[PATCH] D79234: [ValueTracking] Fix computeKnownBits() with bitwidth-changing ptrtoint

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

Historically, we allowed IR without a datalayout, so we didn't actually know what the pointer width would be when the IR was eventually compiled.  Given that, allowing arbitrary casts was the least-bad alternative: otherwise, we wouldn't be able to verify a module.

Now that datalayout is required, we could maybe restrict the legal ptrtoint casts?  Not sure what we would do about ptrtoint constant expressions; constant expressions that don't reference globals aren't associated with a particular module.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D79234/new/

https://reviews.llvm.org/D79234