diff --git a/llvm/lib/CodeGen/MachineBlockPlacement.cpp b/llvm/lib/CodeGen/MachineBlockPlacement.cpp
index 89ca641..40e3840 100644
--- a/llvm/lib/CodeGen/MachineBlockPlacement.cpp
+++ b/llvm/lib/CodeGen/MachineBlockPlacement.cpp
@@ -1597,7 +1597,9 @@
                    << getBlockName(BB) << " -> " << getBlockName(NextBB)
                    << "\n");
       Chain->merge(NextBB, nullptr);
+#ifndef NDEBUG
       BlocksWithUnanalyzableExits.insert(&*BB);
+#endif
       FI = NextFI;
       BB = NextBB;
     }