diff --git a/llvm/include/llvm/Target/TargetRegisterInfo.h b/llvm/include/llvm/Target/TargetRegisterInfo.h
index 205e76f9c6fc..afa395f3d733 100644
--- a/llvm/include/llvm/Target/TargetRegisterInfo.h
+++ b/llvm/include/llvm/Target/TargetRegisterInfo.h
@@ -351,13 +351,13 @@ public:
   /// The first virtual register in a function will get the index 0.
   static unsigned virtReg2Index(unsigned Reg) {
     assert(isVirtualRegister(Reg) && "Not a virtual register");
-    return Reg - (1u << 31);
+    return Reg & ~(1u << 31);
   }
 
   /// index2VirtReg - Convert a 0-based index to a virtual register number.
   /// This is the inverse operation of VirtReg2IndexFunctor below.
   static unsigned index2VirtReg(unsigned Index) {
-    return Index + (1u << 31);
+    return Index | (1u << 31);
   }
 
   /// getMinimalPhysRegClass - Returns the Register Class of a physical