[PATCH] D143409: [SCEV][IndVarSimplify] Add nsw/nuw falgs to binary ops before visiting IVUsers

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

IIRC strengthenBinaryOp() is expensive, it would be great not to call it twice. (It works on double-sized SCEV expressions, so usually 128 bits, and thus takes all the slow paths).

It would be helpful to provide some more context on what the actual problem here is, i.e. in which order are we visiting instructions / performing folds in the example, and what would the right order be. I suspect it's not actually necessary to call it twice, but it's hard to say without understanding the root problem.


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  https://reviews.llvm.org/D143409/new/

https://reviews.llvm.org/D143409