[PATCH] D92385: [ARM] Add a pass that re-arranges blocks when there is a backwards WLS branch

[Sam Parker via Phabricator via llvm-commits]

samparker added inline comments.


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Comment at: llvm/lib/Target/ARM/ARMLowOverheadLoopBlockPlacement.cpp:45
+                        << BB.getName() << " to " << Target->getName() << "\n");
+      // Make sure that moving this block would not cause a WLS in the target BB
+      // to branch backwards
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Thanks for inlining this, I can now read and understand it better. I'm wondering whether it would it be simpler to move BB instead of Target? Or at least we should try to figure out which one is best to move as ideally we want the WhileLoopStart parent block to fallthrough to the preheader without the need for a branch. If the most of the preheaders already fallthrough to the loop header, then I think it makes sense to move the WhileLoopStart block to just before the preheader.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D92385/new/

https://reviews.llvm.org/D92385