[clang] Fix/interp init list unnamed bitfields (PR #87799)

[Timm Baeder via cfe-commits]

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@@ -884,8 +884,36 @@ bool ByteCodeExprGen<Emitter>::visitInitList(ArrayRef<const Expr *> Inits,
     if (!this->emitDupPtr(E))
       return false;
 
+    // guard relatively expensive base check behind an almost-always-false
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tbaederr wrote:

The comment sounds like this is just a performance improvement. Is that so?

https://github.com/llvm/llvm-project/pull/87799