[LoopScheduleToCalyx] deduplicate groups within a ParOp.

[cgyurgyik]

Deduplicates multiple occurrences of the same Enable in a ParOp. This can be introduced automatically by a compiler lowering phase, so we add this as a canonicalization pattern. Additionally, ensures that the pipeline register (and not the pipeline stage) is used in Calyx computation assignments.

Fixes #8050.

[mikeurbach]

I think this makes sense as a canonicalization, but is the error avoided with the change in LoopScheduleToCalyx? In general, I think we strive for a world where the canonicalizations are not required for success / correctness.

[cgyurgyik]

I think this makes sense as a canonicalization, but is the error avoided with the change in LoopScheduleToCalyx? In general, I think we strive for a world where the canonicalizations are not required for success / correctness.

It is not, that change avoids a use after free issue. I have not totally fixed the error yet though so going back to draft mode.

(Edit: I agree with your sentiment. I'll follow up later)

[cgyurgyik]

@mikeurbach I've updated this so that canonicalization isn't used as an "operation fixer-upper".

[mikeurbach]

awesome, thanks for that. looks good to me.

[cgyurgyik]

Thanks! This is branched off #8048 so if you have a chance to review that, it'd be great :-)