[PATCH] D93423: [GlobalISel] Use slot indexes to speed up huge block compile time

[Aditya Nandakumar via Phabricator via llvm-commits]

aditya_nandakumar added a comment.

In D93423#2459018 <https://reviews.llvm.org/D93423#2459018>, @aemerson wrote:

> In D93423#2459004 <https://reviews.llvm.org/D93423#2459004>, @aditya_nandakumar wrote:
>
>> If slot indexes are preserved and used in other passes that use CSE, do you think the compile time impact is amortized/minimized?
>
> It's possible it would help a bit. I think the localizer may also benefit from this. I don't see it making a big difference either way though in most code.

In our out of tree backend, CSE is used and preserved for 6 passes in total. I suspect if slot indexes are also preserved, the overhead might not be too much. Hence I was curious if you actually collected some numbers. If only legalizer is being looked at for compile time impact, we're not really evaluating the compile time savings to be had in other passes (assuming amortized cost of slot index) right?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D93423/new/

https://reviews.llvm.org/D93423