[torch-mlir][sparse] add a COO test for 3-dim (#3119)

This tests COO for more than 2-dim. Note that sparsity should really
propagate into the relu activation and the output, but such cleverness
needs to wait for the pending work in the PyTorch tree.

test/python/fx_importer/sparse_test.py

@@ -48,8 +48,8 @@ def sparse_metadata(a: torch.Tensor) -> SparsityMeta:
             sparse_dim,
             dense_dim,
             blocksize,
-            a.indices().dtype,
-            a.indices().dtype,
+            a._indices().dtype,
+            a._indices().dtype,
         )
     elif a.layout is torch.sparse_csr or a.layout is torch.sparse_bsr:
         if a.layout is torch.sparse_bsr:
@@ -373,3 +373,34 @@ def test_sparse_eltwise():
     print(res2)
     print("torch.mlir.batch")
     print(res3)
+
+
+@run
+# CHECK-LABEL: test_sparse_coo3
+# CHECK:       #[[$COO3:.*]] = #sparse_tensor.encoding<{ map = (d0, d1, d2) -> (d0 : compressed(nonunique), d1 : singleton(nonunique, soa), d2 : singleton(soa)), posWidth = 64, crdWidth = 64 }>
+# CHECK:       func.func @main(
+# CHECK-SAME:    %[[A:.*]]: !torch.vtensor<[10,20,30],f64,#sparse>) -> !torch.vtensor<[10,20,30],f64> {
+# CHECK:         %[[R:.*]] = torch.aten.relu %[[A]] : !torch.vtensor<[10,20,30],f64,#sparse> -> !torch.vtensor<[10,20,30],f64>
+# CHECK:         return %[[R]] : !torch.vtensor<[10,20,30],f64>
+# CHECK:       }
+#
+# TODO: make sure sparsity propagates through relu into the output and test actual JIT output
+#
+def test_sparse_coo3():
+    class COO3Net(torch.nn.Module):
+        def __init__(self):
+            super(COO3Net, self).__init__()
+            self.relu = nn.ReLU()
+
+        def forward(self, x):
+            return self.relu(x)
+
+    net = COO3Net()
+
+    # Direct 3-dim COO construction.
+    idx = torch.tensor([[0, 1, 1, 4, 9, 9], [0, 1, 1, 5, 19, 19], [0, 1, 3, 6, 28, 29]])
+    val = torch.tensor([-1000.0, -1.0, 1.0, 2.0, 3.0, 1000.0], dtype=torch.float64)
+    sparse_input = torch.sparse_coo_tensor(idx, val, size=[10, 20, 30])
+
+    m = export_and_import(net, sparse_input)
+    print(m)