diff --git a/include/llvm/CodeGen/SelectionDAGNodes.h b/include/llvm/CodeGen/SelectionDAGNodes.h
index d4aa78211f7..7b8c1dcfb83 100644
--- a/include/llvm/CodeGen/SelectionDAGNodes.h
+++ b/include/llvm/CodeGen/SelectionDAGNodes.h
@@ -1572,6 +1572,8 @@ namespace ISD {
   struct OutputArg {
     ArgFlagsTy Flags;
     SDValue Val;
+
+    /// IsFixed - Is this a "fixed" value, ie not passed through a vararg "...".
     bool IsFixed;
 
     OutputArg() : IsFixed(false) {}