[llvm] [IndVarSimplify] Ensure fp values can be represented as consecutive integers (PR #166649)

[Thalia Archibald via llvm-commits]

https://github.com/thaliaarchi commented:

Looks good to me, aside from `>`/`>=`.

I've drafted an approach which computes a closed form solution for the trip count with finite floats, taking into account precision loss. But it's more complex than this and should not block this PR. I may still contribute it later.

https://github.com/llvm/llvm-project/pull/166649