This is a port of the AVX2 and SSE2 bytecount functions from the Rust bytecount crate to C, including runtime CPU feature detection.
It isn't yet set up as a library, just a trivial benchmark against the naive implementation.
$ aclocal
$ autoconf
$ automake --add-missing
$ ./configure
$ make
$ ./bench
Supported configure flags:
--disable-runtime-dispatch, enables only the scalar fallback bytecounts--disable-runtime-avx2, disable AVX2 version--disable-runtime-sse2, disable SSE2 version