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

   1 /* A test for strength reduction of ivs with nonconstant step.  */
   2
   3 /* { dg-do compile } */
   4 /* { dg-options "-O1 -fdump-tree-optimized" } */
   5
   6 int bar (void);
   7
   8 int a[100];
   9
  10 void xxx (void)
  11 {
  12   int iter, step = bar ();
  13
  14   for (iter = 0; iter < 10; iter++)
  15     a[iter * step] = bar ();
  16 }
  17
  18 /* The array access should be strength reduced.  But to determine the value of
  19    the step, we need to calculate step * sizeof (int), thus we need to be
  20    a bit careful about which multiplications we disallow.  */
  21
  22 /* { dg-final { scan-tree-dump-times "step \\* \[^0-9\]" 0 "optimized" } } */
  23 /* { dg-final { scan-tree-dump-times "\[^0-9\] \\* step" 0 "optimized" } } */
  24
  25 /* { dg-final { cleanup-tree-dump "optimized" } } */