[C++] Use 'nullptr'. Transforms edition.

llvm-svn: 207196
diff --git a/llvm/lib/Transforms/IPO/Internalize.cpp b/llvm/lib/Transforms/IPO/Internalize.cpp
index 2ca0bdb..cdb85fd 100644
--- a/llvm/lib/Transforms/IPO/Internalize.cpp
+++ b/llvm/lib/Transforms/IPO/Internalize.cpp
@@ -132,8 +132,8 @@
 
 bool InternalizePass::runOnModule(Module &M) {
   CallGraphWrapperPass *CGPass = getAnalysisIfAvailable<CallGraphWrapperPass>();
-  CallGraph *CG = CGPass ? &CGPass->getCallGraph() : 0;
-  CallGraphNode *ExternalNode = CG ? CG->getExternalCallingNode() : 0;
+  CallGraph *CG = CGPass ? &CGPass->getCallGraph() : nullptr;
+  CallGraphNode *ExternalNode = CG ? CG->getExternalCallingNode() : nullptr;
   bool Changed = false;
 
   SmallPtrSet<GlobalValue *, 8> Used;