gcc/testsuite/gcc.dg/tree-ssa/predcom-1.c

   1 /* { dg-do compile } */
   2 /* { dg-do run } */
   3 /* { dg-options "-O2 -fpredictive-commoning -fdump-tree-pcom-details" } */
   4
   5 void abort (void);
   6
   7 unsigned fib[1000];
   8
   9 void count_fib(void)
  10 {
  11   int i;
  12
  13   fib[0] = 0;
  14   fib[1] = 1;
  15   for (i = 2; i < 1000; i++)
  16     fib[i] = (fib[i-1] + fib[i - 2]) & 0xffff;
  17 }
  18
  19 unsigned avg[1000];
  20
  21 void count_averages(int n)
  22 {
  23   int i;
  24
  25   for (i = 1; i < n; i++)
  26     avg[i] = (((unsigned long) fib[i - 1] + fib[i] + fib[i + 1]) / 3) & 0xffff;
  27 }
  28
  29 int main(void)
  30 {
  31   count_fib ();
  32   count_averages (999);
  33
  34   if (fib[19] != 4181 || avg[19] != 4510)
  35     abort ();
  36
  37   if (fib[999] != 162 || avg[998] != 21953)
  38     abort ();
  39
  40   return 0;
  41 }
  42
  43 /* Verify that both loops were transformed and unrolled.  */
  44 /* { dg-final { scan-tree-dump-times "Unrolling 2 times." 2 "pcom"} } */
  45
  46 /* Also check that we undid the transformation previously made by PRE.  */
  47 /* { dg-final { scan-tree-dump-times "looparound ref" 1 "pcom"} } */
  48
  49 /* { dg-final { cleanup-tree-dump "pcom" } } */