diff --git a/llvm/include/llvm/CodeGen/RegisterPressure.h b/llvm/include/llvm/CodeGen/RegisterPressure.h
--- a/llvm/include/llvm/CodeGen/RegisterPressure.h
+++ b/llvm/include/llvm/CodeGen/RegisterPressure.h
@@ -201,6 +201,8 @@
 
 public:
   PressureDiffs() = default;
+  PressureDiffs &operator=(const PressureDiffs &other) = delete;
+  PressureDiffs(const PressureDiffs &other) = delete;
   ~PressureDiffs() { free(PDiffArray); }
 
   void clear() { Size = 0; }