[torchlib] Add torchlib operator for glu (#1695)

Fix #1665

---------

Co-authored-by: Justin Chu <[email protected]>

Author: shubhambhokare1

onnxscript/function_libs/torch_lib/ops/nn.py

@@ -565,10 +565,13 @@ def aten_gelu_backward(
     raise NotImplementedError()
 
 
-def aten_glu(self: TensorType, dim: int = -1) -> TensorType:
+@torch_op("aten::glu", traceable=True)
+def aten_glu(self: TFloat, dim: int = -1) -> TFloat:
     """glu(Tensor self, int dim=-1) -> Tensor"""
 
-    raise NotImplementedError()
+    first, second = op.Split(self, axis=dim, num_outputs=2)
+    result = op.Mul(first, op.Sigmoid(second))
+    return result
 
 
 def aten_glu_backward(grad_output: TensorType, self: TensorType, dim: int) -> TensorType:

tests/function_libs/torch_lib/ops_test_data.py

@@ -1868,6 +1868,7 @@ def _where_input_wrangler(
         nn_ops.aten_gelu,
         tolerance={torch.float16: (8e-2, 1e-4)},
     ),
+    TorchLibOpInfo("nn.functional.glu", nn_ops.aten_glu),
     TorchLibOpInfo("nn.functional.linear", nn_ops.aten_linear).skip(
         # input: input, args: weight, bias; so len(args) == 2 means bias is provided
         matcher=lambda sample: len(sample.args) != 1,