Convert EqualityCompare to StrictCompare if reciever is either null or guaranteed to have default e…

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 137 matching lines @@
                                 MethodRecognizer::Kind recognized_kind);
 
   void HandleRelationalOp(RelationalOpInstr* comp);
 
   // Visit an equality compare.  The current instruction can be the
   // comparison itself or a branch on the comparison.
   template <typename T>
   void HandleEqualityCompare(EqualityCompareInstr* comp,
                              T current_instruction);
 
+  static bool CanStrictifyEqualityCompare(EqualityCompareInstr* call);
+
+  template <typename T>
+  bool StrictifyEqualityCompare(EqualityCompareInstr* compare,
+                                T current_instruction) const;
+
   void OptimizeLeftShiftBitAndSmiOp(Definition* bit_and_instr,
                                     Definition* left_instr,
                                     Definition* right_instr);
 
   void AddToGuardedFields(Field* field);
 
   FlowGraph* flow_graph_;
   GrowableArray<Field*>* guarded_fields_;
 
   DISALLOW_COPY_AND_ASSIGN(FlowGraphOptimizer);
@@ skipping 141 matching lines @@
 // platform.
 class IfConverter : public AllStatic {
  public:
   static void Simplify(FlowGraph* flow_graph);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_OPTIMIZER_H_