[libc-commits] [libc] [llvm] [libc] Modify `truncf128` to use emulated Float128 type (PR #216560)

via libc-commits libc-commits at lists.llvm.org
Fri Aug 21 02:45:57 PDT 2026


https://github.com/Sukumarsawant updated https://github.com/llvm/llvm-project/pull/216560

>From df17eac61f0a8a9c6c4706595a36f501bbbc4161 Mon Sep 17 00:00:00 2001
From: Sukumarsawant <sawantsukumar at gmail.com>
Date: Sun, 16 Aug 2026 16:28:54 +0530
Subject: [PATCH 1/3] intial commit

---
 libc/config/baremetal/aarch64/entrypoints.txt   |  2 +-
 libc/config/baremetal/arm/entrypoints.txt       |  2 +-
 libc/config/baremetal/riscv/entrypoints.txt     |  2 +-
 libc/config/darwin/aarch64/entrypoints.txt      |  2 +-
 libc/config/darwin/x86_64/entrypoints.txt       |  1 +
 libc/config/freebsd/x86_64/entrypoints.txt      |  2 +-
 libc/config/gpu/amdgpu/entrypoints.txt          |  1 +
 libc/config/gpu/nvptx/entrypoints.txt           |  1 +
 libc/config/linux/aarch64/entrypoints.txt       |  2 +-
 libc/config/linux/arm/entrypoints.txt           |  1 +
 libc/config/linux/riscv/entrypoints.txt         |  2 +-
 libc/config/linux/x86_64/entrypoints.txt        |  2 +-
 libc/config/windows/entrypoints.txt             |  1 +
 libc/shared/math/truncf128.h                    |  6 ------
 libc/src/__support/math/CMakeLists.txt          |  2 +-
 libc/src/__support/math/truncf128.h             | 11 ++++-------
 libc/src/math/generic/CMakeLists.txt            |  1 +
 libc/src/math/generic/truncf128.cpp             |  5 ++++-
 libc/src/math/truncf128.h                       |  5 +++++
 libc/test/shared/shared_math_constexpr_test.cpp |  4 ++--
 libc/test/shared/shared_math_test.cpp           |  2 +-
 libc/test/src/math/smoke/CMakeLists.txt         |  1 +
 libc/test/src/math/smoke/truncf128_test.cpp     |  6 +++++-
 23 files changed, 37 insertions(+), 27 deletions(-)

diff --git a/libc/config/baremetal/aarch64/entrypoints.txt b/libc/config/baremetal/aarch64/entrypoints.txt
index a5f804013ffed..982e66c136598 100644
--- a/libc/config/baremetal/aarch64/entrypoints.txt
+++ b/libc/config/baremetal/aarch64/entrypoints.txt
@@ -593,6 +593,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.totalordermagl
     libc.src.math.trunc
     libc.src.math.truncf
+    libc.src.math.truncf128
     libc.src.math.truncl
     libc.src.math.ufromfp
     libc.src.math.ufromfpf
@@ -793,7 +794,6 @@ if(LIBC_TYPES_HAS_NATIVE_FLOAT128)
     libc.src.math.setpayloadsigf128
     libc.src.math.totalorderf128
     libc.src.math.totalordermagf128
-    libc.src.math.truncf128
     libc.src.math.ufromfpf128
     libc.src.math.ufromfpxf128
   )
diff --git a/libc/config/baremetal/arm/entrypoints.txt b/libc/config/baremetal/arm/entrypoints.txt
index baf30685ee1b5..2274654b15c93 100644
--- a/libc/config/baremetal/arm/entrypoints.txt
+++ b/libc/config/baremetal/arm/entrypoints.txt
@@ -605,6 +605,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.totalordermagl
     libc.src.math.trunc
     libc.src.math.truncf
+    libc.src.math.truncf128
     libc.src.math.truncl
     libc.src.math.ufromfp
     libc.src.math.ufromfpf
@@ -804,7 +805,6 @@ if(LIBC_TYPES_HAS_NATIVE_FLOAT128)
     libc.src.math.setpayloadsigf128
     libc.src.math.totalorderf128
     libc.src.math.totalordermagf128
-    libc.src.math.truncf128
     libc.src.math.ufromfpf128
     libc.src.math.ufromfpxf128
   )
diff --git a/libc/config/baremetal/riscv/entrypoints.txt b/libc/config/baremetal/riscv/entrypoints.txt
index d23ea962c4dca..3f4ebe87c9062 100644
--- a/libc/config/baremetal/riscv/entrypoints.txt
+++ b/libc/config/baremetal/riscv/entrypoints.txt
@@ -601,6 +601,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.totalordermagl
     libc.src.math.trunc
     libc.src.math.truncf
+    libc.src.math.truncf128
     libc.src.math.truncl
     libc.src.math.ufromfp
     libc.src.math.ufromfpf
@@ -801,7 +802,6 @@ if(LIBC_TYPES_HAS_NATIVE_FLOAT128)
     libc.src.math.setpayloadsigf128
     libc.src.math.totalorderf128
     libc.src.math.totalordermagf128
-    libc.src.math.truncf128
     libc.src.math.ufromfpf128
     libc.src.math.ufromfpxf128
   )
diff --git a/libc/config/darwin/aarch64/entrypoints.txt b/libc/config/darwin/aarch64/entrypoints.txt
index dc4ed39032445..4ff3aaf377486 100644
--- a/libc/config/darwin/aarch64/entrypoints.txt
+++ b/libc/config/darwin/aarch64/entrypoints.txt
@@ -413,6 +413,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.totalordermagl
     libc.src.math.trunc
     libc.src.math.truncf
+    libc.src.math.truncf128
     libc.src.math.truncl
     libc.src.math.ufromfp
     libc.src.math.ufromfpf
@@ -613,7 +614,6 @@ if(LIBC_TYPES_HAS_NATIVE_FLOAT128)
     libc.src.math.setpayloadsigf128
     libc.src.math.totalorderf128
     libc.src.math.totalordermagf128
-    libc.src.math.truncf128
     libc.src.math.ufromfpf128
     libc.src.math.ufromfpxf128
   )
diff --git a/libc/config/darwin/x86_64/entrypoints.txt b/libc/config/darwin/x86_64/entrypoints.txt
index f3487afaca485..b616ba0d6e002 100644
--- a/libc/config/darwin/x86_64/entrypoints.txt
+++ b/libc/config/darwin/x86_64/entrypoints.txt
@@ -244,6 +244,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     #libc.src.math.totalordermagl
     #libc.src.math.trunc
     #libc.src.math.truncf
+    #libc.src.math.truncf128
     #libc.src.math.truncl
 )
 
diff --git a/libc/config/freebsd/x86_64/entrypoints.txt b/libc/config/freebsd/x86_64/entrypoints.txt
index 2b264ebb8b517..3ae2a2e467c9d 100644
--- a/libc/config/freebsd/x86_64/entrypoints.txt
+++ b/libc/config/freebsd/x86_64/entrypoints.txt
@@ -300,6 +300,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.tanhf
     libc.src.math.trunc
     libc.src.math.truncf
+    libc.src.math.truncf128
     libc.src.math.truncl
 )
 
@@ -551,7 +552,6 @@ if(LIBC_TYPES_HAS_NATIVE_FLOAT128)
     libc.src.math.setpayloadsigf128
     libc.src.math.totalorderf128
     libc.src.math.totalordermagf128
-    libc.src.math.truncf128
     libc.src.math.ufromfpf128
     libc.src.math.ufromfpxf128
   )
diff --git a/libc/config/gpu/amdgpu/entrypoints.txt b/libc/config/gpu/amdgpu/entrypoints.txt
index 772c6a6db38c3..792dd363544af 100644
--- a/libc/config/gpu/amdgpu/entrypoints.txt
+++ b/libc/config/gpu/amdgpu/entrypoints.txt
@@ -539,6 +539,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.totalordermagl
     libc.src.math.trunc
     libc.src.math.truncf
+    libc.src.math.truncf128
     libc.src.math.truncl
     libc.src.math.ufromfp
     libc.src.math.ufromfpf
diff --git a/libc/config/gpu/nvptx/entrypoints.txt b/libc/config/gpu/nvptx/entrypoints.txt
index 4bb6c93fc776c..c12292d43c5d8 100644
--- a/libc/config/gpu/nvptx/entrypoints.txt
+++ b/libc/config/gpu/nvptx/entrypoints.txt
@@ -536,6 +536,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.totalordermagl
     libc.src.math.trunc
     libc.src.math.truncf
+    libc.src.math.truncf128
     libc.src.math.truncl
     # FIXME: Broken.
     # libc.src.math.ufromfp
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index ffe267fca19c7..7a5e8930636be 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -754,6 +754,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.totalordermagl
     libc.src.math.trunc
     libc.src.math.truncf
+    libc.src.math.truncf128
     libc.src.math.truncl
     libc.src.math.ufromfp
     libc.src.math.ufromfpf
@@ -947,7 +948,6 @@ if(LIBC_TYPES_HAS_NATIVE_FLOAT128)
     libc.src.math.setpayloadsigf128
     libc.src.math.totalorderf128
     libc.src.math.totalordermagf128
-    libc.src.math.truncf128
     libc.src.math.ufromfpf128
     libc.src.math.ufromfpxf128
   )
diff --git a/libc/config/linux/arm/entrypoints.txt b/libc/config/linux/arm/entrypoints.txt
index af2a14eb72414..652187d1ba4e3 100644
--- a/libc/config/linux/arm/entrypoints.txt
+++ b/libc/config/linux/arm/entrypoints.txt
@@ -564,6 +564,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.totalordermagl
     libc.src.math.trunc
     libc.src.math.truncf
+    libc.src.math.truncf128
     libc.src.math.truncl
     libc.src.math.ufromfp
     libc.src.math.ufromfpf
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index edda59601796a..71fcd346599ef 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -822,6 +822,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.totalordermagl
     libc.src.math.trunc
     libc.src.math.truncf
+    libc.src.math.truncf128
     libc.src.math.truncl
     libc.src.math.ufromfp
     libc.src.math.ufromfpf
@@ -1032,7 +1033,6 @@ if(LIBC_TYPES_HAS_NATIVE_FLOAT128)
     libc.src.math.setpayloadsigf128
     libc.src.math.totalorderf128
     libc.src.math.totalordermagf128
-    libc.src.math.truncf128
     libc.src.math.ufromfpf128
     libc.src.math.ufromfpxf128
   )
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index cd7bb5d5e8b83..445220c40e19d 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -832,6 +832,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.totalordermagl
     libc.src.math.trunc
     libc.src.math.truncf
+    libc.src.math.truncf128
     libc.src.math.truncl
     libc.src.math.ufromfp
     libc.src.math.ufromfpf
@@ -1042,7 +1043,6 @@ if(LIBC_TYPES_HAS_NATIVE_FLOAT128)
     libc.src.math.setpayloadsigf128
     libc.src.math.totalorderf128
     libc.src.math.totalordermagf128
-    libc.src.math.truncf128
     libc.src.math.ufromfpf128
     libc.src.math.ufromfpxf128
   )
diff --git a/libc/config/windows/entrypoints.txt b/libc/config/windows/entrypoints.txt
index d5e5b61c15e4f..7c46f2b42c3d5 100644
--- a/libc/config/windows/entrypoints.txt
+++ b/libc/config/windows/entrypoints.txt
@@ -334,6 +334,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.tanpif
     libc.src.math.trunc
     libc.src.math.truncf
+    libc.src.math.truncf128
     libc.src.math.truncl
 )
 
diff --git a/libc/shared/math/truncf128.h b/libc/shared/math/truncf128.h
index 0233775d6c6b8..e9de5418e0b30 100644
--- a/libc/shared/math/truncf128.h
+++ b/libc/shared/math/truncf128.h
@@ -9,10 +9,6 @@
 #ifndef LLVM_LIBC_SHARED_MATH_TRUNCF128_H
 #define LLVM_LIBC_SHARED_MATH_TRUNCF128_H
 
-#include "include/llvm-libc-types/float128.h"
-
-#ifdef LIBC_TYPES_HAS_NATIVE_FLOAT128
-
 #include "shared/libc_common.h"
 #include "src/__support/math/truncf128.h"
 
@@ -24,6 +20,4 @@ using math::truncf128;
 } // namespace shared
 } // namespace LIBC_NAMESPACE_DECL
 
-#endif // LIBC_TYPES_HAS_NATIVE_FLOAT128
-
 #endif // LLVM_LIBC_SHARED_MATH_TRUNCF128_H
diff --git a/libc/src/__support/math/CMakeLists.txt b/libc/src/__support/math/CMakeLists.txt
index c0f98d9063ede..3a3a78313a2d0 100644
--- a/libc/src/__support/math/CMakeLists.txt
+++ b/libc/src/__support/math/CMakeLists.txt
@@ -5704,7 +5704,7 @@ add_header_library(
   HDRS
     truncf128.h
   DEPENDS
-    libc.include.llvm-libc-types.float128
+    libc.src.__support.FPUtil.float128
     libc.src.__support.FPUtil.nearest_integer_operations
     libc.src.__support.macros.config
 )
diff --git a/libc/src/__support/math/truncf128.h b/libc/src/__support/math/truncf128.h
index 454b8c1dc2ad5..72e3a100a0935 100644
--- a/libc/src/__support/math/truncf128.h
+++ b/libc/src/__support/math/truncf128.h
@@ -9,23 +9,20 @@
 #ifndef LLVM_LIBC_SRC___SUPPORT_MATH_TRUNCF128_H
 #define LLVM_LIBC_SRC___SUPPORT_MATH_TRUNCF128_H
 
-#include "include/llvm-libc-types/float128.h"
-
-#ifdef LIBC_TYPES_HAS_NATIVE_FLOAT128
-
 #include "src/__support/FPUtil/NearestIntegerOperations.h"
+#include "src/__support/FPUtil/float128.h"
 #include "src/__support/macros/config.h"
 
 namespace LIBC_NAMESPACE_DECL {
 namespace math {
 
-LIBC_INLINE constexpr float128 truncf128(float128 x) {
+using LIBC_NAMESPACE::fputil::Float128;
+
+LIBC_INLINE constexpr Float128 truncf128(Float128 x) {
   return fputil::trunc(x);
 }
 
 } // namespace math
 } // namespace LIBC_NAMESPACE_DECL
 
-#endif // LIBC_TYPES_HAS_NATIVE_FLOAT128
-
 #endif // LLVM_LIBC_SRC___SUPPORT_MATH_TRUNCF128_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 46a9fe4fff0f6..3408f25dd8555 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -604,6 +604,7 @@ add_entrypoint_object(
   HDRS
     ../truncf128.h
   DEPENDS
+    libc.src.__support.CPP.bit
     libc.src.__support.math.truncf128
 )
 
diff --git a/libc/src/math/generic/truncf128.cpp b/libc/src/math/generic/truncf128.cpp
index bef079cbbd6a5..083629a6f7a76 100644
--- a/libc/src/math/generic/truncf128.cpp
+++ b/libc/src/math/generic/truncf128.cpp
@@ -7,12 +7,15 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/math/truncf128.h"
+#include "src/__support/CPP/bit.h"
 #include "src/__support/math/truncf128.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
+using LIBC_NAMESPACE::fputil::Float128;
+
 LLVM_LIBC_FUNCTION(float128, truncf128, (float128 x)) {
-  return math::truncf128(x);
+  return cpp::bit_cast<float128>(math::truncf128(cpp::bit_cast<Float128>(x)));
 }
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/math/truncf128.h b/libc/src/math/truncf128.h
index df3899c35e668..265d8cadcdea6 100644
--- a/libc/src/math/truncf128.h
+++ b/libc/src/math/truncf128.h
@@ -9,11 +9,16 @@
 #ifndef LLVM_LIBC_SRC_MATH_TRUNCF128_H
 #define LLVM_LIBC_SRC_MATH_TRUNCF128_H
 
+#include "src/__support/FPUtil/float128.h"
 #include "src/__support/macros/config.h"
 #include "src/__support/macros/properties/types.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
+#ifndef LIBC_TYPES_HAS_NATIVE_FLOAT128
+using float128 = LIBC_NAMESPACE::fputil::Float128;
+#endif // LIBC_TYPES_HAS_NATIVE_FLOAT128
+
 float128 truncf128(float128 x);
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/shared/shared_math_constexpr_test.cpp b/libc/test/shared/shared_math_constexpr_test.cpp
index 2889a2dd86227..80e8845859c8d 100644
--- a/libc/test/shared/shared_math_constexpr_test.cpp
+++ b/libc/test/shared/shared_math_constexpr_test.cpp
@@ -398,6 +398,8 @@ static_assert(Float128(0.0) ==
               LIBC_NAMESPACE::shared::roundevenf128(Float128(0.0)));
 static_assert(Float128(0.0) ==
               LIBC_NAMESPACE::shared::roundf128(Float128(0.0)));
+static_assert(Float128(0.0) ==
+              LIBC_NAMESPACE::shared::truncf128(Float128(0.0)));
 
 //===----------------------------------------------------------------------===//
 //                       Native Float128 Tests
@@ -509,8 +511,6 @@ static_assert(1 == [] {
              LIBC_NAMESPACE::shared::nanf128(&arg))
       .is_nan();
 }());
-static_assert(float128(0.0) ==
-              LIBC_NAMESPACE::shared::truncf128(float128(0.0)));
 
 #endif // LIBC_TYPES_HAS_NATIVE_FLOAT128
 
diff --git a/libc/test/shared/shared_math_test.cpp b/libc/test/shared/shared_math_test.cpp
index d964a178fa855..bfca2578ddda2 100644
--- a/libc/test/shared/shared_math_test.cpp
+++ b/libc/test/shared/shared_math_test.cpp
@@ -600,6 +600,7 @@ TEST(LlvmLibcSharedMathTest, AllEmuFloat128) {
                LIBC_NAMESPACE::shared::roundevenf128(Float128(0.0)));
   EXPECT_FP_EQ(Float128(0.0), LIBC_NAMESPACE::shared::roundf128(Float128(0.0)));
   EXPECT_FP_EQ(Float128(1.0), LIBC_NAMESPACE::shared::sqrtf128(Float128(1.0)));
+  EXPECT_FP_EQ(Float128(0.0), LIBC_NAMESPACE::shared::truncf128(Float128(0.0)));
 }
 
 #ifdef LIBC_TYPES_HAS_NATIVE_FLOAT128
@@ -755,7 +756,6 @@ TEST(LlvmLibcSharedMathTest, AllFloat128) {
   EXPECT_EQ(0, LIBC_NAMESPACE::shared::isnanf128(float128(0.0)));
   EXPECT_EQ(0, LIBC_NAMESPACE::shared::issignalingf128(float128(0.0)));
   EXPECT_TRUE(FPBits(LIBC_NAMESPACE::shared::nanf128("")).is_nan());
-  EXPECT_FP_EQ(float128(0.0), LIBC_NAMESPACE::shared::truncf128(float128(0.0)));
 }
 
 #endif // LIBC_TYPES_HAS_NATIVE_FLOAT128
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index 7af2eb21d24d0..9a43e2271ec38 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -363,6 +363,7 @@ add_fp_unittest(
     TruncTest.h
   DEPENDS
     libc.src.math.truncf128
+    libc.src.__support.FPUtil.float128
     libc.src.__support.FPUtil.fp_bits
 )
 
diff --git a/libc/test/src/math/smoke/truncf128_test.cpp b/libc/test/src/math/smoke/truncf128_test.cpp
index 7d6487b7d8567..f486213110b6b 100644
--- a/libc/test/src/math/smoke/truncf128_test.cpp
+++ b/libc/test/src/math/smoke/truncf128_test.cpp
@@ -7,7 +7,11 @@
 //===----------------------------------------------------------------------===//
 
 #include "TruncTest.h"
-
+#include "src/__support/FPUtil/float128.h"
 #include "src/math/truncf128.h"
 
+#ifndef LIBC_TYPES_HAS_NATIVE_FLOAT128
+using float128 = LIBC_NAMESPACE::fputil::Float128;
+#endif // LIBC_TYPES_HAS_NATIVE_FLOAT128
+
 LIST_TRUNC_TESTS(float128, LIBC_NAMESPACE::truncf128)

>From f9512403f575ebe53a7908a9b8deb4cc06e73c65 Mon Sep 17 00:00:00 2001
From: Sukumarsawant <sawantsukumar at gmail.com>
Date: Tue, 18 Aug 2026 17:29:30 +0530
Subject: [PATCH 2/3] mpfr tests

---
 libc/test/src/math/CMakeLists.txt     | 16 ++++++++++++++++
 libc/test/src/math/truncf128_test.cpp | 18 ++++++++++++++++++
 2 files changed, 34 insertions(+)
 create mode 100644 libc/test/src/math/truncf128_test.cpp

diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index 7d20cedc0f7bf..90c29922d5a35 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -392,6 +392,22 @@ add_fp_unittest(
     libc.src.__support.FPUtil.fp_bits
 )
 
+add_fp_unittest(
+  truncf128_test
+  NEED_MPFR_F128
+  SUITE
+    libc-math-unittests
+  SRCS
+    truncf128_test.cpp
+  HDRS
+    TruncTest.h
+  DEPENDS
+    libc.src.math.truncf128
+    libc.src.__support.CPP.algorithm
+    libc.src.__support.FPUtil.float128
+    libc.src.__support.FPUtil.fp_bits
+)
+
 add_fp_unittest(
   truncf16_test
   NEED_MPFR
diff --git a/libc/test/src/math/truncf128_test.cpp b/libc/test/src/math/truncf128_test.cpp
new file mode 100644
index 0000000000000..05af1a73b117b
--- /dev/null
+++ b/libc/test/src/math/truncf128_test.cpp
@@ -0,0 +1,18 @@
+//===-- Unittests for truncf128 -------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "TruncTest.h"
+
+#include "src/math/floorf128.h"
+#include "src/math/truncf128.h"
+
+#ifndef LIBC_TYPES_HAS_NATIVE_FLOAT128
+using float128 = LIBC_NAMESPACE::fputil::Float128;
+#endif // LIBC_TYPES_HAS_NATIVE_FLOAT128
+
+LIST_TRUNC_TESTS(float128, LIBC_NAMESPACE::truncf128)

>From 0267817566df4034027b45afe45ccb578ee6f616 Mon Sep 17 00:00:00 2001
From: Sukumarsawant <sawantsukumar at gmail.com>
Date: Wed, 19 Aug 2026 14:55:51 +0530
Subject: [PATCH 3/3] nits + bazel

---
 libc/test/src/math/truncf128_test.cpp                         | 2 +-
 utils/bazel/llvm-project-overlay/libc/BUILD.bazel             | 4 +++-
 .../llvm-project-overlay/libc/test/src/math/smoke/BUILD.bazel | 3 +++
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/libc/test/src/math/truncf128_test.cpp b/libc/test/src/math/truncf128_test.cpp
index 05af1a73b117b..592a6b7cd55e7 100644
--- a/libc/test/src/math/truncf128_test.cpp
+++ b/libc/test/src/math/truncf128_test.cpp
@@ -8,7 +8,7 @@
 
 #include "TruncTest.h"
 
-#include "src/math/floorf128.h"
+#include "src/__support/FPUtil/float128.h"
 #include "src/math/truncf128.h"
 
 #ifndef LIBC_TYPES_HAS_NATIVE_FLOAT128
diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
index ebfdc6252e59c..e76ee60d70d4e 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -10042,9 +10042,9 @@ libc_support_library(
     name = "__support_math_truncf128",
     hdrs = ["src/__support/math/truncf128.h"],
     deps = [
+        ":__support_fputil_float128",
         ":__support_fputil_nearest_integer_operations",
         ":__support_macros_config",
-        ":llvm_libc_types_float128",
     ],
 )
 
@@ -13771,6 +13771,8 @@ libc_math_function(
 libc_math_function(
     name = "truncf128",
     additional_deps = [
+        ":__support_cpp_bit",
+        ":__support_fputil_float128",
         ":__support_math_truncf128",
     ],
 )
diff --git a/utils/bazel/llvm-project-overlay/libc/test/src/math/smoke/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/test/src/math/smoke/BUILD.bazel
index 414290fd0979e..cf75a206a0598 100644
--- a/utils/bazel/llvm-project-overlay/libc/test/src/math/smoke/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/test/src/math/smoke/BUILD.bazel
@@ -1674,6 +1674,9 @@ math_test(
 math_test(
     name = "truncf128",
     hdrs = ["TruncTest.h"],
+    deps = [
+        "//libc:__support_fputil_float128",
+    ],
 )
 
 math_test(



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