3 files changed, 18 insertions, 7 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index fcc8b96578f..567c42c77cb 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1331,8 +1331,6 @@ void DAGCombiner::Run(CombineLevel AtLevel) {
     DEBUG(dbgs() << " ... into: ";
           RV.getNode()->dump(&DAG));
 
-    // Transfer debug value.
-    DAG.TransferDbgValues(SDValue(N, 0), RV);
     if (N->getNumValues() == RV.getNode()->getNumValues())
       DAG.ReplaceAllUsesWith(N, RV.getNode());
     else {
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 4c6ae245f5a..08bc871dfe4 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -179,8 +179,6 @@ public:
            "Replacing one node with another that produces a different number "
            "of values!");
     DAG.ReplaceAllUsesWith(Old, New);
-    for (unsigned i = 0, e = Old->getNumValues(); i != e; ++i)
-      DAG.TransferDbgValues(SDValue(Old, i), SDValue(New, i));
     if (UpdatedNodes)
       UpdatedNodes->insert(New);
     ReplacedNode(Old);
@@ -190,7 +188,6 @@ public:
           dbgs() << "     with:      "; New->dump(&DAG));
 
     DAG.ReplaceAllUsesWith(Old, New);
-    DAG.TransferDbgValues(Old, New);
     if (UpdatedNodes)
       UpdatedNodes->insert(New.getNode());
     ReplacedNode(Old.getNode());
@@ -203,7 +200,6 @@ public:
       DEBUG(dbgs() << (i == 0 ? "     with:      "
                               : "      and:      ");
             New[i]->dump(&DAG));
-      DAG.TransferDbgValues(SDValue(Old, i), New[i]);
       if (UpdatedNodes)
         UpdatedNodes->insert(New[i].getNode());
     }
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 9e6f1158156..be19877e408 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -6333,6 +6333,9 @@ void SelectionDAG::ReplaceAllUsesWith(SDValue FromN, SDValue To) {
     AddModifiedNodeToCSEMaps(User);
   }
 
+  // Preserve Debug Values
+  TransferDbgValues(FromN, To);
+
   // If we just RAUW'd the root, take note.
   if (FromN == getRoot())
     setRoot(To);
@@ -6356,6 +6359,11 @@ void SelectionDAG::ReplaceAllUsesWith(SDNode *From, SDNode *To) {
   if (From == To)
     return;
 
+  // Preserve Debug Info. Only do this if there's a use.
+  for (unsigned i = 0, e = From->getNumValues(); i != e; ++i)
+    if (From->hasAnyUseOfValue(i))
+      TransferDbgValues(SDValue(From, i), SDValue(To, i));
+
   // Iterate over just the existing users of From. See the comments in
   // the ReplaceAllUsesWith above.
   SDNode::use_iterator UI = From->use_begin(), UE = From->use_end();
@@ -6395,6 +6403,10 @@ void SelectionDAG::ReplaceAllUsesWith(SDNode *From, const SDValue *To) {
   if (From->getNumValues() == 1)  // Handle the simple case efficiently.
     return ReplaceAllUsesWith(SDValue(From, 0), To[0]);
 
+  // Preserve Debug Info.
+  for (unsigned i = 0, e = From->getNumValues(); i != e; ++i)
+    TransferDbgValues(SDValue(From, i), *To);
+
   // Iterate over just the existing users of From. See the comments in
   // the ReplaceAllUsesWith above.
   SDNode::use_iterator UI = From->use_begin(), UE = From->use_end();
@@ -6439,6 +6451,9 @@ void SelectionDAG::ReplaceAllUsesOfValueWith(SDValue From, SDValue To){
     return;
   }
 
+  // Preserve Debug Info.
+  TransferDbgValues(From, To);
+
   // Iterate over just the existing users of From. See the comments in
   // the ReplaceAllUsesWith above.
   SDNode::use_iterator UI = From.getNode()->use_begin(),
@@ -6513,6 +6528,8 @@ void SelectionDAG::ReplaceAllUsesOfValuesWith(const SDValue *From,
   if (Num == 1)
     return ReplaceAllUsesOfValueWith(*From, *To);
 
+  TransferDbgValues(*From, *To);
+
   // Read up all the uses and make records of them. This helps
   // processing new uses that are introduced during the
   // replacement process.
@@ -6661,7 +6678,7 @@ void SelectionDAG::AddDbgValue(SDDbgValue *DB, SDNode *SD, bool isParameter) {
   DbgInfo->add(DB, SD, isParameter);
 }
 
-/// TransferDbgValues - Transfer SDDbgValues.
+/// TransferDbgValues - Transfer SDDbgValues. Called in replace nodes.
 void SelectionDAG::TransferDbgValues(SDValue From, SDValue To) {
   if (From == To || !From.getNode()->getHasDebugValue())
     return;