runtimeverification / runtimeverification/mir-semantics
(How to) Determine bit width and signedness for `Int` values from `Discriminant`
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- Dominant language
- Python
- Stars
- 52
- Forks
- 5
- PR merge metrics
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Description
#792 sets bitwidth of Discriminant values to 0 as a sentinel and relaxes type constraints for comparison and SwitchInt.
If possible, we want to instead use the correct bit width and signedness for discriminants but it is unclear whether and how they can be obtained from the layout (it is not the tag encoding alone, or else the MIR tolerates type mismatches for assignments).
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reading issue #792 and tracing how Discriminant values are represented for comparisons, SwitchInt, and assignments. Investigate whether the layout provides the correct bit width and signedness beyond the tag encoding; done means replacing the zero-bit sentinel if those properties can be determined reliably.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python, rust
- Domain
- compilers
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100