Benchmarking LLVM's Clang OpenMP Support Against GCC
GraphicsMagick is one of many open-source programs that relies upon OpenMP for offering better performance on multi-core systems. With GraphicsMagick's image blur operation, the OpenMP performance of LLVM Clang 3.4 wasn't quite up to the performance level of GCC 4.9 but is certainly faster than LLVM Clang 3.4 without any OpenMP support.
With the image sharpening task in OpenMP, the Clang OpemMP-supported code almost caught up to GCC 4.9 but still was a fair bit short.
Image resizing for GraphicsMagick broke with the clang-omp code.
The HWB Color Space code saw minimal improvement with the OpenMP version of Clang compared to where GCC 4.9 is running.
The Smallpt path tracing benchmark now runs at the same speed as GCC 4.9 thanks to the OpenMP support for this global illumination renderer.