[PATCH] D109958: [LoopFlatten] Enable it by default

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks added a comment.

In D109958#3055878 <https://reviews.llvm.org/D109958#3055878>, @alanphipps wrote:

>> There are already a good number of divergences between the two pass managers, I don't see the harm in keeping the LPM pipeline the same. Do you specifically care about this pass?
>
> Yes, we asked about loop flattening a year ago along with a jump threading improvement in the context of improving the Coremark, and @SjoerdMeijer indicated that there was a pending code review.  I can appreciate that there are already divergences between the two pass managers.  If there is a possibility of regression on the LPM in this case, then I can understand not enabling it by default.  We can explore enabling it downstream, but any other information about impact to the LPM would be helpful and appreciated.  Thanks!

We could make the flag only affect the LPM and forcibly enable loop flatten in the NPM without a flag to turn it off. That way it'd be easier for downstream users to evaluate it with the LPM.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D109958/new/

https://reviews.llvm.org/D109958