[Bug tree-optimization/58248] [4.9 Regression] wrong code at -O3 on x86_64-linux-gnu

["su at cs dot ucdavis.edu" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58248

--- Comment #5 from Zhendong Su <su at cs dot ucdavis.edu> ---
(In reply to Jakub Jelinek from comment #4)
> No, the only change I've made to this testcase was instead of using
> printf use if (c != 1) __builtin_abort ();.

I checked the modified test case below: 

---------

struct S
{
  int u;
}; 

int a = 1, b, c = 1, e, *f, *g;

static struct S d = {6};

void foo (int *p)
{
  c &= a != *p;
}

int main ()
{
  struct S h = d;
  int **i = &f;
  *i = g = &b;
  for (; h.u; h.u--)
    {
      for (e = 0; e < 2; e++)
        {
      foo (*i);
      *g = 0 > **i;
        }
      *f = 0;
    }

  if (c != 1)
    __builtin_abort (); 

  return 0;
}

---------

The log: 

$ gcc-trunk -O3 small.c
$ a.out
Aborted (core dumped)
$ gcc-trunk -O2 small.c
$ a.out
$ gcc-4.8 -O3 small.c
$ a.out
$ 

> If you can, next time please try to adjust the testcases such that they
> abort if miscompiled and exit with 0 exit status otherwise, gcc testsuite
> usually doesn't check for output from the testcases.

Got it; will do.