[teo_zero]

> The lut is zeroed except for the indices corresponding to the vowels, which contain it self

So in the comparison vs. the original str, vowels get a true and consonants get a false. Doesn't the "==" then returns true if all the chars are vowels?

[camel-cdr]

I used the C operators as short cuts to denote SIMD operations. So the == would be element wise and return a mask of the vowels in the input vector.