Index: libcxx/include/__config
===================================================================
--- libcxx/include/__config
+++ libcxx/include/__config
@@ -302,6 +302,12 @@
 #define _LIBCPP_NO_EXCEPTIONS
 #endif
 
+#if defined _LIBCPP_NO_EXCEPTIONS
+#define _LIBCPP_NORETURN_IF_NO_EXCEPTIONS
+#else
+#define _LIBCPP_NORETURN_IF_NO_EXCEPTIONS __attribute__((__noreturn__))
+#endif
+
 #if !(__has_feature(cxx_rtti))
 #define _LIBCPP_NO_RTTI
 #endif
Index: libcxx/include/__locale
===================================================================
--- libcxx/include/__locale
+++ libcxx/include/__locale
@@ -1184,7 +1184,7 @@
 _LIBCPP_EXTERN_TEMPLATE2(class _LIBCPP_TYPE_VIS codecvt_byname<char16_t, char, mbstate_t>)
 _LIBCPP_EXTERN_TEMPLATE2(class _LIBCPP_TYPE_VIS codecvt_byname<char32_t, char, mbstate_t>)
 
-_LIBCPP_FUNC_VIS void __throw_runtime_error(const char*);
+_LIBCPP_FUNC_VIS void __throw_runtime_error(const char*) _LIBCPP_NORETURN_IF_NO_EXCEPTIONS;
 
 template <size_t _Np>
 struct __narrow_to_utf8
Index: libcxx/include/deque
===================================================================
--- libcxx/include/deque
+++ libcxx/include/deque
@@ -895,8 +895,8 @@
 class __deque_base_common
 {
 protected:
-    void __throw_length_error() const;
-    void __throw_out_of_range() const;
+    void __throw_length_error() const _LIBCPP_NORETURN_IF_NO_EXCEPTIONS;
+    void __throw_out_of_range() const _LIBCPP_NORETURN_IF_NO_EXCEPTIONS;
 };
 
 template <bool __b>
Index: libcxx/include/future
===================================================================
--- libcxx/include/future
+++ libcxx/include/future
@@ -513,7 +513,7 @@
 };
 
 inline _LIBCPP_ALWAYS_INLINE
-void __throw_future_error(future_errc _Ev)
+void __throw_future_error(future_errc _Ev) _LIBCPP_NORETURN_IF_NO_EXCEPTIONS
 {
 #ifndef _LIBCPP_NO_EXCEPTIONS
     throw future_error(make_error_code(_Ev));
Index: libcxx/include/regex
===================================================================
--- libcxx/include/regex
+++ libcxx/include/regex
@@ -958,7 +958,7 @@
 
 template <regex_constants::error_type _Ev>
 _LIBCPP_ALWAYS_INLINE
-void __throw_regex_error()
+void __throw_regex_error() _LIBCPP_NORETURN_IF_NO_EXCEPTIONS
 {
 #ifndef _LIBCPP_NO_EXCEPTIONS
     throw regex_error(_Ev);
Index: libcxx/include/system_error
===================================================================
--- libcxx/include/system_error
+++ libcxx/include/system_error
@@ -635,7 +635,9 @@
     static string __init(const error_code&, string);
 };
 
-_LIBCPP_FUNC_VIS void __throw_system_error(int ev, const char* what_arg);
+_LIBCPP_FUNC_VIS
+void __throw_system_error(int ev,
+                          const char* what_arg) _LIBCPP_NORETURN_IF_NO_EXCEPTIONS;
 
 _LIBCPP_END_NAMESPACE_STD
 
Index: libcxx/include/vector
===================================================================
--- libcxx/include/vector
+++ libcxx/include/vector
@@ -290,8 +290,8 @@
 {
 protected:
     _LIBCPP_ALWAYS_INLINE __vector_base_common() {}
-    void __throw_length_error() const;
-    void __throw_out_of_range() const;
+    void __throw_length_error() const _LIBCPP_NORETURN_IF_NO_EXCEPTIONS;
+    void __throw_out_of_range() const _LIBCPP_NORETURN_IF_NO_EXCEPTIONS;
 };
 
 template <bool __b>