title: Is using -O3 with emscripten considered safe?
body: <p>Older version of emscripten (i.e. pre fastcomp) when run with the <code>-O3</code> flag spewed the following warning:</p>
  
  <blockquote>
    <p>WARNING  : Applying some potentially unsafe optimizations! (Use -O2 if this fails.)</p>
  </blockquote>
  
  <p>However, newer versions when run with <code>-O3</code> don't warn at all.</p>
  
  <p>Does this mean that using <code>-O3</code> is now safe?</p>