Assertion failed: (TmpVec.size() > 1), function buildUnmerge, llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp, line 609 #47532
Description
| Bugzilla Link | 48188 |
| Resolution | FIXED |
| Resolved on | Mar 05, 2021 09:38 |
| Version | 11.0 |
| OS | MacOS X |
| Blocks | #48246 |
| Attachments | LLVM IR to reproduce the crash |
| CC | @Dushistov,@RKSimon,@nikic,@qcolombet |
| Fixed by commit(s) | c35761d 52510d8 |
Extended Description
% ./bin/llc ../build/bugpoint-reduced-simplified.ll -filetype=obj -mcpu=apple-a12 -march=arm64 -O0 Assertion failed: (TmpVec.size() > 1), function buildUnmerge, file /Users/shepmaster/Projects/llvm-project/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp, line 609. PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace. Stack dump: 0. Program arguments: ./bin/llc ../build/bugpoint-reduced-simplified.ll -filetype=obj -mcpu=apple-a12 -march=arm64 -O0 1. Running pass 'Function Pass Manager' on module '../build/bugpoint-reduced-simplified.ll'. 2. Running pass 'Legalizer' on function '@_ZN3std2io5stdio8print_to17h83af8c48359573cfE' 0 llc 0x0000000106c22658 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 76 1 llc 0x0000000106c22b68 PrintStackTraceSignalHandler(void*) + 32 2 llc 0x0000000106c20bd8 llvm::sys::RunSignalHandlers() + 124 3 llc 0x0000000106c24ac4 SignalHandler(int) + 208 4 libsystem_platform.dylib 0x000000018941cc44 _sigtramp + 56 5 libsystem_pthread.dylib 0x00000001893d4c24 pthread_kill + 292 6 libsystem_c.dylib 0x000000018931c864 abort + 104 7 libsystem_c.dylib 0x000000018931bb68 err + 0 8 llc 0x000000010729d1dc llvm::MachineIRBuilder::buildUnmerge(llvm::ArrayRef<llvm::Register>, llvm::SrcOp const&) + 168 9 llc 0x000000010724c894 llvm::LegalizerHelper::extractParts(llvm::Register, llvm::LLT, int, llvm::SmallVectorImpl<llvm::Register>&) + 248 10 llc 0x0000000107244c08 llvm::LegalizerHelper::narrowScalar(llvm::MachineInstr&, unsigned int, llvm::LLT) + 8564 11 llc 0x0000000107241ec0 llvm::LegalizerHelper::legalizeInstrStep(llvm::MachineInstr&) + 492 12 llc 0x000000010722bf48 llvm::Legalizer::legalizeMachineFunction(llvm::MachineFunction&, llvm::LegalizerInfo const&, llvm::ArrayRef<llvm::GISelChangeObserver*>, llvm::LostDebugLocObserver&, llvm::MachineIRBuilder&) + 1104 13 llc 0x000000010722da2c llvm::Legalizer::runOnMachineFunction(llvm::MachineFunction&) + 964 14 llc 0x000000010552ce70 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) + 460 15 llc 0x0000000105d4a29c llvm::FPPassManager::runOnFunction(llvm::Function&) + 548 16 llc 0x0000000105d51a68 llvm::FPPassManager::runOnModule(llvm::Module&) + 116 17 llc 0x0000000105d4ab08 (anonymous namespace)::MPPassManager::runOnModule(llvm::Module&) + 688 18 llc 0x0000000105d4a6a0 llvm::legacy::PassManagerImpl::run(llvm::Module&) + 272 19 llc 0x0000000105d51e84 llvm::legacy::PassManager::run(llvm::Module&) + 36 20 llc 0x0000000104597258 compileModule(char**, llvm::LLVMContext&) + 5304 21 llc 0x0000000104595590 main + 1288 22 libdyld.dylib 0x00000001893f0f54 start + 4 Doing some light debugging, I see that NumParts is 1; this is what triggers the assertion. This is computed from SizeOp0 / NarrowSize when SizeOp0 is 120 and NarrowSize is 64.
The Rust fork is currently at 2e10b7a. git-bisect says that the attached LLVM IR compiles successfully starting at db464a3.
However, I don't believe that the bug is actually fixed, merely hidden. The commit in question performs more transformations to the code and causes SizeOp0 to be 128. When I cherry-picked that commit back to the Rust fork, the problems continue to manifest.