HBoundsCheck shouldn't ignore Tagged input representations unconditionally

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 1138 matching lines @@
   }
 }
 
 
 void HBoundsCheck::InferRepresentation(HInferRepresentation* h_infer) {
   ASSERT(CheckFlag(kFlexibleRepresentation));
   HValue* actual_index = index()->ActualValue();
   HValue* actual_length = length()->ActualValue();
   Representation index_rep = actual_index->representation();
   Representation length_rep = actual_length->representation();
-  if (index_rep.IsTagged()) index_rep = Representation::Smi();
-  if (length_rep.IsTagged()) length_rep = Representation::Smi();
+  if (index_rep.IsTagged() && actual_index->type().IsSmi()) {
+    index_rep = Representation::Smi();
+  }
+  if (length_rep.IsTagged() && actual_length->type().IsSmi()) {
+    length_rep = Representation::Smi();
+  }
   Representation r = index_rep.generalize(length_rep);
   if (r.is_more_general_than(Representation::Integer32())) {
     r = Representation::Integer32();
   }
   UpdateRepresentation(r, h_infer, "boundscheck");
 }
 
 
 bool HBoundsCheckBaseIndexInformation::IsRelationTrueInternal(
     NumericRelation relation,
@@ skipping 2710 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