[llvm] [Linker] Do not keep a private member of a non-prevailing comdat group (PR #69143)

[Reid Kleckner via llvm-commits]

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@@ -473,6 +474,9 @@ bool ModuleLinker::run() {
       return true;
     ComdatsChosen[&C] = std::make_pair(SK, From);
 
+    if (From == LinkFrom::Dst)
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rnk wrote:

I think for COFF (not for ELF) in the comdat-refer-to-discarded.ll test case we should get a result of `LinkFrom::Both` here.

https://github.com/llvm/llvm-project/pull/69143