[llvm] [AArch64] Stop reserved registers from being saved in prolog/epilog (PR #138448)

[Nuko Y. via llvm-commits]

yasuna-oribe wrote:

Does this pull request have enough approvals to be merged? If so, can anyone merge it for me?

>There wasn't any clear specification of how it should behave and using callee-save registers is at the users own risk.

@smithp35, Well, since it indeed is the users' own risk, and GCC/riscv64 llvm exhibits the behavior this PR implements, I believe this PR is a correct decision rather than leaving behavior inconsistent across targets and compilers.

https://github.com/llvm/llvm-project/pull/138448