diff --git a/src/nouveau/compiler/nak_ir.rs b/src/nouveau/compiler/nak_ir.rs
index a2914b1bae5..1de9e4127c7 100644
--- a/src/nouveau/compiler/nak_ir.rs
+++ b/src/nouveau/compiler/nak_ir.rs
@@ -497,6 +497,10 @@ impl SSAValueAllocator {
         SSAValueAllocator { count: 0 }
     }
 
+    pub fn max_idx(&self) -> u32 {
+        self.count
+    }
+
     pub fn alloc(&mut self, file: RegFile) -> SSAValue {
         self.count += 1;
         SSAValue::new(file, self.count)
diff --git a/src/nouveau/compiler/nak_liveness.rs b/src/nouveau/compiler/nak_liveness.rs
index 449abd4772f..86230f83024 100644
--- a/src/nouveau/compiler/nak_liveness.rs
+++ b/src/nouveau/compiler/nak_liveness.rs
@@ -311,6 +311,10 @@ impl SimpleLiveness {
         assert!(l.blocks.len() == func.blocks.len());
         assert!(live_in.len() == func.blocks.len());
 
+        let num_ssa = usize::try_from(func.ssa_alloc.max_idx() + 1).unwrap();
+        let mut tmp = BitSet::new();
+        tmp.reserve(num_ssa);
+
         let mut to_do = true;
         while to_do {
             to_do = false;
@@ -320,10 +324,13 @@ impl SimpleLiveness {
                     to_do |= bl.live_out.union_with(&live_in[*sb_idx]);
                 }
 
-                let new_live_in =
-                    (bl.live_out.clone() | bl.uses.clone()) & !bl.defs.clone();
+                tmp.clear();
+                tmp.set_words(0..num_ssa, |w| {
+                    (bl.live_out.get_word(w) | bl.uses.get_word(w))
+                        & !bl.defs.get_word(w)
+                });
 
-                to_do |= live_in[b_idx].union_with(&new_live_in);
+                to_do |= live_in[b_idx].union_with(&tmp);
             }
         }