Fork fission

hercules_opt/src/fork_transforms.rs

@@ -310,23 +310,33 @@ pub fn fork_fission<'a>(
     reduce_cycles: &HashMap<NodeID, HashSet<NodeID>>,
     loop_tree: &LoopTree,
     fork_join_map: &HashMap<NodeID, NodeID>,
+    fork_label: LabelID,
 ) -> Vec<NodeID> {
-    let mut forks: Vec<_> = loop_tree
+    let forks: Vec<_> = loop_tree
         .bottom_up_loops()
         .into_iter()
         .filter(|(k, _)| editor.func().nodes[k.idx()].is_fork())
         .collect();
 
     let mut created_forks = Vec::new();
+    
     // This does the reduction fission 
-    for fork in forks.clone() {
+    for fork in forks {
         let join = fork_join_map[&fork.0];
+
+        // FIXME: Don't make multiple forks for reduces that are in cycles with each other. 
         let reduce_partition = default_reduce_partition(editor, fork.0, join);
 
+        if !editor.func().labels[fork.0.idx()].contains(&fork_label) {
+            continue;
+        }
+
         if editor.is_mutable(fork.0) {
             created_forks = fork_reduce_fission_helper(editor, fork_join_map, reduce_partition, nodes_in_fork_joins, fork.0);
-            if !created_forks.is_empty() {
-                break;
+            if created_forks.is_empty() {
+                continue;
+            } else {
+                return created_forks;
             }
         }