[clang] [clang][FMV] Do not omit explicit default target_version attribute. (PR #96628)

[Tomas Matheson via cfe-commits]

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@@ -11465,6 +11465,10 @@ static bool CheckMultiVersionFirstFunction(Sema &S, FunctionDecl *FD) {
   // otherwise it is treated as a normal function.
   if (TA && !TA->isDefaultVersion())
     return false;
+  // The target_version attribute only causes Multiversioning if this
+  // declaration is NOT the default version.
+  if (TVA && TVA->isDefaultVersion())
+    return false;
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tmatheson-arm wrote:

Is it allowed to have both `target` and `target_version` on the same function? If so, can these early returns interfere with each other?

https://github.com/llvm/llvm-project/pull/96628