diff --git a/include/llvm/IR/Metadata.h b/include/llvm/IR/Metadata.h
index a514b6006d5..df8ce354bb7 100644
--- a/include/llvm/IR/Metadata.h
+++ b/include/llvm/IR/Metadata.h
@@ -592,11 +592,9 @@ class MDString : public Metadata {
 
   StringMapEntry<MDString> *Entry;
   MDString() : Metadata(MDStringKind, Uniqued), Entry(nullptr) {}
+  MDString(MDString &&) : Metadata(MDStringKind, Uniqued) {}
 
 public:
-  // This is a "default" move ctor, MSVC does not support "= default" here
-  MDString(MDString &&R)
-      : Metadata(MDStringKind, Uniqued), Entry(std::move(R.Entry)) {}
   static MDString *get(LLVMContext &Context, StringRef Str);
   static MDString *get(LLVMContext &Context, const char *Str) {
     return get(Context, Str ? StringRef(Str) : StringRef());
diff --git a/lib/IR/Metadata.cpp b/lib/IR/Metadata.cpp
index ddb9cc4e17f..cc0c568c861 100644
--- a/lib/IR/Metadata.cpp
+++ b/lib/IR/Metadata.cpp
@@ -397,12 +397,17 @@ void ValueAsMetadata::handleRAUW(Value *From, Value *To) {
 
 MDString *MDString::get(LLVMContext &Context, StringRef Str) {
   auto &Store = Context.pImpl->MDStringCache;
-  auto I = Store.insert(std::make_pair(Str, MDString()));
-  auto &MapEntry = I.first->getValue();
-  if (!I.second)
-    return &MapEntry;
-  MapEntry.Entry = &*I.first;
-  return &MapEntry;
+  auto I = Store.find(Str);
+  if (I != Store.end())
+    return &I->second;
+
+  auto *Entry =
+      StringMapEntry<MDString>::Create(Str, Store.getAllocator(), MDString());
+  bool WasInserted = Store.insert(Entry);
+  (void)WasInserted;
+  assert(WasInserted && "Expected entry to be inserted");
+  Entry->second.Entry = Entry;
+  return &Entry->second;
 }
 
 StringRef MDString::getString() const {