubf128
+  HDRS
+    dsubf128.h
+  DEPENDS
+    libc.include.llvm-libc-types.float128
+    libc.src.__support.FPUtil.generic.add_sub
+    libc.src.__support.macros.config
+)
+add_header_library(
+  dsubl
+  HDRS
+    dsubl.h
+  DEPENDS
+    libc.src.__support.FPUtil.generic.add_sub
+    libc.src.__support.macros.config
+)
 
 add_header_library(
   exp10m1f
diff --git a/libc/src/__support/math/dsubf128.h b/libc/src/__support/math/dsubf128.h
new file mode 100644
index 0000000000000..ed22808d4efe5
--- /dev/null
+++ b/libc/src/__support/math/dsubf128.h
@@ -0,0 +1,32 @@
+//===-- Implementation header for dsubf128 ----------------------*- 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_DSUBF128_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_DSUBF128_H
+
+#include "include/llvm-libc-types/float128.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT128
+
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace math {
+
+LIBC_INLINE double dsubf128(float128 x, float128 y) {
+  return fputil::generic::sub<double>(x, y);
+}
+
+} // namespace math
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT128
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_DSUBF128_H
diff --git a/libc/src/__support/math/dsubl.h b/libc/src/__support/math/dsubl.h
new file mode 100644
index 0000000000000..ef46ab3444ee7
--- /dev/null
+++ b/libc/src/__support/math/dsubl.h
@@ -0,0 +1,26 @@
+//===-- Implementation header for dsubl -------------------------*- 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_DSUBL_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_DSUBL_H
+
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace math {
+
+LIBC_INLINE double dsubl(long double x, long double y) {
+  return fputil::generic::sub<double>(x, y);
+}
+
+} // namespace math
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_DSUBL_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 57a29665318a3..a6d42145e0dda 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -285,8 +285,7 @@ add_entrypoint_object(
   HDRS
     ../dsubf128.h
   DEPENDS
-    libc.src.__support.FPUtil.generic.add_sub
-    libc.src.__support.macros.properties.types
+    libc.src.__support.math.dsubf128
 )
 
 add_entrypoint_object(
@@ -296,7 +295,7 @@ add_entrypoint_object(
   HDRS
     ../dsubl.h
   DEPENDS
-    libc.src.__support.FPUtil.generic.add_sub
+    libc.src.__support.math.dsubl
 )
 
 add_entrypoint_object(
diff --git a/libc/src/math/generic/dsubf128.cpp b/libc/src/math/generic/dsubf128.cpp
index 1b2f1214b3a6f..81510246b8b34 100644
--- a/libc/src/math/generic/dsubf128.cpp
+++ b/libc/src/math/generic/dsubf128.cpp
@@ -7,14 +7,12 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/math/dsubf128.h"
-#include "src/__support/FPUtil/generic/add_sub.h"
-#include "src/__support/common.h"
-#include "src/__support/macros/config.h"
+#include "src/__support/math/dsubf128.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(double, dsubf128, (float128 x, float128 y)) {
-  return fputil::generic::sub<double>(x, y);
+  return math::dsubf128(x, y);
 }
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/math/generic/dsubl.cpp b/libc/src/math/generic/dsubl.cpp
index 8b567d0869d2a..27b24bb8c0c7d 100644
--- a/libc/src/math/generic/dsubl.cpp
+++ b/libc/src/math/generic/dsubl.cpp
@@ -7,14 +7,12 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/math/dsubl.h"
-#include "src/__support/FPUtil/generic/add_sub.h"
-#include "src/__support/common.h"
-#include "src/__support/macros/config.h"
+#include "src/__support/math/dsubl.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(double, dsubl, (long double x, long double y)) {
-  return fputil::generic::sub<double>(x, y);
+  return math::dsubl(x, y);
 }
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/shared/CMakeLists.txt b/libc/test/shared/CMakeLists.txt
index 53ad309af4f30..4143b2ffcd77c 100644
--- a/libc/test/shared/CMakeLists.txt
+++ b/libc/test/shared/CMakeLists.txt
@@ -51,6 +51,8 @@ add_fp_unittest(
     libc.src.__support.math.dfmaf128
     libc.src.__support.math.dfmal
     libc.src.__support.math.dsqrtl
+    libc.src.__support.math.dsubf128
+    libc.src.__support.math.dsubl
     libc.src.__support.math.exp10m1f
     libc.src.__support.math.exp10m1f16
     libc.src.__support.math.erff
diff --git a/libc/test/shared/shared_math_test.cpp b/libc/test/shared/shared_math_test.cpp
index 7f2f39ac7a285..d013acc8401fb 100644
--- a/libc/test/shared/shared_math_test.cpp
+++ b/libc/test/shared/shared_math_test.cpp
@@ -203,6 +203,8 @@ TEST(LlvmLibcSharedMathTest, AllLongDouble) {
   EXPECT_EQ(0, LIBC_NAMESPACE::shared::canonicalizel(&canonicalizel_cx,
                                                      &canonicalizel_x));
   EXPECT_FP_EQ(0x0p+0L, canonicalizel_cx);
+
+  EXPECT_FP_EQ(0x0p+0L, LIBC_NAMESPACE::shared::dsubl(0.0L, 0.0L));
 }
 
 #ifdef LIBC_TYPES_HAS_FLOAT128
@@ -238,6 +240,9 @@ TEST(LlvmLibcSharedMathTest, AllFloat128) {
   EXPECT_EQ(0, LIBC_NAMESPACE::shared::canonicalizef128(&canonicalizef128_cx,
                                                         &canonicalizef128_x));
   EXPECT_FP_EQ(float128(0.0), canonicalizef128_cx);
+
+  EXPECT_FP_EQ(float128(0.0),
+               LIBC_NAMESPACE::shared::dsubf128(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 b90688af7a1d2..17ed97cb225f9 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -2896,6 +2896,25 @@ libc_support_library(
     ],
 )
 
+libc_support_library(
+    name = "__support_math_dsubf128",
+    hdrs = ["src/__support/math/dsubf128.h"],
+    deps = [
+        ":__support_fputil_basic_operations",
+        ":__support_macros_config",
+        ":llvm_libc_types_float128",
+    ],
+)
+
+libc_support_library(
+    name = "__support_math_dsubl",
+    hdrs = ["src/__support/math/dsubl.h"],
+    deps = [
+        ":__support_fputil_basic_operations",
+        ":__support_macros_config",
+    ],
+)
+
 libc_support_library(
     name = "__support_math_exp10m1f",
     hdrs = ["src/__support/math/exp10m1f.h"],
@@ -4765,9 +4784,19 @@ libc_math_function(
     additional_deps = [":__support_fputil_sqrt"],
 )
 
-libc_math_function(name = "dsubl")
+libc_math_function(
+    name = "dsubl",
+    additional_deps = [
+        ":__support_math_dsubl",
+    ],
+)
 
-libc_math_function(name = "dsubf128")
+libc_math_function(
+    name = "dsubf128",
+    additional_deps = [
+        ":__support_math_dsubf128",
+    ],
+)
 
 libc_math_function(
     name = "erff",

``````````

</details>


https://github.com/llvm/llvm-project/pull/182160


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