[PATCH] D132190: [AArch64][GlobalISel] Legalize G_SHUFFLE_VECTOR with different lengths

[Amara Emerson via Phabricator via llvm-commits]

aemerson added a comment.

In D132190#3763576 <https://reviews.llvm.org/D132190#3763576>, @aemerson wrote:

> In D132190#3758013 <https://reviews.llvm.org/D132190#3758013>, @foad wrote:
>
>>> this seems to be something that needs to be done generically for all targets
>>
>> It seems like something that could be available in LegalizerHelper for targets that want to use it. I don't see why it is necessarily required for **all** targets.
>
> In that case I wonder if this could be done as a `Lower` action as an intermediate step before the legalizer tries to scalarize the shuffle.

But on second thought, doing so would probably make the target's legalizer rules more complex since we'd have to check for non-canonical forms with the legalizer predicates.


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https://reviews.llvm.org/D132190