[PATCH] D71539: [SCEV] Look through trivial PHIs.

Thu Sep 30 04:27:59 PDT 2021

uabelho added a comment.

Another case that also starts crashing with this patch, and it crashes also after the fix in 0b4a4cc72d81a <https://reviews.llvm.org/rG0b4a4cc72d81a522230a7270abdfa804aa49d89b>:

  opt -passes='loop-mssa(licm,loop-instsimplify,indvars),loop(indvars,simple-loop-unswitch<nontrivial>,loop-unroll-full)' -o /dev/null bbi-60925.ll

I've really tried to reduce the command line  but can't seem to manage.
It crashes with:

  opt: ../include/llvm/Support/Casting.h:104: static bool llvm::isa_impl_cl<llvm::Instruction, const llvm::Value *>::doit(const From *) [To = llvm::Instruction, From = const llvm::Value *]: Assertion `Val && "isa<> used on a null pointer"' failed.
  PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace.
  Stack dump:
  0.	Program arguments: ../../master-github/llvm/build-all/bin/opt -passes=loop-mssa(licm,loop-instsimplify,indvars),loop(indvars,simple-loop-unswitch<nontrivial>,loop-unroll-full) -o /dev/null bbi-60925.ll
   #0 0x0000000002b60f03 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (../../master-github/llvm/build-all/bin/opt+0x2b60f03)
   #1 0x0000000002b5eb7e llvm::sys::RunSignalHandlers() (../../master-github/llvm/build-all/bin/opt+0x2b5eb7e)
   #2 0x0000000002b61286 SignalHandler(int) Signals.cpp:0:0
   #3 0x00007f634fe4b630 __restore_rt sigaction.c:0:0
   #4 0x00007f634d57e387 raise (/lib64/libc.so.6+0x36387)
   #5 0x00007f634d57fa78 abort (/lib64/libc.so.6+0x37a78)
   #6 0x00007f634d5771a6 __assert_fail_base (/lib64/libc.so.6+0x2f1a6)
   #7 0x00007f634d577252 (/lib64/libc.so.6+0x2f252)
   #8 0x0000000001bee8f5 llvm::ScalarEvolution::computeLoopDisposition(llvm::SCEV const*, llvm::Loop const*) (../../master-github/llvm/build-all/bin/opt+0x1bee8f5)
   #9 0x0000000001bed6b1 llvm::ScalarEvolution::getLoopDisposition(llvm::SCEV const*, llvm::Loop const*) (../../master-github/llvm/build-all/bin/opt+0x1bed6b1)
  #10 0x0000000001bb9b46 llvm::ScalarEvolution::isLoopInvariant(llvm::SCEV const*, llvm::Loop const*) (../../master-github/llvm/build-all/bin/opt+0x1bb9b46)
  #11 0x0000000002c31126 llvm::rewriteLoopExitValues(llvm::Loop*, llvm::LoopInfo*, llvm::TargetLibraryInfo*, llvm::ScalarEvolution*, llvm::TargetTransformInfo const*, llvm::SCEVExpander&, llvm::DominatorTree*, llvm::ReplaceExitVal, llvm::SmallVector<llvm::WeakTrackingVH, 16u>&) (../../master-github/llvm/build-all/bin/opt+0x2c31126)
  #12 0x0000000002893599 (anonymous namespace)::IndVarSimplify::run(llvm::Loop*) IndVarSimplify.cpp:0:0
  #13 0x0000000002891aec llvm::IndVarSimplifyPass::run(llvm::Loop&, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>&, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&) (../../master-github/llvm/build-all/bin/opt+0x2891aec)
  #14 0x0000000002e52c2d llvm::detail::PassModel<llvm::Loop, llvm::IndVarSimplifyPass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>::run(llvm::Loop&, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>&, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&) crtstuff.c:0:0
  #15 0x000000000339168f llvm::Optional<llvm::PreservedAnalyses> llvm::PassManager<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>::runSinglePass<llvm::Loop, std::unique_ptr<llvm::detail::PassConcept<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>, std::default_delete<llvm::detail::PassConcept<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&> > > >(llvm::Loop&, std::unique_ptr<llvm::detail::PassConcept<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>, std::default_delete<llvm::detail::PassConcept<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&> > >&, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>&, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&, llvm::PassInstrumentation&) (../../master-github/llvm/build-all/bin/opt+0x339168f)
  #16 0x0000000003391373 llvm::PassManager<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>::runWithoutLoopNestPasses(llvm::Loop&, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>&, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&) (../../master-github/llvm/build-all/bin/opt+0x3391373)
  #17 0x0000000003390a38 llvm::PassManager<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>::run(llvm::Loop&, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>&, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&) (../../master-github/llvm/build-all/bin/opt+0x3390a38)
  #18 0x0000000002e2a2ad llvm::detail::PassModel<llvm::Loop, llvm::PassManager<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>::run(llvm::Loop&, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>&, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&) crtstuff.c:0:0
  #19 0x0000000003392898 llvm::FunctionToLoopPassAdaptor::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (../../master-github/llvm/build-all/bin/opt+0x3392898)
  #20 0x0000000002e5224d llvm::detail::PassModel<llvm::Function, llvm::FunctionToLoopPassAdaptor, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function> >::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) crtstuff.c:0:0
  #21 0x0000000002311915 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function> >::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (../../master-github/llvm/build-all/bin/opt+0x2311915)
  #22 0x0000000000ae8c6d 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>&) crtstuff.c:0:0
  #23 0x0000000002315c96 llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (../../master-github/llvm/build-all/bin/opt+0x2315c96)
  #24 0x00000000007a4b2d llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) crtstuff.c:0:0
  #25 0x0000000002310a58 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (../../master-github/llvm/build-all/bin/opt+0x2310a58)
  #26 0x000000000079c36c llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::StringRef>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool) (../../master-github/llvm/build-all/bin/opt+0x79c36c)
  #27 0x00000000007af756 main (../../master-github/llvm/build-all/bin/opt+0x7af756)
  #28 0x00007f634d56a555 __libc_start_main (/lib64/libc.so.6+0x22555)
  #29 0x00000000007977ac _start (../../master-github/llvm/build-all/bin/opt+0x7977ac)
  Abort

F19328741: bbi-60925.ll <https://reviews.llvm.org/F19328741>

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71539/new/

https://reviews.llvm.org/D71539