RFR: 8319799: Recursive lightweight locking: x86 implementation [v12]

[Axel Boldt-Christmas]

On Thu, 25 Jan 2024 13:42:39 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

>> Well if I remember correctly from my experiments with this `USE_KILL` requires a bound register. Will get a compilation error with the change `rbx_RegP` -> `rRegP`, saying something like `only bound registers can be killed`
>
> Yes, but also with TEMP?

`TEMP` does not require a bound register. It will compile but crash later in C2.
This is only based on observed behaviour:
`TEMP` cannot be specified on an Input. Will crash in register allocation with `assert(opcnt < numopnds) failed: Accessing non-existent operand`

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PR Review Comment: https://git.openjdk.org/jdk/pull/16607#discussion_r1466407833