[PATCH] D78932: [DSE,MSSA] Relax post-dom restriction for objs visible after return.

[Florian Hahn via Phabricator via llvm-commits]

fhahn updated this revision to Diff 265771.
fhahn marked an inline comment as done.
fhahn added a comment.

Rebased

In D78932#2047134 <https://reviews.llvm.org/D78932#2047134>, @george.burgess.iv wrote:

> Sorry for the latency :)
>
> > I would be happy to iterate on that once we have a correct version in tree (that makes balancing the patches and benchmarking a bit easier I think), but I could also try to do it up-front, if that's preferred.
>
> WFM.


Great!

> 
> 
>> I think there potentially are cases that would be handled more efficiently with the current approach (e.g. if there are a large number of memoryDefs/uses to traverse)
> 
> Agreed, though again, the set-based approach only needs to be built once whereas this one needs to happen on every query, so it all depends on how many times we fall back to this codepath, how large the function is, and how sparse the Defs/Phis in the function are.

Yep, we definitely should collect data on that. Hopefully Ii'll be able to put the alternative together in the next week or so. As said earlier, it would be easier to get the first approach in as a baseline.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D78932/new/

https://reviews.llvm.org/D78932

Files:
  llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
  llvm/test/Transforms/DeadStoreElimination/MSSA/multiblock-memintrinsics.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/multiblock-multipath.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/multiblock-simple.ll

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