1  /* { dg-do compile } */
       2  /* { dg-options "-O2" } */
       3  
       4  #include <stdatomic.h>
       5  
       6  int
       7  tbit0 (_Atomic int* a, int n)
       8  {
       9  #define BIT (0x1 << n)
      10    return atomic_fetch_or (a, BIT) & BIT;
      11  #undef BIT
      12  }