[aarch64-port-dev ] RFR: 8217368: AArch64: C2 recursive stack locking optimisation not triggered

Andrew Haley aph at redhat.com
Fri Jan 18 14:56:07 UTC 2019


On 1/18/19 9:52 AM, Nick Gasson (Arm Technology China) wrote:

> On 18/01/2019 17:36, Andrew Haley wrote:
>> The patch looks good. However, I don't understand why we aren't using
>> MacroAssembler::cmpxchgptr here. It looks like we should be, and you'd
>> end up with a less complex result.
> It's not exactly the same though: MacroAssembler::cmpxchgptr adds a "dmb 
> ish" to the failure path which I don't think is required here.

Oh, sorry. I should have said MacroAssembler::cmpxchg, with a
br.eq(cont) afterward.

>>> * Does anyone know what the comment "// Load Compare Value application
>>> register." means? It's present in the PPC and S390 ports too.
>> Probably no-one can remember. We'll have inherited it from x86.
> Let's delete it then.


Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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