[clang] [llvm] Clang: Add nsz to llvm.minnum and llvm.maxnum emitted from fmin and fmax (PR #113133)

[Matt Arsenault via cfe-commits]

arsenm wrote:

> I'm not sure this is correct. At least the way alive models the flag, I believe this would also allow returning -0.0 even if both operands are 0.0, which is not a legal outcome.

That sounds like a bad modeling. It shouldn't permit synthesizing a -0 out of nowhere 

https://github.com/llvm/llvm-project/pull/113133