[llvm] [AArch64] Don't emit stack restore for SME ZA non-sibling tail calls (PR #224721)

[Benjamin Maxwell via llvm-commits]

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MacDue wrote:

I think you're right that the `ZAMarkerNode` check here is incorrect. It should be safe to place `AArch64ISD::INOUT_ZA_USE` before a tail call in `inout_za` callers, as in that case we won't need to place any action after the call.

The unsafe cases (which I think are already prevented in `isEligibleForTailCallOptimization()`) are:
 - a tail call in a new ZA/ZT0 function
   - We need to stop ZA before the function returns
- a tail call before with a marker other than `INOUT_ZA_USE` in a "inout" function
  - As we need to restore the ZA/ZT0 state after the call.  
 

https://github.com/llvm/llvm-project/pull/224721