gcc/testsuite/gcc.dg/vect/vect-reduc-11.c

   1 /* { dg-require-effective-target vect_int } */
   2
   3 #include "tree-vect.h"
   4
   5 int x[1024], y[1024], z[1024];
   6
   7 int __attribute__((noinline,noclone))
   8 foo (int n)
   9 {
  10   int sum = 0;
  11   /* Can vectorize this.  */
  12   for (int i = 0; i < n; ++i)
  13     sum = (y[i] - (x[i] - sum));
  14   return sum;
  15 }
  16
  17 int __attribute__((noinline,noclone))
  18 bar (int n)
  19 {
  20   int sum = 0;
  21   /* Cannot vectorize this, sum is negated.  */
  22   for (int i = 0; i < n; ++i)
  23     sum = z[i] - (y[i] - (x[i] - sum));
  24   return sum;
  25 }
  26
  27 int
  28 main()
  29 {
  30   check_vect ();
  31   for (int i = 0; i < 1024; ++i)
  32     {
  33       x[i] = i;
  34       y[i] = i + 1;
  35       z[i] = 0;
  36       __asm__ volatile ("" : : : "memory");
  37     }
  38   if (foo (1024) != 1024)
  39     __builtin_abort ();
  40   if (bar (1023) != -1 || bar (1024) != 0)
  41     __builtin_abort ();
  42   return 0;
  43 }
  44
  45 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */