[Bug tree-optimization/126906] back threader does not thread paths into unreachable edges but DOM does

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126906

Drea Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement
   Last reconfirmed|                            |2026-08-16
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #1 from Drea Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.  But I am not sure it is unreachable which is causing the issue as
non DOM threading does not handle this either:
```

  void
  foo (int b, int c)
  {
    void *x = &&lab;
    if (b)
      {
  lab:
        return;
      }
  lab2:
    if (c)
      x = &&lab2;
    goto *x;
  }
```