gcc/testsuite/gcc.dg/vect/vect-reduc-in-order-3.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)
  12 {
  13   double r = 0;
  14   for (int i = 0; i < N; i += 4)
  15     {
  16       r += a[i] * 2.0;
  17       r += a[i + 1] * 3.0;
  18       r += a[i + 2] * 4.0;
  19       r += a[i + 3] * 5.0;
  20     }
  21   return r;
  22 }
  23
  24 int __attribute__ ((optimize (1)))
  25 main ()
  26 {
  27   double a[N];
  28   double r = 0;
  29   for (int i = 0; i < N; i++)
  30     {
  31       a[i] = (i * 0.1) * (i & 1 ? 1 : -1);
  32       r += a[i] * (i % 4 + 2);
  33       asm volatile ("" ::: "memory");
  34     }
  35   double res = reduc_plus_double (a);
  36   if (res != r)
  37     __builtin_abort ();
  38   return 0;
  39 }
  40
  41 /* { dg-final { scan-tree-dump-times {using an in-order \(fold-left\) reduction} 1 "vect" } } */
  42 /* { dg-final { scan-tree-dump-times {vectorizing stmts using SLP} 1 "vect" } } */