gcc/testsuite/gcc.dg/tree-ssa/ldist-8.c

   1 /* { dg-do compile } */
   2 /* { dg-options "-O2 -ftree-loop-distribution -fdump-tree-ldist-all" } */
   3
   4 int loop1 (int k)
   5 {
   6   unsigned int i;
   7   int a[1000], b[1000], c[1000], d[1000];
   8
   9   for (i = 2; i < (1000-1); i ++)
  10     {
  11       a[i] = k * i; /* S1 */
  12       b[i] = a[i+1] + k; /* S2 */
  13       c[i] = a[i-1] + b[i-1] + d[i-1]; /* S3 */
  14       d[i] = a[i-1] + b[i+1] + k + i; /* S4 */
  15     }
  16   /* Dependences:
  17      S1->S2 (anti, level 1)
  18      S1->S3 (flow, level 1)
  19      S1->S4 (flow, level 1)
  20      S2->S3 (flow, level 1)
  21      S2->S4 (anti, level 1)
  22      S4->S3 (flow, level 1)
  23
  24      Two partitions: {S1, S2, S4} produce information that is consumed in {S3}.
  25
  26      So that means that the current cost model will also fuse these
  27      two partitions into a single one for avoiding cache misses.
  28   */
  29
  30   return a[1000-2] + b[1000-1] + c[1000-2] + d[1000-2];
  31 }
  32
  33 /* { dg-final { scan-tree-dump-times "distributed: split to 2 loops" 0 "ldist" } } */
  34 /* { dg-final { cleanup-tree-dump "ldist" } } */