Jojo
在 2020年11月6日 +0800 AM11:18，Jeff Law <l...@redhat.com>，写道：
On 11/5/20 7:50 PM, Jim Wilson wrote:
On Thu, Nov 5, 2020 at 6:03 PM Jojo R <jiejie_r...@c-sky.com> wrote:
> > gcc/
> > * haifa-sched.c (dep_list_costs): New.
> > (rank_for_schedule): Use dep_list_costs.
>
> When you post a patch, you should explain what the patch is doing and why
> this is better than the code that was there before. It is helpful if you can
> show results that demonstrate that it is better, e.g. give a small example
> and show some scheduler or assembly output to show what it does.
>
> You should also consider that when you modify target independent code then
> you are affecting every target. This change may work well for your target,
> but does it also work for x86, arm, ppc, etc? This probably requires some
> testing to see if it works for other targets. If not, then maybe it needs to
> be conditional on a target hook.
>
> The patch does seem to make some sense though. When choosing the instruction
> that has the most dependent instructions to schedule next, you want to ignore
> the ones that have a 0 cost dependency due to a bypass.
Agreed. It looks pretty reasonable, but a bit more background would be helpful.
Ok & Thanks,
It’s fixed in patch v3.
jeff
