3 files changed, 19 insertions, 0 deletions
diff --git a/llvm/include/llvm/CodeGen/SelectionDAG.h b/llvm/include/llvm/CodeGen/SelectionDAG.h
index 44eaff5d096..aac3e0f0c66 100644
--- a/llvm/include/llvm/CodeGen/SelectionDAG.h
+++ b/llvm/include/llvm/CodeGen/SelectionDAG.h
@@ -297,6 +297,9 @@ public:
 
     /// The node N that was updated.
     virtual void NodeUpdated(SDNode *N);
+
+    /// The node N that was inserted.
+    virtual void NodeInserted(SDNode *N);
   };
 
   struct DAGNodeDeletedListener : public DAGUpdateListener {
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 5dad16f43e0..ec8949071e8 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -647,6 +647,17 @@ public:
   }
 };
 
+class WorklistInserter : public SelectionDAG::DAGUpdateListener {
+  DAGCombiner &DC;
+
+public:
+  explicit WorklistInserter(DAGCombiner &dc)
+      : SelectionDAG::DAGUpdateListener(dc.getDAG()), DC(dc) {}
+
+  // This should eventually be pruning.
+  void NodeInserted(SDNode *N) override { }
+};
+
 } // end anonymous namespace
 
 //===----------------------------------------------------------------------===//
@@ -1399,6 +1410,8 @@ void DAGCombiner::Run(CombineLevel AtLevel) {
   LegalOperations = Level >= AfterLegalizeVectorOps;
   LegalTypes = Level >= AfterLegalizeTypes;
 
+  WorklistInserter AddNodes(*this);
+
   // Add all the dag nodes to the worklist.
   for (SDNode &Node : DAG.allnodes())
     AddToWorklist(&Node);
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 3cd08271f26..0ee308b9944 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -85,6 +85,7 @@ static SDVTList makeVTList(const EVT *VTs, unsigned NumVTs) {
 // Default null implementations of the callbacks.
 void SelectionDAG::DAGUpdateListener::NodeDeleted(SDNode*, SDNode*) {}
 void SelectionDAG::DAGUpdateListener::NodeUpdated(SDNode*) {}
+void SelectionDAG::DAGUpdateListener::NodeInserted(SDNode *) {}
 
 void SelectionDAG::DAGNodeDeletedListener::anchor() {}
 
@@ -840,6 +841,8 @@ void SelectionDAG::InsertNode(SDNode *N) {
   N->PersistentId = NextPersistentId++;
   VerifySDNode(N);
 #endif
+  for (DAGUpdateListener *DUL = UpdateListeners; DUL; DUL = DUL->Next)
+    DUL->NodeInserted(N);
 }
 
 /// RemoveNodeFromCSEMaps - Take the specified node out of the CSE map that