guard_size_oblivious in unbind (#124959)

Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: #124959
Approved by: https://github.com/albanD

torch/_refs/__init__.py

@@ -3890,12 +3890,14 @@ def unflatten(a: TensorLikeType, dim: int, sizes: ShapeType) -> TensorLikeType:
 
 @register_decomposition(aten.unbind)
 def unbind(t: TensorLikeType, dim: int = 0) -> TensorSequenceType:
+    from torch.fx.experimental.symbolic_shapes import guard_size_oblivious
+
     dim = utils.canonicalize_dim(t.ndim, dim)
     torch._check_index(
         len(t.shape) > 0,
         lambda: "Dimension specified as 0 but tensor has no dimensions",
     )
-    if t.shape[dim] == 0:
+    if guard_size_oblivious(t.shape[dim] == 0):
         return tuple()
     else:
         return tuple(