[turbofan] Properly recognize and optimize comparisons with the_hole.

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index 5b7a917e7664d9ed471ed30a6d9e0e7e4aed9c68..c4dc3182ef3b86424ade6581e9140b320b932d9f 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -54,12 +54,15 @@ Typer::Typer(Isolate* isolate, Graph* graph, Flags flags,
 
   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),
-                  Type::NullOrUndefined(), 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_,
@@ -697,6 +700,10 @@ Type* Typer::Visitor::JSStrictEqualTyper(Type* lhs, Type* rhs, Typer* t) {
       (lhs->Max() < rhs->Min() || lhs->Min() > rhs->Max())) {
     return t->singleton_false_;
   }
+  if ((lhs->Is(t->singleton_the_hole_) || rhs->Is(t->singleton_the_hole_)) &&
+      !lhs->Maybe(rhs)) {
+    return t->singleton_false_;
+  }
   if (lhs->IsConstant() && rhs->Is(lhs)) {
     // Types are equal and are inhabited only by a single semantic value,
     // which is not nan due to the earlier check.