modernc.org/ccgo/v3@v3.16.14/lib/testdata/gcc-9.1.0/gcc/testsuite/gcc.c-torture/execute/pr59643.c (about)

     1  /* PR tree-optimization/59643 */
     2  
     3  #define N 32
     4  
     5  __attribute__((noinline, noclone)) void
     6  foo (double *a, double *b, double *c, double d, double e, int n)
     7  {
     8    int i;
     9    for (i = 1; i < n - 1; i++)
    10      a[i] = d * (b[i] + c[i] + a[i - 1] + a[i + 1]) + e * a[i];
    11  }
    12  
    13  double expected[] = {
    14    0.0, 10.0, 44.0, 110.0, 232.0, 490.0, 1020.0, 2078.0, 4152.0, 8314.0,
    15    16652.0, 33326.0, 66664.0, 133354.0, 266748.0, 533534.0, 1067064.0,
    16    2134138.0, 4268300.0, 8536622.0, 17073256.0, 34146538.0, 68293116.0,
    17    136586270.0, 273172536.0, 546345082.0, 1092690188.0, 2185380398.0,
    18    4370760808.0, 8741521642.0, 17483043324.0, 6.0
    19  };
    20  
    21  int
    22  main ()
    23  {
    24    int i;
    25    double a[N], b[N], c[N];
    26    if (__DBL_MANT_DIG__ <= 35)
    27      return 0;
    28    for (i = 0; i < N; i++)
    29      {
    30        a[i] = (i & 3) * 2.0;
    31        b[i] = (i & 7) - 4;
    32        c[i] = i & 7;
    33      }
    34    foo (a, b, c, 2.0, 3.0, N);
    35    for (i = 0; i < N; i++)
    36      if (a[i] != expected[i])
    37        __builtin_abort ();
    38    return 0;
    39  }