CompCert
CompCert is a formally verified optimizing compiler for a large subset of the C99 programming language which currently targets PowerPC, ARM, RISC-V, x86 and x86-64 architectures. This project, led by Xavier Leroy, started officially in 2005, funded by the French institutes ANR and INRIA. The compiler is specified, programmed and proven in Coq. It aims to be used for programming embedded systems requiring reliability. The performance of its generated code is often close to that of GCC at optimization level -O1, and always better than that of GCC without optimizations.
Since 2015 AbsInt offers commercial licenses, provides support and maintenance, and contributes to the advancement of the tool. CompCert is released under a noncommercial license, and is therefore not free software, although some of its source files are dual-licensed with the GNU General Public License version 2 or later or are available under the terms of other licenses.