Fix the hole loading optimization.

src/hydrogen-instructions.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 2702 matching lines @@
     if (IsFastDoubleElementsKind(elements_kind())) {
       return AllUsesCanTreatHoleAsNaN();
     }
     return true;
   }
 
   if (IsFastDoubleElementsKind(elements_kind())) {
     return false;
   }
 
+  // Holes are only returned as tagged values.
+  if (!representation().IsTagged()) {
+    return false;
+  }
+
   for (HUseIterator it(uses()); !it.Done(); it.Advance()) {
     HValue* use = it.value();
-    if (!use->IsChange() || !HChange::cast(use)->to().IsDouble()) {
-      return false;
-    }
+    if (!use->IsChange()) return false;
   }
 
   return true;
 }
 
 
 bool HLoadKeyed::AllUsesCanTreatHoleAsNaN() const {
   if (!IsFastDoubleElementsKind(elements_kind())) {
     return false;
   }
@@ skipping 1052 matching lines @@
     case kBackingStore:
       if (!name_.is_null()) stream->Add(*String::cast(*name_)->ToCString());
       stream->Add("[backing-store]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal