#14844: SpecConstr also non-recursive function -------------------------------------+------------------------------------- Reporter: nomeata | Owner: (none) Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.5 Resolution: | Keywords: SpecConstr Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by nomeata): So here is an idea that might help here, and that I want to run past people who know !SpecConstr well (is that anyone else but SPJ at this point?). Status quo: `l` gets specialized, because of the two call patterns `s' t0` and `(s-1) (x,y)`, the second one is interesting *and* its second argument gets scrutinized (the `scu_occs` field reports `ScrutOcc` for `t`). But `foo` does not get specialized: It does have an interesting call pattern, but `scu_occs` reports `UnkOcc`, because `foo`’s parameters are just passed to `t`. But: When we decide to !SpecConstr `l`, we know that one of the calls to to `l` is of the shape `s' t0`. This is a boring call, and we do not create a specialization for it. But we create a specialization for `l` using the the other call pattern. This means we know that it would be beneficial if `t0` were a constructor. So can we, at this point, decide to include `t0 ↦ ScrutOcc` in `scu_occs`? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14844#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler