When HBranch sees Smi, it sees Smi.

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 1268 matching lines @@
       ToBooleanStub::UNDEFINED |
       ToBooleanStub::NULL_TYPE |
       ToBooleanStub::SPEC_OBJECT |
       ToBooleanStub::STRING |
       ToBooleanStub::SYMBOL);
   if (expected_input_types_.ContainsAnyOf(tagged_types)) {
     return Representation::Tagged();
   } else if (expected_input_types_.Contains(ToBooleanStub::HEAP_NUMBER)) {
     return Representation::Double();
   } else if (expected_input_types_.Contains(ToBooleanStub::SMI)) {
-    return Representation::Integer32();
+    return Representation::Smi();
   } else {
     return Representation::None();
   }
 }
 
 
 void HCompareMap::PrintDataTo(StringStream* stream) {
   value()->PrintNameTo(stream);
   stream->Add(" (%p)", *map());
   HControlInstruction::PrintDataTo(stream);
@@ skipping 2550 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