[clang] [llvm] [BPF] Add load-acquire and store-release instructions under -mcpu=v4 (PR #108636)

[via cfe-commits]

yonghong-song wrote:

@peilin-ye Thanks for trying getExtendForAtomicOps(). I just did some experiments and indeed looks like backend has to pick one default extend, sign, unsigned, or any. My previous suggestion to match atomic_load_zext_{8,16} and atomic_load_sext_{8,16} separately won't work.

So your change looks good. Once you get some kernel work in reasonable shape, this patch can land. Thanks!

https://github.com/llvm/llvm-project/pull/108636