[llvm] [AArch64][SME2] Add ZT0 attributes to SMEAttrs (PR #77607)

[Sander de Smalen via llvm-commits]

================
@@ -2160,6 +2160,21 @@ void Verifier::verifyFunctionAttrs(FunctionType *FT, AttributeList Attrs,
            V);
   }
 
+  if (Attrs.hasFnAttr("aarch64_sme_new_zt0") ||
+      Attrs.hasFnAttr("aarch64_sme_in_zt0") ||
+      Attrs.hasFnAttr("aarch64_sme_inout_zt0") ||
+      Attrs.hasFnAttr("aarch64_sme_out_zt0") ||
+      Attrs.hasFnAttr("aarch64_sme_preserved_zt0")) {
+    Check((Attrs.hasFnAttr("aarch64_sme_new_zt0") ^
+           Attrs.hasFnAttr("aarch64_sme_in_zt0") ^
+           Attrs.hasFnAttr("aarch64_sme_inout_zt0") ^
+           Attrs.hasFnAttr("aarch64_sme_out_zt0") ^
+           Attrs.hasFnAttr("aarch64_sme_preserved_zt0")),
----------------
sdesmalen-arm wrote:

What about:

```
Check((Attrs.hasFnAttr("aarch64_sme_new_zt0") + 
       Attrs.hasFnAttr("aarch64_sme_in_zt0") + 
       Attrs.hasFnAttr("aarch64_sme_inout_zt0") + 
       Attrs.hasFnAttr("aarch64_sme_out_zt0") + 
       Attrs.hasFnAttr("aarch64_sme_preserved_zt0")) <= 1,
      "<message>", V);
```
?

https://github.com/llvm/llvm-project/pull/77607