[PATCH] D46706: [PM/LoopUnswitch] Support partial trivial unswitching.

[Sanjoy Das via Phabricator via llvm-commits]

sanjoy accepted this revision.
sanjoy added a comment.
This revision is now accepted and ready to land.

This lgtm.

Have you considered making full unswitching a special case for partial unswitching?  It seems like we could "partially unswitch" `br %loop_invariant, label %t, label %f` into `br true/false, label %t, label %f` and have a beefed up LoopSimplifyCFG clean this up?



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Comment at: llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp:84
+  SmallVector<Value *, 4> Invariants;
+
+  // Build a worklist and recurse through operators collecting invariants.
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Assert that `Root` is loop invariant?  That justifies why we're not adding it to `Invariants`.


Repository:
  rL LLVM

https://reviews.llvm.org/D46706