[jdk21u-dev] RFR: 8320379: C2: Sort spilling/unspilling sequence for better ld/st merging into ldp/stp on AArch64

[Andrew Haley]

On Tue, 11 Jun 2024 18:25:52 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> > > In other words, on this trivial workload, this saves us ~0.15% of code cache. If this holds for larger apps, this amounts at about 192K for 128M code cache. This looks like a benefit enough for the cost of this backport :) It would, of course, impact even higher when we miss `ldp` optimization somewhere near heavy spills on a hot path.
> > 
> > So this is the kind of argument that should have been made.
> 
> True. Are you satisfied with it?

Yes, I think so. It's remarkably effective for such a simple optimization.

-------------

PR Comment: https://git.openjdk.org/jdk21u-dev/pull/665#issuecomment-2162500554