Potential bug in stt/flt?

[jkim971201]

If FLUTE_REMOVE_DUPLICATE_PIN is turned on, then the flute code detects if there are duplicate pins here.

However, I think this can only detect a sinlge pair of duplicate pins.
If there are multiple pairs of duplicate pins, then it will fail to remove all the duplicate pairs and produce some bugs in the flute_RDP().
I do not know we have to consider multiple duplicate pin pairs in the OpenROAD flow,
but it will make an error if we use stt/flt as an independent library.
(besides, I think the xs, ys, s vectors should be resized after duplicate removal because flutes() uses the size of the vector as a new net degree.)

Please let me know if I'm misunderstanding.
Thanks.

[maliberty]

Currently we don't use that option (https://github.com/The-OpenROAD-Project/OpenROAD/blob/ead3236e56d57362a8dc8b25658fb41a191eba17/src/stt/include/stt/flute.h#L52) so I don't think it can have any effect on the OR flow. I expect the bug comes from the original flute code that we imported.

If it is important to you then you are welcome to try to fix it and make a PR. However I don't think that will have any direct effect on OR due to our not using this option.