diff --git a/llvm/include/llvm/CodeGen/TailDuplicator.h b/llvm/include/llvm/CodeGen/TailDuplicator.h
--- a/llvm/include/llvm/CodeGen/TailDuplicator.h
+++ b/llvm/include/llvm/CodeGen/TailDuplicator.h
@@ -115,8 +115,7 @@
   bool canCompletelyDuplicateBB(MachineBasicBlock &BB);
   bool duplicateSimpleBB(MachineBasicBlock *TailBB,
                          SmallVectorImpl<MachineBasicBlock *> &TDBBs,
-                         const DenseSet<Register> &RegsUsedByPhi,
-                         SmallVectorImpl<MachineInstr *> &Copies);
+                         const DenseSet<Register> &RegsUsedByPhi);
   bool tailDuplicate(bool IsSimple,
                      MachineBasicBlock *TailBB,
                      MachineBasicBlock *ForcedLayoutPred,
diff --git a/llvm/lib/CodeGen/TailDuplicator.cpp b/llvm/lib/CodeGen/TailDuplicator.cpp
--- a/llvm/lib/CodeGen/TailDuplicator.cpp
+++ b/llvm/lib/CodeGen/TailDuplicator.cpp
@@ -716,8 +716,7 @@
 
 bool TailDuplicator::duplicateSimpleBB(
     MachineBasicBlock *TailBB, SmallVectorImpl<MachineBasicBlock *> &TDBBs,
-    const DenseSet<Register> &UsedByPhi,
-    SmallVectorImpl<MachineInstr *> &Copies) {
+    const DenseSet<Register> &UsedByPhi) {
   SmallPtrSet<MachineBasicBlock *, 8> Succs(TailBB->succ_begin(),
                                             TailBB->succ_end());
   SmallVector<MachineBasicBlock *, 8> Preds(TailBB->predecessors());
@@ -826,7 +825,7 @@
   getRegsUsedByPHIs(*TailBB, &UsedByPhi);
 
   if (IsSimple)
-    return duplicateSimpleBB(TailBB, TDBBs, UsedByPhi, Copies);
+    return duplicateSimpleBB(TailBB, TDBBs, UsedByPhi);
 
   // Iterate through all the unique predecessors and tail-duplicate this
   // block into them, if possible. Copying the list ahead of time also