diff --git a/.ci/monolithic-windows.sh b/.ci/monolithic-windows.sh
index 219979dd3e36e..5fb8f69528e89 100755
--- a/.ci/monolithic-windows.sh
+++ b/.ci/monolithic-windows.sh
@@ -23,8 +23,8 @@ runtimes_targets="${4}"
 start-group "CMake"
 pip install -q -r "${MONOREPO_ROOT}"/.ci/all_requirements.txt
 
-export CC=cl
-export CXX=cl
+export CC=C:/clang/clang-msvc/bin/clang-cl.exe
+export CXX=C:/clang/clang-msvc/bin/clang-cl.exe
 export LD=link
 
 # The CMAKE_*_LINKER_FLAGS to disable the manifest come from research
@@ -49,6 +49,7 @@ cmake -S "${MONOREPO_ROOT}"/llvm -B "${BUILD_DIR}" \
       -D CMAKE_EXE_LINKER_FLAGS="/MANIFEST:NO" \
       -D CMAKE_MODULE_LINKER_FLAGS="/MANIFEST:NO" \
       -D CMAKE_SHARED_LINKER_FLAGS="/MANIFEST:NO" \
+      -D CMAKE_CXX_FLAGS="-Wno-c++98-compat -Wno-c++14-compat -Wno-unsafe-buffer-usage -Wno-old-style-cast" \
       -D LLVM_ENABLE_RUNTIMES="${runtimes}"
 
 start-group "ninja"