diff --git a/src/spellfile.c b/src/spellfile.c
index 8b1a3a6..00ef019 100644
--- a/src/spellfile.c
+++ b/src/spellfile.c
@@ -1585,7 +1585,7 @@
     int		prefixtree,	/* TRUE for the prefix tree */
     int		prefixcnt)	/* when "prefixtree" is TRUE: prefix count */
 {
-    int		len;
+    long	len;
     int		idx;
     char_u	*bp;
     idx_T	*ip;
@@ -1595,7 +1595,7 @@
     len = get4c(fd);
     if (len < 0)
 	return SP_TRUNCERROR;
-    if (len >= 0x3ffffff)
+    if (len >= LONG_MAX / (long)sizeof(int))
 	/* Invalid length, multiply with sizeof(int) would overflow. */
 	return SP_FORMERROR;
     if (len > 0)