## Steps to reproduce the issue

*Provide instructions for reproducing the issue. Make sure to include
all necessary source files. (You can simply drag&drop a .zip file into
the issue editor.)*

Also, make sure that the issue is actually reproducable in current git
master of Yosys.

See https://stackoverflow.com/help/mcve for some information on how to
create a Minimal, Complete, and Verifiable example (MCVE).

Please do not waste our time with issues that lack sufficient information
to reproduce the issue easily. We will simply close those issues.

Contact https://www.yosyshq.com/ if you need commercial support for Yosys.

## Expected behavior

*Please describe the behavior you would have expected from the tool.*

## Actual behavior

*Please describe how the behavior you see differs from the expected behavior.*
