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// run
// Copyright 2025 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import "runtime"
const C = 16
type T [C * C]byte
func main() {
var ts []*T
for i := 0; i < 100; i++ {
t := new(T)
// Save every even object.
if i%2 == 0 {
ts = append(ts, t)
}
}
// Make sure the odd objects are collected.
runtime.GC()
for _, t := range ts {
f(t, C, C)
}
}
//go:noinline
func f(t *T, i, j uint) {
if i == 0 || i > C || j == 0 || j > C {
return // gets rid of bounds check below (via prove pass)
}
p := &t[i*j-1]
*p = 0
runtime.GC()
*p = 0
// This goes badly if compiled to
// q := &t[i*j]
// *(q-1) = 0
// runtime.GC()
// *(q-1) = 0
// as at the GC call, q is an invalid pointer
// (it points past the end of t's allocation).
}
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