diff --git a/lib/CodeGen/MachineSSAUpdater.cpp b/lib/CodeGen/MachineSSAUpdater.cpp
index 77496ad..d9173a2 100644
--- a/lib/CodeGen/MachineSSAUpdater.cpp
+++ b/lib/CodeGen/MachineSSAUpdater.cpp
@@ -29,6 +29,8 @@
 #include "llvm/Transforms/Utils/SSAUpdaterImpl.h"
 using namespace llvm;
 
+#define DEBUG_TYPE "machine-ssaupdater"
+
 typedef DenseMap<MachineBasicBlock*, unsigned> AvailableValsTy;
 static AvailableValsTy &getAvailableVals(void *AV) {
   return *static_cast<AvailableValsTy*>(AV);
@@ -36,7 +38,7 @@
 
 MachineSSAUpdater::MachineSSAUpdater(MachineFunction &MF,
                                      SmallVectorImpl<MachineInstr*> *NewPHI)
-  : AV(0), InsertedPHIs(NewPHI) {
+  : AV(nullptr), InsertedPHIs(NewPHI) {
   TII = MF.getTarget().getInstrInfo();
   MRI = &MF.getRegInfo();
 }
@@ -48,7 +50,7 @@
 /// Initialize - Reset this object to get ready for a new set of SSA
 /// updates.  ProtoValue is the value used to name PHI nodes.
 void MachineSSAUpdater::Initialize(unsigned V) {
-  if (AV == 0)
+  if (!AV)
     AV = new AvailableValsTy();
   else
     getAvailableVals(AV).clear();
@@ -313,7 +315,7 @@
   static MachineInstr *InstrIsPHI(MachineInstr *I) {
     if (I && I->isPHI())
       return I;
-    return 0;
+    return nullptr;
   }
 
   /// ValueIsPHI - Check if the instruction that defines the specified register
@@ -328,7 +330,7 @@
     MachineInstr *PHI = ValueIsPHI(Val, Updater);
     if (PHI && PHI->getNumOperands() <= 1)
       return PHI;
-    return 0;
+    return nullptr;
   }
 
   /// GetPHIValue - For the specified PHI instruction, return the register