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jk don't apply passes#18897

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jk don't apply passes#18897
ryan-monroe wants to merge 2 commits intopytorch:mainfrom
ryan-monroe:export-D100874753

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@ryan-monroe ryan-monroe commented Apr 14, 2026

Differential Revision: D100874753

@ryan-monroe @facebook-github-bot
Add FuseConcatPass to eliminate redundant concat ops (pytorch#18827)
bcbf705 
Summary:

Concat (torch.cat) in the Gen2 Executorch ARM/Ethos-U stack is lowered to
TOSA CONCAT, which Vela then converts to N x MemoryCopy operations — real
DMA data movement on the NPU. This pass eliminates concat operations that
can be proven unnecessary at the FX graph level, preventing Vela from
generating MemoryCopy ops entirely.

Inspired by Espresso's concat elimination techniques
(bolt/nn/espresso/transforms/remove_nops.py), three patterns are handled:

1. Single-input concat: cat([x]) is a no-op, replaced with x.
2. Concat-then-slice: if every consumer of cat([a, b, ...]) is a
   slice_copy that extracts exactly one original input, bypass both.
3. Slice-then-concat: if contiguous slices of the same tensor are
   concatenated back, the result is the original tensor.

Differential Revision: D97667069
@ryan-monroe @facebook-github-bot
jk don't apply passes
7eae5de 
Differential Revision: D100874753
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pytorch-bot bot commented Apr 14, 2026 •
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🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/18897

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

❗ 1 Active SEVs

There are 1 currently active SEVs. If your PR is affected, please view them below:

❌ 2 Awaiting Approval, 2 New Failures, 2 Unrelated Failures

As of commit 7eae5de with merge base 75c677f (image):

AWAITING APPROVAL - The following workflows need approval before CI can run:

NEW FAILURES - The following jobs have failed:

BROKEN TRUNK - The following jobs failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

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 Apr 14, 2026
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meta-codesync bot commented Apr 14, 2026

@ryan-monroe has exported this pull request. If you are a Meta employee, you can view the originating Diff in D100874753.

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github-actions bot commented Apr 14, 2026

This PR needs a release notes: label

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