From f6ad4dcef54c5ce997a4bad5a6d86de229015700 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Tue, 16 Apr 2024 21:25:22 +0200 Subject: Adding upstream version 1.22.1. Signed-off-by: Daniel Baumann --- test/atomicload.go | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 test/atomicload.go (limited to 'test/atomicload.go') diff --git a/test/atomicload.go b/test/atomicload.go new file mode 100644 index 0000000..76f1ad4 --- /dev/null +++ b/test/atomicload.go @@ -0,0 +1,45 @@ +// run + +// Copyright 2016 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. + +// Check that we do loads exactly once. The SSA backend +// once tried to do the load in f twice, once sign extended +// and once zero extended. This can cause problems in +// racy code, particularly sync/mutex. + +package main + +func f(p *byte) bool { + x := *p + a := int64(int8(x)) + b := int64(uint8(x)) + return a == b +} + +func main() { + var x byte + const N = 1000000 + c := make(chan struct{}) + go func() { + for i := 0; i < N; i++ { + x = 1 + } + c <- struct{}{} + }() + go func() { + for i := 0; i < N; i++ { + x = 2 + } + c <- struct{}{} + }() + + for i := 0; i < N; i++ { + if !f(&x) { + panic("non-atomic load!") + } + } + <-c + <-c +} -- cgit v1.2.3