Optimization of Pins Partially Outside the PR Boundary

Pin Optimizer supports optimization of pins in instances that are partially outside the top-level PR boundary. Set the optimizeInstancesPartiallyOutsidePRB environment variable to t to enable optimization of such pins. Consider the following placement of instances:

The following table explains the behavior when optimizeInstancesPartiallyOutsidePRB is set to nil (default) and t, respectively:

Blocks 4, 5, and 7 are partially outside the PR boundary. Therefore pins in these blocks are optimized when optimizeInstancesPartiallyOutsidePRB is set to t.

However all vertices of Block 3 are outside the PR boundary, while block 6 is completely outside the PR boundary. So pins in these blocks are not optimized even when optimizeInstancesPartiallyOutsidePRB is set to t.

To consider an instance to be partially inside or outside the PR boundary, at least one of its corner (vertex) should lie inside the PR boundary.

Virtuoso Floorplanner User Guide
Product Version IC23.1, November 2023