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https://github.com/golang/go
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ae10914e67
The atomic add instructions modify the condition code and so need to be marked as clobbering flags. Fixes #24449. Change-Id: Ic69c8d775fbdbfb2a56c5e0cfca7a49c0d7f6897 Reviewed-on: https://go-review.googlesource.com/101455 Run-TryBot: Michael Munday <mike.munday@ibm.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
63 lines
1.2 KiB
Go
63 lines
1.2 KiB
Go
// run
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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import (
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"sync/atomic"
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)
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var cnt32 int32
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//go:noinline
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func test32(a, b []int) bool {
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// Try to generate flag value, issue atomic
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// adds and then re-use the flag value to see if
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// the atomic add has clobbered them.
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atomic.AddInt32(&cnt32, 1)
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if len(a) == len(b) {
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atomic.AddInt32(&cnt32, 2)
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}
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atomic.AddInt32(&cnt32, 4)
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if len(a) >= len(b) {
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atomic.AddInt32(&cnt32, 8)
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}
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if len(a) <= len(b) {
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atomic.AddInt32(&cnt32, 16)
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}
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return atomic.LoadInt32(&cnt32) == 31
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}
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var cnt64 int64
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//go:noinline
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func test64(a, b []int) bool {
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// Try to generate flag value, issue atomic
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// adds and then re-use the flag value to see if
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// the atomic add has clobbered them.
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atomic.AddInt64(&cnt64, 1)
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if len(a) == len(b) {
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atomic.AddInt64(&cnt64, 2)
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}
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atomic.AddInt64(&cnt64, 4)
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if len(a) >= len(b) {
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atomic.AddInt64(&cnt64, 8)
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}
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if len(a) <= len(b) {
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atomic.AddInt64(&cnt64, 16)
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}
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return atomic.LoadInt64(&cnt64) == 31
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}
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func main() {
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if !test32([]int{}, []int{}) {
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panic("test32")
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}
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if !test64([]int{}, []int{}) {
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panic("test64")
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}
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}
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