RFR: 8336464: Force `CastX2P` to be a two-address instruction

[Fei Gao]

On Mon, 15 Jul 2024 11:28:14 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> src/hotspot/share/adlc/output_h.cpp line 1692:
>> 
>>> 1690: 
>>> 1691: #if defined(AARCH64)
>>> 1692:     // Allocate the same register for src and dst, then we can remove
>> 
>> This isn't so much AArch64 specific as specific to any machine that doesn't have separate address and data registers. x86 prefers some registers to form addresses, but for others perhaps either a target macro or a callback function in $cpu.ad.
>
> `Matcher::use_same_src_and_dest_reg_for_CastX2P` ?

Thanks for your review, @theRealAph . Updated it in the new commit.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20159#discussion_r1681101187