[llvm] [CodeGen] Use 128bits for LaneBitmask. (PR #111157)

[Jay Foad via llvm-commits]

jayfoad wrote:

FYI I once added a similar 128-bit-int-like class here: https://github.com/llvm/llvm-project/blob/bf488ed6e1fbe4c494a1dc0dd199a3d03405784e/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.h#L37

Maybe one day it could migrate into ADT, if there is enough commonality.

https://github.com/llvm/llvm-project/pull/111157