[turbofan] Drop the obsolete TypeGuard operator.

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 157 matching lines @@
     case IrOpcode::kNumberTrunc: {
       Node* const input = NodeProperties::GetValueInput(node, 0);
       Type* const input_type = NodeProperties::GetType(input);
       if (input_type->Is(type_cache_.kIntegerOrMinusZeroOrNaN)) {
         return Replace(input);
       }
       break;
     }
     case IrOpcode::kReferenceEqual:
       return ReduceReferenceEqual(node);
-    case IrOpcode::kTypeGuard:
-      return ReduceTypeGuard(node);
     default:
       break;
   }
   return NoChange();
 }
 
 Reduction SimplifiedOperatorReducer::ReduceReferenceEqual(Node* node) {
   DCHECK_EQ(IrOpcode::kReferenceEqual, node->opcode());
   Node* const left = NodeProperties::GetValueInput(node, 0);
   Node* const right = NodeProperties::GetValueInput(node, 1);
   HeapObjectMatcher match_left(left);
   HeapObjectMatcher match_right(right);
   if (match_left.HasValue() && match_right.HasValue()) {
     if (match_left.Value().is_identical_to(match_right.Value())) {
       return Replace(jsgraph()->TrueConstant());
     } else {
       return Replace(jsgraph()->FalseConstant());
     }
   }
   return NoChange();
 }
 
-Reduction SimplifiedOperatorReducer::ReduceTypeGuard(Node* node) {
-  DCHECK_EQ(IrOpcode::kTypeGuard, node->opcode());
-  Node* const input = NodeProperties::GetValueInput(node, 0);
-  Type* const input_type = NodeProperties::GetTypeOrAny(input);
-  Type* const guard_type = TypeOf(node->op());
-  if (input_type->Is(guard_type)) return Replace(input);
-  return NoChange();
-}
-
 Reduction SimplifiedOperatorReducer::Change(Node* node, const Operator* op,
                                             Node* a) {
   DCHECK_EQ(node->InputCount(), OperatorProperties::GetTotalInputCount(op));
   DCHECK_LE(1, node->InputCount());
   node->ReplaceInput(0, a);
   NodeProperties::ChangeOp(node, op);
   return Changed(node);
 }
 
 Reduction SimplifiedOperatorReducer::ReplaceBoolean(bool value) {
@@ skipping 23 matching lines @@
 Graph* SimplifiedOperatorReducer::graph() const { return jsgraph()->graph(); }
 
 
 MachineOperatorBuilder* SimplifiedOperatorReducer::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8