Subzero: Convert NULL->nullptr.

src/IceTargetLowering.h

 //===- subzero/src/IceTargetLowering.h - Lowering interface -----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the TargetLowering and LoweringContext
@@ skipping 19 matching lines @@
 // instructions in a node, and insert new (lowered) instructions at
 // the current point.  Along with the instruction list container and
 // associated iterators, it holds the current node, which is needed
 // when inserting new instructions in order to track whether variables
 // are used as single-block or multi-block.
 class LoweringContext {
   LoweringContext(const LoweringContext &) = delete;
   LoweringContext &operator=(const LoweringContext &) = delete;
 
 public:
-  LoweringContext() : Node(NULL), LastInserted(NULL) {}
+  LoweringContext() : Node(nullptr), LastInserted(nullptr) {}
   ~LoweringContext() {}
   void init(CfgNode *Node);
   Inst *getNextInst() const {
     if (Next == End)
-      return NULL;
+      return nullptr;
     return Next;
   }
   Inst *getNextInst(InstList::iterator &Iter) const {
     advanceForward(Iter);
     if (Iter == End)
-      return NULL;
+      return nullptr;
     return Iter;
   }
   CfgNode *getNode() const { return Node; }
   bool atEnd() const { return Cur == End; }
   InstList::iterator getCur() const { return Cur; }
   InstList::iterator getNext() const { return Next; }
   InstList::iterator getEnd() const { return End; }
   void insert(Inst *Inst);
   Inst *getLastInserted() const;
   void advanceCur() { Cur = Next; }
@@ skipping 200 matching lines @@
   virtual void lower(const VariableDeclaration &Var) = 0;
 
 protected:
   TargetGlobalInitLowering(GlobalContext *Ctx) : Ctx(Ctx) {}
   GlobalContext *Ctx;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERING_H