X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FsimplCore%2FSimplify.lhs;h=f718bcb7849675976655b4ab21590cdfcc99a233;hb=90b9566607ef837329434657c8fabc4bdffdf1af;hp=80fced5bd91c236f8f9df8b04fa31d455e6844c9;hpb=53f99d8465ec50f7c37c65658fa346094bd37ded;p=ghc-hetmet.git

diff --git a/compiler/simplCore/Simplify.lhs b/compiler/simplCore/Simplify.lhs
index 80fced5..f718bcb 100644
--- a/compiler/simplCore/Simplify.lhs
+++ b/compiler/simplCore/Simplify.lhs
@@ -521,7 +521,7 @@ makeTrivial env expr
   | exprIsTrivial expr
   = return (env, expr)
   | otherwise           -- See Note [Take care] below
-  = do  { var <- newId FSLIT("a") (exprType expr)
+  = do  { var <- newId (fsLit "a") (exprType expr)
         ; env' <- completeNonRecX env False var var expr
         ; return (env', substExpr env' (Var var)) }
 \end{code}
@@ -1265,15 +1265,18 @@ inlined.
 
 Note [no-case-of-case]
 ~~~~~~~~~~~~~~~~~~~~~~
-There is a time we *don't* want to do that, namely when
--fno-case-of-case is on.  This happens in the first simplifier pass,
-and enhances full laziness.  Here's the bad case:
-        f = \ y -> ...(case x of I# v -> ...(case x of ...) ... )
-If we eliminate the inner case, we trap it inside the I# v -> arm,
-which might prevent some full laziness happening.  I've seen this
-in action in spectral/cichelli/Prog.hs:
-         [(m,n) | m <- [1..max], n <- [1..max]]
-Hence the check for NoCaseOfCase.
+We *used* to suppress the binder-swap in case expressoins when 
+-fno-case-of-case is on.  Old remarks:
+    "This happens in the first simplifier pass,
+    and enhances full laziness.  Here's the bad case:
+            f = \ y -> ...(case x of I# v -> ...(case x of ...) ... )
+    If we eliminate the inner case, we trap it inside the I# v -> arm,
+    which might prevent some full laziness happening.  I've seen this
+    in action in spectral/cichelli/Prog.hs:
+             [(m,n) | m <- [1..max], n <- [1..max]]
+    Hence the check for NoCaseOfCase."
+However, now the full-laziness pass itself reverses the binder-swap, so this
+check is no longer necessary.
 
 Note [Suppressing the case binder-swap]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1485,7 +1488,7 @@ simplCaseBinder env0 scrut0 case_bndr0 alts
 
     improve_seq fam_envs env scrut case_bndr case_bndr1 [(DEFAULT,_,_)]
         | Just (co, ty2) <- topNormaliseType fam_envs (idType case_bndr1)
-        =  do { case_bndr2 <- newId FSLIT("nt") ty2
+        =  do { case_bndr2 <- newId (fsLit "nt") ty2
               ; let rhs  = DoneEx (Var case_bndr2 `Cast` mkSymCoercion co)
                     env2 = extendIdSubst env case_bndr rhs
               ; return (env2, scrut `Cast` co, case_bndr2) }
@@ -1495,9 +1498,9 @@ simplCaseBinder env0 scrut0 case_bndr0 alts
 
 
     improve_case_bndr env scrut case_bndr
-        | switchIsOn (getSwitchChecker env) NoCaseOfCase
-                -- See Note [no-case-of-case]
-        = (env, case_bndr)
+        -- See Note [no-case-of-case]
+	--  | switchIsOn (getSwitchChecker env) NoCaseOfCase
+	--  = (env, case_bndr)
 
         | otherwise     -- Failed try; see Note [Suppressing the case binder-swap]
                         --     not (isEvaldUnfolding (idUnfolding v))
@@ -1876,10 +1879,10 @@ mkDupableAlt env case_bndr' (con, bndrs', rhs')
         ; (final_bndrs', final_args)    -- Note [Join point abstraction]
                 <- if (any isId used_bndrs')
                    then return (used_bndrs', varsToCoreExprs used_bndrs')
-                    else do { rw_id <- newId FSLIT("w") realWorldStatePrimTy
+                    else do { rw_id <- newId (fsLit "w") realWorldStatePrimTy
                             ; return ([rw_id], [Var realWorldPrimId]) }
 
-        ; join_bndr <- newId FSLIT("$j") (mkPiTypes final_bndrs' rhs_ty')
+        ; join_bndr <- newId (fsLit "$j") (mkPiTypes final_bndrs' rhs_ty')
                 -- Note [Funky mkPiTypes]
 
         ; let   -- We make the lambdas into one-shot-lambdas.  The