diff --git a/lang/src/backend/hbvm.rs b/lang/src/backend/hbvm.rs
index 970785c..b2b61fc 100644
--- a/lang/src/backend/hbvm.rs
+++ b/lang/src/backend/hbvm.rs
@@ -438,7 +438,7 @@ impl Nodes {
         ((node.kind == Kind::Stre && node.inputs[2] == target)
             || (node.kind == Kind::Load && node.inputs[1] == target))
             && (node.ty.loc(tys) == Loc::Reg
-                // this means the struct is actually loaded into a register so no BMC needed
+               //  this means the struct is actually loaded into a register so no BMC needed
                 || (node.kind == Kind::Load
                     && !matches!(tys.parama(node.ty).0, Some(PLoc::Ref(..)))
                     && node.outputs.iter().all(|&o| matches!(self[o].kind, Kind::Call { .. } | Kind::Return { .. }))))
@@ -643,7 +643,7 @@ impl TokenKind {
     }
 }
 
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Debug)]
 enum PLoc {
     Reg(Reg, u16),
     WideReg(Reg, u16),
diff --git a/lang/src/backend/hbvm/regalloc.rs b/lang/src/backend/hbvm/regalloc.rs
index 0a5723e..ce67e1d 100644
--- a/lang/src/backend/hbvm/regalloc.rs
+++ b/lang/src/backend/hbvm/regalloc.rs
@@ -121,9 +121,10 @@ impl HbvmBackend {
                             || nodes.is_hard_zero(allc)
                             || allc == MEM
                             || matches!(node.kind, Kind::Loop | Kind::Region),
-                        "{nid} {:?}\n{allc} {:?}",
+                        "{nid} {:?}\n{allc} {:?} {}",
                         nodes[nid],
-                        nodes[allc]
+                        nodes[allc],
+                        ty::Display::new(tys, files, nodes[allc].ty)
                     );
                 };
 
@@ -712,10 +713,6 @@ impl Nodes {
                 );
                 self[user].inputs.iter().position(|&v| v == val).is_some_and(|v| v < 3)
             }
-            //Kind::Call { .. } => {
-            //    self[val].kind != Kind::Load
-            //        || matches!(types.parama(self[val].ty).0, Some(PLoc::Ref(..)))
-            //}
             Kind::Load => self[user].inputs[2] != val,
             _ => self[user].inputs[0] != val || self[user].inputs[1..].contains(&val),
         }
@@ -761,19 +758,22 @@ impl Nodes {
             return None.into_iter().flatten();
         }
 
-        Some(
-            self[nid]
-                .outputs
-                .iter()
-                .filter(move |&&n| self.is_data_dep(nid, n, types))
-                .map(move |n| self.this_or_delegates(nid, n))
-                .flat_map(|(p, ls)| ls.iter().map(move |l| (p, l)))
-                .filter(|&(o, &n)| self.is_data_dep(o, n, types))
-                .map(|(p, &n)| (self.use_block_of(p, n), n))
-                .inspect(|&(_, n)| debug_assert!(self.is_unlocked(n))),
-        )
-        .into_iter()
-        .flatten()
+        let mut uses = vec![];
+        let mut to_expand = vec![nid];
+        while let Some(exp) = to_expand.pop() {
+            for &o in self[exp].outputs.iter() {
+                if !self.is_data_dep(exp, o, types) {
+                    continue;
+                }
+                if self.is_unlocked(o) {
+                    uses.push((self.use_block_of(exp, o), o));
+                } else {
+                    to_expand.push(o);
+                }
+            }
+        }
+
+        Some(uses).into_iter().flatten()
     }
 }