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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2021-05-27 12:02:45 +0100 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2021-06-05 19:23:46 -0400 |
| commit | 52a524f7c8c5701708a007a5946c27914703d045 (patch) | |
| tree | 63e5417205788aa800e06ef679f96ca29a3586aa /compiler/GHC/Stg/Unarise.hs | |
| parent | ea9a4ef69a382cf3cee28b78eca390a6a06c6965 (diff) | |
| download | haskell-52a524f7c8c5701708a007a5946c27914703d045.tar.gz | |
Re-do rubbish literals
As #19882 pointed out, we were simply doing rubbish literals wrong.
(I'll refrain from explaining the wrong-ness here -- see the ticket.)
This patch fixes it by adding a Type (of kind RuntimeRep) as field of
LitRubbish, rather than [PrimRep].
The Note [Rubbish literals] in GHC.Types.Literal explains the details.
Diffstat (limited to 'compiler/GHC/Stg/Unarise.hs')
| -rw-r--r-- | compiler/GHC/Stg/Unarise.hs | 23 |
1 files changed, 11 insertions, 12 deletions
diff --git a/compiler/GHC/Stg/Unarise.hs b/compiler/GHC/Stg/Unarise.hs index 6b41063f9b..b3ae7957d9 100644 --- a/compiler/GHC/Stg/Unarise.hs +++ b/compiler/GHC/Stg/Unarise.hs @@ -231,7 +231,7 @@ STG programs after unarisation have these invariants: This means that it's safe to wrap `StgArg`s of DataCon applications with `GHC.StgToCmm.Env.NonVoid`, for example. - * Similar to unboxed tuples, Note [Rubbish values] of TupleRep may only + * Similar to unboxed tuples, Note [Rubbish literals] of TupleRep may only appear in return position. * Alt binders (binders in patterns) are always non-void. @@ -390,7 +390,7 @@ unariseExpr rho (StgCase scrut bndr alt_ty alts) , Just args' <- unariseMulti_maybe rho dc args ty_args = elimCase rho args' bndr alt_ty alts - -- See (3) of Note [Rubbish values] in GHC.Types.Literal + -- See (3) of Note [Rubbish literals] in GHC.Types.Literal | StgLit lit <- scrut , Just args' <- unariseRubbish_maybe lit = elimCase rho args' bndr alt_ty alts @@ -427,19 +427,18 @@ unariseMulti_maybe rho dc args ty_args -- Doesn't return void args. unariseRubbish_maybe :: Literal -> Maybe [OutStgArg] -unariseRubbish_maybe lit - | LitRubbish preps <- lit - , [prep] <- preps +unariseRubbish_maybe (LitRubbish rep) + | [prep] <- preps , not (isVoidRep prep) - -- Single, non-void PrimRep. Nothing to do! - = Nothing + = Nothing -- Single, non-void PrimRep. Nothing to do! - | LitRubbish preps <- lit - -- Multiple reps, possibly with VoidRep. Eliminate! - = Just [ StgLitArg (LitRubbish [prep]) | prep <- preps, not (isVoidRep prep) ] + | otherwise -- Multiple reps, possibly with VoidRep. Eliminate via elimCase + = Just [ StgLitArg (LitRubbish (primRepToType prep)) + | prep <- preps, not (isVoidRep prep) ] + where + preps = runtimeRepPrimRep (text "unariseRubbish_maybe") rep - | otherwise - = Nothing +unariseRubbish_maybe _ = Nothing -------------------------------------------------------------------------------- |