diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 4391504a91..99b6329399 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -667,9 +667,57 @@ static void add_family_to_write_order(struct object_entry **wo,
 	add_descendants_to_write_order(wo, endp, root);
 }
 
+static void compute_layer_order(struct object_entry **wo, unsigned int *wo_end)
+{
+	unsigned int i, last_untagged;
+	struct object_entry *objects = to_pack.objects;
+
+	for (i = 0; i < to_pack.nr_objects; i++) {
+		if (objects[i].tagged)
+			break;
+		add_to_write_order(wo, wo_end, &objects[i]);
+	}
+	last_untagged = i;
+
+	/*
+	 * Then fill all the tagged tips.
+	 */
+	for (; i < to_pack.nr_objects; i++) {
+		if (objects[i].tagged)
+			add_to_write_order(wo, wo_end, &objects[i]);
+	}
+
+	/*
+	 * And then all remaining commits and tags.
+	 */
+	for (i = last_untagged; i < to_pack.nr_objects; i++) {
+		if (oe_type(&objects[i]) != OBJ_COMMIT &&
+		    oe_type(&objects[i]) != OBJ_TAG)
+			continue;
+		add_to_write_order(wo, wo_end, &objects[i]);
+	}
+
+	/*
+	 * And then all the trees.
+	 */
+	for (i = last_untagged; i < to_pack.nr_objects; i++) {
+		if (oe_type(&objects[i]) != OBJ_TREE)
+			continue;
+		add_to_write_order(wo, wo_end, &objects[i]);
+	}
+
+	/*
+	 * Finally all the rest in really tight order
+	 */
+	for (i = last_untagged; i < to_pack.nr_objects; i++) {
+		if (!objects[i].filled)
+			add_family_to_write_order(wo, wo_end, &objects[i]);
+	}
+}
+
 static struct object_entry **compute_write_order(void)
 {
-	unsigned int i, wo_end, last_untagged;
+	unsigned int i, wo_end;
 
 	struct object_entry **wo;
 	struct object_entry *objects = to_pack.objects;
@@ -705,47 +753,9 @@ static struct object_entry **compute_write_order(void)
 	 * we see a tagged tip.
 	 */
 	ALLOC_ARRAY(wo, to_pack.nr_objects);
-	for (i = wo_end = 0; i < to_pack.nr_objects; i++) {
-		if (objects[i].tagged)
-			break;
-		add_to_write_order(wo, &wo_end, &objects[i]);
-	}
-	last_untagged = i;
+	wo_end = 0;
 
-	/*
-	 * Then fill all the tagged tips.
-	 */
-	for (; i < to_pack.nr_objects; i++) {
-		if (objects[i].tagged)
-			add_to_write_order(wo, &wo_end, &objects[i]);
-	}
-
-	/*
-	 * And then all remaining commits and tags.
-	 */
-	for (i = last_untagged; i < to_pack.nr_objects; i++) {
-		if (oe_type(&objects[i]) != OBJ_COMMIT &&
-		    oe_type(&objects[i]) != OBJ_TAG)
-			continue;
-		add_to_write_order(wo, &wo_end, &objects[i]);
-	}
-
-	/*
-	 * And then all the trees.
-	 */
-	for (i = last_untagged; i < to_pack.nr_objects; i++) {
-		if (oe_type(&objects[i]) != OBJ_TREE)
-			continue;
-		add_to_write_order(wo, &wo_end, &objects[i]);
-	}
-
-	/*
-	 * Finally all the rest in really tight order
-	 */
-	for (i = last_untagged; i < to_pack.nr_objects; i++) {
-		if (!objects[i].filled)
-			add_family_to_write_order(wo, &wo_end, &objects[i]);
-	}
+	compute_layer_order(wo, &wo_end);
 
 	if (wo_end != to_pack.nr_objects)
 		die("ordered %u objects, expected %"PRIu32, wo_end, to_pack.nr_objects);