diff --git a/src/memline.c b/src/memline.c
index 5356369..a0b6429 100644
--- a/src/memline.c
+++ b/src/memline.c
@@ -1312,7 +1312,7 @@
     }
 
 #ifdef FEAT_CRYPT
-    for (i = 0; i < (int)(sizeof(id1_codes) / sizeof(int)); ++i)
+    for (i = 0; i < (int)ARRAY_LENGTH(id1_codes); ++i)
 	if (id1_codes[i] == b0p->b0_id[1])
 	    b0_cm = i;
     if (b0_cm > 0)