[clang] [llvm] [IR] Add fast-math support to {u,s}itofp (PR #198470)

[Nikita Popov via cfe-commits]

nikic wrote:

I think the assumption may be that for uitofp nsz applies to the return value (contrary to our general definition) so that a 0.0 result can non-deterministically flip to -0.0?

I agree that having it on fptoui would make more sense for this transform, and match normal nsz semantics.

https://github.com/llvm/llvm-project/pull/198470