[Misc] Fix build warnings (#5303)

Co-authored-by: songqing.zhang <songqing.zhang@shopee.com>

src/array/cpu/spmm.h

@@ -130,7 +130,6 @@ void SpMMSumCsr(
   const IdType* edges = csr.data.Ptr<IdType>();
   const DType* X = ufeat.Ptr<DType>();
   const DType* W = efeat.Ptr<DType>();
-  int64_t dim = bcast.out_len;
   DType* O = out.Ptr<DType>();
   CHECK_NOTNULL(indptr);
   CHECK_NOTNULL(O);
@@ -160,7 +159,7 @@ void SpMMSumCsr(
     ElemWiseUpd* cpu_spec = (asm_kernel_ptr && asm_kernel_ptr->applicable())
                                 ? asm_kernel_ptr.get()
                                 : nullptr;
-    if (cpu_spec && dim > 16 && !bcast.use_bcast) {
+    if (cpu_spec && bcast.out_len > 16 && !bcast.use_bcast) {
       SpMMSumCsrXbyak<IdType, DType, Op>(cpu_spec, bcast, csr, X, W, O);
     } else {
 #endif  // USE_AVX

src/array/libra_partition.cc

@@ -41,6 +41,7 @@ int32_t Ver2partition(IdType in_val, int64_t *node_map, int32_t num_parts) {
     pos = pos + 1;
   }
   LOG(FATAL) << "Error: Unexpected output in Ver2partition!";
+  return -1;
 }
 
 /**

src/partition/ndarray_partition.cc

@@ -183,11 +183,13 @@ class RangePartition : public NDArrayPartition {
                                   << ") for "
                                      "partition of size "
                                   << NumParts() << ".";
+    int64_t part_size = -1;
     ATEN_ID_TYPE_SWITCH(range_cpu_->dtype, RangeType, {
       const RangeType* const ptr =
           static_cast<const RangeType*>(range_cpu_->data);
-      return ptr[part_id + 1] - ptr[part_id];
+      part_size = ptr[part_id + 1] - ptr[part_id];
     });
+    return part_size;
   }
 
  private:

tests/dist/cpp/rpc_client.cc

@@ -47,7 +47,6 @@ class RPCClient {
         ++recv_id;
       }
     }
-    const int num_machines = ips_.size();
     for (int i = 0; i < kNumMessage; ++i) {
       for (int n = 0; n < recv_id; ++n) {
         dgl::rpc::RPCMessage msg;