Improve register usage for StoreInstanceField.

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 2137 matching lines @@
     inputs_[1] = value;
   }
 
   DECLARE_INSTRUCTION(StoreInstanceField)
   virtual RawAbstractType* CompileType() const;
 
   const Field& field() const { return field_; }
 
   Value* instance() const { return inputs_[0]; }
   Value* value() const { return inputs_[1]; }
-  bool emit_store_barrier() const {
-    return emit_store_barrier_;
+  bool ShouldEmitStoreBarrier() const {
+    return value()->NeedsStoreBuffer() && emit_store_barrier_;
   }
 
   virtual void PrintOperandsTo(BufferFormatter* f) const;
 
   virtual bool CanDeoptimize() const { return false; }
   virtual intptr_t ResultCid() const { return kDynamicCid; }
 
  private:
   const Field& field_;
   const bool emit_store_barrier_;
@@ skipping 88 matching lines @@
     inputs_[2] = value;
   }
 
   DECLARE_INSTRUCTION(StoreIndexed)
   virtual RawAbstractType* CompileType() const;
 
   Value* array() const { return inputs_[0]; }
   Value* index() const { return inputs_[1]; }
   Value* value() const { return inputs_[2]; }
 
-  bool emit_store_barrier() const { return emit_store_barrier_; }
+  bool ShouldEmitStoreBarrier() const {
+    return value()->NeedsStoreBuffer() && emit_store_barrier_;
+  }
 
   virtual bool CanDeoptimize() const { return false; }
   virtual intptr_t ResultCid() const { return kDynamicCid; }
 
  private:
   const bool emit_store_barrier_;
 
   DISALLOW_COPY_AND_ASSIGN(StoreIndexedInstr);
 };
 
@@ skipping 1160 matching lines @@
   ForwardInstructionIterator* current_iterator_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_