[PATCH] D78455: [Scalarizer] Fix a non-deterministic scatter order problem

[Bjorn Pettersson via Phabricator via llvm-commits]

bjope added a comment.

In D78455#1991828 <https://reviews.llvm.org/D78455#1991828>, @foad wrote:

> LGTM.
>
> Out of curiosity, why are you running the scalarizer? I thought most targets didn't use it.


We still use the scalarizer downstream, partly due to historical reasons. Nowadays I don't think we depend heavily on the scalarize (SelectionDAG will manage to do the business), but last time I tried to disable it I noticed some regressions. If I remember correctly it was due to some pre-isel-rewrites not triggering the same way when delaying the scalarization until isel (I think it was something that wasn't hoisted out of a loop so the penalty could not be ignored).

Thanks for the review!


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https://reviews.llvm.org/D78455