RFR: 8319799: Recursive lightweight locking: x86 implementation [v13]

[Axel Boldt-Christmas]

On Thu, 25 Jan 2024 13:23:04 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

>> Axel Boldt-Christmas has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - Update variable names in ad files
>>  - Preload markWord unconditionally
>
> src/hotspot/cpu/x86/x86_32.ad line 13807:
> 
>> 13805:   predicate(LockingMode == LM_LIGHTWEIGHT);
>> 13806:   match(Set cr (FastLock object box));
>> 13807:   effect(TEMP eax_reg, TEMP tmp, USE_KILL box, TEMP thread);
> 
> Consider changing USE_KILL box to TEMP box. Same overall considerations (long-term, in a follow-up) as in aarch64.

An input cannot be `TEMP` so must change the required input nodes for FastLockNode and FastUnlockNode.

Planned this as a followup RFE, would also change the `eBXRegP` / `rbx_RegP ` constraint to `eRegP` and `rRegP`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16607#discussion_r1466402815