gcc/testsuite/gcc.c-torture/execute/pr47538.c

   1 /* PR tree-optimization/47538 */
   2
   3 struct S
   4 {
   5   double a, b, *c;
   6   unsigned long d;
   7 };
   8
   9 __attribute__((noinline, noclone)) void
  10 foo (struct S *x, const struct S *y)
  11 {
  12   const unsigned long n = y->d + 1;
  13   const double m = 0.25 * (y->b - y->a);
  14   x->a = y->a;
  15   x->b = y->b;
  16   if (n == 1)
  17     {
  18       x->c[0] = 0.;
  19     }
  20   else if (n == 2)
  21     {
  22       x->c[1] = m * y->c[0];
  23       x->c[0] = 2.0 * x->c[1];
  24     }
  25   else
  26     {
  27       double o = 0.0, p = 1.0;
  28       unsigned long i;
  29
  30       for (i = 1; i <= n - 2; i++)
  31         {
  32           x->c[i] = m * (y->c[i - 1] - y->c[i + 1]) / (double) i;
  33           o += p * x->c[i];
  34           p = -p;
  35         }
  36       x->c[n - 1] = m * y->c[n - 2] / (n - 1.0);
  37       o += p * x->c[n - 1];
  38       x->c[0] = 2.0 * o;
  39     }
  40 }
  41
  42 int
  43 main (void)
  44 {
  45   struct S x, y;
  46   double c[4] = { 10, 20, 30, 40 }, d[4], e[4] = { 118, 118, 118, 118 };
  47
  48   y.a = 10;
  49   y.b = 6;
  50   y.c = c;
  51   x.c = d;
  52   y.d = 3;
  53   __builtin_memcpy (d, e, sizeof d);
  54   foo (&x, &y);
  55   if (d[0] != 0 || d[1] != 20 || d[2] != 10 || d[3] != -10)
  56     __builtin_abort ();
  57   y.d = 2;
  58   __builtin_memcpy (d, e, sizeof d);
  59   foo (&x, &y);
  60   if (d[0] != 60 || d[1] != 20 || d[2] != -10 || d[3] != 118)
  61     __builtin_abort ();
  62   y.d = 1;
  63   __builtin_memcpy (d, e, sizeof d);
  64   foo (&x, &y);
  65   if (d[0] != -20 || d[1] != -10 || d[2] != 118 || d[3] != 118)
  66     __builtin_abort ();
  67   y.d = 0;
  68   __builtin_memcpy (d, e, sizeof d);
  69   foo (&x, &y);
  70   if (d[0] != 0 || d[1] != 118 || d[2] != 118 || d[3] != 118)
  71     __builtin_abort ();
  72   return 0;
  73 }