Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -533,3 +533,12 @@
     ${CLANG_BINARY_DIR}/share/clang/cmake/ClangConfig.cmake
     COPYONLY)
 endif ()
+
+option(ENABLE_CLANG_OPENMP "Enable OpenMP support." ON)
+if (ENABLE_CLANG_OPENMP)
+  set(CLANG_ENABLE_OPENMP "1")
+  add_definitions(-DENABLE_CLANG_OPENMP)
+else()
+  set(CLANG_ENABLE_OPENMP "0")
+endif()
+
Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp
+++ lib/Driver/Tools.cpp
@@ -2592,6 +2592,12 @@
   Result.append(UID.begin(), UID.end());
 }
 
+enum LibOpenMP {
+  LibUnknown,
+  LibGOMP,
+  LibIOMP5
+};
+
 void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                          const InputInfo &Output,
                          const InputInfoList &Inputs,
@@ -3794,8 +3800,23 @@
   Args.AddLastArg(CmdArgs, options::OPT_fno_elide_type);
 
   // Forward flags for OpenMP
-  if (Args.hasArg(options::OPT_fopenmp_EQ) ||
-      Args.hasArg(options::OPT_fopenmp)) {
+  LibOpenMP UsedOpenMPLib = LibUnknown;
+  if (const Arg *A = Args.getLastArg(options::OPT_fopenmp_EQ)) {
+    UsedOpenMPLib = llvm::StringSwitch<LibOpenMP>(A->getValue())
+        .Case("libgomp",  LibGOMP)
+        .Case("libiomp5", LibIOMP5)
+        .Default(LibUnknown);
+    if (UsedOpenMPLib == LibUnknown)
+      getToolChain().getDriver().Diag(diag::err_drv_unsupported_option_argument)
+        << A->getOption().getName() << A->getValue();
+  } else if (Args.hasArg(options::OPT_fopenmp)) {
+#ifdef ENABLE_CLANG_OPENMP
+    UsedOpenMPLib = LibIOMP5;
+#else
+    UsedOpenMPLib = LibGOMP;
+#endif // ENABLE_CLANG_OPENMP
+  }
+  if (UsedOpenMPLib == LibIOMP5) {
     CmdArgs.push_back("-fopenmp");
   }
 
@@ -6215,12 +6236,6 @@
   Args.AddLastArg(CmdArgs, options::OPT_Mach);
 }
 
-enum LibOpenMP {
-  LibUnknown,
-  LibGOMP,
-  LibIOMP5
-};
-
 void darwin::Link::ConstructJob(Compilation &C, const JobAction &JA,
                                 const InputInfo &Output,
                                 const InputInfoList &Inputs,
@@ -6288,7 +6303,11 @@
       getToolChain().getDriver().Diag(diag::err_drv_unsupported_option_argument)
         << A->getOption().getName() << A->getValue();
   } else if (Args.hasArg(options::OPT_fopenmp)) {
+#ifdef ENABLE_CLANG_OPENMP
     UsedOpenMPLib = LibIOMP5;
+#else
+    UsedOpenMPLib = LibGOMP;
+#endif // ENABLE_CLANG_OPENMP
   }
   switch (UsedOpenMPLib) {
   case LibGOMP:
@@ -8013,7 +8032,11 @@
           D.Diag(diag::err_drv_unsupported_option_argument)
               << A->getOption().getName() << A->getValue();
       } else if (Args.hasArg(options::OPT_fopenmp)) {
+#ifdef ENABLE_CLANG_OPENMP
         UsedOpenMPLib = LibIOMP5;
+#else
+        UsedOpenMPLib = LibGOMP;
+#endif // ENABLE_CLANG_OPENMP
       }
       switch (UsedOpenMPLib) {
       case LibGOMP:
Index: test/OpenMP/linking.c
===================================================================
--- test/OpenMP/linking.c
+++ test/OpenMP/linking.c
@@ -1,5 +1,6 @@
 // Test the that the driver produces reasonable linker invocations with
 // -fopenmp or -fopenmp|libgomp.
+// REQUIRES: openmp
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     -fopenmp -target i386-unknown-linux \
Index: test/OpenMP/linking_no_openmp.c
===================================================================
--- test/OpenMP/linking_no_openmp.c
+++ test/OpenMP/linking_no_openmp.c
@@ -0,0 +1,70 @@
+// Test the that the driver produces reasonable linker invocations with
+// -fopenmp or -fopenmp|libgomp.
+// REQUIRES: no_openmp
+//
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     -fopenmp -target i386-unknown-linux \
+// RUN:   | FileCheck --check-prefix=CHECK-LD-32 %s
+// CHECK-LD-32: "{{.*}}ld{{(.exe)?}}"
+// CHECK-LD-32: "-lgomp" "-lrt" "-lgcc"
+// CHECK-LD-32: "-lpthread" "-lc"
+//
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     -fopenmp -target x86_64-unknown-linux \
+// RUN:   | FileCheck --check-prefix=CHECK-LD-64 %s
+// CHECK-LD-64: "{{.*}}ld{{(.exe)?}}"
+// CHECK-LD-64: "-lgomp" "-lrt" "-lgcc"
+// CHECK-LD-64: "-lpthread" "-lc"
+//
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     -fopenmp=libgomp -target i386-unknown-linux \
+// RUN:   | FileCheck --check-prefix=CHECK-GOMP-LD-32 %s
+// CHECK-GOMP-LD-32: "{{.*}}ld{{(.exe)?}}"
+// CHECK-GOMP-LD-32: "-lgomp" "-lrt" "-lgcc"
+// CHECK-GOMP-LD-32: "-lpthread" "-lc"
+//
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     -fopenmp=libgomp -target x86_64-unknown-linux \
+// RUN:   | FileCheck --check-prefix=CHECK-GOMP-LD-64 %s
+// CHECK-GOMP-LD-64: "{{.*}}ld{{(.exe)?}}"
+// CHECK-GOMP-LD-64: "-lgomp" "-lrt" "-lgcc"
+// CHECK-GOMP-LD-64: "-lpthread" "-lc"
+//
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     -fopenmp -target i386-unknown-linux \
+// RUN:   | FileCheck --check-prefix=CHECK-IOMP5-LD-32 %s
+// CHECK-IOMP5-LD-32: "{{.*}}ld{{(.exe)?}}"
+// CHECK-IOMP5-LD-32: "-lgomp" "-lrt" "-lgcc"
+// CHECK-IOMP5-LD-32: "-lpthread" "-lc"
+//
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     -fopenmp -target x86_64-unknown-linux \
+// RUN:   | FileCheck --check-prefix=CHECK-IOMP5-LD-64 %s
+// CHECK-IOMP5-LD-64: "{{.*}}ld{{(.exe)?}}"
+// CHECK-IOMP5-LD-64: "-lgomp" "-lrt" "-lgcc"
+// CHECK-IOMP5-LD-64: "-lpthread" "-lc"
+//
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     -fopenmp=lib -target i386-unknown-linux \
+// RUN:   | FileCheck --check-prefix=CHECK-LIB-LD-32 %s
+// CHECK-LIB-LD-32: error: unsupported argument 'lib' to option 'fopenmp='
+//
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     -fopenmp=lib -target x86_64-unknown-linux \
+// RUN:   | FileCheck --check-prefix=CHECK-LIB-LD-64 %s
+// CHECK-LIB-LD-64: error: unsupported argument 'lib' to option 'fopenmp='
+//
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     -fopenmp -fopenmp=libgomp -target i386-unknown-linux \
+// RUN:   | FileCheck --check-prefix=CHECK-LD-OVERRIDE-32 %s
+// CHECK-LD-OVERRIDE-32: "{{.*}}ld{{(.exe)?}}"
+// CHECK-LD-OVERRIDE-32: "-lgomp" "-lrt" "-lgcc"
+// CHECK-LD-OVERRIDE-32: "-lpthread" "-lc"
+//
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     -fopenmp -fopenmp=libgomp -target x86_64-unknown-linux \
+// RUN:   | FileCheck --check-prefix=CHECK-LD-OVERRIDE-64 %s
+// CHECK-LD-OVERRIDE-64: "{{.*}}ld{{(.exe)?}}"
+// CHECK-LD-OVERRIDE-64: "-lgomp" "-lrt" "-lgcc"
+// CHECK-LD-OVERRIDE-64: "-lpthread" "-lc"
+//
Index: test/lit.cfg
===================================================================
--- test/lit.cfg
+++ test/lit.cfg
@@ -210,6 +210,11 @@
 if config.clang_examples:
     config.available_features.add('examples')
 
+if config.clang_openmp:
+    config.available_features.add('openmp')
+else:
+    config.available_features.add('no_openmp')
+
 # Note that when substituting %clang_cc1 also fill in the include directory of
 # the builtin headers. Those are part of even a freestanding environment, but
 # Clang relies on the driver to locate them.
Index: test/lit.site.cfg.in
===================================================================
--- test/lit.site.cfg.in
+++ test/lit.site.cfg.in
@@ -20,6 +20,7 @@
 config.enable_shared = @ENABLE_SHARED@
 config.enable_backtrace = "@ENABLE_BACKTRACES@"
 config.host_arch = "@HOST_ARCH@"
+config.clang_openmp = "@CLANG_ENABLE_OPENMP@"
 
 # Support substitution of the tools and libs dirs with user parameters. This is
 # used when we can't determine the tool dir at configuration time.