diff --git a/read-cache.c b/read-cache.c
index 2f9e21c897..4cdc7bb661 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -2686,8 +2686,8 @@ static int ce_write_entry(struct hashfile *f, struct cache_entry *ce,
 		int common, to_remove, prefix_size;
 		unsigned char to_remove_vi[16];
 		for (common = 0;
-		     (ce->name[common] &&
-		      common < previous_name->len &&
+		     (common < previous_name->len &&
+		      ce->name[common] &&
 		      ce->name[common] == previous_name->buf[common]);
 		     common++)
 			; /* still matching */