inlinenonreptop :: Transform
inlinenonreptop = everywhere ("inlinenonrep", inlinebind ((Monad.liftM not) . isRepr . snd))
+--------------------------------
+-- Top level function inlining
+--------------------------------
+-- This transformation inlines top level bindings that have been generated by
+-- the compiler and are really simple. Really simple currently means that the
+-- normalized form only contains a single binding, which catches most of the
+-- cases where a top level function is created that simply calls a type class
+-- method with a type and dictionary argument, e.g.
+-- fromInteger = GHC.Num.fromInteger (SizedWord D8) $dNum
+-- which is later called using simply
+-- fromInteger (smallInteger 10)
+-- By inlining such calls to simple, compiler generated functions, we prevent
+-- huge amounts of trivial components in the VHDL output, which the user never
+-- wanted. We never inline user-defined functions, since we want to preserve
+-- all structure defined by the user. Currently this includes all functions
+-- that were created by funextract, since we would get loops otherwise.
+--
+-- Note that "defined by the compiler" isn't completely watertight, since GHC
+-- doesn't seem to set all those names as "system names", we apply some
+-- guessing here.
inlinetoplevel, inlinetopleveltop :: Transform
-- Any system name is candidate for inlining. Never inline user-defined
-- functions, to preserve structure.
-- Perform this transform everywhere
scrutsimpltop = everywhere ("scrutsimpl", scrutsimpl)
+--------------------------------
+-- Scrutinee binder removal
+--------------------------------
+-- A case expression can have an extra binder, to which the scrutinee is bound
+-- after bringing it to WHNF. This is used for forcing evaluation of strict
+-- arguments. Since strictness does not matter for us (rather, everything is
+-- sort of strict), this binder is ignored when generating VHDL, and must thus
+-- be wild in the normal form.
+scrutbndrremove, scrutbndrremovetop :: Transform
+-- If the scrutinee is already simple, and the bndr is not wild yet, replace
+-- all occurences of the binder with the scrutinee variable.
+scrutbndrremove (Case (Var scrut) bndr ty alts) | bndr_used = do
+ alts' <- mapM subs_bndr alts
+ return $ Case (Var scrut) wild ty alts'
+ where
+ is_used (_, _, expr) = expr_uses_binders [bndr] expr
+ bndr_used = or $ map is_used alts
+ subs_bndr (con, bndrs, expr) = do
+ expr' <- substitute bndr (Var scrut) expr
+ return (con, bndrs, expr')
+ wild = MkCore.mkWildBinder (Id.idType bndr)
+scrutbndrremovetop = everywhere ("scrutbndrremove", scrutbndrremove)
+
--------------------------------
-- Case binder wildening
--------------------------------
-- What transforms to run?
-transforms = [inlinetopleveltop, argproptop, funextracttop, etatop, betatop, castproptop, letremovesimpletop, letderectop, letremovetop, letsimpltop, letflattop, scrutsimpltop, casesimpltop, caseremovetop, inlinenonreptop, appsimpltop, letremoveunusedtop, castsimpltop, lambdasimpltop, simplrestop]
+transforms = [inlinetopleveltop, argproptop, funextracttop, etatop, betatop, castproptop, letremovesimpletop, letderectop, letremovetop, letsimpltop, letflattop, scrutsimpltop, scrutbndrremovetop, casesimpltop, caseremovetop, inlinenonreptop, appsimpltop, letremoveunusedtop, castsimpltop, lambdasimpltop, simplrestop]
-- | Returns the normalized version of the given function.
getNormalized ::