Add a couple of additional tests per PR feedback

Author: bharadwajy

llvm/unittests/TargetParser/TripleTest.cpp

@@ -1025,6 +1025,18 @@ TEST(TripleTest, ParsedIDs) {
   EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
   EXPECT_EQ(Triple::UnknownOS, T.getOS());
 
+  T = Triple("dxilv1.9-unknown-unknown");
+  EXPECT_EQ(Triple::dxil, T.getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.getSubArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::UnknownOS, T.getOS());
+
+  T = Triple("dxil-unknown-unknown");
+  EXPECT_EQ(Triple::dxil, T.getArch());
+  EXPECT_EQ(Triple::NoSubArch, T.getSubArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::UnknownOS, T.getOS());
+
   T = Triple("xtensa");
   EXPECT_EQ(Triple::xtensa, T.getArch());
   EXPECT_EQ(Triple::UnknownVendor, T.getVendor());