nak: Use Default::default() for BitSet constructors

Reviewed-by: Mel Henning <mhenning@darkrefraction.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34994>

src/nouveau/compiler/nak/assign_regs.rs

@@ -271,8 +271,8 @@ impl RegAllocator {
         Self {
             file: file,
             num_regs: num_regs,
-            used: BitSet::new(),
-            pinned: BitSet::new(),
+            used: Default::default(),
+            pinned: Default::default(),
             reg_ssa: Vec::new(),
             ssa_reg: Default::default(),
         }

src/nouveau/compiler/nak/liveness.rs

@@ -227,6 +227,7 @@ pub trait Liveness {
     }
 }
 
+#[derive(Default)]
 pub struct SimpleBlockLiveness {
     defs: BitSet,
     uses: BitSet,
@@ -237,13 +238,7 @@ pub struct SimpleBlockLiveness {
 
 impl SimpleBlockLiveness {
     fn new() -> Self {
-        Self {
-            defs: BitSet::new(),
-            uses: BitSet::new(),
-            last_use: Default::default(),
-            live_in: BitSet::new(),
-            live_out: BitSet::new(),
-        }
+        Default::default()
     }
 
     fn add_def(&mut self, ssa: SSAValue) {

src/nouveau/compiler/nak/opt_bar_prop.rs

@@ -48,6 +48,7 @@ impl PhiMap {
     }
 }
 
+#[derive(Default)]
 struct BarPropPass {
     ssa_map: FxHashMap<SSAValue, SSAValue>,
     phi_is_bar: BitSet,
@@ -56,11 +57,7 @@ struct BarPropPass {
 
 impl BarPropPass {
     pub fn new() -> BarPropPass {
-        BarPropPass {
-            ssa_map: Default::default(),
-            phi_is_bar: BitSet::new(),
-            phi_is_not_bar: BitSet::new(),
-        }
+        Default::default()
     }
 
     fn add_copy(&mut self, dst: SSAValue, src: SSAValue) {