It's been some months since hearing anything on the commercially-focused Zapcc compiler while this morning I received an email announcing the v1.0 release. The announcement read in part, "Zapcc is a Clang based C++ compiler with unique in-memory caching technology, enabling drastic reduction of build times, without any additional machines or network use. For example, WebKit compiles x5.5 faster with Zapcc, Qt is x4.6 and even LLVM is x2.08 faster. Incremental builds are accelerated even further, often x10-x50 faster, up to real time immediate compilations. Following a successful beta phase, Zapcc 1.0 is now generally available, offering high levels of stability and correctness."
Zapcc can be downloaded from Zapcc.com but first you must fill out a basic information form to get access. Some of their benchmark numbers can be found via this page. The company does use the Phoronix Test Suite for carrying out many of their compiler performance tests.