Add "has fast elements" bit to maps and use it in inlined keyed loads.

src/arm/codegen-arm.h

 // Copyright 2010 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 258 matching lines @@
 
   void AddDeferred(DeferredCode* code) { deferred_.Add(code); }
 
   static const int kUnknownIntValue = -1;
 
   // If the name is an inline runtime function call return the number of
   // expected arguments. Otherwise return -1.
   static int InlineRuntimeCallArgumentsCount(Handle<String> name);
 
   // Constants related to patching of inlined load/store.
-  static const int kInlinedKeyedLoadInstructionsAfterPatch = 17;
+  static int GetInlinedKeyedLoadInstructionsAfterPatch() {
+    return FLAG_debug_code ? 27 : 13;
+  }
   static const int kInlinedKeyedStoreInstructionsAfterPatch = 5;
 
  private:
   // Construction/Destruction
   explicit CodeGenerator(MacroAssembler* masm);
 
   // Accessors
   inline bool is_eval();
   inline Scope* scope();
 
@@ skipping 696 matching lines @@
     return ObjectBits::encode(object_.code()) |
            OffsetBits::encode(offset_.code()) |
            ScratchBits::encode(scratch_.code());
   }
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_CODEGEN_ARM_H_