Command-line options for selecting DPH backend

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

diff --git a/compiler/simplCore/SimplCore.lhs b/compiler/simplCore/SimplCore.lhs
index 95bd40b..86d3ec0 100644 (file)
--- a/compiler/simplCore/SimplCore.lhs
+++ b/compiler/simplCore/SimplCore.lhs
@@ -155,13 +155,13 @@ doCorePass CoreCSE                       = {-# SCC "CommonSubExpr" #-} trBinds  cseProgram
 doCorePass CoreLiberateCase           = {-# SCC "LiberateCase" #-}  liberateCase
 doCorePass CoreDoFloatInwards          = {-# SCC "FloatInwards" #-}  trBinds  floatInwards
 doCorePass (CoreDoFloatOutwards f)     = {-# SCC "FloatOutwards" #-} trBindsU (floatOutwards f)
-doCorePass CoreDoStaticArgs           = {-# SCC "StaticArgs" #-}    trBinds  doStaticArgs
+doCorePass CoreDoStaticArgs           = {-# SCC "StaticArgs" #-}    trBindsU  doStaticArgs
 doCorePass CoreDoStrictness           = {-# SCC "Stranal" #-}       trBinds  dmdAnalPgm
 doCorePass CoreDoWorkerWrapper         = {-# SCC "WorkWrap" #-}      trBindsU wwTopBinds
 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 ())
@@ -339,12 +339,19 @@ updateBinders local_rules binds
                                -- arising from specialisation pragmas
 \end{code}
 
-
-We must do some gentle simplification on the template (but not the RHS)
-of each rule.  The case that forced me to add this was the fold/build rule,
+Note [Simplifying the left-hand side of a RULE]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+We must do some gentle simplification on the lhs (template) of each
+rule.  The case that forced me to add this was the fold/build rule,
 which without simplification looked like:
        fold k z (build (/\a. g a))  ==>  ...
 This doesn't match unless you do eta reduction on the build argument.
+Similarly for a LHS like
+       augment g (build h) 
+we do not want to get
+       augment (\a. g a) (build h)
+otherwise we don't match when given an argument like
+       augment (\a. h a a) (build h)
 
 \begin{code}
 simplRule env rule@(BuiltinRule {})
@@ -375,11 +382,17 @@ simplExprGently :: SimplEnv -> CoreExpr -> SimplM CoreExpr
 --     alone leaves tons of crud.
 -- Used (a) for user expressions typed in at the interactive prompt
 --     (b) the LHS and RHS of a RULE
+--     (c) Template Haskell splices
 --
 -- The name 'Gently' suggests that the SimplifierMode is SimplGently,
 -- and in fact that is so.... but the 'Gently' in simplExprGently doesn't
 -- enforce that; it just simplifies the expression twice
 
+-- It's important that simplExprGently does eta reduction; see
+-- Note [Simplifying the left-hand side of a RULE] above.  The
+-- simplifier does indeed do eta reduction (it's in Simplify.completeLam)
+-- but only if -O is on.
+
 simplExprGently env expr = do
     expr1 <- simplExpr env (occurAnalyseExpr expr)
     simplExpr env (occurAnalyseExpr expr1)
@@ -480,15 +493,13 @@ simplifyPgm mode switches hsc_env us imp_rule_base guts
        -- iteration_no is the number of the iteration we are
        -- about to begin, with '1' for the first
       | iteration_no > max_iterations  -- Stop if we've run out of iterations
-      = do {
-           when (debugIsOn && (max_iterations > 2)) $
-                   hPutStr stderr ("NOTE: Simplifier still going after " ++ 
-                               show max_iterations ++ 
-                               " iterations; bailing out.  Size = " ++ show (coreBindsSize binds) ++ "\n" )
+      =  WARN(debugIsOn && (max_iterations > 2),
+                text ("Simplifier still going after " ++
+                               show max_iterations ++
+                               " iterations; bailing out.  Size = " ++ show (coreBindsSize binds) ++ "\n" ))
                -- Subtract 1 from iteration_no to get the
                -- number of iterations we actually completed
-           ; return ("Simplifier bailed out", iteration_no - 1, counts, binds)
-       }
+           return ("Simplifier bailed out", iteration_no - 1, counts, binds)
 
       -- Try and force thunks off the binds; significantly reduces
       -- space usage, especially with -O.  JRS, 000620.