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

src/compiler/simplified-operator-reducer.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-reducer.h"
 
 #include "src/compiler/js-graph.h"
 #include "src/compiler/machine-operator.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/operator-properties.h"
@@ skipping 130 matching lines @@
         return Changed(node);
       }
       break;
     }
     case IrOpcode::kCheckTaggedPointer: {
       Node* const input = node->InputAt(0);
       if (DecideObjectIsSmi(input) == Decision::kFalse) {
         ReplaceWithValue(node, input);
         return Replace(input);
       }
+      NodeMatcher m(input);
+      if (m.IsCheckTaggedPointer()) {
+        ReplaceWithValue(node, input);
+        return Replace(input);
+      }
       break;
     }
     case IrOpcode::kCheckTaggedSigned: {
       Node* const input = node->InputAt(0);
       if (DecideObjectIsSmi(input) == Decision::kTrue) {
         ReplaceWithValue(node, input);
         return Replace(input);
       }
       NodeMatcher m(input);
-      if (m.IsConvertTaggedHoleToUndefined()) {
+      if (m.IsCheckTaggedSigned()) {
+        ReplaceWithValue(node, input);
+        return Replace(input);
+      } else if (m.IsConvertTaggedHoleToUndefined()) {
         node->ReplaceInput(0, m.InputAt(0));
         return Changed(node);
       }
       break;
     }
     case IrOpcode::kObjectIsSmi: {
       Node* const input = node->InputAt(0);
       switch (DecideObjectIsSmi(input)) {
         case Decision::kTrue:
           return ReplaceBoolean(true);
@@ skipping 62 matching lines @@
   return jsgraph()->isolate();
 }
 
 MachineOperatorBuilder* SimplifiedOperatorReducer::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8