Fix concat with transposed inputs

src/targets/gpu/device/concat.cpp

@@ -20,10 +20,12 @@ argument concat(hipStream_t stream,
         auto&& arg            = args[j];
         std::size_t nelements = arg.get_shape().elements();
         auto offset           = offsets[j];
-        hip_visit_all(args.back(), arg)([&](auto output, auto input) {
+        shape arg_shape{arg.get_shape().type(), arg.get_shape().lens()};
+        hip_visit_all(args.back(), arg, arg_shape)([&](auto output, auto input, auto input_shape) {
             gs_launch(stream, nelements)([=](auto i) {
-                auto idx                    = output.get_shape().index(input.get_shape().multi(i));
-                output.data()[idx + offset] = input.data()[i];
+                auto input_idx = input_shape.multi(i);
+                auto idx                    = output.get_shape().index(input_idx);
+                output.data()[idx + offset] = input[input_idx];
             });
         });
     }