Add stack check in loops so that loops can be stopped. Optimize relational operations.

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"
 
 namespace dart {
 
 template <typename T> class GrowableArray;
 
 class FlowGraphOptimizer : public FlowGraphVisitor {
  public:
   explicit FlowGraphOptimizer(const GrowableArray<BlockEntryInstr*>& blocks)
       : FlowGraphVisitor(blocks) {}
   virtual ~FlowGraphOptimizer() {}
 
   void ApplyICData();
 
   virtual void VisitInstanceCall(InstanceCallComp* comp);
   virtual void VisitInstanceSetter(InstanceSetterComp* comp);
   virtual void VisitLoadIndexed(LoadIndexedComp* comp);
+  virtual void VisitRelationalOp(RelationalOpComp* comp);
 
   virtual void VisitDo(DoInstr* instr);
   virtual void VisitBind(BindInstr* instr);
 
  private:
   void VisitBlocks();
 
   void TryReplaceWithBinaryOp(InstanceCallComp* comp, Token::Kind op_kind);
   void TryReplaceWithUnaryOp(InstanceCallComp* comp, Token::Kind op_kind);
 
   void TryInlineInstanceGetter(InstanceCallComp* comp);
   void TryInlineInstanceSetter(InstanceSetterComp* comp);
 
   DISALLOW_COPY_AND_ASSIGN(FlowGraphOptimizer);
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_OPTIMIZER_H_