X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FsimplCore%2FSetLevels.lhs;h=0235981a804b6171c25b6bf3da1eb2f5f65ec1bf;hb=22b34988e2b156593d7cfc9b72d6cc0ab471a1d2;hp=4b4a3498aa83bbb20e5a4cdb41d5c38b38c0b89a;hpb=eced5e4068f4cb5da397ca1fd4eeea462f197503;p=ghc-hetmet.git

diff --git a/compiler/simplCore/SetLevels.lhs b/compiler/simplCore/SetLevels.lhs
index 4b4a349..0235981 100644
--- a/compiler/simplCore/SetLevels.lhs
+++ b/compiler/simplCore/SetLevels.lhs
@@ -358,7 +358,8 @@ lvlExpr ctxt_lvl env (_, AnnCase expr case_bndr ty alts) = do
 @lvlMFE@ is just like @lvlExpr@, except that it might let-bind
 the expression, so that it can itself be floated.
 
-[NOTE: unlifted MFEs]
+Note [Unlifted MFEs]
+~~~~~~~~~~~~~~~~~~~~~
 We don't float unlifted MFEs, which potentially loses big opportunites.
 For example:
 	\x -> f (h y)
@@ -375,9 +376,16 @@ lvlMFE ::  Bool			-- True <=> strict context [body of case or let]
 lvlMFE _ _ _ (_, AnnType ty)
   = return (Type ty)
 
+-- No point in floating out an expression wrapped in a coercion;
+-- If we do we'll transform  lvl = e |> co 
+--			 to  lvl' = e; lvl = lvl' |> co
+-- and then inline lvl.  Better just to float out the payload.
+lvlMFE strict_ctxt ctxt_lvl env (_, AnnCast e co)
+  = do	{ expr' <- lvlMFE strict_ctxt ctxt_lvl env e
+	; return (Cast expr' co) }
 
 lvlMFE strict_ctxt ctxt_lvl env ann_expr@(fvs, _)
-  |  isUnLiftedType ty			-- Can't let-bind it; see [NOTE: unlifted MFEs]
+  |  isUnLiftedType ty			-- Can't let-bind it; see Note [Unlifted MFEs]
   || isInlineCtxt ctxt_lvl		-- Don't float out of an __inline__ context
   || exprIsTrivial expr			-- Never float if it's trivial
   || not good_destination
@@ -481,7 +489,9 @@ lvlBind :: TopLevelFlag		-- Used solely to decide whether to clone
 	-> LvlM (LevelledBind, LevelEnv)
 
 lvlBind top_lvl ctxt_lvl env (AnnNonRec bndr rhs@(rhs_fvs,_))
-  | isInlineCtxt ctxt_lvl		-- Don't do anything inside InlineMe
+  |  isTyVar bndr 		-- Don't do anything for TyVar binders
+				--   (simplifier gets rid of them pronto)
+  || isInlineCtxt ctxt_lvl	-- Don't do anything inside InlineMe
   = do rhs' <- lvlExpr ctxt_lvl env rhs
        return (NonRec (TB bndr ctxt_lvl) rhs', env)
 
@@ -595,7 +605,7 @@ lvlLamBndrs lvl bndrs
 	[] bndrs
   where
     go old_lvl bumped_major rev_lvld_bndrs (bndr:bndrs)
-	| isId bndr && 			-- Go to the next major level if this is a value binder,
+	| isId bndr &&	    		-- Go to the next major level if this is a value binder,
 	  not bumped_major && 		-- and we havn't already gone to the next level (one jump per group)
 	  not (isOneShotLambda bndr)	-- and it isn't a one-shot lambda
 	= go new_lvl True (TB bndr new_lvl : rev_lvld_bndrs) bndrs
@@ -681,10 +691,10 @@ initialEnv :: FloatOutSwitches -> LevelEnv
 initialEnv float_lams = (float_lams, emptyVarEnv, emptySubst, emptyVarEnv)
 
 floatLams :: LevelEnv -> Bool
-floatLams (FloatOutSw float_lams _, _, _, _) = float_lams
+floatLams (fos, _, _, _) = floatOutLambdas fos
 
 floatConsts :: LevelEnv -> Bool
-floatConsts (FloatOutSw _ float_consts, _, _, _) = float_consts
+floatConsts (fos, _, _, _) = floatOutConstants fos
 
 extendLvlEnv :: LevelEnv -> [TaggedBndr Level] -> LevelEnv
 -- Used when *not* cloning
@@ -841,7 +851,7 @@ newPolyBndrs dest_lvl env abs_vars bndrs = do
     let new_bndrs = zipWith mk_poly_bndr bndrs uniqs
     return (extendPolyLvlEnv dest_lvl env abs_vars (bndrs `zip` new_bndrs), new_bndrs)
   where
-    mk_poly_bndr bndr uniq = transferPolyIdInfo bndr $ 	-- Note [transferPolyIdInfo] in Id.lhs
+    mk_poly_bndr bndr uniq = transferPolyIdInfo bndr abs_vars $ 	-- Note [transferPolyIdInfo] in Id.lhs
 			     mkSysLocal (mkFastString str) uniq poly_ty
 			   where
 			     str     = "poly_" ++ occNameString (getOccName bndr)