Propogate dynamo shape_env to make_fx (#96437)

Currently, when we use assume_static_by_default flag, dynamo won't produce any symbols for input tensors. But when we pass the dynamo generated graph onto make_fx via torchdynamo.export(aten_graph=True), there is no way to pass this flag. We enable this by directly passing the fake tensors dynamo used to make_fx and call make_fx with "real" mode with fake tensors from dynamo.

Note that this is modified version of (https://github.com/pytorch/pytorch/pull/96143)

Differential Revision: [D43994693](https://our.internmc.facebook.com/intern/diff/D43994693)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/96437
Approved by: https://github.com/jansel, https://github.com/ezyang

functorch/experimental/_cond.py

@@ -185,6 +185,7 @@ def _has_potential_branch_input_alias(branch, inputs):
     """
     try:
         gm = make_fx(branch)(*inputs)
+
     except UnsupportedAliasMutationException:
         # this can happen when nested cond is
         # functionalized

test/dynamo/test_export.py

@@ -15,7 +15,10 @@ from functorch.experimental.control_flow import cond
 from torch._dynamo import config
 from torch._export import dynamic_dim
 from torch.fx.experimental.proxy_tensor import make_fx
-from torch.fx.experimental.symbolic_shapes import ConstraintViolationError
+from torch.fx.experimental.symbolic_shapes import (
+    ConstraintViolationError,
+    is_concrete_int,
+)
 from torch.testing._internal import common_utils
 
 
@@ -2281,6 +2284,28 @@ class ExportTests(torch._dynamo.test_case.TestCase):
         constraints = [dynamic_dim(y, 0)]
         torch._dynamo.export(my_dyn_fn, y, constraints=constraints)
 
+    @config.patch(assume_static_by_default=True, dynamic_shapes=True)
+    def test_propagate_assume_static_by_default(self):
+        def f(x):
+            if x.shape[0] > 3:
+                return x.sin()
+            return x.cos()
+
+        gm, _ = torch._dynamo.export(
+            f, torch.ones(6, 4), aten_graph=True, tracing_mode="symbolic"
+        )
+
+        for node in gm.graph.nodes:
+            val = node.meta.get("val", None)
+            if val is not None:
+                shapes = val.shape
+                # there should no symbols
+                for shape in shapes:
+                    self.assertTrue(is_concrete_int(shape))
+
+        # this should be captured as static, as export won't generate any symbols.
+        self.assertEqual(gm(torch.ones(2, 4)), torch.ones(2, 4).sin())
+
 
 common_utils.instantiate_parametrized_tests(ExportTests)
 

torch/__init__.py

@@ -32,8 +32,8 @@ from typing import Any, Callable, Dict, Optional, Set, Type, TYPE_CHECKING, Unio
 import builtins
 
 __all__ = [
-    'typename', 'is_tensor', 'is_storage', 'set_default_tensor_type',
-    'set_default_device',
+    'typename', 'is_tensor', 'is_storage',
+    'set_default_tensor_type', 'set_default_device',
     'set_rng_state', 'get_rng_state', 'manual_seed', 'initial_seed', 'seed',
     'save', 'load', 'set_printoptions', 'chunk', 'split', 'stack', 'matmul',
     'no_grad', 'enable_grad', 'rand', 'randn', 'inference_mode',
@@ -49,7 +49,7 @@ __all__ = [
     'set_float32_matmul_precision', 'get_float32_matmul_precision',
     'set_warn_always', 'is_warn_always_enabled', 'SymInt', 'SymFloat',
     'SymBool', 'sym_not',
-    'sym_int', 'sym_float', 'sym_max', 'sym_min', 'compile', 'vmap'
+    'sym_int', 'sym_float', 'sym_max', 'sym_min', 'compile', 'vmap',
 ]
 
 ################################################################################

torch/_dynamo/eval_frame.py

@@ -51,6 +51,8 @@ from .utils import compile_times
 
 log = logging.getLogger(__name__)
 
+from torch._dispatch.python import enable_python_dispatcher
+from torch._subclasses.fake_tensor import FakeTensor
 from torch.fx.experimental import proxy_tensor
 
 always_optimize_code_objects = utils.ExactWeakKeyDictionary()
@@ -635,6 +637,7 @@ def export(
     graph = None
     out_guards = None
     graph_captured_input = None
+    example_fake_inputs = []
     graph_captured_result: Optional[Tuple[torch.Tensor, ...]] = None
 
     def produce_matching(source_args, candidate_args):
@@ -680,6 +683,9 @@ def export(
         ), "Tried to emit a second graph during export. Tracing through 'f' must produce a single graph."
         graph = gm
 
+        nonlocal example_fake_inputs
+        example_fake_inputs = example_inputs
+
         def result_capturing_wrapper(*graph_inputs):
             nonlocal graph_captured_result
             nonlocal graph_captured_input
@@ -699,7 +705,10 @@ def export(
     ):
         opt_f = optimize_assert(
             dynamo_normalization_capturing_compiler,
-            hooks=Hooks(guard_export_fn=guard_export_print, guard_fail_fn=None),
+            hooks=Hooks(
+                guard_export_fn=guard_export_print,
+                guard_fail_fn=None,
+            ),
             export=True,
             export_constraints=constraints,
             dynamic=(tracing_mode == "symbolic"),
@@ -763,12 +772,19 @@ def export(
             with torch.fx.traceback.preserve_node_meta():
                 return torch.fx.Interpreter(graph).run(*args)
 
-        graph = make_fx(
-            graph_with_interpreter,
-            decomposition_table=decomposition_table,
-            tracing_mode=tracing_mode,
-            _allow_non_fake_inputs=True,
-        )(*graph_captured_input)
+        fake_tensor_mode = null_context()
+        for val in example_fake_inputs:
+            if isinstance(val, FakeTensor):
+                fake_tensor_mode = val.fake_mode
+                break
+
+        with enable_python_dispatcher(), fake_tensor_mode:
+            graph = make_fx(
+                graph_with_interpreter,
+                decomposition_table=decomposition_table,
+                tracing_mode="real",
+                _allow_non_fake_inputs=True,
+            )(*example_fake_inputs)
 
     new_graph = ChangeInputOutputSignature(
         graph,

torch/_dynamo/output_graph.py

@@ -203,6 +203,8 @@ class OutputGraph(fx.Tracer, Checkpointable[OutputGraphState]):
             )
             if config.dynamic_shapes
             else None,
+            # TODO (tmanlaibaatar) Remove this once we always lift params and buffers
+            allow_non_fake_inputs=True if self.export else False,
         )
         self.tracing_context: TracingContext = TracingContext(fake_mode)
         if config.dynamic_shapes:

torch/ao/quantization/_pt2e/utils.py

@@ -17,7 +17,7 @@ def _get_tensor_constant_from_node(node, m):
 # fuse conv bn weights, inplace modification of the graph_module and graph
 def _fuse_conv_bn_(m: GraphModule) -> None:
     for n in m.graph.nodes:
-        if n.op != "call_function" or n.target != torch.ops.aten.native_batch_norm.default:
+        if n.op != "call_function" or n.target != torch.ops.aten._native_batch_norm_legit_no_training.default:
             continue
         bn_op = n
         n = bn_op.args[0]
@@ -39,7 +39,7 @@ def _fuse_conv_bn_(m: GraphModule) -> None:
         bn_rm = _get_tensor_constant_from_node(bn_op.args[3], m)
         # bn running variance
         bn_rv = _get_tensor_constant_from_node(bn_op.args[4], m)
-        bn_eps = bn_op.args[7]
+        bn_eps = bn_op.args[6]
 
         fused_weight, fused_bias = fuse_conv_bn_weights(conv_w, conv_b, bn_rm, bn_rv, bn_eps, bn_w, bn_b, transpose=False)
 

torch/fx/experimental/proxy_tensor.py

@@ -20,7 +20,12 @@ import weakref
 import operator
 from torch.utils._stats import count
 
-from torch.utils._python_dispatch import TorchDispatchMode, _pop_mode_temporarily, _get_current_dispatch_mode
+from torch.utils._python_dispatch import (
+    TorchDispatchMode,
+    _pop_mode_temporarily,
+    _get_current_dispatch_mode,
+)
+
 from torch._subclasses import FakeTensor
 from .symbolic_shapes import ShapeEnv, SymDispatchMode, SymNode
 from torch.fx import Proxy

torch/fx/experimental/symbolic_shapes.py

@@ -47,7 +47,7 @@ from sympy.core.logic import fuzzy_and, fuzzy_or
 aten = torch._ops.ops.aten  # type: ignore[has-type]
 
 __all__ = [
-    "has_symbolic_sizes_strides", "create_contiguous", "ShapeEnv",
+    "has_symbolic_sizes_strides", "create_contiguous", "ShapeEnv", "is_concrete_int",
     "SymDispatchMode", "FloorDiv", "guard_int", "guard_float", "guard_scalar", "wrap_node",
     "method_to_operator", "hint_int", "SYMPY_INTERP",
 ]
@@ -128,6 +128,24 @@ def has_hint(a):
         return a.node.has_hint()
     return True
 
+def is_concrete_int(a: Union[int, SymInt]):
+    r""" Utility to check if underlying object
+    in SymInt is concrete value. Also returns
+    true if integer is passed in.
+
+    Args:
+        a (SymInt or int): Object to test if it int
+    """
+    assert isinstance(a, SymInt) or isinstance(a, int)
+
+    if isinstance(a, int):
+        return True
+
+    if isinstance(a.node.expr, sympy.core.numbers.Integer):
+        return True
+
+    return False
+
 # Returns True if every size dim on the tensor has a hint
 # TODO: Should this include strides too?  For now it doesn't matter,
 # that's quite an obscure case