http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53243
Richard Guenther <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2012-05-07 Ever Confirmed|0 |1 --- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-05-07 09:31:59 UTC --- How does performance look like when you do not have random distribution of comparison results but branch pedictors can do a good job? Thus, are branch pedictors not disabled by this transform, only retaining branch target buffering? Your code can probably be optimized further by recognizing that only the parameter to cb is conditional if we don't take the else branch, thus do if (!(a < 8.0)) ++o; else do vector compare, compute cb argument from result and call cb doing no branches at all. I don't see where your or the above transform would best fit into. It's straight-line code as written, still we'd need to perform some if-conversion (difficult for calls, so only pairs with the above idea) and then vectorization.