diff --git a/clang/CMakeLists.txt b/clang/CMakeLists.txt
index 284b2af24ddaa..f092766fa19f0 100644
--- a/clang/CMakeLists.txt
+++ b/clang/CMakeLists.txt
@@ -165,6 +165,13 @@ if(CLANG_ENABLE_LIBXML2)
   endif()
 endif()
 
+if(CLANG_ENABLE_CIR)
+  if (NOT "${LLVM_ENABLE_PROJECTS}" MATCHES "MLIR|mlir")
+    message(FATAL_ERROR
+      "Cannot build ClangIR without MLIR in LLVM_ENABLE_PROJECTS")
+  endif()
+endif()
+
 include(CheckIncludeFile)
 check_include_file(sys/resource.h CLANG_HAVE_RLIMITS)
 
diff --git a/clang/include/clang/CIR/CMakeLists.txt b/clang/include/clang/CIR/CMakeLists.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/include/clang/CMakeLists.txt b/clang/include/clang/CMakeLists.txt
index 0dc9ea5ed8ac8..47ac70cd21690 100644
--- a/clang/include/clang/CMakeLists.txt
+++ b/clang/include/clang/CMakeLists.txt
@@ -1,5 +1,8 @@
 add_subdirectory(AST)
 add_subdirectory(Basic)
+if(CLANG_ENABLE_CIR)
+  add_subdirectory(CIR)
+endif()
 add_subdirectory(Driver)
 add_subdirectory(Parse)
 add_subdirectory(Sema)
diff --git a/clang/include/clang/Config/config.h.cmake b/clang/include/clang/Config/config.h.cmake
index 4015ac8040861..27ed69e21562b 100644
--- a/clang/include/clang/Config/config.h.cmake
+++ b/clang/include/clang/Config/config.h.cmake
@@ -83,4 +83,7 @@
 /* Spawn a new process clang.exe for the CC1 tool invocation, when necessary */
 #cmakedefine01 CLANG_SPAWN_CC1
 
+/* Whether CIR is built into Clang */
+#cmakedefine01 CLANG_ENABLE_CIR
+
 #endif
diff --git a/clang/lib/CIR/CMakeLists.txt b/clang/lib/CIR/CMakeLists.txt
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/lib/CMakeLists.txt b/clang/lib/CMakeLists.txt
index 0cac86451f39e..14ba55360fe05 100644
--- a/clang/lib/CMakeLists.txt
+++ b/clang/lib/CMakeLists.txt
@@ -31,3 +31,7 @@ if(CLANG_INCLUDE_TESTS)
 endif()
 add_subdirectory(Interpreter)
 add_subdirectory(Support)
+
+if(CLANG_ENABLE_CIR)
+  add_subdirectory(CIR)
+endif()
diff --git a/clang/test/CMakeLists.txt b/clang/test/CMakeLists.txt
index fcfca354f4a75..df34a5707da33 100644
--- a/clang/test/CMakeLists.txt
+++ b/clang/test/CMakeLists.txt
@@ -9,6 +9,7 @@ llvm_canonicalize_cmake_booleans(
   CLANG_ENABLE_STATIC_ANALYZER
   CLANG_PLUGIN_SUPPORT
   CLANG_SPAWN_CC1
+  CLANG_ENABLE_CIR
   ENABLE_BACKTRACES
   LLVM_ENABLE_ZLIB
   LLVM_ENABLE_ZSTD
diff --git a/clang/test/lit.site.cfg.py.in b/clang/test/lit.site.cfg.py.in
index ef75770a2c3c9..6641811c58839 100644
--- a/clang/test/lit.site.cfg.py.in
+++ b/clang/test/lit.site.cfg.py.in
@@ -27,6 +27,7 @@ config.clang_default_pie_on_linux = @CLANG_DEFAULT_PIE_ON_LINUX@
 config.clang_default_cxx_stdlib = "@CLANG_DEFAULT_CXX_STDLIB@"
 config.clang_staticanalyzer = @CLANG_ENABLE_STATIC_ANALYZER@
 config.clang_staticanalyzer_z3 = @LLVM_WITH_Z3@
+config.clang_enable_cir = @CLANG_ENABLE_CIR@
 config.clang_examples = @CLANG_BUILD_EXAMPLES@
 config.enable_shared = @ENABLE_SHARED@
 config.enable_backtrace = @ENABLE_BACKTRACES@