diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 661e6f40985622caabe75e108fd29448f32872fe..3b20805c884660357387ab146c3ac7b13f444f53 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -2527,9 +2527,11 @@ static bool DecodeAArch64Mcpu(const Driver &D, StringRef Mcpu, StringRef &CPU,
     Features.push_back("+neon");
   } else {
     unsigned ArchKind = llvm::AArch64::parseCPUArch(CPU);
-    unsigned Extersion = llvm::AArch64::getDefaultExtensions(CPU, ArchKind);
+    if (!llvm::AArch64::getArchFeatures(ArchKind, Features))
+      return false;
 
-    if (!llvm::AArch64::getExtensionFeatures(Extersion, Features))
+    unsigned Extension = llvm::AArch64::getDefaultExtensions(CPU, ArchKind);
+    if (!llvm::AArch64::getExtensionFeatures(Extension, Features))
       return false;
    }
 
diff --git a/test/Driver/aarch64-cpus.c b/test/Driver/aarch64-cpus.c
index 3ba6d94312c2cae6eae536a7a03e898500b0e2f9..88edcc5fc8d82a5b0e770b5f70e86e951201b213 100644
--- a/test/Driver/aarch64-cpus.c
+++ b/test/Driver/aarch64-cpus.c
@@ -157,16 +157,20 @@
 // RUN: %clang -target aarch64 -mcpu=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=VULCAN %s
 // RUN: %clang -target aarch64 -mlittle-endian -mcpu=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=VULCAN %s
 // RUN: %clang -target aarch64_be -mlittle-endian -mcpu=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=VULCAN %s
-// RUN: %clang -target aarch64 -mtune=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=VULCAN %s
-// RUN: %clang -target aarch64 -mlittle-endian -mtune=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=VULCAN %s
-// RUN: %clang -target aarch64_be -mlittle-endian -mtune=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=VULCAN %s
-// VULCAN: "-cc1"{{.*}} "-triple" "aarch64{{.*}}" "-target-cpu" "vulcan"
+// RUN: %clang -target aarch64 -mtune=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=VULCAN-TUNE %s
+// RUN: %clang -target aarch64 -mlittle-endian -mtune=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=VULCAN-TUNE %s
+// RUN: %clang -target aarch64_be -mlittle-endian -mtune=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=VULCAN-TUNE %s
+// VULCAN: "-cc1"{{.*}} "-triple" "aarch64{{.*}}" "-target-cpu" "vulcan" "-target-feature" "+v8.1a"
+// VULCAN-TUNE: "-cc1"{{.*}} "-triple" "aarch64{{.*}}" "-target-cpu" "vulcan"
+// VULCAN-TUNE-NOT: +v8.1a
 
 // RUN: %clang -target arm64 -mcpu=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=ARM64-VULCAN %s
 // RUN: %clang -target arm64 -mlittle-endian -mcpu=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=ARM64-VULCAN %s
-// RUN: %clang -target arm64 -mtune=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=ARM64-VULCAN %s
-// RUN: %clang -target arm64 -mlittle-endian -mtune=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=ARM64-VULCAN %s
-// ARM64-VULCAN: "-cc1"{{.*}} "-triple" "arm64{{.*}}" "-target-cpu" "vulcan"
+// RUN: %clang -target arm64 -mtune=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=ARM64-VULCAN-TUNE %s
+// RUN: %clang -target arm64 -mlittle-endian -mtune=vulcan -### -c %s 2>&1 | FileCheck -check-prefix=ARM64-VULCAN-TUNE %s
+// ARM64-VULCAN: "-cc1"{{.*}} "-triple" "arm64{{.*}}" "-target-cpu" "vulcan" "-target-feature" "+v8.1a"
+// ARM64-VULCAN-TUNE: "-cc1"{{.*}} "-triple" "arm64{{.*}}" "-target-cpu" "vulcan"
+// ARM64-VULCAN-TUNE-NOT: +v8.1a
 
 // RUN: %clang -target aarch64_be -### -c %s 2>&1 | FileCheck -check-prefix=GENERIC-BE %s
 // RUN: %clang -target aarch64 -mbig-endian -### -c %s 2>&1 | FileCheck -check-prefix=GENERIC-BE %s