[PATCH] D47408: [PM/LoopUnswitch] When using the new SimpleLoopUnswitch pass, schedule loop-cleanup passes at the beginning of the loop pass pipeline, and re-enqueue loops after even trivial unswitching.

[Chandler Carruth via Phabricator via llvm-commits]

chandlerc added a comment.

Thanks for review all! (Waiting on the patch before this in order to land this one.)



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Comment at: llvm/lib/Passes/PassBuilder.cpp:396-397
   // `SimplifyCFGPass` and `InstCombinePass` are used. We have
   // `LoopSimplifyCFGPass` which isn't yet powerful enough, and the closest to
   // the other we have is `LoopInstSimplify`.
   LoopPassManager LPM1(DebugLogging), LPM2(DebugLogging);
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fedor.sergeev wrote:
> Time to update the comment? :)
No? I think this is still true. We still break it into two pipelines. I don't think LoopSimplifyCFG has had enough of SimplifyCFG ported to it to make it effective to re-merge the loop pipelines (yet).


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Comment at: llvm/lib/Transforms/IPO/PassManagerBuilder.cpp:340
+  // Begin the loop pass pipeline.
   // Rotate Loop - disable header duplication at -Oz
+  if (EnableSimpleLoopUnswitch) {
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dmgreen wrote:
> Should this comment be moved down next to the loop rotate pass?
I think I even intended to do that. Not sure how this ended up this way. Anyways, well spotted. Fixed. =D


Repository:
  rL LLVM

https://reviews.llvm.org/D47408