[PATCH] D94232: [LoopRotate] Add PrepareForLTO stage, avoid rotating with inline cands (WIP).

Sun Jan 17 13:33:37 PST 2021

fhahn added a comment.

In D94232#2500595 <https://reviews.llvm.org/D94232#2500595>, @sanwou01 wrote:

> In D94232#2498855 <https://reviews.llvm.org/D94232#2498855>, @fhahn wrote:
>
>> In D94232#2498633 <https://reviews.llvm.org/D94232#2498633>, @sanwou01 wrote:
>>
>>> On SPEC 2017 there is still a problem with omnetpp_r (runtime error), which I'll have a look at next, but is otherwise neutral on geomean with only minor wobbles (+1%, -0.5% at most) on individual benchmarks.
>>>
>>> With this having a substantial impact on performance, I'm quite keen to help get this in soon, ideally before the LLVM 12 branch, so please let me know if there is anything else I can do to help.
>>
>> Sounds good! I think the theory behind the change should mean it should be quite safe and the data so far seems encouraging; I can confirm similar improvements for `astar` on our tracking.
>>
>> It would probably good to get this in well ahead of the 12.0 branch, so it has a chance to make it through various downstream perf-tracking systems.
>
> That's great! Agreed that this could do with a little soak on main before 12 branches, which IIRC is scheduled for 26 January?

Yes, I think the only thing outstanding with respect to testing is the `omnetpp_r` failure. Can you confirm if that is caused by the patch or not?

And any review of the patch would be appreciated of course!

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