gcc/testsuite/gcc.dg/autopar/outer-4.c

/* { dg-do compile } */
/* { dg-options "-O2 -fno-tree-loop-vectorize -ftree-parallelize-loops=4 -fdump-tree-parloops-details -fdump-tree-optimized" } */

void abort (void);

int g_sum=0;
int x[500][500];

__attribute__((noinline))
void parloop (int N)
{
  int i, j;
  int sum;

  /* Double reduction is currently not supported, outer loop is not 
     parallelized.  Inner reduction is detected, inner loop is 
     parallelized.  */
  sum = 0;
  for (i = 0; i < N; i++)
    for (j = 0; j < N; j++)
      sum += x[i][j];

  g_sum = sum;
}

int main(void)
{
  parloop(500);

  return 0;
}


/* { dg-final { scan-tree-dump-times "parallelizing outer loop" 1 "parloops" { xfail *-*-* } } } */
/* { dg-final { scan-tree-dump-times "loopfn" 5 "optimized" } } */
/* { dg-final { cleanup-tree-dump "parloops" } } */
/* { dg-final { cleanup-tree-dump "optimized" } } */