diff --git a/llvm/lib/CodeGen/MachineStableHash.cpp b/llvm/lib/CodeGen/MachineStableHash.cpp
--- a/llvm/lib/CodeGen/MachineStableHash.cpp
+++ b/llvm/lib/CodeGen/MachineStableHash.cpp
@@ -120,7 +120,7 @@
 
   case MachineOperand::MO_RegisterMask:
   case MachineOperand::MO_RegisterLiveOut:
-    return hash_combine(MO.getType(), MO.getTargetFlags(), MO.getRegMask());
+    return hash_combine(MO.getType(), MO.getTargetFlags(), *MO.getRegMask());
 
   case MachineOperand::MO_ShuffleMask: {
     std::vector<llvm::stable_hash> ShuffleMaskHashes;