[Bug rtl-optimization/67828] [6 Regression] wrong code at -O3 on x86_64-linux-gnu

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67828

--- Comment #6 from Zhendong Su <su at cs dot ucdavis.edu> ---
Below is another testcase that I believe exposes the same issue: 


---------------------------------------


int a = 2, b = 1, c = 1;

int
fn1 ()
{
  int d;
  for (; a; a--)
    {
      for (d = 0; d < 4; d++)
        {
          int k;
          if (c < 1)
            if (k)
              c = 0;
          if (b)
            continue;
          return 0;
        }
      b = !1;
    }
  return 0;
}

int
main ()
{
  fn1 ();

  if (a != 1) 
    __builtin_abort (); 

  return 0;
}