#9136: Constant folding in Core could be better ------------------------------+-------------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Runtime performance bug Unknown/Multiple | Test Case: Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: | ------------------------------+-------------------------------------------- Constant folding in Core is still a bit feeble. For example, when staring at the code for `nofib/shootout/k-nucleotide` I saw this expression: {{{ (x +# 8) -# 1 }}} which would be relatively easy to optimise. The difficulty is knowing where to stop. What about `(8 +# x) -# 1`? Anyway, this ticket is to record the issue. Currently constant folding is done by the built-in RULES in `compiler/prelude/PrelRules`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9136 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler