title: Double question marks ('??') vs if when assigning same var
body: <p>Referring to the following <a href="https://stackoverflow.com/a/446839/799379">SE answer</a>.</p>
  
  <p>When writing</p>
  
  <pre><code>A = A ?? B;
  </code></pre>
  
  <p>it is the same as</p>
  
  <pre><code>if( null != A )
      A = A;
  else
      A = B;
  </code></pre>
  
  <p>Does that mean that</p>
  
  <pre><code>if( null == A ) A = B;
  </code></pre>
  
  <p>would be preferred, performance wise?</p>
  
  <p>Or can I assume that the compiler optimizes the code when the same object is in the <code>??</code> notation?</p>