[PATCH] D32201: [RALLOC] Increase CSR cost in RegAllocGreedy to favour splitting over CSR first use

Mon Aug 12 09:34:20 PDT 2019

wmi added a comment.

In D32201#1620644 <https://reviews.llvm.org/D32201#1620644>, @wuzish wrote:

> Should this good patch be rebased and continued to move on? @wmi 
>  it'd be better to move on this work because D27366 <https://reviews.llvm.org/D27366> is abandoned and D34608 <https://reviews.llvm.org/D34608> is not updated for a long time, and those 3 patches are all trying to fix same issue and not landed successfully.
>  It would be great If it can land.

Thanks for bringing it to attention again.

I still think the patch will be very helpful for some cases especially when dynamic profile information is available (when FDO/SampleFDO is used). It is tricky if there is only static profile available. I will reevaluate the patch and see how it works if I change the patch to be functioning only when we have dynamic profile. If you are more interesting on the case when dynamic profile is not available -- i.e., try to make the patch more general, feel free to take over it and I will be happy to join discussion and review.

Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D32201/new/

https://reviews.llvm.org/D32201