fix(dnn): fix opencl algo search

GitOrigin-RevId: 25997d0ef1

dnn/include/megdnn/oprs/base.h

@@ -155,7 +155,15 @@ public:
 
     template <typename T>
     static T deserialize_read_pod(const std::string& data, size_t offset = 0) {
-        T ret = *reinterpret_cast<const T*>(&data[offset]);
+        T ret;
+        //! A pointer to an object or incomplete type may be converted to a
+        //! pointer to a different object or incomplete type. If the resulting
+        //! pointer is not correctly aligned for the pointed-to type, the
+        //! behavior is undefined.
+        //!
+        //! so here we should use memcpy instead of
+        //!     *reinterpret_cast<const T*>(&data[offset]);
+        memcpy(&ret, data.data() + offset, sizeof(T));
         return ret;
     }
 

dnn/src/common/algo_chooser.h

@@ -48,10 +48,10 @@ typename Opr::AlgoBase* get_algorithm_or_construct(Opr* opr, Args&&... args) {
     if (set.valid()) {
         return opr->algo_pack().construct_and_get_algo(set.desc);
     } else {
-        ret = opr->get_algorithm_info_heuristic(
-                std::forward<Args>(args)..., std::numeric_limits<size_t>::max(),
-                false);
-        return opr->get_algo_from_desc(ret.desc);
+        return static_cast<typename Opr::AlgoBase*>(
+                opr->get_algorithm_heuristic(std::forward<Args>(args)...,
+                                             std::numeric_limits<size_t>::max(),
+                                             false));
     }
 }