nak: Add tests for OpPopC and enable SrcMod::BNot

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30402>

src/nouveau/compiler/nak/hw_tests.rs

@@ -784,6 +784,19 @@ fn test_op_lop3() {
     }
 }
 
+#[test]
+fn test_op_popc() {
+    let src_mods = [SrcMod::None, SrcMod::BNot];
+    for src_mod in src_mods {
+        let mut op = OpPopC {
+            dst: Dst::None,
+            src: 0.into(),
+        };
+        op.src.src_mod = src_mod;
+        test_foldable_op(op);
+    }
+}
+
 #[test]
 fn test_op_shf() {
     let sm = &RunSingleton::get().sm;

src/nouveau/compiler/nak/ir.rs

@@ -4529,15 +4529,23 @@ impl DisplayOp for OpPSetP {
 }
 
 #[repr(C)]
-#[derive(SrcsAsSlice, DstsAsSlice)]
+#[derive(Clone, SrcsAsSlice, DstsAsSlice)]
 pub struct OpPopC {
     #[dst_type(GPR)]
     pub dst: Dst,
 
-    #[src_type(ALU)]
+    #[src_type(B32)]
     pub src: Src,
 }
 
+impl Foldable for OpPopC {
+    fn fold(&self, _sm: &dyn ShaderModel, f: &mut OpFoldData<'_>) {
+        let src = f.get_u32_bnot_src(self, &self.src);
+        let dst = src.count_ones();
+        f.set_u32_dst(self, &self.dst, dst);
+    }
+}
+
 impl DisplayOp for OpPopC {
     fn fmt_op(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "popc {}", self.src,)