[Unity] Alter op impl handling empty transform for output

src/relax/transform/alter_op_impl.cc

@@ -324,6 +324,7 @@ class AlterOpImplMutator : public ExprMutator {
 
   /*! \brief Returns the TensorStructInfo after applying the \p transform on its shape */
   StructInfo UpdateStructInfo(const TensorStructInfo& tensor_sinfo, const IndexMap& transform) {
+    if (transform.get() == nullptr) return tensor_sinfo;
     auto shape = GetShapeFromTensorStructInfo(tensor_sinfo);
     arith::Analyzer analyzer;
     auto new_shape = transform->MapShape(shape, &analyzer);

tests/python/relax/test_transform_alter_op_impl.py

@@ -472,5 +472,105 @@ def add_2d(arg0: T.Buffer((4, 4), "float32"), arg1: T.Buffer((4, 4), "float32"),
     )
 
 
+def test_reshape():
+    @I.ir_module
+    class Before:
+        @T.prim_func(private=True)
+        def reshape(
+            A: T.Buffer((T.int64(850), T.int64(2048)), "float16"),
+            T_reshape: T.Buffer((T.int64(850), T.int64(1), T.int64(2048)), "float16"),
+        ):
+            T.func_attr({"operator_name": "relax.reshape"})
+            for ax0, ax1, ax2 in T.grid(T.int64(850), T.int64(1), T.int64(2048)):
+                with T.block("T_reshape"):
+                    v_ax0, v_ax1, v_ax2 = T.axis.remap("SSS", [ax0, ax1, ax2])
+                    T.reads(
+                        A[
+                            (v_ax2 // T.int64(2048) + v_ax0 + v_ax1) % T.int64(850),
+                            v_ax2 % T.int64(2048),
+                        ]
+                    )
+                    T.writes(T_reshape[v_ax0, v_ax1, v_ax2])
+                    T_reshape[v_ax0, v_ax1, v_ax2] = A[
+                        (v_ax2 // T.int64(2048) + v_ax0 + v_ax1) % T.int64(850),
+                        v_ax2 % T.int64(2048),
+                    ]
+
+        @R.function
+        def main(
+            x: R.Tensor((850, 2048), dtype="float16")
+        ) -> R.Tensor((850, 1, 2048), dtype="float16"):
+            cls = Before
+            with R.dataflow():
+                lv = R.call_tir(
+                    cls.reshape, (x,), out_sinfo=R.Tensor((850, 1, 2048), dtype="float16")
+                )
+                gv: R.Tensor((850, 1, 2048), dtype="float16") = lv
+                R.output(gv)
+            return gv
+
+    @I.ir_module
+    class Expected:
+        @T.prim_func(private=True)
+        def relax_reshape_replacement(
+            A: T.Buffer((T.int64(850), T.int64(2), T.int64(1024)), "float16"),
+            T_reshape: T.Buffer((T.int64(850), T.int64(1), T.int64(2048)), "float16"),
+        ):
+            T.func_attr({"operator_name": "relax.reshape"})
+            for ax0, ax1, ax2 in T.grid(T.int64(850), T.int64(1), T.int64(2048)):
+                with T.block("T_reshape"):
+                    v_ax0, v_ax1, v_ax2 = T.axis.remap("SSS", [ax0, ax1, ax2])
+                    T.reads(A[v_ax0, v_ax2 // T.int64(1024), v_ax2 % T.int64(1024)])
+                    T.writes(T_reshape[v_ax0, v_ax1, v_ax2])
+                    T_reshape[v_ax0, v_ax1, v_ax2] = A[
+                        v_ax0, v_ax2 // T.int64(1024), v_ax2 % T.int64(1024)
+                    ]
+
+        @R.function
+        def main(
+            x: R.Tensor((850, 2048), dtype="float16")
+        ) -> R.Tensor((850, 1, 2048), dtype="float16"):
+            cls = Expected
+            with R.dataflow():
+                lv: R.Tensor((850, 2, 1024), dtype="float16") = R.layout_transform(
+                    x,
+                    index_map=T.index_map(lambda i, j: (i, j // 1024, j % 1024)),
+                    pad_value=None,
+                    axis_separators=[],
+                )
+                lv_1 = R.call_tir(
+                    cls.relax_reshape_replacement,
+                    (lv,),
+                    out_sinfo=R.Tensor((850, 1, 2048), dtype="float16"),
+                )
+                gv: R.Tensor((850, 1, 2048), dtype="float16") = lv_1
+                R.output(gv)
+            return gv
+
+    @T.prim_func(private=True)
+    def reshape_new(
+        A: T.Buffer((T.int64(850), T.int64(2), T.int64(1024)), "float16"),
+        T_reshape: T.Buffer((T.int64(850), T.int64(1), T.int64(2048)), "float16"),
+    ):
+        for ax0, ax1, ax2 in T.grid(T.int64(850), T.int64(1), T.int64(2048)):
+            with T.block("T_reshape"):
+                v_ax0, v_ax1, v_ax2 = T.axis.remap("SSS", [ax0, ax1, ax2])
+                T.reads(A[v_ax0, v_ax2 // T.int64(1024), v_ax2 % T.int64(1024)])
+                T.writes(T_reshape[v_ax0, v_ax1, v_ax2])
+                T_reshape[v_ax0, v_ax1, v_ax2] = A[
+                    v_ax0, v_ax2 // T.int64(1024), v_ax2 % T.int64(1024)
+                ]
+
+    # fmt: on
+    index_map = lambda i, j: (i, j // 1024, j % 1024)
+    _check(
+        Before,
+        Expected,
+        operator_name="relax.reshape",
+        replacement_primfunc=reshape_new,
+        layout_changes=[index_map, None],
+    )
+
+
 if __name__ == "__main__":
     tvm.testing.main()