[clang] [AArch64][SME] Warn when using a streaming builtin from a non-streaming function (PR #74064)

[Sander de Smalen via cfe-commits]

================
@@ -3168,11 +3168,70 @@ static void checkArmStreamingBuiltin(Sema &S, CallExpr *TheCall,
         << TheCall->getSourceRange() << "streaming compatible";
     return;
   }
+
+  if (FnType == ArmNonStreaming && BuiltinType == ArmStreaming) {
+    S.Diag(TheCall->getBeginLoc(), diag::warn_attribute_arm_sm_incompat_builtin)
+        << TheCall->getSourceRange() << "non-streaming";
+  }
+}
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sdesmalen-arm wrote:

I think this functionality is big enough to warrant it own PR, such that we have:
* One PR for testing the compatibility of streaming-mode for both SVE and SME.
* One PR for testing that the calling function of a ZA-using builtin has ZA state.

https://github.com/llvm/llvm-project/pull/74064