[AP] Using Pin Offsets During Global Placement

[AlexandreSinger]

Currently, the AP flow treats all blocks as points of zero area. This is ok, but not ideal. Atom blocks have input and output pins which are usually offset from one another (for example, the input may be 1 tile to the left of the output).

Fixed points are the biggest issue. Currently, we just put fixed points at the center of the tile they are located in. However, since they are fixed, we may know exactly which side of the tile the fixed pin may be.

Another example is carry-chains which have many atoms attached together.

Global Placement should somehow take these pin offsets into account.

See the following for context:
#2990 (comment)