[turbofan] Optimize tagged conversion based on type.

test/unittests/compiler/change-lowering-unittest.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/code-stubs.h"
 #include "src/compiler/change-lowering.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/simplified-operator.h"
@@ skipping 106 matching lines @@
 
 
 TARGET_TEST_P(ChangeLoweringCommonTest, ChangeBoolToBit) {
   Node* value = Parameter(Type::Number());
   Reduction r =
       Reduce(graph()->NewNode(simplified()->ChangeBoolToBit(), value));
   ASSERT_TRUE(r.Changed());
   EXPECT_THAT(r.replacement(), IsWordEqual(value, IsTrueConstant()));
 }
 
-
-TARGET_TEST_P(ChangeLoweringCommonTest, ChangeInt32ToTaggedWithSignedSmall) {
+TARGET_TEST_P(ChangeLoweringCommonTest, ChangeInt31ToTagged) {
   Node* value = Parameter(Type::SignedSmall());
   Reduction r =
-      Reduce(graph()->NewNode(simplified()->ChangeInt32ToTagged(), value));
+      Reduce(graph()->NewNode(simplified()->ChangeInt31ToTagged(), value));
   ASSERT_TRUE(r.Changed());
   EXPECT_THAT(r.replacement(), IsChangeInt32ToSmi(value));
 }
 
-
-TARGET_TEST_P(ChangeLoweringCommonTest, ChangeUint32ToTaggedWithUnsignedSmall) {
-  Node* value = Parameter(Type::UnsignedSmall());
-  Reduction r =
-      Reduce(graph()->NewNode(simplified()->ChangeUint32ToTagged(), value));
-  ASSERT_TRUE(r.Changed());
-  EXPECT_THAT(r.replacement(), IsChangeUint32ToSmi(value));
-}
-
-
 TARGET_TEST_P(ChangeLoweringCommonTest, ChangeTaggedToInt32WithTaggedSigned) {
   Node* value = Parameter(Type::TaggedSigned());
   Reduction r =
       Reduce(graph()->NewNode(simplified()->ChangeTaggedToInt32(), value));
   ASSERT_TRUE(r.Changed());
   EXPECT_THAT(r.replacement(), IsChangeSmiToInt32(value));
 }
 
 TARGET_TEST_P(ChangeLoweringCommonTest, ChangeTaggedToInt32WithTaggedNumber) {
   Node* value =
@@ skipping 464 matching lines @@
                       CaptureEq(&branch),
                       IsBranch(IsUint32LessThanOrEqual(
                                    value, IsInt32Constant(Smi::kMaxValue)),
                                graph()->start()))),
                   AllOf(CaptureEq(&if_false), IsIfFalse(CaptureEq(&branch))))));
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8