[project @ 1999-07-06 16:45:31 by simonpj]

All Simon's recent tuning changes.  Rough summary follows:

* Fix Kevin Atkinson's cant-find-instance bug.  Turns out that Rename.slurpSourceRefs
  needs to repeatedly call getImportedInstDecls, and then go back to slurping
  source-refs.  Comments with Rename.slurpSourceRefs.

* Add a case to Simplify.mkDupableAlt for the quite-common case where there's
  a very simple alternative, in which case there's no point in creating a
  join-point binding.

* Fix CoreUtils.exprOkForSpeculation so that it returns True of (==# a# b#).
  This lack meant that
	case ==# a# b# of { True -> x; False -> x }
  was not simplifying

* Make float-out dump bindings at the top of a function argument, as
  at the top of a let(rec) rhs.  See notes with FloatOut.floatRhs

* Make the ArgOf case of mkDupableAlt generate a OneShot lambda.
  This gave a noticeable boost to spectral/boyer2


* Reduce the number of coerces, using worker/wrapper stuff.
  The main idea is in WwLib.mkWWcoerce.  The gloss is that we must do
  the w/w split even for small non-recursive things.  See notes with
  WorkWrap.tryWw.

* This further complicated getWorkerId, so I finally bit the bullet and
  make the workerInfo field of the IdInfo work properly, including
  under substitutions.  Death to getWorkerId.  Kevin Glynn will be happy.

* Make all lambdas over realWorldStatePrimTy
  into one-shot lambdas.  This is a GROSS HACK.

* Also make the occurrence analyser aware of one-shot lambdas.

* Make various Prelude things into INLINE, so that foldr doesn't
  get inlined in their body, so that the caller gets the benefit
  of fusion.  Notably in PrelArr.lhs.

1 files changed, 13 insertions, 1 deletions

diff --git a/ghc/compiler/specialise/Rules.lhs b/ghc/compiler/specialise/Rules.lhs
index 99da2e2d70..8406b0a498 100644
--- a/ghc/compiler/specialise/Rules.lhs
+++ b/ghc/compiler/specialise/Rules.lhs
@@ -159,7 +159,17 @@ matchRule in_scope (Rule rn tpl_vars tpl_args rhs) args
 
 	-- One tiresome way to terminate: check for excess unmatched
 	-- template arguments
-   go tpl_args		 []	    subst 
+   go tpl_args		 []	    subst = Nothing	-- Failure
+
+
+{-	The code below tries to match even if there are more 
+	template args than real args.
+
+	I now think this is probably a bad idea.
+	Should the template (map f xs) match (map g)?  I think not.
+	For a start, in general eta expansion wastes work.
+	SLPJ July 99
+
       = case eta_complete tpl_args (mkVarSet leftovers) of
 	    Just leftovers' -> Just (rn, mkLams done (mkLams leftovers' rhs), 
 				     mk_result_args subst done)
@@ -188,6 +198,7 @@ matchRule in_scope (Rule rn tpl_vars tpl_args rhs) args
 		Nothing    -> Nothing
 
    eta_complete other vars = Nothing
+-}
 
    -----------------------
    mk_result_args subst vs = map go vs
@@ -198,6 +209,7 @@ matchRule in_scope (Rule rn tpl_vars tpl_args rhs) args
 			Just (DoneTy ty) -> Type ty
 			-- Substitution should bind them all!
 
+
 zapOccInfo bndr | isTyVar bndr = bndr
 		| otherwise    = maybeModifyIdInfo zapLamIdInfo bndr
 \end{code}