[PATCH] D59211: [LSR] Check for signed overflow in NarrowSearchSpaceByDetectingSupersets.

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

It looks like LSR doesn't deal with this sort of issue consistently... some places we try to overflow-check arithmetic on the offset, and others we use wrapping arithmetic.

What should happen, really, is that each formula includes a bitwidth, and all arithmetic involving that formula use arithmetic that wraps at that bitwidth (like an APInt).  Otherwise it's not really clear what the computation actually means.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D59211/new/

https://reviews.llvm.org/D59211