> you can use the same base trick behind a carry lookahead adder

YESSSS.

I've been pointing this out for years and years.

By the point that you're looking at the same propagation delay as a common 64 bit adder you're decoding 64 chunks of 16 bits per cycle. That's 128 bytes, or a 32-64 instructions wide decoder.

That is so much wider than anyone is making or contemplating — or that even makes sense given the size of basic blocks — that it's just a non-issue.