[turbofan] MemoryOptimizer cannot deal with dead nodes in use lists.

src/compiler/pipeline.cc

Index: src/compiler/pipeline.cc
diff --git a/src/compiler/pipeline.cc b/src/compiler/pipeline.cc
index ff442dda9ec88a42c4bb7acdf19e6f9c40a0f88c..6022aa8e54c3de52b49db51f1967720d21029465 100644
--- a/src/compiler/pipeline.cc
+++ b/src/compiler/pipeline.cc
@@ -1032,6 +1032,13 @@ struct MemoryOptimizationPhase {
   static const char* phase_name() { return "memory optimization"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
+    // The memory optimizer requires the graphs to be trimmed, so trim now.
+    GraphTrimmer trimmer(temp_zone, data->graph());
+    NodeVector roots(temp_zone);
+    data->jsgraph()->GetCachedNodes(&roots);
+    trimmer.TrimGraph(roots.begin(), roots.end());
+
+    // Optimize allocations and load/store operations.
     MemoryOptimizer optimizer(data->jsgraph(), temp_zone);
     optimizer.Optimize();
   }