diff --git a/bolt/runtime/CMakeLists.txt b/bolt/runtime/CMakeLists.txt
index 6aa8edb8424a3..8472ce00b4137 100644
--- a/bolt/runtime/CMakeLists.txt
+++ b/bolt/runtime/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 include(CheckIncludeFiles)
 include(GNUInstallDirs)
 
diff --git a/clang/CMakeLists.txt b/clang/CMakeLists.txt
index 4aa0545e8d733..8220a9dbfd4db 100644
--- a/clang/CMakeLists.txt
+++ b/clang/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
   set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
@@ -11,13 +11,6 @@ include(${LLVM_COMMON_CMAKE_UTILS}/Modules/CMakePolicy.cmake
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   project(Clang)
   set(CLANG_BUILT_STANDALONE TRUE)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
 endif()
 
 # Must go below project(..)
diff --git a/clang/tools/scan-build-py/tests/functional/exec/CMakeLists.txt b/clang/tools/scan-build-py/tests/functional/exec/CMakeLists.txt
index 007ad4530d6dc..95c6fdb610e0f 100644
--- a/clang/tools/scan-build-py/tests/functional/exec/CMakeLists.txt
+++ b/clang/tools/scan-build-py/tests/functional/exec/CMakeLists.txt
@@ -1,6 +1,6 @@
 project(exec C)
 
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 include(CheckCCompilerFlag)
 check_c_compiler_flag("-std=c99" C99_SUPPORTED)
diff --git a/cmake/Modules/CMakePolicy.cmake b/cmake/Modules/CMakePolicy.cmake
index 0ec32ad8637f3..8a3445c40cb52 100644
--- a/cmake/Modules/CMakePolicy.cmake
+++ b/cmake/Modules/CMakePolicy.cmake
@@ -1,5 +1,10 @@
 # CMake policy settings shared between LLVM projects
 
+# CMP0091: MSVC runtime library flags are selected by an abstraction.
+# New in CMake 3.15. https://cmake.org/cmake/help/latest/policy/CMP0091.html
+if(POLICY CMP0091)
+  cmake_policy(SET CMP0091 OLD)
+endif()
 # CMP0114: ExternalProject step targets fully adopt their steps.
 # New in CMake 3.19: https://cmake.org/cmake/help/latest/policy/CMP0114.html
 if(POLICY CMP0114)
diff --git a/compiler-rt/CMakeLists.txt b/compiler-rt/CMakeLists.txt
index c5a7b2478e504..6489aa17c2292 100644
--- a/compiler-rt/CMakeLists.txt
+++ b/compiler-rt/CMakeLists.txt
@@ -3,24 +3,19 @@
 # An important constraint of the build is that it only produces libraries
 # based on the ability of the host toolchain to target various platforms.
 
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
+
+set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
+include(${LLVM_COMMON_CMAKE_UTILS}/Modules/CMakePolicy.cmake
+  NO_POLICY_SCOPE)
 
 # Check if compiler-rt is built as a standalone project.
 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR OR COMPILER_RT_STANDALONE_BUILD)
   project(CompilerRT C CXX ASM)
   set(COMPILER_RT_STANDALONE_BUILD TRUE)
   set_property(GLOBAL PROPERTY USE_FOLDERS ON)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
 endif()
 
-set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
-
 # Add path for custom compiler-rt modules.
 list(INSERT CMAKE_MODULE_PATH 0
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
diff --git a/compiler-rt/lib/builtins/CMakeLists.txt b/compiler-rt/lib/builtins/CMakeLists.txt
index a302306cc3021..c3e22a8f354fc 100644
--- a/compiler-rt/lib/builtins/CMakeLists.txt
+++ b/compiler-rt/lib/builtins/CMakeLists.txt
@@ -3,14 +3,7 @@
 # architecture-specific code in various subdirectories.
 
 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-  cmake_minimum_required(VERSION 3.13.4)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
+  cmake_minimum_required(VERSION 3.20.0)
 
   set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
   project(CompilerRTBuiltins C ASM)
diff --git a/compiler-rt/lib/crt/CMakeLists.txt b/compiler-rt/lib/crt/CMakeLists.txt
index 771652f438f81..32fd61b1fa11e 100644
--- a/compiler-rt/lib/crt/CMakeLists.txt
+++ b/compiler-rt/lib/crt/CMakeLists.txt
@@ -1,12 +1,5 @@
 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-  cmake_minimum_required(VERSION 3.13.4)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
+  cmake_minimum_required(VERSION 3.20.0)
 
   set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
   project(CompilerRTCRT C)
diff --git a/flang/CMakeLists.txt b/flang/CMakeLists.txt
index e47456a0fb938..4c0b9a84cc5bf 100644
--- a/flang/CMakeLists.txt
+++ b/flang/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
   set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
@@ -39,13 +39,6 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   message("Building Flang as a standalone project.")
   project(Flang)
   set(FLANG_STANDALONE_BUILD ON)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
 else()
   set(FLANG_STANDALONE_BUILD OFF)
 endif()
diff --git a/flang/lib/Decimal/CMakeLists.txt b/flang/lib/Decimal/CMakeLists.txt
index a81d329b4a5de..3116ff68ea262 100644
--- a/flang/lib/Decimal/CMakeLists.txt
+++ b/flang/lib/Decimal/CMakeLists.txt
@@ -1,5 +1,5 @@
 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-  cmake_minimum_required(VERSION 3.13.4)
+  cmake_minimum_required(VERSION 3.20.0)
 
   project(FortranDecimal C CXX)
 
diff --git a/flang/runtime/CMakeLists.txt b/flang/runtime/CMakeLists.txt
index 47166692e2795..85845c02b3054 100644
--- a/flang/runtime/CMakeLists.txt
+++ b/flang/runtime/CMakeLists.txt
@@ -7,14 +7,7 @@
 #===------------------------------------------------------------------------===#
 
 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-  cmake_minimum_required(VERSION 3.13.4)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
+  cmake_minimum_required(VERSION 3.20.0)
 
   project(FlangRuntime C CXX)
 
diff --git a/libc/CMakeLists.txt b/libc/CMakeLists.txt
index 80e9ead40db64..317ac08441b8d 100644
--- a/libc/CMakeLists.txt
+++ b/libc/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 # Include LLVM's cmake policies.
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
diff --git a/libc/examples/hello_world/CMakeLists.txt b/libc/examples/hello_world/CMakeLists.txt
index 89bf35c0340d0..1561cdc1c3bf5 100644
--- a/libc/examples/hello_world/CMakeLists.txt
+++ b/libc/examples/hello_world/CMakeLists.txt
@@ -1,5 +1,5 @@
 project(hello_world)
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 include(../examples.cmake)
 
 add_example(
diff --git a/libclc/CMakeLists.txt b/libclc/CMakeLists.txt
index 4a1c8b1ba4932..9daef8265c16f 100644
--- a/libclc/CMakeLists.txt
+++ b/libclc/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 project( libclc VERSION 0.2.0 LANGUAGES CXX C)
 
diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
index d3ed4a82b82d6..c44d05f6599cd 100644
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -4,7 +4,7 @@
 #===============================================================================
 # Setup Project
 #===============================================================================
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
 
diff --git a/libcxxabi/CMakeLists.txt b/libcxxabi/CMakeLists.txt
index ae89796f6fcf8..218558e3a8f42 100644
--- a/libcxxabi/CMakeLists.txt
+++ b/libcxxabi/CMakeLists.txt
@@ -4,7 +4,7 @@
 # Setup Project
 #===============================================================================
 
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
 
diff --git a/libunwind/CMakeLists.txt b/libunwind/CMakeLists.txt
index 6f12a160307d1..bd49dfbe53b37 100644
--- a/libunwind/CMakeLists.txt
+++ b/libunwind/CMakeLists.txt
@@ -2,7 +2,7 @@
 # Setup Project
 #===============================================================================
 
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
 
diff --git a/libunwind/src/CMakeLists.txt b/libunwind/src/CMakeLists.txt
index 2eabbe06d1d1d..ef34174438727 100644
--- a/libunwind/src/CMakeLists.txt
+++ b/libunwind/src/CMakeLists.txt
@@ -30,8 +30,7 @@ set(LIBUNWIND_ASM_SOURCES
 # CMake doesn't work correctly with assembly on AIX. Workaround by compiling
 # as C files as well.
 if((APPLE AND CMAKE_VERSION VERSION_LESS 3.19) OR
-   (MINGW AND CMAKE_VERSION VERSION_LESS 3.17) OR
-   (${CMAKE_SYSTEM_NAME} MATCHES "AIX"))
+   (MINGW AND CMAKE_VERSION VERSION_LESS 3.17))
   set_source_files_properties(${LIBUNWIND_ASM_SOURCES} PROPERTIES LANGUAGE C)
 endif()
 
diff --git a/lld/CMakeLists.txt b/lld/CMakeLists.txt
index 1e9e47393196d..a24330d2f18e9 100644
--- a/lld/CMakeLists.txt
+++ b/lld/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
   set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
@@ -11,13 +11,6 @@ include(${LLVM_COMMON_CMAKE_UTILS}/Modules/CMakePolicy.cmake
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   project(lld)
   set(LLD_BUILT_STANDALONE TRUE)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
 endif()
 
 # Must go below project(..)
diff --git a/lldb/CMakeLists.txt b/lldb/CMakeLists.txt
index 39f8e8e62a4e3..4a53d7ef3d0da 100644
--- a/lldb/CMakeLists.txt
+++ b/lldb/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
   set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
@@ -19,13 +19,6 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   project(lldb)
   set(LLDB_BUILT_STANDALONE TRUE)
   set(LLVM_INCLUDE_TESTS ON CACHE INTERNAL "")
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
 endif()
 
 # Must go below project(..)
diff --git a/lldb/tools/debugserver/CMakeLists.txt b/lldb/tools/debugserver/CMakeLists.txt
index 4940ea488682a..74afea804598b 100644
--- a/lldb/tools/debugserver/CMakeLists.txt
+++ b/lldb/tools/debugserver/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 project(Debugserver LANGUAGES C CXX ASM-ATT)
 
@@ -7,13 +7,6 @@ include(GNUInstallDirs)
 
 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   set(LLDB_BUILT_STANDALONE TRUE)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
 
   set(CMAKE_MODULE_PATH
     ${CMAKE_MODULE_PATH}
diff --git a/llvm-libgcc/CMakeLists.txt b/llvm-libgcc/CMakeLists.txt
index 91c40bbf1cf3f..de42d908c3711 100644
--- a/llvm-libgcc/CMakeLists.txt
+++ b/llvm-libgcc/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 if (NOT IS_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}/../libunwind")
   message(FATAL_ERROR "llvm-libgcc requires being built in a monorepo layout with libunwind available")
diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
index c381d7cf0f802..dfe81ad0e2ee3 100644
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -1,13 +1,6 @@
 # See docs/CMake.html for instructions about how to build LLVM with CMake.
 
-cmake_minimum_required(VERSION 3.13.4)
-if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-    "minimum version of CMake required to build LLVM will become 3.20.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.20.0 now to avoid issues in the future!")
-endif()
+cmake_minimum_required(VERSION 3.20.0)
 
 set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
 include(${LLVM_COMMON_CMAKE_UTILS}/Modules/CMakePolicy.cmake
diff --git a/llvm/docs/CMake.rst b/llvm/docs/CMake.rst
index 6eb90c46c52e2..a403b3500764f 100644
--- a/llvm/docs/CMake.rst
+++ b/llvm/docs/CMake.rst
@@ -34,7 +34,7 @@ Quick start
 We use here the command-line, non-interactive CMake interface.
 
 #. `Download <http://www.cmake.org/cmake/resources/software.html>`_ and install
-   CMake. Version 3.13.4 is the minimum required.
+   CMake. Version 3.20.0 is the minimum required.
 
 #. Open a shell. Your development tools must be reachable from this shell
    through the PATH environment variable.
@@ -911,7 +911,7 @@ and uses them to build a simple application ``simple-tool``.
 
 .. code-block:: cmake
 
-  cmake_minimum_required(VERSION 3.13.4)
+  cmake_minimum_required(VERSION 3.20.0)
   project(SimpleProject)
 
   find_package(LLVM REQUIRED CONFIG)
diff --git a/llvm/docs/GettingStarted.rst b/llvm/docs/GettingStarted.rst
index 2324d5a9eba5d..a3e0903122e09 100644
--- a/llvm/docs/GettingStarted.rst
+++ b/llvm/docs/GettingStarted.rst
@@ -280,7 +280,7 @@ uses the package and provides other details.
 =========================================================== ============ ==========================================
 Package                                                     Version      Notes
 =========================================================== ============ ==========================================
-`CMake <http://cmake.org/>`__                               >=3.13.4     Makefile/workspace generator
+`CMake <http://cmake.org/>`__                               >=3.20.0     Makefile/workspace generator
 `GCC <http://gcc.gnu.org/>`_                                >=7.1.0      C/C++ compiler\ :sup:`1`
 `python <http://www.python.org/>`_                          >=3.6        Automated test suite\ :sup:`2`
 `zlib <http://zlib.net>`_                                   >=1.2.3.4    Compression library\ :sup:`3`
diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
index 5cd13f04e87ce..a3c9d93ac65c0 100644
--- a/llvm/docs/ReleaseNotes.rst
+++ b/llvm/docs/ReleaseNotes.rst
@@ -47,6 +47,11 @@ Non-comprehensive list of changes in this release
 Update on required toolchains to build LLVM
 -------------------------------------------
 
+With LLVM 17.x we raised the version requirement of CMake used to build LLVM.
+The new requirements are as follows:
+
+* CMake >= 3.20.0
+
 Changes to the LLVM IR
 ----------------------
 
diff --git a/mlir/CMakeLists.txt b/mlir/CMakeLists.txt
index cd38836e21ec9..f31403aebb226 100644
--- a/mlir/CMakeLists.txt
+++ b/mlir/CMakeLists.txt
@@ -1,5 +1,5 @@
 # MLIR project.
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
   set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
@@ -11,13 +11,6 @@ include(${LLVM_COMMON_CMAKE_UTILS}/Modules/CMakePolicy.cmake
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   project(mlir)
   set(MLIR_STANDALONE_BUILD TRUE)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
 endif()
 
 # Must go below project(..)
diff --git a/mlir/examples/standalone/CMakeLists.txt b/mlir/examples/standalone/CMakeLists.txt
index 65461c048b3f2..038242ba1437a 100644
--- a/mlir/examples/standalone/CMakeLists.txt
+++ b/mlir/examples/standalone/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 project(standalone-dialect LANGUAGES CXX C)
 
 set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR ON)
diff --git a/openmp/CMakeLists.txt b/openmp/CMakeLists.txt
index e7403e5f60f6a..04678cbd4f33d 100644
--- a/openmp/CMakeLists.txt
+++ b/openmp/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
 
@@ -11,14 +11,7 @@ list(INSERT CMAKE_MODULE_PATH 0
 # llvm/runtimes/ will set OPENMP_STANDALONE_BUILD.
 if (OPENMP_STANDALONE_BUILD OR "${CMAKE_SOURCE_DIR}" STREQUAL "${CMAKE_CURRENT_SOURCE_DIR}")
   set(OPENMP_STANDALONE_BUILD TRUE)
-  project(openmp C CXX)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
+  project(openmp C CXX ASM)
 endif()
 
 # Must go below project(..)
diff --git a/openmp/cmake/DetectTestCompiler/CMakeLists.txt b/openmp/cmake/DetectTestCompiler/CMakeLists.txt
index bc2aa52fbc1cf..8ea7ab8d45ba1 100644
--- a/openmp/cmake/DetectTestCompiler/CMakeLists.txt
+++ b/openmp/cmake/DetectTestCompiler/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 project(DetectTestCompiler C CXX)
 
 include(CheckCCompilerFlag)
diff --git a/openmp/docs/SupportAndFAQ.rst b/openmp/docs/SupportAndFAQ.rst
index 249eb18b82a26..c50433bb5b6ed 100644
--- a/openmp/docs/SupportAndFAQ.rst
+++ b/openmp/docs/SupportAndFAQ.rst
@@ -307,7 +307,7 @@ require a few additions.
 
 .. code-block:: cmake
 
-  cmake_minimum_required(VERSION 3.13.4)
+  cmake_minimum_required(VERSION 3.20.0)
   project(offloadTest VERSION 1.0 LANGUAGES CXX)
 
   list(APPEND CMAKE_MODULE_PATH "${PATH_TO_OPENMP_INSTALL}/lib/cmake/openmp")
@@ -318,7 +318,7 @@ require a few additions.
   target_link_libraries(offload PRIVATE OpenMPTarget::OpenMPTarget_NVPTX)
   target_sources(offload PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/src/Main.cpp)
 
-Using this module requires at least CMake version 3.13.4. Supported languages
+Using this module requires at least CMake version 3.20.0. Supported languages
 are C and C++ with Fortran support planned in the future. Compiler support is
 best for Clang but this module should work for other compiler vendors such as
 IBM, GNU.
diff --git a/openmp/libompd/src/CMakeLists.txt b/openmp/libompd/src/CMakeLists.txt
index f361fcf35a273..0402a01772010 100644
--- a/openmp/libompd/src/CMakeLists.txt
+++ b/openmp/libompd/src/CMakeLists.txt
@@ -9,7 +9,7 @@
 #
 
 project (libompd)
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 add_library (ompd SHARED TargetValue.cpp omp-debug.cpp omp-state.cpp omp-icv.cpp)
 
diff --git a/openmp/libomptarget/plugins/remote/src/CMakeLists.txt b/openmp/libomptarget/plugins/remote/src/CMakeLists.txt
index 6299fb38ee8b4..8a16963c913a1 100644
--- a/openmp/libomptarget/plugins/remote/src/CMakeLists.txt
+++ b/openmp/libomptarget/plugins/remote/src/CMakeLists.txt
@@ -10,7 +10,7 @@
 #
 ##===----------------------------------------------------------------------===##
 
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 # Define the suffix for the runtime messaging dumps.
 add_definitions(-DTARGET_NAME=RPC)
diff --git a/openmp/runtime/src/CMakeLists.txt b/openmp/runtime/src/CMakeLists.txt
index 0e778ec14536f..bb58222645147 100644
--- a/openmp/runtime/src/CMakeLists.txt
+++ b/openmp/runtime/src/CMakeLists.txt
@@ -133,8 +133,6 @@ libomp_get_asmflags(LIBOMP_CONFIGURED_ASMFLAGS)
 # Set the compiler flags for each type of source
 set_source_files_properties(${LIBOMP_CXXFILES} PROPERTIES COMPILE_FLAGS "${LIBOMP_CONFIGURED_CXXFLAGS}")
 set_source_files_properties(${LIBOMP_ASMFILES} ${LIBOMP_GNUASMFILES} PROPERTIES COMPILE_FLAGS "${LIBOMP_CONFIGURED_ASMFLAGS}")
-# Let the compiler handle the GNU assembly files
-set_source_files_properties(${LIBOMP_GNUASMFILES} PROPERTIES LANGUAGE C)
 
 # Remove any cmake-automatic linking of the standard C++ library.
 # We neither need (nor want) the standard C++ library dependency even though we compile c++ files.
diff --git a/openmp/tools/Modules/FindOpenMPTarget.cmake b/openmp/tools/Modules/FindOpenMPTarget.cmake
index 3591a49f685b1..424294090d5d0 100644
--- a/openmp/tools/Modules/FindOpenMPTarget.cmake
+++ b/openmp/tools/Modules/FindOpenMPTarget.cmake
@@ -79,7 +79,7 @@ be used to override the standard flag searching for a given compiler.
 # TODO: Test more compilers
 
 cmake_policy(PUSH)
-cmake_policy(VERSION 3.13.4)
+cmake_policy(VERSION 3.20.0)
 
 find_package(OpenMP ${OpenMPTarget_FIND_VERSION} REQUIRED)
 
diff --git a/openmp/tools/Modules/README.rst b/openmp/tools/Modules/README.rst
index f19619e389b37..b8cc5f08b390b 100644
--- a/openmp/tools/Modules/README.rst
+++ b/openmp/tools/Modules/README.rst
@@ -26,7 +26,7 @@ require a few additions.
 
 .. code-block:: cmake
 
-  cmake_minimum_required(VERSION 3.13.4)
+  cmake_minimum_required(VERSION 3.20.0)
   project(offloadTest VERSION 1.0 LANGUAGES CXX)
 
   list(APPEND CMAKE_MODULE_PATH "${PATH_TO_OPENMP_INSTALL}/lib/cmake/openmp")
@@ -37,7 +37,7 @@ require a few additions.
   target_link_libraries(offload PRIVATE OpenMPTarget::OpenMPTarget_NVPTX)
   target_sources(offload PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/src/Main.cpp)
 
-Using this module requires at least CMake version 3.13.4. Supported languages
+Using this module requires at least CMake version 3.20.0. Supported languages
 are C and C++ with Fortran support planned in the future. If your application
 requires building for a specific device architecture you can set the
 ``OpenMPTarget_<device>_ARCH=<flag>`` variable. Compiler support is best for
diff --git a/polly/CMakeLists.txt b/polly/CMakeLists.txt
index 536f11f968292..5d0f2cd7f00ec 100644
--- a/polly/CMakeLists.txt
+++ b/polly/CMakeLists.txt
@@ -1,14 +1,7 @@
 # Check if this is a in tree build.
 if (NOT DEFINED LLVM_MAIN_SRC_DIR)
   project(Polly)
-  cmake_minimum_required(VERSION 3.13.4)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
+  cmake_minimum_required(VERSION 3.20.0)
   set(POLLY_STANDALONE_BUILD TRUE)
 endif()
 
diff --git a/pstl/CMakeLists.txt b/pstl/CMakeLists.txt
index 2461522349ee0..255e22af9a26b 100644
--- a/pstl/CMakeLists.txt
+++ b/pstl/CMakeLists.txt
@@ -5,7 +5,7 @@
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 #
 #===----------------------------------------------------------------------===##
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 
 set(PARALLELSTL_VERSION_FILE "${CMAKE_CURRENT_SOURCE_DIR}/include/pstl/internal/pstl_config.h")
 file(STRINGS "${PARALLELSTL_VERSION_FILE}" PARALLELSTL_VERSION_SOURCE REGEX "#define _PSTL_VERSION .*$")
diff --git a/runtimes/CMakeLists.txt b/runtimes/CMakeLists.txt
index 37cab6e17ee05..599529852688f 100644
--- a/runtimes/CMakeLists.txt
+++ b/runtimes/CMakeLists.txt
@@ -1,16 +1,13 @@
 # This file handles building LLVM runtime sub-projects.
-cmake_minimum_required(VERSION 3.13.4)
-if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-    "minimum version of CMake required to build LLVM will become 3.20.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.20.0 now to avoid issues in the future!")
-endif()
-project(Runtimes C CXX ASM)
+cmake_minimum_required(VERSION 3.20.0)
 
 # Add path for custom and the LLVM build's modules to the CMake module path.
 set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
+include(${LLVM_COMMON_CMAKE_UTILS}/Modules/CMakePolicy.cmake
+  NO_POLICY_SCOPE)
+
+project(Runtimes C CXX ASM)
+
 list(INSERT CMAKE_MODULE_PATH 0
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules"