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 > <mailto: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. jeff
