Hi Jaro, Thanks for your reply.
> On Sep 10, 2018, at 9:28 AM, jarin via v8-dev <[email protected]> wrote: > > > > On Sunday, September 9, 2018 at 4:50:38 AM UTC+2, Bekket McClane wrote: > Hi, > > I'm currently studying some graph reduction passes. > It seems that LoopPeeling is only used when certain flag is turn on. I'm > curious about the status and usage of this pass > > The pass is on by default. > > > Also, though the algorithm does the eligibility check, it doesn't do any > suitability check - it just peels the first iteration anyway. To me, this > doesn't make much sense, since force peeling the first iteration not always > give you performance improvement. Is there any specific reasons for doing > this? > > Right, we just have not done the work of figuring out a suitable heuristic to > enable loop peeling. We had some rough ideas, but we have never tried them. > Do you know of any good heuristics for loop peeling (or literature where it > is discussed)? Interesting. I used to work on LLVM, which is more like a ’traditional’ compiler. So the first thing comes to my mind when talking about loop peeling would be vectorizations. However, I don’t think Turbofan would generate machine codes that leverages vector instructions (maybe I’m wrong). And actually, to me, I’m more interested in seeing native vector instructions support since it would enable a bunch of loop optimizations that are not exist in current V8. In addition to vectorization, LLVM would peel out some PHIs when it knows they would become loop invariant after some iterations. Hope this information helps Bests, Bekket > > Cheers, Jaro > > > Thank you. > > Bekket > > -- > -- > v8-dev mailing list > [email protected] > http://groups.google.com/group/v8-dev <http://groups.google.com/group/v8-dev> > --- > You received this message because you are subscribed to a topic in the Google > Groups "v8-dev" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/v8-dev/UOrrj3d94Ww/unsubscribe > <https://groups.google.com/d/topic/v8-dev/UOrrj3d94Ww/unsubscribe>. > To unsubscribe from this group and all its topics, send an email to > [email protected] > <mailto:[email protected]>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. -- -- v8-dev mailing list [email protected] http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
