[clang] [llvm] [AMDGPU][WIP] Extend readlane, writelane and readfirstlane intrinsic lowering for generic types (PR #89217)

[Jay Foad via llvm-commits]

jayfoad wrote:

> 1. What's the proper way to legalize f16 and bf16 for SDAG case without bitcasts ? (I would think  "fp_extend -> LaneOp -> Fptrunc" is wrong)

Bitcast to i16, anyext to i32, laneop, trunc to i16, bitcast to original type.

Why wouldn't you use bitcasts?

https://github.com/llvm/llvm-project/pull/89217