Revert changes to LiftConstantsToInitializersPass

src/onnx_ir/passes/common/constant_manipulation.py

@@ -139,35 +139,11 @@ class LiftSubgraphInitializersToMainGraphPass(ir.passes.InPlacePass):
     for further processing or optimization.
 
     Initializers that are also graph inputs will not be lifted.
-
-    Preconditions:
-        - All initializers in the model must have unique names across the main graph and subgraphs.
     """
 
-    def requires(self, model: ir.Model) -> None:
-        """Ensure all initializer names are unique."""
-        registered_initializer_names: set[str] = set()
-        duplicated_initializers: list[ir.Value] = []
-        for graph in model.graphs():
-            for initializer in graph.initializers.values():
-                if initializer.name is None:
-                    raise ir.passes.PreconditionError(
-                        f"Initializer name is None. Please ensure all initializers have unique names: {initializer!r}"
-                    )
-                if initializer.name in registered_initializer_names:
-                    duplicated_initializers.append(initializer)
-                else:
-                    registered_initializer_names.add(initializer.name)
-        if duplicated_initializers:
-            raise ir.passes.PreconditionError(
-                "Found duplicated initializers in the model. "
-                "Initializer name must be unique across the main graph and subgraphs. "
-                "Please ensure all initializers have unique names. Duplicated: "
-                f"{duplicated_initializers!r}"
-            )
-
     def call(self, model: ir.Model) -> ir.passes.PassResult:
         count = 0
+        registered_initializer_names: dict[str, int] = {}
         for graph in model.graphs():
             if graph is model.graph:
                 continue
@@ -182,6 +158,15 @@ def call(self, model: ir.Model) -> ir.passes.PassResult:
                     continue
                 # Remove the initializer from the subgraph
                 graph.initializers.pop(name)
+                # To avoid name conflicts, we need to rename the initializer
+                # to a unique name in the main graph
+                if name in registered_initializer_names:
+                    name_count = registered_initializer_names[name]
+                    initializer.name = f"{name}_{name_count}"
+                    registered_initializer_names[name] = name_count + 1
+                else:
+                    assert initializer.name is not None
+                    registered_initializer_names[initializer.name] = 1
                 model.graph.register_initializer(initializer)
                 count += 1
                 logger.debug(

src/onnx_ir/passes/common/constant_manipulation_test.py

@@ -311,13 +311,6 @@ def test_pass_with_lifting_constants_to_initializers_within_subgraph(
             graph=main_graph,
             ir_version=10,
         )
-        if then_initializer_name == else_initializer_name:
-            with self.assertRaisesRegex(
-                ir.passes.PreconditionError,
-                "Initializer name must be unique across the main graph and subgraphs",
-            ):
-                constant_manipulation.LiftSubgraphInitializersToMainGraphPass()(model)
-            return
         result = constant_manipulation.LiftSubgraphInitializersToMainGraphPass()(model)
         self.assertTrue(result.modified)
 
@@ -397,13 +390,6 @@ def test_pass_does_not_lift_initialized_inputs_in_subgraph(
             graph=main_graph,
             ir_version=10,
         )
-        if then_initializer_name == else_initializer_name:
-            with self.assertRaisesRegex(
-                ir.passes.PreconditionError,
-                "Initializer name must be unique across the main graph and subgraphs",
-            ):
-                constant_manipulation.LiftSubgraphInitializersToMainGraphPass()(model)
-            return
         result = constant_manipulation.LiftSubgraphInitializersToMainGraphPass()(model)
         self.assertTrue(result.modified)