[PATCH] D42604: PR36032 fix assert cause by not computed SCEV PredicatedBackEdgeCount

[Evgeny Stupachenko via Phabricator via llvm-commits]

evstupac created this revision.
evstupac added reviewers: a.elovikov, silviu.baranga, dim, dorit.
Herald added a subscriber: sanjoy.

The change fix an assert fail at ScalarEvolutionExpander.cpp (generateOverflowCheck):

  const SCEV *ExitCount =                              
      SE.getPredicatedBackedgeTakenCount(AR->getLoop(), Pred); 
                                                       
  assert(ExitCount != SE.getCouldNotCompute() && "Invalid loop count"); 

(generateOverflowCheck is called only from expandWrapPredicate)

by inserting an early check on SCEV PredicateBackEdgeCount when createAddRecFromPHIWithCastsImpl


Repository:
  rL LLVM

https://reviews.llvm.org/D42604

Files:
  lib/Analysis/ScalarEvolution.cpp
  test/Transforms/LoopVectorize/pr35432.ll
  test/Transforms/LoopVectorize/pr36032.ll

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