[llvm] [SCEV] Apply loop guards to End in computeMaxBECountForLT (PR #116187)

[Nikita Popov via llvm-commits]

nikic wrote:

> Possibly using pre-computed guards in howManyLessThans would help, though I'm not sure (the existing guard uses are conditional).

Or going one level higher, we could pre-compute the guards for all exit count calculation for a given loop, which would be beneficial for multi-exit loops. Possibly this needs to be lazy though for the cases where we don't need the guards at all.

https://github.com/llvm/llvm-project/pull/116187