X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FdeSugar%2FDesugar.lhs;h=b2131ca4f2a2cf6d2cbf6dfd6f59aa5e7458e974;hp=10858f83cb4cc5f94f64ca64e671086c77bac03a;hb=b2524b3960999fffdb3767900f58825903f6560f;hpb=549b6694dc6748e544eca9b8467aae75b737c9e7

diff --git a/compiler/deSugar/Desugar.lhs b/compiler/deSugar/Desugar.lhs
index 10858f8..b2131ca 100644
--- a/compiler/deSugar/Desugar.lhs
+++ b/compiler/deSugar/Desugar.lhs
@@ -43,6 +43,10 @@ import Data.List
 import Data.IORef
 import PrelNames
 import UniqSupply
+import UniqFM
+import CoreFVs
+import Type
+import Coercion
 \end{code}
 
 %************************************************************************
@@ -52,6 +56,7 @@ import UniqSupply
 %************************************************************************
 
 \begin{code}
+
 -- | Main entry point to the desugarer.
 deSugar :: HscEnv -> ModLocation -> TcGblEnv -> IO (Messages, Maybe ModGuts)
 -- Can modify PCS by faulting in more declarations
@@ -229,7 +234,7 @@ deSugar hsc_env
               final_prs = addExportFlagsAndRules target
 	      		      export_set keep_alive rules_for_locals (fromOL all_prs)
 
-              final_pgm = combineEvBinds ds_ev_binds final_prs
+              final_pgm = simplifyBinds $ combineEvBinds ds_ev_binds final_prs
 	-- Notice that we put the whole lot in a big Rec, even the foreign binds
 	-- When compiling PrelFloat, which defines data Float = F# Float#
 	-- we want F# to be in scope in the foreign marshalling code!
@@ -241,20 +246,24 @@ deSugar hsc_env
                (vcat [ pprCoreBindings final_pgm
                      , pprRules rules_for_imps ])
 
-	; (ds_binds, ds_rules_for_imps) <- simpleOptPgm dflags final_pgm rules_for_imps
-	      		 -- The simpleOptPgm gets rid of type 
-			 -- bindings plus any stupid dead code
+	; (final_pgm', rules_for_imps') <- if dopt Opt_F_simpleopt_before_flatten dflags
+                                            then simpleOptPgm dflags final_pgm rules_for_imps
+                                            else return (final_pgm, rules_for_imps)
 
-        ; ds_binds' <- if dopt Opt_F_coqpass dflags
+        ; ds_binds <- if dopt Opt_F_coqpass dflags
                        then do { us <- mkSplitUniqSupply '~'
+                               ; let do_flatten   = dopt Opt_F_flatten dflags
+                               ; let do_skolemize = dopt Opt_F_skolemize dflags
                                ; return (coqPassCoreToCore
+                                             do_flatten
+                                             do_skolemize
                                              hetmet_brak
                                              hetmet_esc
                                              hetmet_flatten
                                              hetmet_unflatten
                                              hetmet_flattened_id
                                              us
-                                             ds_binds
+                                             final_pgm'
                                              hetmet_PGArrow
                                              hetmet_PGArrow_unit
                                              hetmet_PGArrow_tensor
@@ -277,11 +286,17 @@ deSugar hsc_env
                                              hetmet_pga_curryl
                                              hetmet_pga_curryr)
                                }
-                       else return ds_binds
+                       else return final_pgm
 
-        ; dumpIfSet_dyn dflags Opt_D_coqpass "Coq Pass Output" $ text $ coqPassCoreToString ds_binds'
+	; (ds_binds', ds_rules_for_imps) <- if dopt Opt_F_simpleopt_before_flatten dflags
+                                            then return (ds_binds, rules_for_imps')
+                                            else simpleOptPgm dflags ds_binds rules_for_imps'
+	      		 -- The simpleOptPgm gets rid of type 
+			 -- bindings plus any stupid dead code
+
+        ; dumpIfSet_dyn dflags Opt_D_dump_proofs "Coq Pass Output" $ text $ coqPassCoreToString ds_binds'
 
-        ; dumpIfSet_dyn dflags Opt_D_dump_coqpass "After Coq Pass" (text $ showSDoc $ pprCoreBindings ds_binds')
+        ; dumpIfSet_dyn dflags Opt_D_coqpass "After Coq Pass" (text $ showSDoc $ pprCoreBindings ds_binds')
 
 	; endPass dflags CoreDesugar ds_binds' ds_rules_for_imps
 
@@ -520,6 +535,8 @@ switching off EnableRewriteRules.  See DsExpr.dsExplicitList.
 
 That keeps the desugaring of list comprehensions simple too.
 
+
+
 Nor do we want to warn of conversion identities on the LHS;
 the rule is precisly to optimise them:
   {-# RULES "fromRational/id" fromRational = id :: Rational -> Rational #-}
@@ -546,3 +563,35 @@ dsVect (L loc (HsVect v rhs))
 --        ; return $ Vect v (Just rhs')
 --       }
 \end{code}
+
+
+
+\begin{code}
+--
+-- Simplification routines run before the flattener.  We can't use
+-- simpleOptPgm -- it doesn't preserve the order of subexpressions or
+-- let-binding groups.
+--
+simplify :: Expr CoreBndr -> Expr CoreBndr
+simplify (Var v)                 = Var v
+simplify (App e1 e2)             = App (simplify e1) (simplify e2)
+simplify (Lit lit)               = Lit lit
+simplify (Note note e)           = Note note (simplify e)
+simplify (Cast e co)             = if tcEqType (fst $ coercionKind co) (snd $ coercionKind co)
+                                       then simplify e
+                                       else Cast (simplify e) co
+simplify (Lam v e)               = Lam v (simplify e)
+simplify (Type t)                = Type t
+simplify (Case e b ty as)        = Case (simplify e) b ty (map (\(a,b,e) -> (a,b,simplify e)) as)
+simplify (Let bind body)         = foldr Let (simplify body) (simplifyBind bind)
+
+simplifyBind :: Bind CoreBndr -> [Bind CoreBndr]
+simplifyBind (NonRec b e)             = [NonRec b (simplify e)]
+simplifyBind (Rec [])                 = []
+simplifyBind (Rec (rbs@((b,e):rbs'))) =
+    if or $ map (\x -> elemUFM x (exprFreeIds e)) (map fst rbs)
+    then [Rec (map (\(v,e) -> (v,simplify e)) rbs)]
+    else (NonRec b (simplify e)):(simplifyBind $ Rec rbs')
+
+simplifyBinds = concatMap simplifyBind
+\end{code}