[llvm] [AArch64] Legalize fp128 scalars as libcalls for G_FCMP (PR #98452)

[Thorsten Schütt via llvm-commits]

tschuett wrote:

> > As you are touching the legaliizer, a MIR test would be nice.
> 
> For the most part I think we should stop doing that unless there's a really special edge case involved that would be hard to reproduce. They're harder to maintain and can miss the system not working as a whole

This PR is about legalization and not stressing the system. There is quite a bit of code added to the legalizer that is not well tested. That is why I asked for a MIR file.

https://github.com/llvm/llvm-project/pull/98452