如果有副作用，可以优化功能吗? [英] Can functions be optimized away if they have side effects?

问题描述

我想在主线程上初始化一些静态数据.

I want to initialize some static data on the main thread.

int32_t GetFoo(ptime t)
{
   static HugeBarData data;
   return data.Baz(t);
}

int main()
{
    GetFoo(); // Avoid data race on static field. 
              // But will it be optimized away as unnecessary?

    // Spawn threads. Call 'GetFoo' on the threads.
}

如果编译器可能决定删除它，我怎么能迫使它呆在那里?

If the complier may decide to remove it, how can I force it to stay there?

推荐答案

C ++编译器可以优化的唯一副作用是不必要的构造函数调用，尤其是复制构造函数.

The only side-effecting functions that a C++ compiler can optimize away are unnecessary constructor calls, particularly copy constructors.

Cf 在什么条件下C ++可以优化构造函数调用?

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