Intel Xeon Cascade Lake Compiler Performance - GCC 9/10 vs. LLVM Clang 8/9

Something we've seen on other systems in past compiler comparisons is the Intel MKL-DNN math kernel library benchmark performing much better when built on Clang than GCC.

For Intel's SVT video encoder projects meanwhile the AV1 encoder came out about even while GCC 9 was the fastest for the HEVC and VP9 CPU-based encoders, but in HEVC/VP9 those compilers were doing some odd behavior with regards to the compiler flags that may explain some of the difference.

The VP9 vpxenc performance came out slightly ahead on the LLVM Clang compilers.

While the LLVM Clang compiler has increasingly good OpenMP support these days, in OMP workloads like GraphicsMagick the performance still tends to be better with the GNU Compiler Collection.

GCC also led in the Himeno pressure solver tests.