Improve handling of inline pragmas, esp where type applications are involved

See the definition of splitInlineCont for what this is about.
Cures Trac #1627.
Test is simpl017

diff --git a/compiler/simplCore/SimplUtils.lhs b/compiler/simplCore/SimplUtils.lhs
index 1399870..a1a7c14 100644 (file)
--- a/compiler/simplCore/SimplUtils.lhs
+++ b/compiler/simplCore/SimplUtils.lhs
@@ -15,7 +15,7 @@ module SimplUtils (
        -- The continuation type
        SimplCont(..), DupFlag(..), LetRhsFlag(..), 
        contIsDupable, contResultType, contIsTrivial, contArgs, dropArgs, 
-       countValArgs, countArgs,
+       countValArgs, countArgs, splitInlineCont,
        mkBoringStop, mkLazyArgStop, mkRhsStop, contIsRhsOrArg,
        interestingCallContext, interestingArgContext,
 
@@ -42,7 +42,8 @@ import Id
 import Var     ( isCoVar )
 import NewDemand
 import SimplMonad
-import Type
+import Type    ( Type, funArgTy, mkForAllTys, mkTyVarTys, 
+                 splitTyConApp_maybe, tyConAppArgs )
 import TyCon
 import DataCon
 import Unify   ( dataConCannotMatch )
@@ -154,10 +155,11 @@ mkLazyArgStop ty has_rules = Stop ty AnArg (canUpdateInPlace ty || has_rules)
 mkRhsStop :: OutType -> SimplCont
 mkRhsStop ty = Stop ty AnRhs (canUpdateInPlace ty)
 
-contIsRhsOrArg (Stop {})       = True
-contIsRhsOrArg (StrictBind {}) = True
-contIsRhsOrArg (StrictArg {})  = True
-contIsRhsOrArg other          = False
+-------------------
+contIsRhsOrArg (Stop {})                = True
+contIsRhsOrArg (StrictBind {})          = True
+contIsRhsOrArg (StrictArg {})           = True
+contIsRhsOrArg other            = False
 
 -------------------
 contIsDupable :: SimplCont -> Bool
@@ -204,6 +206,26 @@ dropArgs :: Int -> SimplCont -> SimplCont
 dropArgs 0 cont = cont
 dropArgs n (ApplyTo _ _ _ cont) = dropArgs (n-1) cont
 dropArgs n other               = pprPanic "dropArgs" (ppr n <+> ppr other)
+
+--------------------
+splitInlineCont :: SimplCont -> Maybe (SimplCont, SimplCont)
+-- Returns Nothing if the continuation should dissolve an InlineMe Note
+-- Return Just (c1,c2) otherwise, 
+--     where c1 is the continuation to put inside the InlineMe 
+--     and   c2 outside
+
+-- Example: (__inline_me__ (/\a. e)) ty
+--     Here we want to do the beta-redex without dissolving the InlineMe
+-- See test simpl017 (and Trac #1627) for a good example of why this is important
+
+splitInlineCont (ApplyTo dup (Type ty) se c)
+  | Just (c1, c2) <- splitInlineCont c                 = Just (ApplyTo dup (Type ty) se c1, c2)
+splitInlineCont cont@(Stop ty _ _)             = Just (mkBoringStop ty, cont)
+splitInlineCont cont@(StrictBind bndr _ _ se _) = Just (mkBoringStop (substTy se (idType bndr)), cont)
+splitInlineCont cont@(StrictArg _ fun_ty _ _)   = Just (mkBoringStop (funArgTy fun_ty), cont)
+splitInlineCont other                          = Nothing
+       -- NB: the calculation of the type for mkBoringStop is an annoying
+       --     duplication of the same calucation in mkDupableCont
 \end{code}
 
 

diff --git a/compiler/simplCore/Simplify.lhs b/compiler/simplCore/Simplify.lhs
index 5142632..5d40071 100644 (file)
--- a/compiler/simplCore/Simplify.lhs
+++ b/compiler/simplCore/Simplify.lhs
@@ -892,10 +892,10 @@ simplNote env (SCC cc) e cont
 
 -- See notes with SimplMonad.inlineMode
 simplNote env InlineMe e cont
-  | contIsRhsOrArg cont                -- Totally boring continuation; see notes above
+  | Just (inside, outside) <- splitInlineCont cont  -- Boring boring continuation; see notes above
   = do {                       -- Don't inline inside an INLINE expression
-         e' <- simplExpr (setMode inlineMode env) e
-       ; rebuild env (mkInlineMe e') cont }
+         e' <- simplExprC (setMode inlineMode env) e inside
+       ; rebuild env (mkInlineMe e') outside }
 
   | otherwise          -- Dissolve the InlineMe note if there's
                -- an interesting context of any kind to combine with