[llvm] [AMDGPU][True16][MC] Support v_swap_b16. (PR #100442)

[Jay Foad via llvm-commits]

jayfoad wrote:

Can you please split this into one patch which just adds MC (assembler/disassembler) support and tests, and then a second patch which adds CodeGen support and tests?

https://github.com/llvm/llvm-project/pull/100442