gcc/testsuite/gcc.dg/tree-ssa/loop-4.c

   1 /* A test for strength reduction and induction variable elimination.  */
   2
   3 /* { dg-do compile } */
   4 /* { dg-options "-O1 -fdump-tree-optimized" } */
   5 /* { dg-require-effective-target size32plus } */
   6
   7 /* Size of this structure should be sufficiently weird so that no memory
   8    addressing mode applies.  */
   9
  10 struct bla
  11 {
  12   char x[187];
  13   int y;
  14   char z[253];
  15 } arr_base[100];
  16
  17 int foo(void);
  18
  19 void xxx(void)
  20 {
  21   int iter;
  22
  23   for (iter = 0; iter < 100; iter++)
  24     arr_base[iter].y = foo ();
  25 }
  26
  27 /* Access to arr_base[iter].y should be strength reduced.  Depending on
  28    whether we have an addressing mode of type [base + offset], one of the
  29    following forms might get chosen:
  30
  31    -- induction variable with base &arr_base[0].y, the memory access of
  32       form *iv = ...
  33    -- induction variable with base 0, the memory access of form
  34       *(iv + &arr_base[0].y) = ...
  35
  36    In any case, we should not have any multiplication.  */
  37
  38 /* { dg-final { scan-tree-dump-times " \\* \[^\\n\\r\]*=" 0 "optimized" } } */
  39 /* { dg-final { scan-tree-dump-times "\[^\\n\\r\]*= \\* " 0 "optimized" } } */
  40 /* { dg-final { scan-tree-dump-times " MEM" 1 "optimized" } } */
  41
  42 /* And the original induction variable should be eliminated.  */
  43
  44 /* { dg-final { scan-tree-dump-times "iter" 0 "optimized" } } */
  45