Continue implementign merge pass [skip CI]

Author: denialhaag

mlir/include/mlir/Dialect/MQTOpt/IR/MQTOptInterfaces.td

@@ -140,6 +140,24 @@ def UnitaryInterface : OpInterface<"UnitaryInterface"> {
                 operands.insert(operands.end(), outQubits.begin(), outQubits.end());
                 operands.insert(operands.end(), controls.begin(), controls.end());
                 return operands;
+            }]>,
+        InterfaceMethod<
+            /*desc=*/        "Get params.",
+            /*returnType=*/  "Variadic<F64>",
+            /*methodName=*/  "getParams",
+            /*args=*/        (ins),
+            /*methodBody=*/  [{}],
+            /*defaultImpl=*/ [{
+                return $_op.getParams();
+            }]>,
+        InterfaceMethod<
+            /*desc=*/        "Set params.",
+            /*returnType=*/  "void",
+            /*methodName=*/  "setParams",
+            /*args=*/        (ins Variadic<F64>:$values),
+            /*methodBody=*/  [{}],
+            /*defaultImpl=*/ [{
+                return $_op.setParams(values);
             }]>
     ];
 

mlir/lib/Dialect/MQTOpt/Transforms/MergeRotationGatesPattern.cpp

@@ -96,15 +96,13 @@ struct MergeRotationGatesPattern final
                mlir::PatternRewriter& rewriter) const override {
     auto user = mlir::dyn_cast<UnitaryInterface>(*op->getUsers().begin());
 
-    // Something like this
-    // I probably need to extend MQTOptInterfaces.td
-    // p1 = op.getParams();
-    // p2 = user.getParams();
-    // p = p1 + p2;
-    // new = user.clone();
-    // new.setParams(p);
-    // rewriter.replaceOp(user, new);
-    // rewriter.eraseOp(op);
+    double p1 = op.getParams()[0];
+    double p2 = user.getParams()[0];
+    double p = p1 + p2;
+    auto newOp = user.clone();
+    newOp.setParams(p);
+    rewriter.replaceOp(user, newOp);
+    rewriter.eraseOp(op);
   }
 };
 

mlir/test/Dialect/MQTOpt/Transforms/merge-rotation-gates.mlir

@@ -0,0 +1,35 @@
+// Copyright (c) 2023 - 2025 Chair for Design Automation, TUM
+// Copyright (c) 2025 Munich Quantum Software Company GmbH
+// All rights reserved.
+//
+// SPDX-License-Identifier: MIT
+//
+// Licensed under the MIT License
+
+// RUN: quantum-opt %s -split-input-file --merge-rotation-gates | FileCheck %s
+
+module {
+  func.func @testMergeSingleQubitGates() {
+    // CHECK: %[[Reg_0:.*]] = "mqtopt.allocQubitRegister"
+    %reg_0 = "mqtopt.allocQubitRegister"() <{size_attr = 2 : i64}> : () -> !mqtopt.QubitRegister
+
+    // CHECK: %[[Reg_1:.*]], %[[Q0_0:.*]] = "mqtopt.extractQubit"(%[[Reg_0]]) <{index_attr = 0 : i64}>
+    %reg_1, %q0_0 = "mqtopt.extractQubit"(%reg_0) <{index_attr = 0 : i64}> : (!mqtopt.QubitRegister) -> (!mqtopt.QubitRegister, !mqtopt.Qubit)
+    // CHECK: %[[Reg_2:.*]], %[[Q1_0:.*]] = "mqtopt.extractQubit"(%[[Reg_1]]) <{index_attr = 1 : i64}>
+    %reg_2, %q1_0 = "mqtopt.extractQubit"(%reg_1) <{index_attr = 1 : i64}> : (!mqtopt.QubitRegister) -> (!mqtopt.QubitRegister, !mqtopt.Qubit)
+
+    // ========================== Check for operation that should be merged ==========================
+    // CHECK: %[[Q0_1:.*]] = mqtopt.rx(2.0) %[[Q0_0]] : !mqtopt.Qubit
+
+    %q0_1 = mqtopt.rx(1.0) %q0_0 : !mqtopt.Qubit
+    %q0_2 = mqtopt.rx(1.0) %q0_1 : !mqtopt.Qubit
+
+    // CHECK: %[[Reg_3:.*]] = "mqtopt.insertQubit"(%[[Reg_2]], %[[Q0_1]])  <{index_attr = 0 : i64}>
+    %reg_3 = "mqtopt.insertQubit"(%reg_2, %q0_3) <{index_attr = 0 : i64}> : (!mqtopt.QubitRegister, !mqtopt.Qubit) -> !mqtopt.QubitRegister
+    // CHECK: %[[Reg_4:.*]] = "mqtopt.insertQubit"(%[[Reg_3]], %[[Q1_0]])  <{index_attr = 1 : i64}>
+    %reg_4 = "mqtopt.insertQubit"(%reg_3, %q1_6) <{index_attr = 1 : i64}> : (!mqtopt.QubitRegister, !mqtopt.Qubit) -> !mqtopt.QubitRegister
+    // CHECK: "mqtopt.deallocQubitRegister"(%[[Reg_4]])
+    "mqtopt.deallocQubitRegister"(%reg_4) : (!mqtopt.QubitRegister) -> ()
+    return
+  }
+}