Hi,

These functions were added in Fortran 2018: https://gcc.gnu.org/wiki/Fortran2018Status
When it comes to floating-point and IEEE compliance, gfortran fully implements the 2003 and 2008 standards. In a series of patch, as time permits, I would like to add all Fortran 2018 features before the GCC 13 release process begins.

Regarding this patch, the functions are added to the IEEE_ARITHMETIC module, but are entirely expanded in the front-end, using GCC built-ins. They will benefit fully from middle-end optimisation where relevant, and on many targets FMA will reduce to a single instruction (as expected).

Regression-tested on x86_64-pc-linux-gnu. OK to commit?

FX