opt -loop-reroll crashes with Assertion `!LoopControlIV && "Found two loop control only IV"' failed.

[mikaelholmen]

llvm commit: 4a42ce2
Reproduce with:
opt -loop-reroll -o /dev/null bbi-64678.ll

Result:
opt: ../lib/Transforms/Scalar/LoopRerollPass.cpp:606: void (anonymous namespace)::LoopReroll::collectPossibleIVs(llvm::Loop , (anonymous namespace)::LoopReroll::SmallInstructionVector &): Assertion `!LoopControlIV && "Found two loop control only IV"' failed.
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace.
Stack dump:
0. Program arguments: build-all/bin/opt -loop-reroll -o /dev/null bbi-64678.ll
#0 0x0000000002c70bf3 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (build-all/bin/opt+0x2c70bf3)
#1 0x0000000002c6e86e llvm::sys::RunSignalHandlers() (build-all/bin/opt+0x2c6e86e)
#2 0x0000000002c70f76 SignalHandler(int) Signals.cpp:0:0
#3 0x00007fad63977630 __restore_rt sigaction.c:0:0
#4 0x00007fad610aa387 raise (/lib64/libc.so.6+0x36387)
#5 0x00007fad610aba78 abort (/lib64/libc.so.6+0x37a78)
#6 0x00007fad610a31a6 __assert_fail_base (/lib64/libc.so.6+0x2f1a6)
#7 0x00007fad610a3252 (/lib64/libc.so.6+0x2f252)
#8 0x0000000002a1387e (anonymous namespace)::LoopReroll::runOnLoop(llvm::Loop) LoopRerollPass.cpp:0:0
#9 0x0000000002a0fa8b llvm::LoopRerollPass::run(llvm::Loop&, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>&, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&) (build-all/bin/opt+0x2a0fa8b)
#10 0x0000000002f891cd llvm::detail::PassModel<llvm::Loop, llvm::LoopRerollPass, 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
#11 0x000000000346894f llvm::Optionalllvm::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&) (build-all/bin/opt+0x346894f)
#12 0x0000000003468573 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&) (build-all/bin/opt+0x3468573)
#13 0x0000000003467c38 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&) (build-all/bin/opt+0x3467c38)
#14 0x0000000002f6c2ed 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
#15 0x0000000003469c4b llvm::FunctionToLoopPassAdaptor::run(llvm::Function&, llvm::AnalysisManagerllvm::Function&) (build-all/bin/opt+0x3469c4b)
#16 0x0000000002f8805d llvm::detail::PassModel<llvm::Function, llvm::FunctionToLoopPassAdaptor, llvm::PreservedAnalyses, llvm::AnalysisManagerllvm::Function >::run(llvm::Function&, llvm::AnalysisManagerllvm::Function&) crtstuff.c:0:0
#17 0x00000000023e7805 llvm::PassManager<llvm::Function, llvm::AnalysisManagerllvm::Function >::run(llvm::Function&, llvm::AnalysisManagerllvm::Function&) (build-all/bin/opt+0x23e7805)
#18 0x0000000000b07a2d llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManagerllvm::Function >, llvm::PreservedAnalyses, llvm::AnalysisManagerllvm::Function >::run(llvm::Function&, llvm::AnalysisManagerllvm::Function&) crtstuff.c:0:0
#19 0x00000000023ebc2a llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManagerllvm::Module&) (build-all/bin/opt+0x23ebc2a)
#20 0x00000000007a429d llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::PreservedAnalyses, llvm::AnalysisManagerllvm::Module >::run(llvm::Module&, llvm::AnalysisManagerllvm::Module&) crtstuff.c:0:0
#21 0x00000000023e6948 llvm::PassManager<llvm::Module, llvm::AnalysisManagerllvm::Module >::run(llvm::Module&, llvm::AnalysisManagerllvm::Module&) (build-all/bin/opt+0x23e6948)
#22 0x000000000079c032 llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRefllvm::StringRef, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool) (build-all/bin/opt+0x79c032)
#23 0x00000000007aed04 main (build-all/bin/opt+0x7aed04)
#24 0x00007fad61096555 __libc_start_main (/lib64/libc.so.6+0x22555)
#25 0x000000000079747c _start (build-all/bin/opt+0x79747c)
Abort

bbi-64678.ll.gz

This is old, it starts crashing with old builds from sep 2020. Before that the -loop-reroll flag isn't recognized.

[caojoshua]

candidate https://reviews.llvm.org/D141109

[xgupta]

Fixed on the trunk - https://godbolt.org/z/j5Yda4GeY.