diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -2499,7 +2499,8 @@
 			goto dropafterack;
 		}
 		if (tcp_is_sack_recovery(tp, &to)) {
-			if (((sack_changed = tcp_sack_doack(tp, &to, th->th_ack)) != 0) &&
+			sack_changed = tcp_sack_doack(tp, &to, th->th_ack);
+			if ((sack_changed != SACK_NOCHANGE) &&
 			    (tp->t_flags & TF_LRD)) {
 				tcp_sack_lost_retransmission(tp, th);
 			}