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

[via llvm-commits]

AtariDreams wrote:

> reverted, please create a new PR to reland this patch with the fix once you've investigated

So I compiled this at head using x86-64 as a target and I am not getting the error.

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