More type functions ~~~~~~~~~~~~~~~~~~~ * Allow {tv = TYPE ty) as a non-rec binding in Core * Use this to make equality constraints more uniform * Can a Dict can contain an EqPred? How does that differ from an EqInst? * Make DictBinds into Core * In zonking, do we need to zonk the kinds of coercion variables? Type functions ~~~~~~~~~~~~~~ * A Given inst should be a CoVar, not a coercion * finaliseEqInst should not need to call zonk * Why do we need fromGivenEqDict? How could we construct a Dict that had an EqPred? newDictBndr should make an EqInst directly * tc_co should be accessed only inside Inst * Inst.mkImplicTy needs a commment about filtering out EqInsts How *do* we deal with wanted equalities? * Inst.instType behaves inconsistently for EqInsts: it should return an EqPred, like the instType' hack in pprDictsTheta Consequences: adjust the uses of instType in TcSimplify * tcDeref* functions are unused, except in tcGenericNormalizeFamInst, when we can equally well use TcMType.lookupTcTyVar * Coercion.mkEqPredCoI looks very peculiar. ------------------------- *** unexpected failure for jtod_circint(opt) New back end thoughts ----------------------------------------------------------------------------- Codegen notes * jumps to ImpossibleBranch should be removed. * Profiling: - when updating a closure with an indirection to a function, we should make a permanent indirection. - check that we're bumping the scc count appropriately * check perf & binary sizes against the HEAD ----------------------------------------------------------------------------- C backend notes * use STGCALL macros for foreign calls (doesn't look like volatile regs are handled properly at the mo). ----------------------------------------------------------------------------- Cmm parser notes * switches * need to cater for unexported procedures/info tables? * We should be able to get rid of entry labels, use info labels only. - we need a %ENTRY_LBL(info_lbl) macro, so that instead of JMP_(foo_entry) we can write jump %ENTRY_LBL(foo_info). ----------------------------------------------------------------------------- * Move arg-descr from LFInfo to ClosureInfo? But: only needed for functions * Move all of CgClosure.link_caf into NewCaf, and newDynCaf * If the case binder is dead, and the constr is nullary, do we need to assign to Node? ------------------------------- NB: all floats are let-binds, but some non-rec lets may be unlifted (with RHS ok-for-speculation) simplArg: [use strictness] [used for non-top-lvl non-rec RHS or function arg] if strict-type || demanded simplStrictExpr else simplExpr ---> (floats,expr) float all the floats if exposes constr app, return expr simpl (applied lambda) ==> simplNonRecBind simpl (Let (NonRec ...) ..) ==> simplNonRecBind simpl (Let (Rec ...) ..) ==> simplRecBind simplRecBind: simplify binders (but not its IdInfo) simplify the pairs one at a time using simplRecPair simplNonRecBind: [was simplBeta] [used for non-top-lvl non-rec bindings] - check for PreInlineUnconditionally - simplify binder, including its IdInfo - simplArg - if strict-type addCaseBind [which makes a let if ok-for-spec] else completeLazyBind simplLazyBind: [binder already simplified, but not its IdInfo] [used for both rec and top-lvl non-rec] [must not be strict/unboxed; case not allowed] - check for PreInlineUnconditionally - substituteIdInfo and add result to in-scope [so that rules are available in rec rhs] - simplExpr --> (floats,expr) - float: lifted floats only if exposes constructor or pap (even if non-triv args) or if top level - completeLazyBind completeLazyBind: [given a simplified RHS] [used for both rec and non-rec bindings, top level and not] - try discarding dead - try PostInlineUnconditionally - let-bind coerce arg and repeat - try rhs tylam (float) - try eta expand (float) [not if any float is unlifted && (non-spec || top_lvl || rec)] - let-bind constructor args [not if any float is ..as above..] - add unfolding [this is the only place we add an unfolding] add arity Eta expansion ~~~~~~~~~~~~~~ For eta expansion, we want to catch things like case e of (a,b) -> \x -> case a of (p,q) -> \y -> r If the \x was on the RHS of a let, we'd eta expand to bring the two lambdas together. And in general that's a good thing to do. Perhaps we should eta expand wherever we find a (value) lambda? Then the eta expansion at a let RHS can concentrate solely on the PAP case.