[llvm] ThinLTO: Add flag to print uselistorder in bitcode writer pass (PR #133230)

[Matt Arsenault via llvm-commits]

================
@@ -487,9 +488,9 @@ void splitAndWriteThinLTOBitcode(
   // be used in the backends, and use that in the minimized bitcode
   // produced for the full link.
   ModuleHash ModHash = {{0}};
-  W.writeModule(M, /*ShouldPreserveUseListOrder=*/false, &Index,
+  W.writeModule(M, ShouldPreserveUseListOrder, &Index,
                 /*GenerateHash=*/true, &ModHash);
-  W.writeModule(*MergedM, /*ShouldPreserveUseListOrder=*/false, &MergedMIndex);
+  W.writeModule(*MergedM, ShouldPreserveUseListOrder, &MergedMIndex);
----------------
arsenm wrote:

I don't know how to test all these paths. Most of these use are because the bitcode serialization is mixed in with transformations, and llvm-reduce really only wants pure bitcode serialization (e.g. why is AARGetter needed?). There should be a Transforms-free serialization path available, and llvm-reduce really shouldn't depend on the pass manager

https://github.com/llvm/llvm-project/pull/133230