diff --git a/llvm/lib/Support/GraphWriter.cpp b/llvm/lib/Support/GraphWriter.cpp
index 7a9400d..85be415 100644
--- a/llvm/lib/Support/GraphWriter.cpp
+++ b/llvm/lib/Support/GraphWriter.cpp
@@ -219,5 +219,8 @@
   errs() << "Running 'dotty' program... ";
   if (!ExecGraphViewer(dotty, args, Filename, wait, ErrMsg))
     return;
+#else
+  (void)Filename;
+  (void)ErrMsg;
 #endif
 }