diff --git a/core/lib/Drupal/Core/Path/AliasManager.php b/core/lib/Drupal/Core/Path/AliasManager.php
index 9ebaa8c..82c19bd 100644
--- a/core/lib/Drupal/Core/Path/AliasManager.php
+++ b/core/lib/Drupal/Core/Path/AliasManager.php
@@ -132,7 +132,7 @@ public function getAliasByPath($path, $language = NULL) {
     // Check the path whitelist, if the top-level part before the first /
     // is not in the list, then there is no need to do anything further,
     // it is not in the database.
-    if (!$this->whitelist->get(strtok($path, '/'))) {
+    if (empty($path) || !$this->whitelist->get(strtok($path, '/'))) {
       return $path;
     }
 
@@ -150,7 +150,7 @@ public function getAliasByPath($path, $language = NULL) {
     }
 
     // If we already know that there are no aliases for this path simply return.
-    if (empty($path) || !empty($this->noAlias[$language][$path])) {
+    if (!empty($this->noAlias[$language][$path])) {
       return $path;
     }
 
diff --git a/core/modules/path/lib/Drupal/path/Form/PathFormBase.php b/core/modules/path/lib/Drupal/path/Form/PathFormBase.php
index 251fbe3..ca507d1 100644
--- a/core/modules/path/lib/Drupal/path/Form/PathFormBase.php
+++ b/core/modules/path/lib/Drupal/path/Form/PathFormBase.php
@@ -137,7 +137,7 @@ public function buildForm(array $form, array &$form_state, $pid = NULL) {
    */
   public function validateForm(array &$form, array &$form_state) {
     $source = &$form_state['values']['source'];
-    $source = $this->aliasManager->getSystemPath($source);
+    $source = $this->aliasManager->getPathByAlias($source);
     $alias = $form_state['values']['alias'];
     // Language is only set if language.module is enabled, otherwise save for all
     // languages.
@@ -160,7 +160,7 @@ public function submitForm(array &$form, array &$form_state) {
 
     $pid = isset($form_state['values']['pid']) ? $form_state['values']['pid'] : 0;
     $source = &$form_state['values']['source'];
-    $source = $this->aliasManager->getSystemPath($source);
+    $source = $this->aliasManager->getPathByAlias($source);
     $alias = $form_state['values']['alias'];
     // Language is only set if language.module is enabled, otherwise save for all
     // languages.