Bryce Adelstein-Lelbach presented at LinuxCon today on "LLVM-compiled Linux for the Real World." He's been one of many developers working to allow the Linux kernel build under the Apple-sponsored Clang C/C++ compiler as an alternative to using the GNU Compiler Collection (GCC).
For background information on this initiative to make the Linux kernel no longer dependent upon the GCC compiler, see There's Interest In Building The Linux Kernel With Clang. Bryce is a researcher at the Center for Computation and Technology, part of the STE||AR group. Qualcomm is one of the hardware vendors interested in using LLVM/Clang with the Linux kernel for the ARM architecture.
It was in October of 2010 that the original milestone was reached of building the Linux kernel with LLVM/Clang. While it's been two years, there's still non-mainline Linux kernel patches required to build the kernel with LLVM's Clang compiler. There's a Git repository setup by the Linux Foundation that hosts this LLVM Linux work where in the x86 world their patched kernel is currently on the Linux 3.3 kernel where as for ARM hardware they're closely following Git. The mainline LLVM/Clang SVN master is working to build the kernel.
Among the reasons developers have been interested in using the Clang compiler on the Linux kernel comes down to possible performance gains, the diagnostics reporting offered by Clang compared to GCC, the very powerful static analysis support offered by Clang, and just freeing the dependence upon GCC. Forcing code through multiple compilers often tends to lead to cleaner and more portable code.
the LLVM Linux Foundation page.
Other relevant information and initiatives include Decoupling GCC From Debian By Using LLVM/Clang and FreeBSD 10 To Use Clang Compiler, Deprecate GCC.