[turbofan] Make Node::set_op safer via wrapper.

src/compiler/diamond.h

 // Copyright 2013 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.
 
 #ifndef V8_COMPILER_DIAMOND_H_
 #define V8_COMPILER_DIAMOND_H_
 
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
 #include "src/compiler/node.h"
+#include "src/compiler/node-properties.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 // A helper to make it easier to build diamond-shaped control patterns.
 struct Diamond {
   Graph* graph;
   CommonOperatorBuilder* common;
   Node* branch;
@@ skipping 32 matching lines @@
     return graph->NewNode(common->Phi(machine_type, 2), tv, fv, merge);
   }
 
   Node* EffectPhi(Node* tv, Node* fv) {
     return graph->NewNode(common->EffectPhi(2), tv, fv, merge);
   }
 
   void OverwriteWithPhi(Node* node, MachineType machine_type, Node* tv,
                         Node* fv) {
     DCHECK(node->InputCount() >= 3);
-    node->set_op(common->Phi(machine_type, 2));
     node->ReplaceInput(0, tv);
     node->ReplaceInput(1, fv);
     node->ReplaceInput(2, merge);
     node->TrimInputCount(3);
+    NodeProperties::ChangeOp(node, common->Phi(machine_type, 2));
   }
 
   void OverwriteWithEffectPhi(Node* node, Node* te, Node* fe) {
     DCHECK(node->InputCount() >= 3);
-    node->set_op(common->EffectPhi(2));
     node->ReplaceInput(0, te);
     node->ReplaceInput(1, fe);
     node->ReplaceInput(2, merge);
     node->TrimInputCount(3);
+    NodeProperties::ChangeOp(node, common->EffectPhi(2));
   }
 };
 }
 }
 }  // namespace v8::internal::compiler
 
 #endif  // V8_COMPILER_DIAMOND_H_