From dfc733c9e5d261411a74a82add97a0028876ebde Mon Sep 17 00:00:00 2001
From: Lex Bailey <lex.bailey+gitcommit@codasip.com>
Date: Mon, 25 Nov 2024 17:23:52 +0000
Subject: [PATCH] bugfix: place_pi_functions now raises error when graph
 contains loop

---
 src/lib/jib_ssa.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lib/jib_ssa.ml b/src/lib/jib_ssa.ml
index 757c0ad40..4ab64f03c 100644
--- a/src/lib/jib_ssa.ml
+++ b/src/lib/jib_ssa.ml
@@ -711,6 +711,7 @@ let place_pi_functions ~start ~finish ~post_idom ~post_df graph =
     if not (IntSet.mem n !visited) then (
       match graph.nodes.(n) with
       | Some ((ssa, cfnode), preds, succs) ->
+          visited := IntSet.add n !visited;
           let disj =
             List.map
               (fun post_frontier ->
@@ -740,7 +741,6 @@ let place_pi_functions ~start ~finish ~post_idom ~post_df graph =
             | [conj] -> Pi conj
             | conjs -> Pi [mk_disj (List.map (fun conj -> mk_conj conj) conjs)]
           in
-          visited := IntSet.add n !visited;
           graph.nodes.(n) <- Some ((mk_pi disj :: ssa, cfnode), preds, succs)
       | None -> ()
     )