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[clang] Crash at -O3: Assertion `MA->use_empty() && "Trying to remove memory access that still has uses"' failed #116228

Open cardigan1008 opened 4 days ago

cardigan1008 commented 4 days ago

When I compiled the code with -O3, it crashed:

Bisected to https://github.com/llvm/llvm-project/commit/5a3e3675f6be3c49fb1a305202888cce4d916ba6, which was committed by @durin42

Compiler explorer: https://godbolt.org/z/3Wc1jdx6d

struct a {
  struct a *b
};
int c, g, i;
void *malloc();
int d() {
  struct a *e = malloc(c);
  if (e == 0)
    return 1;
  for (int f = 0; f < c; f++)
    e[f].b = 1 ? &e[1] : 0;
}
int h() {
  for (; g; g++)
    ;
  return 0;
}
void j() {
  for (;;)
    for (; h() + i; i++)
      d();
}
int main() {}

Crash is: 

clang: /root/llvm-project/llvm/lib/Analysis/MemorySSA.cpp:1840: void llvm::MemorySSA::removeFromLookups(llvm::MemoryAccess*): Assertion `MA->use_empty() && "Trying to remove memory access that still has 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: /opt/compiler-explorer/clang-assertions-trunk/bin/clang -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -O3 -Wall -Wextra <source>
1.  <eof> parser at end of file
2.  Optimizer
3.  Running pass "require<globals-aa>,function(invalidate<aa>),require<profile-summary>,cgscc(devirt<4>(inline,function-attrs<skip-non-recursive-function-attrs>,argpromotion,openmp-opt-cgscc,function<eager-inv;no-rerun>(sroa<modify-cfg>,early-cse<memssa>,speculative-execution<only-if-divergent-target>,jump-threading,correlated-propagation,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,instcombine<max-iterations=1;no-verify-fixpoint>,aggressive-instcombine,libcalls-shrinkwrap,tailcallelim,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,reassociate,constraint-elimination,loop-mssa(loop-instsimplify,loop-simplifycfg,licm<no-allowspeculation>,loop-rotate<header-duplication;no-prepare-for-lto>,licm<allowspeculation>,simple-loop-unswitch<nontrivial;trivial>),simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,instcombine<max-iterations=1;no-verify-fixpoint>,loop(loop-idiom,indvars,simple-loop-unswitch<nontrivial;trivial>,loop-deletion,loop-unroll-full),sroa<modify-cfg>,vector-combine,mldst-motion<no-split-footer-bb>,gvn<>,sccp,bdce,instcombine<max-iterations=1;no-verify-fixpoint>,jump-threading,correlated-propagation,adce,memcpyopt,dse,move-auto-init,loop-mssa(licm<allowspeculation>),coro-elide,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,instcombine<max-iterations=1;no-verify-fixpoint>),function-attrs,function(require<should-not-run-function-passes>),coro-split,coro-annotation-elide)),function(invalidate<should-not-run-function-passes>),cgscc(devirt<4>())" on module "<source>"
4.  Running pass "cgscc(devirt<4>(inline,function-attrs<skip-non-recursive-function-attrs>,argpromotion,openmp-opt-cgscc,function<eager-inv;no-rerun>(sroa<modify-cfg>,early-cse<memssa>,speculative-execution<only-if-divergent-target>,jump-threading,correlated-propagation,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,instcombine<max-iterations=1;no-verify-fixpoint>,aggressive-instcombine,libcalls-shrinkwrap,tailcallelim,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,reassociate,constraint-elimination,loop-mssa(loop-instsimplify,loop-simplifycfg,licm<no-allowspeculation>,loop-rotate<header-duplication;no-prepare-for-lto>,licm<allowspeculation>,simple-loop-unswitch<nontrivial;trivial>),simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,instcombine<max-iterations=1;no-verify-fixpoint>,loop(loop-idiom,indvars,simple-loop-unswitch<nontrivial;trivial>,loop-deletion,loop-unroll-full),sroa<modify-cfg>,vector-combine,mldst-motion<no-split-footer-bb>,gvn<>,sccp,bdce,instcombine<max-iterations=1;no-verify-fixpoint>,jump-threading,correlated-propagation,adce,memcpyopt,dse,move-auto-init,loop-mssa(licm<allowspeculation>),coro-elide,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,instcombine<max-iterations=1;no-verify-fixpoint>),function-attrs,function(require<should-not-run-function-passes>),coro-split,coro-annotation-elide))" on module "<source>"
5.  Running pass "loop-mssa(loop-instsimplify,loop-simplifycfg,licm<no-allowspeculation>,loop-rotate<header-duplication;no-prepare-for-lto>,licm<allowspeculation>,simple-loop-unswitch<nontrivial;trivial>)" on function "j"
 #0 0x0000000003bfb838 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3bfb838)
 #1 0x0000000003bf953c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3bf953c)
 #2 0x0000000003b46b38 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007afb46242520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007afb462969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x00007afb46242476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x00007afb462287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x00007afb4622871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #8 0x00007afb46239e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #9 0x0000000002bead0a llvm::MemorySSA::removeFromLookups(llvm::MemoryAccess*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x2bead0a)
#10 0x0000000002c03a6c llvm::MemorySSAUpdater::removeBlocks(llvm::SmallSetVector<llvm::BasicBlock*, 8u> const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x2c03a6c)
#11 0x00000000084e163a deleteDeadBlocksFromLoop(llvm::Loop&, llvm::SmallVectorImpl<llvm::BasicBlock*>&, llvm::DominatorTree&, llvm::LoopInfo&, llvm::MemorySSAUpdater*, llvm::ScalarEvolution*, llvm::LPMUpdater&) SimpleLoopUnswitch.cpp:0:0
#12 0x00000000084ea50d unswitchNontrivialInvariants(llvm::Loop&, llvm::Instruction&, llvm::ArrayRef<llvm::Value*>, llvm::IVConditionInfo&, llvm::DominatorTree&, llvm::LoopInfo&, llvm::AssumptionCache&, llvm::ScalarEvolution*, llvm::MemorySSAUpdater*, llvm::LPMUpdater&, bool, bool) SimpleLoopUnswitch.cpp:0:0
#13 0x00000000084ec9a8 unswitchBestCondition(llvm::Loop&, llvm::DominatorTree&, llvm::LoopInfo&, llvm::AssumptionCache&, llvm::AAResults&, llvm::TargetTransformInfo&, llvm::ScalarEvolution*, llvm::MemorySSAUpdater*, llvm::LPMUpdater&) SimpleLoopUnswitch.cpp:0:0
#14 0x00000000084f0679 llvm::SimpleLoopUnswitchPass::run(llvm::Loop&, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>&, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x84f0679)
#15 0x000000000525730e llvm::detail::PassModel<llvm::Loop, llvm::SimpleLoopUnswitchPass, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>::run(llvm::Loop&, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>&, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x525730e)
#16 0x0000000003a12986 std::optional<llvm::PreservedAnalyses> llvm::PassManager<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>::runSinglePass<llvm::Loop, std::unique_ptr<llvm::detail::PassConcept<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>, std::default_delete<llvm::detail::PassConcept<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>>>>(llvm::Loop&, std::unique_ptr<llvm::detail::PassConcept<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>, std::default_delete<llvm::detail::PassConcept<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>>>&, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>&, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&, llvm::PassInstrumentation&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3a12986)
#17 0x0000000003a12b4e llvm::PassManager<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>::runWithoutLoopNestPasses(llvm::Loop&, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>&, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3a12b4e)
#18 0x0000000003a13f04 llvm::PassManager<llvm::Loop, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&>::run(llvm::Loop&, llvm::AnalysisManager<llvm::Loop, llvm::LoopStandardAnalysisResults&>&, llvm::LoopStandardAnalysisResults&, llvm::LPMUpdater&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3a13f04)
#19 0x0000000003a14bfc llvm::FunctionToLoopPassAdaptor::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3a14bfc)
#20 0x000000000112567e llvm::detail::PassModel<llvm::Function, llvm::FunctionToLoopPassAdaptor, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x112567e)
#21 0x00000000035b06d8 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x35b06d8)
#22 0x0000000001125c2e llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x1125c2e)
#23 0x0000000002ab3c12 llvm::CGSCCToFunctionPassAdaptor::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x2ab3c12)
#24 0x000000000112607e llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::CGSCCToFunctionPassAdaptor, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x112607e)
#25 0x0000000002aaad52 llvm::PassManager<llvm::LazyCallGraph::SCC, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x2aaad52)
#26 0x00000000052560ce llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::PassManager<llvm::LazyCallGraph::SCC, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x52560ce)
#27 0x0000000002ab0666 llvm::DevirtSCCRepeatedPass::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x2ab0666)
#28 0x00000000052560ee llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::DevirtSCCRepeatedPass, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x52560ee)
#29 0x0000000002aae3f6 llvm::ModuleToPostOrderCGSCCPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x2aae3f6)
#30 0x00000000052560ae llvm::detail::PassModel<llvm::Module, llvm::ModuleToPostOrderCGSCCPassAdaptor, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x52560ae)
#31 0x00000000035aeb30 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x35aeb30)
#32 0x0000000005476f75 llvm::ModuleInlinerWrapperPass::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5476f75)
#33 0x00000000050f42ce llvm::detail::PassModel<llvm::Module, llvm::ModuleInlinerWrapperPass, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x50f42ce)
#34 0x00000000035aeb30 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x35aeb30)
#35 0x0000000003ea671b (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
#36 0x0000000003ea9f45 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*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3ea9f45)
#37 0x0000000004575cfe clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4575cfe)
#38 0x000000000673552c clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x673552c)
#39 0x00000000045760e8 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x45760e8)
#40 0x00000000048312c9 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x48312c9)
#41 0x00000000047b04be clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x47b04be)
#42 0x000000000491c2ce clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x491c2ce)
#43 0x0000000000ceb57f cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xceb57f)
#44 0x0000000000ce323a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#45 0x00000000045b92e9 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
#46 0x0000000003b46fe4 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3b46fe4)
#47 0x00000000045b98df 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
#48 0x000000000457fbcd clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x457fbcd)
#49 0x0000000004580cbd clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4580cbd)
#50 0x0000000004588075 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4588075)
#51 0x0000000000ce8419 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xce8419)
#52 0x0000000000bb4c14 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xbb4c14)
#53 0x00007afb46229d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#54 0x00007afb46229e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#55 0x0000000000ce2cee _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xce2cee)
dtcxzyw commented 4 days ago

Reduced reproducer: https://godbolt.org/z/bK3z9nGsa

; bin/opt  -passes="loop-mssa(licm,simple-loop-unswitch<nontrivial;trivial>)" reduced.ll -S
; ModuleID = 'reduced.bc'
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

; Function Attrs: allockind("alloc,uninitialized")
declare ptr @malloc() #0

define void @j(i1 %cmp2.i) {
entry:
  br label %for.cond

for.cond:                                         ; preds = %for.cond1.for.cond_crit_edge, %entry
  br label %for.cond1

for.cond1:                                        ; preds = %for.body.i, %for.body, %for.cond
  br i1 false, label %for.cond1.for.cond_crit_edge, label %for.body

for.cond1.for.cond_crit_edge:                     ; preds = %for.cond1
  br label %for.cond

for.body:                                         ; preds = %for.cond1
  %call.i = call ptr @malloc()
  %cmp.i = icmp ne ptr %call.i, null
  %or.cond.i = select i1 %cmp.i, i1 %cmp2.i, i1 false
  br i1 %or.cond.i, label %for.body.i, label %for.cond1

for.body.i:                                       ; preds = %for.body
  br label %for.cond1
}

attributes #0 = { allockind("alloc,uninitialized") }