Eliminate redundant smi checks

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 1694 matching lines @@
   stream->Add(".");
   stream->Add(*String::cast(*name())->ToCString());
 }
 
 
 void HLoadKeyedFastElement::PrintDataTo(StringStream* stream) {
   object()->PrintNameTo(stream);
   stream->Add("[");
   key()->PrintNameTo(stream);
   stream->Add("]");
-  if (hole_check_mode_ == PERFORM_HOLE_CHECK) {
+  if (RequiresHoleCheck()) {
     stream->Add(" check_hole");
   }
 }
 
 
 bool HLoadKeyedFastElement::RequiresHoleCheck() {
-  if (hole_check_mode_ == OMIT_HOLE_CHECK) {
+  if (IsFastPackedElementsKind(elements_kind())) {
     return false;
   }
 
   for (HUseIterator it(uses()); !it.Done(); it.Advance()) {
     HValue* use = it.value();
     if (!use->IsChange()) return true;
   }
 
   return false;
 }
@@ skipping 25 matching lines @@
       HForInCacheArray* names_cache =
           HForInCacheArray::cast(key_load->object());
 
       if (names_cache->enumerable() == object()) {
         HForInCacheArray* index_cache =
             names_cache->index_cache();
         HCheckMapValue* map_check =
             new(block()->zone()) HCheckMapValue(object(), names_cache->map());
         HInstruction* index = new(block()->zone()) HLoadKeyedFastElement(
             index_cache,
-            key_load->key(),
-            OMIT_HOLE_CHECK);
+            key_load->key());
         map_check->InsertBefore(this);
         index->InsertBefore(this);
         HLoadFieldByIndex* load = new(block()->zone()) HLoadFieldByIndex(
             object(), index);
         load->InsertBefore(this);
         return load;
       }
     }
   }
 
@@ skipping 698 matching lines @@
 
 
 void HCheckPrototypeMaps::Verify() {
   HInstruction::Verify();
   ASSERT(HasNoUses());
 }
 
 #endif
 
 } }  // namespace v8::internal