diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -1019,6 +1019,13 @@
   auto Open = [&]() { return ::open(P.begin(), OpenFlags, Mode); };
   if ((ResultFD = sys::RetryAfterSignal(-1, Open)) < 0)
     return std::error_code(errno, std::generic_category());
+  if (Access == FA_Read) {
+    struct stat Status;
+    if (stat(P.begin(), &Status) == -1)
+      return std::error_code(errno, std::generic_category());
+    if (S_ISDIR(Status.st_mode))
+      return make_error_code(errc::is_a_directory);
+  }    
 #ifndef O_CLOEXEC
   if (!(Flags & OF_ChildInherit)) {
     int r = fcntl(ResultFD, F_SETFD, FD_CLOEXEC);
diff --git a/llvm/test/tools/llvm-symbolizer/input-file-err.test b/llvm/test/tools/llvm-symbolizer/input-file-err.test
--- a/llvm/test/tools/llvm-symbolizer/input-file-err.test
+++ b/llvm/test/tools/llvm-symbolizer/input-file-err.test
@@ -1,5 +1,3 @@
-Failing on AIX due to D153595. The test expects a different error message from the one given on AIX.
-XFAIL: target={{.*}}-aix{{.*}}
 RUN: not llvm-addr2line -e %p/Inputs/nonexistent 0x12 2>&1 | FileCheck %s --check-prefix=CHECK-NONEXISTENT-A2L -DMSG=%errc_ENOENT
 RUN: not llvm-addr2line -e %p/Inputs/nonexistent 2>&1 | FileCheck %s --check-prefix=CHECK-NONEXISTENT-A2L -DMSG=%errc_ENOENT
 CHECK-NONEXISTENT-A2L: llvm-addr2line{{.*}}: error: '{{.*}}Inputs/nonexistent': [[MSG]]
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) {