diff --git a/include/llvm/CodeGen/MachineFunction.h b/include/llvm/CodeGen/MachineFunction.h
index d9afd8d65f4..4810742b073 100644
--- a/include/llvm/CodeGen/MachineFunction.h
+++ b/include/llvm/CodeGen/MachineFunction.h
@@ -108,7 +108,10 @@ class MachineFunction : private Annotation {
   /// LiveIns/LiveOuts - Keep track of the physical registers that are
   /// livein/liveout of the function.  Live in values are typically arguments in
   /// registers, live out values are typically return values in registers.
-  std::vector<unsigned> LiveIns, LiveOuts;
+  /// LiveIn values are allowed to have virtual registers associated with them,
+  /// stored in the second element.
+  std::vector<std::pair<unsigned, unsigned> > LiveIns;
+  std::vector<unsigned> LiveOuts;
 
 public:
   MachineFunction(const Function *Fn, const TargetMachine &TM);
@@ -177,16 +180,20 @@ public:
 
   /// addLiveIn/Out - Add the specified register as a live in/out.  Note that it
   /// is an error to add the same register to the same set more than once.
-  void addLiveIn(unsigned Reg) { LiveIns.push_back(Reg); }
+  void addLiveIn(unsigned Reg, unsigned vreg = 0) {
+    LiveIns.push_back(std::make_pair(Reg, vreg));
+  }
   void addLiveOut(unsigned Reg) { LiveOuts.push_back(Reg); }
 
   // Iteration support for live in/out sets.  These sets are kept in sorted
   // order by their register number.
-  typedef std::vector<unsigned>::const_iterator liveinout_iterator;
-  liveinout_iterator livein_begin() const { return LiveIns.begin(); }
-  liveinout_iterator livein_end()   const { return LiveIns.end(); }
-  liveinout_iterator liveout_begin() const { return LiveOuts.begin(); }
-  liveinout_iterator liveout_end()   const { return LiveOuts.end(); }
+  typedef std::vector<std::pair<unsigned,unsigned> >::const_iterator
+  livein_iterator;
+  typedef std::vector<unsigned>::const_iterator liveout_iterator;
+  livein_iterator livein_begin() const { return LiveIns.begin(); }
+  livein_iterator livein_end()   const { return LiveIns.end(); }
+  liveout_iterator liveout_begin() const { return LiveOuts.begin(); }
+  liveout_iterator liveout_end()   const { return LiveOuts.end(); }
 
   /// getBlockNumbered - MachineBasicBlocks are automatically numbered when they
   /// are inserted into the machine function.  The block number for a machine
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 405d9ec6504..d75bf3fb0ef 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -95,7 +95,7 @@ bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
   // beginning of the function that we will pretend "defines" the values.  This
   // is to make the interval analysis simpler by providing a number.
   if (fn.livein_begin() != fn.livein_end()) {
-    unsigned FirstLiveIn = *fn.livein_begin();
+    unsigned FirstLiveIn = fn.livein_begin()->first;
 
     // Find a reg class that contains this live in.
     const TargetRegisterClass *RC = 0;
@@ -128,11 +128,11 @@ bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
   // Note intervals due to live-in values.
   if (fn.livein_begin() != fn.livein_end()) {
     MachineBasicBlock *Entry = fn.begin();
-    for (MachineFunction::liveinout_iterator I = fn.livein_begin(),
+    for (MachineFunction::livein_iterator I = fn.livein_begin(),
            E = fn.livein_end(); I != E; ++I) {
       handlePhysicalRegisterDef(Entry, Entry->begin(),
-                                getOrCreateInterval(*I), 0, 0);
-      for (const unsigned* AS = mri_->getAliasSet(*I); *AS; ++AS)
+                                getOrCreateInterval(I->first), 0, 0);
+      for (const unsigned* AS = mri_->getAliasSet(I->first); *AS; ++AS)
         handlePhysicalRegisterDef(Entry, Entry->begin(),
                                   getOrCreateInterval(*AS), 0, 0);
     }
diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp
index 94380ff542d..c11e00f0c8d 100644
--- a/lib/CodeGen/LiveVariables.cpp
+++ b/lib/CodeGen/LiveVariables.cpp
@@ -165,11 +165,11 @@ bool LiveVariables::runOnMachineFunction(MachineFunction &MF) {
   VirtRegInfo.resize(64);
 
   // Mark live-in registers as live-in.
-  for (MachineFunction::liveinout_iterator I = MF.livein_begin(),
+  for (MachineFunction::livein_iterator I = MF.livein_begin(),
          E = MF.livein_end(); I != E; ++I) {
-    assert(MRegisterInfo::isPhysicalRegister(*I) &&
+    assert(MRegisterInfo::isPhysicalRegister(I->first) &&
            "Cannot have a live-in virtual register!");
-    HandlePhysRegDef(*I, 0);
+    HandlePhysRegDef(I->first, 0);
   }
 
   // Calculate live variable information in depth first order on the CFG of the
@@ -272,7 +272,7 @@ bool LiveVariables::runOnMachineFunction(MachineFunction &MF) {
     // it as using all of the live-out values in the function.
     if (!MBB->empty() && TII.isReturn(MBB->back().getOpcode())) {
       MachineInstr *Ret = &MBB->back();
-      for (MachineFunction::liveinout_iterator I = MF.liveout_begin(),
+      for (MachineFunction::liveout_iterator I = MF.liveout_begin(),
              E = MF.liveout_end(); I != E; ++I) {
         assert(MRegisterInfo::isPhysicalRegister(*I) &&
                "Cannot have a live-in virtual register!");