[flang-commits] [clang] [compiler-rt] [flang] [libc] [libclc] [libcxx] [libcxxabi] [libunwind] [lld] [lldb] [llvm] [mlir] [openmp] [polly] [CMake] Bump the minimum required version to 3.31 (PR #223854)

Tue Sep 15 14:50:08 PDT 2026

llvmorg-github-actions[bot] wrote:



@llvm/pr-subscribers-libcxxabi

@llvm/pr-subscribers-bolt

Author: Petr Hosek (petrhosek)

<details>
<summary>Changes</summary>

This is a follow up to e192ec42b426f6ffbc25419238a90f3c59088587 which changes the warning to an error when using CMake older than 3.31.

See
https://discourse.llvm.org/t/rfc-raising-minimum-required-cmake-version-to-3-31/91086.

---
Full diff: https://github.com/llvm/llvm-project/pull/223854.diff


20 Files Affected:

- (modified) bolt/CMakeLists.txt (+1-8) 
- (modified) clang/CMakeLists.txt (+1-9) 
- (modified) compiler-rt/CMakeLists.txt (+1-9) 
- (modified) flang/CMakeLists.txt (+1-9) 
- (modified) libc/CMakeLists.txt (+1-9) 
- (modified) libclc/CMakeLists.txt (+1-8) 
- (modified) libcxx/CMakeLists.txt (+1-9) 
- (modified) libcxxabi/CMakeLists.txt (+1-9) 
- (modified) libsycl/CMakeLists.txt (+1-8) 
- (modified) libunwind/CMakeLists.txt (+1-9) 
- (modified) lld/CMakeLists.txt (+1-9) 
- (modified) lldb/CMakeLists.txt (+1-9) 
- (modified) llvm-libgcc/CMakeLists.txt (+1-9) 
- (modified) llvm/CMakeLists.txt (+1-8) 
- (modified) mlir/CMakeLists.txt (+1-9) 
- (modified) offload/CMakeLists.txt (+1-9) 
- (modified) openmp/CMakeLists.txt (+1-9) 
- (modified) orc-rt/CMakeLists.txt (+1-8) 
- (modified) polly/CMakeLists.txt (+1-9) 
- (modified) runtimes/CMakeLists.txt (+1-8) 


``````````diff

diff --git a/bolt/CMakeLists.txt b/bolt/CMakeLists.txt
index 8deb5cea0401b..87646a9554ed2 100644
--- a/bolt/CMakeLists.txt
+++ b/bolt/CMakeLists.txt
@@ -1,11 +1,4 @@
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
+cmake_minimum_required(VERSION 3.31.0)
 
 set(LLVM_SUBPROJECT_TITLE "BOLT")
 
diff --git a/clang/CMakeLists.txt b/clang/CMakeLists.txt
index 67bc01754fa28..d398d3b25e29e 100644
--- a/clang/CMakeLists.txt
+++ b/clang/CMakeLists.txt
@@ -1,12 +1,4 @@
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
-
+cmake_minimum_required(VERSION 3.31.0)
 set(LLVM_SUBPROJECT_TITLE "Clang")
 
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
diff --git a/compiler-rt/CMakeLists.txt b/compiler-rt/CMakeLists.txt
index 9e45a43b34287..6d9eb176b0269 100644
--- a/compiler-rt/CMakeLists.txt
+++ b/compiler-rt/CMakeLists.txt
@@ -3,15 +3,7 @@
 # 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 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
-
+cmake_minimum_required(VERSION 3.31.0)
 set(LLVM_SUBPROJECT_TITLE "compiler-rt")
 
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
diff --git a/flang/CMakeLists.txt b/flang/CMakeLists.txt
index d606eed5d4a3b..2d4dbab3b5d81 100644
--- a/flang/CMakeLists.txt
+++ b/flang/CMakeLists.txt
@@ -1,12 +1,4 @@
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
-
+cmake_minimum_required(VERSION 3.31.0)
 set(LLVM_SUBPROJECT_TITLE "Flang")
 
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
diff --git a/libc/CMakeLists.txt b/libc/CMakeLists.txt
index 292e4c90a26a8..7557d5229fb5a 100644
--- a/libc/CMakeLists.txt
+++ b/libc/CMakeLists.txt
@@ -1,12 +1,4 @@
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
-
+cmake_minimum_required(VERSION 3.31.0)
 set(LLVM_SUBPROJECT_TITLE "libc")
 
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
diff --git a/libclc/CMakeLists.txt b/libclc/CMakeLists.txt
index 5829bd9b39eac..f6eb1833e6eeb 100644
--- a/libclc/CMakeLists.txt
+++ b/libclc/CMakeLists.txt
@@ -1,11 +1,4 @@
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
+cmake_minimum_required(VERSION 3.31.0)
 
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   project(libclc VERSION 0.2.0 LANGUAGES CXX C)
diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
index 8841f5d07aaf6..103e3ba0631fd 100644
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -1,15 +1,7 @@
 #===============================================================================
 # Setup Project
 #===============================================================================
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
-
+cmake_minimum_required(VERSION 3.31.0)
 set(LLVM_SUBPROJECT_TITLE "libc++")
 
 # Unset the C++ Standard: other projects sometimes override this global property, which
diff --git a/libcxxabi/CMakeLists.txt b/libcxxabi/CMakeLists.txt
index 6ea3cea30bdbc..0fdf0e1e91f0a 100644
--- a/libcxxabi/CMakeLists.txt
+++ b/libcxxabi/CMakeLists.txt
@@ -4,15 +4,7 @@
 # Setup Project
 #===============================================================================
 
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
-
+cmake_minimum_required(VERSION 3.31.0)
 set(LLVM_SUBPROJECT_TITLE "libc++abi")
 
 set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
diff --git a/libsycl/CMakeLists.txt b/libsycl/CMakeLists.txt
index 609103ce226a6..6e2467361df5a 100644
--- a/libsycl/CMakeLists.txt
+++ b/libsycl/CMakeLists.txt
@@ -1,14 +1,7 @@
 #===============================================================================
 # Setup Project
 #===============================================================================
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
+cmake_minimum_required(VERSION 3.31.0)
 
 set(LLVM_SUBPROJECT_TITLE "libsycl")
 
diff --git a/libunwind/CMakeLists.txt b/libunwind/CMakeLists.txt
index 93a3a0b74c876..7427ba2c059a9 100644
--- a/libunwind/CMakeLists.txt
+++ b/libunwind/CMakeLists.txt
@@ -2,15 +2,7 @@
 # Setup Project
 #===============================================================================
 
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
-
+cmake_minimum_required(VERSION 3.31.0)
 set(LLVM_SUBPROJECT_TITLE "libunwind")
 
 set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
diff --git a/lld/CMakeLists.txt b/lld/CMakeLists.txt
index 5181eb272d5be..d3557dc94e493 100644
--- a/lld/CMakeLists.txt
+++ b/lld/CMakeLists.txt
@@ -1,12 +1,4 @@
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
-
+cmake_minimum_required(VERSION 3.31.0)
 set(LLVM_SUBPROJECT_TITLE "LLD")
 
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
diff --git a/lldb/CMakeLists.txt b/lldb/CMakeLists.txt
index 7f45487c1d2d7..05d443d1273eb 100644
--- a/lldb/CMakeLists.txt
+++ b/lldb/CMakeLists.txt
@@ -1,12 +1,4 @@
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
-
+cmake_minimum_required(VERSION 3.31.0)
 set(LLVM_SUBPROJECT_TITLE "LLDB")
 
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
diff --git a/llvm-libgcc/CMakeLists.txt b/llvm-libgcc/CMakeLists.txt
index a297447327936..131c7729cbfc3 100644
--- a/llvm-libgcc/CMakeLists.txt
+++ b/llvm-libgcc/CMakeLists.txt
@@ -2,15 +2,7 @@
 # Setup Project
 #===============================================================================
 
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
-
+cmake_minimum_required(VERSION 3.31.0)
 set(LLVM_SUBPROJECT_TITLE "LLVM libgcc")
 
 set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
index 825dbce14d67c..3d23219ed9a7c 100644
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -1,12 +1,5 @@
 # See docs/CMake.html for instructions about how to build LLVM with CMake.
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
+cmake_minimum_required(VERSION 3.31.0)
 
 include(CMakeDependentOption)
 
diff --git a/mlir/CMakeLists.txt b/mlir/CMakeLists.txt
index 68df5aed001e2..233fc61ed12d7 100644
--- a/mlir/CMakeLists.txt
+++ b/mlir/CMakeLists.txt
@@ -1,13 +1,5 @@
 # MLIR project.
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
-
+cmake_minimum_required(VERSION 3.31.0)
 set(LLVM_SUBPROJECT_TITLE "MLIR")
 
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
diff --git a/offload/CMakeLists.txt b/offload/CMakeLists.txt
index ade372c3232ef..47884772244de 100644
--- a/offload/CMakeLists.txt
+++ b/offload/CMakeLists.txt
@@ -1,15 +1,7 @@
 # See for https://openmp.llvm.org/SupportAndFAQ.html for instructions on how
 # to build offload with CMake.
 
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
-
+cmake_minimum_required(VERSION 3.31.0)
 set(LLVM_SUBPROJECT_TITLE "liboffload")
 
 # The minimum versions required for dependencies.
diff --git a/openmp/CMakeLists.txt b/openmp/CMakeLists.txt
index f9a89859be7af..f02d1d3e0283e 100644
--- a/openmp/CMakeLists.txt
+++ b/openmp/CMakeLists.txt
@@ -1,12 +1,4 @@
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
-
+cmake_minimum_required(VERSION 3.31.0)
 set(LLVM_SUBPROJECT_TITLE "OpenMP")
 
 set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
diff --git a/orc-rt/CMakeLists.txt b/orc-rt/CMakeLists.txt
index 75050fd2802fc..494e5d6eab251 100644
--- a/orc-rt/CMakeLists.txt
+++ b/orc-rt/CMakeLists.txt
@@ -4,14 +4,7 @@
 # Setup Project
 #===============================================================================
 
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
+cmake_minimum_required(VERSION 3.31.0)
 
 set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
 include(${LLVM_COMMON_CMAKE_UTILS}/Modules/CMakePolicy.cmake
diff --git a/polly/CMakeLists.txt b/polly/CMakeLists.txt
index 48459c61f456f..7a8766b79e0f0 100644
--- a/polly/CMakeLists.txt
+++ b/polly/CMakeLists.txt
@@ -1,15 +1,7 @@
 # Check if this is a in tree build.
 if (NOT DEFINED LLVM_MAIN_SRC_DIR)
   project(Polly)
-  cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
-
+  cmake_minimum_required(VERSION 3.31.0)
   set(POLLY_STANDALONE_BUILD TRUE)
 endif()
 set(LLVM_SUBPROJECT_TITLE "Polly")
diff --git a/runtimes/CMakeLists.txt b/runtimes/CMakeLists.txt
index 61cf25af22870..8afd3ce10bdad 100644
--- a/runtimes/CMakeLists.txt
+++ b/runtimes/CMakeLists.txt
@@ -1,12 +1,5 @@
 # This file handles building LLVM runtime sub-projects.
-cmake_minimum_required(VERSION 3.20.0)
-if("${CMAKE_VERSION}" VERSION_LESS "3.31.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 24, the "
-    "minimum version of CMake required to build LLVM will become 3.31.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.31.0 now to avoid issues in the future.")
-endif()
+cmake_minimum_required(VERSION 3.31.0)
 
 # This file can be used in two ways: the bootstrapping build calls it from
 # llvm/runtimes/CMakeLists.txt where we reuse the build tree of the top-level

``````````

</details>


https://github.com/llvm/llvm-project/pull/223854
