[llvm-dev] [RFC] Extending shufflevector for vscale vectors (SVE etc.)

[Richard Sandiford via llvm-dev]

Eli Friedman via llvm-dev <llvm-dev at lists.llvm.org> writes:
> [...]
> We can add more shuffles to the list.  There are a few SVE shuffle
> instructions which are not equivalent to any of the basic operations
> I've listed: ext and trn.

I realise this wasn't supposed to be an exhaustive list, but FWIW:
revb, revh and revw are also useful for reversing each sequence
of N elements (as opposed to reversing the whole vector).

Thanks,
Richard

> And it's possible to construct other shuffles out of sequences of
> multiple instructions.  (Some of the additional shuffles we could
> specify would require an integer parameter, or an integer parameter
> list; it should be possible to support that without any major changes
> to the proposal.)
>
> -Eli
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