1 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t 2>&1 | FileCheck %s
2 #include "test.h"
3 
4 long long Data;
5 long long Sync;
6 
7 void *Thread1(void *x) {
8   Data++;
9   __atomic_store_n(&Sync, 1, __ATOMIC_RELEASE);
10   barrier_wait(&barrier);
11   barrier_wait(&barrier);
12   return NULL;
13 }
14 
15 void *Thread2(void *x) {
16   barrier_wait(&barrier);
17   if (__atomic_load_n(&Sync, __ATOMIC_RELAXED) != 1)
18     exit(0);
19   // This store must terminate release sequence of the store in Thread1,
20   // thus tsan must detect race between Thread1 and main on Data.
21   __atomic_store_n(&Sync, 2, __ATOMIC_RELEASE);
22   barrier_wait(&barrier);
23   return NULL;
24 }
25 
26 int main() {
27   barrier_init(&barrier, 3);
28   pthread_t t[2];
29   pthread_create(&t[0], NULL, Thread1, NULL);
30   pthread_create(&t[1], NULL, Thread2, NULL);
31   barrier_wait(&barrier);
32   barrier_wait(&barrier);
33   if (__atomic_load_n(&Sync, __ATOMIC_ACQUIRE) != 2)
34     exit(0);
35   if (Data != 1)
36     exit(0);
37   pthread_join(t[0], NULL);
38   pthread_join(t[1], NULL);
39   fprintf(stderr, "DONE\n");
40   return 0;
41 }
42 
43 // CHECK: WARNING: ThreadSanitizer: data race
44 // CHECK:   Read
45 // CHECK:     #0 main
46 // CHECK:   Previous write
47 // CHECK:     #0 Thread1
48 // CHECK:   Location is global 'Data'
49 // CHECK: DONE
50