Overhaul Aliases_of_canonical_element; add Alias_set

Also return Bottom from more places (generally anything involved in a
meet).

Author: lukemaurer

.depend

@@ -6002,6 +6002,7 @@ middle_end/flambda/simplify/common_subexpression_elimination.cmo : \
     middle_end/flambda/compilenv_deps/flambda_features.cmi \
     middle_end/flambda/basic/continuation_extra_params_and_args.cmi \
     middle_end/flambda/basic/apply_cont_rewrite_id.cmi \
+    middle_end/flambda/types/env/aliases.cmi \
     middle_end/flambda/simplify/common_subexpression_elimination.cmi
 middle_end/flambda/simplify/common_subexpression_elimination.cmx : \
     middle_end/flambda/compilenv_deps/variable.cmx \
@@ -6019,6 +6020,7 @@ middle_end/flambda/simplify/common_subexpression_elimination.cmx : \
     middle_end/flambda/compilenv_deps/flambda_features.cmx \
     middle_end/flambda/basic/continuation_extra_params_and_args.cmx \
     middle_end/flambda/basic/apply_cont_rewrite_id.cmx \
+    middle_end/flambda/types/env/aliases.cmx \
     middle_end/flambda/simplify/common_subexpression_elimination.cmi
 middle_end/flambda/simplify/common_subexpression_elimination.cmi : \
     middle_end/flambda/basic/simple.cmi \
@@ -9008,7 +9010,6 @@ middle_end/flambda/types/type_descr.rec.cmo : \
     utils/misc.cmi \
     middle_end/flambda/cmx/ids_for_export.cmi \
     middle_end/flambda/compilenv_deps/flambda_colours.cmi \
-    middle_end/flambda/compilenv_deps/coercion.cmi \
     utils/clflags.cmi \
     middle_end/flambda/types/env/aliases.cmi \
     middle_end/flambda/types/type_descr.rec.cmi
@@ -9027,7 +9028,6 @@ middle_end/flambda/types/type_descr.rec.cmx : \
     utils/misc.cmx \
     middle_end/flambda/cmx/ids_for_export.cmx \
     middle_end/flambda/compilenv_deps/flambda_colours.cmx \
-    middle_end/flambda/compilenv_deps/coercion.cmx \
     utils/clflags.cmx \
     middle_end/flambda/types/env/aliases.cmx \
     middle_end/flambda/types/type_descr.rec.cmi
@@ -9296,6 +9296,8 @@ middle_end/flambda/types/basic/var_within_closure_set.cmi : \
 middle_end/flambda/types/env/aliases.cmo : \
     middle_end/flambda/compilenv_deps/variable.cmi \
     middle_end/flambda/basic/simple.cmi \
+    middle_end/flambda/compilenv_deps/reg_width_things.cmi \
+    middle_end/flambda/types/basic/or_bottom.cmi \
     middle_end/flambda/naming/name_mode.cmi \
     middle_end/flambda/basic/name.cmi \
     utils/misc.cmi \
@@ -9308,6 +9310,8 @@ middle_end/flambda/types/env/aliases.cmo : \
 middle_end/flambda/types/env/aliases.cmx : \
     middle_end/flambda/compilenv_deps/variable.cmx \
     middle_end/flambda/basic/simple.cmx \
+    middle_end/flambda/compilenv_deps/reg_width_things.cmx \
+    middle_end/flambda/types/basic/or_bottom.cmx \
     middle_end/flambda/naming/name_mode.cmx \
     middle_end/flambda/basic/name.cmx \
     utils/misc.cmx \
@@ -9319,6 +9323,7 @@ middle_end/flambda/types/env/aliases.cmx : \
     middle_end/flambda/types/env/aliases.cmi
 middle_end/flambda/types/env/aliases.cmi : \
     middle_end/flambda/basic/simple.cmi \
+    middle_end/flambda/types/basic/or_bottom.cmi \
     middle_end/flambda/naming/name_mode.cmi \
     middle_end/flambda/basic/name.cmi \
     middle_end/flambda/cmx/contains_ids.cmo \

compilerlibs/Makefile.compilerlibs

@@ -224,6 +224,7 @@ MIDDLE_END_FLAMBDA_BASIC=\
   middle_end/flambda/basic/coeffects.cmo \
   middle_end/flambda/basic/effects.cmo \
   middle_end/flambda/basic/export_id.cmo \
+  middle_end/flambda/types/basic/or_bottom.cmo \
   middle_end/flambda/types/basic/or_unknown.cmo \
   middle_end/flambda/terms/flambda_primitive.cmo \
   middle_end/flambda/basic/recursive.cmo \
@@ -260,7 +261,6 @@ MIDDLE_END_FLAMBDA_TYPES=\
   middle_end/flambda/types/env/binding_time.cmo \
   middle_end/flambda/types/env/aliases.cmo \
   middle_end/flambda/types/basic/meet_or_join_op.cmo \
-  middle_end/flambda/types/basic/or_bottom.cmo \
   middle_end/flambda/types/basic/string_info.cmo \
   middle_end/flambda/types/basic/or_unknown_or_bottom.cmo \
   middle_end/flambda/types/structures/code_age_relation.cmo \

middle_end/flambda/basic/kinded_parameter.ml

@@ -115,8 +115,6 @@ module List = struct
 
   let name_set t = Name.Set.of_list (List.map Name.var (vars t))
 
-  let simple_set t = Simple.Set.of_list (simples t)
-
   let rename t = List.map (fun t -> rename t) t
 
   let arity t = List.map (fun t -> Flambda_kind.With_subkind.kind (kind t)) t

middle_end/flambda/basic/kinded_parameter.mli

@@ -68,8 +68,6 @@ module List : sig
   (** As for [var_set] but returns a set of [Name]s. *)
   val name_set : t -> Name.Set.t
 
-  val simple_set : t -> Simple.Set.t
-
   val equal_vars : t -> Variable.t list -> bool
 
   val rename : t -> t

middle_end/flambda/compilenv_deps/coercion.ml

@@ -43,7 +43,7 @@ let print ppf = function
       (Flambda_colours.coercion ())
       from_depth to_depth
       (Flambda_colours.normal ())
-    
+
 let compose t1 ~then_:t2 =
   match t1, t2 with
   | Id, _ -> Some t2

middle_end/flambda/compilenv_deps/coercion.mli

@@ -24,12 +24,19 @@ type t = private
 val change_depth : from:int -> to_:int -> t
 
 val id : t
+
 val is_id : t -> bool
+
 val inverse : t -> t
+
 val compose : t -> then_:t -> t option
+
 val compose_exn : t -> then_:t -> t
+
 val print : Format.formatter -> t -> unit
+
 val equal : t -> t -> bool
+
 val hash : t -> int
 
 val apply_to_rec_info : t -> Rec_info.t -> Rec_info.t

middle_end/flambda/compilenv_deps/flambda_colours.ml

@@ -57,7 +57,7 @@ let name_abstraction () = C.fg_256 172
 
 let rec_info () = C.fg_256 249
 
-let coercion () = C.fg_256 243
+let coercion () = C.fg_256 249
 
 let error () = C.fg_256 160
 

middle_end/flambda/compilenv_deps/reg_width_things.mli

@@ -158,6 +158,8 @@ module Simple : sig
 
   val with_coercion : t -> Coercion.t -> t
 
+  (* CR lmaurer: Should make [name] and [const] take a [coercion] argument to
+     be sure we're not dropping coercions by accident. *)
   val pattern_match
      : t
     -> name:(Name.t -> 'a)

middle_end/flambda/simplify/common_subexpression_elimination.ml

@@ -117,7 +117,12 @@ end
 
 let cse_with_eligible_lhs ~typing_env_at_fork ~cse_at_each_use ~params prev_cse
       (extra_bindings: EPA.t) extra_equations =
-  let params = KP.List.simple_set params in
+  let params = KP.List.name_set params in
+  let is_param simple =
+    Simple.pattern_match simple
+      ~name:(fun name -> Name.Set.mem name params)
+      ~const:(fun _ -> false)
+  in
   List.fold_left cse_at_each_use ~init:EP.Map.empty
     ~f:(fun eligible (env_at_use, id, cse) ->
       let find_new_name =
@@ -182,15 +187,17 @@ let cse_with_eligible_lhs ~typing_env_at_fork ~cse_at_each_use ~params prev_cse
                  since they are defined in [env_at_fork].  However these
                  aren't bound at the use sites, so we must choose another
                  alias that is. *)
-              if not (Simple.Set.mem bound_to params) then Some bound_to
+              if not (is_param bound_to) then Some bound_to
               else
                 let aliases =
                   TE.aliases_of_simple env_at_use
                     ~min_name_mode:NM.normal bound_to
-                  |> Simple.Map.filter (fun simple _coercion ->
-                    not (Simple.Set.mem simple params))
+                  |> Aliases.Alias_set.filter ~f:(fun simple ->
+                    not (is_param simple))
                 in
-                Simple.Map.get_singleton aliases |> Option.map fst
+                (* CR lmaurer: This could be using
+                   [Aliases.Alias_set.find_best], I think? *)
+                Aliases.Alias_set.get_singleton aliases
             in
             match bound_to with
             | None -> eligible