62 Benchmarks, 12 Systems, 4 Compilers: Our Most Extensive Benchmarks Yet Of GCC vs. Clang Performance

With the PolyBench-C polyhedral benchmark, what was interesting to note is that for the most part the Clang and GCC performance across this diverse range of systems was almost identical... But the interesting bit is the Intel Xeon Silver 4108 and Core i9 7980XE CPUs both performing noticeably better with GCC over Clang. Potentially explaining this is those two CPUs have AVX-512 and perhaps better utilized currently on the GCC side.

Of interest with the FFTW benchmark was seeing GCC 8.2 doing much better on the 2700X / 2990WX / EPYC 7601 Zen systems but the performance dropping back with GCC 9.0. On the Intel side, both AVX-512 Core i9 / Xeon Scalable systems saw nice performance improvements over Clang with GCC 8.2 and now moreso with the upcoming GCC 9.1.

The HMMer molecular biology benchmark was interesting in that with a number of systems the Clang performance was better than GCC, but for the older AMD systems and select Intel systems, GCC was still faster. So this case was a mixed bag between the compilers.

MAFFT is bringing better performance on the range of systems tested with GCC 9 compared to the current GCC 8 release, but that largely makes its performance in line with Clang.