diff --git a/llvm/include/llvm/ADT/IntervalMap.h b/llvm/include/llvm/ADT/IntervalMap.h
--- a/llvm/include/llvm/ADT/IntervalMap.h
+++ b/llvm/include/llvm/ADT/IntervalMap.h
@@ -1042,6 +1042,13 @@
     new(&rootLeaf()) RootLeaf();
   }
 
+  // Delete copy/move constructors and assignment operators because the
+  // default ones may not do the right thing (e.g. deep vs. shallow copy).
+  IntervalMap(const IntervalMap &Other) = delete;
+  IntervalMap(IntervalMap &&Other) = delete;
+  IntervalMap &operator=(const IntervalMap &Other) = delete;
+  IntervalMap &operator=(IntervalMap &&Other) = delete;
+
   ~IntervalMap() {
     clear();
     rootLeaf().~RootLeaf();