[turbofan] Introduce CheckHole and CheckHoleNaN operators.

src/compiler/simplified-operator.h

Index: src/compiler/simplified-operator.h
diff --git a/src/compiler/simplified-operator.h b/src/compiler/simplified-operator.h
index f4a3cb9bfe0a6f7f53dad58337ed39e18520ff0d..3dd6ccebbb982bb01117d0190bd004f73e203944 100644
--- a/src/compiler/simplified-operator.h
+++ b/src/compiler/simplified-operator.h
@@ -103,6 +103,18 @@ std::ostream& operator<<(std::ostream&, ElementAccess const&);
 
 ElementAccess const& ElementAccessOf(const Operator* op) WARN_UNUSED_RESULT;
 
+// Mode of operation for the check-hole operators.
+enum class CheckHoleMode : uint8_t {
+  kAllowReturnHole,  // Allow to return the hole either as NaN or undefined.
+  kNeverReturnHole,  // Never return the hole (deoptimize instead).
+};
+
+size_t hash_value(CheckHoleMode);
+
+std::ostream& operator<<(std::ostream&, CheckHoleMode);
+
+CheckHoleMode CheckHoleModeOf(const Operator*) WARN_UNUSED_RESULT;
+
 Type* TypeOf(const Operator* op) WARN_UNUSED_RESULT;
 
 BinaryOperationHints::Hint BinaryOperationHintOf(const Operator* op);
@@ -164,8 +176,6 @@ class SimplifiedOperatorBuilder final : public ZoneObject {
   const Operator* NumberTrunc();
   const Operator* NumberToInt32();
   const Operator* NumberToUint32();
-  const Operator* NumberIsHoleNaN();
-  const Operator* NumberConvertHoleNaN();
 
   const Operator* NumberSilenceNaN();
 
@@ -202,6 +212,8 @@ class SimplifiedOperatorBuilder final : public ZoneObject {
   const Operator* CheckedTaggedToInt32();
   const Operator* CheckedTaggedToFloat64();
 
+  const Operator* CheckHole(CheckHoleMode);
+  const Operator* CheckHoleNaN(CheckHoleMode);
   const Operator* CheckIf();
 
   const Operator* ObjectIsCallable();