✨ Record typed compiler targets in MQT IR

[burgholzer]

🤖 AI text below 🤖

Description

This PR adds #mqt.compilation_target and its typed leaf attributes to the MQT dialect. CompilerTarget can materialize its immutable source facts as the attribute and reconstruct a validated C++ target from it. The round trip preserves target and site names, ordered sparse site IDs, timing metadata, connectivity, native operations, placements, durations, fidelities, and fixed or variadic operation arities. Fixed arities include zero-arity operations such as gphase; variadic arities record a positive inclusive minimum for arbitrarily controlled native operations.

This is the focused typed-serialization layer at the top of the stack. It builds on #2323, which builds on the compiler target introduced by #2218. It deliberately excludes payload descriptors, execution capabilities, combined target environments, module attachment, and DLTI integration. Those contracts remain separate work.

The TableGen definitions provide concrete syntax examples in the generated dialect documentation, including a complete #mqt.compilation_target example. Attribute verifiers reject malformed target facts before reconstruction, while the existing C++ factories remain the single source of truth for target validation and derived caches.

The changelog records this PR in the existing MQT Compiler Collection launch entry rather than adding a separate entry for unreleased functionality. Its PR-link definition remains in numeric descending order.

Validation

• Rebased as one signed commit on ✨ Preserve target-native controlled operations #2323 at 60d5bb4db2a4672214ea793dbfe6e2d6c92c8863.
• MQT dialect unit tests: 14 passed.
• Compiler unit tests: 146 passed.
• cmake --build --preset release --target mlir-doc
• uvx nox -s lint
• uvx nox -s cpp-lint
• git diff --check
• git verify-commit HEAD

Implementation and pull-request text were prepared with OpenAI Codex.

Checklist

• The pull request only contains commits that are focused and relevant to this change.
• I have added appropriate tests that cover the new/changed functionality.
• I have updated the documentation to reflect these changes.
• I have added entries to the changelog for any noteworthy additions, changes, fixes, or removals.
• I have added migration instructions to the upgrade guide (if needed).
• The changes follow the project guidelines and introduce no new warnings.
• The changes are fully tested and pass the CI checks.
• I have reviewed my own code changes.

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[codecov]

Codecov Report

❌ Patch coverage is 92.98893% with 19 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
mlir/lib/Compiler/Target.cpp	91.9%	10 Missing ⚠️
mlir/lib/Dialect/MQT/IR/MQTDialect.cpp	94.6%	7 Missing ⚠️
mlir/include/mlir/Dialect/MQT/IR/MQTAttributes.h	86.6%	2 Missing ⚠️

📢 Thoughts on this report? Let us know!

[burgholzer]

This also looks genuinely good except for one little detail.

[coderabbitai]

Important

Approval pending

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[denialhaag]

I really like the addition of these attribues! I only have a nitpick and a comment on the attribute descriptions, otherwise this LGTM! I'm already approving now, as neither of my comments is blocking. 😎

[burgholzer]

This was essentially just updated based on the changes in the stack below it. Might not hurt to give it a sanity check though.

[denialhaag]

This LGTM!

I just have two nitpicks, both of which are not blocking:

[simon1hofmann]

This one also looks good, just one thing to clarify.

[simon1hofmann]

@burgholzer This one is ready to be merged as well right?

[burgholzer]

@burgholzer This one is ready to be merged as well right?

Yes, let's get this is once CI is green 🚀
That should also conclude the 4.0 split of this stack.
We may actually want to split off the rest from that stack and form a new one after reorganizing. I'll keep that in mind for after this merges.