> Ah, that's important information I didn't have. Thank you! No problem, glad to help! To the rest of your thoughts, I certainly agree. One interesting question is why LAA didn't use DA at all. Other than that, note that LAA is quite specialized, namely for loop vectorization. Actually, it's even more specific. For innermost loop vectorization. That affects the design. It might had been easier to create this specialized tool than extending a general one (if that was a good path to follow is another topic). > But yet they are intimately related in that the kind of information you > want to know statically and dynamically is the same. I wonder what it > would take to extend DA to generate runtime checks if it can't prove > independence. Indeed, but again, IMHO unifying them is neither easy nor does it make sense. They do fundamentally the same thing but their directions are very different. So, I see two options: a) As you said > I wonder what it would take to extend DA to generate runtime checks if it can't prove independence. Personally, I see potential but neither do I know what it would take. Since this is something that I'm currently thinking of, I would be more than interested to discuss it extensively. In any case, I would strongly prefer that we don't follow the LAA path, since I don't think it has potential anyway. I think that we should try to find a way to extend it that is also based on strong theoretical foundation and maintains the high quality of code. b) Extend LAA to do static checks The question here is though: Why do that? As I said, it doesn't seem to have potential and I believe that people working on vectorizers (either LLVM's current one or external like e.g. RV and VPlan) don't do either. Tell me what you think and I'm looking forward to more people jumping in. - Stefanos ΣÏÎ¹Ï Î¤Ïί, 7 ÎÎ¿Ï Î» 2020 ÏÏÎ¹Ï 11:11 μ.μ., ο/η David Greene < david.greene at hpe.com> ÎγÏαÏε: > Stefanos Baziotis via llvm-dev <llvm-dev at lists.llvm.org> writes: > > > Their most important difference is that DA is used for compile-time / > > static checks while LAA is mainly used for generating run-time checks. > > Ah, that's important information I didn't have. Thank you! > > > Now, as for unifying them, if we mean something other than just putting > > them in the same file, I don't think it can happen. > > IMHO they're way more apart than it initially seems. > > But yet they are intimately related in that the kind of information you > want to know statically and dynamically is the same. I wonder what it > would take to extend DA to generate runtime checks if it can't prove > independence. > > The thing I fear is one or the other being enhanced to resolve more > things statically without the other getting the same improvements. Then > some passes benefit and others don't and it won't be clear why. The > same could happen with enhancement to dynamic checking (if it were added > to DA). > > -David > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20200707/4b31c73b/attachment.html>
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