[PATCH] D108910: [IndVars] Break backedge and replace PHIs if loop exits on 1st iteration

[Dmitry Makogon via Phabricator via llvm-commits]

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Implement TODO in optimizeLoopExits. Now if we have proved that some loop exit is taken on 1st iteration, we make all branches in the following exiting blocks always branch to their exits and also we replace all loop header PHI nodes with the values from the loop preheader (because the backedge is never taken and the loop is in the Loop Simplify Form).


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D108910

Files:
  llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
  llvm/test/Transforms/IndVarSimplify/eliminate-backedge.ll

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