nak: Handle CS2R latencies in SSA form

Reviewed-by: Mary Guillemard <mary@mary.zone>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38939>

src/nouveau/compiler/nak/ir.rs

@@ -497,6 +497,14 @@ impl Dst {
         }
         .iter_mut()
     }
+
+    pub fn comps(&self) -> u8 {
+        match self {
+            Dst::None => 0,
+            Dst::SSA(ssa) => ssa.comps(),
+            Dst::Reg(reg) => reg.comps(),
+        }
+    }
 }
 
 impl From<RegRef> for Dst {

src/nouveau/compiler/nak/sm75_instr_latencies.rs

@@ -141,7 +141,7 @@ impl RegLatencySM75 {
                 }
             }
             Op::CS2R(cs2r) => {
-                if cs2r.dst.as_reg().unwrap().comps() == 2 {
+                if cs2r.dst.comps() == 2 {
                     CoupledDisp64
                 } else {
                     CoupledAlu

src/nouveau/compiler/nak/sm80_instr_latencies.rs

@@ -186,7 +186,7 @@ impl RegLatencySM80 {
                 }
             }
             Op::CS2R(cs2r) => {
-                if cs2r.dst.as_reg().unwrap().comps() == 2 {
+                if cs2r.dst.comps() == 2 {
                     CoupledDisp64
                 } else {
                     CoupledAlu