I'm using G++ 4.6.2 and visual C++ 2010.
Currently using G++ 4.6.2 only addition and subtraction of polynomials is using the packed double instructions.
Any hint on how to achieve the same for multiplication and divison.

And then there is the operation of "apply":

Having a polynomial z(y) and one y(x):

z = ay + by*y + cy*y^2 + dy*y^3 + ...

y = ax + bx*x + cx*x^2 + dx*x^3 + ...

The task is to get z(x).

Currently I'm using a class containing a double array containing the coefficients.