diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -896,12 +896,7 @@
 bool MachO::HasNativeLLVMSupport() const { return true; }
 
 ToolChain::CXXStdlibType Darwin::GetDefaultCXXStdlibType() const {
-  // Use libstdc++ on old targets (OSX < 10.9 and iOS < 7)
-  if ((isTargetMacOSBased() && isMacosxVersionLT(10, 9)) ||
-      (isTargetIOSBased() && isIPhoneOSVersionLT(7, 0)))
-    return ToolChain::CST_Libstdcxx;
-
-  // On all other targets, use libc++
+  // Always use libc++ by default
   return ToolChain::CST_Libcxx;
 }
 
diff --git a/clang/test/Driver/darwin-iphone-defaults.m b/clang/test/Driver/darwin-iphone-defaults.m
--- a/clang/test/Driver/darwin-iphone-defaults.m
+++ b/clang/test/Driver/darwin-iphone-defaults.m
@@ -1,4 +1,4 @@
-// RUN: %clang -target i386-apple-darwin9 -miphoneos-version-min=3.0 -arch armv7 -stdlib=platform -flto -S -o - %s | FileCheck %s
+// RUN: %clang -target i386-apple-darwin -miphoneos-version-min=5.0 -arch armv7 -stdlib=platform -flto -S -o - %s | FileCheck %s
 
 // CHECK: @f0() [[F0:#[0-9]+]]
 // CHECK: @__f0_block_invoke
diff --git a/clang/test/Driver/darwin-stdlib.cpp b/clang/test/Driver/darwin-stdlib.cpp
--- a/clang/test/Driver/darwin-stdlib.cpp
+++ b/clang/test/Driver/darwin-stdlib.cpp
@@ -1,14 +1,10 @@
-// This test will fail if CLANG_DEFAULT_CXX_STDLIB is set to anything different
-// than the platform default. (see https://llvm.org/bugs/show_bug.cgi?id=30548)
-// XFAIL: default-cxx-stdlib-set
+// This test will fail if CLANG_DEFAULT_CXX_STDLIB is set to libstdc++.
+// XFAIL: default-cxx-stdlib=libstdc++
 
-// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %S/Inputs/darwin_toolchain_tree/bin/ -arch arm64 -miphoneos-version-min=7.0 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-LIBCXX
-// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %S/Inputs/darwin_toolchain_tree/bin/ -mmacosx-version-min=10.8 -Wno-stdlibcxx-not-found %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-LIBSTDCXX
-// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %S/Inputs/darwin_toolchain_tree/bin/ -mmacosx-version-min=10.9 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-LIBCXX
-// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %S/Inputs/darwin_toolchain_tree/bin/ -arch armv7s -miphoneos-version-min=6.1 -Wno-stdlibcxx-not-found %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-LIBSTDCXX
-// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %S/Inputs/darwin_toolchain_tree/bin/ -arch armv7s -miphoneos-version-min=7.0 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-LIBCXX
-// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %S/Inputs/darwin_toolchain_tree/bin/ -arch armv7k %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-LIBCXX
+// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %S/Inputs/darwin_toolchain_tree/bin/ -arch arm64 -miphoneos-version-min=7.0 %s -### 2>&1 | FileCheck %s
+// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %S/Inputs/darwin_toolchain_tree/bin/ -mmacosx-version-min=10.9 %s -### 2>&1 | FileCheck %s
+// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %S/Inputs/darwin_toolchain_tree/bin/ -arch armv7s -miphoneos-version-min=7.0 %s -### 2>&1 | FileCheck %s
+// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %S/Inputs/darwin_toolchain_tree/bin/ -arch armv7k %s -### 2>&1 | FileCheck %s
 
-// CHECK-LIBCXX: "-stdlib=libc++"
-// CHECK-LIBSTDCXX-NOT: -stdlib=libc++
-// CHECK-LIBSTDCXX-NOT: -stdlib=libstdc++
+// CHECK: "-stdlib=libc++"
+// CHECK-NOT: "-stdlib=libstdc++"
diff --git a/clang/test/lit.cfg.py b/clang/test/lit.cfg.py
--- a/clang/test/lit.cfg.py
+++ b/clang/test/lit.cfg.py
@@ -134,7 +134,7 @@
 # Set available features we allow tests to conditionalize on.
 #
 if config.clang_default_cxx_stdlib != '':
-    config.available_features.add('default-cxx-stdlib-set')
+    config.available_features.add('default-cxx-stdlib={}'.format(config.clang_default_cxx_stdlib))
 
 # As of 2011.08, crash-recovery tests still do not pass on FreeBSD.
 if platform.system() not in ['FreeBSD']: