[PATCH] D101264: [IR] Optimize mayBeDerefined for known linkages. NFC

[Johannes Doerfert via Phabricator via llvm-commits]

jdoerfert added a comment.

Doesn't this change `internal/appending/private dso_local` with "semantic interposition" enabled? TBH, it might just be that those do not make sense (though we seem not to assert on them).
I can see the value of avoiding the roundtrip through isInterposable but the argument by @dblaikie that we should not duplicate stuff is valid too. Though, we already duplicate some stuff.
Maybe, as a compromise to "clean it up", we make a compile time constant array of linkage information

  struct LinkageInformation {
    llvm::Optional<bool> MayBeDerefinedReturn;
    ...
  };
  LinakageInformation LIs[LinkageTypes::__LAST] = {
    LinkageInformation{llvm::None, ...}, // ExternalLinkage
    ...
    LinkageInformation{true, ...}, // WeakODRLinkage
  };
  
  bool mayBeDerefined() const {
    if (LIs[getLinkage()].MayBeDerefinedReturn) return *LIs[getLinkage()].MayBeDerefinedReturn;
    return isInterposable();
  }


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  https://reviews.llvm.org/D101264/new/

https://reviews.llvm.org/D101264