title: Crash in Release Mode while generating NSString with arguments
body: <p>I have written Log helper class which has couple of Log functions. All is working well in DEBUG mode. But when I run my code is release mode it is crashing. Below is the code snippet:</p>
  
  <pre><code>+ (void)info:(NSString *)format, ...
  {
      va_list args;
      va_start(args, format);
      va_end(args);
  
      NSString *formatedMessage = [[NSString alloc] initWithFormat:[NSString stringWithFormat:@"INFO %@",format] arguments:args];
  }
  </code></pre>
  
  <p>While creating formatedMessage app is getting crash with below excecption:
  <a href="https://i.stack.imgur.com/CLGgZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/CLGgZ.png" alt="Here is the callback of crash"></a></p>
  
  <p>If I set </p>
  
  <blockquote>
    <p>Build Setting->optimization level to NONE</p>
  </blockquote>
  
  <p>in Release mode all works smooth. Any idea to fix with Optimization Level to </p>
  
  <blockquote>
    <p>Fastest-Smallest</p>
  </blockquote>
  
  <p>in Release mode</p>