Given the existing infrastructure in LLVM side for +fp and +fp.dp,
this is more or less trivial, needing only one tiny source change and
a couple of tests.
It doesn't really matter, I guess, but we don't need a temp file and can pipe the output directly to FileCheck?
Do we also want to check that just:
doesn't enable DSP (and other non-mandatory extensions)?
This looks good to me.