Five free C C++ Fortran compiler families

13 April, 2019

Dozens of “free” compilers exist for C, C++ and Fortran. However, only five compiler families available at no charge support the modern features of these popular compiled languages. This list covers four compiler families available at no charge that support most of:

C17
C++17
Fortran 2008

GCC

GCC has broad support of modern standards on a very wide range of computing platforms. GCC’s downside in some cases can be slower runtime performance than compilers having less broad language and platform support.

LLVM

LLVM Clang and Flang have significant industry support, including from Nvidia, and are known for high performance, but somewhat less language feature support and less broad platform support than GCC.

clang C17 support. Since Clang 6, defaults to C11.
clang++ C++17 support
flang Fortran 2008 support includes submodule. Flang has really great performance compared to GCC.

PGI

PGI Community Edition is free to use, and has performance comparable to Intel compilers in many cases. PGI ≥ 19 should be used for modern Fortran. PGI supports CUDA Fortran.

pgcc C17 support
pgc++ C++17 support
pgfortran Fortran 2008 support includes submodule and error stop

Intel

Intel compilers are a paid product in general. For non-commercial purposes, including:

educators
students
open-source projects

the Intel compilers are available at no charge. The Intel performance libraries like MKL, IPP, TBB and more are available at no cost with more liberal use terms.

IBM XL

IBM XL compilers are currently for POWER CPUs only e.g. ppc64le. IBM XL compilers do not work with a typical x86-based computer. If you have a $2000 Raptor IBM POWER9 desktop, then IBM XL may be for you.

The IBM XL compilers are high-performance compilers that have a free community edition. IBM XL Fortran has wide support for Fortran 2008.