Possible fix to fork split

• Don't count phis and reduces outside a fork join as in a reduce cycle.

hercules_ir/src/loops.rs

@@ -248,6 +248,14 @@ pub fn reduce_cycles(
     for reduce in reduces {
         let (join, _, reduct) = function.nodes[reduce.idx()].try_reduce().unwrap();
         let fork = join_fork_map[&join];
+        let isnt_outside_fork_join = |id: NodeID| {
+            let node = &function.nodes[id.idx()];
+            node.try_phi()
+                .map(|(control, _)| control)
+                .or(node.try_reduce().map(|(control, _, _)| control))
+                .map(|control| fork_join_nest[&fork].contains(&control))
+                .unwrap_or(true)
+        };
 
         // First, find all data nodes that are used by the `reduct` input of the
         // reduce, including the `reduct` itself.
@@ -258,10 +266,7 @@ pub fn reduce_cycles(
             for u in get_uses(&function.nodes[item.idx()]).as_ref() {
                 if !function.nodes[u.idx()].is_control()
                     && !use_reachable.contains(u)
-                    && function.nodes[u.idx()]
-                        .try_phi()
-                        .map(|(control, _)| fork_join_nest[&fork].contains(&control))
-                        .unwrap_or(true)
+                    && isnt_outside_fork_join(*u)
                 {
                     use_reachable.insert(*u);
                     worklist.push(*u);
@@ -274,7 +279,10 @@ pub fn reduce_cycles(
         let mut worklist = vec![reduce];
         while let Some(item) = worklist.pop() {
             for u in def_use.get_users(item) {
-                if !function.nodes[u.idx()].is_control() && !user_reachable.contains(u) {
+                if !function.nodes[u.idx()].is_control()
+                    && !user_reachable.contains(u)
+                    && isnt_outside_fork_join(*u)
+                {
                     user_reachable.insert(*u);
                     worklist.push(*u);
                 }