[Bug lto/66752] spec2000 255.vortex performance compiled with GCC is ~20% lower than with CLANG

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66752

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-07-13
                 CC|                            |law at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
This is simply a jump-threading opportunity that is not taken (with the
complication that this threads through the loop header).  I wonder
whether the FSM thereading machiner could catch this though.