title: Definitive if check
body: <p>Consider this kind of if-statment in a function:</p>
  
  <pre><code>int Foo( void )
  {
      if ( HostCPUInfo::IsSSE3Supported() )
          // SSE3 intrinsic
      else
          // C code
  }
  </code></pre>
  
  <p>I check during the runtime if SSE3 instructions are supported by the host CPU to permit the use of faster intrinsic. But, as I doubt the the return of  HostCPUInfo::IsSSE3Supported() is going to change during the life of my program, is there a way to only make this kind of checks once (maybe during the initialization) ?</p>