gcc/testsuite/gcc.dg/vect/vect-recurr-4.c

   1 /* { dg-require-effective-target vect_int } */
   2 /* { dg-require-effective-target vect_perm } */
   3
   4 #include "tree-vect.h"
   5
   6 void __attribute__((noipa))
   7 foo (int * __restrict__ a, int * __restrict__ b, int * __restrict__ c)
   8 {
   9   int t1 = *c;
  10   int t2 = *c;
  11   for (int i = 0; i < 64; i+=2)
  12     {
  13       b[i] = a[i] - t1;
  14       t1 = a[i];
  15       b[i+1] = a[i+1] - t2;
  16       t2 = a[i+1];
  17     }
  18 }
  19
  20 int a[64], b[64];
  21
  22 int
  23 main ()
  24 {
  25   check_vect ();
  26   for (int i = 0; i < 64; ++i)
  27     {
  28       a[i] = i;
  29       __asm__ volatile ("" ::: "memory");
  30     }
  31   int c = 7;
  32   foo (a, b, &c);
  33 #pragma GCC novector
  34   for (int i = 2; i < 64; i+=2)
  35     if (b[i] != a[i] - a[i-2]
  36         || b[i+1] != a[i+1] - a[i-1])
  37       abort ();
  38   if (b[0] != -7 || b[1] != -6)
  39     abort ();
  40   return 0;
  41 }
  42
  43 /* { dg-final { scan-tree-dump "vectorized 1 loops in function" "vect" } } */