diff --git a/docs/ReleaseNotes.md b/docs/ReleaseNotes.md
index 02b1755bf8..71aa35dc94 100644
--- a/docs/ReleaseNotes.md
+++ b/docs/ReleaseNotes.md
@@ -86,6 +86,8 @@ line upon naming the release. Refer to previous for appropriate section names.
 - Fixed members following a merged bitfield reading the wrong value when a
   struct is flat-converted
   [#8526](https://github.com/microsoft/DirectXShaderCompiler/issues/8526).
+- Fixed a C++26 compilation error in `llvm::sys::TimeValue` due to arithmetic on unscoped enumeration `NANOSECONDS_PER_SECOND`
+  [#8992](https://github.com/microsoft/DirectXShaderCompiler/issues/8992).
 
 ### Upcoming Preview Release
 
diff --git a/include/llvm/Support/TimeValue.h b/include/llvm/Support/TimeValue.h
index 6bca58b6bc..1e23644cd5 100644
--- a/include/llvm/Support/TimeValue.h
+++ b/include/llvm/Support/TimeValue.h
@@ -107,8 +107,9 @@ namespace sys {
       : seconds_( 0 ) , nanos_ ( 0 ) {
       SecondsType integer_part = static_cast<SecondsType>( new_time );
       seconds_ = integer_part;
-      nanos_ = static_cast<NanoSecondsType>( (new_time -
-               static_cast<double>(integer_part)) * NANOSECONDS_PER_SECOND );
+      nanos_ = static_cast<NanoSecondsType>(
+          (new_time - static_cast<double>(integer_part)) *
+          static_cast<double>(NANOSECONDS_PER_SECOND));
       this->normalize();
     }
 
diff --git a/unittests/Support/TimeValueTest.cpp b/unittests/Support/TimeValueTest.cpp
index 3d2b9780c0..c10bbba114 100644
--- a/unittests/Support/TimeValueTest.cpp
+++ b/unittests/Support/TimeValueTest.cpp
@@ -37,4 +37,9 @@ TEST(TimeValue, Win32FILETIME) {
   EXPECT_EQ(ft1970, epoch.toWin32Time());
 }
 
+TEST(TimeValue, DoubleConstructor) {
+  sys::TimeValue tv(1234.5);
+  EXPECT_EQ(1234, tv.seconds());
+  EXPECT_EQ(500000000u, static_cast<uint32_t>(tv.nanoseconds()));
+}
 }