diff --git a/commit.c b/commit.c
index d20b14ee3e..03e73f323a 100644
--- a/commit.c
+++ b/commit.c
@@ -747,7 +747,7 @@ struct commit_list *reduce_heads(struct commit_list *heads)
 
 		num_other = 0;
 		for (q = heads; q; q = q->next) {
-			if (p == q)
+			if (p->item == q->item)
 				continue;
 			other[num_other++] = q->item;
 		}
diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh
index 72ef2e55d9..f035ea376e 100755
--- a/t/t7600-merge.sh
+++ b/t/t7600-merge.sh
@@ -479,4 +479,15 @@ test_expect_success 'merge log message' '
 
 test_debug 'gitk --all'
 
+test_expect_success 'merge c1 with c0, c2, c0, and c1' '
+       git reset --hard c1 &&
+       git config branch.master.mergeoptions "" &&
+       test_tick &&
+       git merge c0 c2 c0 c1 &&
+       verify_merge file result.1-5 &&
+       verify_parents $c1 $c2
+'
+
+test_debug 'gitk --all'
+
 test_done