Revert "Revert "Revert "[CMake] Bumps minimum version to 3.20.0."""
This reverts commit 1ef4c3c859728008cf707cad8d67f45ae5070ae1.
Two buildbots still haven't been updated.
GitOrigin-RevId: 44d38022ab29a3156349602733b3459df5beef93
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5d0f2cd..536f11f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,7 +1,14 @@
# Check if this is a in tree build.
if (NOT DEFINED LLVM_MAIN_SRC_DIR)
project(Polly)
- cmake_minimum_required(VERSION 3.20.0)
+ 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()
set(POLLY_STANDALONE_BUILD TRUE)
endif()
