Licensed under the GPLv3 or later, version 4.8 of the GCC not only brings with it performance improvements but also adds memory error detector AddressSanitizer; and race condition detection tool the ThreadSanitizer. Developers wanting to build their own version of GCC should have at their disposal a C++ compiler that understands C++ 2003.
The release announcement notes that users who are looking to enable Graphite framework for loop optimizations will need CLooG version 0.18.0 and ISL version 0.11.1.
GCC 4.8.0 source code can be downloaded from mirrors as well as project's SVN server. For in-depth information on compiler the GCC manuals can be referred to and for a list of changes one may refer to the change log.