Five free C C++ Fortran compiler families

Five modern, currently-supported compiler families are free-to-use for C, C++ and Fortran.

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.

GNUgcc: C17g++ C++20gfortran: F2018
Intel oneAPIicx: C17icpx: C++20ifx: F2018
LLVMclang: C17clang++: C++20flang-fl8: F2018
NVidia HPC SDKnvc: C11nvc++: C++20nvfortran: F2003
IBM OpenXLxlc: C11xlc++: C++14xlf: F2008

Intel oneAPI compilers are free to use for any user. The Intel performance libraries like MKL, IPP, and TBB are available at no cost.

LLVM Clang and Flang have significant industry support, including from Nvidia, and are known for high performance.

Nvidia HPC SDK is free to use. A key feature of the HPC SDK compilers is intrinsic support for CUDA Fortran.

IBM OpenXL LLVM-based compilers are currently for POWER CPUs only e.g. ppc64le. IBM OpenXL compilers do not work with a typical x86-based computer.