diff --git a/core/src/index/knowhere/knowhere/index/vector_index/IndexBinaryIDMAP.cpp b/core/src/index/knowhere/knowhere/index/vector_index/IndexBinaryIDMAP.cpp
index d368a06ac9..303ab2d13c 100644
--- a/core/src/index/knowhere/knowhere/index/vector_index/IndexBinaryIDMAP.cpp
+++ b/core/src/index/knowhere/knowhere/index/vector_index/IndexBinaryIDMAP.cpp
@@ -58,7 +58,7 @@ BinaryIDMAP::Query(const DatasetPtr& dataset_ptr, const Config& config) {
     auto ret_ds = std::make_shared<Dataset>();
     if (index_->metric_type == faiss::METRIC_Hamming) {
         auto pf_dist = (float*)malloc(p_dist_size);
-        int32_t* pi_dist = (int32_t*)p_dist;
+        int32_t* pi_dist = reinterpret_cast<int32_t*>(p_dist);
         for (int i = 0; i < elems; i++) {
             *(pf_dist + i) = (float)(*(pi_dist + i));
         }
diff --git a/core/src/index/knowhere/knowhere/index/vector_index/IndexBinaryIVF.cpp b/core/src/index/knowhere/knowhere/index/vector_index/IndexBinaryIVF.cpp
index 33fc722d6a..33a052e588 100644
--- a/core/src/index/knowhere/knowhere/index/vector_index/IndexBinaryIVF.cpp
+++ b/core/src/index/knowhere/knowhere/index/vector_index/IndexBinaryIVF.cpp
@@ -64,7 +64,7 @@ BinaryIVF::Query(const DatasetPtr& dataset_ptr, const Config& config) {
         auto ret_ds = std::make_shared<Dataset>();
         if (index_->metric_type == faiss::METRIC_Hamming) {
             auto pf_dist = (float*)malloc(p_dist_size);
-            int32_t* pi_dist = (int32_t*)p_dist;
+            int32_t* pi_dist = reinterpret_cast<int32_t*>(p_dist);
             for (int i = 0; i < elems; i++) {
                 *(pf_dist + i) = (float)(*(pi_dist + i));
             }
diff --git a/core/src/index/knowhere/knowhere/index/vector_index/IndexNSG.cpp b/core/src/index/knowhere/knowhere/index/vector_index/IndexNSG.cpp
index 4134cd552e..c6f8074a4a 100644
--- a/core/src/index/knowhere/knowhere/index/vector_index/IndexNSG.cpp
+++ b/core/src/index/knowhere/knowhere/index/vector_index/IndexNSG.cpp
@@ -114,9 +114,9 @@ NSG::Train(const DatasetPtr& dataset_ptr, const Config& config) {
     idmap->AddWithoutIds(dataset_ptr, config);
     impl::Graph knng;
     const float* raw_data = idmap->GetRawVectors();
-    const int64_t device_id = config[knowhere::meta::DEVICEID].get<int64_t>();
     const int64_t k = config[IndexParams::knng].get<int64_t>();
 #ifdef MILVUS_GPU_VERSION
+    const int64_t device_id = config[knowhere::meta::DEVICEID].get<int64_t>();
     if (device_id == -1) {
         auto preprocess_index = std::make_shared<IVF>();
         preprocess_index->Train(dataset_ptr, config);
diff --git a/core/src/index/knowhere/knowhere/index/vector_index/VecIndexFactory.cpp b/core/src/index/knowhere/knowhere/index/vector_index/VecIndexFactory.cpp
index f90ba79c9b..05674e9c9e 100644
--- a/core/src/index/knowhere/knowhere/index/vector_index/VecIndexFactory.cpp
+++ b/core/src/index/knowhere/knowhere/index/vector_index/VecIndexFactory.cpp
@@ -47,7 +47,9 @@ namespace knowhere {
 
 VecIndexPtr
 VecIndexFactory::CreateVecIndex(const IndexType& type, const IndexMode mode) {
+#ifdef MILVUS_GPU_VERSION
     auto gpu_device = -1;  // TODO: remove hardcode here, get from invoker
+#endif
     if (type == IndexEnum::INDEX_FAISS_IDMAP) {
         return std::make_shared<knowhere::IDMAP>();
     } else if (type == IndexEnum::INDEX_FAISS_IVFFLAT) {
diff --git a/core/src/index/knowhere/knowhere/index/vector_index/gpu/IndexGPUIVF.cpp b/core/src/index/knowhere/knowhere/index/vector_index/gpu/IndexGPUIVF.cpp
index 5786f63afa..93a5fb62cc 100644
--- a/core/src/index/knowhere/knowhere/index/vector_index/gpu/IndexGPUIVF.cpp
+++ b/core/src/index/knowhere/knowhere/index/vector_index/gpu/IndexGPUIVF.cpp
@@ -53,7 +53,8 @@ GPUIVF::Train(const DatasetPtr& dataset_ptr, const Config& config) {
 
 void
 GPUIVF::Add(const DatasetPtr& dataset_ptr, const Config& config) {
-    if (auto spt = res_.lock()) {
+    auto spt = res_.lock();
+    if (spt != nullptr) {
         ResScope rs(res_, gpu_id_);
         IVF::Add(dataset_ptr, config);
     } else {
@@ -65,7 +66,8 @@ VecIndexPtr
 GPUIVF::CopyGpuToCpu(const Config& config) {
     std::lock_guard<std::mutex> lk(mutex_);
 
-    if (auto device_idx = std::dynamic_pointer_cast<faiss::gpu::GpuIndexIVF>(index_)) {
+    auto device_idx = std::dynamic_pointer_cast<faiss::gpu::GpuIndexIVF>(index_);
+    if (device_idx != nullptr) {
         faiss::Index* device_index = index_.get();
         faiss::Index* host_index = faiss::gpu::index_gpu_to_cpu(device_index);
 
diff --git a/core/src/index/knowhere/knowhere/index/vector_offset_index/gpu/IndexGPUIVF_NM.cpp b/core/src/index/knowhere/knowhere/index/vector_offset_index/gpu/IndexGPUIVF_NM.cpp
index 82be441ceb..ade6bcf152 100644
--- a/core/src/index/knowhere/knowhere/index/vector_offset_index/gpu/IndexGPUIVF_NM.cpp
+++ b/core/src/index/knowhere/knowhere/index/vector_offset_index/gpu/IndexGPUIVF_NM.cpp
@@ -54,7 +54,8 @@ GPUIVF_NM::Train(const DatasetPtr& dataset_ptr, const Config& config) {
 
 void
 GPUIVF_NM::Add(const DatasetPtr& dataset_ptr, const Config& config) {
-    if (auto spt = res_.lock()) {
+    auto spt = res_.lock();
+    if (spt != nullptr) {
         ResScope rs(res_, gpu_id_);
         IVF::Add(dataset_ptr, config);
     } else {
@@ -71,7 +72,8 @@ VecIndexPtr
 GPUIVF_NM::CopyGpuToCpu(const Config& config) {
     std::lock_guard<std::mutex> lk(mutex_);
 
-    if (auto device_idx = std::dynamic_pointer_cast<faiss::gpu::GpuIndexIVF>(index_)) {
+    auto device_idx = std::dynamic_pointer_cast<faiss::gpu::GpuIndexIVF>(index_);
+    if (device_idx != nullptr) {
         faiss::Index* device_index = index_.get();
         faiss::Index* host_index = faiss::gpu::index_gpu_to_cpu_without_codes(device_index);
 
diff --git a/core/src/index/unittest/faiss_benchmark/faiss_benchmark_test.cpp b/core/src/index/unittest/faiss_benchmark/faiss_benchmark_test.cpp
index 8c6649fdb7..c9be654fec 100644
--- a/core/src/index/unittest/faiss_benchmark/faiss_benchmark_test.cpp
+++ b/core/src/index/unittest/faiss_benchmark/faiss_benchmark_test.cpp
@@ -346,11 +346,11 @@ test_with_nprobes(const std::string& ann_test_name, const std::string& index_key
     std::unordered_map<int32_t, std::string> mode_str_map = {
         {MODE_CPU, "MODE_CPU"}, {MODE_MIX, "MODE_MIX"}, {MODE_GPU, "MODE_GPU"}};
 
-    double copy_time = 0.0;
     faiss::Index *gpu_index = nullptr, *index = nullptr;
     if (query_mode != MODE_CPU) {
         faiss::gpu::GpuClonerOptions option;
         option.allInGpu = true;
+        double copy_time = 0.0;
 
         faiss::IndexComposition index_composition;
         index_composition.index = cpu_index;