Restore support for target profile lib_6_x

Author: bharadwajy

clang/lib/Driver/ToolChains/HLSL.cpp

@@ -135,9 +135,11 @@ std::optional<std::string> tryParseProfile(StringRef Profile) {
     SubArch = llvm::Triple::DXILSubArch_v1_7;
     break;
   case 8:
+  case OfflineLibMinor:
+    // Always consider minor version x as the latest supported minor version
     SubArch = llvm::Triple::DXILSubArch_v1_8;
     break;
-  default :
+  default:
     // No DXIL Version corresponding to specified Shader Model version found
     return std::nullopt;
   }

clang/unittests/Driver/DXCModeTest.cpp

@@ -86,7 +86,7 @@ TEST(DxcModeTest, TargetProfileValidation) {
                         InMemoryFileSystem, Diags);
   validateTargetProfile("-Tas_6_7", "dxilv1.7--shadermodel6.7-amplification",
                         InMemoryFileSystem, Diags);
-  validateTargetProfile("-Tlib_6_8", "dxilv1.8--shadermodel6.8-library",
+  validateTargetProfile("-Tlib_6_x", "dxilv1.8--shadermodel6.15-library",
                         InMemoryFileSystem, Diags);
 
   // Invalid tests.