[turbofan] Drop the obsolete TypeGuard operator.

src/compiler/effect-control-linearizer.cc

 // Copyright 2015 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/effect-control-linearizer.h"
 
 #include "src/code-factory.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/linkage.h"
@@ skipping 377 matching lines @@
     }
   }
 }
 
 bool EffectControlLinearizer::TryWireInStateEffect(Node* node,
                                                    Node* frame_state,
                                                    Node** effect,
                                                    Node** control) {
   ValueEffectControl state(nullptr, nullptr, nullptr);
   switch (node->opcode()) {
-    case IrOpcode::kTypeGuard:
-      state = LowerTypeGuard(node, *effect, *control);
-      break;
     case IrOpcode::kChangeBitToTagged:
       state = LowerChangeBitToTagged(node, *effect, *control);
       break;
     case IrOpcode::kChangeInt31ToTaggedSigned:
       state = LowerChangeInt31ToTaggedSigned(node, *effect, *control);
       break;
     case IrOpcode::kChangeInt32ToTagged:
       state = LowerChangeInt32ToTagged(node, *effect, *control);
       break;
     case IrOpcode::kChangeUint32ToTagged:
@@ skipping 92 matching lines @@
     default:
       return false;
   }
   NodeProperties::ReplaceUses(node, state.value, state.effect, state.control);
   *effect = state.effect;
   *control = state.control;
   return true;
 }
 
 EffectControlLinearizer::ValueEffectControl
-EffectControlLinearizer::LowerTypeGuard(Node* node, Node* effect,
-                                        Node* control) {
-  Node* value = node->InputAt(0);
-  return ValueEffectControl(value, effect, control);
-}
-
-EffectControlLinearizer::ValueEffectControl
 EffectControlLinearizer::LowerChangeFloat64ToTagged(Node* node, Node* effect,
                                                     Node* control) {
   Node* value = node->InputAt(0);
 
   Node* value32 = graph()->NewNode(machine()->RoundFloat64ToInt32(), value);
   Node* check_same = graph()->NewNode(
       machine()->Float64Equal(), value,
       graph()->NewNode(machine()->ChangeInt32ToFloat64(), value32));
   Node* branch_same = graph()->NewNode(common()->Branch(), check_same, control);
 
@@ skipping 1167 matching lines @@
         isolate(), graph()->zone(), callable.descriptor(), 0, flags,
         Operator::kNoThrow);
     to_number_operator_.set(common()->Call(desc));
   }
   return to_number_operator_.get();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8