[compiler] Drop the CompareNilIC.

src/code-stubs.cc

Index: src/code-stubs.cc
diff --git a/src/code-stubs.cc b/src/code-stubs.cc
index 4e5efcd8e02bd115a9c303cba78619d552a07198..b56beb8d524bf449d67bc9bf34705e586f97727a 100644
--- a/src/code-stubs.cc
+++ b/src/code-stubs.cc
@@ -451,28 +451,6 @@ void CompareICStub::Generate(MacroAssembler* masm) {
 }
 
 
-void CompareNilICStub::UpdateStatus(Handle<Object> object) {
-  State state = this->state();
-  DCHECK(!state.Contains(GENERIC));
-  State old_state = state;
-  if (object->IsNull()) {
-    state.Add(NULL_TYPE);
-  } else if (object->IsUndefined()) {
-    state.Add(UNDEFINED);
-  } else if (object->IsUndetectableObject() || object->IsSmi()) {
-    state.RemoveAll();
-    state.Add(GENERIC);
-  } else if (IsMonomorphic()) {
-    state.RemoveAll();
-    state.Add(GENERIC);
-  } else {
-    state.Add(MONOMORPHIC_MAP);
-  }
-  TraceTransition(old_state, state);
-  set_sub_minor_key(TypesBits::update(sub_minor_key(), state.ToIntegral()));
-}
-
-
 Handle<Code> TurboFanCodeStub::GenerateCode() {
   const char* name = CodeStub::MajorName(MajorKey());
   Zone zone;
@@ -508,17 +486,6 @@ void HydrogenCodeStub::TraceTransition(StateType from, StateType to) {
 }
 
 
-void CompareNilICStub::PrintBaseName(std::ostream& os) const {  // NOLINT
-  CodeStub::PrintBaseName(os);
-  os << ((nil_value() == kNullValue) ? "(NullValue)" : "(UndefinedValue)");
-}
-
-
-void CompareNilICStub::PrintState(std::ostream& os) const {  // NOLINT
-  os << state();
-}
-
-
 // TODO(svenpanne) Make this a real infix_ostream_iterator.
 class SimpleListPrinter {
  public:
@@ -539,45 +506,6 @@ class SimpleListPrinter {
 };
 
 
-std::ostream& operator<<(std::ostream& os, const CompareNilICStub::State& s) {
-  os << "(";
-  SimpleListPrinter p(os);
-  if (s.IsEmpty()) p.Add("None");
-  if (s.Contains(CompareNilICStub::UNDEFINED)) p.Add("Undefined");
-  if (s.Contains(CompareNilICStub::NULL_TYPE)) p.Add("Null");
-  if (s.Contains(CompareNilICStub::MONOMORPHIC_MAP)) p.Add("MonomorphicMap");
-  if (s.Contains(CompareNilICStub::GENERIC)) p.Add("Generic");
-  return os << ")";
-}
-
-
-Type* CompareNilICStub::GetType(Zone* zone, Handle<Map> map) {
-  State state = this->state();
-  if (state.Contains(CompareNilICStub::GENERIC)) return Type::Any();
-
-  Type* result = Type::None();
-  if (state.Contains(CompareNilICStub::UNDEFINED)) {
-    result = Type::Union(result, Type::Undefined(), zone);
-  }
-  if (state.Contains(CompareNilICStub::NULL_TYPE)) {
-    result = Type::Union(result, Type::Null(), zone);
-  }
-  if (state.Contains(CompareNilICStub::MONOMORPHIC_MAP)) {
-    Type* type = map.is_null() ? Type::Detectable() : Type::Class(map, zone);
-    result = Type::Union(result, type, zone);
-  }
-
-  return result;
-}
-
-
-Type* CompareNilICStub::GetInputType(Zone* zone, Handle<Map> map) {
-  Type* output_type = GetType(zone, map);
-  Type* nil_type = nil_value() == kNullValue ? Type::Null() : Type::Undefined();
-  return Type::Union(output_type, nil_type, zone);
-}
-
-
 void CallICStub::PrintState(std::ostream& os) const {  // NOLINT
   os << state();
 }
@@ -739,13 +667,6 @@ void AllocateInNewSpaceStub::InitializeDescriptor(
 }
 
 
-void CompareNilICStub::InitializeDescriptor(CodeStubDescriptor* descriptor) {
-  descriptor->Initialize(FUNCTION_ADDR(Runtime_CompareNilIC_Miss));
-  descriptor->SetMissHandler(ExternalReference(
-      Runtime::FunctionForId(Runtime::kCompareNilIC_Miss), isolate()));
-}
-
-
 void ToBooleanStub::InitializeDescriptor(CodeStubDescriptor* descriptor) {
   descriptor->Initialize(FUNCTION_ADDR(Runtime_ToBooleanIC_Miss));
   descriptor->SetMissHandler(ExternalReference(