Index: clang/CMakeLists.txt
===================================================================
--- clang/CMakeLists.txt
+++ clang/CMakeLists.txt
@@ -1,4 +1,6 @@
 cmake_minimum_required(VERSION 3.13.4)
+include(${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules/CMakePolicy.cmake
+  NO_POLICY_SCOPE)
 
 # If we are not building as a part of LLVM, build Clang as an
 # standalone project, using LLVM as an external library:
Index: cmake/Modules/CMakePolicy.cmake
===================================================================
--- /dev/null
+++ cmake/Modules/CMakePolicy.cmake
@@ -0,0 +1,12 @@
+# CMake policy settings shared between LLVM projects
+
+# 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)
+  cmake_policy(SET CMP0114 OLD)
+endif()
+# CMP0116: Ninja generators transform `DEPFILE`s from `add_custom_command()`
+# New in CMake 3.20. https://cmake.org/cmake/help/latest/policy/CMP0116.html
+if(POLICY CMP0116)
+  cmake_policy(SET CMP0116 OLD)
+endif()
Index: flang/CMakeLists.txt
===================================================================
--- flang/CMakeLists.txt
+++ flang/CMakeLists.txt
@@ -1,4 +1,6 @@
 cmake_minimum_required(VERSION 3.13.4)
+include(${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules/CMakePolicy.cmake
+  NO_POLICY_SCOPE)
 
 set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR ON)
 
Index: lld/CMakeLists.txt
===================================================================
--- lld/CMakeLists.txt
+++ lld/CMakeLists.txt
@@ -1,4 +1,6 @@
 cmake_minimum_required(VERSION 3.13.4)
+include(${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules/CMakePolicy.cmake
+  NO_POLICY_SCOPE)
 
 # If we are not building as a part of LLVM, build LLD as an
 # standalone project, using LLVM as an external library:
Index: lldb/CMakeLists.txt
===================================================================
--- lldb/CMakeLists.txt
+++ lldb/CMakeLists.txt
@@ -1,4 +1,6 @@
 cmake_minimum_required(VERSION 3.13.4)
+include(${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules/CMakePolicy.cmake
+  NO_POLICY_SCOPE)
 
 # Add path for custom modules.
 set(CMAKE_MODULE_PATH
Index: lldb/cmake/modules/LLDBStandalone.cmake
===================================================================
--- lldb/cmake/modules/LLDBStandalone.cmake
+++ lldb/cmake/modules/LLDBStandalone.cmake
@@ -1,9 +1,3 @@
-# CMP0116: Ninja generators transform `DEPFILE`s from `add_custom_command()`
-# New in CMake 3.20. https://cmake.org/cmake/help/latest/policy/CMP0116.html
-if(POLICY CMP0116)
-  cmake_policy(SET CMP0116 OLD)
-endif()
-
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
   set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
 endif()
Index: llvm/CMakeLists.txt
===================================================================
--- llvm/CMakeLists.txt
+++ llvm/CMakeLists.txt
@@ -1,17 +1,8 @@
 # See docs/CMake.html for instructions about how to build LLVM with CMake.
 
 cmake_minimum_required(VERSION 3.13.4)
-
-# 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)
-  cmake_policy(SET CMP0114 OLD)
-endif()
-# CMP0116: Ninja generators transform `DEPFILE`s from `add_custom_command()`
-# New in CMake 3.20. https://cmake.org/cmake/help/latest/policy/CMP0116.html
-if(POLICY CMP0116)
-  cmake_policy(SET CMP0116 OLD)
-endif()
+include(${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules/CMakePolicy.cmake
+  NO_POLICY_SCOPE)
 
 set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR ON)
 
Index: mlir/CMakeLists.txt
===================================================================
--- mlir/CMakeLists.txt
+++ mlir/CMakeLists.txt
@@ -1,4 +1,7 @@
 # MLIR project.
+cmake_minimum_required(VERSION 3.13.4)
+include(${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules/CMakePolicy.cmake
+  NO_POLICY_SCOPE)
 
 # Check if MLIR is built as a standalone project.
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
@@ -10,8 +13,6 @@
 include(GNUInstallDirs)
 
 if(MLIR_STANDALONE_BUILD)
-  cmake_minimum_required(VERSION 3.13.4)
-
   find_package(LLVM CONFIG REQUIRED)
   set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${LLVM_CMAKE_DIR})
   include(HandleLLVMOptions)