Clarify side effects of HTransitionElementsKind.

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 3067 matching lines @@
 
 void HTransitionElementsKind::PrintDataTo(StringStream* stream) {
   object()->PrintNameTo(stream);
   ElementsKind from_kind = original_map()->elements_kind();
   ElementsKind to_kind = transitioned_map()->elements_kind();
   stream->Add(" %p [%s] -> %p [%s]",
               *original_map(),
               ElementsAccessor::ForKind(from_kind)->name(),
               *transitioned_map(),
               ElementsAccessor::ForKind(to_kind)->name());
+  if (IsSimpleMapChangeTransition(from_kind, to_kind)) stream->Add(" (simple)");
 }
 
 
 void HLoadGlobalCell::PrintDataTo(StringStream* stream) {
   stream->Add("[%p]", *cell());
   if (!details_.IsDontDelete()) stream->Add(" (deleteable)");
   if (details_.IsReadOnly()) stream->Add(" (read-only)");
 }
 
 
@@ skipping 899 matching lines @@
       break;
     case kExternalMemory:
       stream->Add("[external-memory]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal