Files
pytorch/torch/_decomp/__init__.py
Edward Z. Yang de8d81275a Do not decompose in functionalization/proxy tensor if autograd wouldn't have decomposed (#164939)
This fixes AOTAutograd rms_norm not being bitwise equivalent to
eager, because it avoids a decomposition.  You can force the
decomposition by having the decomposition in the dispatch table,
but if eager mode wouldn't have decomposed (because it went to the fused
one), we now default to preserving the fused call by default.

This largely reverts https://github.com/pytorch/pytorch/pull/103275/ for view ops. This means that in inference mode we could hit the wrong C++ kernel; if this occurs we should just SymInt'ify the C++ kernel.

Another neat side effect of this change is that Inductor's generated kernels for rms_norm now have rms_norm in their name.

Signed-off-by: Edward Z. Yang <ezyang@meta.com>

Pull Request resolved: https://github.com/pytorch/pytorch/pull/164939
Approved by: https://github.com/bdhirsh
2025-10-11 01:03:55 +00:00

550 lines
19 KiB
Python

# mypy: allow-untyped-defs
import inspect
from collections import defaultdict
from collections.abc import Callable, Sequence
from functools import lru_cache, partial, wraps
from itertools import chain
from typing import Optional, TYPE_CHECKING, TypeVar, Union
from typing_extensions import ParamSpec
if TYPE_CHECKING:
from torch.export.decomp_utils import CustomDecompTable
import torch
import torch.library
from torch._ops import HigherOrderOperator, OperatorBase, OpOverload, OpOverloadPacket
from torch._prims_common import CustomOutParamAnnotation
from torch._subclasses.functional_tensor import FunctionalTensor
from torch.utils import _pytree as pytree
__all__ = [
"decomposition_table",
"pre_autograd_decomposition_table",
"meta_table",
"register_decomposition",
"get_decompositions",
"core_aten_decompositions",
"_should_decompose_because_unsafe_op",
]
_T = TypeVar("_T")
_P = ParamSpec("_P")
# TODO: relax key type here; torch registrations should be possible to; but
# right now this type is accurate
global_decomposition_table: dict[str, dict[torch._ops.OperatorBase, Callable]] = (
defaultdict(dict)
)
decomposition_table = global_decomposition_table["post_autograd"]
pre_autograd_decomposition_table = global_decomposition_table["pre_autograd"]
meta_table = global_decomposition_table["meta"]
def _should_decompose_because_unsafe_op(op: torch._ops.OperatorBase) -> bool:
"""
Returns True if the op must always decompose in export/compile tracing system
In export, we always decompose certain CIA ops that are tagged with
maybe_aliasing_or_mutating because we statically need to know if the op is
mutating or not. But these CIA ops could have different behaviour in runtime.
native_batch_norm is a prim op which has a wrong schema and it needs to be replaced
with correct schema. But until then, we will force decompose it via this tag.
"""
if not isinstance(op, torch._ops.OpOverload):
return False
if torch.Tag.maybe_aliasing_or_mutating in op.tags:
return True
return op == torch.ops.aten.native_batch_norm.default
def _add_op_to_registry(registry, op, fn):
"""
This is an internal API for adding an op to the decomposition table.
If op is OpOverload, it will be added to the registry directly.
If op is OpOverloadPacket, all the valid op_overloads in the packet will be added to the registry.
"""
overloads: list[Union[torch._ops.OperatorBase]] = []
if isinstance(op, HigherOrderOperator):
# There's no concept of overloads for HigherOrderOperator
registry[op] = fn
return
elif isinstance(op, OpOverload):
overloads.append(op)
else:
assert isinstance(op, OpOverloadPacket)
for ol in op.overloads():
overloads.append(getattr(op, ol))
for op_overload in overloads:
if op_overload in registry:
raise RuntimeError(f"duplicate registrations for {op_overload}")
# TorchScript dumps a bunch of extra nonsense overloads
# which don't have corresponding dispatcher entries, we need
# to filter those out, e.g aten.add.float_int
if torch._C._dispatch_has_kernel(op_overload.name()):
registry[op_overload] = fn
def _convert_out_params(f):
out_annotation = f.__annotations__.get("out")
# If there are no out params, do not wrap the function.
if not out_annotation:
return f
# Hack to detect when out is a Tuple. There seems to be no pretty way of doing this
if getattr(out_annotation, "__origin__", None) is tuple:
sig = inspect.signature(f)
out_names = sig.return_annotation._fields
# If out is a tuple, we need to register a function that unpacks all the out
# elements as this is what native_functions.yaml expects
@wraps(f)
def _fn(*args, **kwargs):
out_kwargs = tuple(kwargs.pop(o, None) for o in out_names)
# Either all of the out kwargs are set or none of them
is_none = out_kwargs[0] is None
assert all((o is None) == is_none for o in out_kwargs)
return f(*args, **kwargs, out=None if is_none else out_kwargs)
out_params = [
inspect.Parameter(
o,
kind=inspect.Parameter.KEYWORD_ONLY,
default=None,
annotation=t,
)
for o, t in zip(out_names, out_annotation.__args__)
]
# Drop the out parameter and concatenate the new kwargs in the signature
params = chain((v for k, v in sig.parameters.items() if k != "out"), out_params)
_fn.__signature__ = inspect.Signature( # type: ignore[attr-defined]
parameters=params, # type: ignore[arg-type]
return_annotation=sig.return_annotation,
)
# Drop the out parameter and concatenate the new kwargs in the annotations
_fn.__annotations__ = {k: v for k, v in f.__annotations__.items() if k != "out"}
for o in out_params:
_fn.__annotations__[o.name] = o.annotation
# Propagate that this function is wrapped by `out_wrapper`
_fn._torch_decompositions_out_wrapper = f._torch_decompositions_out_wrapper # type: ignore[attr-defined]
return _fn
# Alternatively, there may be a single tensor out parameter with a name
# other than "out". This will need special treatment and is indicated by an
# annotation, which we will remove here so it is not exposed after wrapping.
custom_out_param_name = f.__annotations__.pop(CustomOutParamAnnotation, None)
if custom_out_param_name:
@wraps(f)
def _fn(*args, **kwargs):
out_kwarg = kwargs.pop(custom_out_param_name, None)
return f(*args, **kwargs, out=out_kwarg)
out_param = inspect.Parameter(
custom_out_param_name,
kind=inspect.Parameter.KEYWORD_ONLY,
default=None,
annotation=out_annotation,
)
# Drop the out parameter and concatenate the new kwarg in the signature
sig = inspect.signature(f)
params = chain(
(v for k, v in sig.parameters.items() if k != "out"), (out_param,)
)
_fn.__signature__ = inspect.Signature( # type: ignore[attr-defined]
parameters=params, # type: ignore[arg-type]
return_annotation=sig.return_annotation,
)
# Drop the out parameter and concatenate the new kwargs in the annotations
_fn.__annotations__ = {k: v for k, v in f.__annotations__.items() if k != "out"}
_fn.__annotations__[out_param.name] = out_param.annotation
return _fn
return f
def register_decomposition(
aten_op, registry=None, *, type="post_autograd", unsafe=False
) -> Callable[[Callable[_P, _T]], Callable[_P, _T]]:
"""
A decorator to register a function as a decomposition to the Python
decomposition table. Use it like this::
@register_decomposition(torch.ops.aten.clamp_min)
def clamp_min(x):
return torch.clamp(self, min=min)
If you are writing a new decomposition, consider contributing it
directly to PyTorch in torch._decomp.decompositions.
This API is experimental; we are almost certainly going to extend
the API when we make decompositions eligible for use in transforms (e.g.,
autograd) and not just backend tracing, where we then need to know if a
decomposition can be used to simulate a transform.
By default, we also will register it to the Meta key of dispatcher,
and replace the c++ Meta implementation if there is already one.
unsafe kwarg is for reuse of this function for registering non-function
things
"""
assert type in {"post_autograd", "pre_autograd", "meta"}
def decomposition_decorator(fn: Callable[_P, _T]) -> Callable[_P, _T]:
orig_fn = fn
if not unsafe:
fn = _convert_out_params(fn)
nonlocal registry
if registry is None:
registry = global_decomposition_table[type]
def register(op):
_add_op_to_registry(registry, op, fn)
# To handle allowing multiple aten_ops at once
pytree.tree_map_(register, aten_op)
return orig_fn
return decomposition_decorator
def get_decompositions(
aten_ops: Sequence[Union[torch._ops.OperatorBase, OpOverloadPacket]],
type: str = "post_autograd",
) -> dict[torch._ops.OperatorBase, Callable]:
"""
Retrieve a dictionary of decompositions corresponding to the list of
operator overloads and overload packets passed as input. Overload
packets will include all decomposed overloads in the packet. If there is
no decomposition for a requested operator, it is silently ignored.
This API is experimental; we are almost certainly going to give an alternate,
more recommended formulation, where a user provides the set of operators
they know how to implement, and we provide decompositions for everything
not in this set.
"""
assert type in {"post_autograd", "pre_autograd", "meta"}
registry = global_decomposition_table[type]
packets_to_overloads = defaultdict(list)
for opo in registry:
if isinstance(opo, (OpOverload, OpOverloadPacket)):
packets_to_overloads[opo.overloadpacket].append(opo)
decompositions: dict[torch._ops.OperatorBase, Callable] = {}
for op in aten_ops:
if isinstance(op, OpOverloadPacket) and op in packets_to_overloads:
for op_overload in packets_to_overloads[op]:
decompositions[op_overload] = registry[op_overload]
elif isinstance(op, (torch._ops.OperatorBase)) and op in registry:
decompositions[op] = registry[op]
return decompositions
def remove_decompositions(
decompositions: dict[torch._ops.OperatorBase, Callable],
aten_ops: Sequence[Union[OpOverload, OpOverloadPacket]],
) -> None:
"""
Given a dictionary of decompositions obtained from get_decompositions(), removes
operators associated with a list of operator overloads and overload packets passed
as input. If the decomposition dictionary does not contain a decomposition that is
specified to be removed, it is silently ignored.
"""
for op in aten_ops:
if isinstance(op, OpOverloadPacket):
for overload_name in op.overloads():
opo = getattr(op, overload_name)
decompositions.pop(opo, None)
elif isinstance(op, OpOverload):
decompositions.pop(op, None)
# populate the table
import torch._decomp.decompositions
import torch._refs
def core_aten_decompositions() -> "CustomDecompTable":
from torch.export.exported_program import default_decompositions
return default_decompositions()
# See NOTE [Core ATen Ops]
#
# list was copied from torch/_inductor/decomposition.py
# excluding decompositions that results in prim ops
# Resulting opset of decomposition is core aten ops
def _core_aten_decompositions_post_autograd() -> dict[
torch._ops.OperatorBase, Callable
]:
aten = torch.ops.aten
return get_decompositions(
[
aten.addcdiv,
aten.addcdiv_,
aten.addcmul,
aten.addcmul_,
aten.addr,
aten.affine_grid_generator,
aten.alias_copy,
aten.all,
aten.aminmax,
aten.arange.default,
aten.arange.start,
aten.avg_pool2d_backward,
aten.baddbmm,
aten.binary_cross_entropy,
aten.binary_cross_entropy_backward,
aten.binary_cross_entropy_with_logits,
aten.block_diag,
aten.bernoulli.p,
aten.bernoulli.default,
aten.celu,
aten.celu_,
aten.channel_shuffle,
aten.clamp_max,
aten.clamp_min,
aten.col2im,
aten.count_nonzero,
aten.linalg_cross,
aten.cudnn_batch_norm,
aten.cudnn_batch_norm_backward,
aten.miopen_batch_norm_backward,
aten.deg2rad,
aten.deg2rad_,
aten.detach,
aten.diag_embed,
aten.diagonal_backward,
aten.diagonal_copy,
aten.dot,
aten.vdot,
aten.elu_,
aten.elu_backward,
aten._embedding_bag,
aten.embedding_dense_backward,
aten.empty_like,
aten._euclidean_dist.default,
aten.expand_as,
aten.expand_copy,
aten.eye,
aten.fill,
aten.fill_,
aten.floor_divide,
aten.frac,
aten.frac_,
aten._fused_moving_avg_obs_fq_helper,
aten.gelu_,
aten.gelu_backward,
aten.glu,
aten.glu_backward,
aten.hardshrink,
aten.hardsigmoid,
aten.hardsigmoid_,
aten.hardsigmoid_backward,
aten.hardswish,
aten.hardswish_,
aten.hardswish_backward,
aten.hardtanh_,
aten.hardtanh_backward,
aten.heaviside,
aten.heaviside_,
aten.huber_loss,
aten.huber_loss_backward,
aten.im2col,
aten.index_add.out,
aten.index_add.default,
aten.index_add_,
aten.index_copy.out,
aten.index_copy.default,
aten.index_copy_,
aten.index_fill.int_Scalar,
aten.index_fill.int_Tensor,
aten.index_fill.int_Scalar_out,
aten.index_fill.int_Tensor_out,
aten.index_fill_,
aten.isin,
aten.isneginf,
aten.isposinf,
aten.l1_loss,
aten._lazy_clone,
aten._test_parallel_materialize,
aten.leaky_relu_,
aten.leaky_relu_backward,
aten.lerp,
aten.lerp_,
aten.linspace,
aten.logaddexp,
aten.logaddexp2,
aten.logit,
aten.logit_,
aten.logit_backward,
aten.log_sigmoid_backward,
aten.log_sigmoid_forward,
aten._log_softmax_backward_data,
aten.logspace,
aten.logsumexp.default,
aten.masked_fill,
aten.masked_fill_,
aten.max_unpool2d,
aten.max_unpool3d,
aten.mish,
aten.mish_,
aten.mish_backward,
aten.mse_loss,
aten.mse_loss_backward,
aten.multi_margin_loss,
aten.multilabel_margin_loss_forward,
aten.mv,
aten.mvlgamma,
aten.mvlgamma_,
aten.nansum,
aten.nan_to_num,
aten.nan_to_num_,
aten.narrow,
aten.native_batch_norm_backward,
aten.native_dropout_backward,
aten.native_group_norm_backward,
aten.native_layer_norm_backward,
aten._fused_rms_norm,
aten._fused_rms_norm_backward,
aten.new_empty,
aten.new_full,
aten.new_ones,
aten.new_zeros,
aten.nll_loss2d_forward,
aten.nll_loss2d_backward,
aten.nll_loss_backward,
aten.nll_loss_forward,
aten.norm.ScalarOpt_dtype,
aten.norm.Scalar,
aten.norm.ScalarOpt_dim_dtype,
aten.norm.ScalarOpt_dim,
aten.norm.dtype_out,
aten.norm.out,
aten.norm.names_dtype_out,
aten.norm.names_out,
aten.norm.ScalarOpt_dtype_out,
aten.norm.Scalar_out,
aten.ones,
aten.ones_like,
aten.pixel_shuffle,
aten.pixel_unshuffle,
aten._prelu_kernel,
aten._prelu_kernel_backward,
aten._reshape_alias,
aten.rad2deg,
aten.rad2deg_,
aten.reflection_pad1d,
aten.reflection_pad1d_backward,
aten.reflection_pad2d,
aten.reflection_pad2d_backward,
aten.reflection_pad3d,
aten.reflection_pad3d_backward,
aten.replication_pad1d,
aten.replication_pad2d,
aten.replication_pad3d,
aten.renorm,
aten.renorm_,
aten.replication_pad2d,
aten.resize_as,
aten.roll,
aten.rot90,
aten.rrelu_with_noise,
aten.rrelu_with_noise_,
aten.rsub,
aten._safe_softmax,
aten._scaled_dot_product_flash_attention_for_cpu.default,
aten.select_backward,
aten.select_scatter,
aten.sgn,
aten.sgn_,
aten.sigmoid_backward,
aten.silu,
aten.silu_,
aten.silu_backward.grad_input,
aten.silu_backward,
aten.sinc,
aten.sinc_,
aten.slice_backward,
aten.smooth_l1_loss,
aten.smooth_l1_loss_backward,
aten.soft_margin_loss,
aten.soft_margin_loss_backward,
aten._softmax_backward_data,
aten.softplus,
aten.softplus_backward,
aten.softshrink,
aten.special_entr,
aten.special_log_ndtr,
aten.special_xlog1py,
aten.split.Tensor,
aten.split_with_sizes_copy,
aten.squeeze_copy,
aten.squeeze.default,
aten.squeeze.dim,
aten.std.correction,
aten.std.out,
aten.std.correction_out,
aten.std.names_out,
aten.std.correction_names_out,
aten.std_mean.correction,
aten.std_mean.correction_out,
aten.stack,
aten.sum.default,
aten.sum.out,
aten.t,
aten.t_copy,
aten.take,
aten.tanh_backward,
aten.threshold,
aten.threshold_,
aten.threshold_backward,
aten.trace,
aten.transpose.int,
aten.transpose_copy,
aten.tril,
aten.tril_,
aten.triu,
aten.triu_,
aten.unbind,
aten.unfold_backward,
aten.unfold_copy,
aten._unsafe_index,
aten._unsafe_index_put,
aten._unsafe_masked_index,
aten._unsafe_masked_index_put_accumulate,
aten.unsafe_split.Tensor,
aten.unsafe_split_with_sizes,
aten.unsqueeze_copy,
aten._unsafe_view,
aten.upsample_linear1d,
aten.upsample_bilinear2d.out,
aten.upsample_trilinear3d.out,
aten.upsample_nearest2d_backward,
aten.view_as_complex,
aten.xlogy,
aten.xlogy_,
aten.zero,
aten.zero_,
aten.zeros,
aten.zeros_like,
aten._chunk_cat,
aten._weight_norm_interface,
]
)