[project @ 2003-06-30 14:27:51 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 7412f0d..46f2ba2 100644 (file)
--- a/ghc/compiler/coreSyn/CoreUnfold.lhs
+++ b/ghc/compiler/coreSyn/CoreUnfold.lhs
@@ -56,9 +56,10 @@ import PrelNames     ( hasKey, buildIdKey, augmentIdKey )
 import Bag
 import FastTypes
 import Outputable
+import Util
 
 #if __GLASGOW_HASKELL__ >= 404
-import GlaExts         ( fromInt, Int# )
+import GLAEXTS         ( Int# )
 #endif
 \end{code}
 
@@ -297,7 +298,7 @@ sizeExpr bOMB_OUT_SIZE top_args expr
       | fun `hasKey` augmentIdKey = augmentSize
       | otherwise 
       = case globalIdDetails fun of
-         DataConId dc -> conSizeN dc (valArgCount args)
+         DataConWorkId dc -> conSizeN dc (valArgCount args)
 
          FCallId fc   -> sizeN opt_UF_DearOp
          PrimOpId op  -> primOpSize op (valArgCount args)
@@ -353,6 +354,11 @@ data ExprSize = TooBig
                       FastInt          -- Size to subtract if result is scrutinised 
                                        -- by a case expression
 
+-- subtract the discount before deciding whether to bale out. eg. we
+-- want to inline a large constructor application into a selector:
+--     tup = (a_1, ..., a_99)
+--     x = case tup of ...
+--
 mkSizeIs max n xs d | (n -# d) ># max = TooBig
                    | otherwise       = SizeIs n xs d
  
@@ -453,16 +459,12 @@ couldBeSmallEnoughToInline threshold rhs = case calcUnfoldingGuidance threshold
                                                UnfoldNever -> False
                                                other       -> True
 
-certainlyWillInline :: Id -> Bool
-       -- Sees if the Id is pretty certain to inline   
-certainlyWillInline v
-  = case idUnfolding v of
-
-       CoreUnfolding _ _ _ is_cheap g@(UnfoldIfGoodArgs n_vals _ size _)
-          ->    is_cheap
-             && size - (n_vals +1) <= opt_UF_UseThreshold
-
-       other -> False
+certainlyWillInline :: Unfolding -> Bool
+  -- Sees if the unfolding is pretty certain to inline 
+certainlyWillInline (CoreUnfolding _ _ _ is_cheap (UnfoldIfGoodArgs n_vals _ size _))
+  = is_cheap && size - (n_vals +1) <= opt_UF_UseThreshold
+certainlyWillInline other
+  = False
 \end{code}
 
 @okToUnfoldInHifile@ is used when emitting unfolding info into an interface
@@ -577,6 +579,11 @@ callSiteInline dflags active_inline inline_call occ id arg_infos interesting_con
                -- then if the context is totally uninteresting (not applied, not scrutinised)
                -- there is no point in substituting because it might just increase allocation,
                -- by allocating the function itself many times
+               -- Note [Jan 2002]: this comment looks out of date.  The actual code
+               -- doesn't inline *ever* in an uninteresting context.  Why not?  I
+               -- think it's just because we don't want to inline top-level constants
+               -- into uninteresting contexts, lest we (for example) re-nest top-level
+               -- literal lists.
                --
                -- Note: there used to be a '&& not top_level' in the guard above,
                --       but that stopped us inlining top-level functions used only once,
@@ -585,7 +592,7 @@ callSiteInline dflags active_inline inline_call occ id arg_infos interesting_con
                        -- If (not in_lam) && one_br then PreInlineUnconditionally
                        -- should have caught it, shouldn't it?  Unless it's a top
                        -- level thing.
-           not (null arg_infos) || interesting_cont
+           notNull arg_infos || interesting_cont
 
          | otherwise
          = case guidance of
@@ -663,7 +670,7 @@ computeDiscount n_vals_wanted arg_discounts res_discount arg_infos result_used
                        -- Discount of 1 for each arg supplied, because the 
                        -- result replaces the call
     round (opt_UF_KeenessFactor * 
-          fromInt (arg_discount + result_discount))
+          fromIntegral (arg_discount + result_discount))
   where
     arg_discount = sum (zipWith mk_arg_discount arg_discounts arg_infos)