#13570: CoreFVs patch makes n-body slower -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by hsyl20): With the floating-in of the array-indexing primop, instead of having the following order: {{{ 1) A <- load from address @XXX 2) compute several things (sqrt,mul,div,sub,add) independent of A 3) store (A - ..) at address @XXX }}} We have this order: 2, 1, 3. As this is n-body, could it be a prefetching issue? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13570#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler