Here's an AVX-2 implementation that assumes it can read up to 31 bytes past the end of the input: https://godbolt.org/z/r33h75j5h https://godbolt.org/z/r33h75j5

Here's an AVX-2 implementation that assumes it can read up to 31 bytes past the end of the input: https://godbolt.org/z/r33h75j5h https://godbolt.org/z/r33h75j5h (yes, that's autogenerated C) Requires -fno-unroll-loops as otherwise clang gets overly unroll-y; the code is fast enough. Tail is dealt with by blending the originally read value with the new one.