From 1b4601c1ac91a06091610e969e70bcd1cb014cc5 Mon Sep 17 00:00:00 2001
From: Richard-Qin-X <richard.qin.001@gmail.com>
Date: Mon, 24 Aug 2026 18:13:23 +0800
Subject: [RISCV] Match LLVM large call frame lowering

---
 backend/lib/CodeGen/LiveVariables.cpp | 20 ++++++++++++--------
 backend/lib/CodeGen/MIRPrinter.cpp    |  2 +-
 2 files changed, 13 insertions(+), 9 deletions(-)

(limited to 'backend/lib/CodeGen')

diff --git a/backend/lib/CodeGen/LiveVariables.cpp b/backend/lib/CodeGen/LiveVariables.cpp
index 201e09e..8bdd23e 100644
--- a/backend/lib/CodeGen/LiveVariables.cpp
+++ b/backend/lib/CodeGen/LiveVariables.cpp
@@ -441,10 +441,11 @@ struct LivenessRebuildPlan final {
   std::vector<OperandFlagPlan> Operands;
 };
 
-[[nodiscard]] Expected<bool>
-liveSetIntersects(const MachineOperand &Operand, const RegisterLaneSet &Virtual,
-                  const LiveRegUnits &Physical, const MachineFunction &Function,
-                  const TargetDescription &Target, bool TreatReservedAsLive) {
+[[nodiscard]] Expected<bool> liveSetIntersects(const MachineOperand &Operand,
+                                               const RegisterLaneSet &Virtual,
+                                               const LiveRegUnits &Physical,
+                                               const MachineFunction &Function,
+                                               const TargetDescription &Target) {
   const Register *Reg = Operand.getIf<Register>();
   if (Reg == nullptr || Reg->isNoRegister())
     return false;
@@ -454,8 +455,6 @@ liveSetIntersects(const MachineOperand &Operand, const RegisterLaneSet &Virtual,
       return std::unexpected(Lanes.error());
     return Virtual.intersects(*Reg, *Lanes);
   }
-  if (TreatReservedAsLive && isReservedPhysicalRegister(*Reg, Function, Target))
-    return true;
   auto Units = physicalOperandUnits(Operand, Target);
   if (!Units)
     return std::unexpected(Units.error());
@@ -546,6 +545,11 @@ liveSetIntersects(const MachineOperand &Operand, const RegisterLaneSet &Virtual,
     for (const MachineOperand &Operand : Instruction->operands()) {
       if (!Operand.isRegister() || !Operand.isUse())
         continue;
+      const Register *Reg = Operand.getIf<Register>();
+      if (Reg != nullptr && Reg->isPhysical() &&
+          isReservedPhysicalRegister(*Reg, Function, Target)) {
+        continue;
+      }
       auto Added = addOperandToLiveSet(Operand, Virtual, Physical, Function, Target);
       if (!Added)
         return std::unexpected(Added.error());
@@ -600,7 +604,7 @@ buildLivenessRebuildPlan(const MachineFunction &Function, const TargetDescriptio
         const MachineOperand *Operand = Instruction->operandAt(Index);
         if (Operand == nullptr || !Operand->isRegister() || !Operand->isDef())
           continue;
-        auto IsLive = liveSetIntersects(*Operand, Virtual, Physical, Function, Target, false);
+        auto IsLive = liveSetIntersects(*Operand, Virtual, Physical, Function, Target);
         if (!IsLive)
           return std::unexpected(IsLive.error());
         RegisterOperandFlags Flags = Operand->registerFlags();
@@ -656,7 +660,7 @@ buildLivenessRebuildPlan(const MachineFunction &Function, const TargetDescriptio
                                    !Operand->registerValue()->isNoRegister();
         bool IsKill = false;
         if (IsSemanticUse) {
-          auto IsLive = liveSetIntersects(*Operand, Virtual, Physical, Function, Target, true);
+          auto IsLive = liveSetIntersects(*Operand, Virtual, Physical, Function, Target);
           if (!IsLive)
             return std::unexpected(IsLive.error());
           IsKill = !*IsLive;
diff --git a/backend/lib/CodeGen/MIRPrinter.cpp b/backend/lib/CodeGen/MIRPrinter.cpp
index 4683a81..3708053 100644
--- a/backend/lib/CodeGen/MIRPrinter.cpp
+++ b/backend/lib/CodeGen/MIRPrinter.cpp
@@ -1530,7 +1530,7 @@ namespace {
 
 [[nodiscard]] std::string hexadecimalWords(std::span<const std::uint64_t> Words,
                                            std::uint32_t BitWidth) {
-  constexpr std::string_view Hex = "0123456789ABCDEF";
+  constexpr std::string_view Hex = "0123456789abcdef";
   const std::size_t DigitCount = (static_cast<std::size_t>(BitWidth) + 3U) / 4U;
   std::string Result(DigitCount, '0');
   for (std::size_t Digit = 0; Digit < DigitCount; ++Digit) {
-- 
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