[LV][NFCI]Use integer for cost/trip count calculations instead of double, fix possible UB.

Using fp type in the compiler is not the best idea, here it used with
the comparison for equal to 0 and may cause undefined behavior in some
cases.

Reviewers: fhahn

Reviewed By: fhahn

Pull Request: https://github.com/llvm/llvm-project/pull/87241