Add pipeline register after LoopMatmul units

[jerryz123]

This seems like it should not break anything or affect performance. This cuts up a critical path

[hngenc]

@jerryz123 Can you make sure this passes the tiled_matmul_ws*.c tests on VCS? (Not just in CI)

[jerryz123]

Sure, I'll check that

[hngenc]

@jerryz123 I think it would be a lot easier to revert all your changes and just add a new queue here instead:

gemmini/src/main/scala/gemmini/Controller.scala

Line 200 in e75b5e9

unrolled_cmd.ready := false.B

It can just be a default queue (pipe doesn't need to be true.B).

That will almost certainly pass CI without any hiccups. (I'm not sure why CI is failing now; your current changes seem benign enough. But my suggestion will be even more benign and easy to implement).

[jerryz123]

This looks good. Do you still want me to check this on manual tests?

[hngenc]

lgtm, thanks. This is a minor enough change that I don't think we need to check this manually