[llvm] [IVDescriptors] Don't require nsz/nnan for (min|max)num. (PR #137003)

[David Green via llvm-commits]

davemgreen wrote:

Yeah - My understanding was that the behaviour of fmax in glibc is equivalent to maxnum, which is equivalent to fmaxnm. So the patch in #112852 brought the documentation in line how it always worked for AArch64/Arm, and what fmax should always have produced. It would certainly be nice for min/max reductions to vectorize without nonan, but generating 3 instructions for every fmin/fmax would be a shame too. (Hopefully some of them can detect no-snan from the generating instruction and not hit the issue, but it likely won't help everywhere).

https://github.com/llvm/llvm-project/pull/137003