From the "fast compilers make me happy" department
PathScale announced today that the EKOPath 4 Compiler Suite is now available as an open source project and free download for Linux, FreeBSD and Solaris. This release includes documentation and the complete development stack, including compiler, debugger, assembler, runtimes and standard libraries. EKOPath is the product of years of ongoing development, representing one of the industries highest performance Intel 64 and AMD C, C++ and Fortran compilers. There do not seem to be any sources available just yet.
(Updated) For those that were wondering, EKOPath is a fully independent version and product. It shares a very distant past with the SGI Pro64 compiler and has evolved into a professional high performance compiler suite.