diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
+++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -212,6 +212,8 @@
   # -fPIC does not enable the large code model for GCC on AIX but does for XL.
   if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
     append("-mcmodel=large" CMAKE_CXX_FLAGS CMAKE_C_FLAGS)
+    append("-Wl, bglink=large"
+        CMAKE_EXE_LINKER_FLAGS CMAKE_MODULE_LINKER_FLAGS CMAKE_SHARED_LINKER_FLAGS)
   elseif(CMAKE_CXX_COMPILER_ID MATCHES "XL")
     # XL generates a small number of relocations not of the large model, -bbigtoc is needed.
     append("-Wl,-bbigtoc"
diff --git a/llvm/lib/Support/CommandLine.cpp b/llvm/lib/Support/CommandLine.cpp
--- a/llvm/lib/Support/CommandLine.cpp
+++ b/llvm/lib/Support/CommandLine.cpp
@@ -1306,6 +1306,11 @@
     }
     const llvm::vfs::Status &FileStatus = Res.get();
 
+    if (FileStatus.isDirectory()) {
+      return createStringError(std::make_error_code(std::errc::is_a_directory),
+                               Twine("cannot not open file '") + FName +
+                                   "': Is a directory");
+    }
     auto IsEquivalent =
         [FileStatus, this](const ResponseFileRecord &RFile) -> ErrorOr<bool> {
       ErrorOr<llvm::vfs::Status> RHS = FS->status(RFile.File);
diff --git a/llvm/unittests/Support/CommandLineTest.cpp b/llvm/unittests/Support/CommandLineTest.cpp
--- a/llvm/unittests/Support/CommandLineTest.cpp
+++ b/llvm/unittests/Support/CommandLineTest.cpp
@@ -1060,7 +1060,6 @@
   ASSERT_STREQ(Argv[0], "clang");
   ASSERT_STREQ(Argv[1], AFileExp.c_str());
 
-#if !defined(_AIX) && !defined(__MVS__)
   std::string ADirExp = std::string("@") + std::string(ADir.path());
   Argv = {"clang", ADirExp.c_str()};
   Res = cl::ExpandResponseFiles(Saver, cl::TokenizeGNUCommandLine, Argv);
@@ -1068,7 +1067,6 @@
   ASSERT_EQ(2U, Argv.size());
   ASSERT_STREQ(Argv[0], "clang");
   ASSERT_STREQ(Argv[1], ADirExp.c_str());
-#endif
 }
 
 TEST(CommandLineTest, SetDefaultValue) {