Make record selectors into ordinary functions

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

diff --git a/compiler/coreSyn/CoreUnfold.lhs b/compiler/coreSyn/CoreUnfold.lhs
index b6706c1..38513af 100644 (file)
--- a/compiler/coreSyn/CoreUnfold.lhs
+++ b/compiler/coreSyn/CoreUnfold.lhs
@@ -309,7 +309,7 @@ sizeExpr bOMB_OUT_SIZE top_args expr
       | fun `hasKey` buildIdKey   = buildSize
       | fun `hasKey` augmentIdKey = augmentSize
       | otherwise 
-      = case globalIdDetails fun of
+      = case idDetails fun of
          DataConWorkId dc -> conSizeN dc (valArgCount args)
 
          FCallId _    -> sizeN opt_UF_DearOp
@@ -536,6 +536,10 @@ data CallCtxt = BoringCtxt
                                --      => be keener to inline
                -- INVARIANT: ArgCtxt False 0 ==> BoringCtxt
 
+             | ValAppCtxt      -- We're applied to at least one value arg
+                               -- This arises when we have ((f x |> co) y)
+                               -- Then the (f x) has argument 'x' but in a ValAppCtxt
+
              | CaseCtxt        -- We're the scrutinee of a case
                                -- that decomposes its scrutinee
 
@@ -543,6 +547,7 @@ instance Outputable CallCtxt where
   ppr BoringCtxt    = ptext (sLit "BoringCtxt")
   ppr (ArgCtxt _ _) = ptext (sLit "ArgCtxt")
   ppr CaseCtxt             = ptext (sLit "CaseCtxt")
+  ppr ValAppCtxt    = ptext (sLit "ValAppCtxt")
 
 callSiteInline dflags active_inline id lone_variable arg_infos cont_info
   = case idUnfolding id of {
@@ -610,8 +615,8 @@ callSiteInline dflags active_inline id lone_variable arg_infos cont_info
                        = case cont_info of
                            BoringCtxt -> not is_top && n_vals_wanted > 0       -- Note [Nested functions] 
                            CaseCtxt   -> not lone_variable || not is_value     -- Note [Lone variables]
-                           ArgCtxt {} -> n_vals_wanted > 0 
-                               -- See Note [Inlining in ArgCtxt]
+                           ArgCtxt {} -> n_vals_wanted > 0                     -- Note [Inlining in ArgCtxt]
+                           ValAppCtxt -> True                                  -- Note [Cast then apply]
 
                    small_enough = (size - discount) <= opt_UF_UseThreshold
                    discount = computeDiscount n_vals_wanted arg_discounts 
@@ -619,7 +624,7 @@ callSiteInline dflags active_inline id lone_variable arg_infos cont_info
                    res_discount' = case cont_info of
                                        BoringCtxt  -> 0
                                        CaseCtxt    -> res_discount
-                                       ArgCtxt _ _ -> 4 `min` res_discount
+                                       _other      -> 4 `min` res_discount
                        -- res_discount can be very large when a function returns
                        -- construtors; but we only want to invoke that large discount
                        -- when there's a case continuation.
@@ -655,6 +660,16 @@ branches.  Then inlining it doesn't increase allocation, but it does
 increase the chance that the constructor won't be allocated at all in
 the branches that don't use it.
 
+Note [Cast then apply]
+~~~~~~~~~~~~~~~~~~~~~~
+Consider
+   myIndex = __inline_me ( (/\a. <blah>) |> co )
+   co :: (forall a. a -> a) ~ (forall a. T a)
+     ... /\a.\x. case ((myIndex a) |> sym co) x of { ... } ...
+
+We need to inline myIndex to unravel this; but the actual call (myIndex a) has
+no value arguments.  The ValAppCtxt gives it enough incentive to inline.
+
 Note [Inlining in ArgCtxt]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 The condition (n_vals_wanted > 0) here is very important, because otherwise
@@ -669,7 +684,7 @@ slow-down).  The motivation was test eyeball/inline1.hs; but that seems
 to work ok now.
 
 Note [Lone variables]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+~~~~~~~~~~~~~~~~~~~~~
 The "lone-variable" case is important.  I spent ages messing about
 with unsatisfactory varaints, but this is nice.  The idea is that if a
 variable appears all alone