diff --git a/core/lib/Drupal/Core/Cache/ApcuBackend.php b/core/lib/Drupal/Core/Cache/ApcuBackend.php
index b8a31be..a77941a 100644
--- a/core/lib/Drupal/Core/Cache/ApcuBackend.php
+++ b/core/lib/Drupal/Core/Cache/ApcuBackend.php
@@ -274,9 +274,9 @@ public function invalidate($cid) {
    * {@inheritdoc}
    */
   public function invalidateMultiple(array $cids) {
-    foreach ($this->getMultiple($cids) as $cache) {
+    foreach (apc_fetch(array_map(array($this, 'getApcuKey'), $cids)) as $key => $cache) {
       $cache->expire = REQUEST_TIME - 1;
-      apc_store($this->getApcuKey($cache->cid), $cache, 1);
+      apc_store($key, $cache, 1);
     }
   }
 
@@ -295,11 +295,12 @@ public function invalidateAll() {
    */
   public function deleteTags(array $tags) {
     foreach ($this->flattenTags($tags) as $tag) {
-      apc_inc($this->deletionsTagsPrefix . $tag, 1, $success);
+      $tag_key = $this->deletionsTagsPrefix . $tag;
+      apc_inc($tag_key, 1, $success);
       if (!$success) {
-        apc_store($this->deletionsTagsPrefix . $tag, 1);
+        apc_store($tag_key, 1);
       }
-      unset(static::$tagCache['deletions'][$tag]);
+      unset(static::$tagCache['deletions'][$tag_key]);
     }
   }
 
@@ -308,11 +309,12 @@ public function deleteTags(array $tags) {
    */
   public function invalidateTags(array $tags) {
     foreach ($this->flattenTags($tags) as $tag) {
-      apc_inc($this->invalidationsTagsPrefix . $tag, 1, $success);
+      $tag_key = $this->invalidationsTagsPrefix . $tag;
+      apc_inc($tag_key, 1, $success);
       if (!$success) {
-        apc_store($this->invalidationsTagsPrefix . $tag, 1);
+        apc_store($tag_key, 1);
       }
-      unset(static::$tagCache['invalidations'][$tag]);
+      unset(static::$tagCache['invalidations'][$tag_key]);
     }
   }
 
@@ -359,24 +361,21 @@ protected function checksumTags(array $tags) {
 
     foreach ($this->flattenTags($tags) as $tag) {
       foreach (array('deletions', 'invalidations') as $type) {
-        if (isset(static::$tagCache[$type][$tag])) {
-          $checksum[$type] += static::$tagCache[$type][$tag];
+        $tag_key = $this->{$type . 'TagsPrefix'} . $tag;
+        if (isset(static::$tagCache[$type][$tag_key])) {
+          $checksum[$type] += static::$tagCache[$type][$tag_key];
         }
         else {
-          $query_tags[$type][] = $this->{$type . 'TagsPrefix'} . $tag;
+          $query_tags[$type][] = $tag_key;
         }
       }
     }
 
     foreach (array('deletions', 'invalidations') as $type) {
       if ($query_tags[$type]) {
-        $prefix_length = strlen($this->{$type . 'TagsPrefix'});
         $result = apc_fetch($query_tags[$type]);
-        foreach ($result as $key => $value) {
-          $tag = substr($key, $prefix_length);
-          static::$tagCache[$type][$tag] = $value;
-          $checksum[$type] += $value;
-        }
+        static::$tagCache[$type] = array_merge(static::$tagCache[$type], $result);
+        $checksum[$type] += array_sum($result);
       }
     }
 
diff --git a/core/modules/system/src/Tests/Cache/GenericCacheBackendUnitTestBase.php b/core/modules/system/src/Tests/Cache/GenericCacheBackendUnitTestBase.php
index 6b591fa..050cf03 100644
--- a/core/modules/system/src/Tests/Cache/GenericCacheBackendUnitTestBase.php
+++ b/core/modules/system/src/Tests/Cache/GenericCacheBackendUnitTestBase.php
@@ -560,6 +560,12 @@ function testInvalidate() {
     // Calling invalidateMultiple() with an empty array should not cause an
     // error.
     $this->assertFalse($backend->invalidateMultiple(array()));
+
+    // Test that an invalidated item is deleted with deleteTags().
+    $backend->set('test5', 5, Cache::PERMANENT, array('test_tag' => 5));
+    $backend->invalidate('test5');
+    $backend->deleteTags(array('test_tag' => 5));
+    $this->assertFalse($backend->get('test5', TRUE));
   }
 
   /**
@@ -643,6 +649,18 @@ public function testInvalidateAll() {
     $this->assertTrue($backend->get('test2', TRUE), 'Second key has not been deleted.');
     // Test that calling invalidateAll() does not change data.
     $this->assertIdentical($backend->get('test1', TRUE)->data, 1);
+
+    // Test that an invalidated item is deleted with deleteTags().
+    $backend->set('test4', 4, Cache::PERMANENT, array('test_tag' => 4));
+    $backend->invalidateAll();
+    $backend->deleteTags(array('test_tag' => 4));
+    $this->assertFalse($backend->get('test4', TRUE));
+
+    // Test that a deleted item is still deleted after invalidateAll().
+    $backend->set('test5', 5, Cache::PERMANENT, array('test_tag' => 5));
+    $backend->deleteTags(array('test_tag' => 5));
+    $backend->invalidateAll();
+    $this->assertFalse($backend->get('test5', TRUE));
   }
 
 }