#12656: ghc floats out constant despite -fno-cse -------------------------------------+------------------------------------- Reporter: nh2 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bitonic): Actually I spoke too soon: this doesn't work even with `NOINLINE`! {{{ $ cat weird-float.hs import qualified Data.Vector as V import qualified Data.Vector.Mutable as VM main :: IO () main = do foo 100000 foo 100000 let f = foo 100000 in f >> f {-# NOINLINE foo #-} foo :: Int -> IO () foo n = do indexVector <- V.unsafeThaw $ V.generate n id x <- VM.read indexVector 5 VM.write indexVector 5 (x * x) print x $ stack exec --resolver lts-7 --package vector -- ghc -fforce-recomp -package vector -O0 -fno-full-laziness -fno-cse weird-float.hs -o weird- float-lts-7 Run from outside a project, using implicit global project config Using resolver: lts-7 specified on command line Selected resolver: lts-7.2 [1 of 1] Compiling Main ( weird-float.hs, weird-float.o ) Linking weird-float-lts-7 ... $ ./weird-float-lts-7 5 5 5 25 $ stack exec --resolver lts-7 --package vector -- ghc --version Run from outside a project, using implicit global project config Using resolver: lts-7 specified on command line Selected resolver: lts-7.2 The Glorious Glasgow Haskell Compilation System, version 8.0.1 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12656#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler