Physicalize MX scale tensor views in BlockMxScaleTensorViews

[yanghaoran29]

Summary

• Add a dedicated pass 15, BlockMxScaleTensorViews, immediately after the NZ-only BlockNzTensorViews pass. It converts logical rank-2 MX_A_ZZ / MX_B_NN scale tensors and tile.load windows into canonical packed rank-5 IR.
• Keep MX alignment and non-negativity reasoning private to the new pass (MxOffsetFacts and its bounded proof walkers), including propagation through outlined scalar parameters and every Call / Submit site.
• Preserve ND/MX aliases, function and Submit return types, valid shapes, launch fields, and pass idempotence; reject dynamic offsets whose MX alignment cannot be proved.
• Split the MX coverage into test_block_mx_scale_tensor_views.py, leave the NZ test unchanged, document the new pass in English and Chinese, and renumber the following pass documentation from 16 through 50.

MX physical-view migration

This PR migrates MX logical-to-physical view lowering from the backend helper EmitMxPhysicalView into the new BlockMxScaleTensorViews pass; it does not classify MX as NZ and does not remove MX support.

Before this PR, src/backend/common/pto_ops_memory.cpp kept MX tensors logically rank-2 through the IR and constructed the packed rank-5 make_tensor_view only while emitting tile.load. That backend-only path required constant shapes and offsets, so it could not accept symbolic offsets even when their alignment was provable.

After this PR:

1. Pass 14 remains NZ-only.
2. Pass 15 proves MX-specific offset facts and materializes canonical rank-5 MX tensor views in IR.
3. MaterializeTensorStrides derives the physical row-major strides from that shape.
4. PTO codegen consumes the canonical IR through the generic make_tensor_view and partition_view path.

The physical descriptor remains [1, block_count, group_count, 16, 2]; ownership moves from a tile.load-local backend special case to an explicit MX pass that consistently covers parameters, aliases, calls, returns, verification, and codegen.

Testing

• Native build succeeds.
• 143 focused MX/NZ/pass-manager/operator/codegen/verifier tests pass; the standalone MX pass file has 9 focused cases.
• Complete pre-commit passes, including C++/Python formatting, lint, typing, and documentation consistency checks.
• Downstream acceptance for hw-native-sys/pypto-lib#1109: expert_shared.py and expert_routed.py both report [RUN] PASS on A5sim and allocated real A5 devices with PTOAS v0.57.
• Full local unit run: 11,180 passed, 60 skipped, 1 xfailed; the remaining 6 failures are local-environment import/debug-path issues outside the changed areas.

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Walkthrough

Changes

MX tensor view pipeline

Layer / File(s)	Summary
MX blocking and offset rewriting src/ir/transforms/block_nz_tensor_views_pass.cpp, tests/ut/ir/transforms/test_block_nz_tensor_views.py, docs/en/dev/passes/14-block_nz_tensor_views.md, docs/zh/dev/passes/14-block_nz_tensor_views.md	The pass blocks MX tensors into rank-5 shapes, rewrites load windows and offsets, validates provability, preserves narrowed valid shapes, and tracks separate NZ and MX completion markers.
Blocked MX IR validation src/ir/op/tile_ops/memory.cpp, src/ir/transforms/materialize_tensor_strides_pass.cpp	MX loads and tensor types validate blocked rank-5 views. Stride materialization checks MX shapes before processing.
Generic MX view code generation src/backend/common/pto_ops_memory.cpp, src/codegen/pto/pto_codegen.cpp, tests/ut/codegen/test_mx_ops_codegen.py	MX parameters and loads use generic pto.make_tensor_view and partition_view code generation. Dedicated MX physical-view emission is removed. Tests cover alignment proofs and rejected offsets.

Estimated code review effort: 4 (Complex) | ~45 minutes

Merge Risk: 🟠 High · up to adb55

MX loads may use incorrect packed coordinates or invalid SFractal windows, risking wrong memory accesses. Fix these issues before merge.

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🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 36.51% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 63 functions across 9 files. (2 skipped: …	Write docstrings for the functions missing them to satisfy the coverage threshold.
Title check	⚠️ Warning	The title identifies the MX scale tensor view physicalization, but it names a dedicated BlockMxScaleTensorViews pass that is not present. The change extends BlockNzTensorViews instead.	Rename the title to reflect the actual implementation, for example: "Extend BlockNzTensorViews to physicalize MX scale tensor views".

✅ Passed checks (3 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description check	✅ Passed	The description is related to the MX tensor view lowering changes, but it incorrectly describes a new pass 15 and other changes not shown in the pull request summary.

Full details: Docstring Coverage

Explanation

Docstring coverage is 36.51% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 63 functions across 9 files. (2 skipped: 2 unsupported.)

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Inline comments:
In `@src/ir/op/tile_ops/memory.cpp`:
- Around line 268-274: Extend the blocked MX validation near the rank-5 checks
to enforce canonical window geometry: shapes must end in 16x2, trailing offsets
must be zero, and valid_shape must retain the complete trailing 16x2 transfer
window. Reject noncanonical geometry before generic codegen while preserving the
existing rank validation and diagnostic context.

In `@src/ir/transforms/block_nz_tensor_views_pass.cpp`:
- Line 159: Remove the structural-shape early returns from the initial
transformation paths: the IsBlockedNzShape check at
src/ir/transforms/block_nz_tensor_views_pass.cpp:159 and the corresponding MX
check at src/ir/transforms/block_nz_tensor_views_pass.cpp:207. Make idempotence
rely on the function stamp or explicit phase metadata so
BlockNzShape/BlockMxShape and the associated tile-load argument rewriting still
perform validation and coordinate conversion.

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📥 Commits

Reviewing files that changed from the base of the PR and between c2414da and adb55ab.

📒 Files selected for processing (11)

• docs/en/dev/passes/14-block_nz_tensor_views.md
• docs/zh/dev/passes/14-block_nz_tensor_views.md
• include/pypto/ir/tile_view_semantics.h
• include/pypto/ir/transforms/utils/tensor_view_semantics.h
• src/backend/common/pto_ops_memory.cpp
• src/codegen/pto/pto_codegen.cpp
• src/ir/op/tile_ops/memory.cpp
• src/ir/transforms/block_nz_tensor_views_pass.cpp
• src/ir/transforms/materialize_tensor_strides_pass.cpp
• tests/ut/codegen/test_mx_ops_codegen.py
• tests/ut/ir/transforms/test_block_nz_tensor_views.py

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