GCC vs. Clang Compiler Benchmarks On POWER9 With Raptor's Blackbird
Even with libomp OpenMP support present for Clang, GCC was faster with its OpenMP threaded performance in GraphicsMagick.
GCC had a 9% lead over Clang on POWER9 for the Himeno pressure solver.
Where Clang can compete with GCC even on IBM POWER is with speedy build times.
Clang was also competitive with GCC in the AV1 video decoder dav1d.
In a number of the other tests, Clang was at least within the realm of the performance of GCC and several times quite competitive.