gcc/testsuite/gcc.dg/sabd_1.c

   1 /* { dg-do run } */
   2 /* { dg-options "-O3 -fwrapv" } */
   3 /* Make sure vectorized absolute difference behaves same as scalar version.  */
   4
   5 #define N 16
   6 signed char a[] = {-100, -100, -100, -100,-100, -100, -100, -100, -100, -100, -100, -100, -100, -100, -100, -100 };
   7 signed char b[] = { 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100 };
   8
   9 signed char out[N];
  10
  11 __attribute__ ((noinline,noipa))
  12 void
  13 foo (void)
  14 {
  15   for (int i = 0; i < N; i++)
  16     {
  17       signed char diff = b[i] - a[i];
  18       out[i] = diff > 0 ? diff : -diff;
  19     }
  20 }
  21
  22 signed char out2[N];
  23
  24 __attribute__ ((noinline,noipa))
  25 void
  26 foo_scalar (void)
  27 {
  28   for (int i = 0; i < N; i++)
  29     {
  30       asm volatile ("");
  31       signed char diff = b[i] - a[i];
  32       out2[i] = diff > 0 ? diff : -diff;
  33     }
  34 }
  35
  36 int
  37 main (void)
  38 {
  39   foo ();
  40   foo_scalar ();
  41   for (int i = 0; i < N; i++)
  42     if (out[i] != out2[i])
  43       __builtin_abort ();
  44
  45   return 0;
  46 }
  47