Overloading conflict with vector types __m128, __m256 in GCC

Question

I've started playing around with AVX instructions on the new Intel's Sandy Bridge processor. I'm using GCC 4.5.2, TDM-GCC 64bit build of MinGW64.

I want to overload operator<< for ostream to be able to print out the vector types __m256, __m128 etc to the console. But I'm running into an overloading conflict. The 2nd function in the following code produces an error "conflicts with previous declaration void f(__vector(8) float)":

void f(__m128 v) {
cout << 4;
}

void f(__m256 v) {
    cout << 8;
}

It seems that the compiler cannot distinguish between the two types and consideres them both f(float __vector).

Is there a way around this? I haven't been able to find anything online. Any help is greatly appreciated.