Operator swapping at 3_4 leads to a placement check failure at 3_5

[povik]

Subject

[Stage]: Global Placement.

Describe the bug

In resize.tcl we invoke replace_arith_modules on designs with SWAP_ARITH_OPERATORS=1.

If an operator gets swapped at this stage, it appears to introduce unplaced instances which leads to a placement check failure at stage 3_5 (detail_place.tcl). Excerpts of logs are below.

3_4 resize.tcl

[2026-01-28T13:54:41.174Z] [INFO RSZ-0151] Starting arithmetic module replacement to optimize 'setup' target
[2026-01-28T13:54:41.174Z] [INFO RSZ-0152] Analyzing 1000 critical paths with slack < 0.00
[2026-01-28T13:54:42.756Z] [INFO RSZ-0153] Identified 943 violating endpoints
[2026-01-28T13:54:42.756Z] [INFO RSZ-0154] Identified 2 critical arithmetic instances
[2026-01-28T13:54:42.756Z] [WARNING ODB-0453] The modules cannot be swapped because module ALU_32_0_32_0_32_unused_CO_X_HAN_CARLSON has 114 ports but module ALU_32_0_32_0_32_unused_CO_X_KOGGE_STONE has 101 ports.
[2026-01-28T13:54:42.756Z] [INFO RSZ-0160] 1 arithmetic instances have swapped to improve 'setup' target

3_5 detail_place.tcl

[2026-01-28T13:55:40.136Z] Detailed Improvement Results
[2026-01-28T13:55:40.136Z] ------------------------------------------
[2026-01-28T13:55:40.136Z] Original HPWL          3087073.1 u ( 1585684.0,  1501389.1)
[2026-01-28T13:55:40.136Z] Final HPWL             3013615.9 u ( 1539112.0,  1474503.9)
[2026-01-28T13:55:40.136Z] Delta HPWL                  -2.4 % (      -2.9,       -1.8)
[2026-01-28T13:55:40.136Z] 
[2026-01-28T13:55:40.136Z] [INFO DPL-0020] Mirrored 4923 instances
[2026-01-28T13:55:40.136Z] [INFO DPL-0021] HPWL before          3013615.9 u
[2026-01-28T13:55:40.136Z] [INFO DPL-0022] HPWL after           3013064.9 u
[2026-01-28T13:55:40.136Z] [INFO DPL-0023] HPWL delta               -0.0 %
[2026-01-28T13:55:40.495Z] [WARNING DPL-0003] Placed check failed (292).
[2026-01-28T13:55:40.495Z]  swerv.exu.i0_alu_e4.aout$\\swerv.exu.i0_alu_e4.cout\\ALU_32_0_32_0_33_unused_CO_X_HAN_CARLSON/_292_
[2026-01-28T13:55:40.495Z]  swerv.exu.i0_alu_e4.aout$\\swerv.exu.i0_alu_e4.cout\\ALU_32_0_32_0_33_unused_CO_X_HAN_CARLSON/_293_
[2026-01-28T13:55:40.495Z]  swerv.exu.i0_alu_e4.aout$\\swerv.exu.i0_alu_e4.cout\\ALU_32_0_32_0_33_unused_CO_X_HAN_CARLSON/_294_
[2026-01-28T13:55:40.495Z]  swerv.exu.i0_alu_e4.aout$\\swerv.exu.i0_alu_e4.cout\\ALU_32_0_32_0_33_unused_CO_X_HAN_CARLSON/_295_
[2026-01-28T13:55:40.495Z]  swerv.exu.i0_alu_e4.aout$\\swerv.exu.i0_alu_e4.cout\\ALU_32_0_32_0_33_unused_CO_X_HAN_CARLSON/_296_
[2026-01-28T13:55:40.495Z]  swerv.exu.i0_alu_e4.aout$\\swerv.exu.i0_alu_e4.cout\\ALU_32_0_32_0_33_unused_CO_X_HAN_CARLSON/_297_
[2026-01-28T13:55:40.495Z]  swerv.exu.i0_alu_e4.aout$\\swerv.exu.i0_alu_e4.cout\\ALU_32_0_32_0_33_unused_CO_X_HAN_CARLSON/_298_
[2026-01-28T13:55:40.495Z]  swerv.exu.i0_alu_e4.aout$\\swerv.exu.i0_alu_e4.cout\\ALU_32_0_32_0_33_unused_CO_X_HAN_CARLSON/_299_
[2026-01-28T13:55:40.495Z]  swerv.exu.i0_alu_e4.aout$\\swerv.exu.i0_alu_e4.cout\\ALU_32_0_32_0_33_unused_CO_X_HAN_CARLSON/_300_

...

...
[2026-01-28T13:55:40.495Z] [ERROR DPL-0033] detailed placement checks failed.
[2026-01-28T13:55:40.495Z] write_db ./results/nangate45/swerv_wrapper/base/3_5_place_dp-failed.odb
[2026-01-28T13:55:40.495Z] Error: detail_place.tcl, 37 DPL-0033
[2026-01-28T13:55:40.495Z] Command exited with non-zero status 1

Expected Behavior

No flow errors from operator swap

Environment

.

To Reproduce

It occurred in this CI run

https://jenkins.openroad.tools/blue/organizations/jenkins/OpenROAD-flow-scripts-Private/detail/secure-mpl-improve-notches/11/pipeline/234/

Relevant log output

Screenshots

No response

Additional Context

No response

[povik]

@precisionmoon @maliberty I think we need to remove replace_arith_modules from resize.tcl until we figure out placement for swapped operators. We'll still have the other invocation in floorplan.tcl.

[precisionmoon]

Thanks for bringing this up. Perhaps we need to add incremental global placer in resize.tcl.