Index: include/llvm/CodeGen/MachineRegisterInfo.h
===================================================================
--- include/llvm/CodeGen/MachineRegisterInfo.h
+++ include/llvm/CodeGen/MachineRegisterInfo.h
@@ -760,6 +760,13 @@
     UsedPhysRegMask.setBitsNotInMask(RegMask);
   }
 
+  /// Mark \p Reg and any aliases of it as used.
+  void addPhysRegUsed(const TargetRegisterInfo &TRI, unsigned Reg) {
+    MCRegAliasIterator R(Reg, &TRI, true);
+    for (; R.isValid(); ++R)
+      UsedPhysRegMask.set(*R);
+  }
+
   const BitVector &getUsedPhysRegsMask() const { return UsedPhysRegMask; }
 
   //===--------------------------------------------------------------------===//