;; Prelude definitions specific to the mid-end.

;;;;; eclass and enode access ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; An eclass ID.
(type Id (primitive Id))

;; What is the type of an eclass (if a single type)?
(decl eclass_type (Type) Id)
(extern extractor eclass_type eclass_type)

;; Helper to wrap an Id-matching pattern and extract type.
(decl has_type (Type Id) Id)
(extractor (has_type ty id)
           (and (eclass_type ty)
                id))

;; Extract any node(s) for the given eclass ID.
(decl multi enodes (Type InstructionImms IdArray) Id)
(extern extractor enodes enodes_etor)

;; Construct a pure node, returning a new (or deduplicated
;; already-existing) eclass ID.
(decl pure_enode (Type InstructionImms IdArray) Id)
(extern constructor pure_enode pure_enode_ctor)

;; Type of an Id slice (for args).
(type IdArray (primitive IdArray))

(decl id_array_0 () IdArray)
(extern constructor id_array_0 id_array_0_ctor)
(extern extractor id_array_0 id_array_0_etor)
(decl id_array_1 (Id) IdArray)
(extern constructor id_array_1 id_array_1_ctor)
(extern extractor id_array_1 id_array_1_etor)
(decl id_array_2 (Id Id) IdArray)
(extern constructor id_array_2 id_array_2_ctor)
(extern extractor id_array_2 id_array_2_etor)
(decl id_array_3 (Id Id Id) IdArray)
(extern constructor id_array_3 id_array_3_ctor)
(extern extractor id_array_3 id_array_3_etor)

;; Extractor to get the min loop-level of an eclass.
(decl at_loop_level (u8 Id) Id)
(extern extractor infallible at_loop_level at_loop_level)

;;;;; optimization toplevel ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; The main matcher rule invoked by the toplevel driver.
(decl multi simplify (Id) Id)

;; Mark a node as requiring remat when used in a different block.
(decl remat (Id) Id)
(extern constructor remat remat)

;; Mark a node as subsuming whatever else it's rewritten from -- this
;; is definitely preferable, not just a possible option. Useful for,
;; e.g., constant propagation where we arrive at a definite "final
;; answer".
(decl subsume (Id) Id)
(extern constructor subsume subsume)