title: Unknown type name __m256 - Intel intrinsics for AVX not recognized?
body: <p>I'm trying to test some of the Intel Intrinsics to see how they work. So, i created a function to do that for me and this is the code:</p>
  
  <pre><code>void test_intel_256()
  {
  __m256 res,vec1,vec2;
  
  __M256_MM_SET_PS(vec1, 7.0, 7.0, 7.0, 7.0, 7.0, 7.0, 7.0, 7.0);
  __M256_MM_SET_PS(vec1, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0);
  
  __M256_MM_ADD_PS(res,vec1,vec2);
  
  if (res[0] ==9 &amp;&amp; res[1] ==9 &amp;&amp; res[2] ==9 &amp;&amp; res[3] ==9 
    &amp;&amp; res[4] ==9 &amp;&amp; res[5] ==9 &amp;&amp; res[6] ==9 &amp;&amp; res[7] ==9 )
      printf("Addition : OK!\n");
  else
      printf("Addition : FAILED!\n");
  }
  </code></pre>
  
  <p>But then i'm getting these errors:</p>
  
  <pre><code>error: unknown type name ‘__m256’
  error: subscripted value is neither array nor pointer nor vector
  error: subscripted value is neither array nor pointer nor vector 
  error: subscripted value is neither array nor pointer nor vector
  error: subscripted value is neither array nor pointer nor vector
  error: subscripted value is neither array nor pointer nor vector
  error: subscripted value is neither array nor pointer nor vector
  error: subscripted value is neither array nor pointer nor vector
  error: subscripted value is neither array nor pointer nor vector
  error: subscripted value is neither array nor pointer nor vector
  </code></pre>
  
  <p>Meaning that the compiler is not recognizing the __m256 type and by consequence he can't see the res as an array of floats.
  I'm including these libraries <strong>mmintrin.h</strong>, <strong>emmintrin.h</strong>, <strong>xmmintrin.h</strong>
  and i'm using eclipse Mars</p>
  
  <p>So what i want to know is whether the problem is from the compiler or the hardware or something else?
  and how can i solve it?
  Thank you!</p>