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5c8ecd2a46
This PR adds a new optimizer step:
5568270f77/autoprecompiles/src/constraint_optimizer.rs (L96-L108)
This can be useful to remove "left-over" range constraints, e.g. from
removed memory bus interactions:
- Imagine a memory bus interaction receiving a previous time stamp and
then having a range constraint like `[current_timestamp - prev_timestamp
- 1] in [BIT16]` to enforce that it is smaller than the current
timestamp.
- Then, `prev_timestamp` would only be mentioned in this stateless bus
interaction after the memory bus interaction is removed by the memory
optimizer.
- The `remove_disconnected_columns` step would not remove it, because
`current_timestamp` is also mentioned and it is connected to a stateful
bus interaction.
- The constraint is still redundant: For any value of
`current_timestamp`, the prover could pick a satisfying value for
`current_timestamp - prev_timestamp - 1` (e.g. $0$) and solve for
`prev_timestamp`
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Co-authored-by: Thibaut Schaeffer <schaeffer.thibaut@gmail.com>