[turbofan] Build s/NULL/nullptr/g and CHECK(x != nullptr) to CHECK_NOT_NULL(x).

src/compiler/control-equivalence.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/control-equivalence.h"
 #include "src/compiler/node-properties.h"
 
 #define TRACE(...)                                 \
   do {                                             \
     if (FLAG_trace_turbo_ceq) PrintF(__VA_ARGS__); \
@@ skipping 53 matching lines @@
 
 void ControlEquivalence::VisitPost(Node* node, Node* parent_node,
                                    DFSDirection direction) {
   TRACE("CEQ: Post-visit of #%d:%s\n", node->id(), node->op()->mnemonic());
   BracketList& blist = GetBracketList(node);
 
   // Remove brackets pointing to this node [line:19].
   BracketListDelete(blist, node, direction);
 
   // Propagate bracket list up the DFS tree [line:13].
-  if (parent_node != NULL) {
+  if (parent_node != nullptr) {
     BracketList& parent_blist = GetBracketList(parent_node);
     parent_blist.splice(parent_blist.end(), blist);
   }
 }
 
 
 void ControlEquivalence::VisitBackedge(Node* from, Node* to,
                                        DFSDirection direction) {
   TRACE("CEQ: Backedge from #%d:%s to #%d:%s\n", from->id(),
         from->op()->mnemonic(), to->id(), to->op()->mnemonic());
 
   // Push backedge onto the bracket list [line:25].
   Bracket bracket = {direction, kInvalidClass, 0, from, to};
   GetBracketList(from).push_back(bracket);
 }
 
 
 void ControlEquivalence::RunUndirectedDFS(Node* exit) {
   ZoneStack<DFSStackEntry> stack(zone_);
-  DFSPush(stack, exit, NULL, kInputDirection);
+  DFSPush(stack, exit, nullptr, kInputDirection);
   VisitPre(exit);
 
   while (!stack.empty()) {  // Undirected depth-first backwards traversal.
     DFSStackEntry& entry = stack.top();
     Node* node = entry.node;
 
     if (entry.direction == kInputDirection) {
       if (entry.input != node->input_edges().end()) {
         Edge edge = *entry.input;
         Node* input = edge.to();
@@ skipping 123 matching lines @@
     for (Bracket bracket : blist) {
       TRACE("{%d->%d} ", bracket.from->id(), bracket.to->id());
     }
     TRACE("\n");
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8