[PATCH] D35918: [GVNHoist] Factor out reachability to search for anticipable instructions quickly

[Jakub Kuderski via Phabricator via llvm-commits]

kuhar added a comment.

In https://reviews.llvm.org/D35918#831066, @hiraditya wrote:

> I tried a simple df walk like this, it crashes the compiler for the test cases llvm/test/Transforms/GVNHoist/infinite-loop-indirect.ll, and llvm/test/Transforms/GVNHoist/infinite-loop-direct.ll:
>
>   auto PrevBB = PDT->getNode(nullptr);
>    for (auto it = df_begin(PrevBB); it != df_end(PrevBB);
>         ++it) {
>    }
>   
>
> These test cases are added in this patch.
>
> Thanks,


I tried running loop like yours in a couple of my unittests (`DominatorTreeTest.cpp`) and it seems to work:

  auto PrevBB = PDT->getNode(nullptr);
  for (auto it = df_begin(PrevBB); it != df_end(PrevBB);
       ++it) {
    auto BB = it->getBlock();
    outs() << (BB ?B B->getName() : "virtual root") << "\n";
  }

Could you prepare a reduced repro for the crash you saw?

Thanks,
Kuba


https://reviews.llvm.org/D35918