Skip to content

Fix 0-d tensors, dynamic output sizes and integer reductions, and default to float32 on CPU, in the OpenVINO backend - #24377

Open
pytorchbot wants to merge 34 commits into
release/1.6from
cherry-pick-24294-by-pytorch_bot_bot_
Open

pytorchbot wants to merge 34 commits into
release/1.6from
cherry-pick-24294-by-pytorch_bot_bot_

Conversation

@pytorchbot

@pytorchbot pytorchbot commented Oct 31, 2026 •

Copy link
Copy Markdown
Collaborator

What is wrong today

The OpenVINO backend has these problems:

  1. A 0-d (scalar) input or output fails on every run, because OpenVINO's ov_shape_create refuses rank 0.
  2. A float32 program does not compute in float32 on many CPUs. OpenVINO picks bfloat16 (two to three significant digits) on x86 CPUs with bfloat16 hardware and float16 on ARM CPUs, and no compile spec can change it.
  3. An output whose size depends on an int input keeps its largest size. x[:n].view(n, -1) with x of shape (4, 8) and n = 3 returns (4, 8).
  4. cumsum and prod of a bool or integer tensor are not computed in int64, as PyTorch does. A cumsum over a bool mask wraps after 255, so pi0 and pi0.5 get wrong position ids and wrong actions.

What this change does

  • 0-d tensors: a rank-0 tensor keeps its empty shape, which OpenVINO accepts.

  • Precision: when the device is CPU, a program computes in float32 by default, both when it is lowered and when it is loaded. A program can ask for a faster precision:

    OpenvinoPartitioner(
        [CompileSpec("device", b"CPU"), CompileSpec("inference_precision", b"bf16")]
    )

    The value is f32, f16 or bf16, checked before conversion starts. Other devices keep OpenVINO's default. On x86 CPUs OpenVINO applies the precision when the runtime loads the program, so the runtime passes it on too.

  • Dynamic output sizes: an output whose size can change goes to a buffer that OpenVINO owns, reused by every call. It starts empty along each dynamic dimension, and OpenVINO grows it to the largest size a call writes, so a large upper bound costs nothing until a call needs it. After inference the backend resizes the ExecuTorch output to OpenVINO's shape and copies the data in, so one delegate can also serve several calls, as programs from ExecuTorch 0.7 and earlier do. Static outputs still use the ExecuTorch buffer directly.

  • Integer reductions: the input of cumsum and prod is cast to int64 before conversion. An integer cumsum that reads only constants is computed during lowering, because OpenVINO's CPU plugin gives it wrong results from the second inference on. This includes a cumsum over ones_like or zeros_like of an input with a static shape, which OpenVINO folds into a constant too. Each one is folded on its own, and one that cannot be folded is named in a warning.

Trade-offs:

  • float32 is slower. On a Xeon with bfloat16 hardware, a 4-layer MLP takes 2.4 ms in float32 and 1.5 ms in bfloat16. On x86 CPUs with bfloat16 units this also applies to programs exported before this change, because OpenVINO applies the precision when a program loads. To get the old speed, export again with inference_precision set to bf16.
  • OpenVINO's CPU plugin computes int64 in 32 bits, so an integer result past the int32 range wraps without an error. That was already true for int64 programs, and now also applies to cumsum and prod over smaller integer types.

Tests

Each new test fails without its fix: 0-d inputs and outputs; a 256 x 256 addmm checked to 1e-4, and the same addmm lowered with bf16 checked not to reach 1e-4, so the runtime must apply an explicit precision (both skipped where OpenVINO already computes in float32); an unknown precision refused before conversion; dynamic output sizes, on one program and on one delegate shared by two calls; bool and int32 cumsum, and int32 prod; pi0-style masks with int64 and int32 cumsums over two calls, built from a constant and from ones_like; and folding when one cumsum cannot be evaluated. The tests for integer sum, which OpenVINO already counts past 255, and for a static output after a dynamic view are guards that pass either way.

The full OpenVINO op suite passes on Linux x86_64 (a CPU with bfloat16 units) with OpenVINO 2026.4.1, through both pytest and the CI test runner. With OpenVINO 2025.1.0 it also passes, except that the prod test is skipped because that release does not delegate prod.

Follow-up fix from #24305

This pick also carries the test runner fix from #24305. When a test failed, the OpenVINO test runner printed "completed with failures" but still exited with code 0, so the CI job stayed green. It now exits with code 1 when a test fails, so the job fails.

Follow-up fixes from #24396

This pick also carries these fixes from #24396 for code that #24294 added:

  • When a folded cumsum was the only reader of the first partition input, OpenVINO's converter dropped that input, and every call failed. Lowering now puts it back. If the converted model still takes a different number of inputs, lowering now fails with a clear error.
  • With Fix 0-d tensors, dynamic output sizes and integer reductions, and default to float32 on CPU, in the OpenVINO backend #24294, an output that ExecuTorch plans with a dynamic size but OpenVINO compiles with a fixed shape failed on every call. Its buffer now starts with the compiled shape.
  • Inside with torch.device("cuda"):, the cumsum fold put a temporary tensor on the default device, so lowering failed on a CPU-only PyTorch. It now makes that tensor on the CPU.
  • When inference_precision was given twice and the last value was empty, the runtime used the earlier value while lowering used the default. The runtime now takes the last value too.

It also carries a fix for an older bug. min, max, amin, amax, minimum, maximum, clamp and sign that read only bool tensors made the whole program fail to lower, because the OpenVINO operations they become do not take bool tensors. The partitioner now leaves them to the CPU. With PyTorch 2.15, MultivariateNormal exports such a min when it checks scale_tril.

The OpenVINO CI script now runs the model tests even when an op test fails, and still fails the job.

The matching tests, comment and doc fixes, and small cleanups of the cumsum fold and the new output buffer code come from the same PR. With all of them, the OpenVINO op and model tests pass on Linux x86_64 with OpenVINO 2026.4.1, and with 2025.1.0 apart from the skipped prod test.

Merge order

This branch is stacked on #24298, the pick of #24222, and contains all of its commits. Merge #24298 first: merging this PR first would land #24298's changes too. #24396 is still open on main, and it should land there before this PR merges.

…and in exir (#24222)

Fixes found while exporting models to ExecuTorch backends.

## Fixes

- **exir:** `constant_prop_pass` keeps tensors that in-place ops write,
also through views or in `no_grad`/`autocast` blocks. `to_backend` keeps
the output node last. `to_edge` lowers `torch._check_tensor_all` and
`torch.sym_ite`. `GroupBasedPartitioner` no longer makes partitions that
depend on each other, unless caller node groups already do. Tensor
constants get static shapes; deduplicated constants keep their data.
- **AOTI (AOTInductor) and CUDA:** the missing-kernel check catches
scatter and index_put fallbacks. `detach` lowers, also inside
`torch.cond`. Strided outputs are copied. Transposed convolutions (1-D,
2-D, no dilation) and `torch._check_tensor_all` lower.
- **XNNPACK:** the quantizer skips bfloat16 tensors, and `cat` respects
scoped configs. ELU is delegated when XNNPACK can run it.
- **Qualcomm:** autocast regions are inlined correctly. Unquantized
bfloat16 nodes, data-dependent shapes and HTP partitions without runtime
inputs stay on the CPU. Fixes for stacks, 0-d selects, RMSNorm and int64
constants.
- **OpenVINO:** model data stays alive while OpenVINO 2026.4 reads it.
Partitions are converted with their input types.
- **Core ML:** bfloat16 ops, and ops above rank 5 outside static layout
chains, stay on the CPU.
- **MLX, Arm, Cortex-M, Vulkan, NXP, portable:** dtype checks for MLX
tensor lists, one constant slot per weight, slice updates on a constant
base; TOSA keeps unused delegate inputs for VGF; `MatmulToBmmPass` takes
a constant operand; Vulkan constants above 4 dims; non-strict programs
in the NXP quantizer; `cummin.out`.

## Behavior changes

- A CUDA `.pte` loads only the weights it was exported with. A `.ptd`
with other weights, for example after fine-tuning, needs a newly
exported `.pte`.
- CUDA graphs turn off when outputs do not match the ETensor layout. If
only the capture call sees such a layout, that call returns an error.
- `GroupBasedPartitioner` is about 2x slower on large graphs, and some
graphs get a different number of partitions. `to_backend` keeps the
original order of top-level nodes.
- XNNPACK: weight-only quantized linears, and 8da4w or 8da8w linears
(8-bit dynamic activations, 4-bit or 8-bit weights) lowered with
`to_backend`, fail at export instead of giving wrong results. Delegated
ELU flushes subnormal values to zero. Cats outside a scoped quantizer
config are no longer quantized.
- Ethos-U raises an error for a delegate with unused inputs instead of
returning wrong values.

We would like to cherry-pick this PR to release/1.6 after it merges. It
needs #23915 there first.

## Testing

Each fix has a test that fails without it. Run on an A100 (CUDA,
Vulkan), an x86 CPU (OpenVINO, QNN SDK), macOS (Core ML, MLX), the TOSA
reference model and VGF emulation (Arm), and the eIQ Neutron SDK (NXP).
Not run: Metal, ROCm, Windows CUDA.

(cherry picked from commit 054de1f)
This branch was picked before #24263 and #24295 reached release/1.6, so
three files carried their content only in part. Take release/1.6 and use
the versions a clean pick of 054de1f gives for
backends/qualcomm/partition/qnn_partitioner.py,
backends/qualcomm/tests/test_passes.py and exir/tests/test_pass_infra.py.
release/1.6 regenerated aoti_cuda_shims.lib to add
aoti_torch_dtype_element_size, and this branch regenerated it to add
aoti_torch_as_strided. Regenerate it per aoti_cuda_shims.lib.md with both
names, so it lists exactly the shims this tree exports.
…ault to float32 on CPU, in the OpenVINO backend (#24294)

## What is wrong today

The OpenVINO backend has these problems:

1. A 0-d (scalar) input or output fails on every run, because OpenVINO's
`ov_shape_create` refuses rank 0.
2. A float32 program does not compute in float32 on many CPUs. OpenVINO
picks bfloat16 (two to three significant digits) on x86 CPUs with
bfloat16 hardware and float16 on ARM CPUs, and no compile spec can
change it.
3. An output whose size depends on an int input keeps its largest size.
`x[:n].view(n, -1)` with x of shape (4, 8) and n = 3 returns (4, 8).
4. `cumsum` and `prod` of a bool or integer tensor are not computed in
int64, as PyTorch does. A cumsum over a bool mask wraps after 255, so
pi0 and pi0.5 get wrong position ids and wrong actions.

## What this change does

- **0-d tensors:** a rank-0 tensor keeps its empty shape, which OpenVINO
accepts.
- **Precision:** when the device is `CPU`, a program computes in float32
by default, both when it is lowered and when it is loaded. A program can
ask for a faster precision:

  ```python
  OpenvinoPartitioner(
[CompileSpec("device", b"CPU"), CompileSpec("inference_precision",
b"bf16")]
  )
  ```

The value is `f32`, `f16` or `bf16`, checked before conversion starts.
Other devices keep OpenVINO's default. On x86 CPUs OpenVINO applies the
precision when the runtime loads the program, so the runtime passes it
on too.
- **Dynamic output sizes:** an output whose size can change goes to a
buffer that OpenVINO owns, reused by every call. It starts empty and
OpenVINO grows it to the largest size a call writes, so a large upper
bound costs nothing until a call needs it. After inference the backend
resizes the ExecuTorch output to OpenVINO's shape and copies the data
in, so one delegate can also serve several calls, as programs from
ExecuTorch 0.7 and earlier do. Static outputs still use the ExecuTorch
buffer directly.
- **Integer reductions:** the input of `cumsum` and `prod` is cast to
int64 before conversion. An integer cumsum that reads only constants is
computed during lowering, because OpenVINO's CPU plugin gives it wrong
results from the second inference on. This includes a cumsum over
`ones_like` or `zeros_like` of an input with a static shape, which
OpenVINO folds into a constant too. Each one is folded on its own, and
one that cannot be folded is named in a warning.

Trade-offs:
- float32 is slower. On a Xeon with bfloat16 hardware, a 4-layer MLP
takes 2.4 ms in float32 and 1.5 ms in bfloat16. On x86 this also applies
to programs exported before this change, because OpenVINO applies the
precision when a program loads. To get the old speed, export again with
`inference_precision` set to `bf16`.
- OpenVINO's CPU plugin computes int64 in 32 bits, so an integer result
past the int32 range wraps without an error. That was already true for
int64 programs, and now also applies to `cumsum` and `prod` over smaller
integer types.

## Tests

Each new test fails without its fix: 0-d inputs and outputs; a 256 x 256
addmm checked to 1e-4, and the same addmm lowered with `bf16` checked
not to reach 1e-4, so the runtime must apply an explicit precision (both
skipped where OpenVINO already computes in float32); an unknown
precision refused before conversion; dynamic output sizes, on one
program and on one delegate shared by two calls; bool and int32 cumsum
and prod; pi0-style masks with int64 and int32 cumsums over two calls,
built from a constant and from `ones_like`; and folding when one cumsum
cannot be evaluated. Two guards pass either way: integer `sum`, which
OpenVINO already computes in int64, and a static output after a dynamic
view.

The full OpenVINO op suite passes on Linux x86_64 (a CPU with bfloat16
units) with OpenVINO 2026.4.1, through both pytest and the CI test
runner. With OpenVINO 2025.1.0 it also passes, except that the prod test
is skipped because that release does not delegate prod.

(cherry picked from commit 7b14148)
@pytorch-bot

pytorch-bot Bot commented Oct 31, 2026 •

Copy link
Copy Markdown

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/24377

Note: Links to docs will display an error until the docs builds have been completed.

❌ 2 New Failures, 1 Cancelled Job, 1 Unclassified Failure

As of commit f2cf062 with merge base 4db778e (image):

NEW FAILURES - The following jobs have failed:

UNCLASSIFIED FAILURE - DrCI could not classify the following job because the workflow did not run on the merge base. The failure may be pre-existing on trunk or introduced by this PR:

CANCELLED JOB - The following job was cancelled. Please retry:

This comment was automatically generated by Dr. CI and updates every 15 minutes.

@meta-cla meta-cla Bot added the CLA Signed This label is managed by the Facebook bot. Authors need to sign the CLA before a PR can be reviewed. label Oct 31, 2026
@JacobSzwejbka JacobSzwejbka reopened this Oct 31, 2026
…ault to float32 on CPU, in the OpenVINO backend (#24294)

## What is wrong today

The OpenVINO backend has these problems:

1. A 0-d (scalar) input or output fails on every run, because OpenVINO's
`ov_shape_create` refuses rank 0.
2. A float32 program does not compute in float32 on many CPUs. OpenVINO
picks bfloat16 (two to three significant digits) on x86 CPUs with
bfloat16 hardware and float16 on ARM CPUs, and no compile spec can
change it.
3. An output whose size depends on an int input keeps its largest size.
`x[:n].view(n, -1)` with x of shape (4, 8) and n = 3 returns (4, 8).
4. `cumsum` and `prod` of a bool or integer tensor are not computed in
int64, as PyTorch does. A cumsum over a bool mask wraps after 255, so
pi0 and pi0.5 get wrong position ids and wrong actions.

## What this change does

- **0-d tensors:** a rank-0 tensor keeps its empty shape, which OpenVINO
accepts.
- **Precision:** when the device is `CPU`, a program computes in float32
by default, both when it is lowered and when it is loaded. A program can
ask for a faster precision:

  ```python
  OpenvinoPartitioner(
[CompileSpec("device", b"CPU"), CompileSpec("inference_precision",
b"bf16")]
  )
  ```

The value is `f32`, `f16` or `bf16`, checked before conversion starts.
Other devices keep OpenVINO's default. On x86 CPUs OpenVINO applies the
precision when the runtime loads the program, so the runtime passes it
on too.
- **Dynamic output sizes:** an output whose size can change goes to a
buffer that OpenVINO owns, reused by every call. It starts empty and
OpenVINO grows it to the largest size a call writes, so a large upper
bound costs nothing until a call needs it. After inference the backend
resizes the ExecuTorch output to OpenVINO's shape and copies the data
in, so one delegate can also serve several calls, as programs from
ExecuTorch 0.7 and earlier do. Static outputs still use the ExecuTorch
buffer directly.
- **Integer reductions:** the input of `cumsum` and `prod` is cast to
int64 before conversion. An integer cumsum that reads only constants is
computed during lowering, because OpenVINO's CPU plugin gives it wrong
results from the second inference on. This includes a cumsum over
`ones_like` or `zeros_like` of an input with a static shape, which
OpenVINO folds into a constant too. Each one is folded on its own, and
one that cannot be folded is named in a warning.

Trade-offs:
- float32 is slower. On a Xeon with bfloat16 hardware, a 4-layer MLP
takes 2.4 ms in float32 and 1.5 ms in bfloat16. On x86 this also applies
to programs exported before this change, because OpenVINO applies the
precision when a program loads. To get the old speed, export again with
`inference_precision` set to `bf16`.
- OpenVINO's CPU plugin computes int64 in 32 bits, so an integer result
past the int32 range wraps without an error. That was already true for
int64 programs, and now also applies to `cumsum` and `prod` over smaller
integer types.

## Tests

Each new test fails without its fix: 0-d inputs and outputs; a 256 x 256
addmm checked to 1e-4, and the same addmm lowered with `bf16` checked
not to reach 1e-4, so the runtime must apply an explicit precision (both
skipped where OpenVINO already computes in float32); an unknown
precision refused before conversion; dynamic output sizes, on one
program and on one delegate shared by two calls; bool and int32 cumsum
and prod; pi0-style masks with int64 and int32 cumsums over two calls,
built from a constant and from `ones_like`; and folding when one cumsum
cannot be evaluated. Two guards pass either way: integer `sum`, which
OpenVINO already computes in int64, and a static output after a dynamic
view.

The full OpenVINO op suite passes on Linux x86_64 (a CPU with bfloat16
units) with OpenVINO 2026.4.1, through both pytest and the CI test
runner. With OpenVINO 2025.1.0 it also passes, except that the prod test
is skipped because that release does not delegate prod.

(cherry picked from commit 7b14148)
shoumikhin and others added 2 commits October 31, 2026 01:01
The pick was made on release/1.6, which does not have #24298 (the #24222
pick) yet. #24294 builds on #24222, so the pick depends on code that
release/1.6 lacks, such as _nodes_written_in_place in exir's
constant_prop_pass, and its conflict resolution brought in some of
#24222's OpenVINO changes but not others. This merges a clean pick of
7b14148 onto #24298's branch and takes the clean pick's side in the
OpenVINO files, so that, on top of #24298, the change is exactly #24294
(7b14148). A plain merge of the two would keep two copies of
_PRECISIONS in preprocess.py.
The OpenVINO CI job runs backends/openvino/tests/test_runner.py. When a test
failed, the runner printed "completed with failures" but still exited with
code 0, so the CI job stayed green and the failure went unnoticed.

Now the runner exits with code 1 when any test fails, so CI turns red. This
is the test runner fix from #24305.

Co-authored-by: suryasidd <surya.siddharth.pemmaraju@intel.com>
…_precision

The check that the runtime takes the last inference_precision entry ran
only on x86 CPUs with bfloat16 units, so CI could skip it. A new test
gives an invalid value and then an empty one. Lowering keeps only the
empty one, and the runtime has to as well, or it fails to load the
program. On the runtime before that fix it fails with "unsupported
inference_precision 'f7'".
…ioner

OpenVINO converts min, max, amin, amax, minimum, maximum, clamp and sign
to its ReduceMin, ReduceMax, Minimum, Maximum and Sign operations, and
none of those accept bool tensors. The partitioner still gave these ops
to OpenVINO when they read bool tensors, so the whole program failed to
lower:

    ReduceMin ... Element type of data input must be numeric. Got: boolean

With PyTorch 2.15, MultivariateNormal exports two such mins when it
checks scale_tril, so a model that builds one could not use OpenVINO.

The partitioner now leaves these ops to the CPU when every tensor they
read is bool, and the portable kernels compute them as PyTorch does. An
op with a bool and a float input, such as maximum(mask, x), is computed
in float, which OpenVINO converts, so it stays with OpenVINO. Other
dtypes are not affected.
Lowering passes the precision too, so the comment was wrong to say only
the runtime does. What makes the check depend on the runtime is that on
x86 OpenVINO applies only the precision it gets when it loads the model.
The cumsum fold lines had landed between the comment and the decoder
call it explains, so the comment read as if it were about the fold.
Since each cumsum is folded on its own, _evaluate is only ever asked for
one node. Taking and returning that one value drops the list and dict it
no longer needs, and a check that could never be false.
Only the attention mask test covered an int32 cumsum, and only through
an OpenVINO CPU bug that newer OpenVINO releases fix. A fold limited to
int64 now fails a pass-level test too.
Only x86 CPUs with bfloat16 units computed in bfloat16 before, so only
they get slower, and only there does asking for bf16 bring the earlier
speed back. On other x86 CPUs OpenVINO already computed in float32.
The precision docs said int64 results only go wrong outside the int32
range. Measured through the delegate on a CPU, an int64 sum is computed
in float32: 16777216 + 1 gives 16777216, and 123456789 + 987654321 gives
1111111168. cumsum and prod near 2^24 stay exact.
Only an output compiled with a fully fixed shape refuses a buffer of another shape. A partly dynamic output accepts an empty one. Comment only.
OpenVINO 2025.1 has the same CPU plugin bug with integer cumsums over constants as the later releases, so the fold's docstring now starts the range there. Docstring only.
The OpenVINO CI job runs the op tests and then the model tests under
set -e. Now that the test runner exits with code 1 when a test fails, a
failing op test stopped the job before the model tests started, so a red
run said nothing about the models. The script now runs both suites and
exits with code 1 if either failed.
Preprocess put the first partition input back whenever the converted
model had one parameter fewer than the partition has inputs. Now it does
so only when that first input is really unused, and lowering fails when
the counts still differ. The runtime binds inputs by position, so another
mismatch would have made every call fail, or swapped two inputs of the
same type and shape. A partition can also have no inputs at all, such as
a comparison that reads only a buffer next to a bool min on the CPU, and
a test covers that case.
TestBoolMinMax compared only the values of min(dim) and max(dim). Their
indices are where the order of ties matters, and the all-true and
all-false rows are all ties, so the test now compares the indices with
eager too. Its docstring also says more exactly why these ops leave
OpenVINO.
x was int64 in both subtests, so the result was int64 whatever dtype the
folded cumsum had, and a fold that dropped dtype=torch.int32 still
passed. x now has the subtest's dtype, so such a fold fails the int32
subtest.
The docs said only sum reduces integers in float32. Measured through the
delegate on a CPU with OpenVINO 2026.4.1 and 2025.1.0, amax, amin, max and
min of int32 and int64 tensors do too: amax over a tensor that holds
16,777,217 gives 16,777,216. Inputs and running totals round as well, so
the sum of 16,777,217 and -16,777,216 gives 0. cumsum and maximum stay
exact, and so does prod where OpenVINO computes it (2026.4.1).

This branch was successfully deployed

1 active and 1 inactive deployments
upload-benchmark-results — f2cf062f Deployed Nov 1, 2026 by shoumikhin via upload-benchmark-results #21695
cadence — f2cf062f Deployed Nov 1, 2026 by shoumikhin via hifi-op-test / hifi4 #35811
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

ciflow/trunk CLA Signed This label is managed by the Facebook bot. Authors need to sign the CLA before a PR can be reviewed. module: arm Issues related to arm backend

Projects

None yet

Development

Successfully merging this pull request may close these issues.

3 participants