Most often when running GCC vs. LLVM Clang compiler benchmark comparisons it's done on Intel/AMD x86 hardware or occasionally on ARM when benchmarking an interesting ARMv7/ARMv8 system. However, in having remote access last weekend to the prototype of the Talos Secure Workstation powered by a POWER8 design, I was very anxious to run some compiler benchmarks to see how these open-source compilers compete on the alternative architecture.
Compared to most of my x86/ARM benchmarks of GCC vs. Clang, the LLVM-based compiler seemed even more competitive to the GNU Compiler Collection when it came to running on POWER8. GCC 5.3.1 and LLVM Clang 3.6.2 were the tested compiler versions as found on the Debian Testing environment that was setup for this Linux PPC64LE system. The POWER8 system had 64 cores available and was using the Linux 4.3 kernel. Pretty much it was similar to a stock Debian POWER8 testing environment. The CFLAGS/CXXFLAGS were obviously maintained the same as well during the benchmarking process.
Keep in mind GCC 5.3 is the latest stable series on the GNU front while the LLVM Clang 3.7 series is the latest stable, but Clang 3.6 was what's currently available via Debian testing. GCC 6.1 and LLVM Clang 3.8 will also soon be released. These PowerPC Clang vs. GCC compiler benchmarks were carried out in a fully-automated and reproducible manner using the open-source Phoronix Test Suite benchmarking software.