Index: clang/CMakeLists.txt
===================================================================
--- clang/CMakeLists.txt
+++ clang/CMakeLists.txt
@@ -238,6 +238,10 @@
 
 set(CLANG_SYSTEMZ_DEFAULT_ARCH "z10" CACHE STRING "SystemZ Default Arch")
 
+if (NOT (CLANG_AARCH64_DEFAULT_CPU))
+  set(CLANG_AARCH64_DEFAULT_CPU "generic" CACHE STRING "AArch64 Default CPU")
+endif()
+
 set(CLANG_VENDOR ${PACKAGE_VENDOR} CACHE STRING
   "Vendor-specific text for showing with version information.")
 
Index: clang/include/clang/Config/config.h.cmake
===================================================================
--- clang/include/clang/Config/config.h.cmake
+++ clang/include/clang/Config/config.h.cmake
@@ -32,6 +32,9 @@
 /* Default architecture for SystemZ. */
 #define CLANG_SYSTEMZ_DEFAULT_ARCH "${CLANG_SYSTEMZ_DEFAULT_ARCH}"
 
+/* Default CPU for AArch64. */
+#define CLANG_AARCH64_DEFAULT_CPU "${CLANG_AARCH64_DEFAULT_CPU}"
+
 /* Multilib basename for libdir. */
 #define CLANG_INSTALL_LIBDIR_BASENAME "${CLANG_INSTALL_LIBDIR_BASENAME}"
 
Index: clang/lib/Driver/ToolChains/Arch/AArch64.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Arch/AArch64.cpp
+++ clang/lib/Driver/ToolChains/Arch/AArch64.cpp
@@ -8,6 +8,7 @@
 
 #include "AArch64.h"
 #include "../CommonArgs.h"
+#include "clang/Config/config.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/Options.h"
@@ -63,7 +64,7 @@
     return Triple.getArch() == llvm::Triple::aarch64_32 ? "apple-s4"
                                                         : "apple-a7";
 
-  return "generic";
+  return CLANG_AARCH64_DEFAULT_CPU;
 }
 
 // Decode AArch64 features from string like +[no]featureA+[no]featureB+...