[turbofan] Introduce dedicated NumberConvertHoleNaN simplified operator.

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index c43483dd409f877ba44e2aa272362853ef8e6db0..3625f5bd034dbc4d5bf1b31816143be3fed3cb1a 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -248,6 +248,7 @@ class Typer::Visitor : public Reducer {
   static Type* NumberTrunc(Type*, Typer*);
   static Type* NumberToInt32(Type*, Typer*);
   static Type* NumberToUint32(Type*, Typer*);
+  static Type* NumberConvertHoleNaN(Type*, Typer*);
 
   static Type* ObjectIsCallable(Type*, Typer*);
   static Type* ObjectIsNumber(Type*, Typer*);
@@ -556,6 +557,10 @@ Type* Typer::Visitor::NumberToUint32(Type* type, Typer* t) {
   return Type::Unsigned32();
 }
 
+Type* Typer::Visitor::NumberConvertHoleNaN(Type* type, Typer* t) {
+  return Type::Union(type, Type::Undefined(), t->zone());
+}
+
 // Type checks.
 
 Type* Typer::Visitor::ObjectIsCallable(Type* type, Typer* t) {
@@ -1813,6 +1818,10 @@ Type* Typer::Visitor::TypeNumberIsHoleNaN(Node* node) {
   return Type::Boolean();
 }
 
+Type* Typer::Visitor::TypeNumberConvertHoleNaN(Node* node) {
+  return TypeUnaryOp(node, NumberConvertHoleNaN);
+}
+
 // static
 Type* Typer::Visitor::ReferenceEqualTyper(Type* lhs, Type* rhs, Typer* t) {
   if (lhs->IsConstant() && rhs->Is(lhs)) {