Command-line options for selecting DPH backend

It's -fdph-seq and -fdph-par at the moment, I'll think of a nicer setup later.

compiler/main/DynFlags.hs

@@ -23,6 +23,7 @@ module DynFlags (
         Option(..),
         DynLibLoader(..),
         fFlags, xFlags,
+        DPHBackend(..),
 
         -- Configuration of the core-to-core and stg-to-stg phases
         CoreToDo(..),
@@ -310,6 +311,8 @@ data DynFlags = DynFlags {
   mainFunIs             :: Maybe String,
   ctxtStkDepth          :: Int,         -- Typechecker context stack depth
 
+  dphBackend            :: DPHBackend,
+
   thisPackage           :: PackageId,
 
   -- ways
@@ -501,6 +504,8 @@ defaultDynFlags =
         mainFunIs               = Nothing,
         ctxtStkDepth            = mAX_CONTEXT_REDUCTION_DEPTH,
 
+        dphBackend              = DPHPar,
+
         thisPackage             = mainPackageId,
 
         objectDir               = Nothing,
@@ -807,7 +812,7 @@ data CoreToDo           -- These are diff core-to-core passes,
   | CoreCSE
   | CoreDoRuleCheck Int{-CompilerPhase-} String -- Check for non-application of rules
                                                 -- matching this string
-  | CoreDoVectorisation
+  | CoreDoVectorisation DPHBackend
   | CoreDoNothing                -- Useful when building up
   | CoreDoPasses [CoreToDo]      -- lists of these things
 
@@ -848,7 +853,6 @@ getCoreToDo dflags
     spec_constr   = dopt Opt_SpecConstr dflags
     liberate_case = dopt Opt_LiberateCase dflags
     rule_check    = ruleCheck dflags
-    vectorisation = dopt Opt_Vectorise dflags
     static_args   = dopt Opt_StaticArgumentTransformation dflags
 
     maybe_rule_check phase = runMaybe rule_check (CoreDoRuleCheck phase)
@@ -861,6 +865,11 @@ getCoreToDo dflags
             maybe_rule_check phase
           ]
 
+    vectorisation
+      = runWhen (dopt Opt_Vectorise dflags)
+        $ CoreDoPasses [ simpl_gently, CoreDoVectorisation (dphBackend dflags) ]
+
+
                 -- By default, we have 2 phases before phase 0.
 
                 -- Want to run with inline phase 2 after the specialiser to give
@@ -895,7 +904,7 @@ getCoreToDo dflags
 
     core_todo =
      if opt_level == 0 then
-       [runWhen vectorisation (CoreDoPasses [ simpl_gently, CoreDoVectorisation ]),
+       [vectorisation,
         simpl_phase 0 ["final"] max_iter]
      else {- opt_level >= 1 -} [
 
@@ -905,12 +914,12 @@ getCoreToDo dflags
     -- after this before anything else
         runWhen static_args (CoreDoPasses [ simpl_gently, CoreDoStaticArgs ]),
 
-        -- initial simplify: mk specialiser happy: minimum effort please
-        simpl_gently,
-
         -- We run vectorisation here for now, but we might also try to run
         -- it later
-        runWhen vectorisation (CoreDoPasses [ CoreDoVectorisation, simpl_gently ]),
+        vectorisation,
+
+        -- initial simplify: mk specialiser happy: minimum effort please
+        simpl_gently,
 
         -- Specialisation is best done before full laziness
         -- so that overloaded functions have all their dictionary lambdas manifest
@@ -1323,6 +1332,15 @@ dynamic_flags = [
          (IntSuffix $ \n -> upd $ \dfs -> dfs{ ctxtStkDepth = n })
          Supported
 
+        ------ DPH flags ----------------------------------------------------
+
+  , Flag "fdph-seq"
+         (NoArg (upd (setDPHBackend DPHSeq)))
+         Supported
+  , Flag "fdph-par"
+         (NoArg (upd (setDPHBackend DPHPar)))
+         Supported
+
         ------ Compiler flags -----------------------------------------------
 
   , Flag "fasm"             (NoArg (setObjTarget HscAsm)) Supported
@@ -1711,6 +1729,11 @@ setDPHOpt dflags = setOptLevel 2 (dflags { maxSimplIterations  = 20
                    `dopt_set`   Opt_DictsCheap
                    `dopt_unset` Opt_MethodSharing
 
+data DPHBackend = DPHPar
+                | DPHSeq
+
+setDPHBackend :: DPHBackend -> DynFlags -> DynFlags
+setDPHBackend backend dflags = dflags { dphBackend = backend }
 
 
 setMainIs :: String -> DynP ()

compiler/simplCore/SimplCore.lhs

@@ -161,7 +161,7 @@ doCorePass CoreDoWorkerWrapper         = {-# SCC "WorkWrap" #-}      trBindsU ww
 doCorePass CoreDoSpecialising          = {-# SCC "Specialise" #-}    trBindsU specProgram
 doCorePass CoreDoSpecConstr	       = {-# SCC "SpecConstr" #-}    trBindsU specConstrProgram
 doCorePass CoreDoGlomBinds	       = trBinds glomBinds
-doCorePass CoreDoVectorisation         = {-# SCC "Vectorise" #-}     vectorise
+doCorePass (CoreDoVectorisation be)    = {-# SCC "Vectorise" #-}     vectorise be
 doCorePass CoreDoPrintCore	       = observe printCore
 doCorePass (CoreDoRuleCheck phase pat) = ruleCheck phase pat
 doCorePass CoreDoNothing	       = observe (\ _ _ -> return ())

compiler/vectorise/VectMonad.hs

@@ -37,7 +37,7 @@ module VectMonad (
 import VectBuiltIn
 
 import HscTypes
-import Module        ( dphSeqPackageId )
+import Module           ( PackageId )
 import CoreSyn
 import TyCon
 import DataCon
@@ -479,8 +479,8 @@ lookupFamInst tycon tys
                       (ppr $ mkTyConApp tycon tys)
        }
 
-initV :: HscEnv -> ModGuts -> VectInfo -> VM a -> IO (Maybe (VectInfo, a))
-initV hsc_env guts info p
+initV :: PackageId -> HscEnv -> ModGuts -> VectInfo -> VM a -> IO (Maybe (VectInfo, a))
+initV pkg hsc_env guts info p
   = do
       Just r <- initDs hsc_env (mg_module guts)
                                (mg_rdr_env guts)
@@ -491,7 +491,7 @@ initV hsc_env guts info p
 
     go =
       do
-        builtins       <- initBuiltins dphSeqPackageId
+        builtins       <- initBuiltins pkg
         builtin_vars   <- initBuiltinVars builtins
         builtin_tycons <- initBuiltinTyCons builtins
         let builtin_datacons = initBuiltinDataCons builtins

compiler/vectorise/Vectorise.hs

@@ -10,6 +10,7 @@ import VectCore
 import DynFlags
 import HscTypes
 
+import Module               ( dphSeqPackageId, dphParPackageId )
 import CoreLint             ( showPass, endPass )
 import CoreSyn
 import CoreUtils
@@ -36,19 +37,23 @@ import FastString
 import Control.Monad        ( liftM, liftM2, zipWithM )
 import Data.List            ( sortBy, unzip4 )
 
-vectorise :: HscEnv -> UniqSupply -> RuleBase -> ModGuts
+vectorise :: DPHBackend -> HscEnv -> UniqSupply -> RuleBase -> ModGuts
           -> IO (SimplCount, ModGuts)
-vectorise hsc_env _ _ guts
+vectorise backend hsc_env _ _ guts
   = do
       showPass dflags "Vectorisation"
       eps <- hscEPS hsc_env
       let info = hptVectInfo hsc_env `plusVectInfo` eps_vect_info eps
-      Just (info', guts') <- initV hsc_env guts info (vectModule guts)
+      Just (info', guts') <- initV (backendPackage backend) hsc_env guts info
+                                   (vectModule guts)
       endPass dflags "Vectorisation" Opt_D_dump_vect (mg_binds guts')
       return (zeroSimplCount dflags, guts' { mg_vect_info = info' })
   where
     dflags = hsc_dflags hsc_env
 
+    backendPackage DPHSeq  = dphSeqPackageId
+    backendPackage DPHPar  = dphParPackageId
+
 vectModule :: ModGuts -> VM ModGuts
 vectModule guts
   = do