[turbofan] Nodes are killed by resetting all their inputs to zero.

src/compiler/value-numbering-reducer.cc

Index: src/compiler/value-numbering-reducer.cc
diff --git a/src/compiler/value-numbering-reducer.cc b/src/compiler/value-numbering-reducer.cc
index bdc9a520174a0c3d89d8123ec819fe8c5580c4d2..595a4f30171904aa33fd3b6b3d19cf88816a335e 100644
--- a/src/compiler/value-numbering-reducer.cc
+++ b/src/compiler/value-numbering-reducer.cc
@@ -59,7 +59,7 @@ ValueNumberingReducer::~ValueNumberingReducer() {}
 Reduction ValueNumberingReducer::Reduce(Node* node) {
   Entry** head = &buckets_[HashCode(node) % arraysize(buckets_)];
   for (Entry* entry = *head; entry; entry = entry->next()) {
-    if (entry->node()->op() == NULL) continue;
+    if (entry->node()->IsDead()) continue;
     if (entry->node() == node) return NoChange();
     if (Equals(node, entry->node())) {
       return Replace(entry->node());