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Description
While debugging loongson-community/discussions#87 I hit this ICE when I attempted to disable SIMD entirely.
Minimized reproducer:
// clang-20 --march=loongarch64 -mno-lsx -S -o - "x.cc"
__attribute__((__vector_size__(16))) long foo = __builtin_lsx_vinsgr2vr_w(foo, 0, 0);; RUN: llc issue131771.ll
target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"
target triple = "loongarch64-unknown-linux-gnu"
define void @__cxx_global_var_init() #0 {
%1 = call <4 x i32> @llvm.loongarch.lsx.vinsgr2vr.w(<4 x i32> zeroinitializer, i32 0, i32 0)
%2 = bitcast <4 x i32> %1 to <2 x i64>
store <2 x i64> %2, ptr null, align 16
ret void
}
; Function Attrs: nounwind memory(none)
declare <4 x i32> @llvm.loongarch.lsx.vinsgr2vr.w(<4 x i32>, i32, i32 immarg) #1
attributes #0 = { "target-cpu"="loongarch64" }
attributes #1 = { nounwind memory(none) }Output:
x.cc:1:75: warning: variable 'foo' is uninitialized when used within its own initialization [-Wuninitialized]
1 | __attribute__((__vector_size__(16))) long foo = __builtin_lsx_vinsgr2vr_w(foo, 0, 0);
| ~~~ ^~~
fatal error: error in backend: Do not know how to split the result of this operator!
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-20 -march=loongarch64 -mno-lsx -S -o - x.cc
1. <eof> parser at end of file
2. Code generation
3. Running pass 'Function Pass Manager' on module 'x.cc'.
4. Running pass 'LoongArch DAG->DAG Pattern Instruction Selection' on function '@__cxx_global_var_init'
#0 0x00007fffe6a258c4 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x7c58c4)
#1 0x00007fffe6a2341c llvm::sys::RunSignalHandlers() (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x7c341c)
#2 0x00007fffe69418f8 (anonymous namespace)::CrashRecoveryContextImpl::HandleCrash(int, unsigned long) CrashRecoveryContext.cpp:0:0
#3 0x00007fffe6941894 (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x6e1894)
#4 0x00007fffe6a1f4f4 llvm::sys::Process::Exit(int, bool) (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x7bf4f4)
#5 0x0000555556811788 LLVMErrorHandler(void*, char const*, bool) cc1_main.cpp:0:0
#6 0x00007fffe695403c llvm::report_fatal_error(llvm::Twine const&, bool) (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x6f403c)
#7 0x00007fffe6953f1c (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x6f3f1c)
#8 0x00007fffe72bd228 (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x105d228)
#9 0x00007fffe729a3d0 llvm::DAGTypeLegalizer::run() (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x103a3d0)
#10 0x00007fffe729f214 llvm::SelectionDAG::LegalizeTypes() (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x103f214)
#11 0x00007fffe73ae430 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x114e430)
#12 0x00007fffe73adc60 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x114dc60)
#13 0x00007fffe73abfc4 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x114bfc4)
#14 0x00007fffe73aa718 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x114a718)
#15 0x00007fffe6ea7ab8 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0xc47ab8)
#16 0x00007fffe6bb58a8 llvm::FPPassManager::runOnFunction(llvm::Function&) (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x9558a8)
#17 0x00007fffe6bbc324 llvm::FPPassManager::runOnModule(llvm::Module&) (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x95c324)
#18 0x00007fffe6bb5fb4 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x955fb4)
#19 0x00007fffefbd1558 clang::emitBackendOutput(clang::CompilerInstance&, clang::CodeGenOptions&, 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>>, clang::BackendConsumer*) (/usr/lib/llvm/20/bin/../lib64/libclang-cpp.so.20.1+0x1ca1558)
#20 0x00007ffff0000990 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/usr/lib/llvm/20/bin/../lib64/libclang-cpp.so.20.1+0x20d0990)
#21 0x00007fffee6a2edc clang::ParseAST(clang::Sema&, bool, bool) (/usr/lib/llvm/20/bin/../lib64/libclang-cpp.so.20.1+0x772edc)
#22 0x00007ffff09cd1dc clang::FrontendAction::Execute() (/usr/lib/llvm/20/bin/../lib64/libclang-cpp.so.20.1+0x2a9d1dc)
#23 0x00007ffff096115c clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/lib/llvm/20/bin/../lib64/libclang-cpp.so.20.1+0x2a3115c)
#24 0x00007ffff0a53618 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/usr/lib/llvm/20/bin/../lib64/libclang-cpp.so.20.1+0x2b23618)
#25 0x0000555556813e04 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/usr/lib/llvm/20/bin/clang-20+0x13e04)
#26 0x000055555680e318 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#27 0x00007ffff05900e4 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#28 0x00007fffe694185c llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/usr/lib/llvm/20/bin/../lib64/libLLVM.so.20.1+0x6e185c)
#29 0x00007ffff05925d0 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/20/bin/../lib64/libclang-cpp.so.20.1+0x26625d0)
#30 0x00007ffff05541b4 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/usr/lib/llvm/20/bin/../lib64/libclang-cpp.so.20.1+0x26241b4)
#31 0x00007ffff05548b4 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/usr/lib/llvm/20/bin/../lib64/libclang-cpp.so.20.1+0x26248b4)
#32 0x00007ffff05685cc clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/usr/lib/llvm/20/bin/../lib64/libclang-cpp.so.20.1+0x26385cc)
#33 0x000055555680f86c clang_main(int, char**, llvm::ToolContext const&) (/usr/lib/llvm/20/bin/clang-20+0xf86c)
#34 0x000055555680c7d8 main (/usr/lib/llvm/20/bin/clang-20+0xc7d8)
#35 0x00007fffe5d9d54c __libc_start_call_main /usr/src/debug/sys-libs/glibc-2.41-r1/glibc-2.41/csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#36 0x00007fffe5d9d630 call_init /usr/src/debug/sys-libs/glibc-2.41-r1/glibc-2.41/csu/../csu/libc-start.c:128:20
#37 0x00007fffe5d9d630 __libc_start_main@@GLIBC_2.36 /usr/src/debug/sys-libs/glibc-2.41-r1/glibc-2.41/csu/../csu/libc-start.c:347:5
#38 0x000055555680c888 _start (/usr/lib/llvm/20/bin/clang-20+0xc888)
clang-20: error: clang frontend command failed with exit code 70 (use -v to see invocation)
clang version 20.1.0
Target: loongarch64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/lib/llvm/20/bin
Configuration file: /etc/clang/20/loongarch64-unknown-linux-gnu-clang.cfg
clang-20: note: diagnostic msg:
********************
PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-20: note: diagnostic msg: /tmp/x-b7247c.cpp
clang-20: note: diagnostic msg: /tmp/x-b7247c.sh
clang-20: note: diagnostic msg:
********************
We shouldn't crash even though the user request might be invalid.