Make sure to clear any previously collected field maps.

src/hydrogen.cc

 // Copyright 2013 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 5556 matching lines @@
   } else if (lookup_.IsConstant()) {
     constant_ = handle(lookup_.GetConstantFromMap(*map), isolate());
   }
 
   return true;
 }
 
 
 void HOptimizedGraphBuilder::PropertyAccessInfo::LoadFieldMaps(
     Handle<Map> map) {
+  // Clear any previously collected field maps.
+  field_maps_.Clear();
+
   // Figure out the field type from the accessor map.
   Handle<HeapType> field_type(lookup_.GetFieldTypeFromMap(*map), isolate());
 
   // Collect the (stable) maps from the field type.
   int num_field_maps = field_type->NumClasses();
-  if (num_field_maps == 0) {
-    field_maps_.Clear();
-    return;
-  }
+  if (num_field_maps == 0) return;
   ASSERT(access_.representation().IsHeapObject());
   field_maps_.Reserve(num_field_maps, zone());
   HeapType::Iterator<Map> it = field_type->Classes();
   while (!it.Done()) {
     Handle<Map> field_map = it.Current();
     if (!field_map->is_stable()) {
       field_maps_.Clear();
       return;
     }
     field_maps_.Add(field_map, zone());
@@ skipping 6048 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal