[llvm] [AMDGPU] Add intrinsic for raw atomic buffer loads (PR #97707)

[Jay Foad via llvm-commits]

jayfoad wrote:

> These intrinsics prevent LICM for atomic loads.

It's not immediately obvious (to me) how it prevents it, and why it should be prevented.

https://github.com/llvm/llvm-project/pull/97707