primspec for concat
diff --git a/torch/autograd/_functions/tensor.py b/torch/autograd/_functions/tensor.py
index dee17f0..1c214ba 100644
--- a/torch/autograd/_functions/tensor.py
+++ b/torch/autograd/_functions/tensor.py
@@ -320,6 +320,10 @@
 class Concat(Function):
 
     @staticmethod
+    def primspec(dim, *inputs):
+        return torch.toffee.op("Concat", inputs, axis=dim)
+
+    @staticmethod
     def forward(ctx, dim, *inputs):
         ctx.dim = dim
         ctx.input_sizes = [i.size(dim) for i in inputs]