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

src/compiler/arm64/instruction-selector-arm64.cc

 // Copyright 2014 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/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 1814 matching lines @@
         return VisitFloat64Compare(this, value, &cont);
       case IrOpcode::kFloat64LessThanOrEqual:
         cont.OverwriteAndNegateIfEqual(kFloatLessThanOrEqual);
         return VisitFloat64Compare(this, value, &cont);
       case IrOpcode::kProjection:
         // Check if this is the overflow output projection of an
         // <Operation>WithOverflow node.
         if (ProjectionIndexOf(value->op()) == 1u) {
           // We cannot combine the <Operation>WithOverflow with this branch
           // unless the 0th projection (the use of the actual value of the
-          // <Operation> is either NULL, which means there's no use of the
+          // <Operation> is either nullptr, which means there's no use of the
           // actual value, or was already defined, which means it is scheduled
           // *AFTER* this branch).
           Node* const node = value->InputAt(0);
           Node* const result = NodeProperties::FindProjection(node, 0);
-          if (result == NULL || IsDefined(result)) {
+          if (result == nullptr || IsDefined(result)) {
             switch (node->opcode()) {
               case IrOpcode::kInt32AddWithOverflow:
                 cont.OverwriteAndNegateIfEqual(kOverflow);
                 return VisitBinop<Int32BinopMatcher>(this, node, kArm64Add32,
                                                      kArithmeticImm, &cont);
               case IrOpcode::kInt32SubWithOverflow:
                 cont.OverwriteAndNegateIfEqual(kOverflow);
                 return VisitBinop<Int32BinopMatcher>(this, node, kArm64Sub32,
                                                      kArithmeticImm, &cont);
               case IrOpcode::kInt64AddWithOverflow:
@@ skipping 339 matching lines @@
          MachineOperatorBuilder::kFloat32RoundTiesEven |
          MachineOperatorBuilder::kFloat64RoundTiesEven |
          MachineOperatorBuilder::kWord32ShiftIsSafe |
          MachineOperatorBuilder::kInt32DivIsSafe |
          MachineOperatorBuilder::kUint32DivIsSafe;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8