1  /* { dg-do run } */
       2  /* { dg-set-target-env-var OMP_CANCELLATION "true" } */
       3  
       4  #include <stdlib.h>
       5  #include <omp.h>
       6  
       7  struct T { struct T *children[2]; int val; };
       8  
       9  struct T *
      10  search (struct T *tree, int val, int lvl)
      11  {
      12    if (tree == NULL || tree->val == val)
      13      return tree;
      14    struct T *ret = NULL;
      15    int i;
      16    for (i = 0; i < 2; i++)
      17      #pragma omp task shared(ret) if(lvl < 10)
      18      {
      19        struct T *r = search (tree->children[i], val, lvl + 1);
      20        if (r)
      21  	{
      22  	  #pragma omp atomic write
      23  	  ret = r;
      24  	  #pragma omp cancel taskgroup
      25  	}
      26      }
      27    #pragma omp taskwait
      28    return ret;
      29  }
      30  
      31  struct T *
      32  searchp (struct T *tree, int val)
      33  {
      34    struct T *ret;
      35    #pragma omp parallel shared(ret) firstprivate (tree, val)
      36    #pragma omp single
      37    #pragma omp taskgroup
      38    ret = search (tree, val, 0);
      39    return ret;
      40  }
      41  
      42  int
      43  main ()
      44  {
      45    /* Must be power of two minus 1.  */
      46    int size = 0x7ffff;
      47    struct T *trees = (struct T *) malloc (size * sizeof (struct T));
      48    if (trees == NULL)
      49      return 0;
      50    int i, l = 1, b = 0;
      51    for (i = 0; i < size; i++)
      52      {
      53        if (i == l)
      54  	{
      55  	  b = l;
      56  	  l = l * 2 + 1;
      57  	}
      58        trees[i].val = i;
      59        trees[i].children[0] = l == size ? NULL : &trees[l + (i - b) * 2];
      60        trees[i].children[1] = l == size ? NULL : &trees[l + (i - b) * 2 + 1];
      61      }
      62    for (i = 0; i < 50; i++)
      63      {
      64        int v = random () & size;
      65        if (searchp (&trees[0], v) != &trees[v])
      66  	abort ();
      67      }
      68    free (trees);
      69    return 0;
      70  }