[llvm] [FastIsel] Get the right register type for call instruction (PR #164565)

[Phoebe Wang via llvm-commits]

phoebewang wrote:

> > Does this solve #134222?
> 
> Solve the same issue of https://godbolt.org/z/15K5Pb7GG which generate incorrect instruction "call __truncsfbf2 at PLT". The callee return bf16 value through xmm0, so don't need to convert from f32 to bf16.

Great! I spent some time on it, but didn't find a concise solution.

https://github.com/llvm/llvm-project/pull/164565