Optimizing Eden by Program Transformation

Eden is a parallel extension of Haskell allowing the programmer to explicitly specify which expressions must be evaluated as parallel processes. Eden is implemented by modifying the Glasgow Haskell Compiler (GHC). This decision has saved a lot of work but has also produced some drawbacks: Some optimizing transformations done by GHC are not convenient for Eden, either because they spoil its semantics or because they negatively aaect its eeciency. The paper explains how to circumvent these drawbacks and also how to add our own optimizing analysis and transformation steps in order to generate a (correct and) better parallel code.