[llvm] [AMDGPU] Remove support for no-return buffer atomic intrinsics. NFC. (PR #69326)

[Jay Foad via llvm-commits]

jayfoad wrote:

> LGTM, I see there was some change in the GISel parts, did you check if there was equivalent logic for the DAG path?

https://reviews.llvm.org/D87719 changed the definition of the buffer_atomic_fadd intrinsics to have a return value, and also updated the SDAG handling where buffer_atomic_fadd was handled separately from other buffer atomics. The difference in GISel is that all the buffer atomics are handled together, and no-one removed that "no return" handling there that became dead.

https://github.com/llvm/llvm-project/pull/69326