Separate the checks from StoreInstanceField so that they can be eliminated.

runtime/vm/intermediate_language.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_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 985 matching lines @@
  private:
   const NativeBodyNode& ast_node_;
   const intptr_t try_index_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeCallComp);
 };
 
 
 class LoadInstanceFieldComp : public TemplateComputation<1> {
  public:
+  // Set 'original' to NULL if this it cannot deoptimize.

[regis, 2012/08/21 23:58:34]

if what?

[srdjan, 2012/08/22 00:02:48]

Fixed

   LoadInstanceFieldComp(const Field& field,
                         Value* instance,
-                        InstanceCallComp* original,  // Maybe NULL.
-                        bool can_deoptimize)
-      : field_(field), original_(original), can_deoptimize_(can_deoptimize) {
+                        InstanceCallComp* original)
+      : field_(field), original_(original) {
     ASSERT(instance != NULL);
     inputs_[0] = instance;
   }
 
   DECLARE_COMPUTATION(LoadInstanceField)
 
   const Field& field() const { return field_; }
   Value* instance() const { return inputs_[0]; }
   const InstanceCallComp* original() const { return original_; }
 
   virtual void PrintOperandsTo(BufferFormatter* f) const;
 
-  virtual bool CanDeoptimize() const { return can_deoptimize_; }
+  virtual bool CanDeoptimize() const { return original_ != NULL; }
 
  private:
   const Field& field_;
   const InstanceCallComp* original_;  // For optimizations.
-  const bool can_deoptimize_;
 
   DISALLOW_COPY_AND_ASSIGN(LoadInstanceFieldComp);
 };
 
 
 class StoreInstanceFieldComp : public TemplateComputation<2> {
  public:
+  // Set StoreInstanceFieldComp to NULL if it cannot deoptimize.
   StoreInstanceFieldComp(const Field& field,
                          Value* instance,
                          Value* value,
                          InstanceCallComp* original)  // Maybe NULL.
       : field_(field), original_(original) {
     ASSERT(instance != NULL);
     ASSERT(value != NULL);
     inputs_[0] = instance;
     inputs_[1] = value;
   }
 
   DECLARE_COMPUTATION(StoreInstanceField)
 
   const Field& field() const { return field_; }
 
   Value* instance() const { return inputs_[0]; }
   Value* value() const { return inputs_[1]; }
 
   const InstanceCallComp* original() const { return original_; }
 
   virtual void PrintOperandsTo(BufferFormatter* f) const;
 
-  virtual bool CanDeoptimize() const { return true; }
+  virtual bool CanDeoptimize() const { return original_ != NULL; }
 
  private:
   const Field& field_;
   const InstanceCallComp* original_;  // For optimizations.
 
   DISALLOW_COPY_AND_ASSIGN(StoreInstanceFieldComp);
 };
 
 
 class LoadStaticFieldComp : public TemplateComputation<0> {
@@ skipping 2015 matching lines @@
   ForwardInstructionIterator* current_iterator_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_