nak: add is_gpr_reg and is_ugpr_reg helpers

Reviewed-by: Mel Henning <mhenning@darkrefraction.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40891>

src/nouveau/compiler/nak/ir.rs

@@ -1158,6 +1158,24 @@ impl Src {
         }
     }
 
+    #[allow(dead_code)]
+    pub fn is_gpr_reg(&self) -> bool {
+        match &self.src_ref {
+            SrcRef::SSA(ssa) => ssa.file() == RegFile::GPR,
+            SrcRef::Reg(reg) => reg.file() == RegFile::GPR,
+            _ => false,
+        }
+    }
+
+    #[allow(dead_code)]
+    pub fn is_ugpr_reg(&self) -> bool {
+        match &self.src_ref {
+            SrcRef::SSA(ssa) => ssa.file() == RegFile::UGPR,
+            SrcRef::Reg(reg) => reg.file() == RegFile::UGPR,
+            _ => false,
+        }
+    }
+
     pub fn is_predicate(&self) -> bool {
         self.src_ref.is_predicate()
     }