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Diffstat (limited to 'ghc/compiler/stranal/DmdAnal.lhs')
| -rw-r--r-- | ghc/compiler/stranal/DmdAnal.lhs | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/ghc/compiler/stranal/DmdAnal.lhs b/ghc/compiler/stranal/DmdAnal.lhs index d0ac19e1de..714d8ed7dd 100644 --- a/ghc/compiler/stranal/DmdAnal.lhs +++ b/ghc/compiler/stranal/DmdAnal.lhs @@ -919,6 +919,19 @@ lub (Seq k1 ds1) (Seq k2 ds2) lub d1@(Seq _ _) d2 = d2 `lub` d1 + +defer :: Demand -> Demand +-- Computes (Abs `lub` d) +-- For the Bot case consider +-- f x y = if ... then x else error x +-- Then for y we get Abs `lub` Bot, and we really +-- want Abs overall +defer Bot = Abs +defer Abs = Abs +defer (Seq Keep ds) = Lazy +defer (Seq _ ds) = Seq Defer ds +defer d = Lazy + --------------- both :: Demand -> Demand -> Demand |