[PATCH] D123720: [VPlan] Replace use of needsVectorIV with VPlan user check.

[Alexander Kornienko via Phabricator via llvm-commits]

alexfh added a comment.

The last recommit of this patch (8b48223447311af8b3022697dd58858e1ce6975f <https://reviews.llvm.org/rG8b48223447311af8b3022697dd58858e1ce6975f> "Recommit ""[VPlan] Remove uneeded needsVectorIV check.""") causes the compiler to crash on some of our code. A reduced test case:

  $ cat q.cc
  int a[2];
  int b;
  bool c() {
    bool d;
    for (int e; e; e--) {
      d = !d;
      b += d ?: a[e];
    }
    return b;
  }
  $ ./clang -cc1 -triple x86_64--linux-gnu -emit-obj -O2 -vectorize-loops q.cc
  Stack dump:
  0.      Program arguments: ./clang -cc1 -triple x86_64--linux-gnu -emit-obj -O2 -vectorize-loops q.cc
  1.      <eof> parser at end of file
  2.      Optimizer
   #0 0x000055cb5104bfa8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (./clang+0x6e4bfa8)
   #1 0x000055cb5104c3c5 SignalHandler(int) (./clang+0x6e4c3c5)
   #2 0x00007f464c15b750 __restore_rt (/usr/grte/v5/lib64/libpthread.so.0+0x15750)
   #3 0x000055cb4d2f15fc llvm::VPlanTransforms::optimizeInductions(llvm::VPlan&, llvm::ScalarEvolution&) (./clang+0x30f15fc)
   #4 0x000055cb4d2eae74 llvm::LoopVectorizationPlanner::buildVPlanWithVPRecipes(llvm::VFRange&, llvm::SmallPtrSetImpl<llvm::Instruction*>&, llvm::MapVector<llvm::Instruction*, llvm::Instruction*, llvm::DenseMap<llvm::Instruction*, unsigned int, llvm::DenseMapInfo<llvm::Instruction*, void>, llvm::detail::DenseMapPair<llvm::Instruction*, unsigned int> >, std::__u::vector<std::__u::pair<llvm::Instruction*, llvm::Instruction*>, std::__u::allocator<std::__u::pair<llvm::Instruction*, llvm::Instruction*> > > > const&) (./clang+0x30eae74)
   #5 0x000055cb4d2e903b llvm::LoopVectorizationPlanner::buildVPlansWithVPRecipes(llvm::ElementCount, llvm::ElementCount) (./clang+0x30e903b)
   #6 0x000055cb4e865734 llvm::LoopVectorizePass::processLoop(llvm::Loop*) (.cold) (./clang+0x4665734)
   #7 0x000055cb4d143dcf llvm::LoopVectorizePass::runImpl(llvm::Function&, llvm::ScalarEvolution&, llvm::LoopInfo&, llvm::TargetTransformInfo&, llvm::DominatorTree&, llvm::BlockFrequencyInfo&, llvm::TargetLibraryInfo*, llvm::DemandedBits&, llvm::AAResults&, llvm::AssumptionCache&, std::__u::function<llvm::LoopAccessInfo const& (llvm::Loop&)>&, llvm::OptimizationRemarkEmitter&, llvm::ProfileSummaryInfo*) (./clang+0x2f43dcf)
   #8 0x000055cb4d143b7d llvm::LoopVectorizePass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (./clang+0x2f43b7d)
   #9 0x000055cb4d143832 llvm::detail::PassModel<llvm::Function, llvm::LoopVectorizePass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function> >::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (./clang+0x2f43832)
  #10 0x000055cb4db331fd llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function> >::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (./clang+0x39331fd)
  #11 0x000055cb4db32db2 llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function> >, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function> >::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (./clang+0x3932db2)
  #12 0x000055cb4d95fd16 llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (./clang+0x375fd16)
  #13 0x000055cb4d3cca92 llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (./clang+0x31cca92)
  #14 0x000055cb4d1fdbe4 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (./clang+0x2ffdbe4)
  #15 0x000055cb4d233efd (anonymous namespace)::EmitAssemblyHelper::RunOptimizationPipeline(clang::BackendAction, std::__u::unique_ptr<llvm::raw_pwrite_stream, std::__u::default_delete<llvm::raw_pwrite_stream> >&, std::__u::unique_ptr<llvm::ToolOutputFile, std::__u::default_delete<llvm::ToolOutputFile> >&) (./clang+0x3033efd)
  #16 0x000055cb4d22cee5 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, std::__u::unique_ptr<llvm::raw_pwrite_stream, std::__u::default_delete<llvm::raw_pwrite_stream> >) (./clang+0x302cee5)
  #17 0x000055cb4dd2e253 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (./clang+0x3b2e253)
  #18 0x000055cb4d226af4 clang::ParseAST(clang::Sema&, bool, bool) (./clang+0x3026af4)
  #19 0x000055cb4d308654 clang::FrontendAction::Execute() (./clang+0x3108654)
  #20 0x000055cb4d308472 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (./clang+0x3108472)
  #21 0x000055cb4d3082e5 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (./clang+0x31082e5)
  #22 0x000055cb4dcf3fca cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (./clang+0x3af3fca)
  #23 0x000055cb4d3cab81 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) (./clang+0x31cab81)
  #24 0x000055cb4dbdddf2 main (./clang+0x39dddf2)
  #25 0x00007f464bfe98d3 __libc_start_main (/usr/grte/v5/lib64/libc.so.6+0x628d3)
  #26 0x000055cb4d3ca9fa _start (./clang+0x31ca9fa)
  Segmentation fault

Do you see how to fix this quickly? Otherwise, please revert the commit while you're working on a fix. Thanks!


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D123720/new/

https://reviews.llvm.org/D123720