[llvm] [AArch64][SME] Implement the SME ABI (ZA state management) in Machine IR (PR #149062)

[Benjamin Maxwell via llvm-commits]

MacDue wrote:

> This is mainly a high level structural review, because I've yet to properly check the finer details of the emit... functions (although I'm guessing they're mostly taken from the existing implementation?).

`emitAllocateLazySaveBuffer` is based on the existing `EmitAllocateZABuffer`.  The others are based on what existing IR or SelectionDAG lowerings did, but ported to MIR.

> What I've seen does look very nice.

:smile: 

https://github.com/llvm/llvm-project/pull/149062