Disable OPT-1206 and OPT-1207 in Design Compiler

[PityOnU]

I am having issues pushing a rather large design of mine through Design Compiler. It keeps OPT-1206 and OPT-1207'ing away all of my registers ("------ is a constant and will be removed.")

I have tried the following commands:

set_dont_touch <entity name>
set compile_delete_unloaded_sequential_cells false
set hdlin_preserve_sequential true

But still the thing is wiping out a ton of my gates and making the design not work correctly in simulation. Does anyone know how I would disable all of these optimizations?

 

[sameer_dlh25]

I think look for

1. Check if compile_delete_unloaded_sequential_cells variable value.
2. set_dont_touch is applied properly.

Let me know if this helps

Cheers
Sameer

 

[PityOnU]

I think look for

1. Check if compile_delete_unloaded_sequential_cells variable value.
2. set_dont_touch is applied properly.

Let me know if this helps

Cheers
Sameer

Hi Sameer,

Thanks for the pointers. After messing with set_dont_touch some more, I managed to get it to no longer remove any of my flip-flops.

However, the compiler is still removing some constants I have in my design - which is a problem because I set them as constants for a reason! I'm going to try to play with the compile_seqmap_propogate_constants switch some here, but if anyone knows off the top of their head a better way to do it, any and all help you could offer is much appreciated!

Thanks again!

~ Kent