[llvm] [IR] Avoid collecting COMDATs for non-module printing (PR #221460)

[Alexis Engelke via llvm-commits]

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@@ -3243,13 +3235,14 @@ void AssemblyWriter::printModule(const Module *M) {
 
   printTypeIdentities();
 
-  // Output all comdats.
-  if (!Comdats.empty())
+  // Output each used comdat at its first global object.
+  SmallPtrSet<const Comdat *, 8> PrintedComdats;
+  for (const GlobalObject &GO : M->global_objects()) {
+    const Comdat *C = GO.getComdat();
+    if (!C || !PrintedComdats.insert(C).second)
+      continue;
     Out << '\n';
-  for (const Comdat *C : Comdats) {
     printComdat(C);
-    if (C != Comdats.back())
-      Out << '\n';
   }
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aengelke wrote:

Wrap in nested block to free set early.

https://github.com/llvm/llvm-project/pull/221460