clang crashes on valid code at -O{2,3} on x86_64-linux-gnu: Assertion `(VF.isScalar() || Def->isLiveIn() || hasVectorValue(Def, Part) || !vputils::onlyFirstLaneUsed(Def) || (hasScalarValue(Def, VPIteration(Part, 0)) && Data.PerPartScalars[Def][Part].size() == 1)) && "Trying to access a single scalar per part but has multiple scalars " "per part."' failed

[zhendongsu]

Compiler Explorer: https://godbolt.org/z/8nPY4WWMe

[527] % clangtk -v
clang version 20.0.0git (https://github.com/llvm/llvm-project.git d84411f686e7755c620c93d77c5f6adba88d28a5)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /local/suz-local/software/local/clang-trunk/bin
Build config: +assertions
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/10
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/11
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/9
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/11
Candidate multilib: .;@m64
Selected multilib: .;@m64
[528] % 
[528] % clangtk -O2 -c small.c
clangtk: /local/suz-local/software/clangbuild/llvm-project/llvm/lib/Transforms/Vectorize/VPlan.cpp:260: llvm::Value* llvm::VPTransformState::get(llvm::VPValue*, unsigned int, bool): Assertion `(VF.isScalar() || Def->isLiveIn() || hasVectorValue(Def, Part) || !vputils::onlyFirstLaneUsed(Def) || (hasScalarValue(Def, VPIteration(Part, 0)) && Data.PerPartScalars[Def][Part].size() == 1)) && "Trying to access a single scalar per part but has multiple scalars " "per part."' 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: clangtk -I/usr/local/include -I/local/suz-local/software/local/include -O2 -c small.c
1.	<eof> parser at end of file
2.	Optimizer
3.	Running pass "function<eager-inv>(float2int,lower-constant-intrinsics,loop(loop-rotate<header-duplication;no-prepare-for-lto>,loop-deletion),loop-distribute,inject-tli-mappings,loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>,infer-alignment,loop-load-elim,instcombine<max-iterations=1;no-verify-fixpoint>,simplifycfg<bonus-inst-threshold=1;forward-switch-cond;switch-range-to-icmp;switch-to-lookup;no-keep-loops;hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,slp-vectorizer,vector-combine,instcombine<max-iterations=1;no-verify-fixpoint>,loop-unroll<O2>,transform-warning,sroa<preserve-cfg>,infer-alignment,instcombine<max-iterations=1;no-verify-fixpoint>,loop-mssa(licm<allowspeculation>),alignment-from-assumptions,loop-sink,instsimplify,div-rem-pairs,tailcallelim,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;speculate-unpredictables>)" on module "small.c"
4.	Running pass "loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>" on function "main"
 #0 0x0000561008fa6c6f llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x438ac6f)
 #1 0x0000561008fa47bc llvm::sys::CleanupOnSignal(unsigned long) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x43887bc)
 #2 0x0000561008eed878 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007f814dc82420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
 #4 0x00007f814d6b900b raise /build/glibc-LcI20x/glibc-2.31/signal/../sysdeps/unix/sysv/linux/raise.c:51:1
 #5 0x00007f814d698859 abort /build/glibc-LcI20x/glibc-2.31/stdlib/abort.c:81:7
 #6 0x00007f814d698729 get_sysdep_segment_value /build/glibc-LcI20x/glibc-2.31/intl/loadmsgcat.c:509:8
 #7 0x00007f814d698729 _nl_load_domain /build/glibc-LcI20x/glibc-2.31/intl/loadmsgcat.c:970:34
 #8 0x00007f814d6a9fd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)
 #9 0x000056100aa6cb2e llvm::VPTransformState::get(llvm::VPValue*, unsigned int, bool) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5e50b2e)
#10 0x000056100aa9835f llvm::VPBlendRecipe::execute(llvm::VPTransformState&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5e7c35f)
#11 0x000056100aa64167 llvm::VPBasicBlock::executeRecipes(llvm::VPTransformState*, llvm::BasicBlock*) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5e48167)
#12 0x000056100aa65a1e llvm::VPBasicBlock::execute(llvm::VPTransformState*) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5e49a1e)
#13 0x000056100aa6786f llvm::VPRegionBlock::execute(llvm::VPTransformState*) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5e4b86f)
#14 0x000056100aa6cfc6 llvm::VPlan::execute(llvm::VPTransformState*) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5e50fc6)
#15 0x000056100a940f80 llvm::LoopVectorizationPlanner::executePlan(llvm::ElementCount, unsigned int, llvm::VPlan&, llvm::InnerLoopVectorizer&, llvm::DominatorTree*, bool, llvm::DenseMap<llvm::SCEV const*, llvm::Value*, llvm::DenseMapInfo<llvm::SCEV const*, void>, llvm::detail::DenseMapPair<llvm::SCEV const*, llvm::Value*>> const*) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5d24f80)
#16 0x000056100a959a70 llvm::LoopVectorizePass::processLoop(llvm::Loop*) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5d3da70)
#17 0x000056100a95bae1 llvm::LoopVectorizePass::runImpl(llvm::Function&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5d3fae1)
#18 0x000056100a95c153 llvm::LoopVectorizePass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5d40153)
#19 0x000056100a4caa36 llvm::detail::PassModel<llvm::Function, llvm::LoopVectorizePass, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x58aea36)
#20 0x0000561008936431 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x3d1a431)
#21 0x000056100646bb06 llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x184fb06)
#22 0x0000561008934d9d llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x3d18d9d)
#23 0x000056100646a6e6 llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x184e6e6)
#24 0x00005610089347d1 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x3d187d1)
#25 0x000056100925fc83 (anonymous namespace)::EmitAssemblyHelper::RunOptimizationPipeline(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>&, std::unique_ptr<llvm::ToolOutputFile, std::default_delete<llvm::ToolOutputFile>>&, clang::BackendConsumer*) BackendUtil.cpp:0:0
#26 0x00005610092631dd 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>>, clang::BackendConsumer*) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x46471dd)
#27 0x000056100993f74c clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x4d2374c)
#28 0x000056100b7d588c clang::ParseAST(clang::Sema&, bool, bool) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x6bb988c)
#29 0x000056100993fb68 clang::CodeGenAction::ExecuteAction() (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x4d23b68)
#30 0x0000561009c07089 clang::FrontendAction::Execute() (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x4feb089)
#31 0x0000561009b835ce clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x4f675ce)
#32 0x0000561009cf3946 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x50d7946)
#33 0x0000561006033365 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x1417365)
#34 0x000056100602ae7a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#35 0x0000561009985acd 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
#36 0x0000561008eedd80 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x42d1d80)
#37 0x00005610099860ef clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#38 0x0000561009949d64 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x4d2dd64)
#39 0x000056100994ae7d clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x4d2ee7d)
#40 0x0000561009952f65 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x4d36f65)
#41 0x000056100603013b clang_main(int, char**, llvm::ToolContext const&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x141413b)
#42 0x0000561005f1c4fb main (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x13004fb)
#43 0x00007f814d69a083 __libc_start_main /build/glibc-LcI20x/glibc-2.31/csu/../csu/libc-start.c:342:3
#44 0x000056100602a90e _start (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x140e90e)
clangtk: error: clang frontend command failed with exit code 134 (use -v to see invocation)
clang version 20.0.0git (https://github.com/llvm/llvm-project.git d84411f686e7755c620c93d77c5f6adba88d28a5)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /local/suz-local/software/local/clang-trunk/bin
Build config: +assertions
clangtk: note: diagnostic msg: 
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clangtk: note: diagnostic msg: /tmp/small-fd3ead.c
clangtk: note: diagnostic msg: /tmp/small-fd3ead.sh
clangtk: note: diagnostic msg: 

********************
[529] % 
[529] % cat small.c
short a, j;
int c, d, f, k, l, e, g, h, m, n, o, p, q, r;
volatile int i;
extern int s();
short t(int u) { return a ? u / a : 0; }
int main() {
  while (e) {
    int b = 0;
    if (h) {
      for (; r; r++)
        l = a ? o / a : 0;
    af:
      while (s())
        ;
      while (i)
        p = b;
      while (q)
        s();
      for (; p; p++) {
        j = t(m < 1);
        d = c >> j;
        if (k)
          b = 1;
      }
    }
    if (f)
      goto af;
    while (g)
      ;
    while (1)
      if (n)
        break;
  }
  return 0;
}

[dyung]

One of our internal tests also hit this assertion failure with a repro that I reduced to the following:

#define a(b) safe_##b
long c, d;
int i[];
long *e;
int f;
int a(mod_func_uint64_t_u_u)(long g) { return g == 0 ? c : c % g; }
int h() {
  for (; f; f++) {
    *i = safe_mod_func_uint64_t_u_u(*e);
    d = 7;
  }
}

Compiling with optimizations and -mavx2 shows the crash:

$ ~/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang -c -O2 -mavx2 repro.c
repro.c:12:1: warning: non-void function does not return a value [-Wreturn-type]
   12 | }
      | ^
repro.c:3:5: warning: tentative array definition assumed to have one element [-Wtentative-definition-array]
    3 | int i[];
      |     ^
clang: /home/dyung/src/upstream/llvm_clean_git/llvm/lib/Transforms/Vectorize/VPlan.cpp:260: llvm::Value* llvm::VPTransformState::get(llvm::VPValue*, unsigned int, bool): Assertion `(VF.isScalar() || Def->isLiveIn() || hasVectorValue(Def, Part) || !vputils::onlyFirstLaneUsed(Def) || (hasScalarValue(Def, VPIteration(Part, 0)) && Data.PerPartScalars[Def][Part].size() == 1)) && "Trying to access a single scalar per part but has multiple scalars " "per part."' 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: /home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang -c -O2 -mavx2 repro.c
1.      <eof> parser at end of file
2.      Optimizer
3.      Running pass "function<eager-inv>(float2int,lower-constant-intrinsics,loop(loop-rotate<header-duplication;no-prepare-for-lto>,loop-deletion),loop-distribute,inject-tli-mappings,loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>,infer-alignment,loop-load-elim,instcombine<max-iterations=1;no-verify-fixpoint>,simplifycfg<bonus-inst-threshold=1;forward-switch-cond;switch-range-to-icmp;switch-to-lookup;no-keep-loops;hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;sink-common-insts;speculate-blocks;simplify-con
d-branch;no-speculate-unpredictables>,slp-vectorizer,vector-combine,instcombine<max-iterations=1;no-verify-fixpoint>,loop-unroll<O2>,transform-warning,sroa<preserve-cfg>,infer-alignment,instcombine<max-iterations=1;no-verify-fixpoint>,loop-mssa(licm<allowspeculation>),alignment-from-assumptions,loop-sink,instsimplify,div-rem-pairs,tailcallelim,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-
blocks;simplify-cond-branch;speculate-unpredictables>)" on module "repro.c"
4.      Running pass "loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>" on function "h"
 #0 0x000055cb582c2def llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x2335def)
 #1 0x000055cb582c093c llvm::sys::CleanupOnSignal(unsigned long) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x233393c)
 #2 0x000055cb58212ce8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007f00f41e7420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
 #4 0x00007f00f3cb400b raise /build/glibc-LcI20x/glibc-2.31/signal/../sysdeps/unix/sysv/linux/raise.c:51:1
 #5 0x00007f00f3c93859 abort /build/glibc-LcI20x/glibc-2.31/stdlib/abort.c:81:7
 #6 0x00007f00f3c93729 get_sysdep_segment_value /build/glibc-LcI20x/glibc-2.31/intl/loadmsgcat.c:509:8
 #7 0x00007f00f3c93729 _nl_load_domain /build/glibc-LcI20x/glibc-2.31/intl/loadmsgcat.c:970:34
 #8 0x00007f00f3ca4fd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)
 #9 0x000055cb59e3a5ce llvm::VPTransformState::get(llvm::VPValue*, unsigned int, bool) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x3ead5ce)
#10 0x000055cb59e65dff llvm::VPBlendRecipe::execute(llvm::VPTransformState&) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x3ed8dff)
#11 0x000055cb59e31c07 llvm::VPBasicBlock::executeRecipes(llvm::VPTransformState*, llvm::BasicBlock*) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x3ea4c07)
#12 0x000055cb59e334be llvm::VPBasicBlock::execute(llvm::VPTransformState*) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x3ea64be)
#13 0x000055cb59e3530f llvm::VPRegionBlock::execute(llvm::VPTransformState*) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x3ea830f)
#14 0x000055cb59e3aa66 llvm::VPlan::execute(llvm::VPTransformState*) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x3eada66)
#15 0x000055cb59d16980 llvm::LoopVectorizationPlanner::executePlan(llvm::ElementCount, unsigned int, llvm::VPlan&, llvm::InnerLoopVectorizer&, llvm::DominatorTree*, bool, llvm::DenseMap<llvm::SCEV const*, llvm::Value*, llvm::DenseMapInfo<llvm::SCEV const*, void>, llvm::detail::DenseMapPair<llvm::SCEV const*, llvm::Value*>> const*) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x3d89980)
#16 0x000055cb59d2f470 llvm::LoopVectorizePass::processLoop(llvm::Loop*) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x3da2470)
#17 0x000055cb59d314e1 llvm::LoopVectorizePass::runImpl(llvm::Function&) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x3da44e1)
#18 0x000055cb59d31b53 llvm::LoopVectorizePass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x3da4b53)
#19 0x000055cb59759fa6 llvm::detail::PassModel<llvm::Function, llvm::LoopVectorizePass, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x37ccfa6)
#20 0x000055cb57d7e6d1 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x1df16d1)
#21 0x000055cb56ea7d26 llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0xf1ad26)
#22 0x000055cb57d7d03d llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x1df003d)
#23 0x000055cb56ea86e6 llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0xf1b6e6)
#24 0x000055cb57d7ca71 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x1defa71)
#25 0x000055cb58558f73 (anonymous namespace)::EmitAssemblyHelper::RunOptimizationPipeline(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>&, std::unique_ptr<llvm::ToolOutputFile, std::default_delete<llvm::ToolOutputFile>>&, clang::BackendConsumer*) BackendUtil.cpp:0:0
#26 0x000055cb5855c4cd 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>>, clang::BackendConsumer*) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x25cf4cd)
#27 0x000055cb58c3a64c clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x2cad64c)
#28 0x000055cb5aba792c clang::ParseAST(clang::Sema&, bool, bool) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x4c1a92c)
#29 0x000055cb58c3aa68 clang::CodeGenAction::ExecuteAction() (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x2cada68)
#30 0x000055cb58f02939 clang::FrontendAction::Execute() (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x2f75939)
#31 0x000055cb58e7ee4e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x2ef1e4e)
#32 0x000055cb58fef236 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x3062236)
#33 0x000055cb56e2c175 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0xe9f175)
#34 0x000055cb56e23efa ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#35 0x000055cb58c80b2d 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
#36 0x000055cb582131f0 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x22861f0)
#37 0x000055cb58c8114f clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#38 0x000055cb58c44c64 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x2cb7c64)
#39 0x000055cb58c45d7d clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x2cb8d7d)
#40 0x000055cb58c4de95 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0x2cc0e95)
#41 0x000055cb56e2910b clang_main(int, char**, llvm::ToolContext const&) (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0xe9c10b)
#42 0x000055cb56d5906b main (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0xdcc06b)
#43 0x00007f00f3c95083 __libc_start_main /build/glibc-LcI20x/glibc-2.31/csu/../csu/libc-start.c:342:3
#44 0x000055cb56e2398e _start (/home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin/clang+0xe9698e)
clang: error: clang frontend command failed with exit code 134 (use -v to see invocation)
clang version 20.0.0 (https://github.com/llvm/llvm-project.git 8ec406757cb92f352888a3d4092397f2b5a7d1d9)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/dyung/src/upstream/8ec406757cb92f352888a3d4092397f2b5a7d1d9-linux/bin
Build config: +assertions

I bisected this back to commit 8ec4067.

[fhahn]

Thanks for the reports, should be fixed now