[PATCH] D101722: [SCEV] Don't require ControlsExit for gt/lt NoWrap

[Nikita Popov via Phabricator via llvm-commits]

nikic planned changes to this revision.
nikic added a comment.

Okay, I think the change is not right after all. In particular, if we have an exit count like `((1 + %len) /u 2)` that does represent the right exit count in arbitrary precision (via either exit or executed UB), but the expression for calculating the exit count itself may still overflow. If `%len` is `UINT_MAX` then the resulting exit count would be 0, while it should be `UINT_MAX/2` (which is the iteration at which UB occurs). That's clearly not right.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D101722/new/

https://reviews.llvm.org/D101722