From a2f8d7c5e22b510965327383410bd576f7cf28e7 Mon Sep 17 00:00:00 2001
From: Richard-Qin-X <richard.qin.001@gmail.com>
Date: Thu, 13 Aug 2026 04:17:52 +0800
Subject: [CodeGen] Split machine liveness components

---
 backend/include/rcc/CodeGen/LiveRegUnits.h | 84 ++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 backend/include/rcc/CodeGen/LiveRegUnits.h

(limited to 'backend/include/rcc/CodeGen/LiveRegUnits.h')

diff --git a/backend/include/rcc/CodeGen/LiveRegUnits.h b/backend/include/rcc/CodeGen/LiveRegUnits.h
new file mode 100644
index 0000000..6eb06a6
--- /dev/null
+++ b/backend/include/rcc/CodeGen/LiveRegUnits.h
@@ -0,0 +1,84 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_CODEGEN_LIVEREGUNITS_H
+#define RCC_CODEGEN_LIVEREGUNITS_H
+
+#include "rcc/CodeGen/MachineIRTypes.h"
+#include "rcc/CodeGen/Register.h"
+#include "rcc/Support/Error.h"
+
+#include <cstddef>
+#include <cstdint>
+#include <optional>
+#include <span>
+#include <unordered_map>
+#include <vector>
+
+namespace rcc {
+
+class MachineFunction;
+class MachineInstr;
+class MachineOperand;
+class RegisterMask;
+class TargetDescription;
+struct PhysicalRegisterDesc;
+
+class LiveRegUnits final {
+public:
+  [[nodiscard]] LaneMask lanes(RegisterUnitID Unit) const noexcept;
+  [[nodiscard]] bool contains(RegisterUnitID Unit, LaneMask Lanes = LaneMask::all()) const noexcept;
+  [[nodiscard]] bool intersects(RegisterUnitID Unit,
+                                LaneMask Lanes = LaneMask::all()) const noexcept;
+  [[nodiscard]] bool empty() const noexcept {
+    return Values.empty();
+  }
+
+  void add(RegisterUnitID Unit, LaneMask Lanes);
+  void remove(RegisterUnitID Unit, LaneMask Lanes);
+  void unite(const LiveRegUnits &Other);
+  void subtract(const LiveRegUnits &Other);
+
+  [[nodiscard]] const std::unordered_map<RegisterUnitID, LaneMask> &entries() const noexcept {
+    return Values;
+  }
+
+  friend bool operator==(const LiveRegUnits &, const LiveRegUnits &) = default;
+
+private:
+  std::unordered_map<RegisterUnitID, LaneMask> Values;
+};
+
+struct PhysicalUnitAccess final {
+  RegisterUnitID Unit;
+  LaneMask Lanes;
+};
+
+[[nodiscard]] LaneMask normalizeUnitLanes(LaneMask UnitViewLanes,
+                                          LaneMask RegisterLanes = LaneMask::all()) noexcept;
+[[nodiscard]] LaneMask denormalizeUnitLanes(LaneMask UnitLanes, LaneMask UnitViewLanes) noexcept;
+[[nodiscard]] LaneMask physicalRegisterLanes(const PhysicalRegisterDesc &Description) noexcept;
+[[nodiscard]] LiveRegUnits physicalRegisterCoverage(const PhysicalRegisterDesc &Description,
+                                                    LaneMask Requested = LaneMask::all());
+[[nodiscard]] bool isSubset(const LiveRegUnits &Subset, const LiveRegUnits &Superset) noexcept;
+[[nodiscard]] std::size_t laneCount(const LiveRegUnits &Set) noexcept;
+
+[[nodiscard]] Expected<LaneMask> virtualRegisterLanes(Register Reg, const MachineFunction &Function,
+                                                      const TargetDescription &Target);
+[[nodiscard]] Expected<LaneMask> virtualOperandLanes(const MachineOperand &Operand,
+                                                     const MachineFunction &Function,
+                                                     const TargetDescription &Target);
+[[nodiscard]] Expected<std::vector<PhysicalUnitAccess>>
+physicalOperandUnits(const MachineOperand &Operand, const TargetDescription &Target);
+
+void addPhysicalRegister(LiveRegUnits &Set, const PhysicalRegisterDesc &Description,
+                         LaneMask Requested = LaneMask::all());
+[[nodiscard]] bool isReservedPhysicalRegister(Register Reg, const MachineFunction &Function,
+                                              const TargetDescription &Target) noexcept;
+[[nodiscard]] Expected<void> addRegisterMaskDefs(LiveRegUnits &Set, const RegisterMask &Mask,
+                                                 const TargetDescription &Target);
+[[nodiscard]] Expected<void> addRegisterMaskUses(LiveRegUnits &Set, const RegisterMask &Mask,
+                                                 const TargetDescription &Target);
+
+} // namespace rcc
+
+#endif // RCC_CODEGEN_LIVEREGUNITS_H
-- 
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