Move DeadControl into the JSGraph so that it can be reused.

src/compiler/control-reducer.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/common-operator.h"
 #include "src/compiler/control-reducer.h"
 #include "src/compiler/graph.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-marker.h"
 #include "src/compiler/node-matchers.h"
@@ skipping 36 matching lines @@
 
 class ControlReducerImpl {
  public:
   ControlReducerImpl(Zone* zone, JSGraph* jsgraph,
                      CommonOperatorBuilder* common)
       : zone_(zone),
         jsgraph_(jsgraph),
         common_(common),
         state_(jsgraph->graph()->NodeCount(), kUnvisited, zone_),
         stack_(zone_),
-        revisit_(zone_),
-        dead_(NULL) {}
+        revisit_(zone_) {}
 
   Zone* zone_;
   JSGraph* jsgraph_;
   CommonOperatorBuilder* common_;
   ZoneVector<VisitState> state_;
   ZoneDeque<Node*> stack_;
   ZoneDeque<Node*> revisit_;
-  Node* dead_;
 
   void Reduce() {
     Push(graph()->end());
     do {
       // Process the node on the top of the stack, potentially pushing more
       // or popping the node off the stack.
       ReduceTop();
       // If the stack becomes empty, revisit any nodes in the revisit queue.
       // If no nodes in the revisit queue, try removing dead loops.
       // If no dead loops, then finish.
@@ skipping 296 matching lines @@
     }
   }
 
   // Mark {node} as visited.
   void MarkAsVisited(Node* node) {
     size_t id = static_cast<size_t>(node->id());
     EnsureStateSize(id);
     state_[id] = kVisited;
   }
 
-  Node* dead() {
-    if (dead_ == NULL) dead_ = graph()->NewNode(common_->Dead());
-    return dead_;
-  }
+  Node* dead() { return jsgraph_->DeadControl(); }
 
   //===========================================================================
   // Reducer implementation: perform reductions on a node.
   //===========================================================================
   Node* ReduceNode(Node* node) {
     if (node->op()->ControlInputCount() == 1) {
       // If a node has only one control input and it is dead, replace with dead.
       Node* control = NodeProperties::GetControlInput(node);
       if (control->opcode() == IrOpcode::kDead) {
         TRACE(("ControlDead: #%d:%s\n", node->id(), node->op()->mnemonic()));
@@ skipping 247 matching lines @@
       return impl.ReduceIfTrue(node);
     case IrOpcode::kIfFalse:
       return impl.ReduceIfFalse(node);
     default:
       return node;
   }
 }
 }
 }
 }  // namespace v8::internal::compiler