✨ Add MQTRef-QIR conversions

mlir/include/mlir/Conversion/CMakeLists.txt

@@ -8,3 +8,5 @@
 
 add_subdirectory(MQTRefToMQTOpt)
 add_subdirectory(MQTOptToMQTRef)
+add_subdirectory(MQTRefToQIR)
+add_subdirectory(QIRToMQTRef)

mlir/include/mlir/Conversion/MQTRefToQIR/CMakeLists.txt

@@ -0,0 +1,13 @@
+# 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
+
+set(LLVM_TARGET_DEFINITIONS MQTRefToQIR.td)
+mlir_tablegen(MQTRefToQIR.h.inc -gen-pass-decls -name MQTRefToQIR)
+add_public_tablegen_target(MQTRefToQIRIncGen)
+
+add_mlir_doc(MQTRefToQIR MLIRMQTRefToQIR Conversions/ -gen-pass-doc)

mlir/include/mlir/Conversion/MQTRefToQIR/MQTRefToQIR.h

@@ -0,0 +1,23 @@
+/*
+ * 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
+ */
+
+#pragma once
+
+#include <mlir/Pass/Pass.h> // from @llvm-project
+
+namespace mqt::ir {
+
+#define GEN_PASS_DECL
+#include "mlir/Conversion/MQTRefToQIR/MQTRefToQIR.h.inc"
+
+#define GEN_PASS_REGISTRATION
+#include "mlir/Conversion/MQTRefToQIR/MQTRefToQIR.h.inc"
+
+} // namespace mqt::ir

mlir/include/mlir/Conversion/MQTRefToQIR/MQTRefToQIR.td

@@ -0,0 +1,33 @@
+// 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
+
+include "mlir/Pass/PassBase.td"
+
+def MQTRefToQIR : Pass<"mqtref-to-qir"> {
+   let summary = "Convert MQT's `Ref` dialect into the llvm dialect that adheres to the QIR specification";
+
+   let description = [{
+      This pass converts all operations to the llvm dialect. The quantum operations of the mqt ref dialect are converted
+      to an equivalent operation in the qir instruction set expressed with a function call in the llvm dialect. This requires a valid
+      input in the mqtref dialect where the main function is marked with the entry_point attribute. At the moment the pass only supports
+      simple quantum programs with a straight controlflow. In order to adhere to the base profile of QIR, the initial module is divided
+      into multiple blocks and an initialize operation is added. During the conversion both QubitType and RegisterType from mqtref are
+      replaced with llvm.ptr type to represent an opaque pointer in the llvm dialect.
+      The remaining operations from the standard dialects are lowered to the llvm dialect via built-in conversion passes from mlir.
+      This includes the following dialects at the moment: func, arith, cf
+
+      Once the module is converted fully in the llvm dialect, one can convert the resulting file into LLVM-IR with the following command:
+      mlir-translate --mlir-to-llvmir input.mlir > output.ll
+   }];
+
+  // Define dependent dialects
+  let dependentDialects = [
+     "::mqt::ir::ref::MQTRefDialect",
+     "mlir::LLVM::LLVMDialect"
+  ];
+}

mlir/include/mlir/Conversion/QIRToMQTRef/CMakeLists.txt

@@ -0,0 +1,13 @@
+# 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
+
+set(LLVM_TARGET_DEFINITIONS QIRToMQTRef.td)
+mlir_tablegen(QIRToMQTRef.h.inc -gen-pass-decls -name QIRToMQTRef)
+add_public_tablegen_target(QIRToMQTRefIncGen)
+
+add_mlir_doc(QIRToMQTRef MLIRQIRToMQTRef Conversions/ -gen-pass-doc)

mlir/include/mlir/Conversion/QIRToMQTRef/QIRToMQTRef.h

@@ -0,0 +1,23 @@
+/*
+ * 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
+ */
+
+#pragma once
+
+#include <mlir/Pass/Pass.h> // from @llvm-project
+
+namespace mqt::ir {
+
+#define GEN_PASS_DECL
+#include "mlir/Conversion/QIRToMQTRef/QIRToMQTRef.h.inc"
+
+#define GEN_PASS_REGISTRATION
+#include "mlir/Conversion/QIRToMQTRef/QIRToMQTRef.h.inc"
+
+} // namespace mqt::ir

mlir/include/mlir/Conversion/QIRToMQTRef/QIRToMQTRef.td

@@ -0,0 +1,32 @@
+// 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
+
+include "mlir/Pass/PassBase.td"
+
+def QIRToMQTRef : Pass<"qir-to-mqtref"> {
+    let summary = "Convert llvm dialect that adheres to the QIR specification to MQT's `Ref` dialect";
+
+    let description = [{
+      This pass converts all llvm.mlir.call operation from the qir instruction set into quantum operations in the mqtref dialect.
+      The pass expects a valid mlir module in the llvm dialect that uses dynamic addressing for the qubit allocation and uses the
+      QIR base profile. At the moment the pass only supports simple quantum programs with a straight controlflow. The conversion
+      of the quantum operation is done checking the function name of the call operation and replacing it with an equivalent operation
+      from the mqtref dialect. Other operations from the llvm dialect like llvm.mlir.constants or function declarations are currently not
+      converted and persist after the conversion. At the moment quantum operations that do not have an equivalent operation in
+      the mqtref dialect are deleted during the conversion.
+
+      The initial .mlir module with the llvm dialect can be obtained by converting a .ll file with the following command:
+      mlir-translate --import-llvm input.ll -o output.mlir
+   }];
+
+  // Define dependent dialects
+  let dependentDialects = [
+    "::mqt::ir::ref::MQTRefDialect",
+    "mlir::LLVM::LLVMDialect"
+  ];
+}

mlir/lib/Conversion/CMakeLists.txt

@@ -8,3 +8,5 @@
 
 add_subdirectory(MQTOptToMQTRef)
 add_subdirectory(MQTRefToMQTOpt)
+add_subdirectory(MQTRefToQIR)
+add_subdirectory(QIRToMQTRef)

mlir/lib/Conversion/MQTRefToQIR/CMakeLists.txt

@@ -0,0 +1,11 @@
+# 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
+
+file(GLOB CONVERSION_SOURCES *.cpp)
+
+add_mlir_library(MQTRefToQIR ${CONVERSION_SOURCES} DEPENDS MQTRefToQIRIncGen)