[clang] [clang] Fix `gnu::init_priority` attribute handling for reserved values (PR #121577)

[Erich Keane via cfe-commits]

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@@ -3591,15 +3591,20 @@ static void handleInitPriorityAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
     return;
   }
 
+  if (prioritynum < 0 || prioritynum > 65535) {
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erichkeane wrote:

checking `<0` is  silly, it is an unsigned argument.

https://github.com/llvm/llvm-project/pull/121577