[PATCH] D45754: [PM/LoopUnswitch] Detect irreducible control flow within loops and skip unswitching non-trivial edges.

[Chandler Carruth via Phabricator via llvm-commits]

chandlerc created this revision.
chandlerc added reviewers: sanjoy, fedor.sergeev.
Herald added subscribers: hiraditya, mcrosier.

This fixes the bug pointed out in review with non-trivial unswitching.

This also provides a basis that should make it pretty easy to finish
fleshing out a routine to scan an entire function body for irreducible
control flow, but this patch remains minimal for disabling loop
unswitch.


Repository:
  rL LLVM

https://reviews.llvm.org/D45754

Files:
  llvm/include/llvm/Analysis/LoopInfo.h
  llvm/include/llvm/Analysis/LoopInfoImpl.h
  llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
  llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch.ll

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