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Summary: We are incorrectly updating the LI when loop-simplify generates dedicated exit blocks for a loop. The issue is that there's an implicit assumption that the Preds passed into UpdateAnalysisInformation are reachable. However, this is not true and breaks LI by incorrectly updating the header of a loop. One such case is when we generate dedicated exits when the exit block is a landing pad (through SplitLandingPadPredecessors). There maybe other cases as well, since we do not guarantee that Preds passed in are reachable basic blocks. The added test case shows how loop-simplify breaks LI for the outer loop (and DT in turn) after we try to generate the LoopSimplifyForm. Reviewers: davide, chandlerc, sanjoy Reviewed By: davide Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D41519 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321653 91177308-0d34-0410-b5e6-96231b3b80d8