[AP] Prepacker Called Twice in AP Flow

[amin1377]

When AP is enabled, molecules are built twice—once at the beginning of global placement when the AP netlist is created, and again at the start of the full legalizer flow. I think the prepacker should ideally be called only once, although for now it’s not time-critical and doesn’t consume much runtime.

[AlexandreSinger]

@amin1377 Thank you so much for flagging this! This is actually a very big issue for the AP flow since we may make references to objects in the prepacker throughout the flow! Luckily, due to the determinism of the prepacker, a Molecule in one prepacker with the same ID will be identical to the other. The prepacker is also never modified in either flow (by design). We were being lucky here. I will look into it sometime next week.