check_cxx_source_runs("
      #include <smmintrin.h>
      int main ()
      {
        volatile __m128 a, b;
        float vals[4] = {1, 2, 3, 4};
        const int mask = 123;
        a = _mm_loadu_ps (vals);
        b = a;
        b = _mm_dp_ps (a, a, 4);
        _mm_storeu_ps (vals,b);
        return (0);
      }"
            HAVE_SSE4_1_EXTENSIONS)

elseif(HAVE_SSE4_1_EXTENSIONS)