[PATCH] D47899: [SCEV] Estimate upper bound of trip count from predicated backedge count

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

In case it wasn't clear, getSmallConstantMaxTripCount must be conservatively correct: we use it to unroll loops with an unknown trip count, so we'll miscompile if the trip count at runtime is larger.  We could add a separate method for an "estimated" maximum trip count, using a heuristic like this, if it would be useful for the vectorizer.


Repository:
  rL LLVM

https://reviews.llvm.org/D47899