Remove unused OccInfo (simplification)

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

diff --git a/compiler/simplCore/SimplEnv.lhs b/compiler/simplCore/SimplEnv.lhs
index 9bce1e0..fca0d61 100644 (file)
--- a/compiler/simplCore/SimplEnv.lhs
+++ b/compiler/simplCore/SimplEnv.lhs
@@ -124,7 +124,7 @@ type SimplIdSubst = IdEnv SimplSR   -- IdId |--> OutExpr
 
 data SimplSR
   = DoneEx OutExpr             -- Completed term
-  | DoneId OutId OccInfo       -- Completed term variable, with occurrence info
+  | DoneId OutId               -- Completed term variable
   | ContEx TvSubstEnv          -- A suspended substitution
           SimplIdSubst
           InExpr        
@@ -151,11 +151,6 @@ seIdSubst:
                a77 -> a77
        from the substitution, when we decide not to clone a77, but it's quite 
        legitimate to put the mapping in the substitution anyway.
-       
-       Indeed, we do so when we want to pass fragile OccInfo to the
-       occurrences of the variable; we add a substitution
-               x77 -> DoneId x77 occ
-       to record x's occurrence information.]
 
        Furthermore, consider 
                let x = case k of I# x77 -> ... in
@@ -168,12 +163,9 @@ seIdSubst:
        Of course, the substitution *must* applied! Things in its domain 
        simply aren't necessarily bound in the result.
 
-* substId adds a binding (DoneId new_id occ) to the substitution if 
-       EITHER the Id's unique has changed
-       OR     the Id has interesting occurrence information
-  So in effect you can only get to interesting occurrence information
-  by looking up the *old* Id; it's not really attached to the new id
-  at all.
+* substId adds a binding (DoneId new_id) to the substitution if 
+       the Id's unique has changed
+
 
   Note, though that the substitution isn't necessarily extended
   if the type changes.  Why not?  Because of the next point:
@@ -292,19 +284,12 @@ getRules = seExtRules
 substId :: SimplEnv -> Id -> SimplSR
 substId (SimplEnv { seInScope = in_scope, seIdSubst = ids }) v 
   | not (isLocalId v) 
-  = DoneId v NoOccInfo
+  = DoneId v
   | otherwise  -- A local Id
   = case lookupVarEnv ids v of
-       Just (DoneId v occ) -> DoneId (refine v) occ
-       Just res            -> res
-       Nothing             -> let v' = refine v
-                              in DoneId v' (idOccInfo v')
-               -- We don't put LoopBreakers in the substitution (unless then need
-               -- to be cloned for name-clash rasons), so the idOccInfo is
-               -- very important!  If isFragileOcc returned True for
-               -- loop breakers we could avoid this call, but at the expense
-               -- of adding more to the substitution, and building new Ids
-               -- a bit more often than really necessary
+       Just (DoneId v) -> DoneId (refine v)
+       Just res        -> res
+       Nothing         -> DoneId (refine v)
   where
        -- Get the most up-to-date thing from the in-scope set
        -- Even though it isn't in the substitution, it may be in
@@ -392,7 +377,7 @@ substIdBndr env@(SimplEnv { seInScope = in_scope, seIdSubst = id_subst})
        -- Extend the substitution if the unique has changed
        -- See the notes with substTyVarBndr for the delSubstEnv
     new_subst | new_id /= old_id
-             = extendVarEnv id_subst old_id (DoneId new_id (idOccInfo old_id))
+             = extendVarEnv id_subst old_id (DoneId new_id)
              | otherwise 
              = delVarEnv id_subst old_id
 \end{code}
@@ -458,8 +443,8 @@ substLetIdBndr env@(SimplEnv { seInScope = in_scope, seIdSubst = id_subst }) old
        -- or there's some useful occurrence information
        -- See the notes with substTyVarBndr for the delSubstEnv
     occ_info = occInfo (idInfo old_id)
-    new_subst | new_id /= old_id || isFragileOcc occ_info
-             = extendVarEnv id_subst old_id (DoneId new_id occ_info)
+    new_subst | new_id /= old_id
+             = extendVarEnv id_subst old_id (DoneId new_id)
              | otherwise 
              = delVarEnv id_subst old_id
 \end{code}
@@ -609,7 +594,7 @@ mkCoreSubst (SimplEnv { seInScope = in_scope, seTvSubst = tv_env, seIdSubst = id
     mk_subst tv_env id_env = CoreSubst.mkSubst in_scope tv_env (mapVarEnv fiddle id_env)
 
     fiddle (DoneEx e)       = e
-    fiddle (DoneId v occ)   = Var v
+    fiddle (DoneId v)       = Var v
     fiddle (ContEx tv id e) = CoreSubst.substExpr (mk_subst tv id) e
 
 substExpr :: SimplEnv -> CoreExpr -> CoreExpr