Flang is a Fortran language front-end designed for integration with LLVM and
the LLVM optimizer.

Flang+LLVM is a production-quality Fortran solution designed to be co-installed
and is fully interoperable with Clang C++.

Flang single-core and OpenMP performance is now on par with GNU Fortran. Flang
has implemented Fortran 2003 and has a near full implementation of OpenMP
through version 4.5 targeting multicore CPUs.