[libc-commits] [libc] [llvm] [libc][math] Refactor bf16sub family to header-only (PR #182115)
Mohamed Emad via libc-commits
libc-commits at lists.llvm.org
Wed Feb 18 11:55:54 PST 2026
https://github.com/hulxv created https://github.com/llvm/llvm-project/pull/182115
Refactors the bf16sub math family to be header-only.
Closes https://github.com/llvm/llvm-project/issues/182114
Target Functions:
- bf16sub
- bf16subf
- bf16subf128
>From 7c60ab51b7048c46e6e5e71e7f760a292a85edd7 Mon Sep 17 00:00:00 2001
From: hulxv <hulxxv at gmail.com>
Date: Wed, 18 Feb 2026 21:55:38 +0200
Subject: [PATCH] [libc][math] Refactor bf16sub family to header-only
Refactored functions:
- bf16sub
- bf16subf
- bf16subf128
---
libc/shared/math.h | 3 ++
libc/shared/math/bf16sub.h | 22 +++++++++
libc/shared/math/bf16subf.h | 22 +++++++++
libc/shared/math/bf16subf128.h | 28 +++++++++++
libc/src/__support/math/CMakeLists.txt | 28 +++++++++++
libc/src/__support/math/bf16sub.h | 27 +++++++++++
libc/src/__support/math/bf16subf.h | 27 +++++++++++
libc/src/__support/math/bf16subf128.h | 33 +++++++++++++
libc/src/math/generic/CMakeLists.txt | 18 ++------
libc/src/math/generic/bf16sub.cpp | 7 +--
libc/src/math/generic/bf16subf.cpp | 7 +--
libc/src/math/generic/bf16subf128.cpp | 7 +--
libc/test/shared/CMakeLists.txt | 3 ++
libc/test/shared/shared_math_test.cpp | 7 +++
.../llvm-project-overlay/libc/BUILD.bazel | 46 +++++++++++++++++++
15 files changed, 255 insertions(+), 30 deletions(-)
create mode 100644 libc/shared/math/bf16sub.h
create mode 100644 libc/shared/math/bf16subf.h
create mode 100644 libc/shared/math/bf16subf128.h
create mode 100644 libc/src/__support/math/bf16sub.h
create mode 100644 libc/src/__support/math/bf16subf.h
create mode 100644 libc/src/__support/math/bf16subf128.h
diff --git a/libc/shared/math.h b/libc/shared/math.h
index 8a5aca82c6ec3..00f57b1311dca 100644
--- a/libc/shared/math.h
+++ b/libc/shared/math.h
@@ -37,6 +37,9 @@
#include "math/bf16divl.h"
#include "math/bf16fmaf.h"
#include "math/bf16fmal.h"
+#include "math/bf16sub.h"
+#include "math/bf16subf.h"
+#include "math/bf16subf128.h"
#include "math/canonicalize.h"
#include "math/canonicalizebf16.h"
#include "math/canonicalizef.h"
diff --git a/libc/shared/math/bf16sub.h b/libc/shared/math/bf16sub.h
new file mode 100644
index 0000000000000..1ead52bbf04ef
--- /dev/null
+++ b/libc/shared/math/bf16sub.h
@@ -0,0 +1,22 @@
+//===-- Shared bf16sub 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_BF16SUB_H
+#define LLVM_LIBC_SHARED_MATH_BF16SUB_H
+
+#include "src/__support/math/bf16sub.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::bf16sub;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_MATH_BF16SUB_H
diff --git a/libc/shared/math/bf16subf.h b/libc/shared/math/bf16subf.h
new file mode 100644
index 0000000000000..b3078b5fe3564
--- /dev/null
+++ b/libc/shared/math/bf16subf.h
@@ -0,0 +1,22 @@
+//===-- Shared bf16subf 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_BF16SUBF_H
+#define LLVM_LIBC_SHARED_MATH_BF16SUBF_H
+
+#include "src/__support/math/bf16subf.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::bf16subf;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_MATH_BF16SUBF_H
diff --git a/libc/shared/math/bf16subf128.h b/libc/shared/math/bf16subf128.h
new file mode 100644
index 0000000000000..e238fc3739f1b
--- /dev/null
+++ b/libc/shared/math/bf16subf128.h
@@ -0,0 +1,28 @@
+//===-- Shared bf16subf128 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_BF16SUBF128_H
+#define LLVM_LIBC_SHARED_MATH_BF16SUBF128_H
+
+#include "include/llvm-libc-types/float128.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT128
+
+#include "src/__support/math/bf16subf128.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::bf16subf128;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT128
+
+#endif // LLVM_LIBC_SHARED_MATH_BF16SUBF128_H
diff --git a/libc/src/__support/math/CMakeLists.txt b/libc/src/__support/math/CMakeLists.txt
index e21fe8ef0ab93..488166d1ae172 100644
--- a/libc/src/__support/math/CMakeLists.txt
+++ b/libc/src/__support/math/CMakeLists.txt
@@ -381,6 +381,34 @@ add_header_library(
libc.src.__support.FPUtil.fma
libc.src.__support.macros.config
)
+add_header_library(
+ bf16sub
+ HDRS
+ bf16sub.h
+ DEPENDS
+ libc.src.__support.FPUtil.bfloat16
+ libc.src.__support.FPUtil.generic.add_sub
+ libc.src.__support.macros.config
+)
+add_header_library(
+ bf16subf
+ HDRS
+ bf16subf.h
+ DEPENDS
+ libc.src.__support.FPUtil.bfloat16
+ libc.src.__support.FPUtil.generic.add_sub
+ libc.src.__support.macros.config
+)
+add_header_library(
+ bf16subf128
+ HDRS
+ bf16subf128.h
+ DEPENDS
+ libc.include.llvm-libc-types.float128
+ libc.src.__support.FPUtil.bfloat16
+ libc.src.__support.FPUtil.generic.add_sub
+ libc.src.__support.macros.config
+)
add_header_library(
canonicalize
diff --git a/libc/src/__support/math/bf16sub.h b/libc/src/__support/math/bf16sub.h
new file mode 100644
index 0000000000000..a6aa1dfd6e652
--- /dev/null
+++ b/libc/src/__support/math/bf16sub.h
@@ -0,0 +1,27 @@
+//===-- Implementation header for bf16sub -----------------------*- 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_BF16SUB_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_BF16SUB_H
+
+#include "src/__support/FPUtil/bfloat16.h"
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace math {
+
+LIBC_INLINE bfloat16 bf16sub(double x, double y) {
+ return fputil::generic::sub<bfloat16>(x, y);
+}
+
+} // namespace math
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_BF16SUB_H
diff --git a/libc/src/__support/math/bf16subf.h b/libc/src/__support/math/bf16subf.h
new file mode 100644
index 0000000000000..347626f3eaf11
--- /dev/null
+++ b/libc/src/__support/math/bf16subf.h
@@ -0,0 +1,27 @@
+//===-- Implementation header for bf16subf ----------------------*- 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_BF16SUBF_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_BF16SUBF_H
+
+#include "src/__support/FPUtil/bfloat16.h"
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace math {
+
+LIBC_INLINE bfloat16 bf16subf(float x, float y) {
+ return fputil::generic::sub<bfloat16>(x, y);
+}
+
+} // namespace math
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_BF16SUBF_H
diff --git a/libc/src/__support/math/bf16subf128.h b/libc/src/__support/math/bf16subf128.h
new file mode 100644
index 0000000000000..51e42118451c9
--- /dev/null
+++ b/libc/src/__support/math/bf16subf128.h
@@ -0,0 +1,33 @@
+//===-- Implementation header for bf16subf128 -------------------*- 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_BF16SUBF128_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_BF16SUBF128_H
+
+#include "include/llvm-libc-types/float128.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT128
+
+#include "src/__support/FPUtil/bfloat16.h"
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace math {
+
+LIBC_INLINE bfloat16 bf16subf128(float128 x, float128 y) {
+ return fputil::generic::sub<bfloat16>(x, y);
+}
+
+} // namespace math
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT128
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_BF16SUBF128_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 57a29665318a3..766af65517124 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -5299,11 +5299,7 @@ add_entrypoint_object(
HDRS
../bf16sub.h
DEPENDS
- libc.src.__support.common
- libc.src.__support.FPUtil.bfloat16
- libc.src.__support.FPUtil.generic.add_sub
- libc.src.__support.macros.config
- libc.src.__support.macros.properties.types
+ libc.src.__support.math.bf16sub
)
add_entrypoint_object(
@@ -5313,11 +5309,7 @@ add_entrypoint_object(
HDRS
../bf16subf.h
DEPENDS
- libc.src.__support.common
- libc.src.__support.FPUtil.bfloat16
- libc.src.__support.FPUtil.generic.add_sub
- libc.src.__support.macros.config
- libc.src.__support.macros.properties.types
+ libc.src.__support.math.bf16subf
)
add_entrypoint_object(
@@ -5341,9 +5333,5 @@ add_entrypoint_object(
HDRS
../bf16subf128.h
DEPENDS
- libc.src.__support.common
- libc.src.__support.FPUtil.bfloat16
- libc.src.__support.FPUtil.generic.add_sub
- libc.src.__support.macros.config
- libc.src.__support.macros.properties.types
+ libc.src.__support.math.bf16subf128
)
diff --git a/libc/src/math/generic/bf16sub.cpp b/libc/src/math/generic/bf16sub.cpp
index 65eb2095dd4e9..7a3debe694940 100644
--- a/libc/src/math/generic/bf16sub.cpp
+++ b/libc/src/math/generic/bf16sub.cpp
@@ -7,15 +7,12 @@
//===----------------------------------------------------------------------===//
#include "src/math/bf16sub.h"
-#include "src/__support/FPUtil/bfloat16.h"
-#include "src/__support/FPUtil/generic/add_sub.h"
-#include "src/__support/common.h"
-#include "src/__support/macros/config.h"
+#include "src/__support/math/bf16sub.h"
namespace LIBC_NAMESPACE_DECL {
LLVM_LIBC_FUNCTION(bfloat16, bf16sub, (double x, double y)) {
- return fputil::generic::sub<bfloat16>(x, y);
+ return math::bf16sub(x, y);
}
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/math/generic/bf16subf.cpp b/libc/src/math/generic/bf16subf.cpp
index 6bba4be441be6..34692a489fa9c 100644
--- a/libc/src/math/generic/bf16subf.cpp
+++ b/libc/src/math/generic/bf16subf.cpp
@@ -7,15 +7,12 @@
//===----------------------------------------------------------------------===//
#include "src/math/bf16subf.h"
-#include "src/__support/FPUtil/bfloat16.h"
-#include "src/__support/FPUtil/generic/add_sub.h"
-#include "src/__support/common.h"
-#include "src/__support/macros/config.h"
+#include "src/__support/math/bf16subf.h"
namespace LIBC_NAMESPACE_DECL {
LLVM_LIBC_FUNCTION(bfloat16, bf16subf, (float x, float y)) {
- return fputil::generic::sub<bfloat16>(x, y);
+ return math::bf16subf(x, y);
}
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/math/generic/bf16subf128.cpp b/libc/src/math/generic/bf16subf128.cpp
index e5fe1077f89a7..4f66d761de7e8 100644
--- a/libc/src/math/generic/bf16subf128.cpp
+++ b/libc/src/math/generic/bf16subf128.cpp
@@ -7,15 +7,12 @@
//===----------------------------------------------------------------------===//
#include "src/math/bf16subf128.h"
-#include "src/__support/FPUtil/bfloat16.h"
-#include "src/__support/FPUtil/generic/add_sub.h"
-#include "src/__support/common.h"
-#include "src/__support/macros/config.h"
+#include "src/__support/math/bf16subf128.h"
namespace LIBC_NAMESPACE_DECL {
LLVM_LIBC_FUNCTION(bfloat16, bf16subf128, (float128 x, float128 y)) {
- return fputil::generic::sub<bfloat16>(x, y);
+ return math::bf16subf128(x, y);
}
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/shared/CMakeLists.txt b/libc/test/shared/CMakeLists.txt
index 53ad309af4f30..bbeed90030bac 100644
--- a/libc/test/shared/CMakeLists.txt
+++ b/libc/test/shared/CMakeLists.txt
@@ -33,6 +33,9 @@ add_fp_unittest(
libc.src.__support.math.bf16divl
libc.src.__support.math.bf16fmaf
libc.src.__support.math.bf16fmal
+ libc.src.__support.math.bf16sub
+ libc.src.__support.math.bf16subf
+ libc.src.__support.math.bf16subf128
libc.src.__support.math.canonicalize
libc.src.__support.math.canonicalizebf16
libc.src.__support.math.canonicalizef
diff --git a/libc/test/shared/shared_math_test.cpp b/libc/test/shared/shared_math_test.cpp
index 7f2f39ac7a285..e7c88cc1d1258 100644
--- a/libc/test/shared/shared_math_test.cpp
+++ b/libc/test/shared/shared_math_test.cpp
@@ -150,6 +150,8 @@ TEST(LlvmLibcSharedMathTest, AllFloat) {
EXPECT_EQ(0, LIBC_NAMESPACE::shared::canonicalizef(&canonicalizef_cx,
&canonicalizef_x));
EXPECT_FP_EQ(0x0p+0f, canonicalizef_cx);
+
+ EXPECT_FP_EQ(bfloat16(0.0), LIBC_NAMESPACE::shared::bf16subf(0.0f, 0.0f));
}
TEST(LlvmLibcSharedMathTest, AllDouble) {
@@ -187,6 +189,8 @@ TEST(LlvmLibcSharedMathTest, AllDouble) {
EXPECT_EQ(0, LIBC_NAMESPACE::shared::canonicalize(&canonicalize_cx,
&canonicalize_x));
EXPECT_FP_EQ(0.0, canonicalize_cx);
+
+ EXPECT_FP_EQ(bfloat16(0.0), LIBC_NAMESPACE::shared::bf16sub(0.0, 0.0));
}
TEST(LlvmLibcSharedMathTest, AllLongDouble) {
@@ -238,6 +242,9 @@ 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(bfloat16(0.0), LIBC_NAMESPACE::shared::bf16subf128(
+ 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..a53720269a3ea 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -2695,6 +2695,37 @@ libc_support_library(
],
)
+libc_support_library(
+ name = "__support_math_bf16sub",
+ hdrs = ["src/__support/math/bf16sub.h"],
+ deps = [
+ ":__support_fputil_basic_operations",
+ ":__support_fputil_bfloat16",
+ ":__support_macros_config",
+ ],
+)
+
+libc_support_library(
+ name = "__support_math_bf16subf",
+ hdrs = ["src/__support/math/bf16subf.h"],
+ deps = [
+ ":__support_fputil_basic_operations",
+ ":__support_fputil_bfloat16",
+ ":__support_macros_config",
+ ],
+)
+
+libc_support_library(
+ name = "__support_math_bf16subf128",
+ hdrs = ["src/__support/math/bf16subf128.h"],
+ deps = [
+ ":__support_fputil_basic_operations",
+ ":__support_fputil_bfloat16",
+ ":__support_macros_config",
+ ":llvm_libc_types_float128",
+ ],
+)
+
libc_support_library(
name = "__support_math_bf16fmal",
hdrs = ["src/__support/math/bf16fmal.h"],
@@ -4593,6 +4624,21 @@ libc_math_function(
additional_deps = [":__support_math_bf16divl"],
)
+libc_math_function(
+ name = "bf16sub",
+ additional_deps = [":__support_math_bf16sub"],
+)
+
+libc_math_function(
+ name = "bf16subf",
+ additional_deps = [":__support_math_bf16subf"],
+)
+
+libc_math_function(
+ name = "bf16subf128",
+ additional_deps = [":__support_math_bf16sub128"],
+)
+
libc_math_function(
name = "bf16fmaf",
additional_deps = [":__support_math_bf16fmaf"],
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