Use the property load IC for accessing the array length.

src/objects-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4657 matching lines @@
 
 
 bool Code::contains(byte* inner_pointer) {
   return (address() <= inner_pointer) && (inner_pointer <= address() + Size());
 }
 
 
 ACCESSORS(JSArray, length, Object, kLengthOffset)
 
 
+PropertyIndex JSArray::ArrayLengthIndex() {
+  return PropertyIndex::NewHeaderIndex(kLengthOffset / kPointerSize);
+}
+
+
 ACCESSORS(JSRegExp, data, Object, kDataOffset)
 
 
 JSRegExp::Type JSRegExp::TypeTag() {
   Object* data = this->data();
   if (data->IsUndefined()) return JSRegExp::NOT_COMPILED;
   Smi* smi = Smi::cast(FixedArray::cast(data)->get(kTagIndex));
   return static_cast<JSRegExp::Type>(smi->value());
 }
 
@@ skipping 861 matching lines @@
 #undef WRITE_UINT32_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_