#include "irgen/IRGen.h"

#include <stdexcept>
#include <string>

#include "SysYParser.h"
#include "ir/IR.h"
#include "sem/func.h"
#include "utils/Log.h"

// ─── 辅助 ─────────────────────────────────────────────────────────────────────

// 把 i32 值转成 i1（icmp ne i32 v, 0）
ir::Value* IRGenImpl::ToI1(ir::Value* v) {
  if (!v) throw std::runtime_error(FormatError("irgen", "ToI1: null value"));
  if (v->IsInt1()) return v;
  return builder_.CreateICmp(ir::ICmpPredicate::NE, v,
                             builder_.CreateConstInt(0),
                             module_.GetContext().NextTemp());
}

// 把 i1 值零扩展为 i32
ir::Value* IRGenImpl::ToI32(ir::Value* v) {
  if (!v) throw std::runtime_error(FormatError("irgen", "ToI32: null value"));
  if (v->IsInt32()) return v;
  return builder_.CreateZExt(v, module_.GetContext().NextTemp());
}

// 转换为 float（如果是 int）
ir::Value* IRGenImpl::ToFloat(ir::Value* v) {
  if (!v) throw std::runtime_error(FormatError("irgen", "ToFloat: null value"));
  if (v->IsFloat32()) return v;
  if (v->IsInt32()) return builder_.CreateSIToFP(v, module_.GetContext().NextTemp());
  if (v->IsInt1()) {
    auto* i32 = ToI32(v);
    return builder_.CreateSIToFP(i32, module_.GetContext().NextTemp());
  }
  throw std::runtime_error(FormatError("irgen", "ToFloat: 不支持的类型"));
}

// 转换为 int（如果是 float）
ir::Value* IRGenImpl::ToInt(ir::Value* v) {
  if (!v) throw std::runtime_error(FormatError("irgen", "ToInt: null value"));
  if (v->IsInt32()) return v;
  if (v->IsFloat32()) return builder_.CreateFPToSI(v, module_.GetContext().NextTemp());
  if (v->IsInt1()) return ToI32(v);
  throw std::runtime_error(FormatError("irgen", "ToInt: 不支持的类型"));
}

// 隐式类型转换：确保两个操作数类型一致（int 转 float）
void IRGenImpl::ImplicitConvert(ir::Value*& lhs, ir::Value*& rhs) {
  if (!lhs || !rhs) return;
  bool lhs_float = lhs->IsFloat32();
  bool rhs_float = rhs->IsFloat32();
  if (lhs_float && !rhs_float) {
    rhs = ToFloat(rhs);
  } else if (!lhs_float && rhs_float) {
    lhs = ToFloat(lhs);
  }
}

// 求值 exp（i32）
ir::Value* IRGenImpl::EvalExpr(SysYParser::ExpContext& expr) {
  auto result = expr.accept(this);
  return std::any_cast<ir::Value*>(result);
}

// 求值 addExp（i32）
ir::Value* IRGenImpl::EvalExprAdd(SysYParser::AddExpContext& expr) {
  auto result = expr.accept(this);
  return std::any_cast<ir::Value*>(result);
}

// 求值 cond（i1）
ir::Value* IRGenImpl::EvalCond(SysYParser::CondContext& cond) {
  auto result = cond.accept(this);
  auto* v = std::any_cast<ir::Value*>(result);
  return ToI1(v);
}

// 注册外部函数声明（幂等）
void IRGenImpl::EnsureExternalDecl(const std::string& name) {
  if (module_.HasExternalDecl(name) || module_.GetFunction(name)) return;
  // SysY 标准运行库函数签名
  if (name == "getint") {
    module_.DeclareExternalFunc(name, ir::Type::GetInt32Type(), {});
  } else if (name == "getch") {
    module_.DeclareExternalFunc(name, ir::Type::GetInt32Type(), {});
  } else if (name == "getfloat") {
    module_.DeclareExternalFunc(name, ir::Type::GetVoidType(), {});  // 近似
  } else if (name == "putint") {
    module_.DeclareExternalFunc(name, ir::Type::GetVoidType(),
                                {ir::Type::GetInt32Type()});
  } else if (name == "putch") {
    module_.DeclareExternalFunc(name, ir::Type::GetVoidType(),
                                {ir::Type::GetInt32Type()});
  } else if (name == "putfloat") {
    module_.DeclareExternalFunc(name, ir::Type::GetVoidType(), {});
  } else if (name == "putarray") {
    module_.DeclareExternalFunc(name, ir::Type::GetVoidType(),
                                {ir::Type::GetInt32Type()});
  } else if (name == "starttime" || name == "stoptime") {
    module_.DeclareExternalFunc(name, ir::Type::GetVoidType(),
                                {ir::Type::GetInt32Type()});
  } else {
    // 未知外部函数，按 i32 返回声明
    module_.DeclareExternalFunc(name, ir::Type::GetInt32Type(), {});
  }
}

// ─── 表达式访问器（返回 ir::Value*，i32） ─────────────────────────────────────

std::any IRGenImpl::visitExp(SysYParser::ExpContext* ctx) {
  if (!ctx || !ctx->addExp()) {
    throw std::runtime_error(FormatError("irgen", "非法表达式"));
  }
  return ctx->addExp()->accept(this);
}

// addExp : mulExp (AddOp mulExp)*
std::any IRGenImpl::visitAddExp(SysYParser::AddExpContext* ctx) {
  if (!ctx) {
    throw std::runtime_error(FormatError("irgen", "非法加减表达式"));
  }
  auto muls = ctx->mulExp();
  if (muls.empty()) {
    throw std::runtime_error(FormatError("irgen", "addExp 缺少操作数"));
  }

  ir::Value* result = std::any_cast<ir::Value*>(muls[0]->accept(this));
  auto ops = ctx->AddOp();

  for (size_t i = 0; i < ops.size(); ++i) {
    ir::Value* rhs = std::any_cast<ir::Value*>(muls[i + 1]->accept(this));
    ImplicitConvert(result, rhs);
    std::string tmp = module_.GetContext().NextTemp();
    std::string op = ops[i]->getText();
    if (result->IsFloat32()) {
      result = (op == "+") ? builder_.CreateFAdd(result, rhs, tmp)
                           : builder_.CreateFSub(result, rhs, tmp);
    } else {
      result = (op == "+") ? builder_.CreateAdd(result, rhs, tmp)
                           : builder_.CreateSub(result, rhs, tmp);
    }
  }
  return static_cast<ir::Value*>(result);
}

// mulExp : unaryExp (MulOp unaryExp)*
std::any IRGenImpl::visitMulExp(SysYParser::MulExpContext* ctx) {
  if (!ctx) {
    throw std::runtime_error(FormatError("irgen", "非法乘除表达式"));
  }
  auto unarys = ctx->unaryExp();
  if (unarys.empty()) {
    throw std::runtime_error(FormatError("irgen", "mulExp 缺少操作数"));
  }

  ir::Value* result = std::any_cast<ir::Value*>(unarys[0]->accept(this));
  auto ops = ctx->MulOp();

  for (size_t i = 0; i < ops.size(); ++i) {
    ir::Value* rhs = std::any_cast<ir::Value*>(unarys[i + 1]->accept(this));
    ImplicitConvert(result, rhs);
    std::string tmp = module_.GetContext().NextTemp();
    std::string op = ops[i]->getText();
    if (result->IsFloat32()) {
      if (op == "*") result = builder_.CreateFMul(result, rhs, tmp);
      else if (op == "/") result = builder_.CreateFDiv(result, rhs, tmp);
      else throw std::runtime_error(FormatError("irgen", "float 不支持取模"));
    } else {
      if (op == "*") result = builder_.CreateMul(result, rhs, tmp);
      else if (op == "/") result = builder_.CreateDiv(result, rhs, tmp);
      else result = builder_.CreateMod(result, rhs, tmp);
    }
  }
  return static_cast<ir::Value*>(result);
}

// unaryExp : primaryExp
//          | Ident L_PAREN (funcRParams)? R_PAREN
//          | unaryOp unaryExp
std::any IRGenImpl::visitUnaryExp(SysYParser::UnaryExpContext* ctx) {
  if (!ctx) {
    throw std::runtime_error(FormatError("irgen", "非法一元表达式"));
  }

  // ── 一元运算符 ─────────────────────────────────────────────────────────────
  if (ctx->unaryOp() && ctx->unaryExp()) {
    ir::Value* operand =
        std::any_cast<ir::Value*>(ctx->unaryExp()->accept(this));
    std::string op = ctx->unaryOp()->getText();
    if (op == "-") {
      if (operand->IsFloat32()) {
        return static_cast<ir::Value*>(
            builder_.CreateFSub(builder_.CreateConstFloat(0.0f), operand,
                               module_.GetContext().NextTemp()));
      } else {
        return static_cast<ir::Value*>(
            builder_.CreateSub(builder_.CreateConstInt(0), operand,
                              module_.GetContext().NextTemp()));
      }
    } else if (op == "+") {
      return static_cast<ir::Value*>(operand);
    } else if (op == "!") {
      ir::Value* cmp;
      if (operand->IsFloat32()) {
        cmp = builder_.CreateFCmp(ir::FCmpPredicate::OEQ, operand,
                                  builder_.CreateConstFloat(0.0f),
                                  module_.GetContext().NextTemp());
      } else {
        operand = ToI32(operand);
        cmp = builder_.CreateICmp(ir::ICmpPredicate::EQ, operand,
                                  builder_.CreateConstInt(0),
                                  module_.GetContext().NextTemp());
      }
      return static_cast<ir::Value*>(ToI32(cmp));
    }
    throw std::runtime_error(FormatError("irgen", "不支持的一元运算符: " + op));
  }

  // ── 函数调用 ──────────────────────────────────────────────────────────────
  if (ctx->Ident() && ctx->L_PAREN()) {
    std::string callee_name = ctx->Ident()->getText();

    // 收集实参
    std::vector<ir::Value*> args;
    if (ctx->funcRParams()) {
      for (auto* exp : ctx->funcRParams()->exp()) {
        args.push_back(EvalExpr(*exp));
      }
    }

    // 模块内已知函数？
    ir::Function* callee = module_.GetFunction(callee_name);
    if (callee) {
      std::string ret_name =
          callee->IsVoidReturn() ? "" : module_.GetContext().NextTemp();
      auto* call =
          builder_.CreateCall(callee, std::move(args), ret_name);
      return static_cast<ir::Value*>(
          callee->IsVoidReturn() ? static_cast<ir::Value*>(
                                       builder_.CreateConstInt(0))
                                 : call);
    }

    // 外部函数
    EnsureExternalDecl(callee_name);
    // 获取返回类型
    std::shared_ptr<ir::Type> ret_type = ir::Type::GetInt32Type();
    for (const auto& decl : module_.GetExternalDecls()) {
      if (decl.name == callee_name) {
        ret_type = decl.ret_type;
        break;
      }
    }
    bool is_void = ret_type->IsVoid();
    std::string ret_name = is_void ? "" : module_.GetContext().NextTemp();
    auto* call = builder_.CreateCallExternal(callee_name, ret_type,
                                             std::move(args), ret_name);
    // void 调用返回 0 占位
    return static_cast<ir::Value*>(
        is_void ? static_cast<ir::Value*>(builder_.CreateConstInt(0)) : call);
  }

  // ── primaryExp ────────────────────────────────────────────────────────────
  if (ctx->primaryExp()) {
    return ctx->primaryExp()->accept(this);
  }

  throw std::runtime_error(FormatError("irgen", "非法一元表达式结构"));
}

// primaryExp : L_PAREN exp R_PAREN | lVar | number
std::any IRGenImpl::visitPrimaryExp(SysYParser::PrimaryExpContext* ctx) {
  if (!ctx) {
    throw std::runtime_error(FormatError("irgen", "非法基本表达式"));
  }
  if (ctx->exp()) {
    return ctx->exp()->accept(this);
  }
  if (ctx->lVar()) {
    return ctx->lVar()->accept(this);
  }
  if (ctx->number()) {
    return ctx->number()->accept(this);
  }
  throw std::runtime_error(FormatError("irgen", "primaryExp 结构非法"));
}

// EvalLVarAddr：计算 lVar 的地址（支持数组索引）
ir::Value* IRGenImpl::EvalLVarAddr(SysYParser::LVarContext* ctx) {
  if (!ctx || !ctx->Ident()) {
    throw std::runtime_error(FormatError("irgen", "非法变量引用"));
  }
  auto* decl = sema_.ResolveVarUse(ctx->Ident());
  if (!decl) {
    throw std::runtime_error(
        FormatError("irgen", "变量未绑定: " + ctx->Ident()->getText()));
  }

  // 查找存储槽位
  ir::Value* base = nullptr;
  std::vector<int> dims;

  auto it = storage_map_.find(decl);
  if (it != storage_map_.end()) {
    base = it->second;
    auto dit = array_dims_.find(decl);
    if (dit != array_dims_.end()) dims = dit->second;
  } else {
    auto git = global_storage_map_.find(decl);
    if (git == global_storage_map_.end()) {
      throw std::runtime_error(
          FormatError("irgen", "变量无存储槽位: " + ctx->Ident()->getText()));
    }
    base = git->second;
    auto gdit = global_array_dims_.find(decl);
    if (gdit != global_array_dims_.end()) dims = gdit->second;
  }

  // 无索引 → 返回基地址
  if (ctx->exp().empty()) return base;

  // 有索引 → 计算扁平化偏移
  auto indices = ctx->exp();

  // 对于数组参数（第一维为-1），允许索引数等于维度数
  bool is_array_param = !dims.empty() && dims[0] == -1;
  if (!is_array_param && indices.size() > dims.size()) {
    throw std::runtime_error(FormatError("irgen", "数组索引维度过多"));
  }

  ir::Value* offset = builder_.CreateConstInt(0);

  if (is_array_param) {
    // 数组参数：dims[0]=-1, dims[1..n]是已知维度
    // 索引：indices[0]对应第一维，indices[1]对应第二维...
    for (size_t i = 0; i < indices.size(); ++i) {
      ir::Value* idx = EvalExpr(*indices[i]);
      if (i == 0) {
        // 第一维：stride = dims[1] * dims[2] * ... (如果有的话)
        int stride = 1;
        for (size_t j = 1; j < dims.size(); ++j) {
          stride *= dims[j];
        }
        if (stride > 1) {
          ir::Value* scaled = builder_.CreateMul(
              idx, builder_.CreateConstInt(stride),
              module_.GetContext().NextTemp());
          offset = builder_.CreateAdd(offset, scaled,
                                      module_.GetContext().NextTemp());
        } else {
          offset = builder_.CreateAdd(offset, idx,
                                      module_.GetContext().NextTemp());
        }
      } else {
        // 后续维度
        int stride = 1;
        for (size_t j = i + 1; j < dims.size(); ++j) {
          stride *= dims[j];
        }
        ir::Value* scaled = builder_.CreateMul(
            idx, builder_.CreateConstInt(stride),
            module_.GetContext().NextTemp());
        offset = builder_.CreateAdd(offset, scaled,
                                    module_.GetContext().NextTemp());
      }
    }
  } else {
    // 普通数组：从最后一维开始计算
    int stride = 1;
    for (int i = (int)dims.size() - 1; i >= 0; --i) {
      stride = (i == (int)dims.size() - 1) ? 1 : stride * dims[i + 1];
      if (i < (int)indices.size()) {
        ir::Value* idx = EvalExpr(*indices[i]);
        ir::Value* scaled = builder_.CreateMul(
            idx, builder_.CreateConstInt(stride),
            module_.GetContext().NextTemp());
        offset = builder_.CreateAdd(offset, scaled,
                                    module_.GetContext().NextTemp());
      }
    }
  }

  return builder_.CreateGep(base, offset, module_.GetContext().NextTemp());
}

// lVar : Ident (L_BRAKT exp R_BRAKT)*
// 在表达式语境下：load 变量值（返回 i32）
std::any IRGenImpl::visitLVar(SysYParser::LVarContext* ctx) {
  if (!ctx || !ctx->Ident()) {
    throw std::runtime_error(FormatError("irgen", "非法变量引用"));
  }
  auto* decl = sema_.ResolveVarUse(ctx->Ident());
  if (!decl) {
    throw std::runtime_error(
        FormatError("irgen", "变量未绑定: " + ctx->Ident()->getText()));
  }

  // 标量常量（ConstDefContext 且无索引）
  if (auto* const_def = dynamic_cast<SysYParser::ConstDefContext*>(decl)) {
    if (ctx->exp().empty()) {
      // 先查局部
      auto it = storage_map_.find(const_def);
      if (it != storage_map_.end()) {
        if (auto* ci = dynamic_cast<ir::ConstantInt*>(it->second)) {
          return static_cast<ir::Value*>(ci);
        }
        if (auto* cf = dynamic_cast<ir::ConstantFloat*>(it->second)) {
          return static_cast<ir::Value*>(cf);
        }
      }
      // 再查全局
      auto git = global_storage_map_.find(const_def);
      if (git != global_storage_map_.end()) {
        if (auto* cf = dynamic_cast<ir::ConstantFloat*>(git->second)) {
          return static_cast<ir::Value*>(cf);
        }
      }
    }
  }

  // 通用路径：计算地址并 load
  ir::Value* addr = EvalLVarAddr(ctx);
  return static_cast<ir::Value*>(
      builder_.CreateLoad(addr, module_.GetContext().NextTemp()));
}

// number : IntConst | FloatConst
std::any IRGenImpl::visitNumber(SysYParser::NumberContext* ctx) {
  if (!ctx) {
    throw std::runtime_error(FormatError("irgen", "非法数字"));
  }
  if (ctx->IntConst()) {
    std::string text = ctx->IntConst()->getText();
    int val = 0;
    try {
      val = std::stoi(text, nullptr, 0);
    } catch (...) {
      throw std::runtime_error(
          FormatError("irgen", "整数字面量解析失败: " + text));
    }
    return static_cast<ir::Value*>(builder_.CreateConstInt(val));
  }
  if (ctx->FloatConst()) {
    std::string text = ctx->FloatConst()->getText();
    float val = 0.0f;
    try {
      val = std::stof(text);
    } catch (...) {
      throw std::runtime_error(
          FormatError("irgen", "浮点字面量解析失败: " + text));
    }
    return static_cast<ir::Value*>(builder_.CreateConstFloat(val));
  }
  throw std::runtime_error(FormatError("irgen", "非法数字节点"));
}

// ─── 条件表达式访问器（返回 ir::Value*，i1） ──────────────────────────────────

std::any IRGenImpl::visitCond(SysYParser::CondContext* ctx) {
  if (!ctx || !ctx->lOrExp()) {
    throw std::runtime_error(FormatError("irgen", "非法条件"));
  }
  return ctx->lOrExp()->accept(this);
}

// lOrExp : lAndExp ('||' lAndExp)*
std::any IRGenImpl::visitLOrExp(SysYParser::LOrExpContext* ctx) {
  if (!ctx) throw std::runtime_error(FormatError("irgen", "非法 lOrExp"));
  auto ands = ctx->lAndExp();
  if (ands.empty()) throw std::runtime_error(FormatError("irgen", "lOrExp 空"));

  ir::Value* result = std::any_cast<ir::Value*>(ands[0]->accept(this));
  result = ToI1(result);

  for (size_t i = 1; i < ands.size(); ++i) {
    // 检查当前块是否已终结
    if (builder_.GetInsertBlock() && builder_.GetInsertBlock()->HasTerminator()) {
      break;
    }

    // 短路：result || rhs
    auto* res_slot = builder_.CreateAllocaI32(module_.GetContext().NextTemp());
    ir::Value* res_ext = ToI32(result);
    builder_.CreateStore(res_ext, res_slot);

    ir::BasicBlock* rhs_bb = func_->CreateBlock(module_.GetContext().NextTemp() + ".or.rhs");
    ir::BasicBlock* end_bb = func_->CreateBlock(module_.GetContext().NextTemp() + ".or.end");
    builder_.CreateCondBr(result, end_bb, rhs_bb);

    builder_.SetInsertPoint(rhs_bb);
    ir::Value* rhs = std::any_cast<ir::Value*>(ands[i]->accept(this));
    rhs = ToI32(ToI1(rhs));
    if (!builder_.GetInsertBlock()->HasTerminator()) {
      builder_.CreateStore(rhs, res_slot);
      builder_.CreateBr(end_bb);
    }

    builder_.SetInsertPoint(end_bb);
    result = ToI1(builder_.CreateLoad(res_slot, module_.GetContext().NextTemp()));
  }
  return static_cast<ir::Value*>(result);
}

// lAndExp : eqExp ('&&' eqExp)*
std::any IRGenImpl::visitLAndExp(SysYParser::LAndExpContext* ctx) {
  if (!ctx) throw std::runtime_error(FormatError("irgen", "非法 lAndExp"));
  auto eqs = ctx->eqExp();
  if (eqs.empty()) throw std::runtime_error(FormatError("irgen", "lAndExp 空"));

  ir::Value* result = std::any_cast<ir::Value*>(eqs[0]->accept(this));
  result = ToI1(result);

  for (size_t i = 1; i < eqs.size(); ++i) {
    // 检查当前块是否已终结
    if (builder_.GetInsertBlock() && builder_.GetInsertBlock()->HasTerminator()) {
      break;
    }

    auto* res_slot = builder_.CreateAllocaI32(module_.GetContext().NextTemp());
    ir::Value* res_ext = ToI32(result);
    builder_.CreateStore(res_ext, res_slot);

    ir::BasicBlock* rhs_bb = func_->CreateBlock(module_.GetContext().NextTemp() + ".and.rhs");
    ir::BasicBlock* end_bb = func_->CreateBlock(module_.GetContext().NextTemp() + ".and.end");
    builder_.CreateCondBr(result, rhs_bb, end_bb);

    builder_.SetInsertPoint(rhs_bb);
    ir::Value* rhs = std::any_cast<ir::Value*>(eqs[i]->accept(this));
    rhs = ToI32(ToI1(rhs));
    if (!builder_.GetInsertBlock()->HasTerminator()) {
      builder_.CreateStore(rhs, res_slot);
      builder_.CreateBr(end_bb);
    }

    builder_.SetInsertPoint(end_bb);
    result = ToI1(builder_.CreateLoad(res_slot, module_.GetContext().NextTemp()));
  }
  return static_cast<ir::Value*>(result);
}

// eqExp : relExp (EqOp relExp)*
std::any IRGenImpl::visitEqExp(SysYParser::EqExpContext* ctx) {
  if (!ctx) throw std::runtime_error(FormatError("irgen", "非法 eqExp"));
  auto rels = ctx->relExp();
  if (rels.empty()) throw std::runtime_error(FormatError("irgen", "eqExp 空"));

  ir::Value* result = std::any_cast<ir::Value*>(rels[0]->accept(this));
  auto ops = ctx->EqOp();

  for (size_t i = 0; i < ops.size(); ++i) {
    ir::Value* rhs = std::any_cast<ir::Value*>(rels[i + 1]->accept(this));
    ir::Value* lhs = result;
    ImplicitConvert(lhs, rhs);
    std::string op = ops[i]->getText();
    if (lhs->IsFloat32()) {
      ir::FCmpPredicate pred = (op == "==") ? ir::FCmpPredicate::OEQ : ir::FCmpPredicate::ONE;
      result = builder_.CreateFCmp(pred, lhs, rhs, module_.GetContext().NextTemp());
    } else {
      lhs = ToI32(lhs);
      rhs = ToI32(rhs);
      ir::ICmpPredicate pred = (op == "==") ? ir::ICmpPredicate::EQ : ir::ICmpPredicate::NE;
      result = builder_.CreateICmp(pred, lhs, rhs, module_.GetContext().NextTemp());
    }
  }
  return static_cast<ir::Value*>(result);
}

// relExp : addExp (RelOp addExp)*
std::any IRGenImpl::visitRelExp(SysYParser::RelExpContext* ctx) {
  if (!ctx) throw std::runtime_error(FormatError("irgen", "非法 relExp"));
  auto adds = ctx->addExp();
  if (adds.empty()) throw std::runtime_error(FormatError("irgen", "relExp 空"));

  ir::Value* result = std::any_cast<ir::Value*>(adds[0]->accept(this));
  auto ops = ctx->RelOp();

  for (size_t i = 0; i < ops.size(); ++i) {
    ir::Value* rhs = std::any_cast<ir::Value*>(adds[i + 1]->accept(this));
    ir::Value* lhs = result;
    ImplicitConvert(lhs, rhs);
    std::string op = ops[i]->getText();
    if (lhs->IsFloat32()) {
      ir::FCmpPredicate pred;
      if (op == "<")       pred = ir::FCmpPredicate::OLT;
      else if (op == ">")  pred = ir::FCmpPredicate::OGT;
      else if (op == "<=") pred = ir::FCmpPredicate::OLE;
      else                 pred = ir::FCmpPredicate::OGE;
      result = builder_.CreateFCmp(pred, lhs, rhs, module_.GetContext().NextTemp());
    } else {
      lhs = ToI32(lhs);
      rhs = ToI32(rhs);
      ir::ICmpPredicate pred;
      if (op == "<")       pred = ir::ICmpPredicate::SLT;
      else if (op == ">")  pred = ir::ICmpPredicate::SGT;
      else if (op == "<=") pred = ir::ICmpPredicate::SLE;
      else                 pred = ir::ICmpPredicate::SGE;
      result = builder_.CreateICmp(pred, lhs, rhs, module_.GetContext().NextTemp());
    }
  }
  return static_cast<ir::Value*>(result);
}