Index: lib/Driver/ToolChains/Gnu.cpp
===================================================================
--- lib/Driver/ToolChains/Gnu.cpp
+++ lib/Driver/ToolChains/Gnu.cpp
@@ -770,6 +770,12 @@
     Args.AddLastArg(CmdArgs, options::OPT_mfpu_EQ);
     break;
   }
+  case llvm::Triple::aarch64:
+  case llvm::Triple::aarch64_be: {
+    Args.AddLastArg(CmdArgs, options::OPT_march_EQ);
+    Args.AddLastArg(CmdArgs, options::OPT_mcpu_EQ);
+    break;
+  }
   case llvm::Triple::mips:
   case llvm::Triple::mipsel:
   case llvm::Triple::mips64:
Index: test/Driver/linux-as.c
===================================================================
--- test/Driver/linux-as.c
+++ test/Driver/linux-as.c
@@ -100,6 +100,33 @@
 // RUN:   | FileCheck -check-prefix=CHECK-ARM-HARDFP %s
 // CHECK-ARM-HARDFP: as{{(.exe)?}}" "-mfloat-abi=hard"
 //
+// RUN: %clang -target aarch64-linux-gnu -mcpu=cortex-a53 -### \
+// RUN:   -no-integrated-as -c %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-ARM64-MCPU %s
+// CHECK-ARM64-MCPU: as{{(.exe)?}}" "-mcpu=cortex-a53"
+//
+// RUN: %clang -target aarch64-linux-gnu -march=armv8-a -### \
+// RUN:   -no-integrated-as -c %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-ARM64-MARCH %s
+// CHECK-ARM64-MARCH: as{{(.exe)?}}" "-march=armv8-a"
+//
+// RUN: %clang -target aarch64-linux-gnu -mcpu=cortex-a53 -march=armv8-a -### \
+// RUN:   -no-integrated-as -c %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-ARM64-ALL %s
+// CHECK-ARM64-ALL: as{{(.exe)?}}" "-march=armv8-a" "-mcpu=cortex-a53"
+//
+// RUN: %clang -target aarch64_be-linux-gnu -mcpu=cortex-a53 -### \
+// RUN:   -no-integrated-as -c %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-ARM64-MCPU %s
+//
+// RUN: %clang -target aarch64_be-linux-gnu -march=armv8-a -### \
+// RUN:   -no-integrated-as -c %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-ARM64-MARCH %s
+//
+// RUN: %clang -target aarch64_be-linux-gnu -mcpu=cortex-a53 -march=armv8-a -### \
+// RUN:   -no-integrated-as -c %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-ARM64-ALL %s
+//
 // RUN: %clang -target ppc-linux -mcpu=invalid-cpu -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-PPC-NO-MCPU %s