Again reland "Refine expression typing, esp. by propagating range information."

src/compiler/js-typed-lowering.cc

Index: src/compiler/js-typed-lowering.cc
diff --git a/src/compiler/js-typed-lowering.cc b/src/compiler/js-typed-lowering.cc
index 886846eaddd193a13b9fab13e81176f00da2b615..b63d2325aaf3c939862f0c0826f3bd58973cc572 100644
--- a/src/compiler/js-typed-lowering.cc
+++ b/src/compiler/js-typed-lowering.cc
@@ -383,16 +383,6 @@ Reduction JSTypedLowering::ReduceJSStrictEqual(Node* node, bool invert) {
                                          : jsgraph()->TrueConstant());
     }
   }
-  /* TODO(neis): This is currently unsound.
-  if (!r.left_type()->Maybe(r.right_type())) {
-    // Type intersection is empty; === is always false unless both
-    // inputs could be strings (one internalized and one not).
-    if (r.OneInputCannotBe(Type::String())) {
-      return ReplaceEagerly(node, invert ? jsgraph()->TrueConstant()
-                                         : jsgraph()->FalseConstant());
-    }
-  }
-  */
   if (r.OneInputIs(Type::Undefined())) {
     return r.ChangeToPureOperator(
         simplified()->ReferenceEqual(Type::Undefined()), invert);