diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp
index facf0c1..b44df47 100644
--- a/lib/CodeGen/VirtRegMap.cpp
+++ b/lib/CodeGen/VirtRegMap.cpp
@@ -74,8 +74,7 @@
   EmergencySpillSlots.clear();
   
   SpillSlotToUsesMap.resize(8);
-  ImplicitDefed.resize(MF->getRegInfo().getLastVirtReg()+1-
-                       TargetRegisterInfo::FirstVirtualRegister);
+  ImplicitDefed.resize(MF->getRegInfo().getNumVirtRegs());
 
   allocatableRCRegs.clear();
   for (TargetRegisterInfo::regclass_iterator I = TRI->regclass_begin(),
@@ -96,7 +95,7 @@
   Virt2SplitMap.grow(LastVirtReg);
   Virt2SplitKillMap.grow(LastVirtReg);
   ReMatMap.grow(LastVirtReg);
-  ImplicitDefed.resize(LastVirtReg-TargetRegisterInfo::FirstVirtualRegister+1);
+  ImplicitDefed.resize(MF->getRegInfo().getNumVirtRegs());
 }
 
 unsigned VirtRegMap::createSpillSlot(const TargetRegisterClass *RC) {
@@ -229,10 +228,11 @@
   UnusedRegs.resize(NumRegs);
 
   BitVector Used(NumRegs);
-  for (unsigned i = TargetRegisterInfo::FirstVirtualRegister,
-         e = MF->getRegInfo().getLastVirtReg(); i <= e; ++i)
-    if (Virt2PhysMap[i] != (unsigned)VirtRegMap::NO_PHYS_REG)
-      Used.set(Virt2PhysMap[i]);
+  for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
+    unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
+    if (Virt2PhysMap[Reg] != (unsigned)VirtRegMap::NO_PHYS_REG)
+      Used.set(Virt2PhysMap[Reg]);
+  }
 
   BitVector Allocatable = TRI->getAllocatableSet(*MF);
   bool AnyUnused = false;
@@ -260,18 +260,26 @@
   const MachineRegisterInfo &MRI = MF->getRegInfo();
 
   OS << "********** REGISTER MAP **********\n";
-  for (unsigned i = TargetRegisterInfo::FirstVirtualRegister,
-         e = MF->getRegInfo().getLastVirtReg(); i <= e; ++i) {
-    if (Virt2PhysMap[i] != (unsigned)VirtRegMap::NO_PHYS_REG)
-      OS << "[reg" << i << " -> " << TRI->getName(Virt2PhysMap[i])
-         << "] " << MRI.getRegClass(i)->getName() << "\n";
+  for (unsigned i = 0, e = MRI.getNumVirtRegs(); i != e; ++i) {
+    unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
+    if (Virt2PhysMap[Reg] != (unsigned)VirtRegMap::NO_PHYS_REG) {
+      OS << '[';
+      TRI->printReg(Reg, OS);
+      OS << " -> ";
+      TRI->printReg(Virt2PhysMap[Reg], OS);
+      OS << "] " << MRI.getRegClass(i)->getName() << "\n";
+    }
   }
 
-  for (unsigned i = TargetRegisterInfo::FirstVirtualRegister,
-         e = MF->getRegInfo().getLastVirtReg(); i <= e; ++i)
-    if (Virt2StackSlotMap[i] != VirtRegMap::NO_STACK_SLOT)
-      OS << "[reg" << i << " -> fi#" << Virt2StackSlotMap[i]
-         << "] " << MRI.getRegClass(i)->getName() << "\n";
+  for (unsigned i = 0, e = MRI.getNumVirtRegs(); i != e; ++i) {
+    unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
+    if (Virt2StackSlotMap[Reg] != VirtRegMap::NO_STACK_SLOT) {
+      OS << '[';
+      TRI->printReg(Reg, OS);
+      OS << " -> fi#" << Virt2StackSlotMap[Reg]
+         << "] " << MRI.getRegClass(Reg)->getName() << "\n";
+    }
+  }
   OS << '\n';
 }
 
diff --git a/lib/CodeGen/VirtRegMap.h b/lib/CodeGen/VirtRegMap.h
index 2fe27ce..180b43b 100644
--- a/lib/CodeGen/VirtRegMap.h
+++ b/lib/CodeGen/VirtRegMap.h
@@ -432,12 +432,12 @@
 
     /// @brief Mark the specified register as being implicitly defined.
     void setIsImplicitlyDefined(unsigned VirtReg) {
-      ImplicitDefed.set(VirtReg-TargetRegisterInfo::FirstVirtualRegister);
+      ImplicitDefed.set(TargetRegisterInfo::virtReg2Index(VirtReg));
     }
 
     /// @brief Returns true if the virtual register is implicitly defined.
     bool isImplicitlyDefined(unsigned VirtReg) const {
-      return ImplicitDefed[VirtReg-TargetRegisterInfo::FirstVirtualRegister];
+      return ImplicitDefed[TargetRegisterInfo::virtReg2Index(VirtReg)];
     }
 
     /// @brief Updates information about the specified virtual register's value