Index: include/__config
===================================================================
--- include/__config
+++ include/__config
@@ -881,7 +881,7 @@
 #  if defined(__GNUC__) && ((__GNUC__ >= 5) || (__GNUC__ == 4 && \
    (__GNUC_MINOR__ >= 3 || __GNUC_PATCHLEVEL__ >= 2))) && !defined(__GXX_RTTI)
 #    define _LIBCPP_NO_RTTI
-#  elif (defined(_MSC_VER) && !defined(__clang__)) && !defined(_CPPRTTI)
+#  elif defined(_LIBCPP_MSVC) && !defined(_CPPRTTI)
 #    define _LIBCPP_NO_RTTI
 #  endif
 #endif
Index: include/__undef___deallocate
===================================================================
--- include/__undef___deallocate
+++ include/__undef___deallocate
@@ -10,7 +10,7 @@
 
 #ifdef __deallocate
 #if !defined(_LIBCPP_DISABLE_MACRO_CONFLICT_WARNINGS)
-#if defined(_MSC_VER) && !defined(__clang__)
+#if defined(_LIBCPP_MSVC)
 _LIBCPP_WARNING("macro __deallocate is incompatible with C++.  #undefining __deallocate")
 #else
 #warning: macro __deallocate is incompatible with C++.  #undefining __deallocate
Index: include/__undef_min_max
===================================================================
--- include/__undef_min_max
+++ include/__undef_min_max
@@ -10,7 +10,7 @@
 
 #ifdef min
 #if !defined(_LIBCPP_DISABLE_MACRO_CONFLICT_WARNINGS)
-#if defined(_MSC_VER) && ! defined(__clang__)
+#if defined(_LIBCPP_MSVC)
 _LIBCPP_WARNING("macro min is incompatible with C++.  Try #define NOMINMAX "
                 "before any Windows header. #undefing min")
 #else
@@ -22,7 +22,7 @@
 
 #ifdef max
 #if !defined(_LIBCPP_DISABLE_MACRO_CONFLICT_WARNINGS)
-#if defined(_MSC_VER) && ! defined(__clang__)
+#if defined(_LIBCPP_MSVC)
 _LIBCPP_WARNING("macro max is incompatible with C++.  Try #define NOMINMAX "
                 "before any Windows header. #undefing max")
 #else
Index: include/ext/hash_map
===================================================================
--- include/ext/hash_map
+++ include/ext/hash_map
@@ -207,7 +207,7 @@
 #include <ext/__hash>
 
 #if __DEPRECATED
-#if defined(_MSC_VER) && ! defined(__clang__)
+#if defined(_LIBCPP_MSVC)
     _LIBCPP_WARNING("Use of the header <ext/hash_map> is deprecated.  Migrate to <unordered_map>")
 #else
 #   warning Use of the header <ext/hash_map> is deprecated.  Migrate to <unordered_map>
Index: include/ext/hash_set
===================================================================
--- include/ext/hash_set
+++ include/ext/hash_set
@@ -199,7 +199,7 @@
 #include <ext/__hash>
 
 #if __DEPRECATED
-#if defined(_MSC_VER) && ! defined(__clang__)
+#if defined(_LIBCPP_MSVC)
     _LIBCPP_WARNING("Use of the header <ext/hash_set> is deprecated.  Migrate to <unordered_set>")
 #else
 #   warning Use of the header <ext/hash_set> is deprecated.  Migrate to <unordered_set>
Index: src/exception.cpp
===================================================================
--- src/exception.cpp
+++ src/exception.cpp
@@ -116,7 +116,7 @@
     return __cxa_uncaught_exception() ? 1 : 0;
 # endif
 #else  // __APPLE__
-#   if defined(_MSC_VER) && ! defined(__clang__)
+#   if defined(_LIBCPP_MSVC)
         _LIBCPP_WARNING("uncaught_exceptions not yet implemented")
 #   else
 #       warning uncaught_exception not yet implemented
@@ -189,7 +189,7 @@
 #elif defined(__GLIBCXX__)
     reinterpret_cast<__exception_ptr::exception_ptr*>(this)->~exception_ptr();
 #else
-#   if defined(_MSC_VER) && ! defined(__clang__)
+#   if defined(_LIBCPP_MSVC)
         _LIBCPP_WARNING("exception_ptr not yet implemented")
 #   else
 #       warning exception_ptr not yet implemented
@@ -208,7 +208,7 @@
     new (reinterpret_cast<void*>(this)) __exception_ptr::exception_ptr(
         reinterpret_cast<const __exception_ptr::exception_ptr&>(other));
 #else
-#   if defined(_MSC_VER) && ! defined(__clang__)
+#   if defined(_LIBCPP_MSVC)
         _LIBCPP_WARNING("exception_ptr not yet implemented")
 #   else
 #       warning exception_ptr not yet implemented
@@ -233,7 +233,7 @@
         reinterpret_cast<const __exception_ptr::exception_ptr&>(other);
     return *this;
 #else
-#   if defined(_MSC_VER) && ! defined(__clang__)
+#   if defined(_LIBCPP_MSVC)
         _LIBCPP_WARNING("exception_ptr not yet implemented")
 #   else
 #       warning exception_ptr not yet implemented
@@ -277,7 +277,7 @@
     ptr.__ptr_ = __cxa_current_primary_exception();
     return ptr;
 #else
-#   if defined(_MSC_VER) && ! defined(__clang__)
+#   if defined(_LIBCPP_MSVC)
         _LIBCPP_WARNING( "exception_ptr not yet implemented" )
 #   else
 #       warning exception_ptr not yet implemented
@@ -299,7 +299,7 @@
 #elif defined(__GLIBCXX__)
     rethrow_exception(reinterpret_cast<__exception_ptr::exception_ptr&>(p));
 #else
-#   if defined(_MSC_VER) && ! defined(__clang__)
+#   if defined(_LIBCPP_MSVC)
         _LIBCPP_WARNING("exception_ptr not yet implemented")
 #   else
 #       warning exception_ptr not yet implemented
Index: src/include/atomic_support.h
===================================================================
--- src/include/atomic_support.h
+++ src/include/atomic_support.h
@@ -29,7 +29,7 @@
 #endif
 
 #if !defined(_LIBCPP_HAS_ATOMIC_BUILTINS) && !defined(_LIBCPP_HAS_NO_THREADS)
-# if defined(_MSC_VER) && !defined(__clang__)
+# if defined(_LIBCPP_MSVC)
     _LIBCPP_WARNING("Building libc++ without __atomic builtins is unsupported")
 # else
 #   warning Building libc++ without __atomic builtins is unsupported
Index: src/thread.cpp
===================================================================
--- src/thread.cpp
+++ src/thread.cpp
@@ -99,7 +99,7 @@
 #else  // defined(CTL_HW) && defined(HW_NCPU)
     // TODO: grovel through /proc or check cpuid on x86 and similar
     // instructions on other architectures.
-#   if defined(_MSC_VER) && ! defined(__clang__)
+#   if defined(_LIBCPP_MSVC)
         _LIBCPP_WARNING("hardware_concurrency not yet implemented")
 #   else
 #       warning hardware_concurrency not yet implemented
Index: utils/google-benchmark/include/benchmark/macros.h
===================================================================
--- utils/google-benchmark/include/benchmark/macros.h
+++ utils/google-benchmark/include/benchmark/macros.h
@@ -33,7 +33,7 @@
 #define BENCHMARK_ALWAYS_INLINE __attribute__((always_inline))
 #define BENCHMARK_NOEXCEPT noexcept
 #define BENCHMARK_NOEXCEPT_OP(x) noexcept(x)
-#elif defined(_MSC_VER) && !defined(__clang__)
+#elif defined(_LIBCPP_MSVC)
 #define BENCHMARK_UNUSED
 #define BENCHMARK_ALWAYS_INLINE __forceinline
 #if _MSC_VER >= 1900