Retrying r10475 (now with null check):

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 {
@@ skipping 58 matching lines @@
 
 
 class ParsedFunction;
 
 
 class FlowGraphTypePropagator : public FlowGraphVisitor {
  public:
   FlowGraphTypePropagator(const ParsedFunction& parsed_function,
                           const GrowableArray<BlockEntryInstr*>& blocks)
       : FlowGraphVisitor(blocks),
-        parsed_function_(parsed_function) { }
-  virtual ~FlowGraphTypePropagator() {}
+        parsed_function_(parsed_function),
+        still_changing_(false) { }
+  virtual ~FlowGraphTypePropagator() { }
 
   const ParsedFunction& parsed_function() const { return parsed_function_; }
 
   void PropagateTypes();
 
   virtual void VisitAssertAssignable(AssertAssignableComp* comp,
                                      BindInstr* instr);
 
-  virtual void VisitBind(BindInstr* instr);
+  virtual void VisitGraphEntry(GraphEntryInstr* graph_entry);
+  virtual void VisitJoinEntry(JoinEntryInstr* join_entry);
+  virtual void VisitBind(BindInstr* bind);
+  virtual void VisitPhi(PhiInstr* phi);
+  virtual void VisitParameter(ParameterInstr* param);
 
  private:
   const ParsedFunction& parsed_function_;
+  bool still_changing_;
   DISALLOW_COPY_AND_ASSIGN(FlowGraphTypePropagator);
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_OPTIMIZER_H_