Hi, Have you some news about dfg optimisations? what are you planing, what have you now or what is your current work ?
Currently we do not have either LICM, or loop peeling, or GCSE. We do have > a patch that implements LICM, but we are letting it simmer for now because > under the current DFG IR, it is somewhat of a complicated beast. My main > concern is just bug tail, due to the various stunts that the current LICM > patch has to do to fool the DFG into moving code between basic blocks. > > We're fixing that by steadily moving the DFG IR towards SSA. Once we > finish that, I think we'll implement either LICM or peeling+GCSE based on > whatever appears to be the simplest. We already know that LICM is a pure > performance win; but on the other hand, GCSE is likely to be more generic. > I tend to think that extending our current CSE framework to support some > maximally-profitable subset of GCSE will not be terribly difficult. > > We don't currently have PRE. It's not on my short list of optimizations to > implement. > > But if we wanted to go down that route, it might be interesting to > consider something like Van Drunen's GVN-PRE [1]. I have already been > thinking about implementing GVN; maybe just going straight for GVN-PRE > would turn out to be easy enough. But it goes without saying that GVN alone > is a dead-simple optimization compared to Van Drunen's work, and, even > according to his performance results, PRE is a *tiny* win over simpler > redundancy elimination optimizations. > > -Filip > > [1] ftp://ftp.cs.purdue.edu/pub/hosking/papers/a-ssapre.pdf > > > > On Mar 25, 2012, at 4:59 PM, Nare Karapetyan wrote: > > > HI! > > > > There is a discussion about LICM implementation in DFG in one of > previous posts. > > There it was said that the developers had not decided yet which > optimization to do: LICM or loop peeling with global CSE. > > So is there any progress in this direction? > > > > > > And about CSE, does it include the partial redundancy elimination (PRE)? > > > > > > -- > > > > > > _______________________________________________ > > webkit-dev mailing list > > webkit-dev@lists.webkit.org > > http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.webkit.org/pipermail/webkit-dev/attachments/20120325/a57e47fa/attachment-0001.html > > > > ------------------------------ > > _______________________________________________ > webkit-dev mailing list > webkit-dev@lists.webkit.org > http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev > > > End of webkit-dev Digest, Vol 82, Issue 38 > ****************************************** >
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