Refactor branch instructions to enable further optimizations.

runtime/vm/flow_graph_optimizer.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_FLOW_GRAPH_OPTIMIZER_H_
 #define VM_FLOW_GRAPH_OPTIMIZER_H_
 
 #include "vm/intermediate_language.h"
 #include "vm/flow_graph.h"
 
@@ skipping 12 matching lines @@
   void ApplyICData();
 
   void OptimizeComputations();
 
   virtual void VisitStaticCall(StaticCallComp* comp, BindInstr* instr);
   virtual void VisitInstanceCall(InstanceCallComp* comp, BindInstr* instr);
   virtual void VisitRelationalOp(RelationalOpComp* comp, BindInstr* instr);
   virtual void VisitEqualityCompare(EqualityCompareComp* comp,
                                     BindInstr* instr);
   virtual void VisitBind(BindInstr* instr);
+  virtual void VisitBranch(BranchInstr* instr);
 
  private:
   bool TryReplaceWithArrayOp(BindInstr* instr,
                              InstanceCallComp* comp,
                              Token::Kind op_kind);
   bool TryReplaceWithBinaryOp(BindInstr* instr,
                               InstanceCallComp* comp,
                               Token::Kind op_kind);
   bool TryReplaceWithUnaryOp(BindInstr* instr,
                              InstanceCallComp* comp,
@@ skipping 86 matching lines @@
  private:
   static void OptimizeRecursive(
       BlockEntryInstr* entry,
       DirectChainedHashMap<BindInstr*>* map);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_OPTIMIZER_H_