[Bugfix] Fix non-divisible nested modulo simplification

[haoyang9804]

Summary

• update the bundled TVM iter-map simplifier to preserve a nested modulo when the inner split can wrap and its extent is not divisible by the outer modulus
• retain the valid simplification for non-wrapping and divisible cases
• add mirrored TileLang regression coverage

This prevents (x % 64) % 7 from being incorrectly rewritten as x % 7 during FlattenBuffer.

Depends on tile-ai/tvm#64.

Fixes #2955.

Testing

• native build passed
• TVM arithmetic suite: 39 passed
• TileLang arithmetic suite: 39 passed
• Metal codegen retains (threadIdx.x & 63) % 7

Summary

• Updated the bundled TVM revision to preserve nested modulo expressions when divisibility is not proven.
• Prevented (x % 64) % 7 from simplifying incorrectly to x % 7.
• Added regression coverage for divisible and non-divisible extents.
• Native build, TVM arithmetic, TileLang arithmetic, and Metal codegen tests pass.

C++ style / lint notes

• The PR updates bundled TVM C++ code through a submodule revision.
• It does not modify docs/developer_guide/cpp_style.md.
• No new correctness or build issues are reported.
• Any C++ API Style Audit findings are warning-only and do not block the change.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Run ID: 6cd86b84-e2bd-48e0-afd7-3b7153bc28fb

📥 Commits

Reviewing files that changed from the base of the PR and between f5c3614 and f8fd99e.

📒 Files selected for processing (1)

• 3rdparty/tvm

🚧 Files skipped from review as they are similar to previous changes (1)

• 3rdparty/tvm

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📝 Walkthrough

Walkthrough

The vendored TVM revision was updated. Regression coverage was added for nested floormod simplification with divisible and non-divisible extents.

Changes

Nested floormod correctness

Layer / File(s)	Summary
TVM revision and floormod regression coverage 3rdparty/tvm, testing/python/arith/test_arith_iter_affine_map.py	The TVM submodule reference now uses a newer revision. Tests verify that non-divisible nested modulo expressions remain unchanged and divisible expressions simplify to x % 8.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to f8fd9

This localized fix preserves nested modulo behavior for wrapping, non-divisible cases while retaining valid simplifications elsewhere, with regression coverage and passing test suites. No actionable merge-blocking risk remains beyond normal checks and review.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 1 files. (1 skipped: 1 …	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly identifies the main change: fixing incorrect simplification of non-divisible nested modulo expressions.
Linked Issues check	✅ Passed	The submodule update brings the TVM simplifier fix, and the added regression test covers divisible and non-divisible nested modulo behavior. These changes address the requirements in [#2955].
Out of Scope Changes check	✅ Passed	The changes are limited to the TVM submodule update and focused regression coverage. Both changes support the linked issue objectives.

Full details: Docstring Coverage

Explanation

Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 1 files. (1 skipped: 1 unsupported.)

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[github-actions]

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[LeiWang1999]

Thanks! The TVM-side fix has been merged via tile-ai/tvm#65.

This PR now updates 3rdparty/tvm from the previous PR head (1b372fa482cf) to the merged tilelang_main commit (121df796b1b3). The update is included in commit f8fd99ef.