[turbofan] Improve fast case of JSInstanceOf lowering.

test/unittests/compiler/js-typed-lowering-unittest.cc

Index: test/unittests/compiler/js-typed-lowering-unittest.cc
diff --git a/test/unittests/compiler/js-typed-lowering-unittest.cc b/test/unittests/compiler/js-typed-lowering-unittest.cc
index 72c582525e103c251843997638a7b38922710b71..b66fdaab0b35d93f7cf0c1230cf10cd45b5b0e44 100644
--- a/test/unittests/compiler/js-typed-lowering-unittest.cc
+++ b/test/unittests/compiler/js-typed-lowering-unittest.cc
@@ -1026,43 +1026,18 @@ TEST_F(JSTypedLoweringTest, JSSubtractSmis) {
 // Test that instanceOf is reduced if and only if the right-hand side is a
 // function constant. Functional correctness is ensured elsewhere.
 
-TEST_F(JSTypedLoweringTest, JSInstanceOfSpecializationWithoutSmiCheck) {
+TEST_F(JSTypedLoweringTest, JSInstanceOfSpecialization) {
   Node* const context = Parameter(Type::Any());
   Node* const frame_state = EmptyFrameState();
   Node* const effect = graph()->start();
   Node* const control = graph()->start();
 
-  // Reduce if left-hand side is known to be an object.
-  Node* instanceOf =
-      graph()->NewNode(javascript()->InstanceOf(), Parameter(Type::Object(), 0),
-                       HeapConstant(isolate()->object_function()), context,
-                       frame_state, effect, control);
-  Node* dummy = graph()->NewNode(javascript()->ToObject(), instanceOf, context,
-                                 frame_state, effect, control);
-  Reduction r = Reduce(instanceOf);
-  ASSERT_TRUE(r.Changed());
-  ASSERT_EQ(r.replacement(), dummy->InputAt(0));
-  ASSERT_NE(instanceOf, dummy->InputAt(0));
-}
-
-
-TEST_F(JSTypedLoweringTest, JSInstanceOfSpecializationWithSmiCheck) {
-  Node* const context = Parameter(Type::Any());
-  Node* const frame_state = EmptyFrameState();
-  Node* const effect = graph()->start();
-  Node* const control = graph()->start();
-
-  // Reduce if left-hand side could be a Smi.
   Node* instanceOf =
       graph()->NewNode(javascript()->InstanceOf(), Parameter(Type::Any(), 0),
                        HeapConstant(isolate()->object_function()), context,
                        frame_state, effect, control);
-  Node* dummy = graph()->NewNode(javascript()->ToObject(), instanceOf, context,
-                                 frame_state, effect, control);
   Reduction r = Reduce(instanceOf);
   ASSERT_TRUE(r.Changed());
-  ASSERT_EQ(r.replacement(), dummy->InputAt(0));
-  ASSERT_NE(instanceOf, dummy->InputAt(0));
 }