From 596b0ee334432bd9409e498c47836ada52399997 Mon Sep 17 00:00:00 2001
From: mxr <>
Date: Fri, 10 Apr 2026 23:16:12 +0800
Subject: [PATCH] =?UTF-8?q?feat(mir)=E6=B7=BB=E5=8A=A0Movk=E6=8C=87?=
 =?UTF-8?q?=E4=BB=A4=E5=8A=A0=E8=BD=BD=E5=A4=A7=E7=AB=8B=E5=8D=B3=E6=95=B0?=
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---
 include/mir/MIR.h      |  3 +++
 src/mir/AsmPrinter.cpp |  4 ++++
 src/mir/Lowering.cpp   | 42 ++++++++++++++++++++++++++++++++++++++----
 3 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/include/mir/MIR.h b/include/mir/MIR.h
index ff1ce75..6c5f1ea 100644
--- a/include/mir/MIR.h
+++ b/include/mir/MIR.h
@@ -130,6 +130,9 @@ enum class Opcode {
   // ---------- 特殊 ----------
   Nop,          // 空操作: NOP
   Label,        // 内联标签，不生成实际指令，仅输出标签名
+
+  // 添加
+  Movk,   // movk Rd, #imm16, lsl #shift
 };
 
 // ========== 操作数类 ==========
diff --git a/src/mir/AsmPrinter.cpp b/src/mir/AsmPrinter.cpp
index 07d1452..d8c2fd8 100644
--- a/src/mir/AsmPrinter.cpp
+++ b/src/mir/AsmPrinter.cpp
@@ -316,6 +316,10 @@ void PrintInstruction(std::ostream& os, const MachineInstr& instr,
     case Opcode::Label:
       os << ops.at(0).GetLabel() << ":\n";
       break;
+    case Opcode::Movk:
+      os << "  movk " << PhysRegName(ops.at(0).GetReg()) << ", #"
+         << ops.at(1).GetImm() << ", lsl #" << ops.at(2).GetImm() << "\n";
+      break;
     default:
       os << "  // unknown instruction\n";
       break;
diff --git a/src/mir/Lowering.cpp b/src/mir/Lowering.cpp
index 013aa26..c05bf35 100644
--- a/src/mir/Lowering.cpp
+++ b/src/mir/Lowering.cpp
@@ -128,9 +128,34 @@ void EmitValueToReg(const ir::Value* value, PhysReg target,
   if (value == nullptr) {
     DEBUG_MSG( "EmitValueToReg called with null value\n");
   }
+
+  // 辅助函数：判断32位立即数是否可用单条 movz/movn 编码
+  auto isLegalMovImm = [](uint32_t imm) -> bool {
+    // 检查是否可以通过 movz 或 movn 表示（16位立即数，可左移0/16/32/48位）
+    // 对于32位寄存器，只考虑 lsl 0 或 16
+    if ((imm & 0xFFFF) == imm) return true;               // 低16位，lsl #0
+    if ((imm & 0xFFFF0000) == imm) return true;          // 高16位，lsl #16
+    // 可选：检查 movn 情况（~imm 满足上述条件），为了简单可不做，直接返回 false
+    return false;
+  };
+
   if (auto* constant = dynamic_cast<const ir::ConstantInt*>(value)) {
-    block.Append(Opcode::MovImm,
-                 {Operand::Reg(target), Operand::Imm(constant->GetValue())});
+    uint32_t imm = static_cast<uint32_t>(constant->GetValue());
+    if (isLegalMovImm(imm)) {
+      block.Append(Opcode::MovImm,
+                   {Operand::Reg(target), Operand::Imm(static_cast<int64_t>(imm))});
+    } else {
+      // 分解为 movz (低16位) + movk (高16位)
+      uint16_t low = imm & 0xFFFF;
+      uint16_t high = (imm >> 16) & 0xFFFF;
+      block.Append(Opcode::MovImm,
+                   {Operand::Reg(target), Operand::Imm(low)});   // 先加载低16位
+      if (high != 0) {
+        // 使用 Movk 指令写入高16位
+        block.Append(Opcode::Movk,
+                     {Operand::Reg(target), Operand::Imm(high), Operand::Imm(16)});
+      }
+    }
     return;
   }
   // 处理浮点常量
@@ -150,8 +175,17 @@ void EmitValueToReg(const ir::Value* value, PhysReg target,
         float fval = fconstant->GetValue();
         uint32_t int_val = FloatToBits(fval);
         
-        // 使用临时寄存器加载常量并存储
-        block.Append(Opcode::MovImm, {Operand::Reg(PhysReg::W8), Operand::Imm(static_cast<int>(int_val))});
+        // 同样需要对 int_val 进行大立即数分解
+        if (isLegalMovImm(int_val)) {
+          block.Append(Opcode::MovImm, {Operand::Reg(PhysReg::W8), Operand::Imm(static_cast<int64_t>(int_val))});
+        } else {
+          uint16_t low = int_val & 0xFFFF;
+          uint16_t high = (int_val >> 16) & 0xFFFF;
+          block.Append(Opcode::MovImm, {Operand::Reg(PhysReg::W8), Operand::Imm(low)});
+          if (high != 0) {
+            block.Append(Opcode::Movk, {Operand::Reg(PhysReg::W8), Operand::Imm(high), Operand::Imm(16)});
+          }
+        }
         block.Append(Opcode::StoreStack, {Operand::Reg(PhysReg::W8), Operand::FrameIndex(slot)});
         const_cast<ValueSlotMap&>(slots).emplace(value, slot);
     } else {