diff --git a/libcxx/include/atomic b/libcxx/include/atomic
--- a/libcxx/include/atomic
+++ b/libcxx/include/atomic
@@ -2699,6 +2699,13 @@
 #define ATOMIC_FLAG_INIT {false}
 #define ATOMIC_VAR_INIT(__v) {__v}
 
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS)
+# if defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER >= 1400
+#  pragma clang deprecated(ATOMIC_FLAG_INIT)
+#  pragma clang deprecated(ATOMIC_VAR_INIT)
+# endif
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS)
+
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP_ATOMIC
diff --git a/libcxx/src/barrier.cpp b/libcxx/src/barrier.cpp
--- a/libcxx/src/barrier.cpp
+++ b/libcxx/src/barrier.cpp
@@ -22,7 +22,7 @@
     struct alignas(64) /* naturally-align the heap state */ __state_t
     {
         struct {
-            __atomic_base<__barrier_phase_t> __phase = ATOMIC_VAR_INIT(0);
+          __atomic_base<__barrier_phase_t> __phase{0};
         } __tickets[64];
     };
 
diff --git a/libcxx/src/experimental/memory_resource.cpp b/libcxx/src/experimental/memory_resource.cpp
--- a/libcxx/src/experimental/memory_resource.cpp
+++ b/libcxx/src/experimental/memory_resource.cpp
@@ -97,8 +97,7 @@
 __default_memory_resource(bool set = false, memory_resource * new_res = nullptr) noexcept
 {
 #ifndef _LIBCPP_HAS_NO_ATOMIC_HEADER
-    _LIBCPP_SAFE_STATIC static atomic<memory_resource*> __res =
-        ATOMIC_VAR_INIT(&res_init.resources.new_delete_res);
+    _LIBCPP_SAFE_STATIC static atomic<memory_resource*> __res{&res_init.resources.new_delete_res};
     if (set) {
         new_res = new_res ? new_res : new_delete_resource();
         // TODO: Can a weaker ordering be used?
diff --git a/libcxx/src/ios.cpp b/libcxx/src/ios.cpp
--- a/libcxx/src/ios.cpp
+++ b/libcxx/src/ios.cpp
@@ -137,7 +137,7 @@
 
 // xalloc
 #if defined(_LIBCPP_HAS_C_ATOMIC_IMP) && !defined(_LIBCPP_HAS_NO_THREADS)
-atomic<int> ios_base::__xindex_ = ATOMIC_VAR_INIT(0);
+atomic<int> ios_base::__xindex_{0};
 #else
 int ios_base::__xindex_ = 0;
 #endif
diff --git a/libcxx/test/libcxx/atomics/atomics.flag/init_bool.pass.cpp b/libcxx/test/libcxx/atomics/atomics.flag/init_bool.pass.cpp
--- a/libcxx/test/libcxx/atomics/atomics.flag/init_bool.pass.cpp
+++ b/libcxx/test/libcxx/atomics/atomics.flag/init_bool.pass.cpp
@@ -22,7 +22,7 @@
 extern std::atomic_flag global;
 struct X { X() { global.test_and_set(); }};
 X x;
-std::atomic_flag global = ATOMIC_FLAG_INIT;
+std::atomic_flag global{false};
 #endif
 
 int main(int, char**)
diff --git a/libcxx/test/std/atomics/atomics.flag/init.pass.cpp b/libcxx/test/std/atomics/atomics.flag/init.pass.cpp
--- a/libcxx/test/std/atomics/atomics.flag/init.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.flag/init.pass.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 // XFAIL: c++03
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
 
 // <atomic>
 
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_var_init.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_var_init.pass.cpp
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_var_init.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/atomic_var_init.pass.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 // XFAIL: c++03
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
 
 // <atomic>
 
diff --git a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/ctor.pass.cpp b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/ctor.pass.cpp
--- a/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/ctor.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.types.operations/atomics.types.operations.req/ctor.pass.cpp
@@ -41,10 +41,6 @@
       constexpr Atomic a{t};
       assert(a == t);
     }
-    {
-      constexpr Atomic a = ATOMIC_VAR_INIT(t);
-      assert(a == t);
-    }
   }
 };
 
diff --git a/libcxx/test/std/thread/futures/futures.async/async.pass.cpp b/libcxx/test/std/thread/futures/futures.async/async.pass.cpp
--- a/libcxx/test/std/thread/futures/futures.async/async.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.async/async.pass.cpp
@@ -30,7 +30,7 @@
 typedef std::chrono::high_resolution_clock Clock;
 typedef std::chrono::milliseconds ms;
 
-std::atomic_bool invoked = ATOMIC_VAR_INIT(false);
+std::atomic_bool invoked{false};
 
 int f0()
 {