diff --git a/include/llvm/CodeGen/MachineInstrBuilder.h b/include/llvm/CodeGen/MachineInstrBuilder.h
index 1dcdf086c85..d33e0aa2ab2 100644
--- a/include/llvm/CodeGen/MachineInstrBuilder.h
+++ b/include/llvm/CodeGen/MachineInstrBuilder.h
@@ -82,7 +82,7 @@ public:
   /// Get the register for the operand index.
   /// The operand at the index should be a register (asserted by
   /// MachineOperand).
-  unsigned getReg(unsigned Idx) { return MI->getOperand(Idx).getReg(); }
+  unsigned getReg(unsigned Idx) const { return MI->getOperand(Idx).getReg(); }
 
   /// Add a new virtual register operand.
   const MachineInstrBuilder &addReg(unsigned RegNo, unsigned flags = 0,