diff --git a/utils/TableGen/AsmWriterInst.h b/utils/TableGen/AsmWriterInst.h
index 7d88e5a9d03..a59112efea4 100644
--- a/utils/TableGen/AsmWriterInst.h
+++ b/utils/TableGen/AsmWriterInst.h
@@ -36,7 +36,7 @@ namespace llvm {
 
     /// MiOpNo - For isMachineInstrOperand, this is the operand number of the
     /// machine instruction.
-    unsigned MIOpNo;
+    unsigned MIOpNo = 0;
 
     /// Str - For isLiteralTextOperand, this IS the literal text.  For
     /// isMachineInstrOperand, this is the PrinterMethodName for the operand..