Increase index number for creating temp vars' name.

gcc/cp
    * coroutines.cc (maybe_promote_captured_temps): Increase the index
    number for temporary variables' name.

gcc/cp/ChangeLog

+2020-02-05  Bin Cheng  <bin.cheng@linux.alibaba.com>
+
+	* coroutines.cc (maybe_promote_captured_temps): Increase the index
+	number for temporary variables' name.
+
 2020-02-05  Jun Ma <JunMa@linux.alibaba.com>
 
 	* coroutines.cc (build_co_await): Call convert_from_reference

gcc/cp/coroutines.cc

@@ -2676,12 +2676,12 @@ maybe_promote_captured_temps (tree *stmt, void *d)
       /* Collected the scope vars we need move the temps to regular. */
       tree aw_bind_body = push_stmt_list ();
       tree varlist = NULL_TREE;
-      unsigned vnum = 0;
+      int vnum = -1;
       while (!awpts->to_replace->is_empty ())
 	{
 	  size_t bufsize = sizeof ("__aw_.tmp.") + 20;
 	  char *buf = (char *) alloca (bufsize);
-	  snprintf (buf, bufsize, "__aw_%d.tmp.%d", awpts->count, vnum);
+	  snprintf (buf, bufsize, "__aw_%d.tmp.%d", awpts->count, ++vnum);
 	  tree to_replace = awpts->to_replace->pop ();
 	  tree orig_temp;
 	  if (TREE_CODE (to_replace) == CO_AWAIT_EXPR)