diff --git a/llvm/include/llvm/CodeGen/RDFGraph.h b/llvm/include/llvm/CodeGen/RDFGraph.h
index e0205d7c92c88..a323ee9dc396d 100644
--- a/llvm/include/llvm/CodeGen/RDFGraph.h
+++ b/llvm/include/llvm/CodeGen/RDFGraph.h
@@ -749,7 +749,6 @@ namespace rdf {
 
     RegisterRef makeRegRef(unsigned Reg, unsigned Sub) const;
     RegisterRef makeRegRef(const MachineOperand &Op) const;
-    RegisterRef restrictRef(RegisterRef AR, RegisterRef BR) const;
 
     NodeAddr<RefNode*> getNextRelated(NodeAddr<InstrNode*> IA,
         NodeAddr<RefNode*> RA) const;
diff --git a/llvm/lib/CodeGen/RDFGraph.cpp b/llvm/lib/CodeGen/RDFGraph.cpp
index 05c1e16b7dfe9..ec383b9b1c651 100644
--- a/llvm/lib/CodeGen/RDFGraph.cpp
+++ b/llvm/lib/CodeGen/RDFGraph.cpp
@@ -977,18 +977,6 @@ RegisterRef DataFlowGraph::makeRegRef(const MachineOperand &Op) const {
   return RegisterRef(PRI.getRegMaskId(Op.getRegMask()), LaneBitmask::getAll());
 }
 
-RegisterRef DataFlowGraph::restrictRef(RegisterRef AR, RegisterRef BR) const {
-  if (AR.Reg == BR.Reg) {
-    LaneBitmask M = AR.Mask & BR.Mask;
-    return M.any() ? RegisterRef(AR.Reg, M) : RegisterRef();
-  }
-  // This isn't strictly correct, because the overlap may happen in the
-  // part masked out.
-  if (PRI.alias(AR, BR))
-    return AR;
-  return RegisterRef();
-}
-
 // For each stack in the map DefM, push the delimiter for block B on it.
 void DataFlowGraph::markBlock(NodeId B, DefStackMap &DefM) {
   // Push block delimiters.