[date] Refactor the %_DateField intrinsic to be optimizable.

src/hydrogen-instructions.h

 // Copyright 2012 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.
 
 #ifndef V8_HYDROGEN_INSTRUCTIONS_H_
 #define V8_HYDROGEN_INSTRUCTIONS_H_
 
 #include <cstring>
 #include <iosfwd>
 
@@ skipping 2857 matching lines @@
   Unique<HeapObject> object_;
   bool object_in_new_space_;
 };
 
 
 class HCheckInstanceType final : public HUnaryOperation {
  public:
   enum Check {
     IS_SPEC_OBJECT,
     IS_JS_ARRAY,
+    IS_JS_DATE,
     IS_STRING,
     IS_INTERNALIZED_STRING,
-    LAST_INTERVAL_CHECK = IS_JS_ARRAY
+    LAST_INTERVAL_CHECK = IS_JS_DATE
   };
 
   DECLARE_INSTRUCTION_FACTORY_P2(HCheckInstanceType, HValue*, Check);
 
   std::ostream& PrintDataTo(std::ostream& os) const override;  // NOLINT
 
   Representation RequiredInputRepresentation(int index) override {
     return Representation::Tagged();
   }
 
   HType CalculateInferredType() override {
     switch (check_) {
       case IS_SPEC_OBJECT: return HType::JSObject();
       case IS_JS_ARRAY: return HType::JSArray();
+      case IS_JS_DATE:
+        return HType::JSObject();
       case IS_STRING: return HType::String();
       case IS_INTERNALIZED_STRING: return HType::String();
     }
     UNREACHABLE();
     return HType::Tagged();
   }
 
   HValue* Canonicalize() override;
 
   bool is_interval_check() const { return check_ <= LAST_INTERVAL_CHECK; }
@@ skipping 5000 matching lines @@
 };
 
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_