[turbofan] Tiny cleanup in RawMachineAssembler constructor.

src/compiler/raw-machine-assembler.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/raw-machine-assembler.h"
 
 #include "src/code-factory.h"
 #include "src/compiler/pipeline.h"
 #include "src/compiler/scheduler.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 RawMachineAssembler::RawMachineAssembler(Isolate* isolate, Graph* graph,
                                          CallDescriptor* call_descriptor,
                                          MachineType word,
                                          MachineOperatorBuilder::Flags flags)
     : isolate_(isolate),
       graph_(graph),
       schedule_(new (zone()) Schedule(zone())),
       machine_(zone(), word, flags),
       common_(zone()),
       call_descriptor_(call_descriptor),
-      parameters_(nullptr),
+      parameters_(parameter_count(), zone()),
       current_block_(schedule()->start()) {
   int param_count = static_cast<int>(parameter_count());
-  // Add an extra input node for the JSFunction parameter to the start node.
-  Node* s = graph->NewNode(common_.Start(param_count + 1));
-  graph->SetStart(s);
-  if (parameter_count() == 0) return;
-  parameters_ = zone()->NewArray<Node*>(param_count);
+  // Add an extra input for the JSFunction parameter to the start node.
+  graph->SetStart(graph->NewNode(common_.Start(param_count + 1)));
   for (size_t i = 0; i < parameter_count(); ++i) {
     parameters_[i] =
         AddNode(common()->Parameter(static_cast<int>(i)), graph->start());
   }
 }
 
 
 Schedule* RawMachineAssembler::Export() {
   // Compute the correct codegen order.
   DCHECK(schedule_->rpo_order()->empty());
@@ skipping 291 matching lines @@
 Node* RawMachineAssembler::MakeNode(const Operator* op, int input_count,
                                     Node** inputs) {
   // The raw machine assembler nodes do not have effect and control inputs,
   // so we disable checking input counts here.
   return graph()->NewNodeUnchecked(op, input_count, inputs);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8