Accelerated bitfield instructions: PDEP, PEXT and BEXTR?

[juj]

Wasm currently supports some bitfield instructions. It would be very interesting to have support for a more complete set: https://en.wikipedia.org/wiki/Bit_manipulation_instruction_set

In particular, PDEP, PEXT and BEXTR instructions come up every once in a while. Have these been discussed before?

[binji]

Yes, recently :smile: (see the last paragraph of the top post) : https://github.com/WebAssembly/design/issues/1388

But before that, I don't think so; this is the main list of such instructions that were discussed: https://github.com/WebAssembly/design/blob/master/FutureFeatures.md#additional-integer-operators

I think before we add them, we'd want to do some analysis to determine how they'd be implemented in various native architectures, similar to work done on SIMD instructions.