diff --git a/Source/cmSystemTools.cxx b/Source/cmSystemTools.cxx
index 635e31cd6..c27b5616c 100644
--- a/Source/cmSystemTools.cxx
+++ b/Source/cmSystemTools.cxx
@@ -1616,7 +1616,7 @@ long copy_data(struct archive *ar, struct archive *aw)
       return (r);
       }
     }
-#if !defined(__clang__)
+#if !defined(__clang__) && !defined(__HP_aCC)
   return r; /* this should not happen but it quiets some compilers */
 #endif
 }