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

llvm-svn: 207196
diff --git a/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp b/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
index 4a3a0cd..d0a4266 100644
--- a/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
+++ b/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
@@ -765,7 +765,7 @@
 
   // Find out the new return value.
   Type *RetTy = FTy->getReturnType();
-  Type *NRetTy = NULL;
+  Type *NRetTy = nullptr;
   unsigned RetCount = NumRetVals(F);
 
   // -1 means unused, other numbers are the new index
@@ -1051,7 +1051,7 @@
         Value *RetVal;
 
         if (NFTy->getReturnType()->isVoidTy()) {
-          RetVal = 0;
+          RetVal = nullptr;
         } else {
           assert (RetTy->isStructTy());
           // The original return value was a struct, insert