UndeclaredReferenceException Error

[mmxsrup]

Hi,

Thank you for developing a very useful tool.
I'm getting an error when generating the Tile.fir graph generated by riscv-mini (https://github.com/ucb-bar/riscv-mini).

The error output is as follows.

[error] (run-main-0) firrtl.passes.PassExceptions: 
[error] firrtl.passes.CheckHighFormLike$UndeclaredReferenceException:  @[Counter.scala 64:20]: [module Cache] Reference _T_115 is not declared.
[error] firrtl.passes.CheckHighFormLike$UndeclaredReferenceException:  @[Counter.scala 64:20]: [module Cache] Reference _T_123 is not declared.
[error] firrtl.passes.CheckHighFormLike$UndeclaredReferenceException:  @[Counter.scala 64:20]: [module Cache_1] Reference _T_115 is not declared.
[error] firrtl.passes.CheckHighFormLike$UndeclaredReferenceException:  @[Counter.scala 64:20]: [module Cache_1] Reference _T_123 is not declared.
[error] firrtl.passes.PassException: 4 errors detected!
[error] firrtl.passes.PassExceptions: 
[error] firrtl.passes.CheckHighFormLike$UndeclaredReferenceException:  @[Counter.scala 64:20]: [module Cache] Reference _T_115 is not declared.
[error] firrtl.passes.CheckHighFormLike$UndeclaredReferenceException:  @[Counter.scala 64:20]: [module Cache] Reference _T_123 is not declared.
[error] firrtl.passes.CheckHighFormLike$UndeclaredReferenceException:  @[Counter.scala 64:20]: [module Cache_1] Reference _T_115 is not declared.
[error] firrtl.passes.CheckHighFormLike$UndeclaredReferenceException:  @[Counter.scala 64:20]: [module Cache_1] Reference _T_123 is not declared.
[error] firrtl.passes.PassException: 4 errors detected!
[error] stack trace is suppressed; run last Compile / bgRunMain for the full output
[error] Nonzero exit code: 1
[error] (Compile / runMain) Nonzero exit code: 1

Regards,
Yuichi