[PATCH] D46162: [PowerPC] Don't transform to CTR loop if the decrement branch instr. would end up in a different loop

[Nemanja Ivanovic via Phabricator via llvm-commits]

nemanjai updated this revision to Diff 144848.
nemanjai added a comment.

Added a check for irreducible CFG within the loop being considered for transformation - thanks for the pointers @efriedma and @hfinkel.
We simply bail out of the transformation if the loop has irreducible control flow rather than analyzing said control flow. This results in a total reduction of 2 loops out of 25,432 that are transformed in a bootstrap build.


Repository:
  rL LLVM

https://reviews.llvm.org/D46162

Files:
  lib/Target/PowerPC/PPCCTRLoops.cpp
  test/CodeGen/PowerPC/no-ctr-loop-if-exit-in-nested-loop.ll

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