[project @ 2001-03-23 10:46:27 by simonpj]

[ghc-hetmet.git] / ghc / compiler / coreSyn / CoreUnfold.lhs

diff --git a/ghc/compiler/coreSyn/CoreUnfold.lhs b/ghc/compiler/coreSyn/CoreUnfold.lhs
index 4ed1cb4..7db6f2d 100644 (file)
--- a/ghc/compiler/coreSyn/CoreUnfold.lhs
+++ b/ghc/compiler/coreSyn/CoreUnfold.lhs
@@ -20,7 +20,7 @@ module CoreUnfold (
        mkOtherCon, otherCons,
        unfoldingTemplate, maybeUnfoldingTemplate,
        isEvaldUnfolding, isValueUnfolding, isCheapUnfolding, isCompulsoryUnfolding,
-       hasUnfolding, hasSomeUnfolding,
+       hasUnfolding, hasSomeUnfolding, neverUnfold,
 
        couldBeSmallEnoughToInline, 
        certainlyWillInline, 
@@ -42,14 +42,14 @@ import CoreSyn
 import PprCore         ( pprCoreExpr )
 import OccurAnal       ( occurAnalyseGlobalExpr )
 import CoreUtils       ( exprIsValue, exprIsCheap, exprIsTrivial )
-import Id              ( Id, idType, idFlavour, isId,
+import Id              ( Id, idType, isId,
                          idSpecialisation, idInlinePragma, idUnfolding,
-                         isPrimOpId_maybe
+                         isPrimOpId_maybe, globalIdDetails
                        )
 import VarSet
-import Literal         ( isLitLitLit, litIsDupable )
+import Literal         ( isLitLitLit, litSize )
 import PrimOp          ( PrimOp(..), primOpIsDupable, primOpOutOfLine, ccallIsCasm )
-import IdInfo          ( InlinePragInfo(..), OccInfo(..), IdFlavour(..),
+import IdInfo          ( InlinePragInfo(..), OccInfo(..), GlobalIdDetails(..),
                          isNeverInlinePrag
                        )
 import Type            ( isUnLiftedType )
@@ -188,13 +188,20 @@ sizeExpr bOMB_OUT_SIZE top_args expr
     size_up (Type t)         = sizeZero        -- Types cost nothing
     size_up (Var v)           = sizeOne
 
-    size_up (Note _ body)     = size_up body   -- Notes cost nothing
+    size_up (Note InlineMe body) = sizeOne     -- Inline notes make it look very small
+       -- This can be important.  If you have an instance decl like this:
+       --      instance Foo a => Foo [a] where
+       --         {-# INLINE op1, op2 #-}
+       --         op1 = ...
+       --         op2 = ...
+       -- then we'll get a dfun which is a pair of two INLINE lambdas
 
-    size_up (App fun (Type t))  = size_up fun
-    size_up (App fun arg)     = size_up_app fun [arg]
+    size_up (Note _        body) = size_up body        -- Other notes cost nothing
 
-    size_up (Lit lit) | litIsDupable lit = sizeOne
-                     | otherwise        = sizeN opt_UF_DearOp  -- For lack of anything better
+    size_up (App fun (Type t)) = size_up fun
+    size_up (App fun arg)      = size_up_app fun [arg]
+
+    size_up (Lit lit)         = sizeN (litSize lit)
 
     size_up (Lam b e) | isId b    = lamScrutDiscount (size_up e `addSizeN` 1)
                      | otherwise = size_up e
@@ -220,7 +227,7 @@ sizeExpr bOMB_OUT_SIZE top_args expr
 
        (a) It's too eager.  We don't want to inline a wrapper into a
            context with no benefit.  
-           E.g.  \ x. f (x+x)          o point in inlining (+) here!
+           E.g.  \ x. f (x+x)          no point in inlining (+) here!
 
        (b) It's ineffective. Once g's wrapper is inlined, its case-expressions 
            aren't scrutinising arguments any more
@@ -289,7 +296,7 @@ sizeExpr bOMB_OUT_SIZE top_args expr
       | fun `hasKey` buildIdKey   = buildSize
       | fun `hasKey` augmentIdKey = augmentSize
       | otherwise 
-      = case idFlavour fun of
+      = case globalIdDetails fun of
          DataConId dc -> conSizeN (valArgCount args)
 
          PrimOpId op  -> primOpSize op (valArgCount args)
@@ -355,8 +362,6 @@ data ExprSize = TooBig
                       FastInt          -- Size to subtract if result is scrutinised 
                                        -- by a case expression
 
-isTooBig TooBig = True
-isTooBig _      = False
 
 maxSize TooBig         _                                 = TooBig
 maxSize _              TooBig                            = TooBig
@@ -376,7 +381,12 @@ conSizeN n      = SizeIs (_ILIT 1) emptyBag (iUnbox n +# _ILIT 1)
 
 primOpSize op n_args
  | not (primOpIsDupable op) = sizeN opt_UF_DearOp
- | not (primOpOutOfLine op) = sizeZero                 -- These are good to inline
+ | not (primOpOutOfLine op) = sizeN (1 - n_args)
+       -- Be very keen to inline simple primops.
+       -- We give a discount of 1 for each arg so that (op# x y z) costs 1.
+       -- I found occasions where we had 
+       --      f x y z = case op# x y z of { s -> (# s, () #) }
+       -- and f wasn't getting inlined
  | otherwise               = sizeOne
 
 buildSize = SizeIs (-2#) emptyBag 4#
@@ -569,7 +579,9 @@ callSiteInline dflags black_listed inline_call occ id arg_infos interesting_cont
                -- Note: there used to be a '&& not top_level' in the guard above,
                --       but that stopped us inlining top-level functions used only once,
                --       which is stupid
-         = not in_lam || not (null arg_infos) || interesting_cont
+         = WARN( not in_lam, ppr id )  -- If (not in_lam) && one_br then PreInlineUnconditionally
+                                       -- should have caught it, shouldn't it?
+           not (null arg_infos) || interesting_cont
 
          | otherwise
          = case guidance of
@@ -612,7 +624,6 @@ callSiteInline dflags black_listed inline_call occ id arg_infos interesting_cont
                                                 arg_infos really_interesting_cont
                
     in    
-#ifdef DEBUG
     if dopt Opt_D_dump_inlinings dflags then
        pprTrace "Considering inlining"
                 (ppr id <+> vcat [text "black listed:" <+> ppr black_listed,
@@ -628,7 +639,6 @@ callSiteInline dflags black_listed inline_call occ id arg_infos interesting_cont
                                   else empty])
                  result
     else
-#endif
     result
     }