clang-cl: Expose -fmerge-all-constants

Now that constant merging is off by default, we'd like a way to enable
it on Windows.

llvm-svn: 331214

Author: zmodem

clang/include/clang/Driver/Options.td

@@ -1176,7 +1176,7 @@ def fthinlto_index_EQ : Joined<["-"], "fthinlto-index=">,
 def fmacro_backtrace_limit_EQ : Joined<["-"], "fmacro-backtrace-limit=">,
                                 Group<f_Group>, Flags<[DriverOption, CoreOption]>;
 def fmerge_all_constants : Flag<["-"], "fmerge-all-constants">, Group<f_Group>,
-  Flags<[CC1Option]>, HelpText<"Allow merging of constants">;
+  Flags<[CC1Option, CoreOption]>, HelpText<"Allow merging of constants">;
 def fmessage_length_EQ : Joined<["-"], "fmessage-length=">, Group<f_Group>;
 def fms_extensions : Flag<["-"], "fms-extensions">, Group<f_Group>, Flags<[CC1Option, CoreOption]>,
   HelpText<"Accept some non-standard constructs supported by the Microsoft compiler">;

clang/test/Driver/cl-options.c

@@ -590,6 +590,7 @@
 // RUN:     -fstandalone-debug \
 // RUN:     -flimit-debug-info \
 // RUN:     -flto \
+// RUN:     -fmerge-all-constants \
 // RUN:     --version \
 // RUN:     -Werror /Zs -- %s 2>&1