gcc/testsuite/gcc.dg/vect/vect-reduc-in-order-1.c

   1 /* { dg-do run { xfail { { i?86-*-* x86_64-*-* } && ia32 } } } */
   2 /* { dg-require-effective-target vect_double } */
   3 /* { dg-add-options ieee } */
   4 /* { dg-additional-options "-fno-fast-math" } */
   5
   6 #include "tree-vect.h"
   7
   8 #define N (VECTOR_BITS * 17)
   9
  10 double __attribute__ ((noinline, noclone))
  11 reduc_plus_double (double *a, double *b)
  12 {
  13   double r = 0, q = 3;
  14   for (int i = 0; i < N; i++)
  15     {
  16       r += a[i];
  17       q -= b[i];
  18     }
  19   return r * q;
  20 }
  21
  22 int __attribute__ ((optimize (1)))
  23 main ()
  24 {
  25   double a[N];
  26   double b[N];
  27   double r = 0, q = 3;
  28   for (int i = 0; i < N; i++)
  29     {
  30       a[i] = (i * 0.1) * (i & 1 ? 1 : -1);
  31       b[i] = (i * 0.3) * (i & 1 ? 1 : -1);
  32       r += a[i];
  33       q -= b[i];
  34       asm volatile ("" ::: "memory");
  35     }
  36   double res = reduc_plus_double (a, b);
  37   if (res != r * q)
  38     __builtin_abort ();
  39   return 0;
  40 }
  41
  42 /* { dg-final { scan-tree-dump-times {using an in-order \(fold-left\) reduction} 2 "vect" } } */