On July 25, 2016 8:01:17 PM GMT+02:00, Jeff Law <l...@redhat.com> wrote: >On 07/22/2016 05:36 AM, Richard Biener wrote: >> The thing that needs work I think is re-running of if-conversion. >I wonder if we could revamp if-conversion to work on a subset of the >CFG? I can see that potentially being useful in other contexts. >Would >that work for you Richi?
Well, you need to make it not need post-dominators or preserve them (or compute "post-dominators" on SESE regions). What doesn't work with the idea to clone the epilogue using __built-in_vectorized() For the if- vs. Not if-converted loop? Richard. >We've already got Bin doing that for DOM... > > >> Also I don't like at >> all that we have many variants of vectorizing but somehow the >decision which one >> to choose is rather unclear. The way the epilogue vectorization code >> is hooked in >> is rather awkward and bound to be a maintainance burden (well, maybe >a >> small one). >I think it's going to be a small one. I suspect that we really need >another architecture with masking capabilities to really be able to see > >how the costing models ought to work and bring sanity to that decision. > >> >> And last, I double there is a case for a masked vectorized loop - I >can bet that >> doing a non-masked vectorized loop plus a masked epilogue (with no >iteration >> then!) will be always faster unless you hit the window of very few >iterations >> (or optimizing for size - in which case vectorizing is questionable >on >> its own and >> disabled IIRC). >Ilya, does this case make a noticeable difference with the ICC >implementation? > >Jeff
