From b85a348ab7bdd878fd975121fc2501625eceec95 Mon Sep 17 00:00:00 2001
From: Richard-Qin-X <richard.qin.001@gmail.com>
Date: Fri, 14 Aug 2026 22:37:46 +0800
Subject: [GlobalISel] Legalize G_ABS

---
 backend/include/rcc/CodeGen/GlobalISel/Utils.h | 46 ++++++++++++++------------
 1 file changed, 25 insertions(+), 21 deletions(-)

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

diff --git a/backend/include/rcc/CodeGen/GlobalISel/Utils.h b/backend/include/rcc/CodeGen/GlobalISel/Utils.h
index 5af2fb4..f252454 100644
--- a/backend/include/rcc/CodeGen/GlobalISel/Utils.h
+++ b/backend/include/rcc/CodeGen/GlobalISel/Utils.h
@@ -3,11 +3,13 @@
 #ifndef RCC_CODEGEN_GLOBALISEL_UTILS_H
 #define RCC_CODEGEN_GLOBALISEL_UTILS_H
 
+#include "rcc/ADT/APInt.h"
 #include "rcc/CodeGen/LowLevelType.h"
 #include "rcc/CodeGen/Register.h"
 #include "rcc/Support/Error.h"
 
 #include <cstddef>
+#include <optional>
 #include <span>
 #include <vector>
 
@@ -18,36 +20,38 @@ class MachineInstr;
 class MachineRegisterInfo;
 class TargetDescription;
 
+struct ValueAndVReg final {
+  APInt Value;
+  Register VReg;
+};
+
+[[nodiscard]] std::optional<ValueAndVReg>
+getIConstantVRegValWithLookThrough(Register VReg, const MachineRegisterInfo &MRI,
+                                   bool LookThroughInstrs = true);
+
 /// Check whether an instruction only defines dead virtual registers and has no
 /// observable side effects.
-[[nodiscard]] bool isTriviallyDead(const MachineInstr &Instruction,
-                                   const MachineRegisterInfo &MRI,
+[[nodiscard]] bool isTriviallyDead(const MachineInstr &Instruction, const MachineRegisterInfo &MRI,
                                    const TargetDescription &Target) noexcept;
 
 [[nodiscard]] Expected<void> eraseInstrs(std::span<MachineInstr *const> Instructions,
-                                         MachineRegisterInfo &MRI,
-                                         const TargetDescription &Target);
+                                         MachineRegisterInfo &MRI, const TargetDescription &Target);
 
-[[nodiscard]] Expected<void> eraseInstr(MachineInstr &Instruction,
-                                        MachineRegisterInfo &MRI,
+[[nodiscard]] Expected<void> eraseInstr(MachineInstr &Instruction, MachineRegisterInfo &MRI,
                                         const TargetDescription &Target);
 
-[[nodiscard]] Expected<void> extractParts(Register Reg, LowLevelType Type,
-                                          int PartCount,
+[[nodiscard]] Expected<void> extractParts(Register Reg, LowLevelType Type, int PartCount,
                                           std::vector<Register> &Parts,
-                                          MachineIRBuilder &MIRBuilder,
-                                          MachineRegisterInfo &MRI);
-
-[[nodiscard]] Expected<bool>
-extractParts(Register Reg, LowLevelType RegisterType, LowLevelType MainType,
-             LowLevelType &LeftoverType, std::vector<Register> &Parts,
-             std::vector<Register> &LeftoverParts,
-             MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI);
-
-[[nodiscard]] Expected<LowLevelType> getLCMType(LowLevelType OriginalType,
-                                                LowLevelType TargetType);
-[[nodiscard]] Expected<LowLevelType> getGCDType(LowLevelType OriginalType,
-                                                LowLevelType TargetType);
+                                          MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI);
+
+[[nodiscard]] Expected<bool> extractParts(Register Reg, LowLevelType RegisterType,
+                                          LowLevelType MainType, LowLevelType &LeftoverType,
+                                          std::vector<Register> &Parts,
+                                          std::vector<Register> &LeftoverParts,
+                                          MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI);
+
+[[nodiscard]] Expected<LowLevelType> getLCMType(LowLevelType OriginalType, LowLevelType TargetType);
+[[nodiscard]] Expected<LowLevelType> getGCDType(LowLevelType OriginalType, LowLevelType TargetType);
 
 } // namespace rcc
 
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