基于BDD的谓词分析与优化

Predicate Analysis and Optimization Based on BDD

为对带谓词的数据流进行准确而有效的分析,首先介绍了John W.Sias等人提出的一种基于二进制决策图(BDD)的谓词分析系统(PAS);然后在其基础上,提出了结合芯片自身体系结构特点的谓词优化算法。将PAS及优化算法在学院研制的FT_D4芯片的编译器上实现,实验结果表明,这种基于BDD的谓词分析与优化方法简化了程序控制结构,减少了对谓词寄存器的使用,缩短了代码执行时间,性能获得了较大的提高。

In order to analyze predicate code accurately,this paper first introduces Predicate Analysis System based on binary decision diagrams,which is put forward by John W.Sias etc.And then a predicate optimization algorithm is presented,incorporating characteristics of certain chips＇ architecture.PAS and the optimization algorithm have been implemented in the compiler of YHFT_D4 chip developed by authors＂ college.Experiment results show that program decision structure is simplified,the number of used predicate registers is reduced,the code execution time is shortened, and the performance is imoroved greatly.