Clone this repo:


  1. 55f50f1 Revert "[flang] Fix execute_command_line cmdstat is not set when error occurs" (#96365) by Kiran Chandramohan · 2 days ago main master
  2. 521b76e [flang] Use %flang_fc1 to avoid options being inserted between %flang and -fc1 (NFC) (#96320) by Kelvin Li · 2 days ago
  3. 7734ad1 [flang] Fix execute_command_line cmdstat is not set when error occurs (#93023) by Yi Wu · 2 days ago
  4. 04c1e5f [flang][debug] Cleanup tests. (NFC) (#96189) by Abid Qadeer · 3 days ago
  5. e0767a4 Adding parsing support for omp loop, target loop directives (#93517) by Anchu Rajendran S · 3 days ago


Flang is a ground-up implementation of a Fortran front end written in modern C++. It started off as the f18 project ( with an aim to replace the previous flang project ( and address its various deficiencies. F18 was subsequently accepted into the LLVM project and rechristened as Flang.

Please note that flang is not ready yet for production usage.

Getting Started

Read more about flang in the docs directory. Start with the compiler overview.

To better understand Fortran as a language and the specific grammar accepted by flang, read Fortran For C Programmers and flang's specifications of the Fortran grammar and the OpenMP grammar.

Treatment of language extensions is covered in this document.

To understand the compilers handling of intrinsics, see the discussion of intrinsics.

To understand how a flang program communicates with libraries at runtime, see the discussion of runtime descriptors.

If you're interested in contributing to the compiler, read the style guide and also review how flang uses modern C++ features.

If you are interested in writing new documentation, follow LLVM's Markdown style guide.

Consult the Getting Started with Flang for information on building and running flang.