GCC vs. Clang Compiler Benchmarks On POWER9 With Raptor's Blackbird

In the SciMark 2.0 C micro-benchmarks is one of the cases where LLVM Clang overall was outperforming GCC. In SciMark2, GCC 9.1.0 ended up being slightly faster than the current GCC 10 development state.

Clang's lead in SciMark mostly comes down to the FFT, Monte Carlo, and Jacobi sub-tests.

With x264 video encoding, GCC 9.1.0 yielded slightly better performance than LLVM Clang 8.0 while GCC 10.0 was regressing.

Clang failed to build x265 on POWER9, but here again is a case of GCC 9.1 outperforming GCC 10.0.