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

llvm-svn: 207196
diff --git a/llvm/lib/Transforms/ObjCARC/DependencyAnalysis.cpp b/llvm/lib/Transforms/ObjCARC/DependencyAnalysis.cpp
index db8e4c3..08c8842 100644
--- a/llvm/lib/Transforms/ObjCARC/DependencyAnalysis.cpp
+++ b/llvm/lib/Transforms/ObjCARC/DependencyAnalysis.cpp
@@ -224,7 +224,7 @@
         pred_iterator PI(LocalStartBB), PE(LocalStartBB, false);
         if (PI == PE)
           // If we've reached the function entry, produce a null dependence.
-          DependingInsts.insert(0);
+          DependingInsts.insert(nullptr);
         else
           // Add the predecessors to the worklist.
           do {