How to find connections to a net?

I don't know of a Tcl command, although I'm sure it's possible to make your own, since there are commands for getting full path information. I'm sure you just want your own, though.

I generally locate a node to the Chip Planner. I make sure the equation viewer is on. With the node highlighted I see all of it's fan-in and fan-out, and can select nodes in those boxes and click on the Go To button to select them. I also use the Show Fan-Out or Show Fan-In boxes to visually see them all.

For example, I may start at a source register and click Show Fanout. Then in the equation viewer I will highlight all the combinatorial nodes(they have a c by them) and click on Go To. I then click on Show Fanout again, and proceed.

Note that the end result is almost identical to just doing a "report_timing -from source_node", then highlighting all the paths in the Summary and right-click Locate to Chip Planner. The problem is that this is often a rats-nest, where my method lets me see them grow step-by-step. I usually don't even trace the whole path, I just get an idea of how that register's fanouts grow, which is what I'm looking for.

Also note that a Tcl dump will often make it look like there are more nodes than you think. A path into a memory or DSP may look like a single physical node, but a Tcl dump would show that it feeds many different registers within that block. Technically, I prefer to still think of it as one location though.

Another thing I run to analyze how thick logic is, is to run timing analysis from a source(or to a destination), once with -pairs_only and once without, to get a better idea of how many rats nest are between endpoints. If you try it you'll see what I mean. I have a design I'm looking at right now that only shows 20 paths coming from a source when I do -pairs_only, and over 20,000 paths when I don't.