$cat mutant.c typedef long double a __attribute__((vector_size (16))); a add (a one, a two) { return one + two; } $clang-18 -mgeneral-regs-only -c mutant.c fatal error: error in backend: Cannot select: 0x55560eb9b320: i64 = build_pair 0x55560eb9b6a0, undef:i32 0x55560eb9b6a0: i32,ch = CopyFromReg 0x55560eb9b8d0:1, Register:i32 %14 0x55560eb9b7f0: i32 = Register %14 0x55560eb9e720: i32 = undef In function: add PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script. Stack dump: 0. Program arguments: clang-18 -mgeneral-regs-only -c mutant.c 1. <eof> parser at end of file 2. Code generation 3. Running pass 'Function Pass Manager' on module 'mutant.c'. 4. Running pass 'X86 DAG->DAG Instruction Selection' on function '@add' #0 0x00007fd33ceb2266 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xd2b266) #1 0x00007fd33ceb0170 llvm::sys::RunSignalHandlers() (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xd29170) #2 0x00007fd33ceb18c4 llvm::sys::CleanupOnSignal(unsigned long) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xd2a8c4) #3 0x00007fd33cdff9ae (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xc789ae) #4 0x00007fd33cdff96b (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xc7896b) #5 0x00007fd33ceaca67 llvm::sys::Process::Exit(int, bool) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xd25a67) #6 0x000055560d5e6c23 (/usr/lib/llvm-18/bin/clang+0x13c23) #7 0x00007fd33ce0dc4f llvm::report_fatal_error(llvm::Twine const&, bool) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xc86c4f) #8 0x00007fd33d704100 llvm::SelectionDAGISel::isOrEquivalentToAdd(llvm::SDNode const*) const (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0x157d100) #9 0x00007fd33d7035e8 llvm::SelectionDAGISel::SelectCodeCommon(llvm::SDNode*, unsigned char const*, unsigned int) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0x157c5e8) #10 0x00007fd33fa9a455 (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0x3913455) #11 0x00007fd33d6fb1ec llvm::SelectionDAGISel::DoInstructionSelection() (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0x15741ec) #12 0x00007fd33d6fa8e1 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0x15738e1) #13 0x00007fd33d6f9b71 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0x1572b71) #14 0x00007fd33d6f7cf6 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0x1570cf6) #15 0x00007fd33fa9052f (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0x390952f) #16 0x00007fd33d266552 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0x10df552) #17 0x00007fd33cff80df llvm::FPPassManager::runOnFunction(llvm::Function&) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xe710df) #18 0x00007fd33cffddc3 llvm::FPPassManager::runOnModule(llvm::Module&) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xe76dc3) #19 0x00007fd33cff87d4 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xe717d4) #20 0x00007fd34569509f clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1ade09f) #21 0x00007fd345a2b5fe (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x1e745fe) #22 0x00007fd344647866 clang::ParseAST(clang::Sema&, bool, bool) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0xa90866) #23 0x00007fd34649f645 clang::FrontendAction::Execute() (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x28e8645) #24 0x00007fd34641dcc4 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x2866cc4) #25 0x00007fd34651a1c0 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x29631c0) #26 0x000055560d5e6837 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/usr/lib/llvm-18/bin/clang+0x13837) #27 0x000055560d5e3905 (/usr/lib/llvm-18/bin/clang+0x10905) #28 0x00007fd3460b5909 (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x24fe909) #29 0x00007fd33cdff94c llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/usr/lib/llvm-18/bin/../lib/libLLVM-18.so.1+0xc7894c) #30 0x00007fd3460b52ae clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x24fe2ae) #31 0x00007fd34607d0f1 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x24c60f1) #32 0x00007fd34607d33e clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x24c633e) #33 0x00007fd34609939c clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/usr/lib/llvm-18/bin/../lib/libclang-cpp.so.18+0x24e239c) #34 0x000055560d5e325c clang_main(int, char**, llvm::ToolContext const&) (/usr/lib/llvm-18/bin/clang+0x1025c) #35 0x000055560d5f0f32 main (/usr/lib/llvm-18/bin/clang+0x1df32) #36 0x00007fd33b396c87 __libc_start_main /build/glibc-CVJwZb/glibc-2.27/csu/../csu/libc-start.c:344:0 #37 0x000055560d5e01ea _start (/usr/lib/llvm-18/bin/clang+0xd1ea) clang-18: error: clang frontend command failed with exit code 70 (use -v to see invocation) Ubuntu clang version 18.0.0 (++20231018091808+48a53509e851-1~exp1~20231018091910.1571) Target: x86_64-pc-linux-gnu Thread model: posix InstalledDir: /usr/bin clang-18: note: diagnostic msg: ******************** PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT: Preprocessed source(s) and associated run script(s) are located at: clang-18: note: diagnostic msg: /tmp/mutant-fe7d4a.c clang-18: note: diagnostic msg: /tmp/mutant-fe7d4a.sh clang-18: note: diagnostic msg: ********************