[ashdnazg]

You could copy the instruction to a 16 byte sized buffer and hash the one/two int64s. Looking at the code sample in the article, there wasn't a single instruction longer than 5 characters, and I suspect that in general instructions with short names are more common than those with long names.

This last fact might actually support the current model, as it grows linearly-ish in the size of the instruction, instead of being constant like hash.