Open YikeZhou opened 2 months ago
Keeping these kinds of unused registers is something that's potentially important for Amaranth and CXXRTL simulations, so I think we need at least a clear way to disable the behavior.
Keeping these kinds of unused registers is something that's potentially important for Amaranth and CXXRTL simulations, so I think we need at least a clear way to disable the behavior.
This was discussed in the context of sby a few years ago and setattr -set keep 1 w:\*
is currently the way to disable that behavior...
Version
Yosys 0.40+25 (git sha1 171577f90, clang++ 14.0.6 -fPIC -Os)
On which OS did this happen?
Linux
Reproduction Steps
Before opening this issue, I found some really useful information in #2165. Though, it was 4 years ago. Therefore, I'm not sure if the following behavior of Yosys is expected but undocumented, or a bug.
Please consider this simple example:
Command:
Expected Behavior
Having read the sections for
opt
andopt_clean
in Yosys manual, I expectedr
to be remained afteropt
was called.Actual Behavior
When running the command above, I noticed that:
It seems that
opt_clean
removedr
and it is missing in the RTLIL output.