✨ Add Dead Gate Elimination Pattern

CHANGELOG.md

@@ -18,7 +18,7 @@ This project adheres to [Semantic Versioning], with the exception that minor rel
 - ✨ Add conversions between `jeff` and QCO ([#1479], [#1548], [#1565], [#1637], [#1676], [#1706]) ([**@denialhaag**], [**@burgholzer**])
 - ✨ Add a `place-and-route` pass for mapping circuits to architectures with restricted topologies ([#1537], [#1547], [#1568], [#1581], [#1583], [#1588], [#1600], [#1664], [#1709], [#1716], [#1748]) ([**@MatthiasReumann**], [**@burgholzer**])
 - ✨ 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], [#1567], [#1569], [#1570], [#1572], [#1573], [#1580], [#1602], [#1620], [#1623], [#1624], [#1626], [#1627], [#1635], [#1638], [#1673], [#1675], [#1700], [#1717], [#1728], [#1730], [#1749])
+  ([#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], [#1580], [#1602], [#1620], [#1623], [#1624], [#1626], [#1627], [#1635], [#1638], [#1673], [#1675], [#1700], [#1717], [#1728], [#1730], [#1749], [#1755])
   ([**@burgholzer**], [**@denialhaag**], [**@taminob**], [**@DRovara**], [**@li-mingbao**], [**@Ectras**], [**@MatthiasReumann**], [**@simon1hofmann**])
 
 ### Changed
@@ -402,6 +402,7 @@ _📚 Refer to the [GitHub Release Notes](https://github.com/munich-quantum-tool
 
 <!-- PR links -->
 
+[#1755]: https://github.com/munich-quantum-toolkit/core/pull/1755
 [#1749]: https://github.com/munich-quantum-toolkit/core/pull/1749
 [#1748]: https://github.com/munich-quantum-toolkit/core/pull/1748
 [#1737]: https://github.com/munich-quantum-toolkit/core/pull/1737

mlir/include/mlir/Dialect/QCO/Builder/QCOProgramBuilder.h

@@ -78,14 +78,32 @@ class QCOProgramBuilder final : public ImplicitLocOpBuilder {
   //===--------------------------------------------------------------------===//
 
   /**
-   * @brief Initialize the builder and prepare for program construction
+   * @brief Initialize the builder and prepare for program construction, with
+   * a default return type of i64.
    *
    * @details
    * Creates a main function with an entry_point attribute. Must be called
    * before adding operations.
    */
   void initialize();
 
+  /**
+   * @brief Initialize the builder and prepare for program construction
+   * with specified return types.
+   * @param returnTypes The return types for the main function
+   *
+   * @details
+   * Creates a main function with an entry_point attribute. Must be called
+   * before adding operations.
+   */
+  void initialize(TypeRange returnTypes);
+
+  /**
+   * @brief Modify the return types of the main function after initialization.
+   * @param returnTypes The new return types for the main function
+   */
+  void retype(TypeRange returnTypes);
+
   //===--------------------------------------------------------------------===//
   // Constants
   //===--------------------------------------------------------------------===//
@@ -372,7 +390,7 @@ class QCOProgramBuilder final : public ImplicitLocOpBuilder {
    *
    * @param qubit Input qubit (must be valid/unconsumed)
    * @param bit The classical bit to record the result
-   * @return Output qubit value
+   * @return Pair of (output_qubit, measurement_result)
    *
    * @par Example:
    * ```c++
@@ -382,7 +400,7 @@ class QCOProgramBuilder final : public ImplicitLocOpBuilder {
    * %q0_out, %r0 = qco.measure("c", 3, 0) %q0 : !qco.qubit
    * ```
    */
-  Value measure(Value qubit, const Bit& bit);
+  std::pair<Value, Value> measure(Value qubit, const Bit& bit);
 
   /**
    * @brief Reset a qubit to |0⟩ state
@@ -1375,6 +1393,25 @@ class QCOProgramBuilder final : public ImplicitLocOpBuilder {
    */
   OwningOpRef<ModuleOp> finalize();
 
+  /**
+   * @brief Finalize the program with a given exit code and return the
+   * constructed module
+   * @param returnValues Values representing the exit code to return
+   *
+   * @details
+   * Automatically deallocates all remaining valid qubits and tensors of qubits,
+   * adds a return statement with a given exit code,
+   * and transfers ownership of the module to the caller. The builder should not
+   * be used after calling this method.
+   *
+   * The return values must have the types indicated by the function signature
+   * of the main function, which returns an `i64` by default and can be
+   * modified by passing different arguments to the `initialize()` method.
+   *
+   * @return OwningOpRef containing the constructed quantum program module
+   */
+  OwningOpRef<ModuleOp> finalize(ValueRange returnValues);
+
   /**
    * @brief Convenience method for building quantum programs
    * @param context The MLIR context to use for building the program
@@ -1388,6 +1425,22 @@ class QCOProgramBuilder final : public ImplicitLocOpBuilder {
   build(MLIRContext* context,
         const function_ref<void(QCOProgramBuilder&)>& buildFunc);
 
+  /**
+   * @brief Convenience method for building quantum programs with returns.
+   * @param context The MLIR context to use for building the program
+   * @param returnTypes The types of the values to be returned by the program.
+   * @param buildFunc A function that takes a reference to a QCOProgramBuilder
+   * and uses it to build the desired quantum program. The builder will be
+   * properly initialized before calling this function, and the resulting module
+   * will be finalized using the returned ValueRange after this function
+   * completes.
+   * @return The module containing the quantum program built by buildFunc.
+   */
+  static OwningOpRef<ModuleOp> buildWithReturn(
+      MLIRContext* context,
+      const function_ref<std::pair<SmallVector<Value>, SmallVector<Type>>(
+          QCOProgramBuilder&)>& buildFunc);
+
 private:
   enum class AllocationMode : uint8_t { Unset, Static, Dynamic };
 

mlir/include/mlir/Dialect/QCO/IR/QCODialect.td

@@ -38,6 +38,8 @@ def QCODialect : Dialect {
   let cppNamespace = "::mlir::qco";
 
   let useDefaultTypePrinterParser = 1;
+
+  let hasCanonicalizer = 1;
 }
 
 #endif // MLIR_DIALECT_QCO_IR_QCODIALECT_TD