[TVMScript][TIR] Parse subroutine calls with no arguments

python/tvm/script/parser/tir/parser.py

@@ -406,13 +406,25 @@ def visit_expr_stmt(self: Parser, node: doc.Expr) -> None:
         The doc AST Expr node.
     """
     res = self.eval_expr(node.value)
-    if isinstance(res, Frame):
+    if res is None:
+        pass
+    elif isinstance(res, Frame):
         res.add_callback(partial(res.__exit__, None, None, None))
         res.__enter__()
     elif isinstance(res, PrimExpr):
         T.evaluate(res)
     elif isinstance(res, (int, bool)):
         T.evaluate(tvm.tir.const(res))
+    elif isinstance(res, tvm.relay.Call) and not res.args:
+        # Using GlobalVar.__call__ with no arguments is ambiguous, as
+        # each IR has a different function Call representation.  If
+        # this occurs, convert to the TIR representation.
+        T.evaluate(tvm.tir.call_tir(res.op))
+    elif isinstance(res, str):
+        # Ignore docstrings
+        pass
+    else:
+        self.report_error(node, f"Parsing resulted in unexpected type {type(res)}")
 
 
 @dispatch.register(token="tir", type_name="If")

tests/python/unittest/test_tvmscript_roundtrip.py

@@ -3855,6 +3855,24 @@ def func():
     return func
 
 
+def subroutine_call_without_arguments():
+    @I.ir_module
+    class mod:
+        @T.prim_func
+        def main():
+            # Should be equivalent to the bare "mod.subroutine()", but
+            # that relies on `GlobalVar.__call__` returning the
+            # correct IR type.  Previously, this instead returned a
+            # `relay.Call` object.
+            tir.call_tir(mod.subroutine)
+
+        @T.prim_func
+        def subroutine():
+            T.evaluate(0)
+
+    return mod
+
+
 ir_generator = tvm.testing.parameter(
     launch_env_thread,
     opt_gemm_normalize,
@@ -3929,6 +3947,7 @@ def func():
     undefined_shape_in_decl_buffer,
     undefined_stride_in_decl_buffer,
     undefined_elem_offset_in_decl_buffer,
+    subroutine_call_without_arguments,
 )