diff --git a/sys/x86/x86/local_apic.c b/sys/x86/x86/local_apic.c
index c404188e578..ac3dfa4ca1d 100644
--- a/sys/x86/x86/local_apic.c
+++ b/sys/x86/x86/local_apic.c
@@ -2178,7 +2178,7 @@ static void
 native_lapic_ipi_free(int vector)
 {
 	struct gate_descriptor *ip;
-	long func;
+	long func __diagused;
 
 	KASSERT(vector >= IPI_DYN_FIRST && vector <= IPI_DYN_LAST,
 	    ("%s: invalid vector %d", __func__, vector));