[PATCH] D121788: [AArch64] Increase MaxInterleaveFactor to 4

Dave Green via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Tue Mar 22 04:19:59 PDT 2022


dmgreen added a comment.

Do you have any performance results for changing this? I've not had much luck with trying it in the past, and it obviously can change quite a lot. It can certainly help in places, but I've found that if you turn it up too high you just end up over-unrolling loops, not getting into the fast loop body as much. It can obviously depend on the input code and loop counts tough. Perhaps it needs some better costmodelling?

I was still hoping to get D118979 <https://reviews.llvm.org/D118979> in because it should help quite a bit - and it on it's own increases the number of items processed per vector element, and this will increase it further. We have cleaned up quite a few of the places it doesn't do as well, there are just a few that have been stuck in review a while. Perhaps it makes sense to try and push that through, then re-evaluate this on top?


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https://reviews.llvm.org/D121788



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