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

Andrew Haley aph at redhat.com
Fri Jan 18 18:15:37 UTC 2019

On 1/18/19 5:29 PM, Derek White wrote:

> The original code used cmpxchgptr, but it introduced too many
> unnecessary branches. So you

Me, I think.

> or Ed changed it to this code, with a (7-8 line) comment "Formerly:
> __ cmpxchgptr" etc, etc. I thought that comment didn't add much for
> all that bulk so I asked Nick to rip the comment out!
> The function now fits on one screen (of sufficient size) though.
> Getting cmpxchgptr to work without the extra branches would be a
> better solution if someone has any thoughts in that direction.

There aren't any extra branches if you use MacroAssembler::cmpxchg.

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