--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/llvm/test/TableGen/isa.td	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,39 @@
+// RUN: llvm-tblgen %s | FileCheck %s
+// XFAIL: vg_leak
+
+// CHECK: --- Defs ---
+
+// CHECK: def X0 {
+// CHECK:   int ret = 0;
+// CHECK: }
+
+// CHECK: def X1 {
+// CHECK:   int ret = 1;
+// CHECK: }
+
+// CHECK: def Y0 {
+// CHECK:   int ret = 0;
+// CHECK: }
+
+// CHECK: def Y1 {
+// CHECK:   int ret = 11;
+// CHECK: }
+
+class A<int dummy>;
+class B<int num> : A<num> {
+  int Num = num;
+}
+
+class X<A a> {
+  int ret = !isa<B>(a);
+}
+
+class Y<A a> {
+  int ret = !if(!isa<B>(a), !cast<B>(a).Num, 0);
+}
+
+def X0 : X<A<0>>;
+def X1 : X<B<0>>;
+
+def Y0 : Y<A<10>>;
+def Y1 : Y<B<11>>;