The HEX float on z/OS does not have infinity nor NaN. In addition, the
limits are smaller before the overflow occurs in mathematical
calculations. This PR accounts for this.
FYI, this LIT test was recently added in PR
[89982](https://github.com/llvm/llvm-project/pull/89982)
Implementing the Hermite polynomials which are part of C++17's
mathematical special functions. The goal is to get early feedback which
will make implementing the other functions easier. Integration of
functions in chunks (e.g. `std::hermite` at first, then `std::laguerre`,
etc.) might make sense as well (also see note on boost.math below).
I started out from this abandoned merge request:
https://reviews.llvm.org/D58876 .
The C++23 standard defines them in-terms of `/* floating-point type */`
arguments. I have not looked into that.
Note, there is still an ongoing discussion on discourse whether
importing boost.math is an option.
