Index: llvm/trunk/lib/CodeGen/MachineVerifier.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/MachineVerifier.cpp
+++ llvm/trunk/lib/CodeGen/MachineVerifier.cpp
@@ -260,8 +260,8 @@
     static char ID; // Pass ID, replacement for typeid
     const std::string Banner;
 
-    MachineVerifierPass(const std::string &banner = nullptr)
-      : MachineFunctionPass(ID), Banner(banner) {
+    MachineVerifierPass(const std::string banner = std::string())
+      : MachineFunctionPass(ID), Banner(std::move(banner)) {
         initializeMachineVerifierPassPass(*PassRegistry::getPassRegistry());
       }