<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Issue</th>
<td>
<a href=https://github.com/llvm/llvm-project/issues/55589>55589</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>
clang -O1 (higher than 0) crashes if LLVM is built with -flto
</td>
</tr>
<tr>
<th>Labels</th>
<td>
</td>
</tr>
<tr>
<th>Assignees</th>
<td>
</td>
</tr>
<tr>
<th>Reporter</th>
<td>
somespa
</td>
</tr>
</table>
<pre>
If LLVM is built with -flto in compiling flags, clang -O1(-O2,-O3) crashes on any .c file, even this one:
cat loop.c
#include <stdio.h>
int main(void){for ( int i=0; i<1; i++);}
clang -v -O1 -emit-llvm -c -o foo.bc loop.c
clang version 14.0.3
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/lib/llvm/14/bin
Selected GCC installation: /usr/lib/gcc/x86_64-pc-linux-gnu/11.3.0
Candidate multilib: .;@m64
Selected multilib: .;@m64
(in-process)
"/usr/lib/llvm/14/bin/clang-14" -cc1 -triple x86_64-pc-linux-gnu -emit-llvm-bc -emit-llvm-uselists -disable-free -clear-ast-before-backend -main-file-name loop.c -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=none -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -mllvm -treat-scalable-fixed-error-as-warning -debugger-tuning=gdb -v -fcoverage-compilation-dir=/home/j -resource-dir /usr/lib/llvm/14/bin/../../../../lib/clang/14.0.3 -internal-isystem /usr/lib/llvm/14/bin/../../../../lib/clang/14.0.3/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-pc-linux-gnu/11.3.0/../../../../x86_64-pc-linux-gnu/include -internal-externc-isystem /include -internal-externc-isystem /usr/include -O1 -fdebug-compilation-dir=/home/j -ferror-limit 19 -fgnuc-version=4.2.1 -fcolor-diagnostics -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o foo.bc -x c loop.c
clang -cc1 version 14.0.3 based upon LLVM 14.0.3 default target x86_64-pc-linux-gnu
ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory "/usr/lib/gcc/x86_64-pc-linux-gnu/11.3.0/../../../../x86_64-pc-linux-gnu/include"
ignoring nonexistent directory "/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/lib/llvm/14/bin/../../../../lib/clang/14.0.3/include
/usr/include
End of search list.
clang: /var/tmp/portage/sys-devel/llvm-14.0.3/work/llvm/lib/IR/User.cpp:45: void llvm::User::allocHungoffUses(unsigned int, bool): Assertion `HasHungOffUses && "alloc must have hung off uses"' failed.
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 -v -O1 -emit-llvm -c -o foo.bc loop.c
1. <eof> parser at end of file
2. Optimizer
#0 0x00007fb9f41bfc72 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0xe3cc72)
#1 0x00007fb9f4177f34 llvm::sys::RunSignalHandlers() (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0xdf4f34)
#2 0x00007fb9f4112d58 (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0xd8fd58)
#3 0x00007fb9f2f957a0 (/lib64/libc.so.6+0x3d7a0)
#4 0x00007fb9f2fe12cc (/lib64/libc.so.6+0x892cc)
#5 0x00007fb9f2f95702 gsignal (/lib64/libc.so.6+0x3d702)
#6 0x00007fb9f2f80469 abort (/lib64/libc.so.6+0x28469)
#7 0x00007fb9f2f80395 (/lib64/libc.so.6+0x28395)
#8 0x00007fb9f2f8e962 (/lib64/libc.so.6+0x36962)
#9 0x00007fb9f4358bd9 llvm::User::allocHungoffUses(unsigned int, bool) (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0xfd5bd9)
#10 0x00007fb9f424867f (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0xec567f)
#11 0x00007fb9f707e3a9 (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0x3cfb3a9)
#12 0x00007fb9f4d66945 llvm::PromoteMemToReg(llvm::ArrayRef<llvm::AllocaInst*>, llvm::DominatorTree&, llvm::AssumptionCache*) (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0x19e3945)
#13 0x00007fb9f510a394 llvm::SROAPass::promoteAllocas(llvm::Function&) (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0x1d87394)
#14 0x00007fb9f51320f8 llvm::SROAPass::runImpl(llvm::Function&, llvm::DominatorTree&, llvm::AssumptionCache&) (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0x1daf0f8)
#15 0x00007fb9f6ca30f6 (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0x39200f6)
#16 0x00007fb9f43605b9 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function> >::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0xfdd5b9)
#17 0x00007fb9f5e1ac52 (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0x2a97c52)
#18 0x00007fb9f43639d1 llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0xfe09d1)
#19 0x00007fb9f5e1a692 (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0x2a97692)
#20 0x00007fb9f4347bc9 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0xfc4bc9)
#21 0x00007fb9fcd38b85 (/usr/lib/llvm/14/bin/../lib64/libclang-cpp.so.14+0x269cb85)
#22 0x00007fb9fbd8a3de clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream> >) (/usr/lib/llvm/14/bin/../lib64/libclang-cpp.so.14+0x16ee3de)
#23 0x00007fb9fc0c35d5 (/usr/lib/llvm/14/bin/../lib64/libclang-cpp.so.14+0x1a275d5)
#24 0x00007fb9faf9d12d clang::ParseAST(clang::Sema&, bool, bool) (/usr/lib/llvm/14/bin/../lib64/libclang-cpp.so.14+0x90112d)
#25 0x00007fb9fc760161 clang::FrontendAction::Execute() (/usr/lib/llvm/14/bin/../lib64/libclang-cpp.so.14+0x20c4161)
#26 0x00007fb9fc6f4b7d clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/lib/llvm/14/bin/../lib64/libclang-cpp.so.14+0x2058b7d)
#27 0x00007fb9fc7a9620 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/usr/lib/llvm/14/bin/../lib64/libclang-cpp.so.14+0x210d620)
#28 0x0000562969e507aa cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/usr/lib/llvm/14/bin/clang-14+0x157aa)
#29 0x0000562969e55ee8 (/usr/lib/llvm/14/bin/clang-14+0x1aee8)
#30 0x00007fb9fc4351f5 (/usr/lib/llvm/14/bin/../lib64/libclang-cpp.so.14+0x1d991f5)
#31 0x00007fb9f40fa832 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/usr/lib/llvm/14/bin/../lib64/libLLVM-14.so+0xd77832)
#32 0x00007fb9fc4563ae clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, bool*) const (/usr/lib/llvm/14/bin/../lib64/libclang-cpp.so.14+0x1dba3ae)
#33 0x00007fb9fc4209c9 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&) const (/usr/lib/llvm/14/bin/../lib64/libclang-cpp.so.14+0x1d849c9)
#34 0x00007fb9fc420de1 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*> >&) const (/usr/lib/llvm/14/bin/../lib64/libclang-cpp.so.14+0x1d84de1)
#35 0x00007fb9fc427eb1 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*> >&) (/usr/lib/llvm/14/bin/../lib64/libclang-cpp.so.14+0x1d8beb1)
#36 0x0000562969e4c34a main (/usr/lib/llvm/14/bin/clang-14+0x1134a)
#37 0x00007fb9f2f811ea (/lib64/libc.so.6+0x291ea)
#38 0x00007fb9f2f8129c __libc_start_main (/lib64/libc.so.6+0x2929c)
#39 0x0000562969e4d2b1 _start (/usr/lib/llvm/14/bin/clang-14+0x122b1)
clang-14: error: clang frontend command failed with exit code 134 (use -v to see invocation)
clang version 14.0.3
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/lib/llvm/14/bin
clang-14: note: diagnostic msg:
********************
PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-14: note: diagnostic msg: /tmp/loop-b54cc5.c
clang-14: note: diagnostic msg: /tmp/loop-b54cc5.sh
clang-14: note: diagnostic msg:
********************
/tmp/loop-b54cc5.c = https://dpaste.com/4SA8J8L2A
/tmp/loop-b54cc5.sh = https://dpaste.com/FMBQLYRXJ
</pre>
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