UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

cancel
Showing results for 
Search instead for 
Did you mean: 
Highlighted
Visitor fnc
Visitor
305 Views
Registered: ‎07-22-2019

[Opt 31-131] Removed net

Hi,

I have a custom IP which I'm using in my block design. When I launch the synthesis everything seems to be working as it should, but the implementation always get stuck in "Running route_design". It doesn't throw any errors but it never finishes (I've waited for +9 hours).

While the implementation is being executed, I can access the implementation log, where I found many errors of the type INFO: [Opt 31-131] Removed net: ...

The nets that are being removed are all or nearly all of the nets used in my IP design.

I've checked multiple times my design and my VHDL code and I'm not able to find what is the cause of this issue. Could anyone throw some light on this problem?

 

Thanks in advance.

0 Kudos
7 Replies
Scholar drjohnsmith
Scholar
291 Views
Registered: ‎07-09-2009

Re: [Opt 31-131] Removed net

does the design your routing pass the test bench ?
<== If this was helpful, please feel free to give Kudos, and close if it answers your question ==>
0 Kudos
Visitor fnc
Visitor
279 Views
Registered: ‎07-22-2019

Re: [Opt 31-131] Removed net

Yes, the IP design has been tested sucessfully. There weren't any errors when simulating its behaviour.
0 Kudos
Xilinx Employee
Xilinx Employee
247 Views
Registered: ‎05-22-2018

Re: [Opt 31-131] Removed net

Hi @fnc ,

Please try to apply DONT_TOUCH on your top wrapper in RTL or through XDC and check whether it helpsin completing the implementation. For information on how to use DONT_TOUCH, please check below link page no.49:

https://www.xilinx.com/support/documentation/sw_manuals/xilinx2019_1/ug901-vivado-synthesis.pdf 

Thanks,

Raj

 

0 Kudos
Visitor fnc
Visitor
231 Views
Registered: ‎07-22-2019

Re: [Opt 31-131] Removed net

Hi @rshekhaw,

I've tried before applying DONT_TOUCH directly on the nets that are removed, but nothing changes. Should I apply it in my top module inside the IP?

0 Kudos
Scholar drjohnsmith
Scholar
213 Views
Registered: ‎07-09-2009

Re: [Opt 31-131] Removed net

The point I wante dto highlight was , you are not trying to place yor IP , but a design which also contains your IP.

have you tried to simualte the complete design your getting the errors on , not just the IP ?

 

 

<== If this was helpful, please feel free to give Kudos, and close if it answers your question ==>
0 Kudos
Visitor fnc
Visitor
182 Views
Registered: ‎07-22-2019

Re: [Opt 31-131] Removed net

@drjohnsmithyes, the complete design has been tested. Everything seems to work in the simulation.

0 Kudos
Moderator
Moderator
74 Views
Registered: ‎01-16-2013

Re: [Opt 31-131] Removed net

@fnc 

 

Logic optimization stage removes the loadless cells/nets during sweep stage. Open the synthesized design, search and verify the connection of the net mentioned in INFO message. 

 

Regarding longer runtime during route_design, Can you share the runme.log file present in .runs/impl_1 folder. I believe your design must be congested or have high hold violation which is causing the longer runtime. 

https://www.xilinx.com/support/answers/71571.html 

 

--Syed

---------------------------------------------------------------------------------------------
Kindly note- Please mark the Answer as "Accept as solution" if information provided is helpful.
Give Kudos to a post which you think is helpful and reply oriented.

Did you check our new quick reference timing closure guide (UG1292)?
---------------------------------------------------------------------------------------------
0 Kudos