[Bug tree-optimization/53265] Warn when undefined behavior implies smaller iteration count

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53265



--- Comment #22 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-03-12 
21:47:38 UTC ---

Short C testcase reproducing the exp_ch7.adb issue (for -O2):

void bar (int);



__attribute__((noinline)) static int

foo (int x)

{

  int i = 1;

  if (x > 1)

    do

      bar (i);

    while (++i != x);

}



void

baz (void)

{

  foo (1);

  foo (1);

  foo (1);

}