RFR: 8324123: aarch64: fix prfm literal encoding in assembler [v4]

[Emanuel Peter]

On Thu, 25 Jan 2024 11:54:11 GMT, Wang Zhuo <wzhuo at openjdk.org> wrote:

>> src/hotspot/cpu/aarch64/assembler_aarch64.cpp line 192:
>> 
>>> 190: // This encoding is similar (but not quite identical) to the encoding used
>>> 191: // by literal ld/st. see JDK-8324123.
>>> 192: // FIXME: PRFM should not be used with writeback modes, but the assembler
>> 
>> FIXME: is it ok to leave this in the code?
>> I think we prefer filed RFE's to comments in the code that nobody will ever look at again.
>> You can put the RFE number in the code though.
>
> Thanks. The FIXME was there because PRFM did not support pre/post indexing and we had no check for that. 
> Some guarantee checks were added and FIXME was removed.
> Please check the last 3 patches.

Thanks @sandlerwang !

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PR Review Comment: https://git.openjdk.org/jdk/pull/17482#discussion_r1466264412