Assuming Cadence Design Systems' attempted takeover of Mentor Graphics takes a conventional turn, we can expect the Mentor management to put a poison pill or two in place (assuming they aren't already in place - it is something I need to check). And there will be some ringing round looking for an alternative bidder, if only to push the price up.
Some around the electronic design automation industry feel that Cadence's manoeuvres are simply a prelude to a big sale to a hardware company, whether a big chipmaker or the foundry TSMC. I find that argument hard to swallow. Chipmakers have some of their own design tools and the ASIC guys made it big by providing tools to their customers. But the people who fab the chips are in no hurry to own generic synthesis, simulation or layout tools. They sold that lot off years ago. They want to be able to plug their own algorithms and point tools into a ready-made chassis. Cadence's OpenAccess gives them that. They don't need to own Cadence.
TSMC is encroaching on the design-for-manufacturing (DFM) with its own software that is meant to be embedded in the software companies' tools. The move has not been popular with the tool providers because they see it as encroachment. However, there isn't a great deal they can do to stop that without effectively forcing TSMC to snap up one of smaller DFM players. It's hard to see TSMC wanting to own a place-and-route tool and effectively alienate most of its own customers: threatening one half with a lock-in and making the other half feel left out in the cold.
The most plausible bidder for a larger EDA company would be one of the mechanical CAD companies, which leads you pretty quickly to the doorstep of Dassault Systèmes and its Enovia Matrix One operation. But which one would Dassault prefer: Cadentor or Mentor on its own, if either of them?
Mentor on its own is probably more attractive than Cadentor because Cadence's target already operates in the automotive market, courtesy of a series of acquisitions, and because the crossover between mechanical and electronic design happens at the level of the PCB, not that of the chip, where Cadence dominates. Dassault would probably have little need for the Calibre operation at Mentor, but could carve it out and sell it for a decent premium to Cadence or Synopsys.
There is a significant counter-argument to the idea of a CAD company buying into EDA. It's been done before, by Intergraph, and the remains of that now sit inside Mentor. Although you would expect there to be a lot of feedback between mechanical and PCB design, in practice there is very little. It is largely because electronic design is so heavily constrained. Other than deciding how high components can stack and what shape the PCB is, there is very little that the mechanical CAD software needs to understand about electronics. That could change in the next five years as cheap alternatives to silicon appear. Plastic electronics will have a much more intimate link to mechanical design. But, there is a question of whether a company such as Dassault would be better off with a traditional PCB company, or a specialist in these new electromechanical technologies – perhaps a MEMS-design company.
Dassault is not the only game in town – there is also Autodesk among others - but the defence company has the most to gain. I only mention Autodesk because there is the potential for irony in such a deal, given that Flomerics, which is on the other end of a hostile bid from Mentor, see Autodesk as its white knight.