Allow multi-source packet flows; fix pathfinder silent drop#2963
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Allow multi-source packet flows; fix pathfinder silent drop#2963
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PacketFlowOp::verify() was rejecting flows with more than one aie.packet_source, breaking valid fan-in topologies that predate the verifier check added in PR #2919. Relax the check from `numSources != 1` to `numSources < 1` so zero-source flows are still rejected while multi-source flows are accepted. The pathfinder (AIEPathFinder.cpp / AIECreatePathFindFlows.cpp) had a related "last source wins" bug: Pass 1 overwrote the single srcCoords/ srcPort accumulator on each PacketSourceOp, silently dropping all but the last source before calling addFlow(). This is left for a follow-up fix; the per-source loop change belongs in a separate commit. Tests added / updated: - badpacket_flow_source_count.mlir: remove multi-source rejection case (no longer an error), update error message for zero-source case - multi_source_packet_flow.mlir: positive verifier regression test - multi_source_pathfinder.mlir: pathfinder-level regression test (currently failing — documents the remaining bug) - npu-xrt/multi_source_packet_flow/: end-to-end hardware test Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Pass 1 of the packet-flow lowering in AIEPathFinder.cpp and AIECreatePathFindFlows.cpp accumulated a single srcCoords / srcPort, overwriting it on every PacketSourceOp it encountered. For multi-source (fan-in) packet flows that meant only the last source ever reached addFlow / the switchbox-connection loop -- earlier sources were silently dropped from the routing. Collect all sources into a vector and iterate (source, dest) pairs in Pass 2 so each source contributes a Flow / switchbox connection. Pathfinder::addFlow already groups same-dest fan-ins by packetGroupId, so calling it once per source is the intended shape. Drops the pre-existing "// todo: support many-to-one & many-to-many?" note now that many-to-one works. Single-source flows are unchanged (the sources vector just holds one entry). Co-Authored-By: Claude Opus 4 (1M context) <noreply@anthropic.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
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PacketFlowOp::verify() was rejecting flows with more than one aie.packet_source, breaking valid fan-in topologies that predate the verifier check added in PR #2919. Relax the check from
numSources != 1tonumSources < 1so zero-source flows are still rejected while multi-source flows are accepted.The pathfinder (AIEPathFinder.cpp / AIECreatePathFindFlows.cpp) had a related "last source wins" bug: Pass 1 overwrote the single srcCoords/ srcPort accumulator on each PacketSourceOp, silently dropping all but the last source before calling addFlow(). This is left for a follow-up fix; the per-source loop change belongs in a separate commit.
Tests added / updated: