✨ Canonicalize equivalent qc.static operations

CHANGELOG.md

@@ -15,7 +15,7 @@ This project adheres to [Semantic Versioning], with the exception that minor rel
 - ✨ Add conversions between Jeff and QCO ([#1479], [#1548], [#1565]) ([**@denialhaag**])
 - ✨ Add a `place-and-route` pass for mapping circuits to architectures with restricted topologies ([#1537], [#1547], [#1568], [#1581], [#1583], [#1588]) ([**@MatthiasReumann**])
 - ✨ Add initial infrastructure for new QC and QCO MLIR dialects
-  ([#1264], [#1330], [#1402], [#1428], [#1430], [#1436], [#1443], [#1446], [#1464], [#1465], [#1470], [#1471], [#1472], [#1474], [#1475], [#1506], [#1510], [#1513], [#1521], [#1542], [#1548], [#1550], [#1554], [#1569], [#1570], [#1572], [#1573], [#1602])
+  ([#1264], [#1330], [#1402], [#1428], [#1430], [#1436], [#1443], [#1446], [#1464], [#1465], [#1470], [#1471], [#1472], [#1474], [#1475], [#1506], [#1510], [#1513], [#1521], [#1542], [#1548], [#1550], [#1554], [#1567], [#1569], [#1570], [#1572], [#1573], [#1602])
   ([**@burgholzer**], [**@denialhaag**], [**@taminob**], [**@DRovara**], [**@li-mingbao**], [**@Ectras**], [**@MatthiasReumann**], [**@simon1hofmann**])
 
 ### Changed
@@ -347,6 +347,7 @@ _📚 Refer to the [GitHub Release Notes](https://github.com/munich-quantum-tool
 [#1570]: https://github.com/munich-quantum-toolkit/core/pull/1570
 [#1569]: https://github.com/munich-quantum-toolkit/core/pull/1569
 [#1568]: https://github.com/munich-quantum-toolkit/core/pull/1568
+[#1567]: https://github.com/munich-quantum-toolkit/core/pull/1567
 [#1565]: https://github.com/munich-quantum-toolkit/core/pull/1565
 [#1564]: https://github.com/munich-quantum-toolkit/core/pull/1564
 [#1554]: https://github.com/munich-quantum-toolkit/core/pull/1554

mlir/include/mlir/Compiler/CompilerPipeline.h

@@ -115,8 +115,8 @@ class QuantumCompilerPipeline {
    * @brief Add canonicalization and cleanup passes
    *
    * @details
-   * Always adds the standard MLIR canonicalization pass followed by dead
-   * value removal.
+   * Always adds the standard MLIR canonicalization pass followed by common
+   * sub-expression elimination and dead value removal.
    */
   static void addCleanupPasses(PassManager& pm);
 

mlir/lib/Compiler/CompilerPipeline.cpp

@@ -46,8 +46,10 @@ static void prettyPrintStage(ModuleOp module, const llvm::StringRef stageName,
 }
 
 void QuantumCompilerPipeline::addCleanupPasses(PassManager& pm) {
-  // Always run canonicalization and dead value removal
+  // Always run canonicalization, common sub-expression elimination, and dead
+  // value removal
   pm.addPass(createCanonicalizerPass());
+  pm.addPass(createCSEPass());
   pm.addPass(createRemoveDeadValuesPass());
 }
 

mlir/lib/Support/Passes.cpp

@@ -20,6 +20,7 @@ using namespace mlir;
 void runCanonicalizationPasses(ModuleOp module) {
   PassManager pm(module.getContext());
   pm.addPass(createCanonicalizerPass());
+  pm.addPass(createCSEPass());
   pm.addPass(createRemoveDeadValuesPass());
   if (pm.run(module).failed()) {
     llvm::errs() << "Failed to run canonicalization passes.\n";

mlir/unittests/Dialect/QC/IR/test_qc_ir.cpp

@@ -914,6 +914,9 @@ INSTANTIATE_TEST_SUITE_P(
         QCTestCase{"StaticQubitsWithInv",
                    MQT_NAMED_BUILDER(staticQubitsWithInv),
                    MQT_NAMED_BUILDER(staticQubitsWithInv)},
+        QCTestCase{"StaticQubitsWithDuplicates",
+                   MQT_NAMED_BUILDER(staticQubitsWithDuplicates),
+                   MQT_NAMED_BUILDER(staticQubitsCanonical)},
         QCTestCase{"AllocDeallocPair", MQT_NAMED_BUILDER(allocDeallocPair),
                    MQT_NAMED_BUILDER(emptyQC)}));
 /// @}

mlir/unittests/Dialect/QIR/IR/test_qir_ir.cpp

@@ -548,5 +548,8 @@ INSTANTIATE_TEST_SUITE_P(
                     MQT_NAMED_BUILDER(staticQubitsWithCtrl)},
         QIRTestCase{"StaticQubitsWithInv",
                     MQT_NAMED_BUILDER(staticQubitsWithInv),
-                    MQT_NAMED_BUILDER(staticQubitsWithInv)}));
+                    MQT_NAMED_BUILDER(staticQubitsWithInv)},
+        QIRTestCase{"StaticQubitsWithDuplicates",
+                    MQT_NAMED_BUILDER(staticQubitsWithDuplicates),
+                    MQT_NAMED_BUILDER(staticQubitsCanonical)}));
 /// @}

mlir/unittests/programs/qc_programs.cpp

@@ -65,6 +65,30 @@ void staticQubitsWithInv(QCProgramBuilder& b) {
   b.inv([&]() { b.t(q0); });
 }
 
+void staticQubitsWithDuplicates(QCProgramBuilder& b) {
+  const auto q0a = b.staticQubit(0);
+  const auto q1a = b.staticQubit(1);
+  const auto q0b = b.staticQubit(0);
+  const auto q1b = b.staticQubit(1);
+
+  b.rx(std::numbers::pi / 4., q0a);
+  b.p(std::numbers::pi / 2., q1a);
+  b.rzz(0.123, q0b, q1b);
+  b.cx(q0b, q1b);
+  b.inv([&]() { b.t(q0a); });
+}
+
+void staticQubitsCanonical(QCProgramBuilder& b) {
+  const auto q0 = b.staticQubit(0);
+  const auto q1 = b.staticQubit(1);
+
+  b.rx(std::numbers::pi / 4., q0);
+  b.p(std::numbers::pi / 2., q1);
+  b.rzz(0.123, q0, q1);
+  b.cx(q0, q1);
+  b.inv([&]() { b.t(q0); });
+}
+
 void allocDeallocPair(QCProgramBuilder& b) {
   auto q = b.allocQubit();
   b.dealloc(q);

mlir/unittests/programs/qc_programs.h

@@ -48,6 +48,13 @@ void staticQubitsWithCtrl(QCProgramBuilder& b);
 /// Allocates a static qubit and applies an inverse modifier.
 void staticQubitsWithInv(QCProgramBuilder& b);
 
+/// Allocates duplicate static qubits and applies operations on both.
+void staticQubitsWithDuplicates(QCProgramBuilder& b);
+
+/// Same as `staticQubitsWithDuplicates`, but with canonical static qubit
+/// retrievals.
+void staticQubitsCanonical(QCProgramBuilder& b);
+
 /// Allocates and explicitly deallocates a single qubit.
 void allocDeallocPair(QCProgramBuilder& b);
 

mlir/unittests/programs/qir_programs.cpp

@@ -65,6 +65,28 @@ void staticQubitsWithInv(QIRProgramBuilder& b) {
   b.tdg(q0);
 }
 
+void staticQubitsWithDuplicates(QIRProgramBuilder& b) {
+  auto q0a = b.staticQubit(0);
+  auto q1a = b.staticQubit(1);
+  auto q0b = b.staticQubit(0);
+  auto q1b = b.staticQubit(1);
+  b.rx(std::numbers::pi / 4., q0a);
+  b.p(std::numbers::pi / 2., q1a);
+  b.rzz(0.123, q0b, q1b);
+  b.cx(q0b, q1b);
+  b.tdg(q0a);
+}
+
+void staticQubitsCanonical(QIRProgramBuilder& b) {
+  auto q0 = b.staticQubit(0);
+  auto q1 = b.staticQubit(1);
+  b.rx(std::numbers::pi / 4., q0);
+  b.p(std::numbers::pi / 2., q1);
+  b.rzz(0.123, q0, q1);
+  b.cx(q0, q1);
+  b.tdg(q0);
+}
+
 void singleMeasurementToSingleBit(QIRProgramBuilder& b) {
   auto q = b.allocQubitRegister(1);
   const auto c = b.allocClassicalBitRegister(1);

mlir/unittests/programs/qir_programs.h

@@ -48,6 +48,13 @@ void staticQubitsWithCtrl(QIRProgramBuilder& b);
 /// Allocates a static qubit and applies the inverse of a T gate (Tdg).
 void staticQubitsWithInv(QIRProgramBuilder& b);
 
+/// Allocates duplicate static qubits and applies operations on both.
+void staticQubitsWithDuplicates(QIRProgramBuilder& b);
+
+/// Same as `staticQubitsWithDuplicates`, but with canonical static qubit
+/// retrievals.
+void staticQubitsCanonical(QIRProgramBuilder& b);
+
 // --- MeasureOp ------------------------------------------------------------ //
 
 /// Measures a single qubit into a single classical bit.