GCC 10 vs. Clang 10 Compiler Performance On AMD Zen 2 + Intel Cascade Lake

The libgav1 AV1 encoder saw faster performance on Clang over GCC for both Intel and AMD. This isn't entirely surprising considering Google generally uses Clang as their default compiler these days in software development. Once libgav1 has more hand-tuned x86_64 Assembly, the compiler difference may also be narrowed.

The Dav1d AV1 decoder in some cases saw slightly better performance when moving from GCC 9 to GCC 10 while the Clang performance was basically the same.

One area with the dav1d performance where Clang did hit a big slowdown compared to GCC was when decoding AV1 10-bit content.

Clang meanwhile did see some advantages in some scenarios with Intel's SVT-AV1 encoder.