diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp
index 4262899e02..eef375fe72 100644
--- a/src/corelib/tools/qstring.cpp
+++ b/src/corelib/tools/qstring.cpp
@@ -3260,6 +3260,23 @@ static int lastIndexOfHelper(const ushort *haystack, int from, const ushort *nee
     return -1;
 }
 
+static inline int lastIndexOfHelper(
+        const QStringRef &haystack, int from, const QStringRef &needle, Qt::CaseSensitivity cs)
+{
+    return lastIndexOfHelper(reinterpret_cast<const ushort*>(haystack.unicode()), from,
+                             reinterpret_cast<const ushort*>(needle.unicode()), needle.size(), cs);
+}
+
+static inline int lastIndexOfHelper(
+        const QStringRef &haystack, int from, QLatin1String needle, Qt::CaseSensitivity cs)
+{
+    const int size = needle.size();
+    QVarLengthArray<ushort> s(size);
+    qt_from_latin1(s.data(), needle.latin1(), size);
+    return lastIndexOfHelper(reinterpret_cast<const ushort*>(haystack.unicode()), from,
+                             s.data(), size, cs);
+}
+
 /*!
   Returns the index position of the last occurrence of the string \a
   str in this string, searching backward from index position \a
@@ -9816,6 +9833,27 @@ int QStringRef::lastIndexOf(QChar ch, int from, Qt::CaseSensitivity cs) const
     return qt_last_index_of(unicode(), size(), ch, from, cs);
 }
 
+template<typename T>
+static int last_index_of_impl(const QStringRef &haystack, int from, const T &needle, Qt::CaseSensitivity cs)
+{
+    const int sl = needle.size();
+    if (sl == 1)
+        return haystack.lastIndexOf(needle.at(0), from, cs);
+
+    const int l = haystack.size();
+    if (from < 0)
+        from += l;
+    int delta = l - sl;
+    if (from == l && sl == 0)
+        return from;
+    if (uint(from) >= uint(l) || delta < 0)
+        return -1;
+    if (from > delta)
+        from = delta;
+
+    return lastIndexOfHelper(haystack, from, needle, cs);
+}
+
 /*!
   \since 4.8
   \overload lastIndexOf()
@@ -9833,25 +9871,7 @@ int QStringRef::lastIndexOf(QChar ch, int from, Qt::CaseSensitivity cs) const
 */
 int QStringRef::lastIndexOf(QLatin1String str, int from, Qt::CaseSensitivity cs) const
 {
-    const int sl = str.size();
-    if (sl == 1)
-        return lastIndexOf(str.at(0), from, cs);
-
-    const int l = size();
-    if (from < 0)
-        from += l;
-    int delta = l - sl;
-    if (from == l && sl == 0)
-        return from;
-    if (uint(from) >= uint(l) || delta < 0)
-        return -1;
-    if (from > delta)
-        from = delta;
-
-    QVarLengthArray<ushort> s(sl);
-    qt_from_latin1(s.data(), str.latin1(), sl);
-
-    return lastIndexOfHelper(reinterpret_cast<const ushort*>(unicode()), from, s.data(), sl, cs);
+    return last_index_of_impl(*this, from, str, cs);
 }
 
 /*!
@@ -9871,24 +9891,7 @@ int QStringRef::lastIndexOf(QLatin1String str, int from, Qt::CaseSensitivity cs)
 */
 int QStringRef::lastIndexOf(const QStringRef &str, int from, Qt::CaseSensitivity cs) const
 {
-    const int sl = str.size();
-    if (sl == 1)
-        return lastIndexOf(str.at(0), from, cs);
-
-    const int l = size();
-    if (from < 0)
-        from += l;
-    int delta = l - sl;
-    if (from == l && sl == 0)
-        return from;
-    if (uint(from) >= uint(l) || delta < 0)
-        return -1;
-    if (from > delta)
-        from = delta;
-
-    return lastIndexOfHelper(reinterpret_cast<const ushort*>(unicode()), from,
-                             reinterpret_cast<const ushort*>(str.unicode()),
-                             str.size(), cs);
+    return last_index_of_impl(*this, from, str, cs);
 }
 
 /*!