diff --git a/llvm/lib/Demangle/MicrosoftDemangle.cpp b/llvm/lib/Demangle/MicrosoftDemangle.cpp
index 8b253bf67bcf..f2ad6899735e 100644
--- a/llvm/lib/Demangle/MicrosoftDemangle.cpp
+++ b/llvm/lib/Demangle/MicrosoftDemangle.cpp
@@ -2170,6 +2170,8 @@ Name *Demangler::demangleAnonymousNamespaceName(StringView &MangledName) {
     Error = true;
     return nullptr;
   }
+  StringView NamespaceKey = MangledName.substr(0, EndPos);
+  memorizeString(NamespaceKey);
   MangledName = MangledName.substr(EndPos + 1);
   return Node;
 }
diff --git a/llvm/test/Demangle/ms-back-references.test b/llvm/test/Demangle/ms-back-references.test
index b9ce7c21520b..53bc8b449ed9 100644
--- a/llvm/test/Demangle/ms-back-references.test
+++ b/llvm/test/Demangle/ms-back-references.test
@@ -166,3 +166,6 @@
 
 ??$fun_tmpl_recurse@H$1?ident@fn_space@@YA?AURetVal@2@H@Z@fn_space@@YA?AURetVal@0@H@Z
 ; CHECK: struct fn_space::RetVal __cdecl fn_space::fun_tmpl_recurse<int, &struct fn_space::RetVal __cdecl fn_space::ident(int)>(int)
+
+?AddEmitPasses@EmitAssemblyHelper@?A0x43583946@@AEAA_NAEAVPassManager@legacy@llvm@@W4BackendAction@clang@@AEAVraw_pwrite_stream@5@PEAV85@@Z
+; CHECK: bool __cdecl `anonymous namespace'::EmitAssemblyHelper::AddEmitPasses(class llvm::legacy::PassManager &, enum clang::BackendAction, class llvm::raw_pwrite_stream &, class llvm::raw_pwrite_stream *)