{"title":"OOElala:用于编译器优化的基于求值顺序的别名分析","authors":"Ankush Phulia, Vaibhav Bhagee, Sorav Bansal","doi":"10.1145/3385412.3385962","DOIUrl":null,"url":null,"abstract":"In C, the order of evaluation of expressions is unspecified; further for expressions that do not involve function calls, C semantics ensure that there cannot be a data race between two evaluations that can proceed in either order (or concurrently). We explore the optimization opportunity enabled by these non-deterministic expression evaluation semantics in C, and provide a sound compile-time alias analysis to realize the same. Our algorithm is implemented as a part of the Clang/LLVM infrastructure, in a tool called OOElala. Our experimental results demonstrate that the untapped optimization opportunity is significant: code patterns that enable such optimizations are common; the enabled transformations can range from vectorization to improved instruction selection and register allocation; and the resulting speedups can be as high as 2.6x on already-optimized code.","PeriodicalId":20580,"journal":{"name":"Proceedings of the 41st ACM SIGPLAN Conference on Programming Language Design and Implementation","volume":"42 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2020-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"3","resultStr":"{\"title\":\"OOElala: order-of-evaluation based alias analysis for compiler optimization\",\"authors\":\"Ankush Phulia, Vaibhav Bhagee, Sorav Bansal\",\"doi\":\"10.1145/3385412.3385962\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"In C, the order of evaluation of expressions is unspecified; further for expressions that do not involve function calls, C semantics ensure that there cannot be a data race between two evaluations that can proceed in either order (or concurrently). We explore the optimization opportunity enabled by these non-deterministic expression evaluation semantics in C, and provide a sound compile-time alias analysis to realize the same. Our algorithm is implemented as a part of the Clang/LLVM infrastructure, in a tool called OOElala. Our experimental results demonstrate that the untapped optimization opportunity is significant: code patterns that enable such optimizations are common; the enabled transformations can range from vectorization to improved instruction selection and register allocation; and the resulting speedups can be as high as 2.6x on already-optimized code.\",\"PeriodicalId\":20580,\"journal\":{\"name\":\"Proceedings of the 41st ACM SIGPLAN Conference on Programming Language Design and Implementation\",\"volume\":\"42 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2020-06-06\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"3\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Proceedings of the 41st ACM SIGPLAN Conference on Programming Language Design and Implementation\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1145/3385412.3385962\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Proceedings of the 41st ACM SIGPLAN Conference on Programming Language Design and Implementation","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1145/3385412.3385962","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
OOElala: order-of-evaluation based alias analysis for compiler optimization
In C, the order of evaluation of expressions is unspecified; further for expressions that do not involve function calls, C semantics ensure that there cannot be a data race between two evaluations that can proceed in either order (or concurrently). We explore the optimization opportunity enabled by these non-deterministic expression evaluation semantics in C, and provide a sound compile-time alias analysis to realize the same. Our algorithm is implemented as a part of the Clang/LLVM infrastructure, in a tool called OOElala. Our experimental results demonstrate that the untapped optimization opportunity is significant: code patterns that enable such optimizations are common; the enabled transformations can range from vectorization to improved instruction selection and register allocation; and the resulting speedups can be as high as 2.6x on already-optimized code.