[Bug tree-optimization/78559] New: [7 Regression] wrong code due to tree if-conversion?

["ktkachov at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78559

            Bug ID: 78559
           Summary: [7 Regression] wrong code due to tree if-conversion?
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ktkachov at gcc dot gnu.org
  Target Milestone: ---

The testcase:
int g = 20;
int d = 0;

short
fn2 (int p1, int p2)
{
  return p2 >= 2 || 5 >> p2 ? p1 : p1 << p2;
}

int
main ()
{
  int result = 0;
lbl_2582:
  if (g)
    {
      for (int c = -3; c; c++)
        result = fn2 (1, g);
    }
  else
    {
      for (int i = 0; i < 2; i += 2)
        if (d)
          goto lbl_2582;
    }
  if (result != 1)
    __builtin_abort ();
  return 0;
}


used to (erroneously) abort on aarch64-none-linux-gnu with -O3 after r235808
but stopped aborting with r242550. It still passes after the fix r242689 but
I'm not sure if the bug has just gone latent.

To reproduce on aarch64 you'll have to revert r242689 and r242550.