[C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr.

llvm-svn: 206142
diff --git a/llvm/lib/CodeGen/MachineFunctionAnalysis.cpp b/llvm/lib/CodeGen/MachineFunctionAnalysis.cpp
index 35591e1..46cd60a 100644
--- a/llvm/lib/CodeGen/MachineFunctionAnalysis.cpp
+++ b/llvm/lib/CodeGen/MachineFunctionAnalysis.cpp
@@ -20,7 +20,7 @@
 char MachineFunctionAnalysis::ID = 0;
 
 MachineFunctionAnalysis::MachineFunctionAnalysis(const TargetMachine &tm) :
-  FunctionPass(ID), TM(tm), MF(0) {
+  FunctionPass(ID), TM(tm), MF(nullptr) {
   initializeMachineModuleInfoPass(*PassRegistry::getPassRegistry());
 }
 
@@ -53,5 +53,5 @@
 
 void MachineFunctionAnalysis::releaseMemory() {
   delete MF;
-  MF = 0;
+  MF = nullptr;
 }