[mesh] Fix MeshTaichi warnings in CUDA backend (#6369)

continue from: #6306

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

taichi/transforms/make_mesh_block_local.cpp

@@ -207,8 +207,11 @@ Stmt *MakeMeshBlockLocal::create_cache_mapping(
     Stmt *bls_ptr = body->push_back<BlockLocalPtrStmt>(
         offset,
         TypeFactory::get_instance().get_pointer_type(mapping_data_type_));
+    Stmt *casted_val = body->push_back<UnaryOpStmt>(UnaryOpType::cast_value,
+                                                    global_val(body, idx_val));
+    casted_val->as<UnaryOpStmt>()->cast_type = PrimitiveType::i32;
     [[maybe_unused]] Stmt *bls_store =
-        body->push_back<GlobalStoreStmt>(bls_ptr, global_val(body, idx_val));
+        body->push_back<GlobalStoreStmt>(bls_ptr, casted_val);
   });
 }
 
@@ -368,8 +371,11 @@ void MakeMeshBlockLocal::fetch_mapping(
           Stmt *global_ptr = body->push_back<GlobalPtrStmt>(
               mapping_snode_, std::vector<Stmt *>{global_offset});
           Stmt *global_load = body->push_back<GlobalLoadStmt>(global_ptr);
-          attr_callback_handler(body, idx_val, global_load);
-          return global_load;
+          Stmt *casted_global_load = body->push_back<UnaryOpStmt>(
+              UnaryOpType::cast_value, global_load);
+          casted_global_load->as<UnaryOpStmt>()->cast_type = PrimitiveType::i32;
+          attr_callback_handler(body, idx_val, casted_global_load);
+          return casted_global_load;
         });
   } else {
     // int i = threadIdx.x;
@@ -388,8 +394,11 @@ void MakeMeshBlockLocal::fetch_mapping(
           Stmt *global_ptr = body->push_back<GlobalPtrStmt>(
               mapping_snode_, std::vector<Stmt *>{global_offset});
           Stmt *global_load = body->push_back<GlobalLoadStmt>(global_ptr);
-          attr_callback_handler(body, idx_val, global_load);
-          return global_load;
+          Stmt *casted_global_load = body->push_back<UnaryOpStmt>(
+              UnaryOpType::cast_value, global_load);
+          casted_global_load->as<UnaryOpStmt>()->cast_type = PrimitiveType::i32;
+          attr_callback_handler(body, idx_val, casted_global_load);
+          return casted_global_load;
         });
   }
 }
@@ -513,7 +522,8 @@ MakeMeshBlockLocal::MakeMeshBlockLocal(OffloadedStmt *offload,
     mapping_snode_ = (offload->mesh->index_mapping
                           .find(std::make_pair(element_type, conv_type))
                           ->second);
-    mapping_data_type_ = mapping_snode_->dt.ptr_removed();
+    // mapping_data_type_ = mapping_snode_->dt.ptr_removed();
+    mapping_data_type_ = PrimitiveType::i32;
     mapping_dtype_size_ = data_type_size(mapping_data_type_);
 
     // Ensure BLS alignment