[Bug middle-end/47298] -O3 destroys beautifully vectorized code obtained at -O2

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47298

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1

--- Comment #5 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-06-29 
15:01:28 UTC ---
The issue is we completely unroll the innermost loop at -O3 -funroll-loops.
We then vectorize the outer loop but have to peel for alignment (and are not
good at seeing we run at most once there).