diff --git a/src/hsearch.c b/src/hsearch.c
index be0434c..dfe1404 100644
--- a/src/hsearch.c
+++ b/src/hsearch.c
@@ -80,9 +80,10 @@ static int resize(struct htab *htab, size_t nel)
 {
 	size_t newsize;
 	size_t i, j;
+	size_t oldmask = htab->mask;
 	struct elem *e, *newe;
 	struct elem *oldtab = htab->elems;
-	struct elem *oldend = htab->elems + htab->mask + 1;
+	struct elem *oldend;
 
 	if (nel > MAXSIZE)
 		nel = MAXSIZE;
@@ -95,6 +96,8 @@ static int resize(struct htab *htab, size_t nel)
 	htab->mask = newsize - 1;
 	if (!oldtab)
 		return 1;
+
+	oldend = oldtab + oldmask + 1;
 	for (e = oldtab; e < oldend; e++)
 		if (e->item.key) {
 			for (i=e->hash,j=1; ; i+=j++) {