gcc/testsuite/gcc.dg/tree-ssa/pr20256.c

   1 /* { dg-do compile } */
   2 /* { dg-options "-O2 -ftree-loop-linear -fdump-tree-ltrans-all" } */
   3 /* { dg-require-effective-target size32plus } */
   4
   5 int foo()
   6 {
   7   int x[2][2], y[2];
   8   int i, n, s;
   9
  10   /* This is a reduction: there is a scalar dependence that cannot be
  11      removed by rewriting IVs.  This code cannot and should not be
  12      transformed into a perfect loop.  */
  13   for (n = 0; n < 2; n++)
  14     {
  15       s = 0;
  16       for (i = 0; i < 2; i++)
  17         s += x[n][i]*y[i];
  18       s += 1;
  19     }
  20
  21   return s;
  22 }
  23
  24 /* { dg-final { scan-tree-dump-times "converted loop nest to perfect loop nest" 0 "ltrans"} } */
  25 /* { dg-final { cleanup-tree-dump "ltrans" } } */