Generating SRAM fails at `supply_router`: Couldn't route from (vdd layer=m3 ...) to to (vdd layer=m3 ...)

[kammoh]

Describe the bug

Generating an SRAM using sky130 with the following config:

num_words = 256
word_size = 96
write_size = 96
num_rw_ports = 2

After running for about ~30 minutes, I get this error:

ERROR: file supply_router.py: line 84: Couldn't route from (vdd layer=m3 ll=v[214.355,-55.435] ur=v[214.845,-54.945]) to (vdd layer=m3 ll=v[214.995,-44.165] ur=v[215.485,-43.675])

Same issue with:

num_rw_ports = 1
num_r_ports = 1

Same issue using different Python versions.

Version
Version 1.2.48 (stable branch commit b6a6f12)

To Reproduce
Please see above.

Expected behavior
SRAM generated?

Logs
For 1rw1r config:

[2025-05-13 20:14:47.056401] RW ports: 1
R-only ports: 1
W-only ports: 0
[2025-05-13 20:14:47.056482] DRC/LVS/PEX is only run on the top-level design to save run-time (inline_lvsdrc=True to do inline checking).
[2025-05-13 20:14:47.056561] Characterization is disabled (using analytical delay models) (analytical_delay=False to simulate).
[2025-05-13 20:14:47.056642] Only generating nominal corner timing.
[2025-05-13 20:14:47.056724] Words per row: None
[2025-05-13 20:14:47.056815] Output files are: 
...
[2025-05-13 20:14:56.045561] ** Submodules: 8.9 seconds
[2025-05-13 20:14:56.183615] ** Placement: 0.1 seconds
[2025-05-13 20:46:04.762107] ERROR: file supply_router.py: line 84: Couldn't route from (vdd layer=m3 ll=v[214.355,-55.435] ur=v[214.845,-54.945]) to (vdd layer=m3 ll=v[214.995,-44.165] ur=v[215.485,-43.675]).

Additional context
Add any other context about the problem here.

[mguthaus]

It's an odd, and very large, word size. I'd consider banking or other optimization.

Often this type of thing is just caused by a pin access problem, but you would need to identify it in the temp output that is saved. The top of the run should tell you what the GDS file name is to investigate.

Sorry, but we don't have resources to fix bugs, but would welcome any improvements as a PR>