[clang] [clang][sema][FMV] Forbid multi-versioning arm_streaming functions. (PR #81268)

[Sander de Smalen via cfe-commits]

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@@ -454,3 +454,34 @@ void unimplemented_spill_fill_za(void (*share_zt0_only)(void) __arm_inout("zt0")
   // expected-note at +1 {{add '__arm_preserves("za")' to the callee if it preserves ZA}}
   share_zt0_only();
 }
+
+// expected-cpp-error at +2 {{streaming function cannot be multi-versioned}}
+// expected-error at +1 {{streaming function cannot be multi-versioned}}
+__attribute__((target_version("sme2")))
+ // expected-cpp-note at +2 {{previous declaration is here}}
+ // expected-note at +1 {{previous declaration is here}}
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sdesmalen-arm wrote:

nit: I guess these are notes corresponding to the errors on line 465 and 466 right? If so, could you move them to those lines? (and reference it with a negative line offset)

https://github.com/llvm/llvm-project/pull/81268