[PATCH] D149344: [SCEV] Replace IsAvailableOnEntry with block disposition

[Nikita Popov via Phabricator via llvm-commits]

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As far as I understand, the IsAvailableOnEntry() function basically implements the same functionality as the properlyDominates() block disposition. The primary difference (apart from a weaker implementation) seems to be in this comment at the top:

  // Checks if the SCEV S is available at BB.  S is considered available at BB
  // if S can be materialized at BB without introducing a fault.

However, I don't really understand why there would be such a requirement. It's my understanding that SCEV explicitly does not care about trapping udiv instructions itself, and it's the job of SCEVExpander's isSafeToExpand() to make sure these don't get expanded if they may trap.


https://reviews.llvm.org/D149344

Files:
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/test/Analysis/ScalarEvolution/logical-operations.ll

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