Summary
On the 2026-06 upgrade, vortex-sky130hd reaches 6_final but: WNS +130 → −173 ps (SRAM-bound path, same shape as asap7) and logic cells 94 627 → 121 621 (+28.5 %).
Root cause
Same yosys-0.64 FF-memory read-mux lowering as vortex-nangate45 (depth-16 reg-array MUX2 trees) for the area growth; the negative WNS is the SRAM-read-bound path. ABC_AREA=1 reverted (made cells 159 164).
Scope
Reaches 6_final; flagged on both setup and area. Neither recoverable via flow knobs without RTL/SDC. See designs/src/vortex/DECISIONS.md (sky130hd). Related: vortex-nangate45 (area), vortex-asap7 (SRAM path). Part of PR #195.
Summary
On the 2026-06 upgrade, vortex-sky130hd reaches
6_finalbut: WNS +130 → −173 ps (SRAM-bound path, same shape as asap7) and logic cells 94 627 → 121 621 (+28.5 %).Root cause
Same yosys-0.64 FF-memory read-mux lowering as vortex-nangate45 (depth-16 reg-array MUX2 trees) for the area growth; the negative WNS is the SRAM-read-bound path.
ABC_AREA=1reverted (made cells 159 164).Scope
Reaches
6_final; flagged on both setup and area. Neither recoverable via flow knobs without RTL/SDC. Seedesigns/src/vortex/DECISIONS.md(sky130hd). Related: vortex-nangate45 (area), vortex-asap7 (SRAM path). Part of PR #195.