diff --git a/lib/MC/MCObjectStreamer.cpp b/lib/MC/MCObjectStreamer.cpp
index b6c7341469d..0d2ce83a8a1 100644
--- a/lib/MC/MCObjectStreamer.cpp
+++ b/lib/MC/MCObjectStreamer.cpp
@@ -226,8 +226,10 @@ void MCObjectStreamer::EmitInstToFragment(const MCInst &Inst) {
   IF->getContents().append(Code.begin(), Code.end());
 }
 
+#ifndef NDEBUG
 static const char *BundlingNotImplementedMsg =
   "Aligned bundling is not implemented for this object format";
+#endif
 
 void MCObjectStreamer::EmitBundleAlignMode(unsigned AlignPow2) {
   llvm_unreachable(BundlingNotImplementedMsg);