[PATCH] D40146: [JumpThreading] Preservation of DT and LVI across the pass

[Florian Hahn via Phabricator via llvm-commits]

fhahn added a comment.

In https://reviews.llvm.org/D40146#1042130, @dberlin wrote:

> +1. Real time updating in the presence of how  JT operates right now is too
>  costly.
>  The lazy analysis it uses require DT be updated at all times, forever
>  (instead of say, once an iteration).
>  There is no way to update the domtree 100000 times a pass and make it fast
>  :)
>  What we should be targeting is O(10)-O(100) updates.


Thanks for the feedback. As DuplicateInstructionsInSplitBetween does not take a dominator tree as arugment, it might be better to pass in a DeferredDominance object to update the DT to start with and do the update incrementally.  I am just trying to figure out the best way going forward, as I need to update the DT after DuplicateInstructionsInSplitBetween in https://reviews.llvm.org/D43173 too :)


Repository:
  rL LLVM

https://reviews.llvm.org/D40146