This is helpful for the use cases that want to rearrange bytes in a fixed pattern, but it cannot yet express a stream vbyte decoder (out = pshufb(in, shuffle_pa

This is helpful for the use cases that want to rearrange bytes in a fixed pattern, but it cannot yet express a stream vbyte decoder (out = pshufb(in, shuffle_patterns[len_mask])) or a check for which bytes are in small set of bytes with distinct lower nibbles and the high bit not set (eq(in, pshufb(set, in))) yet. If it's to be portable it needs an extra instruction on one platform or the other because tbl and vpshufb do different things :(