[camel-cdr]

> +1 to dzaima's mention of vrgather. The lack of fixed-pattern shuffle instructions in RVV is absolutely a wrong-instruction issue.

What others would you want? Something like vzip1/2 would make sense, but that isn't much of an permutation, since the input elements are exctly next to the output elements.

[janwas]

Going through Highway's set of shuffle ops:

64-bit OddEven/Reverse2/ConcatOdd/ConcatEven, OddEvenBlocks, SwapAdjacentBlocks, 8-bit Reverse, CombineShiftRightBytes, TableLookupBytesOr0 (=PSHUFB) and Broadcast especially for 8-bit, TwoTablesLookupLanes, InsertBlock, InterleaveLower/InterleaveUpper (=vzip1/2).

All of these are considerably more expensive on RVV. SVE has a nice set, despite also being VL-agnostic.