[turbofan] Initial version of branch cloning.

src/compiler/control-flow-optimizer.h

 // 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.
 
 #ifndef V8_COMPILER_CONTROL_FLOW_OPTIMIZER_H_
 #define V8_COMPILER_CONTROL_FLOW_OPTIMIZER_H_
 
 #include "src/compiler/node-marker.h"
 #include "src/zone-containers.h"
 
@@ skipping 13 matching lines @@
  public:
   ControlFlowOptimizer(JSGraph* jsgraph, Zone* zone);
 
   void Optimize();
 
  private:
   void Enqueue(Node* node);
   void VisitNode(Node* node);
   void VisitBranch(Node* node);
 
+  bool TryBuildSwitch(Node* node);
+  bool TryCloneBranch(Node* node);
+
   CommonOperatorBuilder* common() const;
   Graph* graph() const;
   JSGraph* jsgraph() const { return jsgraph_; }
   MachineOperatorBuilder* machine() const;
   Zone* zone() const { return zone_; }
 
   JSGraph* const jsgraph_;
   ZoneQueue<Node*> queue_;
   NodeMarker<bool> queued_;
   Zone* const zone_;
 
   DISALLOW_COPY_AND_ASSIGN(ControlFlowOptimizer);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_CONTROL_FLOW_OPTIMIZER_H_