diff --git a/src/corelib/io/qiodevice.cpp b/src/corelib/io/qiodevice.cpp
index 81c2bc16959..723cc3e3232 100644
--- a/src/corelib/io/qiodevice.cpp
+++ b/src/corelib/io/qiodevice.cpp
@@ -45,6 +45,7 @@ static void debugBinaryString(const char *input, qint64 maxlen)
 
 #define Q_VOID
 
+Q_DECL_COLD_FUNCTION
 static void checkWarnMessage(const QIODevice *device, const char *function, const char *what)
 {
 #ifndef QT_NO_WARNING_OUTPUT