diff --git a/sys/fs/tmpfs/tmpfs.h b/sys/fs/tmpfs/tmpfs.h
index 70ed066ef0f..eda1c3b12c2 100644
--- a/sys/fs/tmpfs/tmpfs.h
+++ b/sys/fs/tmpfs/tmpfs.h
@@ -516,7 +516,6 @@ tmpfs_update(struct vnode *vp)
  * Convenience macros to simplify some logical expressions.
  */
 #define IMPLIES(a, b) (!(a) || (b))
-#define IFF(a, b) (IMPLIES(a, b) && IMPLIES(b, a))
 
 /*
  * Checks that the directory entry pointed by 'de' matches the name 'name'
diff --git a/sys/fs/tmpfs/tmpfs_subr.c b/sys/fs/tmpfs/tmpfs_subr.c
index cfd4787fb71..351ca825f20 100644
--- a/sys/fs/tmpfs/tmpfs_subr.c
+++ b/sys/fs/tmpfs/tmpfs_subr.c
@@ -547,8 +547,8 @@ tmpfs_alloc_node(struct mount *mp, struct tmpfs_mount *tmp, enum vtype type,
 	 * allocated, this must be the request to do it. */
 	MPASS(IMPLIES(tmp->tm_root == NULL, parent == NULL && type == VDIR));
 
-	MPASS(IFF(type == VLNK, target != NULL));
-	MPASS(IFF(type == VBLK || type == VCHR, rdev != VNOVAL));
+	MPASS((type == VLNK) ^ (target == NULL));
+	MPASS((type == VBLK || type == VCHR) ^ (rdev == VNOVAL));
 
 	if (tmp->tm_nodes_inuse >= tmp->tm_nodes_max)
 		return (ENOSPC);