[PATCH] D105216: [ScalarEvolution] Fix overflow in computeBECount.

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

The general formula for the backedge-taken count can be written, in arbitrary-precision arithmetic, as something like `floor(max(End - Start + Stride - 1, 0) / Stride)`, I think.  We could define a function to compute that, I guess, separate from howManyLessThans, and optimize based on that.

Granted, that's basically just taking this patch, and shoving the code into a different function.  But it might be easier to reason about future changes.


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https://reviews.llvm.org/D105216