RFR: 8347917: AArch64: Enable upper GPR registers in C1

[Andrew Haley]

On Thu, 16 Jan 2025 12:26:43 GMT, Dmitry Chuyko <dchuyko at openjdk.org> wrote:

>  r29 (fp) are declared caller-saved

How does this work for `fp`? Surely `fp` is saved as part of the entry sequence by native ABI, C1, and C2:


  0x0000fffeecf10bac:   sub             sp, sp, #0x30
  0x0000fffeecf10bb0:   stp             x29, x30, [sp, #0x20]



The great advantage of using `fp` is that caller doesn't have to save it.

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PR Comment: https://git.openjdk.org/jdk/pull/23152#issuecomment-2614496492