diff --git a/src/corelib/tools/qsimd.cpp b/src/corelib/tools/qsimd.cpp
index ad02d2c1476..3e4fdfaaf1f 100644
--- a/src/corelib/tools/qsimd.cpp
+++ b/src/corelib/tools/qsimd.cpp
@@ -636,7 +636,7 @@ int ffsll(quint64 i)
 #endif
 }
 #endif
-#elif defined(Q_OS_ANDROID) || defined(Q_OS_QNX)
+#elif defined(Q_OS_ANDROID) || defined(Q_OS_QNX) || defined(Q_OS_OSX)
 # define ffsll __builtin_ffsll
 #endif