diff options
Diffstat (limited to 'llvm/lib/Analysis/CGSCCPassManager.cpp')
| -rw-r--r-- | llvm/lib/Analysis/CGSCCPassManager.cpp | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/CGSCCPassManager.cpp b/llvm/lib/Analysis/CGSCCPassManager.cpp index 74b5d79..cb6d139 100644 --- a/llvm/lib/Analysis/CGSCCPassManager.cpp +++ b/llvm/lib/Analysis/CGSCCPassManager.cpp @@ -619,6 +619,14 @@ LazyCallGraph::SCC &llvm::updateCGAndAnalysisManagerForFunctionPass( AM.invalidate(*C, PA); } auto NewSCCIndex = RC->find(*C) - RC->begin(); + // If we have actually moved an SCC to be topologically "below" the current + // one due to merging, we will need to revisit the current SCC after + // visiting those moved SCCs. + // + // It is critical that we *do not* revisit the current SCC unless we + // actually move SCCs in the process of merging because otherwise we may + // form a cycle where an SCC is split apart, merged, split, merged and so + // on infinitely. if (InitialSCCIndex < NewSCCIndex) { // Put our current SCC back onto the worklist as we'll visit other SCCs // that are now definitively ordered prior to the current one in the |