diff --git a/build_tools/ci/build_posix.sh b/build_tools/ci/build_posix.sh
index f3cdf86d9a57e..b370d0ba80b83 100755
--- a/build_tools/ci/build_posix.sh
+++ b/build_tools/ci/build_posix.sh
@@ -23,8 +23,6 @@ python="$(which python)"
 echo "Using python: $python"
 
 export CMAKE_TOOLCHAIN_FILE="$this_dir/linux_default_toolchain.cmake"
-export CC=clang
-export CXX=clang++
 
 cd $repo_root
 
@@ -32,17 +30,12 @@ echo "::group::CMake configure"
 cmake -S "$repo_root/externals/llvm-project/llvm" -B "$build_dir" \
   -GNinja \
   -DCMAKE_BUILD_TYPE=Release \
-  -DPython3_EXECUTABLE="$(which python)" \
-  -DLLVM_ENABLE_ASSERTIONS=ON \
-  -DTORCH_MLIR_ENABLE_WERROR_FLAG=ON \
-  -DCMAKE_INSTALL_PREFIX="$install_dir" \
-  -DCMAKE_INSTALL_LIBDIR=lib \
+  -DPython3_FIND_VIRTUALENV=ONLY \
   -DLLVM_ENABLE_PROJECTS=mlir \
   -DLLVM_EXTERNAL_PROJECTS="torch-mlir" \
-  -DLLVM_EXTERNAL_TORCH_MLIR_SOURCE_DIR="$repo_root" \
-  -DLLVM_TARGETS_TO_BUILD=host \
+  -DLLVM_EXTERNAL_TORCH_MLIR_SOURCE_DIR="$PWD" \
   -DMLIR_ENABLE_BINDINGS_PYTHON=ON \
-  -DTORCH_MLIR_ENABLE_LTC=ON
+  -DLLVM_TARGETS_TO_BUILD=host
 echo "::endgroup::"
 
 echo "::group::Build"