#15578: Honour INLINE pragmas on 0-arity bindings -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #15519 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): OK here's a better patch {{{ diff --git a/compiler/coreSyn/CoreUnfold.hs b/compiler/coreSyn/CoreUnfold.hs index 68e7290..fe2ae62 100644 --- a/compiler/coreSyn/CoreUnfold.hs +++ b/compiler/coreSyn/CoreUnfold.hs @@ -159,7 +159,8 @@ mkInlineUnfoldingWithArity arity expr guide = UnfWhen { ug_arity = arity , ug_unsat_ok = needSaturated , ug_boring_ok = boring_ok } - boring_ok = inlineBoringOk expr' + boring_ok | arity == 0 = True + | otherwise = inlineBoringOk expr' mkInlinableUnfolding :: DynFlags -> CoreExpr -> Unfolding mkInlinableUnfolding dflags expr diff --git a/compiler/simplCore/Simplify.hs b/compiler/simplCore/Simplify.hs index c8870c9..b0f6455 100644 --- a/compiler/simplCore/Simplify.hs +++ b/compiler/simplCore/Simplify.hs @@ -3402,14 +3402,18 @@ simplStableUnfolding env top_lvl mb_cont id unf rhs_ty Just cont -> simplJoinRhs unf_env id expr cont Nothing -> simplExprC unf_env expr (mkBoringStop rhs_ty) ; case guide of - UnfWhen { ug_arity = arity, ug_unsat_ok = sat_ok } -- Happens for INLINE things + UnfWhen { ug_arity = arity, ug_unsat_ok = sat_ok + , ug_boring_ok = boring_ok } + -- This branch happens for INLINE things -> let guide' = UnfWhen { ug_arity = arity, ug_unsat_ok = sat_ok - , ug_boring_ok = inlineBoringOk expr' } + , ug_boring_ok = boring_ok || inlineBoringOk expr' } -- Refresh the boring-ok flag, in case expr' -- has got small. This happens, notably in the inlinings -- for dfuns for single-method classes; see -- Note [Single-method classes] in TcInstDcls. -- A test case is Trac #4138 + -- But don't forget a boring_ok of True; e.g. see the + -- way it is set in calcUnfoldingGuidanceWithArity in return (mkCoreUnfolding src is_top_lvl expr' guide') -- See Note [Top-level flag on inline rules] in CoreUnfold }}} I'd forgotten about the bit in `Simplify`. Moreover, you do need {{{ test3 = oneShot (runTokenParser testGrammar1) }}} Then I think we get good perf. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15578#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler