Multi-cgra mapper integration

[guosran]

Summary

This PR addresses issue #275. It adds multi-CGRA task placement support to MapTaskOnCgraPass and integrates it into ResourceAwareTaskOptimizationPass.

Changes

MapTaskOnCgraPass

• Multi-CGRA placement in findBestPlacement: Tasks with cgra_count > 1 are now placed using a cascading shape search:

  1. Try all rectangular shapes of the requested cgra_count (e.g., 1×3, 3×1 for cgra_count=3).
  2. If no rectangular shape fits, try all connected non-rectangular shapes (L-shapes, T-shapes, etc.) via DFS enumeration.
  3. If nothing fits, fall back to cgra_count - 1 (reject the extra CGRA, keep the previous allocation).

• parseTileShapeOffsets: Parses the tile_shape attribute string (e.g., "2x2", "2x2[(0,0)(1,0)(0,1)]") into physical CGRA offset coordinates. Added assertion for empty offsets.

• computeScore: Updated to handle multi-CGRA placements by computing the minimum Manhattan distance from any CGRA in the placement to the target, reflecting fast bypass paths between adjacent CGRAs.

• Helper functions: Extracted tryPlaceShape, getRectShapes, and tryNonRectShapes for clarity and reuse.

• Public API: Exposed runMapTaskOnCgra(FuncOp, int, int) in TaskflowPasses.h so other passes can invoke placement directly.

ResourceAwareTaskOptimizationPass

• Integration: After the balance/fusion convergence loop, calls runMapTaskOnCgra() to produce task_mapping_info attributes with global grid placement that respects multi-CGRA shapes.

[Copilot]

Pull request overview

This PR adds multi-CGRA task placement support to MapTaskOnCgraPass and integrates global placement generation (task_mapping_info) into ResourceAwareTaskOptimizationPass after the balance/fusion loop converges (issue #275).

Changes:

• Extend CGRA placement to support tasks spanning multiple CGRAs (rectangular and connected non-rectangular shapes), and update scoring to account for multi-tile proximity.
• Expose runMapTaskOnCgra(func, rows, cols) as a callable helper and invoke it from ResourceAwareTaskOptimizationPass post-convergence.
• Update multi-CGRA MLIR tests to reflect new RESOPT output formatting and/or placement results.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
lib/TaskflowDialect/Transforms/MapTaskOnCgraPass.cpp	Implements multi-CGRA placement search + scoring changes; adds runMapTaskOnCgra entrypoint.
lib/TaskflowDialect/Transforms/Optimizations/ResourceAwareTaskOptimizationPass.cpp	Calls runMapTaskOnCgra after convergence to materialize task_mapping_info.
include/TaskflowDialect/TaskflowPasses.h	Exposes runMapTaskOnCgra in the public header.
test/multi-cgra/taskflow/resource-heavy/resource-heavy.mlir	Adjusts RESOPT FileCheck expectations (line-wrapped attrs).
test/multi-cgra/taskflow/resnet/simple_resnet_tosa.mlir	Adjusts RESOPT FileCheck expectations (line-wrapped attrs).
test/multi-cgra/taskflow/parallel-nested/parallel-nested.mlir	Adjusts RESOPT FileCheck expectations (line-wrapped attrs).
test/multi-cgra/taskflow/multi-nested/multi-nested.mlir	Updates placement expectations and RESOPT FileCheck formatting.
test/multi-cgra/taskflow/irregular-loop/irregular-loop.mlir	Adjusts RESOPT FileCheck expectations (line-wrapped attrs).

Comments suppressed due to low confidence (1)

lib/TaskflowDialect/Transforms/MapTaskOnCgraPass.cpp:294

• If findBestPlacement() returns an empty placement (including after the fallback), the code still commits placement.primary() which becomes (-1,-1). That invalid coordinate then propagates into task_mapping_info and into SRAM centroid computation (assignAllSRAMs sums all positions), producing incorrect placements instead of failing loudly. Handle the "no placement found" case explicitly (e.g., emit an MLIR diagnostic and signalPassFailure / return failure), and avoid pushing a sentinel position into task_node->placement.

          // Commits Placement.
          task_node->placement.push_back(placement.primary());
          for (size_t i = 1; i < placement.cgra_positions.size(); ++i) {
             task_node->placement.push_back(placement.cgra_positions[i]);
          }

          // Marks occupied.
          for (const auto &pos : placement.cgra_positions) {
            if (pos.row >= 0 && pos.row < grid_rows_ && pos.col >= 0 && pos.col < grid_cols_) {
                occupied_[pos.row][pos.col] = true;
            }
          }

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[tancheng]

CGRAPosition -> CgraPosition

[guosran]

Renamed

[tancheng]

Can we rename this to AllocateCgraToTaskPass? I feel mapping is more concrete, but allocation is about rough resource allocation. WDYT @ShangkunLi?

[ShangkunLi]

Agree. For the current map-to-accelerator pass, can we rename it to MapOperationOnTilePass, as mentioned in #274.

[guosran]

Renamed the two passes accordingly.