Hi,

These operations were added to Fortran 2018, and correspond to well-defined IEEE comparison operations, with defined signaling semantics for NaNs. All are implemented in terms of GCC expressions and built-ins, with no library support needed.

Bootstrapped and regtested on x86_64-linux, both 32- and 64-bit. Depends on a patch currently under review for the middle-end (https://gcc.gnu.org/pipermail/gcc-patches/2022-September/600840.html).

OK to commit?
FX