Method BuildVecAdd

cpp/src/gandiva/engine_llvm_test.cc:31–100

class TestEngine : public ::testing::Test {
 protected:
  std::string BuildVecAdd(Engine* gdv_engine) {
    auto types = gdv_engine->types();
    llvm::IRBuilder<>* builder = gdv_engine->ir_builder();
    llvm::LLVMContext* context = gdv_engine->context();

    // Create fn prototype :
    //   int64_t add_longs(int64_t *elements, int32_t nelements)
    std::vector<llvm::Type*> arguments;
    arguments.push_back(types->i64_ptr_type());
    arguments.push_back(types->i32_type());
    llvm::FunctionType* prototype =
        llvm::FunctionType::get(types->i64_type(), arguments, false /*isVarArg*/);

    // Create fn
    std::string func_name = "add_longs_test_expr";
    gdv_engine->AddFunctionToCompile(func_name);
    llvm::Function* fn = llvm::Function::Create(
        prototype, llvm::GlobalValue::ExternalLinkage, func_name, gdv_engine->module());
    assert(fn != nullptr);

    // Name the arguments
    llvm::Function::arg_iterator args = fn->arg_begin();
    llvm::Value* arg_elements = &*args;
    arg_elements->setName("elements");
    ++args;
    llvm::Value* arg_nelements = &*args;
    arg_nelements->setName("nelements");
    ++args;

    llvm::BasicBlock* loop_entry = llvm::BasicBlock::Create(*context, "entry", fn);
    llvm::BasicBlock* loop_body = llvm::BasicBlock::Create(*context, "loop", fn);
    llvm::BasicBlock* loop_exit = llvm::BasicBlock::Create(*context, "exit", fn);

    // Loop entry
    builder->SetInsertPoint(loop_entry);
    builder->CreateBr(loop_body);

    // Loop body
    builder->SetInsertPoint(loop_body);

    llvm::PHINode* loop_var = builder->CreatePHI(types->i32_type(), 2, "loop_var");
    llvm::PHINode* sum = builder->CreatePHI(types->i64_type(), 2, "sum");

    loop_var->addIncoming(types->i32_constant(0), loop_entry);
    sum->addIncoming(types->i64_constant(0), loop_entry);

    // setup loop PHI
    llvm::Value* loop_update =
        builder->CreateAdd(loop_var, types->i32_constant(1), "loop_var+1");
    loop_var->addIncoming(loop_update, loop_body);

    // get the current value
    llvm::Value* offset =
        builder->CreateGEP(types->i64_type(), arg_elements, loop_var, "offset");
    llvm::Value* current_value = builder->CreateLoad(types->i64_type(), offset, "value");

    // setup sum PHI
    llvm::Value* sum_update = builder->CreateAdd(sum, current_value, "sum+ith");