diff --git a/include/type.h b/include/type.h
index 3736104..68d10cf 100644
--- a/include/type.h
+++ b/include/type.h
@@ -9,7 +9,7 @@ namespace triton_tvm_ffi {
 
 // --------------- Definitions --------------- //
 
-#define TYPE_TABLE(V)                                                          \
+#define TYPE_TABLE_NATIVE(V)                                                   \
   V(I1, "i1", int8_t)                                                          \
   V(I8, "i8", int8_t)                                                          \
   V(I16, "i16", int16_t)                                                       \
@@ -23,7 +23,10 @@ namespace triton_tvm_ffi {
   V(FP16, "fp16", double)                                                      \
   V(BF16, "bf16", double)                                                      \
   V(FP32, "f32", double)                                                       \
-  V(FP64, "fp64", double)                                                      \
+  V(FP64, "fp64", double)
+
+#define TYPE_TABLE(V)                                                          \
+  TYPE_TABLE_NATIVE(V)                                                         \
   V(PTR, "*?", void *)                                                         \
   V(CONSTEXPR, "constexpr", void)
 
@@ -43,28 +46,6 @@ TYPE_TABLE(DEFINE_TYPE_TO_CTYPE)
 #undef DEFINE_TYPE_TO_CTYPE
 template <Type T> using type_to_ctype_t = typename type_to_ctype<T>::t;
 
-template <typename T, typename = void> struct type_size {
-  static constexpr size_t value = 0;
-};
-template <typename T>
-struct type_size<T, std::enable_if_t<!std::is_void_v<decltype(sizeof(T))>>> {
-  static constexpr size_t value = sizeof(T);
-};
-template <typename T> constexpr size_t type_size_v = type_size<T>::value;
-
-template <size_t... Ns> struct max;
-template <size_t... Ns> constexpr size_t max_v = max<Ns...>::value;
-template <size_t N> struct max<N> { static constexpr size_t value = N; };
-template <size_t N, size_t... Ns> struct max<N, Ns...> {
-  static constexpr size_t value = N > max_v<Ns...> ? N : max_v<Ns...>;
-};
-
-static constexpr size_t kMaxOpaqueSize = max_v<
-#define DEFINE_TYPE_SIZE(type, str, ctype) type_size_v<ctype>,
-    TYPE_TABLE(DEFINE_TYPE_SIZE)
-#undef DEFINE_TYPE_SIZE
-        0>;
-
 // --------------- Implementations --------------- //
 
 } // namespace triton_tvm_ffi
diff --git a/src/utils.cc b/src/utils.cc
index 42aea17..abbc612 100644
--- a/src/utils.cc
+++ b/src/utils.cc
@@ -11,66 +11,11 @@
 
 #define CUDA_CHECK(code)                                                       \
   do {                                                                         \
-    if ((code) != CUDA_SUCCESS) {                                              \
+    if (__builtin_expect((code) != CUDA_SUCCESS, 0)) {                         \
       throw triton_tvm_ffi::CUDAException(code);                               \
     }                                                                          \
   } while (false)
 
-namespace {
-
-using namespace triton_tvm_ffi;
-
-// --------------- Definitions ---------------
-
-template <Type T> struct ValueCast {
-  TRITON_TVM_FFI_INLINE static bool apply(void *ptr, const TypedValue &value);
-};
-
-template <Type... Ts> struct ValueCastSet {
-  TRITON_TVM_FFI_INLINE static bool apply(void *ptr, const TypedValue &value);
-};
-
-using GenericValueCastSet = ValueCastSet<
-#define DEFINE_TYPE_CAST(type, str, ctype) Type::type,
-    TYPE_TABLE(DEFINE_TYPE_CAST)
-#undef DEFINE_TYPE_CAST
-        Type::PTR>;
-
-// --------------- Implementations ---------------
-
-template <Type T>
-TRITON_TVM_FFI_INLINE bool ValueCast<T>::apply(void *ptr,
-                                               const TypedValue &value) {
-  if (value.GetType() == T) {
-    if constexpr (T == Type::PTR) {
-      tvm::ffi::TensorView cvalue =
-          value.GetValue().cast<tvm::ffi::TensorView>();
-      void **p = reinterpret_cast<void **>(ptr);
-      *p = cvalue.data_ptr();
-    } else if constexpr (T == Type::CONSTEXPR) {
-#ifdef NDEBUG
-      __builtin_unreachable();
-#else
-      throw NotImplementedException("CONSTEXPR for value casting");
-#endif
-    } else {
-      using ctype = type_to_ctype_t<T>;
-      ctype cvalue = value.GetValue().cast<ctype>();
-      ctype *p = reinterpret_cast<ctype *>(ptr);
-      *p = cvalue;
-    }
-    return true;
-  }
-  return false;
-}
-template <Type... Ts>
-TRITON_TVM_FFI_INLINE bool ValueCastSet<Ts...>::apply(void *ptr,
-                                                      const TypedValue &value) {
-  return (ValueCast<Ts>::apply(ptr, value) || ...);
-}
-
-} // namespace
-
 namespace triton_tvm_ffi {
 
 tvm::ffi::Map<tvm::ffi::String, int32_t> GetDeviceProperties(int device_id) {
@@ -159,23 +104,40 @@ void Launch(int32_t gridX, int32_t gridY, int32_t gridZ, uint64_t stream,
           cFunction, CU_FUNC_ATTRIBUTE_NON_PORTABLE_CLUSTER_SIZE_ALLOWED, 1));
     }
     const int32_t kernelArgNum = kernelArgs.size();
-    uint8_t *buffer =
-        reinterpret_cast<uint8_t *>(alloca(kMaxOpaqueSize * (kernelArgNum)));
     void **params =
         reinterpret_cast<void **>(alloca(sizeof(void *) * (kernelArgNum + 2)));
     size_t j = 0;
     for (size_t i = 0; i < kernelArgNum; ++i) {
       TypedValue value = kernelArgs[i].cast<TypedValue>();
-      if (value.GetType() != Type::CONSTEXPR) {
-#ifndef NDEBUG
-        assert(j < kernelArgNum);
-#endif
-        void *ptr = buffer + j * kMaxOpaqueSize;
-        params[j] = ptr;
-        if (!GenericValueCastSet::apply(ptr, value)) {
-          throw UnknownTypeException(value.GetType());
-        }
+      switch (value.GetType()) {
+#define CASE_STMT(type, str, ctype)                                            \
+  case Type::type: {                                                           \
+    using cpptype = type_to_ctype_t<Type::type>;                               \
+    params[j] = reinterpret_cast<void *>(alloca(sizeof(cpptype)));             \
+    *reinterpret_cast<cpptype *>(params[j]) =                                  \
+        value.GetValue().cast<cpptype>();                                      \
+    ++j;                                                                       \
+    break;                                                                     \
+  }
+        TYPE_TABLE_NATIVE(CASE_STMT)
+#undef CASE_STMT
+      case Type::PTR: {
+        params[j] = reinterpret_cast<void *>(alloca(sizeof(void *)));
+        *reinterpret_cast<void **>(params[j]) =
+            value.GetValue().cast<tvm::ffi::TensorView>().data_ptr();
         ++j;
+        break;
+      }
+      case Type::CONSTEXPR: {
+        break;
+      }
+      default: {
+#ifdef NDEBUG
+        __builtin_unreachable();
+#else
+        throw NotImplementedException("CONSTEXPR for value casting");
+#endif
+      }
       }
     }
     // TODO: unwrap PyObject* from scratch pointers and assign to kernel args