Use the property load IC for accessing the array length.

src/arm/lithium-codegen-arm.cc

 // 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 4868 matching lines @@
 void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
   Register scratch = scratch0();
   LOperand* input = instr->value();
   ASSERT(input->IsRegister());
   Register reg = ToRegister(input);
 
   Label success;
   SmallMapList* map_set = instr->hydrogen()->map_set();
   for (int i = 0; i < map_set->length() - 1; i++) {
     Handle<Map> map = map_set->at(i);
-    __ CompareMap(reg, scratch, map, &success, REQUIRE_EXACT_MAP);
+    __ CompareMap(reg, scratch, map, &success, instr->hydrogen()->mode());
     __ b(eq, &success);
   }
   Handle<Map> map = map_set->last();
-  DoCheckMapCommon(reg, scratch, map, REQUIRE_EXACT_MAP, instr->environment());
+  DoCheckMapCommon(reg, scratch, map, instr->hydrogen()->mode(),
+                   instr->environment());
   __ bind(&success);
 }
 
 
 void LCodeGen::DoClampDToUint8(LClampDToUint8* instr) {
   DoubleRegister value_reg = ToDoubleRegister(instr->unclamped());
   Register result_reg = ToRegister(instr->result());
   DoubleRegister temp_reg = ToDoubleRegister(instr->temp());
   __ ClampDoubleToUint8(result_reg, value_reg, temp_reg);
 }
@@ skipping 811 matching lines @@
   __ sub(scratch, result, Operand(index, LSL, kPointerSizeLog2 - kSmiTagSize));
   __ ldr(result, FieldMemOperand(scratch,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal