Revert of [compiler] Drop the CompareNilIC.

src/compiler/typer.cc

 // Copyright 2014 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/compiler/typer.h"
 
 #include "src/base/flags.h"
 #include "src/bootstrapper.h"
 #include "src/compilation-dependencies.h"
 #include "src/compiler/common-operator.h"
@@ skipping 39 matching lines @@
                   Type::MinusZeroOrNaN(), zone);
   DCHECK(!truncating_to_zero->Maybe(Type::Integral32()));
 
   singleton_false_ = Type::Constant(factory->false_value(), zone);
   singleton_true_ = Type::Constant(factory->true_value(), zone);
   singleton_the_hole_ = Type::Constant(factory->the_hole_value(), zone);
   signed32ish_ = Type::Union(Type::Signed32(), truncating_to_zero, zone);
   unsigned32ish_ = Type::Union(Type::Unsigned32(), truncating_to_zero, zone);
   falsish_ = Type::Union(
       Type::Undetectable(),
-      Type::Union(Type::Union(singleton_false_, cache_.kZeroish, zone),
-                  singleton_the_hole_, zone),
+      Type::Union(
+          Type::Union(Type::Union(singleton_false_, cache_.kZeroish, zone),
+                      Type::NullOrUndefined(), zone),
+          singleton_the_hole_, zone),
       zone);
   truish_ = Type::Union(
       singleton_true_,
       Type::Union(Type::DetectableReceiver(), Type::Symbol(), zone), zone);
 
   decorator_ = new (zone) Decorator(this);
   graph_->AddDecorator(decorator_);
 }
 
 
@@ skipping 163 matching lines @@
   static Type* ToName(Type*, Typer*);
   static Type* ToNumber(Type*, Typer*);
   static Type* ToObject(Type*, Typer*);
   static Type* ToString(Type*, Typer*);
   static Type* NumberToInt32(Type*, Typer*);
   static Type* NumberToUint32(Type*, Typer*);
 
   static Type* ObjectIsNumber(Type*, Typer*);
   static Type* ObjectIsReceiver(Type*, Typer*);
   static Type* ObjectIsSmi(Type*, Typer*);
-  static Type* ObjectIsUndetectable(Type*, Typer*);
 
   static Type* JSAddRanger(RangeType*, RangeType*, Typer*);
   static Type* JSSubtractRanger(RangeType*, RangeType*, Typer*);
   static Type* JSDivideRanger(RangeType*, RangeType*, Typer*);
   static Type* JSModulusRanger(RangeType*, RangeType*, Typer*);
 
   static ComparisonOutcome JSCompareTyper(Type*, Type*, Typer*);
 
 #define DECLARE_METHOD(x) static Type* x##Typer(Type*, Type*, Typer*);
   JS_SIMPLE_BINOP_LIST(DECLARE_METHOD)
@@ skipping 205 matching lines @@
   }
   return Type::Number();
 }
 
 
 // static
 Type* Typer::Visitor::ToObject(Type* type, Typer* t) {
   // ES6 section 7.1.13 ToObject ( argument )
   if (type->Is(Type::Receiver())) return type;
   if (type->Is(Type::Primitive())) return Type::OtherObject();
-  if (!type->Maybe(Type::OtherUndetectable())) {
-    return Type::DetectableReceiver();
-  }
+  if (!type->Maybe(Type::Undetectable())) return Type::DetectableReceiver();
   return Type::Receiver();
 }
 
 
 // static
 Type* Typer::Visitor::ToString(Type* type, Typer* t) {
   // ES6 section 7.1.12 ToString ( argument )
   type = ToPrimitive(type, t);
   if (type->Is(Type::String())) return type;
   return Type::String();
@@ skipping 42 matching lines @@
   return Type::Boolean();
 }
 
 
 Type* Typer::Visitor::ObjectIsSmi(Type* type, Typer* t) {
   if (type->Is(Type::TaggedSigned())) return t->singleton_true_;
   if (type->Is(Type::TaggedPointer())) return t->singleton_false_;
   return Type::Boolean();
 }
 
-
-Type* Typer::Visitor::ObjectIsUndetectable(Type* type, Typer* t) {
-  if (type->Is(Type::Undetectable())) return t->singleton_true_;
-  if (!type->Maybe(Type::Undetectable())) return t->singleton_false_;
-  return Type::Boolean();
-}
-
 
 // -----------------------------------------------------------------------------
 
 
 // Control operators.
 
 Type* Typer::Visitor::TypeStart(Node* node) { return Type::Internal(); }
 
 Type* Typer::Visitor::TypeIfException(Node* node) { return Type::Any(); }
 
@@ skipping 619 matching lines @@
 Type* Typer::Visitor::JSTypeOfTyper(Type* type, Typer* t) {
   Factory* const f = t->isolate()->factory();
   if (type->Is(Type::Boolean())) {
     return Type::Constant(f->boolean_string(), t->zone());
   } else if (type->Is(Type::Number())) {
     return Type::Constant(f->number_string(), t->zone());
   } else if (type->Is(Type::String())) {
     return Type::Constant(f->string_string(), t->zone());
   } else if (type->Is(Type::Symbol())) {
     return Type::Constant(f->symbol_string(), t->zone());
-  } else if (type->Is(Type::Union(Type::Undefined(), Type::OtherUndetectable(),
+  } else if (type->Is(Type::Union(Type::Undefined(), Type::Undetectable(),
                                   t->zone()))) {
     return Type::Constant(f->undefined_string(), t->zone());
   } else if (type->Is(Type::Null())) {
     return Type::Constant(f->object_string(), t->zone());
   } else if (type->Is(Type::Function())) {
     return Type::Constant(f->function_string(), t->zone());
   } else if (type->IsConstant()) {
     return Type::Constant(
         Object::TypeOf(t->isolate(), type->AsConstant()->Value()), t->zone());
   }
@@ skipping 733 matching lines @@
 Type* Typer::Visitor::TypeObjectIsReceiver(Node* node) {
   return TypeUnaryOp(node, ObjectIsReceiver);
 }
 
 
 Type* Typer::Visitor::TypeObjectIsSmi(Node* node) {
   return TypeUnaryOp(node, ObjectIsSmi);
 }
 
 
-Type* Typer::Visitor::TypeObjectIsUndetectable(Node* node) {
-  return TypeUnaryOp(node, ObjectIsUndetectable);
-}
-
-
 // Machine operators.
 
 Type* Typer::Visitor::TypeLoad(Node* node) { return Type::Any(); }
 
 Type* Typer::Visitor::TypeStackSlot(Node* node) { return Type::Any(); }
 
 Type* Typer::Visitor::TypeStore(Node* node) {
   UNREACHABLE();
   return nullptr;
 }
@@ skipping 505 matching lines @@
   }
   if (Type::IsInteger(*value)) {
     return Type::Range(value->Number(), value->Number(), zone());
   }
   return Type::Constant(value, zone());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8