presto-spi/src/main/java/io/prestosql/spi/type/DoubleType.java/DoubleType/hash
class DoubleType:    @Override
    public long hash(Block block, int position)
    {
        // convert to canonical NaN if necessary
        return AbstractLongType.hash(doubleToLongBits(longBitsToDouble(block.getLong(position, 0))));
    }