diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -262,6 +262,8 @@
 - Added ``__builtin_elementwise_nearbyint`` for floating point
   types. This allows access to ``llvm.nearbyint`` for arbitrary
   floating-point and vector of floating-point types.
+- The default value of `_MSC_VER` was raised from 1920 to 1933.
+  MSVC 19.33 added undocumented attribute ``[[msvc::constexpr]]``.
 
 New Compiler Flags
 ------------------
diff --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst
--- a/clang/docs/UsersManual.rst
+++ b/clang/docs/UsersManual.rst
@@ -3314,8 +3314,8 @@
 
 For compatibility with existing code that compiles with MSVC, clang defines the
 ``_MSC_VER`` and ``_MSC_FULL_VER`` macros. When on Windows, these default to
-either the same value as the currently installed version of cl.exe, or ``1920``
-and ``192000000`` (respectively). The ``-fms-compatibility-version=`` flag
+either the same value as the currently installed version of cl.exe, or ``1933``
+and ``193300000`` (respectively). The ``-fms-compatibility-version=`` flag
 overrides these values.  It accepts a dotted version tuple, such as 19.00.23506.
 Changing the MSVC compatibility version makes clang behave more like that
 version of MSVC. For example, ``-fms-compatibility-version=19`` will enable
diff --git a/clang/lib/Driver/ToolChains/MSVC.cpp b/clang/lib/Driver/ToolChains/MSVC.cpp
--- a/clang/lib/Driver/ToolChains/MSVC.cpp
+++ b/clang/lib/Driver/ToolChains/MSVC.cpp
@@ -787,11 +787,11 @@
   if (MSVT.empty() &&
       Args.hasFlag(options::OPT_fms_extensions, options::OPT_fno_ms_extensions,
                    IsWindowsMSVC)) {
-    // -fms-compatibility-version=19.20 is default, aka 2019, 16.x
+    // -fms-compatibility-version=19.33 is default, aka 2022, 17.3
     // NOTE: when changing this value, also update
     // clang/docs/CommandGuide/clang.rst and clang/docs/UsersManual.rst
     // accordingly.
-    MSVT = VersionTuple(19, 20);
+    MSVT = VersionTuple(19, 33);
   }
   return MSVT;
 }
diff --git a/clang/test/Driver/cl-options.c b/clang/test/Driver/cl-options.c
--- a/clang/test/Driver/cl-options.c
+++ b/clang/test/Driver/cl-options.c
@@ -753,7 +753,7 @@
 
 // Validate that the default triple is used when run an empty tools dir is specified
 // RUN: %clang_cl -vctoolsdir "" -### -- %s 2>&1 | FileCheck %s --check-prefix VCTOOLSDIR
-// VCTOOLSDIR: "-triple" "{{[a-zA-Z0-9_-]*}}-pc-windows-msvc19.20.0"
+// VCTOOLSDIR: "-triple" "{{[a-zA-Z0-9_-]*}}-pc-windows-msvc19.33.0"
 
 // Validate that built-in include paths are based on the supplied path
 // RUN: %clang_cl --target=aarch64-pc-windows-msvc -vctoolsdir "/fake" -winsdkdir "/foo" -winsdkversion 10.0.12345.0 -### -- %s 2>&1 | FileCheck %s --check-prefix FAKEDIR
@@ -793,7 +793,7 @@
 
 // RUN: %clang_cl -vctoolsdir "" /arm64EC /c -### -- %s 2>&1 | FileCheck --check-prefix=ARM64EC %s 
 // ARM64EC-NOT: /arm64EC has been overridden by specified target
-// ARM64EC: "-triple" "arm64ec-pc-windows-msvc19.20.0"
+// ARM64EC: "-triple" "arm64ec-pc-windows-msvc19.33.0"
 
 // RUN: %clang_cl -vctoolsdir "" /arm64EC /c -target x86_64-pc-windows-msvc  -### -- %s 2>&1 | FileCheck --check-prefix=ARM64EC_OVERRIDE %s
 // ARM64EC_OVERRIDE: warning: /arm64EC has been overridden by specified target: x86_64-pc-windows-msvc; option ignored