Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td	(revision 168426)
+++ include/clang/Driver/Options.td	(working copy)
@@ -590,7 +590,8 @@
 def fobjc_sender_dependent_dispatch : Flag<["-"], "fobjc-sender-dependent-dispatch">, Group<f_Group>;
 def fobjc : Flag<["-"], "fobjc">, Group<f_Group>;
 def fomit_frame_pointer : Flag<["-"], "fomit-frame-pointer">, Group<f_Group>;
-def fopenmp : Flag<["-"], "fopenmp">, Group<f_Group>;
+def fopenmp : Flag<["-"], "fopenmp">, Group<f_Group>, Flags<[CC1Option]>;
+def fno_openmp : Flag<["-"], "fno-openmp">, Group<f_Group>, Flags<[CC1Option]>;
 def fno_optimize_sibling_calls : Flag<["-"], "fno-optimize-sibling-calls">, Group<f_Group>;
 def foptimize_sibling_calls : Flag<["-"], "foptimize-sibling-calls">, Group<f_Group>;
 def force__cpusubtype__ALL : Flag<["-"], "force_cpusubtype_ALL">;
Index: include/clang/Basic/LangOptions.def
===================================================================
--- include/clang/Basic/LangOptions.def	(revision 168426)
+++ include/clang/Basic/LangOptions.def	(working copy)
@@ -168,6 +168,10 @@
 
 BENIGN_LANGOPT(RetainCommentsFromSystemHeaders, 1, 0, "retain documentation comments from system headers in the AST")
 
+/// OpenMP
+LANGOPT(OpenMP, 1, 0, "Enables OpenMP support.")
+LANGOPT(NoOpenMP, 1, 0, "Disables OpenMP support.")
+
 /// Runtime sanitizers.
 #define SANITIZER(NAME, ID) \
 BENIGN_LANGOPT(Sanitize##ID, 1, 0, NAME " sanitizer")
Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp	(revision 168426)
+++ lib/Driver/Tools.cpp	(working copy)
@@ -2504,6 +2504,16 @@
 
   Args.AddLastArg(CmdArgs, options::OPT_pthread);
 
+  // When both -fopenmp and -fno-openmp options are present,
+  // later one wins.
+  if (Arg *A = Args.getLastArg(options::OPT_fopenmp,
+                               options::OPT_fno_openmp)) {
+    if (A->getOption().matches(options::OPT_fopenmp)) {
+      CmdArgs.push_back("-fopenmp");
+    } else {
+      CmdArgs.push_back("-fno-openmp");
+    }
+  }
 
   // -stack-protector=0 is default.
   unsigned StackProtectorLevel = 0;
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp	(revision 168426)
+++ lib/Frontend/CompilerInvocation.cpp	(working copy)
@@ -1239,6 +1239,11 @@
   Opts.ApplePragmaPack = Args.hasArg(OPT_fapple_pragma_pack);
   Opts.CurrentModule = Args.getLastArgValue(OPT_fmodule_name);
 
+  // If -fopenmp enablement fails, then check, if -fno-openmp is need to be 
+  // enabled.
+  if (!(Opts.OpenMP = Args.hasFlag(OPT_fopenmp, OPT_fno_openmp, false)))
+    Opts.NoOpenMP = Args.hasFlag(OPT_fno_openmp, OPT_fopenmp, false);
+
   // Record whether the __DEPRECATED define was requested.
   Opts.Deprecated = Args.hasFlag(OPT_fdeprecated_macro,
                                  OPT_fno_deprecated_macro,
Index: test/Driver/openmp-options.c
===================================================================
--- test/Driver/openmp-options.c	(revision 0)
+++ test/Driver/openmp-options.c	(revision 0)
@@ -0,0 +1,14 @@
+// Neither -fopenmp nor -fno-openmp is passed.
+// RUN: %clang -### -S -o %t %s  2>&1 | not grep -w -- -fopenmp && not grep -w -- -fno-openmp
+
+// Only -fopenmp is passed.
+// RUN: %clang -### -S -o %t %s -fopenmp  2>&1 | grep -w -- -fopenmp && not grep -w -- -fno-openmp
+
+// Both -fopenmp and -fno-openmp are passed. But, -fopenmp wins as it appears after -fno-openmp.
+// RUN: %clang -### -S -o %t %s -fno-openmp -fopenmp  2>&1 | grep -w -- -fopenmp && not grep -w -- -fno-openmp
+
+// Only -fno-openmp is passed.
+// RUN: %clang -### -S -o %t %s -fno-openmp  2>&1 | grep -w -- -fno-openmp && not grep -w -- -fopenmp
+
+// Both -fopenmp and -fno-openmp are passed. But, -fno-openmp wins as it appears after -fopenmp.
+// RUN: %clang -### -S -o %t %s -fopenmp -fno-openmp  2>&1 | grep -w -- -fno-openmp && not grep -w -- -fopenmp