Csmith vs Fuzzowski

Csmith is a free, open-source generator of random C programs for finding compiler bugs through differential testing. Its output avoids undefined behavior and includes statistics for each generated program. A documented workflow compiles programs with GCC and Clang, then compares their outputs to identify differences. The tool can also create material for a C test suite when users do not want to write one themselves. Command-line options shown by csmith -h and csmith -hh customize random generation. Csmith runs locally on Linux and Windows. Ubuntu source builds require g++, CMake, and m4, followed by CMake and make; Windows builds are documented with Visual Studio or WSL. The project says it should build on most modern machines with a C++ compiler. Generated programs may loop indefinitely, so execution timeouts are recommended. The repository includes a COPYING license file. Bug reports and suggestions go through GitHub issues, with discussion on a mailing list; maintainers warn replies may be delayed.

Fuzzowski has no write-up on Specifiction yet; its figures are above.