1// compile
2
3// Copyright 2018 The Go Authors. All rights reserved.
4// Use of this source code is governed by a BSD-style
5// license that can be found in the LICENSE file.
6
7// Make sure dead write barriers are handled correctly.
8
9package main
10
11func f(p **int) {
12	// The trick here is to eliminate the block containing the write barrier,
13	// but only after the write barrier branches are inserted.
14	// This requires some delicate code.
15	i := 0
16	var b []bool
17	var s string
18	for true {
19		if b[i] {
20			var a []string
21			s = a[len(s)]
22			i = 0
23		}
24		*p = nil
25	}
26}
27