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REMOVE_ABC_BUFFERS=1 dates from August 2024, when floorplan.tcl first kept the ABC buffers and ran a full repair_timing, which some designs could not finish. The floorplan repair is now a cheap unbuffer/sizeup/swap/vt_swap pass without last gasp. sky130hd/aes, sky130hd/jpeg and sky130hs/aes pass the QoR dashboard check without the flag, so they drop it. The remaining designs regress without it (ihp-sg13g2/aes, sky130hd and sky130hs riscv32i, ihp-sg13g2/jpeg) or could not be checked (ibex uses slang, gf12 is private), so the variable stays. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>
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This pull request removes the deprecated REMOVE_ABC_BUFFERS variable from several design configurations and updates its documentation to note that disabling it may impact the Quality of Results (QoR). The review feedback recommends clarifying the phrasing of this documentation update across FlowVariables.md, variables.json, and variables.yaml to state more professionally that some designs may experience degraded QoR without it.
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🔍 QoR checkMetrics reflect the PR merge build — i.e. what will land on the target branch. Commit 62 design(s) checked — 0 with regression(s), 0 without a comparable baseline. |
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>
This was referenced Sep 29, 2026
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floorplan.tcl now always runs repair_timing_helper. The variable is dropped from variables.yaml, variables.json and FlowVariables.md. Designs are deliberately not touched here; they are handled by The-OpenROAD-Project#4575, The-OpenROAD-Project#4576, The-OpenROAD-Project#4577, The-OpenROAD-Project#4578 and The-OpenROAD-Project#4579. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>
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TL;DR whittle down REMOVE_ABC_BUFFERS usage.
Why the flag exists
remove_buffersunconditionally. It kept the ABC buffers and ran a fullrepair_timing.REMOVE_ABC_BUFFERS=1was added to get the old behaviour back.repair_timing_helper -setup -skip_last_gasp -sequence "unbuffer,sizeup,swap,vt_swap", with no clone/split and no last gasp. So the original reason may no longer hold. This PR checks each public design that still sets the flag.Method
make finish metadata-generatetwice, from the same tools:config.mkas-is.REMOVE_ABC_BUFFERS=0on the command line.checkQorMetrics.pyagainst the dashboard'sbasemaster baseline.bazelisk run //:install(bazel: //:install also installs yosys for ORFS OpenROAD#11563). Runs went 4 at a time withNUM_CORES=4, so the times are only indicative.DRT completed in every run. The flag is no longer needed to get through routing, but some designs still depend on it for QoR.
Not checked here
SYNTH_HDL_FRONTEND=slang, which the Bazel-installed yosys doesn't have yet.These keep the flag, and the variable stays as deprecated. Its description now says that the designs still setting it lose QoR without it.
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