[Bug tree-optimization/66868] [5 Regression] wrong code generated with -O3 (dead code removal?)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66868

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2015-11-18
            Summary|[5/6 Regression] wrong code |[5 Regression] wrong code
                   |generated with -O3 (dead    |generated with -O3 (dead
                   |code removal?)              |code removal?)
     Ever confirmed|0                           |1

--- Comment #12 from Richard Biener <rguenth at gcc dot gnu.org> ---
Matthias, can you bisect what makes it work on trunk?