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Summary: Do not fold torchbind objects in constant folding Any operation on these torchbind objects can have arbitrary side effects, so we can't effectively constant fold anything torchbind-obj-related anyway. Test Plan: ``` buck run fbcode//mode/dev-nosan //caffe2/test/inductor:torchbind -- -r aot_compile_constant_folding ``` Reviewed By: angelayi Differential Revision: D69946541 Pull Request resolved: https://github.com/pytorch/pytorch/pull/148993 Approved by: https://github.com/angelayi
401 lines
14 KiB
Python
401 lines
14 KiB
Python
import collections
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from typing import Any, Callable, Optional
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import torch
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import torch.utils._pytree as pytree
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from torch._inductor.freezing_utils import maybe_set_is_frozen_param
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from torch.utils._ordered_set import OrderedSet
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aten = torch.ops.aten
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# We would like to split modules into two subgraphs for runtime weight updates to work correctly.
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# The use case and more information could be found at:
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# https://docs.google.com/document/d/1inZC-8KarJ6gKB7G9egmYLx1V_dKX_apxon0w4zPC0Q/edit?usp=sharing
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META_TAG = "MODULE_TYPE"
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MODULE_TAG = "_MAIN_MODULE"
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CONST_MODULE_TAG = "_CONST_MODULE"
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def replace_node_with_constant(
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gm: torch.fx.GraphModule,
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node: torch.fx.Node,
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constant: Optional[torch.Tensor] = None,
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name: Optional[str] = None,
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) -> None:
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g = gm.graph
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if name:
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qualname = name
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else:
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if not hasattr(gm, "_frozen_param_count"):
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gm._frozen_param_count = 0 # type: ignore[assignment]
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i = gm._frozen_param_count
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while True:
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qualname = f"_frozen_param{i}"
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if not hasattr(gm, qualname):
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break
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i += 1 # type: ignore[assignment, operator]
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gm._frozen_param_count = i + 1 # type: ignore[assignment, operator]
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with g.inserting_before(node):
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if constant is not None:
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new_input_node = g.create_node("get_attr", qualname, (), {})
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else:
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# this is the case for lifted constants
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new_input_node = g.create_node("placeholder", qualname, (), {})
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node.replace_all_uses_with(new_input_node)
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new_input_node.meta.update(node.meta)
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g.erase_node(node)
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new_input_node.name = node.name
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if constant is not None:
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# needed to suppress `does not reference an nn.Module, nn.Parameter, or buffer` warning
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gm.register_buffer(qualname, constant)
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setattr(gm, qualname, constant)
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# mark any constants created during freezing
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maybe_set_is_frozen_param(constant)
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def is_const_source(
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node: torch.fx.Node, lifted_constant_names: Optional[list[str]]
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) -> bool:
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return node.op == "get_attr" or node.name in (lifted_constant_names or ())
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class ConstantFolder(torch.fx.Interpreter):
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def __init__(
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self,
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gm: torch.fx.GraphModule,
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skip_constructors: bool = False,
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lifted_constant_names: Optional[list[str]] = None,
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skip_folding_node_fn: Optional[Callable[[torch.fx.Node], bool]] = None,
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) -> None:
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super().__init__(gm)
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self.node_replacements: dict[torch.fx.Node, Any] = {}
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self.replaced_uses: dict[torch.fx.Node, int] = collections.Counter()
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self.unknown_value = object()
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self.skip_constructors: bool = skip_constructors
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# overwrite this to deallocate env values if their only remaining use
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# is the output
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self.user_to_last_uses = self.node_to_last_non_output_use()
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self.lifted_constant_names = lifted_constant_names
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self.deferred_value = object()
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self.skip_folding_node_fn = skip_folding_node_fn
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def _support_dynamic_shape(self) -> bool:
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# ConstantFolder not support dynamic shape now
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return False
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def _deduce_value(self, node: torch.fx.Node) -> Any:
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if self.lifted_constant_names is None:
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return super().run_node(node)
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# if lifted_constant_names is passed in, no concrete value is available
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# so we just check if all inputs have values
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if self.skip_folding_node_fn is not None and self.skip_folding_node_fn(node):
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return self.unknown_value
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flattened_node_inps = pytree.arg_tree_leaves(*node.args, **node.kwargs)
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for inp in flattened_node_inps:
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if (
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isinstance(inp, torch.fx.Node)
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and inp.name not in (self.lifted_constant_names or ())
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and self.env[inp] != self.deferred_value
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):
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return self.unknown_value
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return self.deferred_value
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def is_impure(self, node: torch.fx.node.Node) -> bool:
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def is_woq_int8_pattern(node: torch.fx.node.Node) -> bool:
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return (
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node.target == torch.ops.prims.convert_element_type.default # type: ignore[return-value]
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and isinstance(node.args[0], torch.fx.Node)
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and "val" in node.args[0].meta
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and node.args[0].meta["val"].dtype == torch.int8 # type: ignore[union-attr]
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and node.args[1] == torch.bfloat16
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)
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if (
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is_woq_int8_pattern(node)
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or (
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node.target == torch.ops.aten.permute.default
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and len(node.users) == 1
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and is_woq_int8_pattern(next(iter(node.users)))
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)
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) and is_const_source(
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node.args[0], # type: ignore[arg-type]
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self.lifted_constant_names,
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):
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# Case 1: int8_weight -> dq -> bf16_weight
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# Case 2: int8_weight -> permute -> dq -> bf16_weight
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return True
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quant_registered = (
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getattr(torch.ops.quantized_decomposed, "dequantize_per_channel", None)
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is not None
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)
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if quant_registered and node.target in [
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torch.ops.quantized_decomposed.dequantize_per_channel.default,
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torch.ops.quantized_decomposed.dequantize_per_tensor.default,
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torch.ops.quantized_decomposed.dequantize_per_tensor.tensor,
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torch.ops.quantized_decomposed.convert_element_type.no_fuse,
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]:
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# For the pattern fp32_weight -> q -> dq
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# We only folding fp32_weight -> q
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# int8_weight and leave dq in graph to be fused
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return True
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return False
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def node_to_last_non_output_use(self) -> dict[torch.fx.Node, list[torch.fx.Node]]:
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last_non_output_use = collections.defaultdict(list)
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seen_uses = OrderedSet[torch.fx.Node]()
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output_node = next(iter(reversed(self.module.graph.nodes))) # type: ignore[arg-type, union-attr]
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for node in reversed(self.module.graph.nodes): # type: ignore[arg-type, union-attr]
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if node.target == "output":
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continue
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def add_use(inp: torch.fx.Node) -> None:
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if inp in seen_uses:
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return
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seen_uses.add(inp)
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last_non_output_use[node].append(inp)
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# In-place is fine since we don't mutate
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pytree.tree_map_only_(torch.fx.Node, add_use, (node.args, node.kwargs))
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# if this node is only used in output, we want to gc it right away
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if len(node.users) == 1 and output_node in node.users:
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last_non_output_use[node].append(node)
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return last_non_output_use
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def run_node(self, node: torch.fx.Node) -> Any:
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if node.target == "output":
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# because we remove nodes from env on last non output use,
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# re-define them now or we'll get error in interpreter
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def set_env(arg: torch.fx.Node) -> None:
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self.env[arg] = self.unknown_value
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# In-place is fine since we don't mutate
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pytree.tree_map_only_(torch.fx.Node, set_env, node.args)
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return super().run_node(node)
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args, kwargs = self.fetch_args_kwargs_from_env(node)
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flattened_inputs = pytree.arg_tree_leaves(*args, **kwargs)
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# We need to do this weird thing because in cases where flattened_inputs
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# contains a ScriptObject, equality checking results in a type error if
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# the types are different.
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if any(
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type(self.unknown_value) == type(input_) and self.unknown_value == input_
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for input_ in flattened_inputs
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):
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return self.unknown_value
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# TODO - fix errors with this
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if (
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node.op == "call_function"
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and node.target == aten._efficientzerotensor.default
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):
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return self.unknown_value
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# TODO - constant folding triton kernel returns the inputs -- fix this
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if (
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node.op == "call_function"
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and node.name == "triton_kernel_wrapper_functional_proxy"
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):
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return self.unknown_value
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# skip constructors, since inductor generates optimal code for them already
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# and turning into tensor would result in an additional global memory read
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# TODO - more complicated strategy
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if (
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self.skip_constructors
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and not is_const_source(node, self.lifted_constant_names)
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and not any(isinstance(e, torch.Tensor) for e in flattened_inputs)
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):
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return self.unknown_value
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# All mutations should either be removed or on inputs which we did not make constant
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if (
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isinstance(node.target, torch._ops.OpOverload)
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and torch.Tag.nondeterministic_seeded in node.target.tags
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):
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return self.unknown_value
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if node.op == "call_function" and isinstance(
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node.target, torch._ops.HigherOrderOperator
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):
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return self.unknown_value
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out = self._deduce_value(node)
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if isinstance(out, torch._C.ScriptObject):
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return out
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if out == self.unknown_value:
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return self.unknown_value
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if not is_const_source(node, self.lifted_constant_names) and (
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isinstance(out, torch.Tensor) or out == self.deferred_value
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):
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if out != self.deferred_value and out.device.type == "meta":
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return out
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if not self.insertable_tensor_check(out):
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return out
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if self.is_impure(node):
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return self.unknown_value
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self.add_node_replacement(node, out)
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flattened_node_inps = pytree.arg_tree_leaves(*node.args, **node.kwargs)
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for n in flattened_node_inps:
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if not isinstance(n, torch.fx.Node):
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continue
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self.replaced_uses[n] += 1
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for to_delete in self.user_to_last_uses.get(node, []):
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if self.replaced_uses[to_delete] == len(to_delete.users):
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self.node_replacements.pop(to_delete, None)
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return out
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def insertable_tensor_check(self, tensor: torch.Tensor) -> bool:
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return True
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def add_node_replacement(self, node: torch.fx.Node, tensor: torch.Tensor) -> None:
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self.node_replacements[node] = tensor
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def run(self) -> Any: # type: ignore[override]
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env: dict[torch.fx.Node, Any] = {}
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self.insert_placerholder_values(env)
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return super().run(initial_env=env)
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def insert_placerholder_values(self, env: dict[torch.fx.Node, Any]) -> None:
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for n in self.module.graph.find_nodes(op="placeholder"): # type: ignore[operator, union-attr]
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env[n] = self.unknown_value # type: ignore[assignment]
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if self.lifted_constant_names is None:
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return
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for n in self.module.graph.nodes: # type: ignore[union-attr]
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if n.name in (self.lifted_constant_names or ()):
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env[n] = self.deferred_value
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def constant_fold(
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gm: torch.fx.GraphModule,
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constraint_fn: Optional[Callable[[torch.fx.Node], bool]] = None,
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) -> None:
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with torch.utils._python_dispatch._disable_current_modes():
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cf = ConstantFolder(gm, skip_constructors=True)
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cf.run()
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for node, constant in cf.node_replacements.items():
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if constraint_fn is not None and not constraint_fn(node):
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continue
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replace_node_with_constant(gm, node, constant)
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erased_params = []
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for node in gm.graph.find_nodes(op="get_attr"):
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if len(node.users) == 0:
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if hasattr(gm, node.target):
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delattr(gm, node.target)
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erased_params.append(node)
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for node in erased_params:
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gm.graph.erase_node(node)
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gm.graph.eliminate_dead_code()
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gm.graph.lint()
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gm.recompile()
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def constant_graph_tag(
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gm: torch.fx.GraphModule,
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skip_constructors: bool = True,
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lifted_constant_names: Optional[list[str]] = None,
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skip_folding_node_fn: Optional[Callable[[torch.fx.Node], bool]] = None,
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) -> None:
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with torch.utils._python_dispatch._disable_current_modes():
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cf = ConstantFolder(
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gm,
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skip_constructors=skip_constructors,
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lifted_constant_names=lifted_constant_names,
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skip_folding_node_fn=skip_folding_node_fn,
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)
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cf.run()
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for node in gm.graph.nodes:
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if skip_folding_node_fn is not None and skip_folding_node_fn(node):
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node.meta[META_TAG] = MODULE_TAG
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continue
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if (
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is_const_source(node, lifted_constant_names)
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or node in cf.node_replacements
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or node in cf.replaced_uses
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):
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node.meta[META_TAG] = CONST_MODULE_TAG
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else:
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node.meta[META_TAG] = MODULE_TAG
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def run_and_get_constant_graph(
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gm: torch.fx.GraphModule,
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skip_constructors: bool = True,
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lifted_constant_names: Optional[list[str]] = None,
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skip_folding_node_fn: Optional[Callable[[torch.fx.Node], bool]] = None,
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) -> torch.fx.GraphModule:
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"""
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Construct a GraphModule which corresponds to the part which could be
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constant folded in provided gm.
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"""
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constant_graph_tag(
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gm, skip_constructors, lifted_constant_names, skip_folding_node_fn
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)
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def untag(node: torch.fx.Node) -> bool:
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used_to_fold = False
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for u in node.users:
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if u.meta[META_TAG] == CONST_MODULE_TAG:
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used_to_fold = True
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break
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if not used_to_fold:
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node.meta[META_TAG] = MODULE_TAG
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return used_to_fold
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# We rewrite the tags, if it's a constant being directly consumed, without
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# any folding opportunity, we keep it in main gm.
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for node in gm.graph.nodes:
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if node.op == "getattr" or (node.name in (lifted_constant_names or ())):
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untag(node)
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new_graph = torch.fx.Graph()
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node_remapping: dict[torch.fx.Node, torch.fx.Node] = {}
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output_nodes = []
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for node in gm.graph.nodes:
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if node.meta[META_TAG] == MODULE_TAG:
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continue
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new_node = new_graph.node_copy(node, lambda x: node_remapping[x])
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node_remapping[node] = new_node
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for user in node.users:
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if user.meta[META_TAG] == MODULE_TAG:
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output_nodes.append(new_node)
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break
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new_graph.output(tuple(output_nodes))
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new_graph.lint()
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new_gm = torch.fx.GraphModule(gm, new_graph)
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return new_gm
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