Allow merging of monomorphic accesses to tracked fields.

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 3364 matching lines @@
 
 void HParameter::PrintDataTo(StringStream* stream) {
   stream->Add("%u", index());
 }
 
 
 void HLoadNamedField::PrintDataTo(StringStream* stream) {
   object()->PrintNameTo(stream);
   access_.PrintTo(stream);
 
-  if (!map().IsNull()) {
-    stream->Add(" (%p)", *map().handle());
+  if (map_set_.size() != 0) {
+    stream->Add(" [%p", *map_set_.at(0).handle());
+    for (int i = 1; i < map_set_.size(); ++i) {
+      stream->Add(",%p", *map_set_.at(i).handle());
+    }
+    stream->Add("]");
   }
 
   if (HasDependency()) {
     stream->Add(" ");
     dependency()->PrintNameTo(stream);
   }
 }
 
 
 HCheckMaps* HCheckMaps::New(Zone* zone,
@@ skipping 1321 matching lines @@
       break;
     case kExternalMemory:
       stream->Add("[external-memory]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal