Commit Graph

70 Commits (1bccb4fc8aa221cfb1146bcf778b75a95c52b39f)

Author SHA1 Message Date
Anup Gangwar 5d7a6c2976
[tosa] Support for Aten[Unsqueeze|Contiguous|Dropout|Reshape|View] ops (#700) 2022-03-25 14:15:07 -07:00
Gaurav Shukla 7c3ba25238 [LINALG] Add decomposition of `aten.dropout` op
- This commit adds decomposition of `aten.dropout` op. It also covers the
  training mode of the same op.
- It also adds lowering of `aten.sub.float` op.

Signed-Off-by: Gaurav Shukla <gaurav@nod-labs.com>
2022-03-22 13:14:49 +05:30
Vigilans 63fb1e5aad Bump LLVM at 8361c5da30588d3d4a48eae648f53be1feb5cfad 2022-03-18 13:16:14 -04:00
Sean Silva 84a9693006 Elide `!torch.` prefix in nested dialect types.
This leads to much more succinct types in many cases:

```
!torch.list<!torch.int>
!torch.list<int>

!torch.tuple<!torch.list<!torch.int>, !torch.list<!torch.int>>
!torch.tuple<list<int>, list<int>>

!torch.optional<!torch.list<!torch.int>>
!torch.optional<list<int>>

!torch.list<list<list<tensor>>>
!torch.list<!torch.list<!torch.list<!torch.tensor>>>
```

I would like to take this further and allow omitting the `!torch.`
prefix in all cases, but that's harder -- for example, we currently use
`FuncOp` for functions, and so I don't think we can customize the
printing there. It seems like it will be a longer road to getting that
level of customization.
2022-03-15 17:24:08 -07:00
Ramiro Leal-Cavazos 5ec70c175d
[LINALG] Add torch-to-linalg lowering for `TensorStaticInfoCastOp` (#634)
This commit adds a lowering for `TensorStaicInfoCastOp` that simply
replaces the op with the `tensor::CastOp`.
2022-03-02 13:35:26 -08:00
Anup Gangwar c60468f141
[tosa] Support for Aten[Zeros|Ones|Fill_Scalar] ops (#604)
Signed-off-by: Anup Gangwar <anup.gangwar@arm.com>

Co-authored-by: Anup Gangwar <anup.gangwar@arm.com>
2022-02-16 09:53:51 -08:00
Gaurav Shukla 78c7844c6c [LINALG] Add E2E support for `aten.eq.int` op
- This commit adds lowering of `aten.eq.int` op as a part of
  `convert-torch-to-std` pass.
- It also refactors the code for binary comparison ops lowering.

Signed-Off-by: Gaurav Shukla <gaurav@nod-labs.com>
2022-02-15 01:37:35 +05:30
Gaurav Shukla f00d1686c8 [LINALG] Add E2E support for `aten.[Bool.Tensor|Float.Tensor]` op
- This commit adds lowering of `aten.Bool.Tensor` and
  `aten.Float.Tensor` op as a part of `convert-torch-to-linalg` pass.
- It also adds support for returning bool types.
- It also fixes lowering of the `aten.Int.Tensor` op for non-zero rank
  input tensors.
- If a scalar number is converted to a 0-d tensor and passed on to the
  `aten.Float.Tensor` op, it folds to the scalar number.

Signed-Off-by: Gaurav Shukla <gaurav@nod-labs.com>
2022-02-14 23:09:20 +05:30
Anup Gangwar 756b75fb2d
[tosa] Support for some ops and fix for Issue #532 (#575)
* [tosa] Support for AtenNe[Tensor|Scalar]Op, AtenLog2Op,
AtenBitwiseAndTensorOp, AtenSquareOp and AtenThresholdOp
* Fix for Issue #532 - Mixed input types for few ops and updated few
tests to use i32 instead of i64

Signed-off-by: Anup Gangwar <anup.gangwar@arm.com>

Co-authored-by: Anup Gangwar <anup.gangwar@arm.com>
2022-02-11 12:30:02 -08:00
Gaurav Shukla bd177bdfc7 [TORCH][MLIR] Add run-time assert support in Torch-dialect
- This commit adds `aten.assert` op in the Torch dialect.
- The `aten.assert` op is lowered to `mlir::Assert` op.

Signed-Off-by: Gaurav Shukla <gaurav@nod-labs.com>
2022-02-09 12:03:01 -05:00
Anup Gangwar f9f97ea184 * [tosa] Support for AtenNativeLayerNormOp
* [tosa] Support for AtenPermuteOp

Signed-off-by: Anup Gangwar <anup.gangwar@arm.com>
2022-02-04 14:46:31 -05:00
Anup Gangwar 454fa9d123
* [tosa] Support for AtenFlattenUsingIntsOp (#548) 2022-01-28 21:38:56 -08:00
Anup Gangwar 7a5736facd
* [tosa] Support for AtenReshapeOp (#543)
* [tosa] Support for AtenBatchNormOp

Signed-off-by: Anup Gangwar <anup.gangwar@arm.com>

Co-authored-by: Anup Gangwar <anup.gangwar@arm.com>
2022-01-27 14:38:59 -08:00
stephenneuendorffer 3fd9b7789e
Bump LLVM to 881ff4e4ebe8cc0cc045c7c167cffb01f94f27f8 (#539) 2022-01-25 22:16:30 -08:00
Anup Gangwar f8080bd1c5
* [tosa] Support for AtenRsubScalarOp for scalar constants (#531)
* [tosa] Support for AtenCeilOp and AtenReciprocalOp
* [tosa] Support for comparator ops, Aten[Gt|Lt|Eq][Tensor|Scalar]Op with scalar constant
* [tosa] Support for Scalar variants of Aten[Mul|Div|Add|Sub] Ops with scalar constants

Signed-off-by: Anup Gangwar <anup.gangwar@arm.com>

Co-authored-by: Anup Gangwar <anup.gangwar@arm.com>
2022-01-20 10:58:30 -08:00
dan 3745f54489 Update external/llvm-project
- Add `qualified` to ods because of
https://reviews.llvm.org/D113873 and https://reviews.llvm.org/D116905
- Needed to revert https://github.com/llvm/torch-mlir/pull/520 as it
was based on an old torch version.
https://github.com/llvm/torch-mlir/pull/527 will bring this back with
a better design.
- Change ConvertAtenCatOp to use more accurate tensor shape info and
as much static info as possible to pass `tensor.insert_slice`
verification code added by https://reviews.llvm.org/D114715
- Other minor fixes
2022-01-18 13:25:42 -05:00
Anup Gangwar d69d29b7a6 * [tosa] Support for AtenPowTensorScalarOp with constant Scalar as input
Signed-off-by: Anup Gangwar <anup.gangwar@arm.com>
2022-01-11 22:55:54 -05:00
xndcn 5eed562e19 add aten.sub.int/aten.mul.int lowering in TorchToStd 2021-12-17 10:35:15 -08:00
Anup Gangwar a6c3050dd0 * [tosa] Support for Maximum and Minimum
Signed-off-by: Anup Gangwar <anup.gangwar@arm.com>
2021-12-15 11:58:19 -08:00
Anup Gangwar cce490d71d
* [tosa] Support for Rsqrt legalization (#480)
Signed-off-by: Anup Gangwar <anup.gangwar@arm.com>

Co-authored-by: Anup Gangwar <anup.gangwar@arm.com>
2021-12-14 10:03:58 -08:00
Suraj Sudhir c9c9b68d1f [tosa] Add Torch reduction operators
- Supports variants with multiple dims, one dim, all dime
- Leverages legalize_common and legalize_utils code from
TensorFlow-TOSA work

Signed-off-by: Suraj Sudhir <suraj.sudhir@arm.com>
2021-12-03 09:01:48 -08:00
dan 03fdf56f21 add aten.add.int lowering in TorchToStd 2021-11-29 13:22:50 -05:00
Suraj Sudhir 628a21bb13
[mlir][tosa] Refactor conversions to use templates (#416)
- Remove use of conversion construction macros
- Add mul and div op conversions
- Add corresponding tests

Signed-off-by: Suraj Sudhir <suraj.sudhir@arm.com>
2021-11-11 16:15:58 -08:00
Suraj Sudhir 1019ddf5a0 [tosa] Add structure for eltwise ops
Add a bunch of op legalizations.

Signed-off-by: Suraj Sudhir <suraj.sudhir@arm.com>
2021-11-11 11:03:24 -08:00
George Petterson f41958037a Add NumToTensor 2021-11-08 15:56:52 -05:00
Prashant Kumar 53b4275ef5 Add lowering of `aten.Int.Tensor` op.
The lowering of `aten.Int.Tensor` op has been added.
The changes has been made as a part of `convert-torch-to-linalg` pass.

Signed-off-by: Prashant Kumar <prashant@nod-labs.com>
2021-11-01 21:58:08 +05:30
Sean Silva eb6996d557 Update llvm-project to 6f9c25167d16acff3ff8e4f54a8c14a2a175fc59
- Changes to dialect conversion that result in no-op materializations
  not being created.
2021-10-28 17:43:04 -07:00
Suraj Sudhir 7e4ef74774
[tosa] Add Torch.sigmoid fp32 to TOSA (#386)
* [tosa] Add Torch.sigmoid fp32 to TOSA

Signed-off-by: Suraj Sudhir <suraj.sudhir@arm.com>
2021-10-28 10:09:12 -07:00
Yi Zhang 0902438882 Update llvm-project to a54f4eae0e1d0ef5adccdcf9f6c2b518dc1101aa
This brings in https://reviews.llvm.org/D110797. PRs that are in
progress will need to use scripts provided by
https://llvm.discourse.group/t/psa-removed-arithmetic-ops-from-standard/4455.
2021-10-18 13:36:42 -04:00
Sean Silva 0c5c84d63d Add a basic TOSA E2E backend.
We lower through linalg-on-tensors and use RefBackend to run it.
This adds enough support for a "tanh" op. Adding more ops should be
fairly mechanical now that things are wired up. Run with:
```
./tools/torchscript_e2e_test.sh -c tosa
```

The backend structure is very similar to linalg-on-tensors based E2E
backends and is a nice parallel (see `tosa_backend.py`). Actually, this
forced a nice refactoring to the layering here. We removed
`torchscript-module-to-linalg-on-tensors-backend-pipeline` and instead
require separately running
```
torchscript-function-to-torch-backend-pipeline,torch-backend-to-linalg-on-tensors-backend-pipeline
```
This highlights the step that lowers to the "torch backend contract"
of cleaned up `torch` dialect ops is a critical step in the lowering.
Going forward, that is the key load-bearing contract of the torch-mlir
project, not the linalg-on-tensors backend contract.

Recommended review order:
- `TorchToTosa.cpp` / `TorchToTosa/basic.mlir`
- `python/torch_mlir_e2e_test/torchscript/configs/tosa_backend.py` and
  the new `utils.py` file there.
- `python/torch_mlir_e2e_test/tosa_backends/linalg_on_tensors.py` and
  `abc.py` in that directory for the TOSA backend e2e interface.
- other misc mechanical changes
2021-10-08 09:59:45 -07:00
Sean Silva 4fad753073 Move external/torch-mlir to the root of the repo. 2021-09-27 17:11:08 -07:00
Sean Silva a99cbeeb7e Move TorchConversion dialect and TorchTo* into torch-mlir 2021-09-23 21:39:31 -07:00
Sean Silva 1a0b953ea7 Eliminate almost all mentions of IREE.
A few remain in examples/docs that will be naturally be updated in due
time.

This regresses the list support and the general direction of more widely
supported control flow, lists/dicts/globals that we were going for with
the TorchScript path. The idea is that we are deferring that work to
make torch-mlir a very clean standalone thing. We will reboot it,
probably using some of the tools of iree_pydm to make it simpler, and in
a more natural place (such as an iree-torch repo that depends on IREE and
torch-mlir to build a working PyTorch frontend solution for IREE -- it
was really weird that npcomp depended on IREE).
2021-09-22 16:06:38 -07:00
Sean Silva f9c48d0b89 Bring up new RefBackend.
`tools/torchscript_e2e_test.sh` is all green.

This needs a few passes I put into torch-mlir/lib/RefBackend (not to be
confused with `npcomp/lib/RefBackend`, which will soon be deleted).

For the sake of review, since this brings together a lot of things, I
split this into its own commit. I temporarily commented out some "list"
stuff that we are going to remove as part of the torch-mlir refocus.
2021-09-22 14:20:22 -07:00
Sean Silva ed2afe43e7 Fix TorchToIREE lowering.
We needed to resize the list, not just reserve capacity.
2021-09-03 23:57:54 +00:00
Sean Silva 1dec561cfd Update llvm-project to 830c0b9023cd0cf91955900e0d96283e7a8c3711
- builder.getSymbolRefAttr is gone.
- OpAsmOpInterface's getAsmResultNames method needs explicit override
- a bunch of churn for builtin.func needing to be made explicit (and
  sometimes implicit?)
- operation printers no longer need to print the operation name
  themselves.
- snuck in beneficial trivial addition to TmpDeleteDeadIREEListsPass to
  test a particular upstream change e2e with my local patchset.
2021-09-03 14:16:38 -07:00
Sean Silva cab8d922ec Add TorchToIREE and factor out TorchConversion dialect.
This converts a basic list op (torch.prim.ListConstruct) to the IREE
dialect.

```
    def forward(self, x: float):
            return [x, x]
```

turns into:

```
builtin.func @forward(%arg0: !torch.float) -> !torch.list<!torch.float> {
  %0 = torch.prim.ListConstruct %arg0, %arg0 : (!torch.float, !torch.float) -> !torch.list<!torch.float>
  return %0 : !torch.list<!torch.float>
}
```

which turns into:

```
builtin.func @forward(%arg0: f64) -> !iree.list<f64> {
  %c1 = constant 1 : index
  %c0 = constant 0 : index
  %c2 = constant 2 : index
  %0 = iree.list.create %c2 : !iree.list<f64>
  iree.list.set %0[%c0], %arg0 : !iree.list<f64>, f64
  iree.list.set %0[%c1], %arg0 : !iree.list<f64>, f64
  return %0 : !iree.list<f64>
}
```

As part of doing this, I realized that it was time to formalize the IR
form that we reach right before running TorchTo{Linalg,Std,...}. We now
call it the "Torch backend contract". We then lower the "Torch backend
contract" to the "npcomp backend contract", which involves the new
TorchConversion (`torch_c`) dialect, which holds ops that need to
operate on both the npcomp backend types (e.g. builtin tensors, i1, IREE
list, etc.) and the `!torch` types.

This made more sense, as I realized that if I didn't factor out
`torch_c` then the Torch dialect would have a dependency on IREE
dialect (we previously didn't notice this was an issue because we only
depended on `builtin` types), which seemed wrong to me.

Recommended review order:
- TorchToIREE.cpp / `TorchToIREE/basic.mlir`
- Look at the new structure of createTorchScriptToNpcompBackendPipeline.
  It now lives in TorchConversion/Transforms/Passes.cpp and cleanly
  calls into `Torch::createTorchScriptToTorchBackendPipeline` for the
  frontend lowering to the Torch backend contract.
- Mechanical change extracting
  `torch_c.{to,from}_{i1,i64,f64,builtin_tensor,iree_list}` into a new
  TorchConversion dialect, and a few passes specific to the lowering
  from the Torch backend contract to the npcomp backend contract.
- Minor fixes to TorchToLinalg.cpp to use unconverted operands (now that
  we convert lists as part of operand materialization, we need to use
  the original operands). Also added test for AtenMaxPool2dOp and fixed
  m_TorchConstantIntList.
- TmpDeleteDeadIREELists pass. Temporary pass for deleting dead IREE lists that
  are created as part of operand materialization for conv/max pool/avg pool ops
  in TorchToLinalg.
2021-08-16 15:01:58 -07:00
Yi Zhang 0342b73bf1 Add torch.aten.flatten.using_ints and aten.MaxPool2d linalg lowering
- torch.aten.flatten.using_ints to linalg lowering
- torch.aten.max_pool2d to linalg lowering
- Support torch.aten.conv2d for more flexible dilation and strides values
2021-08-04 12:00:43 -04:00
Sean Silva f168cacd6d Remove TCF and TCP.
These were legacy concepts that are now superceded by direct Torch to
linalg-on-tensors lowering. These were based on some very early thinking
related to the layering of frontends vs codegen, which is now obsolete
because:
- We expected a lot more centralization at the frontend (TCF) level. It
  turns out that frontend needs really vary a lot, and there is no grand
  unifying TCF dialect plausible. The additional layer isn't worth it.
- Linalg-on-tensors obsoletes the primary need for TCP. There are still
  a few things not representable with linalg-on-tensors, but the support
  is growing and the whole "not included in linalg-on-tensors" direction
  needs to be rethought. Our TCP dialect didn't cover any of the
  actually important things in this space (such as sort, FFT, top-k,
  etc.).

See historical [slides](https://drive.google.com/file/d/1iljcpTQ5NPaMfGpoPDFml1XkYxjK_6A4/view) / [recording](https://drive.google.com/file/d/1jSPa8TwPKUt0WuLquGc8OgSUVYJHMvWZ/view)
for more details on the origin story here.

Their presence was confusing users too
[bug](https://github.com/llvm/mlir-npcomp/issues/248).

Also,
- Trim down npcomp-run-mlir testing. It was testing TCF to TCP
  lowering for the most part. The essential stuff is retained and
  rephrased with linalg-on-tensors. (we should probably rename it
  "refback-run" or something, as it is just a way to invoke RefBackend)
- test/Python/Backend/RefJIT/simple_invoke_numpy.py is XFAIL'ed. Our
  "anti-framework" direction seems to be the likely future path.
2021-08-02 12:08:39 -07:00
Stella Laurenzo 2ecbcbf8c7
Bump llvm-project to a085c23aa3c8f91866d7f4588d4f683407dc775d. (#250)
* Added additional *ToLLVM conversion patterns (they were disaggregated from standard).
* Misc renames.
* Spelling change on ConvNCHW op, and it now expects strides and dilations attributes.
2021-07-23 14:13:19 -07:00
Sean Silva 83b5b5456d Bump llvm-project to da289a174fc6617c7be37be2947480510fd4f02a
- Build adjustments for `.cpp.inc` dialect files.
- Renaming of `memref.dim` to `tensor.dim` for tensor case.

Minor changes:
- Renaming of `mlir::linalg::ReassociationIndices` to
  `mlir::ReassociationIndices`.
- Adjust command line option parsing in npcomp-run-mlir.
2021-07-07 13:57:29 -07:00
Sean Silva 79928cd2dd Generalize support for elementwise ops.
We plumb through e2e a fair number of interesting cases:
- unary, binary, ternary elementwise ops
- ops like `torch.aten.add.Tensor` that also take a scalar parameter
- static size-1 broadcasting

We allow the static size-1 broadcasting case, but emit a runtime error
in the case of dynamic size-1 broadcasting. This seems like a sweet spot
subset of things that can be lowered directly to linalg, while not being
overly constraining to users. This is consistent with what IREE is doing
for CHLO->Linalg lowering as well
([code](50bf7a87e4/iree/compiler/InputConversion/MHLO/BroadcastingToLinalgPatterns.cpp (L1))).

To test the static size-1 case, we added support for the
`torch.aten.unsqueeze` op and lowering for it through
`linalg.tensor_expand_shape`. This involved a generalization of
`MaximizeValueSemantics` able to handle it (the solution there also
works for `torch.aten.flatten.using_ints` which we need for ResNet
anyway)

Also, a few minor additional changes:
- Add `VerifyInvariantsBeforeBackendLowering` pass, which catches a
  large class of errors before we get to backend lowering (now that we
  are doing dialect conversion, the errors are way nicer if we just emit
  them up front rather than in the guts of a random pattern).
- Minor change to RefBackend to allow `linalg.tensor_expand_shape`.

Recommended review order:
- e2e tests in elementwise.py
- `ConvertElementwiseOp` in TorchToLinalg.cpp + elementwise.mlir test
- `ConvertAtenUnsqueezeOp` in TorchToLinalg.cpp + unsqueeze.mlir test
- RefineTypes.cpp + tests
- MaximizeValueSemantics changes + test
- VerifyInvariantsBeforeBackendLowering pass + test
2021-06-28 13:28:38 -07:00
Sean Silva 145d4ae23c Bump llvm-project to a37cf17834d39411ed1d669098b428f8374c5b45
Changes:
- Change to operand ordering of `linalg.fill`.
2021-06-23 10:03:29 -07:00
Yi Zhang 45f2edfc7a Add TorchToSCF pass.
1. Add TorchToSCF pass.
2. Convert prim.If and prim.If.yield.
2021-06-23 08:06:43 -07:00
Yi Zhang e6adecac83 Convert Torch constant ops to std.constant 2021-06-18 12:22:47 -07:00
Sean Silva 333e07a74e Add `torch.vtensor.literal` op.
This op is much better behaved than the `torch.tensor.literal` op
(which is the new name of the `torch.tensor` op). In particular
`torch.tensor.literal`:
- always has a maximally refined type.
- always has value semantics.
- can be constant folded / CSE'd.

ReduceOpVariants is changed to perform the transformation from
`torch.tensor.literal` to `torch.vtensor.literal` (which in general
involves static information casts and copies.

This new op also allowed tightening up `torch.tensor.literal` to only
accept NonValueTensorType (instead of any tensor type).

This new ".literal" name is more descriptive. It was getting too
confusing seeing an op called just `torch.tensor` (we originally called
it that because that's the name of the similar function in the Torch
Python API, but it just doesn't fit here).
2021-06-17 14:37:04 -07:00
Sean Silva f49ebf1690 Add `!torch.int` type.
This replaces the ad-hoc use of `i64` throughout the Torch layer, and
helps to keep it crystal clear the distinction between `!torch.int`
(which is modeling the Python `int` type) and the various types that
serve as dtypes of tensors, which are a totally different type universe.

Changes:
- `!torch.int` type and C bindings.
- Change `torch.constant.int` parser to not need the `: i64` at the end.
- `m_TorchConstantInt` matcher to aid with matching constants.
- BackendTypeConversion changes for `!torch.int` -> `i64` type
  conversion.
- Refactor finalizing patterns in FinalizingBackendTypeConversionPass
  (they were getting very repetitive).
- Mechanical rewriting of `!torch.int` to `i64` in all the tests, and
  `AnyTorchIntType` to `Torch_IntType` in the `.td` files.
2021-06-17 07:28:23 -07:00
Sean Silva 784156a998 Add `!torch.bool` type.
This finishes removing the dependence on the basicpy dialect!

Changes:
- Add `!torch.bool` type and replace use of `!basicpy.BoolType` in
  Torch-related code.
- Rename BuiltinTensorize to BackendTypeConversion since now it handles
  bool conversions (and, when we add !torch.int and !torch.float, it
  will handle those as well), and generalize the related utilities (I
  also moved them to Torch/Transforms since they aren't really part of
  Torch/IR).
  - Add `torch.to_i1` and `torch.from_i1` ops for materializations
- [cleanup] Reorganize `torch.constant.*` ops in TorchOps.td
- Remove dependency of `torch` dialect on `basicpy` dialect and also
  `std` dialect. For `std`, we use some call related ops, but the
  `torch` dialect itself never produces them (we have passes that do
  though).

This is fairly mechanical. Recommended review order:
- New stuff in Torch/IR
- New BuiltinTypeConversion files.
- Mechnical fixups elsewhere.
2021-06-16 13:22:00 -07:00
Sean Silva 370e3270ab Introduce `!torch.tensor` / `!torch.vtensor` types.
This removes our reliance on the numpy dialect and avoids our off-label
use of the builtin tnesor type for modeling unknown dtypes.  The
`!torch.vtensor` (`ValueTensorType`) type is a value-semantic tensor.
The `!torch.tensor` (`NonValueTensorType`) type is a non-value-semantic
tensor. The new types look as follows syntactically:

```
// Least-static-information, non-value-semantic tensor.
!torch.tensor
// Explicit form of least-static-information variant.
!torch.tensor<*,unk>
// Least-static-information, value-semantic tensor.
!torch.vtensor
// Explicit form of least-static-information variant.
!torch.vtensor<*,unk>
// Fixed-set of allowable element types, with first-class support for
// Torch's frontend signedness semantics.
!torch.tensor<*,si32>
// First-class support for unknown dtypes.
!torch.tensor<[?,?,?],unk>
// Standard MLIR representation of `?` for unknown dimensions.
!torch.tensor<[?,2,?,4],unk>
// Statically shaped / dtyped example.
!torch.vtensor<[1,2,3,4],f32>
```

This required fairly significant changes throughout the compiler, but
overall it is a big cleanup. We now have a much clearer layering of "the
Torch frontend lowering" vs "lowering to std + linalg + etc.".

At the C++ level, there is `ValueTensorType`, `NonValueTensorType`.
We also have a helper `BaseTensorType` (kind of like ShapedType) which
interoperates with those two.

Included changes:
- New `torch.tensor(dense<0.0> : tensor<5xf32>) : !torch.tensor` op for
  creating torch tensor literals in the frontend.
- Consistently use signedness for the types (except i1 which I didn't
  touch -- we need to sort out the situation with !basicpy.BoolType
  there anyway so will be attending to that soon)
- Frontend can annotate whether an argument to the function has value
  semantics. We currently require this, as our backend contract does not
  currently allow us to even model the non-value-semantic case. Before,
  the value-semantic assumption was randomly injected in the middle of
  the pass pipeline.
- Move ArrayToTensor (now called MaximizeValueSemantics) and
  RefinePublicReturn passes to torch dialect.
- The TorchToStd and TorchToLinalg passes are now type conversions from
  `!torch.vtensor` to `tensor` and use the dialect conversion infra.
  The overall conversion pipeline is set up following the best practices
  of the "Type Conversions the Not-So-Hard Way" talk. This required
  introducing `torch-func-builtin-tensorize` and
  `torch-finalizing-builtin-tensorize` passes analogous to the upstream
  bufferization passes with the corresponding names (mostly just
  copypasta from there).
- Misc Torch-level canonicalizations -- we now cleanly layer the
  lowering to std later in the pipeline, so we are gradually lessening
  our reliance on random std constant folding before we get to that
  point.

Recommended review order:
- New types in TorchTypes.td/TorchTypes.h/TorchDialect.cpp
- New ops in TorchOps.td / TorchOps.cpp
- Less important / more mechanical stuff
  - Frontend changes.
  - Pass changes/additions in `Torch/Transforms` and `Conversion/`
2021-06-10 10:56:48 -07:00
Sean Silva 2efda323ff Significantly restructure torch/aten import design.
This is a really major and invasive restructuring of the way we get
torch operators (`torch::jit::Operator` / `c10::OperatorHandle`) into
MLIR. Please forgive the challenging review, but due to the sheer
invasiveness, it wasn't really practical do do it in sane smaller
pieces.

This fully replaces everything that was already working on the
TorchScript path (actually, more -- we added tanh support to
TorchToLinalg in order to delete the older code paths). Additionally,
I've kept the lights on for the acap path too, including what little e2e
stuff was working before (for expediency I made a few tiny compromises
along the way that will be easy to undo when we give that path proper
attention).

Overview of the new design:
- The torch operator `somens::someunqualname.someoverloadname` is
  imported as `torch.somens.someunqualname.someoverloadname` (skip the
  last dotted part if the overload name is empty), OR, if we don't have
  such an op registered, it is imported as
  `torch.operator "somens.someunqualname.someoverloadname" (...) : ...`.
  - The addition of the "overload name" is a critical element here, as
    the `(ns,unqual,overload)` triple is unique, which solves a lot of
    problems we were having.
  - This involves having separate MLIR ops for the `trailing_` and
    `.out` variants and all the different overloads. This seemed
    necessary, because the set of overloads is so wild and varied and
    unstructured. The previous design was leaning into some underlying
    structure that just isn't there -- the default situation is
    the "random overload that we want to manage on the MLIR side",
    rather than that being an exception. E.g.  `aten::ne` (not-equal)
    has 21 overloads, only 4 of which are c10 dispatcher ops see
    [gist](https://gist.github.com/silvasean/190ba918c550c956260e21254e1b8aa1),
    and the "out" variant is really called `.Tensor_out` instead of
    `.out` as it frequently is for other ops.
  - Rationale for all being in `torch` namespace: the set of operators
    are so varied and unstructured that "dialect per namespace"
    doesn't result in anything resembling the typical MLIR dialect
    boundary expectations. We could maybe draw the boundary at
    dispatcher ops vs non-dispatcher ops, but that doesn't seem to
    really result in very much useful structure at this point in time.
  - Note: within the torch operator registry, we effectively have a
    mini-basicpy subdialect (already type-resolved), which is reasonably
    structured.
  - The existing Torch op interfaces are also removed -- now that we
    track the overload name, we can losslessly find the original
    operator.
- Instead of `ATenRecognizeKernelsPass`, we now have a
  `ReduceOpVariantsPass` that keys off certain traits (and perhaps
  eventually interfaces) to reduce variants of ops to a smaller set,
  ideally operating on immutable tensors and using surrounding ops to
  model the mutability/aliasing aspects.
  - Note: `torch.ns.unqual.overload` ops allow both immutable and
    mutable tensors (unlike the previous hard distinction in the common
    case). This is a premonition for a future change that will introduce a
    bona fide `!torch.tensor` type that will clean up a bunch of stuff.
- `TorchToLinalg` / `TorchToStd` supercede the existing
  "ATen->TCF->TCP->Linalg" path.
- The new `torch_ods_gen.py` supercedes `torch_signature_ods_gen.py`.
  It should look somewhat familiar, but the benefit of hindsight has
  allowed a lot of simplifications.

The overall trend seems to be to make the `torch` dialect a nice layer
independent of anything else. It feels like as a natural result of
various future changes we will be removing the reliance on basicpy+numpy
dialects and have a nice self-contained type system too that properly
models the TorchScript type system (including proper subtyping,
mutable/immutable tensors, optional dtype, etc.).

Recommended review order:
- Start at some of the new import IR, e.g. in
  `frontends/pytorch/test/node_import/prim.py`,
  `frontends/pytorch/test/acap_export/test_export_add3.py`, and other
  tests.
- `frontends/pytorch/python/torch_mlir_utils/codegen/torch_ods_gen.py`
  and associated generated files:
  - `include/npcomp/Dialect/Torch/IR/GeneratedAtenOps.td`
  - `include/npcomp/Dialect/Torch/IR/GeneratedPrimOps.td`
- Inspect `ReduceOpVariants.cpp` / `reduce-op-variants.mlir` and the new
  traits in `include/npcomp/Dialect/Torch/IR/TorchTraits.h`
- Various code changes in the import path in
  `frontends/pytorch/csrc/builder`. Probably most interesting is the new
  code in `torch_to_mlir_utils.cpp` that has the logic to create the
  `torch.operator` ops or `torch.ns.unqual.overload` ops.

This is the [new ResNet IR](https://gist.github.com/silvasean/5407aafb710d07612b7b5b92eabecebe),
just to be able to look at a substantial sample of IR in the new style.
2021-05-19 13:37:39 -07:00