Make constant propagation to fold x == x and re-run type propagation for better range analysis.

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 24 matching lines @@
   // shift can be a truncating Smi shift-left and result is always Smi.
   void TryOptimizeLeftShiftWithBitAndPattern();
 
   // Returns true if any instructions were canonicalized away.
   bool Canonicalize();
 
   void EliminateDeadPhis();
 
   void SelectRepresentations();
 
-  void UnboxPhis();
-
   void InferSmiRanges();
 
   void AnalyzeTryCatch();
 
   // Remove environments from the instructions which do not deoptimize.
   void EliminateEnvironments();
 
   virtual void VisitStaticCall(StaticCallInstr* instr);
   virtual void VisitInstanceCall(InstanceCallInstr* instr);
   virtual void VisitRelationalOp(RelationalOpInstr* instr);
@@ skipping 310 matching lines @@
 // Optimize spill stores inside try-blocks by identifying values that always
 // contain a single known constant at catch block entry.
 class TryCatchAnalyzer : public AllStatic {
  public:
   static void Optimize(FlowGraph* flow_graph);
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_OPTIMIZER_H_