issue24449.go

     1  // run
     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  package main
     8  
     9  import (
    10  	"sync/atomic"
    11  )
    12  
    13  var cnt32 int32
    14  
    15  //go:noinline
    16  func test32(a, b []int) bool {
    17  	// Try to generate flag value, issue atomic
    18  	// adds and then re-use the flag value to see if
    19  	// the atomic add has clobbered them.
    20  	atomic.AddInt32(&cnt32, 1)
    21  	if len(a) == len(b) {
    22  		atomic.AddInt32(&cnt32, 2)
    23  	}
    24  	atomic.AddInt32(&cnt32, 4)
    25  	if len(a) >= len(b) {
    26  		atomic.AddInt32(&cnt32, 8)
    27  	}
    28  	if len(a) <= len(b) {
    29  		atomic.AddInt32(&cnt32, 16)
    30  	}
    31  	return atomic.LoadInt32(&cnt32) == 31
    32  }
    33  
    34  var cnt64 int64
    35  
    36  //go:noinline
    37  func test64(a, b []int) bool {
    38  	// Try to generate flag value, issue atomic
    39  	// adds and then re-use the flag value to see if
    40  	// the atomic add has clobbered them.
    41  	atomic.AddInt64(&cnt64, 1)
    42  	if len(a) == len(b) {
    43  		atomic.AddInt64(&cnt64, 2)
    44  	}
    45  	atomic.AddInt64(&cnt64, 4)
    46  	if len(a) >= len(b) {
    47  		atomic.AddInt64(&cnt64, 8)
    48  	}
    49  	if len(a) <= len(b) {
    50  		atomic.AddInt64(&cnt64, 16)
    51  	}
    52  	return atomic.LoadInt64(&cnt64) == 31
    53  }
    54  
    55  func main() {
    56  	if !test32([]int{}, []int{}) {
    57  		panic("test32")
    58  	}
    59  	if !test64([]int{}, []int{}) {
    60  		panic("test64")
    61  	}
    62  }
    63
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