[llvm] [SPIRV] Enable `bfloat16` arithmetic (PR #166031)

[Alex Voicu via llvm-commits]

https://github.com/AlexVlx commented:

> NIT: Can we add a helper `canHandleBF16ForTarget()` that does the `MF->getTarget().getTargetTriple().isSPIRV()` check?
> 
> Adding a hook in `TargetMachine` would be ideal but it'd be an overkill. 

We can; I'm actually not entirely certain that the check isn't vestigial at this point / if it should happen in IRTranslator at all rather than something that is left to the instruction selection / the target (the LTT issue that is mentioned in a TODO elsewhere might've been solved). Perhaps someone who is more informed can advise?

https://github.com/llvm/llvm-project/pull/166031