title: warning: 'assume_aligned' attribute directive ignored
body: <p>I just started with C++ and i think the best way is to look at source codes. I have code as follows in the header file.</p>
  
  <pre><code>#ifdef _MSC_VER
  #define MYAPP_CACHE_ALIGNED_RETURN /* not supported */
  #else
  #define MYAPP_CACHE_ALIGNED_RETURN __attribute__((assume_aligned(64)))
  #endif
  </code></pre>
  
  <p>I am using <code>gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-11)</code> and its quite old. I get this warning during compilation:</p>
  
  <pre><code> warning: 'assume_aligned' attribute directiv e ignored [-Wattributes] –
  </code></pre>
  
  <p>How can I make the if statement more specific to fix the the warning during compilation?</p>