With https://github.com/llvm/llvm-project/pull/112852, we claimed that
llvm.minnum and llvm.maxnum should treat +0.0>-0.0, while libc doesn't
require fmin(3)/fmax(3) for it.
To make llvm.minnum/llvm.maxnum easy to use, we define the builtin
functions for them, include
__builtin_elementwise_minnum
__builtin_elementwise_maxnum
All of them support _Float16, __bf16, float, double, long double.