Simplify the LookupIterator

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/hydrogen.h"
 
 #include <algorithm>
 
 #include "src/v8.h"
 
@@ skipping 5289 matching lines @@
     case LookupIterator::ACCESSOR:
     case LookupIterator::ACCESS_CHECK:
     case LookupIterator::INTERCEPTOR:
     case LookupIterator::NOT_FOUND:
       return kUseGeneric;
     case LookupIterator::DATA:
       if (access_type == STORE && it->IsReadOnly()) return kUseGeneric;
       return kUseCell;
     case LookupIterator::JSPROXY:
     case LookupIterator::TRANSITION:
-    case LookupIterator::UNKNOWN:
       UNREACHABLE();
   }
   UNREACHABLE();
   return kUseGeneric;
 }
 
 
 HValue* HOptimizedGraphBuilder::BuildContextChainWalk(Variable* var) {
   DCHECK(var->IsContextSlot());
   HValue* context = environment()->context();
@@ skipping 7170 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal