Revert change to always call builtins for Array functions....

src/ic.cc

 // Copyright 2006-2009 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 440 matching lines @@
       if (IsContextual(object)) {
         return ReferenceError("not_defined", name);
       }
       return TypeError("undefined_method", object, name);
     }
   }
 
   ASSERT(result != Heap::the_hole_value());
 
   if (result->IsJSFunction()) {
+    // Check if there is an optimized (builtin) version of the function.
+    // Ignored this will degrade performance for some Array functions.
+    // Please note we only return the optimized function iff
+    // the JSObject has FastElements.
+    if (object->IsJSObject() && JSObject::cast(*object)->HasFastElements()) {
+      Object* opt = Top::LookupSpecialFunction(JSObject::cast(*object),
+                                               lookup.holder(),
+                                               JSFunction::cast(result));
+      if (opt->IsJSFunction()) return opt;
+    }
+
 #ifdef ENABLE_DEBUGGER_SUPPORT
     // Handle stepping into a function if step into is active.
     if (Debug::StepInActive()) {
       // Protect the result in a handle as the debugger can allocate and might
       // cause GC.
       HandleScope scope;
       Handle<JSFunction> function(JSFunction::cast(result));
       Debug::HandleStepIn(function, object, fp(), false);
       return *function;
     }
@@ skipping 1050 matching lines @@
 #undef ADDR
 };
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) {
   return IC_utilities[id];
 }
 
 
 } }  // namespace v8::internal