[clang] [X86_64] fix SSE type error in vaarg. (PR #86377)

[Longsheng Mou via cfe-commits]

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@@ -21,3 +21,18 @@ empty empty_record_test(int z, ...) {
   __builtin_va_start(list, z);
   return __builtin_va_arg(list, empty);
 }
+
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CoTinker wrote:

done

https://github.com/llvm/llvm-project/pull/86377