How to generate a sse4.2 popcnt machine instruction

Using the c program:

int main(int argc , char** argv)
{

  return  __builtin_popcountll(0xf0f0f0f0f0f0f0f0);

}

and the compiler line (gcc 4.4 - Intel Xeon L3426):

gcc -msse4.2 poptest.c -o poptest

I do NOT get the builtin popcnt insruction rather the compiler generates a lookup table and computes the popcount that way. The resulting binary is over 8000 bytes. (Yuk!)

Thanks so much for any assistance.