Remove obselete code for update-in-place (which we no longer do)

[ghc-hetmet.git] / compiler / simplCore / SimplUtils.lhs

diff --git a/compiler/simplCore/SimplUtils.lhs b/compiler/simplCore/SimplUtils.lhs
index cff659d..6ce29a2 100644 (file)
--- a/compiler/simplCore/SimplUtils.lhs
+++ b/compiler/simplCore/SimplUtils.lhs
@@ -95,10 +95,8 @@ data SimplCont
        Bool            -- True <=> There is something interesting about
                        --          the context, and hence the inliner
                        --          should be a bit keener (see interestingCallContext)
-                       -- Two cases:
-                       -- (a) This is the RHS of a thunk whose type suggests
-                       --     that update-in-place would be possible
-                       -- (b) This is an argument of a function that has RULES
+                       -- Specifically:
+                       --     This is an argument of a function that has RULES
                        --     Inlining the call might allow the rule to fire
 
   | CoerceIt           -- C `cast` co
@@ -156,10 +154,10 @@ mkBoringStop :: OutType -> SimplCont
 mkBoringStop ty = Stop ty AnArg False
 
 mkLazyArgStop :: OutType -> Bool -> SimplCont
-mkLazyArgStop ty has_rules = Stop ty AnArg (canUpdateInPlace ty || has_rules)
+mkLazyArgStop ty has_rules = Stop ty AnArg has_rules
 
 mkRhsStop :: OutType -> SimplCont
-mkRhsStop ty = Stop ty AnRhs (canUpdateInPlace ty)
+mkRhsStop ty = Stop ty AnRhs False
 
 -------------------
 contIsRhsOrArg (Stop {})                = True
@@ -400,27 +398,6 @@ interestingArgContext fn call_cont
     go (StrictBind {})       = False   -- ??
     go (CoerceIt _ c)        = go c
     go (Stop _ _ interesting) = interesting
-
--------------------
-canUpdateInPlace :: Type -> Bool
--- Consider   let x = <wurble> in ...
--- If <wurble> returns an explicit constructor, we might be able
--- to do update in place.  So we treat even a thunk RHS context
--- as interesting if update in place is possible.  We approximate
--- this by seeing if the type has a single constructor with a
--- small arity.  But arity zero isn't good -- we share the single copy
--- for that case, so no point in sharing.
-
-canUpdateInPlace ty 
-  | not opt_UF_UpdateInPlace = False
-  | otherwise
-  = case splitTyConApp_maybe ty of 
-       Nothing         -> False 
-       Just (tycon, _) -> case tyConDataCons_maybe tycon of
-                               Just [dc]  -> arity == 1 || arity == 2
-                                          where
-                                             arity = dataConRepArity dc
-                               other -> False
 \end{code}