[llvm] [X86] Faster truncf and roundf on x86 SSE2 (PR #226513)

[Ralf Jung via llvm-commits]

RalfJung wrote:

(LangRef is not the right document I think, ISel nodes have their own semantics. But in this case I assume they are the same, and anyway as you say it does not matter any more.)

https://github.com/llvm/llvm-project/pull/226513