[PATCH] D144274: [InstCombine] use loop info when running the pass after loop vectorization

Mon Mar 13 01:51:55 PDT 2023

david-arm added a comment.

In D144274#4186897 <https://reviews.llvm.org/D144274#4186897>, @spatel wrote:

> In D144274#4186866 <https://reviews.llvm.org/D144274#4186866>, @nikic wrote:
>
>> Hm, it looks like this ended up causing non-trivial codegen changes: https://llvm-compile-time-tracker.com/compare.php?from=772aa05452f8ff90a47168e6801cda2acb5a1873&to=43ae4b62b2671cf73e691c0b53324cd39405cd51&stat=size-text So we're not preserving previous behavior in some significant way(s).
>
> Thanks - I reverted with 43ae4b62b267 <https://reviews.llvm.org/rG43ae4b62b2671cf73e691c0b53324cd39405cd51>.
> It's unlikely that I will be able to investigate those diffs in the near term, so hopefully someone else can commandeer/edit this patch and update D144045 <https://reviews.llvm.org/D144045>.

Hi @sanjay, thanks for landing the patch anyway!

@nikic, do you still believe this patch is the correct way forward in order to enable D144045 <https://reviews.llvm.org/D144045>? It sounds like your main concern is that we're probably missing some other places where we need to set UseLoopInfo? It would be to make progress on D144045 <https://reviews.llvm.org/D144045>, or indeed any approach that fixes the fdiv sinking issue!

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https://reviews.llvm.org/D144274