X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FsimplCore%2FSimplEnv.lhs;h=3832f547de2c019d184976fd877547946e263dac;hb=96cb07b5940f98f35ac292e40d0129db5d3748ce;hp=c9fb4fbb8ba23d5d9471a535c0498c71fe0609e1;hpb=6f074a37a1546391632863898da3c32bbb7995df;p=ghc-hetmet.git

diff --git a/compiler/simplCore/SimplEnv.lhs b/compiler/simplCore/SimplEnv.lhs
index c9fb4fb..3832f54 100644
--- a/compiler/simplCore/SimplEnv.lhs
+++ b/compiler/simplCore/SimplEnv.lhs
@@ -9,8 +9,6 @@ module SimplEnv (
 	OutId, OutTyVar, OutBind, OutExpr, OutAlt, OutArg, OutType, OutBndr,
         InCoercion, OutCoercion,
 
-	isStrictBndr,
-
 	-- The simplifier mode
 	setMode, getMode, 
 
@@ -92,13 +90,6 @@ type OutAlt	 = CoreAlt
 type OutArg	 = CoreArg
 \end{code}
 
-\begin{code}
-isStrictBndr :: Id -> Bool
-isStrictBndr bndr
-  = ASSERT2( isId bndr, ppr bndr )
-    isStrictDmd (idNewDemandInfo bndr) || isStrictType (idType bndr)
-\end{code}
-
 %************************************************************************
 %*									*
 \subsubsection{The @SimplEnv@ type}
@@ -364,7 +355,7 @@ andFF FltLifted  flt	    = flt
 classifyFF :: CoreBind -> FloatFlag
 classifyFF (Rec _) = FltLifted
 classifyFF (NonRec bndr rhs) 
-  | not (isStrictBndr bndr)  = FltLifted
+  | not (isStrictId bndr)    = FltLifted
   | exprOkForSpeculation rhs = FltOkSpec
   | otherwise		     = FltCareful
 
@@ -608,8 +599,12 @@ substLetIdBndr :: SimplEnv -> InBndr 	-- Env and binder to transform
 	       -> (SimplEnv, OutBndr)
 -- C.f. substIdBndr above
 -- Clone Id if necessary, substitute its type
--- Return an Id with completely zapped IdInfo
+-- Return an Id with its fragile info zapped
+--	namely, any info that depends on free variables
 -- 	[addLetIdInfo, below, will restore its IdInfo]
+--	We want to retain robust info, especially arity and demand info,
+--	so that they are available to occurrences that occur in an
+--	earlier binding of a letrec
 -- Augment the subtitution 
 --	if the unique changed, *or* 
 --	if there's interesting occurrence info
@@ -620,7 +615,10 @@ substLetIdBndr env@(SimplEnv { seInScope = in_scope, seIdSubst = id_subst }) old
   where
     id1	   = uniqAway in_scope old_id
     id2    = substIdType env id1
-    new_id = setIdInfo id2 vanillaIdInfo
+
+    -- We want to get rid of any info that's dependent on free variables,
+    -- but keep other info (like the arity).
+    new_id = zapFragileIdInfo id2
 
 	-- Extend the substitution if the unique has changed,
 	-- or there's some useful occurrence information