[llvm] [Float2Int] Resolve FIXME: Pick the smallest legal type that fits (PR #79158)

[via llvm-commits]

alexfh wrote:

> Oddly enough, the pass itself doesn't seem to be the issue.

Sad but true: this is a usual situation, when a seemingly correct change in one pass uncovers issues in one or more of the following passes in the pipeline. This may feel like playing pick up sticks at times, but we see this regularly =(

https://github.com/llvm/llvm-project/pull/79158