基于路径信息的谓词关系分析

Predicate Analysis Based on Path Information

谓词执行技术能够将多个基本块合并为一个超块 ,扩大指令调度范围 ,开发更多的指令级并行 .但它也给编译优化带来一些新问题 ,使得传统的编译器在进行指令调度或寄存器分配等优化工作时往往只能得到保守的结果 .受所用谓词表示方法的限制 ,目前的谓词关系分析方法必须首先重构控制流信息 ,这就影响了编译优化的效果和效率 .本文提出了一种基于路径编码的谓词表示方法 ,将谓词定义信息转换为等价的域编码 ,并以此为基础实现了一个全局谓词关系分析子系统 .模拟结果表明 ,该子系统能够准确高效地实现全局谓词关系分析 ,在保证编译效率的同时 。

Several basic blocks could be merged into a hyperblock in predicated execution so that instructions could be scheduled on a larger scope and more instruction level parallelism could be extracted. But it also brings some new challenges to traditional optimizers without predicate analysis, which can only yield conservative results. But unfortunately, limited by predicate representations, current methods need reconstructing control flow information before analyzing predicate relationships, which limits the effectiveness and efficiency of optimization. A new representation based on path information is proposed, which can convert predicate definitions into equivalent domain codes. And a global predicate relationship query system is constructed based on it. Experiment results indicated that precise and efficient global predicate analysis could be achieved with this system and the performance of optimized codes can also be improved with little impact on compilation efficiency.