From b1c08d57f1637f5ee813d1409dacdfa88c1509a0 Mon Sep 17 00:00:00 2001
From: Richard-Qin-X <richard.qin.001@gmail.com>
Date: Fri, 28 Aug 2026 19:15:07 +0800
Subject: [RISCV] Generate complete Zcmp instruction definitions

---
 backend/lib/Target/RISCV/RISCVMCCodeEmitter.cpp | 71 ++++++++++++++++++++-----
 1 file changed, 57 insertions(+), 14 deletions(-)

(limited to 'backend/lib/Target/RISCV/RISCVMCCodeEmitter.cpp')

diff --git a/backend/lib/Target/RISCV/RISCVMCCodeEmitter.cpp b/backend/lib/Target/RISCV/RISCVMCCodeEmitter.cpp
index 339d817..48de3e4 100644
--- a/backend/lib/Target/RISCV/RISCVMCCodeEmitter.cpp
+++ b/backend/lib/Target/RISCV/RISCVMCCodeEmitter.cpp
@@ -102,6 +102,23 @@ namespace {
                         "Zcmp move requires an s0-s7 register");
 }
 
+[[nodiscard]] Expected<std::uint16_t> encodeZcmpMove(const mc::MCInst &Instruction,
+                                                     const TargetDescription &Target,
+                                                     const AssemblyInstructionInfo &Assembly) {
+  auto Count = requireOperandCount(Instruction, 2);
+  if (!Count)
+    return std::unexpected(Count.error());
+  auto First = savedRegisterEncoding(Instruction, 0, Target);
+  auto Second = savedRegisterEncoding(Instruction, 1, Target);
+  if (!First)
+    return std::unexpected(First.error());
+  if (!Second)
+    return std::unexpected(Second.error());
+  const auto Encoding = static_cast<std::uint16_t>(Assembly.Encoding);
+  return static_cast<std::uint16_t>((Encoding & ~std::uint16_t{0x039c}) | *First << 7U |
+                                    *Second << 2U);
+}
+
 [[nodiscard]] bool fitsSigned(std::int64_t Value, unsigned Bits) noexcept {
   const std::int64_t Minimum = -(std::int64_t{1} << (Bits - 1U));
   const std::int64_t Maximum = (std::int64_t{1} << (Bits - 1U)) - 1;
@@ -190,6 +207,32 @@ namespace {
   return 0;
 }
 
+[[nodiscard]] Expected<std::uint16_t> encodeZcmpStack(const mc::MCInst &Instruction,
+                                                      const AssemblyInstructionInfo &Assembly,
+                                                      mc::MCEncodedInstruction &Result) {
+  auto Count = requireOperandCount(Instruction, 2);
+  if (!Count)
+    return std::unexpected(Count.error());
+  auto RegisterList = immediateOrFixup(Instruction, 0, mc::fixup_kind::None, false, Result);
+  auto StackAdjustment = immediateOrFixup(Instruction, 1, mc::fixup_kind::None, false, Result);
+  if (!RegisterList)
+    return std::unexpected(RegisterList.error());
+  if (!StackAdjustment)
+    return std::unexpected(StackAdjustment.error());
+  if (*RegisterList < 4 || *RegisterList > 15) {
+    return makeUnexpected(ErrorCode::InstructionEncodingFailed,
+                          "Zcmp register list encoding is out of range");
+  }
+  if (*StackAdjustment < 0 || *StackAdjustment > 48 || *StackAdjustment % 16 != 0) {
+    return makeUnexpected(ErrorCode::InstructionEncodingFailed,
+                          "Zcmp stack adjustment must be 0, 16, 32, or 48");
+  }
+  const auto Encoding = static_cast<std::uint16_t>(Assembly.Encoding);
+  return static_cast<std::uint16_t>((Encoding & ~std::uint16_t{0x00fc}) |
+                                    static_cast<std::uint16_t>(*RegisterList) << 4U |
+                                    static_cast<std::uint16_t>(*StackAdjustment >> 4U) << 2U);
+}
+
 [[nodiscard]] Expected<mc::MCFixupKind> uFixupKind(const mc::MCOperand &Operand) {
   auto Kind = expressionTargetKind(Operand);
   if (!Kind)
@@ -663,20 +706,6 @@ namespace {
     return immediateOrFixup(Instruction, Index, Kind, PCRelative, Result);
   };
 
-  if (Opcode == InstructionOpcode::CM_MVA01S || Opcode == InstructionOpcode::CM_MVSA01) {
-    auto Count = requireOperandCount(Instruction, 2);
-    if (!Count)
-      return std::unexpected(Count.error());
-    auto First = savedRegisterEncoding(Instruction, 0, Target);
-    auto Second = savedRegisterEncoding(Instruction, 1, Target);
-    if (!First)
-      return std::unexpected(First.error());
-    if (!Second)
-      return std::unexpected(Second.error());
-    return static_cast<std::uint16_t>((Encoding & ~std::uint16_t{0x039c}) | *First << 7U |
-                                      *Second << 2U);
-  }
-
   if (Opcode == InstructionOpcode::C_ADDI4SPN) {
     auto Count = requireOperandCount(Instruction, 2);
     if (!Count)
@@ -1020,6 +1049,20 @@ RISCVMCCodeEmitter::encodeInstruction(const mc::MCInst &Instruction) const {
     appendLittleEndian(Result, *Compressed, 2);
     return Result;
   }
+  case EncodingCategory::ZCMP_MOVE: {
+    auto ZcmpMove = encodeZcmpMove(Instruction, *Target, *Assembly);
+    if (!ZcmpMove)
+      return std::unexpected(ZcmpMove.error());
+    appendLittleEndian(Result, *ZcmpMove, 2);
+    return Result;
+  }
+  case EncodingCategory::ZCMP_STACK: {
+    auto ZcmpStack = encodeZcmpStack(Instruction, *Assembly, Result);
+    if (!ZcmpStack)
+      return std::unexpected(ZcmpStack.error());
+    appendLittleEndian(Result, *ZcmpStack, 2);
+    return Result;
+  }
   case EncodingCategory::None:
     break;
   }
-- 
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