diff --git a/clang/lib/Driver/ToolChains/Arch/AArch64.cpp b/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
--- a/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
@@ -498,6 +498,11 @@
     Features.insert(std::next(Features.begin() + ArchFeatPos),
                     {"+hbc", "+mops"});
 
+  // Default features for Armv8.9-a/Armv9.4-a or later.
+  if (V8Version >= 9 || V9Version >= 4)
+    Features.insert(std::next(Features.begin() + ArchFeatPos),
+                    {"+specres2", "+cssc", "+rasv2"});
+
   if (Arg *A = Args.getLastArg(options::OPT_mno_unaligned_access,
                                options::OPT_munaligned_access)) {
     if (A->getOption().matches(options::OPT_mno_unaligned_access))
diff --git a/clang/test/Driver/aarch64-cssc.c b/clang/test/Driver/aarch64-cssc.c
--- a/clang/test/Driver/aarch64-cssc.c
+++ b/clang/test/Driver/aarch64-cssc.c
@@ -1,12 +1,13 @@
 // Test that target feature cssc is implemented and available correctly
+// FEAT_CSSC is a required part of v8.9a/v9.4a and optional from v8.7a/v9.3a onwards.
 // RUN: %clang -### -target aarch64-none-none-eabi                         %s 2>&1 | FileCheck %s --check-prefix=ABSENT_CSSC
-// RUN: %clang -### -target aarch64-none-none-eabi -march=armv8.8-a+cssc   %s 2>&1 | FileCheck %s
-// RUN: %clang -### -target aarch64-none-none-eabi -march=armv8.9-a        %s 2>&1 | FileCheck %s --check-prefix=ABSENT_CSSC
-// RUN: %clang -### -target aarch64-none-none-eabi -march=armv8.8-a+cssc   %s 2>&1 | FileCheck %s
+// RUN: %clang -### -target aarch64-none-none-eabi -march=armv8.7-a+cssc   %s 2>&1 | FileCheck %s
+// RUN: %clang -### -target aarch64-none-none-eabi -march=armv8.9-a        %s 2>&1 | FileCheck %s
+// RUN: %clang -### -target aarch64-none-none-eabi -march=armv8.9-a+cssc   %s 2>&1 | FileCheck %s
 // RUN: %clang -### -target aarch64-none-none-eabi -march=armv8.9-a+nocssc %s 2>&1 | FileCheck %s --check-prefix=NO_CSSC
-// RUN: %clang -### -target aarch64-none-none-eabi -march=armv9.3-a+cssc   %s 2>&1 | FileCheck %s
-// RUN: %clang -### -target aarch64-none-none-eabi -march=armv9.4-a        %s 2>&1 | FileCheck %s --check-prefix=ABSENT_CSSC
-// RUN: %clang -### -target aarch64-none-none-eabi -march=armv9.3-a+cssc   %s 2>&1 | FileCheck %s
+// RUN: %clang -### -target aarch64-none-none-eabi -march=armv9.2-a+cssc   %s 2>&1 | FileCheck %s
+// RUN: %clang -### -target aarch64-none-none-eabi -march=armv9.4-a        %s 2>&1 | FileCheck %s
+// RUN: %clang -### -target aarch64-none-none-eabi -march=armv9.4-a+cssc   %s 2>&1 | FileCheck %s
 // RUN: %clang -### -target aarch64-none-none-eabi -march=armv9.4-a+nocssc %s 2>&1 | FileCheck %s --check-prefix=NO_CSSC
 
 // CHECK: "-target-feature" "+cssc"