[PATCH][AArch64] Enable AES fusion with -mcpu=generic
Fri Mar 17 10:56:00 GMT 2017
On Thu, Mar 16, 2017 at 08:26:42PM -0700, Jim Wilson wrote:
> On Thu, Mar 16, 2017 at 11:01 AM, Andrew Pinski <firstname.lastname@example.org> wrote:
> > On Thu, Mar 16, 2017 at 10:22 AM, Wilco Dijkstra <Wilco.Dijkstra@arm.com> wrote:
> >> Many supported cores implement fusion of AES instructions. When fusion
> >> happens it can give a significant performance gain. If not, scheduling
> >> fusion candidates next to each other has almost no effect on performance.
> >> Due to the high benefit/low cost it makes sense to enable AES fusion with
> >> -mcpu=generic so that cores that support it always benefit. Any objections?
> No objection. I'm not currently tracking performance of -mcpu=generic
> on falkor, so I'm not very concerned about changes to the generic
> tuning structure.
Thanks for the feedback Jim, Andrew.
This patch is OK for trunk. As Richard pointed out on the branch costs
thread, if we had a bug here we'd likely have seen it by now on those
cores which do enable the fusion.
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