[PATCH] D123587: [SLP] Generate shuffles if we can reorder an existing node

Mon May 9 06:15:55 PDT 2022

ABataev added a comment.

In D123587#3500553 <https://reviews.llvm.org/D123587#3500553>, @dmgreen wrote:

>> No, it tries to do the same as your patch - find reused scalars in the previously build nodes and emit shuffles, if possible, instead of bunch of extracts.
>> The problem is that we need to track the dependencies between nodes, that's why it is so big.
>
> Do you think this patch is incorrect then? Or just handling a subset of D110978 <https://reviews.llvm.org/D110978>? As far as I understand it should be safe.
>
> I think this is the last puzzle piece I need, to allow vectorcombine to see shuffles as opposed to insert/extracts. What do you think of giving this patch a go in the meantime, before the more general case is handled in D110978 <https://reviews.llvm.org/D110978>?

Yes, your patch is a subset of D110978 <https://reviews.llvm.org/D110978>. It can handle scalars from different nodes.

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https://reviews.llvm.org/D123587