Consistently treat profile blocks as blocks in optimizer

src/analysis_and_optimization/Dataflow_utils.ml

@@ -137,7 +137,7 @@ let build_cf_graphs ?(flatten_loops = false) ?(blocks_after_body = true)
        is visited after substatements *)
     let substmt_preds =
       match stmt with
-      | Block _ when blocks_after_body -> in_state.exits
+      | (Block _ | Profile _) when blocks_after_body -> in_state.exits
       | _ -> Set.Poly.singleton label in
     (* The accumulated state after traversing substatements *)
     let substmt_state_unlooped, substmt_map =
@@ -174,7 +174,7 @@ let build_cf_graphs ?(flatten_loops = false) ?(blocks_after_body = true)
                   Set.Poly.diff substmt_state_unlooped.breaks in_state.breaks ]
           in
           ({substmt_state_unlooped with exits= loop_exits}, loop_predecessors)
-      | Block _ when blocks_after_body ->
+      | (Block _ | Profile _) when blocks_after_body ->
           (* Block statements are preceded by the natural exit points of the block
              body *)
           let block_predecessors = substmt_state_unlooped.exits in

src/analysis_and_optimization/Mir_utils.ml

@@ -109,7 +109,7 @@ let rec var_declarations Stmt.Fixed.{pattern; _} : string Set.Poly.t =
   | IfElse (_, s, None) | While (_, s) | For {body= s; _} -> var_declarations s
   | IfElse (_, s1, Some s2) ->
       Set.Poly.union (var_declarations s1) (var_declarations s2)
-  | Block slist | SList slist ->
+  | Block slist | SList slist | Profile (_, slist) ->
       Set.Poly.union_list (List.map ~f:var_declarations slist)
   | _ -> Set.Poly.empty
 
@@ -431,6 +431,7 @@ let cleanup_empty_stmts stmts =
   let is_decl = function {pattern= Decl _; _} -> true | _ -> false in
   let flatten_block s =
     match s.pattern with
+    (* NB: Does not include Profile since we don't want to remove those blocks *)
     | SList ls | Block ls ->
         if List.for_all ~f:(Fn.non is_decl) ls then ls else [s]
     | _ -> [s] in

src/middle/Stmt.ml

@@ -51,8 +51,10 @@ module Fixed = struct
       | For {loopvar; lower; upper; body} ->
           Fmt.pf ppf "for(%s in %a:%a) %a" loopvar pp_e lower pp_e upper pp_s
             body
-      | Profile (_, stmts) ->
-          Fmt.pf ppf "{@;<1 2>@[<v>%a@]@;}" Fmt.(list pp_s ~sep:cut) stmts
+      | Profile (name, stmts) ->
+          Fmt.pf ppf "profile(%s){@;<1 2>@[<v>%a@]@;}" name
+            Fmt.(list pp_s ~sep:cut)
+            stmts
       | Block stmts ->
           Fmt.pf ppf "{@;<1 2>@[<v>%a@]@;}" Fmt.(list pp_s ~sep:cut) stmts
       | SList stmts -> Fmt.(list pp_s ~sep:cut |> vbox) ppf stmts

test/integration/good/compiler-optimizations/copy-prop-profile.stan

@@ -0,0 +1,26 @@
+data {
+  int<lower=0> N;
+}
+parameters {
+  matrix[N,N] X;
+}
+
+model {
+  row_vector[N] vec;
+
+  profile ("test") {
+    row_vector[N] vec2 = columns_dot_self(X);
+    vec = vec2;
+  }
+
+  target += sum(vec);
+
+  row_vector[N] vec3;
+  {
+    row_vector[N] vec4 = columns_dot_self(X);
+    vec3 = vec4;
+  }
+
+  target += sum(vec3);
+
+}