diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 1ae35e6881d2f8..f0da6ca497b575 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -54,6 +54,12 @@ ABI Changes in This Version
   inline member function that contains a static local variable with a dynamic
   initializer is declared with ``__declspec(dllimport)``. (#GH83616).
 
+- Fixed Microsoft name mangling of lifetime extended temporary objects. This
+  change corrects missing back reference registrations that could result in
+  incorrect back reference indexes and suprising demangled name results. Since
+  MSVC uses a different mangling for these objects, compatibility is not affected.
+  (#GH85423).
+
 AST Dumping Potentially Breaking Changes
 ----------------------------------------
 
diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index aa26bb7ed46f48..cf9c2093a8f6a1 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -3911,7 +3911,8 @@ void MicrosoftMangleContextImpl::mangleReferenceTemporary(
   msvc_hashing_ostream MHO(Out);
   MicrosoftCXXNameMangler Mangler(*this, MHO);
 
-  Mangler.getStream() << "?$RT" << ManglingNumber << '@';
+  Mangler.getStream() << "?";
+  Mangler.mangleSourceName("$RT" + llvm::utostr(ManglingNumber));
   Mangler.mangle(VD, "");
 }
 
diff --git a/clang/test/CodeGenCXX/mangle-ms-back-references.cpp b/clang/test/CodeGenCXX/mangle-ms-back-references.cpp
index b27a9c5acacb77..8707bff9534070 100644
--- a/clang/test/CodeGenCXX/mangle-ms-back-references.cpp
+++ b/clang/test/CodeGenCXX/mangle-ms-back-references.cpp
@@ -1,5 +1,18 @@
 // RUN: %clang_cc1 -fms-extensions -fblocks -emit-llvm %s -o - -triple=i386-pc-win32 | FileCheck %s
 
+namespace NS {
+// The name "RT1" for the name of the class below has been specifically
+// chosen to ensure that back reference lookup does not match against the
+// implicitly generated "$RT1" name of the reference temporary symbol.
+struct RT1 {
+  static const RT1& singleton;
+  int i;
+};
+const RT1& RT1::singleton = RT1{1};
+}
+// CHECK: "?$RT1@singleton@RT1@NS@@2ABU23@B"
+// CHECK: "?singleton@RT1@NS@@2ABU12@B"
+
 void f1(const char* a, const char* b) {}
 // CHECK: "?f1@@YAXPBD0@Z"