#8763: forM_ [1..N] does not get fused (10 times slower than go function) -------------------------------------+------------------------------------- Reporter: nh2 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by George): With 7.10.1 I see a factor of 2 difference in performance: benchmarking matmultForM_ time 10.90 μs (10.89 μs .. 10.91 μs) 1.000 R² (1.000 R² .. 1.000 R²) mean 10.89 μs (10.89 μs .. 10.91 μs) std dev 32.72 ns (18.98 ns .. 65.42 ns) benchmarking matmultLoop time 5.404 μs (5.387 μs .. 5.419 μs) 1.000 R² (1.000 R² .. 1.000 R²) mean 5.409 μs (5.398 μs .. 5.420 μs) std dev 37.99 ns (33.64 ns .. 44.26 ns) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8763#comment:18 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler