https://mirrors.edge.kernel.org/pub/tools/llvm/ provides a PGO-optimized LLVM toolchain. It is likely much faster than Distro provided Clang.
You might also want to replace the malloc with mimalloc/snmalloc, which might yield ~10% performance boost.
You might also want to replace the malloc with mimalloc/snmalloc, which might yield ~10% performance boost.