This is the same LLVM Fortran project as discussed two years ago in the thread you linked. Two years ago was just an announcement, now they are publishing some open source code (which might or might not actually work, for some definition of "work", I haven't tried it).

So the backstory is that Nvidia bought PGI, a company which produced a C/C++/Fortran compiler suite which was moderately commonly used in HPC. Then they took the Fortran frontend from the PGI suite and bolted it to LLVM and open sourced it as flang.