diff --git a/sys/dev/sfxge/sfxge_ev.c b/sys/dev/sfxge/sfxge_ev.c
index 70e44a1e9723..da04cb3ce061 100644
--- a/sys/dev/sfxge/sfxge_ev.c
+++ b/sys/dev/sfxge/sfxge_ev.c
@@ -814,7 +814,7 @@ sfxge_ev_qstart(struct sfxge_softc *sc, unsigned int index)
 void
 sfxge_ev_stop(struct sfxge_softc *sc)
 {
-	struct sfxge_intr *intr;
+	struct sfxge_intr *intr __diagused;
 	efx_nic_t *enp;
 	int index;
 
@@ -836,7 +836,7 @@ sfxge_ev_stop(struct sfxge_softc *sc)
 int
 sfxge_ev_start(struct sfxge_softc *sc)
 {
-	struct sfxge_intr *intr;
+	struct sfxge_intr *intr __diagused;
 	int index;
 	int rc;
 
@@ -957,7 +957,7 @@ sfxge_ev_qinit(struct sfxge_softc *sc, unsigned int index)
 void
 sfxge_ev_fini(struct sfxge_softc *sc)
 {
-	struct sfxge_intr *intr;
+	struct sfxge_intr *intr __diagused;
 	int index;
 
 	intr = &sc->intr;
diff --git a/sys/dev/sfxge/sfxge_mcdi.c b/sys/dev/sfxge/sfxge_mcdi.c
index 00aaa73027a8..8107cdd42aaf 100644
--- a/sys/dev/sfxge/sfxge_mcdi.c
+++ b/sys/dev/sfxge/sfxge_mcdi.c
@@ -76,7 +76,7 @@ sfxge_mcdi_poll(struct sfxge_softc *sc, uint32_t timeout_us)
 	efx_nic_t *enp;
 	clock_t delay_total;
 	clock_t delay_us;
-	boolean_t aborted;
+	boolean_t aborted __diagused;
 
 	delay_total = 0;
 	delay_us = SFXGE_MCDI_POLL_INTERVAL_MIN;
@@ -140,7 +140,7 @@ static void
 sfxge_mcdi_ev_cpl(void *arg)
 {
 	struct sfxge_softc *sc;
-	struct sfxge_mcdi *mcdi;
+	struct sfxge_mcdi *mcdi __diagused;
 
 	sc = (struct sfxge_softc *)arg;
 	mcdi = &sc->mcdi;
diff --git a/sys/dev/sfxge/sfxge_rx.c b/sys/dev/sfxge/sfxge_rx.c
index 1f94b066dc78..1baab1ac17a6 100644
--- a/sys/dev/sfxge/sfxge_rx.c
+++ b/sys/dev/sfxge/sfxge_rx.c
@@ -223,7 +223,7 @@ sfxge_rx_qfill(struct sfxge_rxq *rxq, unsigned int target, boolean_t retrying)
 {
 	struct sfxge_softc *sc;
 	unsigned int index;
-	struct sfxge_evq *evq;
+	struct sfxge_evq *evq __diagused;
 	unsigned int batch;
 	unsigned int rxfill;
 	unsigned int mblksize;
@@ -815,7 +815,7 @@ sfxge_rx_qcomplete(struct sfxge_rxq *rxq, boolean_t eop)
 	int if_capenable = sc->ifnet->if_capenable;
 	int lro_enabled = if_capenable & IFCAP_LRO;
 	unsigned int index;
-	struct sfxge_evq *evq;
+	struct sfxge_evq *evq __diagused;
 	unsigned int completed;
 	unsigned int level;
 	struct mbuf *m;
@@ -844,7 +844,8 @@ sfxge_rx_qcomplete(struct sfxge_rxq *rxq, boolean_t eop)
 		/* Read the length from the pseudo header if required */
 		if (rx_desc->flags & EFX_PKT_PREFIX_LEN) {
 			uint16_t tmp_size;
-			int rc;
+			int rc __diagused;
+
 			rc = efx_pseudo_hdr_pkt_length_get(rxq->common,
 							   mtod(m, uint8_t *),
 							   &tmp_size);
diff --git a/sys/dev/sfxge/sfxge_tx.c b/sys/dev/sfxge/sfxge_tx.c
index 8be74a81bd8b..f2af6da9fcaf 100644
--- a/sys/dev/sfxge/sfxge_tx.c
+++ b/sys/dev/sfxge/sfxge_tx.c
@@ -331,10 +331,10 @@ sfxge_tx_qreap(struct sfxge_txq *txq)
 static void
 sfxge_tx_qlist_post(struct sfxge_txq *txq)
 {
-	unsigned int old_added;
+	unsigned int old_added __diagused;
 	unsigned int block_level;
 	unsigned int level;
-	int rc;
+	int rc __diagused;
 
 	SFXGE_TXQ_LOCK_ASSERT_OWNED(txq);
 
@@ -1433,7 +1433,7 @@ static void
 sfxge_tx_qunblock(struct sfxge_txq *txq)
 {
 	struct sfxge_softc *sc;
-	struct sfxge_evq *evq;
+	struct sfxge_evq *evq __diagused;
 
 	sc = txq->sc;
 	evq = sc->evq[txq->evq_index];
@@ -2001,7 +2001,7 @@ int
 sfxge_tx_init(struct sfxge_softc *sc)
 {
 	const efx_nic_cfg_t *encp = efx_nic_cfg_get(sc->enp);
-	struct sfxge_intr *intr;
+	struct sfxge_intr *intr __diagused;
 	int index;
 	int rc;