
#16372: GHC can't constant fold even basic power (^) applications for Int (and others?) -------------------------------------+------------------------------------- Reporter: Fuuzetsu | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.3 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: | -------------------------------------+------------------------------------- Description changed by Fuuzetsu: Old description:
{{{#!hs [nix-shell:/tmp]$ ghc -O2 -fforce-recomp -ddump-simpl S.hs 2>&1 | tail [GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=False, ConLike=False, WorkFree=False, Expandable=False, Guidance=IF_ARGS [] 50 20}] foo = case GHC.Real.$wf1 2# 1# of ww2_a2zt { __DEFAULT -> GHC.Types.I# ww2_a2zt }
[nix-shell:/tmp]$ cat S.hs module S (fuck) where foo :: Int foo = (2 :: Int) ^ (1 :: Int) }}}
This seems like a fairly strange thing to not optimise when constants are known on both sides. I'm complaining about Int for this particular ticket.
New description: {{{#!hs [nix-shell:/tmp]$ ghc -O2 -fforce-recomp -ddump-simpl S.hs 2>&1 | tail [GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=False, ConLike=False, WorkFree=False, Expandable=False, Guidance=IF_ARGS [] 50 20}] foo = case GHC.Real.$wf1 2# 1# of ww2_a2zt { __DEFAULT -> GHC.Types.I# ww2_a2zt } [nix-shell:/tmp]$ cat S.hs module S (foo) where foo :: Int foo = (2 :: Int) ^ (1 :: Int) }}} This seems like a fairly strange thing to not optimise when constants are known on both sides. I'm complaining about Int for this particular ticket. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16372#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler