fix(ir): Preserve TaskId temp deps in auto derivation

[sunkaixuan2018]

Summary

• Track Array[TASK_ID] and scalar TaskId lineage through auto dependency derivation.
• Preserve manual scopes for TaskId-array temp deps used by Qwen decode, while rejecting unrelated direct submit deps as dynamic-producer coverage.
• Add regression coverage for full TaskId-array deps, scalar temp deps, partial fallback, and unrelated deps fallback.

Testing

• Remote myserver: rebuilt build-native and copied fresh pypto_core into the branch .venv.
• Remote pytest: tests/ut/ir/transforms/test_auto_derive_task_dependencies.py -> 36 passed.
• Remote Qwen3 14B decode: models/qwen3/14b/decode_layer.py -d {} --enable-l2-swimlane -> PASS.
• Fresh L2 artifact: /data/sunkaixuan/skx_log_output/issue1744/qwen_decode_nonsubmit_20260611_203215/merged_swimlane_20260611_203238.json.
• L2 concurrency spot check: out_proj 24/50, gate_proj 14/85, up_proj 15/85, down_proj 24/85, down_cast_residual 5/5.

Related Issues

Fixes #1744

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📝 Walkthrough

Walkthrough

The PR extends the AutoDeriveTaskDependencies compiler pass to resolve task-id dependencies expressed through pl.array[TASK_ID] elements, preventing incorrect demotion of user-written pl.manual_scope() to AUTO scope. The implementation adds lineage tracking for array task-ids, updates loop propagation and canonicalization logic, and includes comprehensive test coverage.

Changes

Task-ID Array Lineage Support

Layer / File(s)	Summary
Helper utilities and collector task-id recording src/ir/transforms/auto_derive_task_dependencies_pass.cpp	Adds utility functions to identify task-id scalars/arrays, extract constant values and extents, merge unique task-id sets, and detect multi-slot dynamic coverage. Extends SubmitTaskIdCollector to record task-id producers for both array and scalar forms alongside existing tuple task-id recording.
Lineage-driven data structures and accessors src/ir/transforms/auto_derive_task_dependencies_pass.cpp	Replaces scalar-only task-id mappings with lineage-based structures: task-id vectors per var-id, dynamic producer slot sets, task-id array extents, and expanded array candidates. Introduces new lineage structs for expression and array propagation that enable task-id resolution through array access patterns.
Lineage-based task-id resolution and array expansion src/ir/transforms/auto_derive_task_dependencies_pass.cpp	Implements TaskIdsForExpr to derive task-id vectors and dynamic slot sets from canonical task-id vars, mapped var-derived task-ids, or array.get_element expansion. Adds ExpandTaskIdArray to conditionally expand array task-ids when lineage is known (direct writes, dynamic loop writes, per-element composition) and multi-slot coverage is satisfied.
Loop-carried task-id array propagation and collector state src/ir/transforms/auto_derive_task_dependencies_pass.cpp	Updates loop-carried task-id handling to propagate task-id arrays by lineage and derive expansions for iter args and return vars. Rewrites producer/extent recording logic to distinguish task-id arrays and task-id scalars, replacing prior scalar-only internal state mappings with new vector/dynamic-slot/extent/lineage representations.
Canonicalization and hazard edge coverage logic src/ir/transforms/auto_derive_task_dependencies_pass.cpp	Reworks dependency canonicalization to operate on vectors of task-ids rather than single scalars. Adds dynamic-array slot-based merging and array task-id expansion when multi-slot dynamic coverage is satisfied. Augments hazard edge coverage check with additional conditions for dynamic producers with non-submit user edges. Includes helper to detect user edges containing non-submit task-ids.
Mutator state updates and pass construction wiring src/ir/transforms/auto_derive_task_dependencies_pass.cpp	Updates AutoDepMutator member fields to store vector-based task-id mappings, dynamic slot sets, and array extents instead of previous scalar-only var-id mapping. Adjusts pass construction wiring so the mutator receives new collector outputs including task-id vectors for vars and arrays, dynamic slot sets, and extents.
Algorithm documentation updates docs/en/dev/passes/35-auto_derive_task_dependencies.md, docs/zh-cn/dev/passes/35-auto_derive_task_dependencies.md	Updates documentation in both English and Simplified Chinese to clarify step 6 of the AutoDeriveTaskDependencies algorithm: specifies when Array[TASK_ID] dependency values are conservatively expanded (only when lineage is known for direct scalar writes, dynamic loop writes, and per-element array composition), and when arrays with unclear origin remain unexpanded to preserve fallback behavior for missing dependencies.
Test coverage for task-id array dependencies tests/ut/ir/transforms/test_auto_derive_task_dependencies.py	Adds three new unit tests validating that pl.manual_scope() is preserved when loop-propagated task-id information is stored in and accessed from a pl.array of TASK_IDs (covering full indexing, slot-based access, and partial access patterns). Updates one existing test to depend on two separate unrelated task-ids to validate fallback behavior with multiple producers.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~60 minutes

Poem

A rabbit hops through task arrays with glee, 🐰
Tracking TASK_ID lineage, wild and free,
No more false scope demotion's sad refrain,
pl.manual_scope() keeps its parallelism reign,
Array deps resolved—the pass stands in delight! ✨

🚥 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%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: preserving TaskId temporary dependencies in auto-derivation, which directly addresses issue #1744's core problem of manual scopes being incorrectly demoted.
Description check	✅ Passed	The description clearly explains the changes: tracking Array[TASK_ID] lineage, preserving manual scopes for TaskId-array deps, and includes testing performed with concrete examples.
Linked Issues check	✅ Passed	The PR fully addresses issue #1744's objectives: it implements lineage tracking for TaskId arrays, enables correct dependency resolution for arr[i] elements, and preserves user manual scopes by avoiding fallback demotion to AUTO.
Out of Scope Changes check	✅ Passed	All changes are directly related to fixing issue #1744: documentation updates clarify the behavior, core implementation adds TaskId array support, and tests validate the fix with comprehensive coverage of array deps, scalar deps, partial fallback, and unrelated deps scenarios.

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[gemini-code-assist]

Code Review

This pull request enhances the task dependency auto-derivation pass to conservatively expand Array[TASK_ID] dependency values when their lineage is known, updating both documentation and unit tests. The review feedback highlights a critical bug in HasMultiSlotDynamicCoverage where partial slot coverage could incorrectly bypass fallback mechanisms, a potential issue in HasNonSubmitTaskIdUserEdge where unrelated task IDs might satisfy coverage checks, and a recommendation to add a test case verifying fallback behavior for partial slot coverage.

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