Fortran Wiki

The Flang Compiler

The Flang compiler is a Fortran compiler targeting LLVM. The new Flang Compiler project includes two active projects associated with Fortran and LLVM:

  • the currently released Flang compiler
  • the completely new F18 compiler, a new front-end which will replace the current Flang.


Flang is a Fortran language front-end designed for integration with LLVM and the LLVM optimizer. Flang has implemented Fortran 2003 and has a near full implementation of OpenMP through version 4.5 targeting multicore CPUs.


F18 is a new Fortan front-end which has been approved to become the standard Fortran compiler for LLVM and is in the process of being adopted into LLVM proper. By the beginning of 2020, F18 is expected to replace Flang as a complete implementation of Fortran 2018.

Building Flang

Instructions for building Flang can be found on the Flang wiki: