diff --git a/Makefile.in b/Makefile.in
index 8ec594833..b4c45bde6 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -747,6 +747,7 @@ FASTCOV_OPT += BROKEN_RTN
 FASTCOV_OPT += NUM_ASSERT
 FASTCOV_OPT += SELF_CHECK
 FASTCOV_OPT += UASSERT
+FASTCOV_OPT += UDEBUGONLY
 FASTCOV_OPT += UINFO
 FASTCOV_OPT += assert
 FASTCOV_OPT += 'if (VL_UNCOVERABLE'