🐛 Fix equivalence checking of LLVM::CallOps

[denialhaag]

Description

This PR fixes the equivalence checking of LLVM::CallOps.

Without this change, the following test passes:

TEST_F(CompilerPipelineTest, CX) {
  ::qc::QuantumComputation comp;
  comp.addQubitRegister(2, "q");
  comp.cx(0, 1);

  const auto module = importQuantumCircuit(comp);
  ASSERT_TRUE(module);
  ASSERT_TRUE(runPipeline(module.get()).succeeded());

  const auto qc = buildQCIR([](mlir::qc::QCProgramBuilder& b) {
    auto reg = b.allocQubitRegister(2, "q");
    b.cx(reg[0], reg[1]);
  });
  const auto qco = buildQCOIR([](qco::QCOProgramBuilder& b) {
    auto reg = b.allocQubitRegister(2, "q");
    b.cx(reg[0], reg[1]);
  });
  const auto qir = buildQIR([](qir::QIRProgramBuilder& b) {
    auto reg = b.allocQubitRegister(2);
    b.cy(reg[0], reg[1]); // ERROR: Must be cx instead of cy
  });

  verifyAllStages({
      .qcImport = qc.get(),
      .qcoConversion = qco.get(),
      .optimization = qco.get(),
      .qcConversion = qc.get(),
      .qirConversion = qir.get(),
  });
}

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's style guidelines and introduce no new warnings.
• The changes are fully tested and pass the CI checks.
• I have reviewed my own code changes.

[coderabbitai]

📝 Walkthrough

Summary by CodeRabbit

• Tests

  • Improved equivalence checks in compiler validation to more accurately detect differences in call operations, enhancing test reliability.

• Documentation

  • Updated changelog to reference additional related PRs for the new dialect infrastructure.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

Walkthrough

Adds a structural equivalence check for LLVM::CallOp in the operation comparison: when the left-hand operation is a CallOp, the right-hand must also be a CallOp with an identical callee. Also updates CHANGELOG.md PR link entries.

Changes

Cohort / File(s)	Summary
LLVM CallOp Equivalence Check mlir/unittests/Compiler/test_compiler_pipeline.cpp	Added logic to require matching callee identity when comparing LLVM::CallOp operations; complements existing constant/operand/result checks.
Changelog updates CHANGELOG.md	Extended "Added" entry to reference additional PRs and added corresponding PR links in the changelog.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Suggested reviewers

• burgholzer

Poem

🐰 I hopped through code to make a call,
Left and right must mirror all,
Callees matched in neat array,
Tests now check them true as day,
Hooray, the pipeline bounces well!

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Description check	❓ Inconclusive	The description includes a summary of the fix and demonstrates the problem with a concrete test case, but the checklist shows incomplete documentation and test additions.	Clarify why test additions and documentation updates were not needed, or complete them if they should have been included per the template requirements.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: fixing equivalence checking for LLVM::CallOp operations.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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