The FeedBack Compiler

The feedback compiler provides information from the backend of a compiler. This information is useful for beginning programmers, experienced programmers, teaching programming, and teaching compiler construction. Activities that benefit from feedback include debugging optimized code, learning effective programming techniques, and porting programs to new architectures. Common subexpression and loop skewing are considered as example optimizations for which backend feedback is useful. Results of an experiment involving the feedback compiler are presented. 1 Introduction A compiler is divided into two ends: a front-end--- composed of a lexical analyzer (or parser) and a semantic analyzer---and a back-end---composed of an (optional) code optimizer and a (machine) code generator. Modern front-ends provide a programmer with a wealth of information regarding their operation (usually in the form of syntactic and semantic warning and error messages). In contrast, little, if supported by Natio..