[Bug tree-optimization/52272] [4.7 regression] Performance regresswion of 410.bwaves on x86.

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52272

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
           Keywords|                            |missed-optimization
   Last reconfirmed|                            |2012-02-16
          Component|regression                  |tree-optimization
         AssignedTo|unassigned at gcc dot       |rguenth at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1
   Target Milestone|---                         |4.7.0

--- Comment #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-02-16 
10:39:34 UTC ---
I didn't see the regression on a SandyBridge machine with -Ofast -funroll-loops
-fpeel-loops -march=native [-flto].  But I can see the regression on an
AMD Bulldozer machine.

I will have a look.  Note that the patch was to fix a wrong-code issue, so
we may have to live with the performance regression.