diff --git a/libcxx/src/atomic.cpp b/libcxx/src/atomic.cpp
--- a/libcxx/src/atomic.cpp
+++ b/libcxx/src/atomic.cpp
@@ -121,6 +121,7 @@
                                                                __cxx_atomic_contention_t const volatile* __platform_state)
 {
     // We will monitor this value.
+    (void)__contention_state;
     return __cxx_atomic_load(__platform_state, memory_order_acquire);
 }
 static void __libcpp_contention_wait(__cxx_atomic_contention_t volatile* __contention_state,
diff --git a/libcxx/src/support/win32/locale_win32.cpp b/libcxx/src/support/win32/locale_win32.cpp
--- a/libcxx/src/support/win32/locale_win32.cpp
+++ b/libcxx/src/support/win32/locale_win32.cpp
@@ -19,6 +19,7 @@
 // FIXME: base currently unused. Needs manual work to construct the new locale
 locale_t newlocale( int mask, const char * locale, locale_t /*base*/ )
 {
+    (void)mask;
     return {_create_locale( LC_ALL, locale ), locale};
 }