编译器中激进蝴蝶优化方法的研究与实现

编译优化技术的目的是挖掘程序中的优化空间，提高程序编译或运行效率，无效代码删除优化是被广泛使用的编译优化技术之一，它旨在删除程序中不可达的代码，以提升程序的执行效率。许多应用程序的执行路径往往与运行时的输入参数值相关，并且在一些分支路径上与运行时参数值相结合，可能存在无效代码，通过现有的无效代码删除优化，很难做出优化处理。为此，提出一种依赖数据流分析的激进蝴蝶优化方法，利用SSA中间表示，根据动态运行时的参数可能值，自动为程序生成代码形状类似蝴蝶（butterfly）的分支代码，使编译器在程序编译阶段为相关优化提供可行的优化依据。最后通过实验验证了该方法的有效性和可行性。

An aggressive butterfly optimization method in compiler

The purpose of compilation optimization technology is to explore the optimization space in the program and improve the efficiency of program compilation or operation. Dead code elimination optimization is one of the widely used compilation optimization technologies. It aims to delete the unreachable codes in the program to improve the execution efficiency of the programs. In many applications, the execution path is often related to the input parameter values at runtime, and some branch paths are combined with the runtime parameter values. There may be dead codes. It is difficult to deal with these dead codes through the existing dead code elimination optimization. To this end, this paper proposes an aggressive butterfly optimization method that relies on data flow analysis. According to the possible values of dynamic runtime parameters, the method uses SSA intermediate representation to automatically generate the branch code similar to butterfly shape for the program. At the stage of program compilation in compiler, it provides feasible optimization basis for related optimization. Finally, the effectiveness and feasibility of this method are verified through experiments.