Index: contrib/llvm-project/clang/include/clang/Driver/Options.td
===================================================================
--- contrib/llvm-project/clang/include/clang/Driver/Options.td	(revision 360257)
+++ contrib/llvm-project/clang/include/clang/Driver/Options.td	(working copy)
@@ -819,7 +819,8 @@
   Group<f_clang_Group>;
 def : Flag<["-"], "frecord-gcc-switches">, Alias<frecord_command_line>;
 def : Flag<["-"], "fno-record-gcc-switches">, Alias<fno_record_command_line>;
-def fcommon : Flag<["-"], "fcommon">, Group<f_Group>;
+def fcommon : Flag<["-"], "fcommon">, Group<f_Group>,
+  Flags<[CoreOption, CC1Option]>, HelpText<"Place uninitialized global variables in a common block">;
 def fcompile_resource_EQ : Joined<["-"], "fcompile-resource=">, Group<f_Group>;
 def fcomplete_member_pointers : Flag<["-"], "fcomplete-member-pointers">, Group<f_clang_Group>,
    Flags<[CoreOption, CC1Option]>,
Index: contrib/llvm-project/clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- contrib/llvm-project/clang/lib/Driver/ToolChains/Clang.cpp	(revision 360257)
+++ contrib/llvm-project/clang/lib/Driver/ToolChains/Clang.cpp	(working copy)
@@ -4989,10 +4989,8 @@
     CmdArgs.push_back("-Qn");
 
   // -fcommon is the default unless compiling kernel code or the target says so
-  bool NoCommonDefault = KernelOrKext || isNoCommonDefault(RawTriple);
-  if (!Args.hasFlag(options::OPT_fcommon, options::OPT_fno_common,
-                    !NoCommonDefault))
-    CmdArgs.push_back("-fno-common");
+  if (Args.hasFlag(options::OPT_fcommon, options::OPT_fno_common, false))
+    CmdArgs.push_back("-fcommon");
 
   // -fsigned-bitfields is default, and clang doesn't yet support
   // -funsigned-bitfields.
Index: contrib/llvm-project/clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- contrib/llvm-project/clang/lib/Frontend/CompilerInvocation.cpp	(revision 360257)
+++ contrib/llvm-project/clang/lib/Frontend/CompilerInvocation.cpp	(working copy)
@@ -770,7 +770,7 @@
   Opts.DwarfDebugFlags = Args.getLastArgValue(OPT_dwarf_debug_flags);
   Opts.RecordCommandLine = Args.getLastArgValue(OPT_record_command_line);
   Opts.MergeAllConstants = Args.hasArg(OPT_fmerge_all_constants);
-  Opts.NoCommon = Args.hasArg(OPT_fno_common);
+  Opts.NoCommon = !Args.hasArg(OPT_fcommon);
   Opts.NoImplicitFloat = Args.hasArg(OPT_no_implicit_float);
   Opts.OptimizeSize = getOptimizationLevelSize(Args);
   Opts.SimplifyLibCalls = !(Args.hasArg(OPT_fno_builtin) ||