[clang] [clang][sema][NFC] Clean up builtin arg checking functions (PR #158615)

[Timm Baeder via cfe-commits]

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@@ -5886,23 +5886,27 @@ bool Sema::BuiltinOSLogFormat(CallExpr *TheCall) {
   return false;
 }
 
-bool Sema::BuiltinConstantArg(CallExpr *TheCall, int ArgNum,
+bool Sema::BuiltinConstantArg(CallExpr *TheCall, unsigned ArgNum,
                               llvm::APSInt &Result) {
   Expr *Arg = TheCall->getArg(ArgNum);
-  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
-  FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
 
-  if (Arg->isTypeDependent() || Arg->isValueDependent()) return false;
+  if (Arg->isTypeDependent() || Arg->isValueDependent())
+    return false;
 
   std::optional<llvm::APSInt> R;
-  if (!(R = Arg->getIntegerConstantExpr(Context)))
+  if (!(R = Arg->getIntegerConstantExpr(Context))) {
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tbaederr wrote:

I definitely prefer this version but the previous one is used a few times in `SemaChecking.cpp`, probably copied around.

https://github.com/llvm/llvm-project/pull/158615