[PATCH] D63618: Exploit a zero LoopExit count to eliminate loop exits

[Sanjoy Das via Phabricator via llvm-commits]

sanjoy added a comment.

> it seems like there are a lot of cases where SCEV's exit count reasoning is stronger than it's isKnownPredicate reasoning.

This is somewhat surprising.  For instance in `@test_06` I would have expected SCEV to compute the range of `%narrow.iv` to be `[INT32_MAX, INT32_MAX+1)` (using the fact that the backedge taken count is 0), and thus figure resolve the `icmp slt` to `false` by just looking at the ranges.  Any idea why that's not happening?


Repository:
  rL LLVM

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  https://reviews.llvm.org/D63618/new/

https://reviews.llvm.org/D63618