[api]

Given that all these are ARX cores, I wonder if a fused ARX instruction could cover a wide range of them?

[brandmeyer]

ARMv8.2 has rotate-and-xor and xor-and-rotate so that the (extremely cheap) xor can be saved.

[SAI_Peregrinus]

Probably. With a barrel shifter easily. Barrel shifters are a bit slower than wired shifts though, so for ultimate speed you'd end up with hardware shift amounts.

[api]

The advantage would be a single instruction that implemented the core of a wide range of things including BLAKE2, BLAKE3, Salsa, ChaCha, Speck, and more.