diff --git a/include/llvm/Target/TargetRegisterInfo.h b/include/llvm/Target/TargetRegisterInfo.h
index 82fccde8de8..958bea6f2b9 100644
--- a/include/llvm/Target/TargetRegisterInfo.h
+++ b/include/llvm/Target/TargetRegisterInfo.h
@@ -901,6 +901,7 @@ static inline raw_ostream &operator<<(raw_ostream &OS, const PrintReg &PR) {
 /// Usage: OS << PrintRegUnit(Unit, TRI) << '\n';
 ///
 class PrintRegUnit {
+protected:
   const TargetRegisterInfo *TRI;
   unsigned Unit;
 public:
@@ -914,6 +915,21 @@ static inline raw_ostream &operator<<(raw_ostream &OS, const PrintRegUnit &PR) {
   return OS;
 }
 
+/// PrintVRegOrUnit - It is often convenient to track virtual registers and
+/// physical register units in the same list.
+class PrintVRegOrUnit : protected PrintRegUnit {
+public:
+  PrintVRegOrUnit(unsigned VRegOrUnit, const TargetRegisterInfo *tri)
+    : PrintRegUnit(VRegOrUnit, tri) {}
+  void print(raw_ostream&) const;
+};
+
+static inline raw_ostream &operator<<(raw_ostream &OS,
+                                      const PrintVRegOrUnit &PR) {
+  PR.print(OS);
+  return OS;
+}
+
 } // End llvm namespace
 
 #endif
diff --git a/lib/CodeGen/TargetRegisterInfo.cpp b/lib/CodeGen/TargetRegisterInfo.cpp
index ffcee1f51dd..5a1524364b6 100644
--- a/lib/CodeGen/TargetRegisterInfo.cpp
+++ b/lib/CodeGen/TargetRegisterInfo.cpp
@@ -73,6 +73,14 @@ void PrintRegUnit::print(raw_ostream &OS) const {
     OS << '~' << TRI->getName(*Roots);
 }
 
+void PrintVRegOrUnit::print(raw_ostream &OS) const {
+  if (TRI && TRI->isVirtualRegister(Unit)) {
+    OS << "%vreg" << TargetRegisterInfo::virtReg2Index(Unit);
+    return;
+  }
+  PrintRegUnit::print(OS);
+}
+
 /// getAllocatableClass - Return the maximal subclass of the given register
 /// class that is alloctable, or NULL.
 const TargetRegisterClass *