This brings back from the dead the AVX table parts of Elena's D15604.
The SSE changes seem more closely bound to the strategy change (since the current costs use the weird "convert to simple types, then look up" form), I'll look into that separately.
Depending on how thorough we need to be shouldn't there be AVX512DQ+AVX512VL UINT_TO_FP cases for 128/256 bit vectors?