CompCert is a  formally verified optimizing compiler for a large subset of the C programming language which currently targets PowerPC, ARM and 32-bit x86 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 proved 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  (version 3) at optimization level -O1, and always better than that of GCC without optimizations.