#12893: Profiling defeats stream fusion when using vector library -------------------------------------+------------------------------------- Reporter: newhoggy | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: stream-fusion | profiling Operating System: MacOS X | Architecture: x86_64 Type of failure: Runtime | (amd64) performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by guaraqe): I think the problem that the OP is reporting is that there are no cost centers in the program, yet no optimization is done. There are no manual `SCC`s and compilation is done with `-fno-prof-count-entries -fno-prof- cafs -fno-prof-auto -O2`, so we would expect that there would be no barriers for optimization. This can be wrong if for some reason the GHC flags are not passed to the `vector` library, and it is still being compiled with automatic cost centers, which would indeed block fusion. If that is the case, it would be nice to have a way to pass these flags all the way down. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12893#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler