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

[Dmitry Chuyko]

On Sun, 26 Jan 2025 16:34:45 GMT, Andrew Haley <aph at openjdk.org> wrote:

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

Thanks, I missed it: MacroAssembler::build_frame()/remove_frame(). I excluded r29 from caller-saved regs and from oop map. Now it's like:

r19-r26 are declared as caller-saved and enabled, r27 (rheapbase) is declared caller-saved, r27 (rheapbase) and r29 (fp) are enabled conditionally similar to C2.

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PR Comment: https://git.openjdk.org/jdk/pull/23152#issuecomment-2621475897