diff --git a/core/lib/Drupal/Core/DrupalKernel.php b/core/lib/Drupal/Core/DrupalKernel.php
index 19cf29b6de..7926623477 100644
--- a/core/lib/Drupal/Core/DrupalKernel.php
+++ b/core/lib/Drupal/Core/DrupalKernel.php
@@ -1064,38 +1064,6 @@ protected function initializeSettings(Request $request) {
         throw new BadRequestHttpException('The provided host name is not valid for this server.');
       }
     }
-
-    // If the class loader is still the same, possibly
-    // upgrade to an optimized class loader.
-    if ($class_loader_class == get_class($this->classLoader)
-        && Settings::get('class_loader_auto_detect', TRUE)) {
-      $prefix = Settings::getApcuPrefix('class_loader', $this->root);
-      $loader = NULL;
-
-      // We autodetect one of the following three optimized classloaders, if
-      // their underlying extension exists.
-      if (function_exists('apcu_fetch')) {
-        $loader = new ApcClassLoader($prefix, $this->classLoader);
-      }
-      elseif (extension_loaded('wincache')) {
-        $loader = new WinCacheClassLoader($prefix, $this->classLoader);
-      }
-      elseif (extension_loaded('xcache')) {
-        $loader = new XcacheClassLoader($prefix, $this->classLoader);
-      }
-      if (!empty($loader)) {
-        $this->classLoader->unregister();
-        $loader->register();
-        $old_loader = $this->classLoader;
-        $this->classLoader = $loader;
-        // The optimized classloader might be persistent and store cache misses.
-        // For example, once a cache miss is stored in APCu clearing it on a
-        // specific web-head will not clear any other web-heads. Therefore
-        // fallback to the composer class loader that only statically caches
-        // misses.
-        $old_loader->register();
-      }
-    }
   }
 
   /**