RFR: [11u] 8217368: AArch64: C2 recursive stack locking optimisation not triggered

[Andrew Haley]

On 8/23/19 10:52 AM, Andrew Dinn wrote:
>> The original webrev.0 contains a more minimal patch, with just the logic
>> change. The final patch also included some refactoring to use
>> MacroAssembler::cmpxchg which doesn't affect the behaviour but does
>> improve the readability significantly.
>>
>> http://cr.openjdk.java.net/~ngasson/8217368/webrev.0/src/hotspot/cpu/aarch64/aarch64.ad.udiff.html
>
> Indeed. MacroAssembler::cmpxchg did not exist when the encoding rule was
> first written (at least not in its current variant with all the flag
> arguments that determine the flavour of compare and update to be used).
> Switching to use it is for clarity and simplicity rater than to change
> function.

Mmm, but it greatly obfuscates this particular patch. I know that it's
extra work, but if you can submit a separate patch to use
MacroAssembler::cmpxchg and then the actual bug fix I'll approve them
both.

-- 
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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