[Driver][DXC] Accept -f{no-,}discard-value-names in the DXC driver

Author: bogner

clang/include/clang/Driver/Options.td

@@ -1870,9 +1870,11 @@ defm safe_buffer_usage_suggestions : BoolFOption<"safe-buffer-usage-suggestions"
   PosFlag<SetTrue, [], [ClangOption, CC1Option],
           "Display suggestions to update code associated with -Wunsafe-buffer-usage warnings">,
   NegFlag<SetFalse>>;
-def fdiscard_value_names : Flag<["-"], "fdiscard-value-names">, Group<f_clang_Group>,
+def fdiscard_value_names : Flag<["-"], "fdiscard-value-names">,
+  Group<f_clang_Group>, Visibility<[ClangOption, DXCOption]>,
   HelpText<"Discard value names in LLVM IR">, Flags<[NoXarchOption]>;
-def fno_discard_value_names : Flag<["-"], "fno-discard-value-names">, Group<f_clang_Group>,
+def fno_discard_value_names : Flag<["-"], "fno-discard-value-names">,
+  Group<f_clang_Group>, Visibility<[ClangOption, DXCOption]>,
   HelpText<"Do not discard value names in LLVM IR">, Flags<[NoXarchOption]>;
 defm dollars_in_identifiers : BoolFOption<"dollars-in-identifiers",
   LangOpts<"DollarIdents">, Default<!strconcat("!", asm_preprocessor.KeyPath)>,

clang/test/Driver/dxc_valuenames.hlsl

@@ -0,0 +1,4 @@
+// RUN: %clang_dxc -### -T lib_6_6 -Fc - -fdiscard-value-names %s 2>&1 | FileCheck -check-prefix=CHECK-DISCARD-NAMES %s
+// RUN: %clang_dxc -### -T lib_6_6 -Fc - -fno-discard-value-names %s 2>&1 | FileCheck -check-prefix=CHECK-NO-DISCARD-NAMES %s
+// CHECK-DISCARD-NAMES: "-discard-value-names"
+// CHECK-NO-DISCARD-NAMES-NOT: "-discard-value-names"