[libc] add shared subdf3 builtin by hulxv · Pull Request #205673 · llvm/llvm-project

hulxv · 2026-06-24T21:01:59Z

Re-exposes LLVM-libc's __subdf3 as shared::subdf3 for reuse by compiler-rt's builtins.

Stacked change - merge these first:

Part of #197824

llvmorg-github-actions · 2026-06-24T21:52:19Z

@llvm/pr-subscribers-libc

Author: hulxv (hulxv)

Changes

Re-exposes LLVM-libc's __subdf3 as shared::subdf3 for reuse by compiler-rt's builtins.

Stacked change - merge these first:

#200094
#205669
#205670
#205671
#205672

Patch is 22.62 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/205673.diff

19 Files Affected:

(modified) libc/include/llvm-libc-macros/float-macros.h (+6)
(added) libc/shared/builtins.h (+27)
(added) libc/shared/builtins/adddf3.h (+29)
(added) libc/shared/builtins/addtf3.h (+35)
(added) libc/shared/builtins/divtf3.h (+35)
(added) libc/shared/builtins/multf3.h (+35)
(added) libc/shared/builtins/subdf3.h (+29)
(added) libc/shared/builtins/subtf3.h (+35)
(modified) libc/src/__support/CMakeLists.txt (+1)
(modified) libc/src/__support/FPUtil/dyadic_float.h (+3)
(added) libc/src/__support/builtins/CMakeLists.txt (+57)
(added) libc/src/__support/builtins/adddf3.h (+32)
(added) libc/src/__support/builtins/addtf3.h (+38)
(added) libc/src/__support/builtins/divtf3.h (+38)
(added) libc/src/__support/builtins/multf3.h (+38)
(added) libc/src/__support/builtins/subdf3.h (+32)
(added) libc/src/__support/builtins/subtf3.h (+38)
(modified) libc/test/shared/CMakeLists.txt (+10)
(added) libc/test/shared/shared_builtins_test.cpp (+71)

diff --git a/libc/include/llvm-libc-macros/float-macros.h b/libc/include/llvm-libc-macros/float-macros.h
index a25ef60a293d3..38a3a771cca54 100644
--- a/libc/include/llvm-libc-macros/float-macros.h
+++ b/libc/include/llvm-libc-macros/float-macros.h
@@ -9,6 +9,12 @@
 #ifndef LLVM_LIBC_MACROS_FLOAT_MACROS_H
 #define LLVM_LIBC_MACROS_FLOAT_MACROS_H
 
+// __has_builtin is a Clang extension; GCC < 10 doesn't define it, which
+// turns a bare `#if __has_builtin(...)` into a preprocessor syntax error.
+#ifndef __has_builtin
+#define __has_builtin(x) 0
+#endif
+
 #ifndef FLT_RADIX
 #define FLT_RADIX __FLT_RADIX__
 #endif // FLT_RADIX
diff --git a/libc/shared/builtins.h b/libc/shared/builtins.h
new file mode 100644
index 0000000000000..867bf6df0d306
--- /dev/null
+++ b/libc/shared/builtins.h
@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header aggregates LLVM-libc's shared compiler-rt builtins so that
+/// they can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SHARED_BUILTINS_H
+#define LLVM_LIBC_SHARED_BUILTINS_H
+
+#include "libc_common.h"
+
+#include "builtins/adddf3.h"
+#include "builtins/addtf3.h"
+#include "builtins/divtf3.h"
+#include "builtins/multf3.h"
+#include "builtins/subdf3.h"
+#include "builtins/subtf3.h"
+
+#endif // LLVM_LIBC_SHARED_BUILTINS_H
diff --git a/libc/shared/builtins/adddf3.h b/libc/shared/builtins/adddf3.h
new file mode 100644
index 0000000000000..33936cb8b2486
--- /dev/null
+++ b/libc/shared/builtins/adddf3.h
@@ -0,0 +1,29 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header exposes LLVM-libc's __adddf3 implementation as shared::adddf3 so
+/// that it can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SHARED_BUILTINS_ADDDF3_H
+#define LLVM_LIBC_SHARED_BUILTINS_ADDDF3_H
+
+#include "shared/libc_common.h"
+#include "src/__support/builtins/adddf3.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using builtins::adddf3;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_BUILTINS_ADDDF3_H
diff --git a/libc/shared/builtins/addtf3.h b/libc/shared/builtins/addtf3.h
new file mode 100644
index 0000000000000..33534beeb91c7
--- /dev/null
+++ b/libc/shared/builtins/addtf3.h
@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header exposes LLVM-libc's __addtf3 implementation as shared::addtf3
+/// so that it can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SHARED_BUILTINS_ADDTF3_H
+#define LLVM_LIBC_SHARED_BUILTINS_ADDTF3_H
+
+#include "include/llvm-libc-types/float128.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT128
+
+#include "shared/libc_common.h"
+#include "src/__support/builtins/addtf3.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using builtins::addtf3;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT128
+
+#endif // LLVM_LIBC_SHARED_BUILTINS_ADDTF3_H
diff --git a/libc/shared/builtins/divtf3.h b/libc/shared/builtins/divtf3.h
new file mode 100644
index 0000000000000..ca69e6f5fc0e7
--- /dev/null
+++ b/libc/shared/builtins/divtf3.h
@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header exposes LLVM-libc's __divtf3 implementation as shared::divtf3 so
+/// that it can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SHARED_BUILTINS_DIVTF3_H
+#define LLVM_LIBC_SHARED_BUILTINS_DIVTF3_H
+
+#include "include/llvm-libc-types/float128.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT128
+
+#include "shared/libc_common.h"
+#include "src/__support/builtins/divtf3.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using builtins::divtf3;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT128
+
+#endif // LLVM_LIBC_SHARED_BUILTINS_DIVTF3_H
diff --git a/libc/shared/builtins/multf3.h b/libc/shared/builtins/multf3.h
new file mode 100644
index 0000000000000..cfc2964fd6a79
--- /dev/null
+++ b/libc/shared/builtins/multf3.h
@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header exposes LLVM-libc's __multf3 implementation as shared::multf3 so
+/// that it can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SHARED_BUILTINS_MULTF3_H
+#define LLVM_LIBC_SHARED_BUILTINS_MULTF3_H
+
+#include "include/llvm-libc-types/float128.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT128
+
+#include "shared/libc_common.h"
+#include "src/__support/builtins/multf3.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using builtins::multf3;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT128
+
+#endif // LLVM_LIBC_SHARED_BUILTINS_MULTF3_H
diff --git a/libc/shared/builtins/subdf3.h b/libc/shared/builtins/subdf3.h
new file mode 100644
index 0000000000000..8cff7e3bfa28f
--- /dev/null
+++ b/libc/shared/builtins/subdf3.h
@@ -0,0 +1,29 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header exposes LLVM-libc's __subdf3 implementation as shared::subdf3 so
+/// that it can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SHARED_BUILTINS_SUBDF3_H
+#define LLVM_LIBC_SHARED_BUILTINS_SUBDF3_H
+
+#include "shared/libc_common.h"
+#include "src/__support/builtins/subdf3.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using builtins::subdf3;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_BUILTINS_SUBDF3_H
diff --git a/libc/shared/builtins/subtf3.h b/libc/shared/builtins/subtf3.h
new file mode 100644
index 0000000000000..a7cecef8b0479
--- /dev/null
+++ b/libc/shared/builtins/subtf3.h
@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header exposes LLVM-libc's __subtf3 implementation as shared::subtf3 so
+/// that it can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SHARED_BUILTINS_SUBTF3_H
+#define LLVM_LIBC_SHARED_BUILTINS_SUBTF3_H
+
+#include "include/llvm-libc-types/float128.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT128
+
+#include "shared/libc_common.h"
+#include "src/__support/builtins/subtf3.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using builtins::subtf3;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT128
+
+#endif // LLVM_LIBC_SHARED_BUILTINS_SUBTF3_H
diff --git a/libc/src/__support/CMakeLists.txt b/libc/src/__support/CMakeLists.txt
index 9d08b4bcf7303..c09ca012c3594 100644
--- a/libc/src/__support/CMakeLists.txt
+++ b/libc/src/__support/CMakeLists.txt
@@ -472,6 +472,7 @@ add_subdirectory(wchar)
 add_subdirectory(wctype)
 
 add_subdirectory(math)
+add_subdirectory(builtins)
 if(LIBC_COMPILER_HAS_EXT_VECTOR_TYPE)
   add_subdirectory(mathvec)
 endif()
diff --git a/libc/src/__support/FPUtil/dyadic_float.h b/libc/src/__support/FPUtil/dyadic_float.h
index 7e4ea2f1a81be..d99a14f35f38e 100644
--- a/libc/src/__support/FPUtil/dyadic_float.h
+++ b/libc/src/__support/FPUtil/dyadic_float.h
@@ -415,6 +415,9 @@ template <size_t Bits> struct DyadicFloat {
     if constexpr (cpp::is_same_v<T, bfloat16>
 #if defined(LIBC_TYPES_HAS_FLOAT16) && !defined(__LIBC_USE_FLOAT16_CONVERSION)
                   || cpp::is_same_v<T, float16>
+#endif
+#if defined(LIBC_TYPES_HAS_FLOAT128)
+                  || cpp::is_same_v<T, float128>
 #endif
     )
       return generic_as<T, ShouldSignalExceptions>();
diff --git a/libc/src/__support/builtins/CMakeLists.txt b/libc/src/__support/builtins/CMakeLists.txt
new file mode 100644
index 0000000000000..47dbc6cddbf68
--- /dev/null
+++ b/libc/src/__support/builtins/CMakeLists.txt
@@ -0,0 +1,57 @@
+add_header_library(
+  addtf3
+  HDRS
+    addtf3.h
+  DEPENDS
+    libc.include.llvm-libc-types.float128
+    libc.src.__support.FPUtil.generic.add_sub
+    libc.src.__support.macros.config
+)
+
+add_header_library(
+  subtf3
+  HDRS
+    subtf3.h
+  DEPENDS
+    libc.include.llvm-libc-types.float128
+    libc.src.__support.FPUtil.generic.add_sub
+    libc.src.__support.macros.config
+)
+
+add_header_library(
+  multf3
+  HDRS
+    multf3.h
+  DEPENDS
+    libc.include.llvm-libc-types.float128
+    libc.src.__support.FPUtil.generic.mul
+    libc.src.__support.macros.config
+)
+
+add_header_library(
+  divtf3
+  HDRS
+    divtf3.h
+  DEPENDS
+    libc.include.llvm-libc-types.float128
+    libc.src.__support.FPUtil.generic.div
+    libc.src.__support.macros.config
+)
+
+add_header_library(
+  adddf3
+  HDRS
+    adddf3.h
+  DEPENDS
+    libc.src.__support.FPUtil.generic.add_sub
+    libc.src.__support.macros.config
+)
+
+add_header_library(
+  subdf3
+  HDRS
+    subdf3.h
+  DEPENDS
+    libc.src.__support.FPUtil.generic.add_sub
+    libc.src.__support.macros.config
+)
diff --git a/libc/src/__support/builtins/adddf3.h b/libc/src/__support/builtins/adddf3.h
new file mode 100644
index 0000000000000..9fa60ca8d1c69
--- /dev/null
+++ b/libc/src/__support/builtins/adddf3.h
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header exposes LLVM-libc's __adddf3 implementation as builtins::adddf3
+/// so that it can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_BUILTINS_ADDDF3_H
+#define LLVM_LIBC_SRC___SUPPORT_BUILTINS_ADDDF3_H
+
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace builtins {
+
+// Addition at double precision; mirrors compiler-rt's __adddf3.
+LIBC_INLINE double adddf3(double x, double y) {
+  return fputil::generic::add<double>(x, y);
+}
+
+} // namespace builtins
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_BUILTINS_ADDDF3_H
diff --git a/libc/src/__support/builtins/addtf3.h b/libc/src/__support/builtins/addtf3.h
new file mode 100644
index 0000000000000..f33036f53ec30
--- /dev/null
+++ b/libc/src/__support/builtins/addtf3.h
@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header exposes LLVM-libc's __addtf3 implementation as
+/// builtins::addtf3 so that it can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_BUILTINS_ADDTF3_H
+#define LLVM_LIBC_SRC___SUPPORT_BUILTINS_ADDTF3_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 builtins {
+
+// Mirrors the compiler-rt __addtf3 ABI: a + b at float128 precision.
+LIBC_INLINE float128 addtf3(float128 x, float128 y) {
+  return fputil::generic::add<float128>(x, y);
+}
+
+} // namespace builtins
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT128
+
+#endif // LLVM_LIBC_SRC___SUPPORT_BUILTINS_ADDTF3_H
diff --git a/libc/src/__support/builtins/divtf3.h b/libc/src/__support/builtins/divtf3.h
new file mode 100644
index 0000000000000..7f25586cde6c9
--- /dev/null
+++ b/libc/src/__support/builtins/divtf3.h
@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header exposes LLVM-libc's __divtf3 implementation as builtins::divtf3
+/// so that it can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_BUILTINS_DIVTF3_H
+#define LLVM_LIBC_SRC___SUPPORT_BUILTINS_DIVTF3_H
+
+#include "include/llvm-libc-types/float128.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT128
+
+#include "src/__support/FPUtil/generic/div.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace builtins {
+
+// Division at float128 precision; mirrors compiler-rt's __divtf3.
+LIBC_INLINE float128 divtf3(float128 x, float128 y) {
+  return fputil::generic::div<float128>(x, y);
+}
+
+} // namespace builtins
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT128
+
+#endif // LLVM_LIBC_SRC___SUPPORT_BUILTINS_DIVTF3_H
diff --git a/libc/src/__support/builtins/multf3.h b/libc/src/__support/builtins/multf3.h
new file mode 100644
index 0000000000000..b6798325ff17d
--- /dev/null
+++ b/libc/src/__support/builtins/multf3.h
@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header exposes LLVM-libc's __multf3 implementation as builtins::multf3
+/// so that it can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_BUILTINS_MULTF3_H
+#define LLVM_LIBC_SRC___SUPPORT_BUILTINS_MULTF3_H
+
+#include "include/llvm-libc-types/float128.h"
+
+#ifdef LIBC_TYPES_HAS_FLOAT128
+
+#include "src/__support/FPUtil/generic/mul.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace builtins {
+
+// Multiplication at float128 precision; mirrors compiler-rt's __multf3.
+LIBC_INLINE float128 multf3(float128 x, float128 y) {
+  return fputil::generic::mul<float128>(x, y);
+}
+
+} // namespace builtins
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT128
+
+#endif // LLVM_LIBC_SRC___SUPPORT_BUILTINS_MULTF3_H
diff --git a/libc/src/__support/builtins/subdf3.h b/libc/src/__support/builtins/subdf3.h
new file mode 100644
index 0000000000000..5e704aa714af6
--- /dev/null
+++ b/libc/src/__support/builtins/subdf3.h
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header exposes LLVM-libc's __subdf3 implementation as builtins::subdf3
+/// so that it can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_BUILTINS_SUBDF3_H
+#define LLVM_LIBC_SRC___SUPPORT_BUILTINS_SUBDF3_H
+
+#include "src/__support/FPUtil/generic/add_sub.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace builtins {
+
+// Subtraction at double precision; mirrors compiler-rt's __subdf3.
+LIBC_INLINE double subdf3(double x, double y) {
+  return fputil::generic::sub<double>(x, y);
+}
+
+} // namespace builtins
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_BUILTINS_SUBDF3_H
diff --git a/libc/src/__support/builtins/subtf3.h b/libc/src/__support/builtins/subtf3.h
new file mode 100644
index 0000000000000..bd758cce0f5f6
--- /dev/null
+++ b/libc/src/__support/builtins/subtf3.h
@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header exposes LLVM-libc's __subtf3 implementation as builtins::subtf3
+/// so that it can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_BUILTINS_SUBTF3_H
+#define LLVM_LIBC_SRC___SUPPORT_BUILTINS_SUBTF3_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 builtins {
+
+// Subtraction at float128 precision; mirrors compiler-rt's __subtf3.
+LIBC_INLINE float128 subtf3(float128 x, float128 y) {
+  return fputil::generic::sub<float128>(x, y);
+}
+
+} // namespace builtins
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LIBC_TYPES_HAS_FLOAT128
+
+#endif // LLVM_LIBC_SRC___SUPPORT_BUILTINS_SUBTF3_H
diff --git a/libc/test/shared/CMakeLists.txt b/libc/test/shared/CMa...
[truncated]

github-actions · 2026-06-25T17:15:16Z

🪟 Windows x64 Test Results

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github-actions · 2026-06-25T17:15:16Z

🐧 Linux x64 Test Results

138035 tests passed
3201 tests skipped

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Re-exposes LLVM-libc's `__subdf3` as `shared::subdf3` for reuse by compiler-rt's builtins. Stacked change - merge these first: - llvm#200094 - llvm#205669 - llvm#205670 - llvm#205671 - llvm#205672 Part of llvm#197824

Re-exposes LLVM-libc's `__muldf3` as `shared::muldf3` for reuse by compiler-rt's builtins. Stacked change - merge these first: - #200094 - #205669 - #205670 - #205671 - #205672 - #205673 Part of #197824

Re-exposes LLVM-libc's `__subdf3` as `shared::subdf3` for reuse by compiler-rt's builtins. Stacked change - merge these first: - llvm#200094 - llvm#205669 - llvm#205670 - llvm#205671 - llvm#205672 Part of llvm#197824

Re-exposes LLVM-libc's `__muldf3` as `shared::muldf3` for reuse by compiler-rt's builtins. Stacked change - merge these first: - llvm#200094 - llvm#205669 - llvm#205670 - llvm#205671 - llvm#205672 - llvm#205673 Part of llvm#197824

Re-exposes LLVM-libc's `__divdf3` as `shared::divdf3` for reuse by compiler-rt's builtins. Stacked change - merge these first: - #200094 - #205669 - #205670 - #205671 - #205672 - #205673 - #205674 Part of #197824

Re-exposes LLVM-libc's `__addsf3` as `shared::addsf3` for reuse by compiler-rt's builtins. Stacked change - merge these first: - #200094 - #205669 - #205670 - #205671 - #205672 - #205673 - #205674 - #205675 Part of #197824

Re-exposes LLVM-libc's `__subsf3` as `shared::subsf3` for reuse by compiler-rt's builtins. Stacked change - merge these first: - #200094 - #205669 - #205670 - #205671 - #205672 - #205673 - #205674 - #205675 - #205676 Part of #197824

Re-exposes LLVM-libc's `__mulsf3` as `shared::mulsf3` for reuse by compiler-rt's builtins. Stacked change - merge these first: - #200094 - #205669 - #205670 - #205671 - #205672 - #205673 - #205674 - #205675 - #205676 - #205677 Part of #197824

Re-exposes LLVM-libc's `__mulsf3` as `shared::mulsf3` for reuse by compiler-rt's builtins. Stacked change - merge these first: - llvm#200094 - llvm#205669 - llvm#205670 - llvm#205671 - llvm#205672 - llvm#205673 - llvm#205674 - llvm#205675 - llvm#205676 - llvm#205677 Part of llvm#197824

Re-exposes LLVM-libc's `__divsf3` as `shared::divsf3` for reuse by compiler-rt's builtins. Stacked change - merge these first: - #200094 - #205669 - #205670 - #205671 - #205672 - #205673 - #205674 - #205675 - #205676 - #205677 - #205678 Part of #197824

Re-exposes LLVM-libc's `__subsf3` as `shared::subsf3` for reuse by compiler-rt's builtins. Stacked change - merge these first: - #200094 - #205669 - #205670 - #205671 - #205672 - #205673 - #205674 - #205675 - #205676 Part of #197824

Re-exposes LLVM-libc's `__mulsf3` as `shared::mulsf3` for reuse by compiler-rt's builtins. Stacked change - merge these first: - #200094 - #205669 - #205670 - #205671 - #205672 - #205673 - #205674 - #205675 - #205676 - #205677 Part of #197824

hulxv requested a review from a team as a code owner June 24, 2026 21:02

hulxv requested review from bassiounix, lntue and michaelrj-google June 24, 2026 21:02

llvmorg-github-actions Bot added the libc label Jun 24, 2026

hulxv force-pushed the libc/feat/builtins/subdf3 branch from ed03f24 to e4afe01 Compare June 25, 2026 16:17

bassiounix approved these changes Jun 26, 2026

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hulxv force-pushed the libc/feat/builtins/subdf3 branch from 9dc95a0 to 5f43ed0 Compare June 26, 2026 20:02

[libc] add shared subdf3 builtin

f33671a

hulxv force-pushed the libc/feat/builtins/subdf3 branch from 5f43ed0 to f33671a Compare June 28, 2026 00:21

hulxv enabled auto-merge (squash) June 28, 2026 00:22

hulxv merged commit 10e7761 into llvm:main Jun 28, 2026
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[libc] add shared subdf3 builtin - #205673

[libc] add shared subdf3 builtin#205673
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