diff --git a/src/corelib/io/qloggingregistry.cpp b/src/corelib/io/qloggingregistry.cpp
index ece58cfa87e..aa64410dcda 100644
--- a/src/corelib/io/qloggingregistry.cpp
+++ b/src/corelib/io/qloggingregistry.cpp
@@ -256,7 +256,7 @@ static bool qtLoggingDebug()
             debugMsg("QT_LOGGING_DEBUG environment variable is set.");
         return debug;
     }();
-    return debugEnv;
+    return Q_UNLIKELY(debugEnv);
 }
 
 static QList<QLoggingRule> loadRulesFromFile(const QString &filePath)