diff --git a/libcxx/src/chrono.cpp b/libcxx/src/chrono.cpp
--- a/libcxx/src/chrono.cpp
+++ b/libcxx/src/chrono.cpp
@@ -99,7 +99,7 @@
                                                     nanoseconds::period>>;
 
   // The Windows epoch is Jan 1 1601, the Unix epoch Jan 1 1970.
-  static _LIBCPP_CONSTEXPR const seconds nt_to_unix_epoch{11644473600};
+  static constexpr const seconds nt_to_unix_epoch{11644473600};
 
   FILETIME ft;
 #if (_WIN32_WINNT >= _WIN32_WINNT_WIN8 && WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)) || \
diff --git a/libcxx/src/condition_variable.cpp b/libcxx/src/condition_variable.cpp
--- a/libcxx/src/condition_variable.cpp
+++ b/libcxx/src/condition_variable.cpp
@@ -61,7 +61,7 @@
     __libcpp_timespec_t ts;
     seconds s = duration_cast<seconds>(d);
     typedef decltype(ts.tv_sec) ts_sec;
-    _LIBCPP_CONSTEXPR ts_sec ts_sec_max = numeric_limits<ts_sec>::max();
+    constexpr ts_sec ts_sec_max = numeric_limits<ts_sec>::max();
     if (s.count() < ts_sec_max)
     {
         ts.tv_sec = static_cast<ts_sec>(s.count());
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
@@ -74,7 +74,7 @@
     __null_memory_resource_imp       null_res;
   } resources;
   char dummy;
-  _LIBCPP_CONSTEXPR_SINCE_CXX14 ResourceInitHelper() : resources() {}
+  constexpr ResourceInitHelper() : resources() {}
   ~ResourceInitHelper() {}
 };
 
diff --git a/libcxx/src/filesystem/error.h b/libcxx/src/filesystem/error.h
--- a/libcxx/src/filesystem/error.h
+++ b/libcxx/src/filesystem/error.h
@@ -112,7 +112,7 @@
 template <class T>
 T error_value();
 template <>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX14 void error_value<void>() {}
+inline constexpr void error_value<void>() {}
 template <>
 inline bool error_value<bool>() {
   return false;
@@ -128,7 +128,7 @@
   return uintmax_t(-1);
 }
 template <>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX14 file_time_type error_value<file_time_type>() {
+inline constexpr file_time_type error_value<file_time_type>() {
   return file_time_type::min();
 }
 template <>
diff --git a/libcxx/src/filesystem/time_utils.h b/libcxx/src/filesystem/time_utils.h
--- a/libcxx/src/filesystem/time_utils.h
+++ b/libcxx/src/filesystem/time_utils.h
@@ -147,7 +147,7 @@
           .count();
 
 private:
-  static _LIBCPP_CONSTEXPR fs_duration get_min_nsecs() {
+  static constexpr fs_duration get_min_nsecs() {
     return duration_cast<fs_duration>(
         fs_nanoseconds(min_nsec_timespec) -
         duration_cast<fs_nanoseconds>(fs_seconds(1)));
@@ -157,7 +157,7 @@
                     FileTimeT::duration::min(),
                 "value doesn't roundtrip");
 
-  static _LIBCPP_CONSTEXPR_SINCE_CXX14 bool check_range() {
+  static constexpr bool check_range() {
     // This kinda sucks, but it's what happens when we don't have __int128_t.
     if (sizeof(TimeT) == sizeof(rep)) {
       typedef duration<long long, ratio<3600 * 24 * 365> > Years;
@@ -225,7 +225,7 @@
 
 public:
   template <class CType, class ChronoType>
-  static _LIBCPP_CONSTEXPR_SINCE_CXX14 bool checked_set(CType* out,
+  static constexpr bool checked_set(CType* out,
                                                         ChronoType time) {
     using Lim = numeric_limits<CType>;
     if (time > Lim::max() || time < Lim::min())
@@ -234,7 +234,7 @@
     return true;
   }
 
-  static _LIBCPP_CONSTEXPR_SINCE_CXX14 bool is_representable(TimeSpecT tm) {
+  static constexpr bool is_representable(TimeSpecT tm) {
     if (tm.tv_sec >= 0) {
       return tm.tv_sec < max_seconds ||
              (tm.tv_sec == max_seconds && tm.tv_nsec <= max_nsec);
@@ -245,7 +245,7 @@
     }
   }
 
-  static _LIBCPP_CONSTEXPR_SINCE_CXX14 bool is_representable(FileTimeT tm) {
+  static constexpr bool is_representable(FileTimeT tm) {
     auto secs = duration_cast<fs_seconds>(tm.time_since_epoch());
     auto nsecs = duration_cast<fs_nanoseconds>(tm.time_since_epoch() - secs);
     if (nsecs.count() < 0) {
@@ -258,7 +258,7 @@
     return secs.count() >= TLim::min();
   }
 
-  static _LIBCPP_CONSTEXPR_SINCE_CXX14 FileTimeT
+  static constexpr FileTimeT
   convert_from_timespec(TimeSpecT tm) {
     if (tm.tv_sec >= 0 || tm.tv_nsec == 0) {
       return FileTimeT(fs_seconds(tm.tv_sec) +
@@ -272,7 +272,7 @@
   }
 
   template <class SubSecT>
-  static _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
+  static constexpr bool
   set_times_checked(TimeT* sec_out, SubSecT* subsec_out, FileTimeT tp) {
     auto dur = tp.time_since_epoch();
     auto sec_dur = duration_cast<fs_seconds>(dur);
@@ -289,7 +289,7 @@
     return checked_set(sec_out, sec_dur.count()) &&
            checked_set(subsec_out, subsec_dur.count());
   }
-  static _LIBCPP_CONSTEXPR_SINCE_CXX14 bool convert_to_timespec(TimeSpecT& dest,
+  static constexpr bool convert_to_timespec(TimeSpecT& dest,
                                                                 FileTimeT tp) {
     if (!is_representable(tp))
       return false;
diff --git a/libcxx/src/locale.cpp b/libcxx/src/locale.cpp
--- a/libcxx/src/locale.cpp
+++ b/libcxx/src/locale.cpp
@@ -94,7 +94,7 @@
 
 template <typename T, size_t N>
 inline
-_LIBCPP_CONSTEXPR
+constexpr
 size_t
 countof(const T (&)[N])
 {
@@ -103,7 +103,7 @@
 
 template <typename T>
 inline
-_LIBCPP_CONSTEXPR
+constexpr
 size_t
 countof(const T * const begin, const T * const end)
 {
@@ -1097,7 +1097,7 @@
 const ctype<char>::mask*
 ctype<char>::classic_table() noexcept
 {
-    static _LIBCPP_CONSTEXPR const ctype<char>::mask builtin_table[table_size] = {
+    static constexpr const ctype<char>::mask builtin_table[table_size] = {
         cntrl,                          cntrl,
         cntrl,                          cntrl,
         cntrl,                          cntrl,
diff --git a/libcxx/src/memory.cpp b/libcxx/src/memory.cpp
--- a/libcxx/src/memory.cpp
+++ b/libcxx/src/memory.cpp
@@ -149,7 +149,7 @@
     _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER
 };
 
-_LIBCPP_CONSTEXPR __sp_mut::__sp_mut(void* p) noexcept
+constexpr __sp_mut::__sp_mut(void* p) noexcept
    : __lx_(p)
 {
 }
diff --git a/libcxx/src/memory_resource.cpp b/libcxx/src/memory_resource.cpp
--- a/libcxx/src/memory_resource.cpp
+++ b/libcxx/src/memory_resource.cpp
@@ -74,7 +74,7 @@
     __null_memory_resource_imp null_res;
   } resources;
   char dummy;
-  _LIBCPP_CONSTEXPR_SINCE_CXX14 ResourceInitHelper() : resources() {}
+  constexpr ResourceInitHelper() : resources() {}
   ~ResourceInitHelper() {}
 };
 
diff --git a/libcxx/test/libcxx/input.output/filesystems/class.directory_entry/directory_entry.mods/last_write_time.pass.cpp b/libcxx/test/libcxx/input.output/filesystems/class.directory_entry/directory_entry.mods/last_write_time.pass.cpp
--- a/libcxx/test/libcxx/input.output/filesystems/class.directory_entry/directory_entry.mods/last_write_time.pass.cpp
+++ b/libcxx/test/libcxx/input.output/filesystems/class.directory_entry/directory_entry.mods/last_write_time.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// UNSUPPORTED: c++03
+// UNSUPPORTED: c++03, c++11
 // UNSUPPORTED: availability-filesystem-missing
 // UNSUPPORTED: no-filesystem
 // ADDITIONAL_COMPILE_FLAGS: -I %S/../../../../../../src