Update to Drupal 8.2.0. For more information, see https://www.drupal.org/project/drupal/releases/8.2.0

core/lib/Drupal/Component/Utility/OpCodeCache.php

@@ -9,6 +9,16 @@ namespace Drupal\Component\Utility;
  */
 class OpCodeCache {
 
+  /**
+   * Checks if OpCodeCache is enabled.
+   *
+   * @return bool
+   *   TRUE if opcache is enabled, FALSE otherwise.
+   */
+  public static function isEnabled() {
+    return extension_loaded('Zend OPcache') && ini_get('opcache.enable');
+  }
+
   /**
    * Invalidates a PHP file from a possibly active opcode cache.
    *