[llvm] [InstCombine] Don't convert a compare+select into a minnum/maxnum intrinsic that can't be lowered back to a compare+select (PR #177821)

[Ilya Popov via llvm-commits]

ilyapopov wrote:

> This also seems to regress basic clamp code https://godbolt.org/z/Mz5bzxoqz.

Interestingly, on `x86-64` the code is much better without `-ffast-math`. 

https://github.com/llvm/llvm-project/pull/177821