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…epair OpenROAD (new pin from #71, tested at 5f1bd87f) crashes deterministically in cts.tcl's post-CTS repair_timing on this netlist: [ERROR ODB-1200] InsertBufferBeforeLoads: Load pin '_34829_/SN' is not connected to net '_03825_'. Error: cts.tcl, 82 ODB-1200 The new RSZ-0100 move sequence puts UnbufferMove first; an unbuffer step orphans a load pin before a subsequent InsertBufferBeforeLoads pass tries to reference it, tripping an ODB consistency check at iter ~141 of a 347-endpoint hold-violation sweep. The worst-slack endpoint (the reset synchronizer's D pin) is only a spurious display artifact — the churn is on the datapath hold-violations, not reset. Workarounds attempted and ruled out: - set_dont_touch on reset net pattern: doesn't shrink the STA endpoint set, and Yosys flat-synth renames the net anyway. No-op. - set_false_path -from sys_reset + -through reset net candidates: RSZ-0046 dropped 347 -> 346 (one endpoint removed), confirming the 346 others aren't on the reset cone. Same crash. Only SKIP_CTS_REPAIR_TIMING=1 bypasses the bug. Downstream GRT and route still run their own hold-repair passes, so final QoR remains reasonable (41% util, 14886 um^2 on asap7, clean 6_final). Also keep a principled set_false_path -from sys_reset in the SDC (sys_reset is an async input synchronized internally by udpcore_int_rst; the port-to-synchronizer path shouldn't be timed). Tracking re-enable: #75
This was referenced Apr 30, 2026
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Summary
SKIP_CTS_REPAIR_TIMING=1ondesigns/asap7/liteeth/liteeth_udp_stream_sgmiito bypass a deterministic OpenROAD crash in post-CTS hold-repair (tested at OR commit5f1bd87f, bazel-orfs pin from Bazel flow: source-built OpenROAD via pinned bazel-orfs submodule #71).set_false_path -from [get_ports sys_reset]to the SDC (async reset input synchronized internally; port-to-synchronizer path shouldn't be timed).The bug
The new RSZ-0100 move sequence (UnbufferMove first) orphans a load pin, then a later
InsertBufferBeforeLoadspass trips an ODB consistency check. Fires at iter ~141 of a 347-endpoint hold-violation sweep. Bit-for-bit reproducible across runs.Workarounds I tried and ruled out (see #75 and commit message for details):
set_dont_touchon reset net pattern — no-op (name didn't survive Yosys flat-synth).set_false_pathon reset cone —RSZ-0046dropped only 347 → 346; the 346 other violations are datapath, not reset.SKIP_CTS_REPAIR_TIMING=1is the only thing that works. Downstream GRT and route still run their own hold-repair passes.Test plan
./k8s/run.sh --branch liteeth --upload-artifacts asap7 liteeth_udp_stream_sgmii— full k8s flow now completes end-to-end (41% util, 14886 µm², clean6_final.gdson asap7).