[clang] [llvm] [Clang][LLVM][AArch64]Add new feature SSVE-BitPerm (PR #121947)

[via llvm-commits]

================
@@ -34,7 +34,13 @@ rax1 z0.d, z0.d, z0.d
 .arch_extension sve2-bitperm
 .arch_extension nosve2-bitperm
 bgrp z21.s, z10.s, z21.s
-// CHECK: error: instruction requires: sve2-bitperm
+// CHECK: error: instruction requires: sve-bitperm
+// CHECK-NEXT: bgrp z21.s, z10.s, z21.s
+
+.arch_extension sve2-bitperm
+.arch_extension nosve2
+bgrp z21.s, z10.s, z21.s
+// CHECK: error: instruction requires: sve2
----------------
Lukacma wrote:

```suggestion
// CHECK: error: instruction requires: sve2 or ssve-bitperm
```
This message is incomplete

https://github.com/llvm/llvm-project/pull/121947