[turbofan] Strength reduce CheckTaggedSigned/Pointer with checked inputs.

test/unittests/compiler/simplified-operator-reducer-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/compiler/simplified-operator.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/simplified-operator-reducer.h"
 #include "src/compiler/types.h"
@@ skipping 360 matching lines @@
       factory()->species_symbol(), factory()->undefined_value()};
   TRACED_FOREACH(Handle<HeapObject>, object, kHeapObjects) {
     Node* value = HeapConstant(object);
     Reduction reduction = Reduce(graph()->NewNode(
         simplified()->CheckTaggedPointer(), value, effect, control));
     ASSERT_TRUE(reduction.Changed());
     EXPECT_EQ(value, reduction.replacement());
   }
 }
 
+TEST_F(SimplifiedOperatorReducerTest,
+       CheckTaggedPointerWithCheckTaggedPointer) {
+  Node* param0 = Parameter(0);
+  Node* effect = graph()->start();
+  Node* control = graph()->start();
+  Node* value = effect = graph()->NewNode(simplified()->CheckTaggedPointer(),
+                                          param0, effect, control);
+  Reduction reduction = Reduce(graph()->NewNode(
+      simplified()->CheckTaggedPointer(), value, effect, control));
+  ASSERT_TRUE(reduction.Changed());
+  EXPECT_EQ(value, reduction.replacement());
+}
+
 // -----------------------------------------------------------------------------
 // CheckTaggedSigned
 
 TEST_F(SimplifiedOperatorReducerTest,
        CheckTaggedSignedWithChangeInt31ToTaggedSigned) {
   Node* param0 = Parameter(0);
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* value =
       graph()->NewNode(simplified()->ChangeInt31ToTaggedSigned(), param0);
   Reduction reduction = Reduce(graph()->NewNode(
       simplified()->CheckTaggedSigned(), value, effect, control));
   ASSERT_TRUE(reduction.Changed());
   EXPECT_EQ(value, reduction.replacement());
 }
 
 TEST_F(SimplifiedOperatorReducerTest, CheckTaggedSignedWithNumberConstant) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* value = NumberConstant(1.0);
   Reduction reduction = Reduce(graph()->NewNode(
       simplified()->CheckTaggedSigned(), value, effect, control));
   ASSERT_TRUE(reduction.Changed());
   EXPECT_EQ(value, reduction.replacement());
 }
 
+TEST_F(SimplifiedOperatorReducerTest, CheckTaggedSignedWithCheckTaggedSigned) {
+  Node* param0 = Parameter(0);
+  Node* effect = graph()->start();
+  Node* control = graph()->start();
+  Node* value = effect = graph()->NewNode(simplified()->CheckTaggedSigned(),
+                                          param0, effect, control);
+  Reduction reduction = Reduce(graph()->NewNode(
+      simplified()->CheckTaggedSigned(), value, effect, control));
+  ASSERT_TRUE(reduction.Changed());
+  EXPECT_EQ(value, reduction.replacement());
+}
+
 // -----------------------------------------------------------------------------
 // NumberAbs
 
 TEST_F(SimplifiedOperatorReducerTest, NumberAbsWithNumberConstant) {
   TRACED_FOREACH(double, n, kFloat64Values) {
     Reduction reduction =
         Reduce(graph()->NewNode(simplified()->NumberAbs(), NumberConstant(n)));
     ASSERT_TRUE(reduction.Changed());
     EXPECT_THAT(reduction.replacement(), IsNumberConstant(std::fabs(n)));
   }
@@ skipping 38 matching lines @@
     Reduction reduction = Reduce(
         graph()->NewNode(simplified()->ObjectIsSmi(), NumberConstant(n)));
     ASSERT_TRUE(reduction.Changed());
     EXPECT_THAT(reduction.replacement(), IsBooleanConstant(IsSmiDouble(n)));
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8