diff --git a/src/edit.c b/src/edit.c
index 45176d7..b5c129f 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -1722,11 +1722,19 @@
     {
 	aco_save_T	aco;
 
+	// Sync undo when the autocommand calls setline() or append(), so that
+	// it can be undone separately.
+	u_sync_once = 2;
+
 	// save and restore curwin and curbuf, in case the autocmd changes them
 	aucmd_prepbuf(&aco, curbuf);
 	apply_autocmds(EVENT_TEXTCHANGEDI, NULL, NULL, FALSE, curbuf);
 	aucmd_restbuf(&aco);
 	curbuf->b_last_changedtick = CHANGEDTICK(curbuf);
+
+	if (u_sync_once == 1)
+	    ins_need_undo = TRUE;
+	u_sync_once = 0;
     }
 
 #ifdef FEAT_INS_EXPAND