diff --git a/src/xmlpatterns/functions/qstringvaluefns.cpp b/src/xmlpatterns/functions/qstringvaluefns.cpp
index 766856c43e986dd20f053b1c95f698e73a6ae622..6c4bac515606d242bd93d98f7bd1efa5dfd1493d 100644
--- a/src/xmlpatterns/functions/qstringvaluefns.cpp
+++ b/src/xmlpatterns/functions/qstringvaluefns.cpp
@@ -221,7 +221,7 @@ Expression::Ptr NormalizeUnicodeFN::compress(const StaticContext::Ptr &context)
         m_normForm = static_cast<QString::NormalizationForm>(
                 determineNormalizationForm(context->dynamicContext()));
 
-        if(m_normForm == -1)
+        if (int(m_normForm) == -1)
             return m_operands.first();
 
         /* Remove the operand since we don't need it anymore. */