+ /// getOriginal - Return the original virtual register that VirtReg descends
+ /// from through splitting.
+ /// A register that was not created by splitting is its own original.
+ /// This operation is idempotent.
+ unsigned getOriginal(unsigned VirtReg) const {
+ unsigned Orig = getPreSplitReg(VirtReg);
+ return Orig ? Orig : VirtReg;
+ }
+