Unify the handling of comparinsons against null and undefined.

src/hydrogen-instructions.h

 // Copyright 2011 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 100 matching lines @@
   V(GlobalObject)                              \
   V(GlobalReceiver)                            \
   V(Goto)                                      \
   V(HasCachedArrayIndexAndBranch)              \
   V(HasInstanceTypeAndBranch)                  \
   V(In)                                        \
   V(InstanceOf)                                \
   V(InstanceOfKnownGlobal)                     \
   V(InvokeFunction)                            \
   V(IsConstructCallAndBranch)                  \
-  V(IsNullAndBranch)                           \
+  V(IsNilAndBranch)                            \
   V(IsObjectAndBranch)                         \
   V(IsSmiAndBranch)                            \
   V(IsUndetectableAndBranch)                   \
   V(JSArrayLength)                             \
   V(LeaveInlined)                              \
   V(LoadContextSlot)                           \
   V(LoadElements)                              \
   V(LoadExternalArrayPointer)                  \
   V(LoadFunctionPrototype)                     \
   V(LoadGlobalCell)                            \
@@ skipping 2502 matching lines @@
   }
 
   DECLARE_CONCRETE_INSTRUCTION(CompareConstantEqAndBranch);
 
  private:
   const Token::Value op_;
   const int right_;
 };
 
 
-class HIsNullAndBranch: public HUnaryControlInstruction {
+class HIsNilAndBranch: public HUnaryControlInstruction {
  public:
-  HIsNullAndBranch(HValue* value, bool is_strict)
-      : HUnaryControlInstruction(value, NULL, NULL), is_strict_(is_strict) { }
+  HIsNilAndBranch(HValue* value, EqualityKind kind, NilValue nil)
+      : HUnaryControlInstruction(value, NULL, NULL), kind_(kind), nil_(nil) { }
 
-  bool is_strict() const { return is_strict_; }
+  EqualityKind kind() const { return kind_; }
+  NilValue nil() const { return nil_; }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
   }
 
-  DECLARE_CONCRETE_INSTRUCTION(IsNullAndBranch)
+  DECLARE_CONCRETE_INSTRUCTION(IsNilAndBranch)
 
  private:
-  bool is_strict_;
+  EqualityKind kind_;
+  NilValue nil_;
 };
 
 
 class HIsObjectAndBranch: public HUnaryControlInstruction {
  public:
   explicit HIsObjectAndBranch(HValue* value)
     : HUnaryControlInstruction(value, NULL, NULL) { }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();
@@ skipping 1532 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(In)
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_