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<head>
<base href="https://bugs.llvm.org/">
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Instruction Combining loop"
href="https://bugs.llvm.org/show_bug.cgi?id=51220">51220</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Instruction Combining loop
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Backend: RISC-V
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>luismarques@lowrisc.org
</td>
</tr>
<tr>
<th>CC</th>
<td>asb@lowrisc.org, craig.topper@gmail.com, florian_hahn@apple.com, llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>This happens since commit 88241ffb5636 ([Passes] Move ADCE before DSE & LICM.)
$ cat test.c
float a;
double b;
void c() {
for (int d = 0; d < 9; ++d)
for (char e = 0; e < 24; ++e)
for (char f = 0; f < 106; ++f) {
for (short g = 0; g < 6; ++g)
;
++a;
}
a = b;
}
$ clang -O2 --target=riscv32 -c test.c
fatal error: error in backend: Instruction Combining seems stuck in an infinite
loop after 100 iterations.
PLEASE submit a bug report to <a href="https://bugs.llvm.org/">https://bugs.llvm.org/</a> and include the crash
backtrace, preprocessed source, and associated run script.
Stack dump:
0. Program arguments:
/home/luismarques/llvm-project/build/debug-all/bin/clang -O2 --target=riscv32
-c test.c
1. <eof> parser at end of file
2. Per-module optimization passes
3. Running pass 'Function Pass Manager' on module 'test.c'.
4. Running pass 'Combine redundant instructions' on function '@c'
#0 0x00007fdb35fe0c67 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int)
/home/luismarques/llvm-project/llvm/lib/Support/Unix/Signals.inc:563:11
#1 0x00007fdb35fe0e7b PrintStackTraceSignalHandler(void*)
/home/luismarques/llvm-project/llvm/lib/Support/Unix/Signals.inc:630:1
#2 0x00007fdb35fdf260 llvm::sys::RunSignalHandlers()
/home/luismarques/llvm-project/llvm/lib/Support/Signals.cpp:71:5
#3 0x00007fdb35fe041b llvm::sys::CleanupOnSignal(unsigned long)
/home/luismarques/llvm-project/llvm/lib/Support/Unix/Signals.inc:0:3
#4 0x00007fdb35e3a39e (anonymous
namespace)::CrashRecoveryContextImpl::HandleCrash(int, unsigned long)
/home/luismarques/llvm-project/llvm/lib/Support/CrashRecoveryContext.cpp:0:7
#5 0x00007fdb35e3a2c8 llvm::CrashRecoveryContext::HandleExit(int)
/home/luismarques/llvm-project/llvm/lib/Support/CrashRecoveryContext.cpp:442:3
#6 0x00007fdb35fd8e0b llvm::sys::Process::Exit(int)
/home/luismarques/llvm-project/llvm/lib/Support/Process.cpp:97:10
#7 0x000055b8ed41d6a4
(/home/luismarques/llvm-project/build/debug-all/bin/clang+0x496a4)
#8 0x00007fdb35e5f5d1 llvm::report_fatal_error(llvm::Twine const&, bool)
/home/luismarques/llvm-project/llvm/lib/Support/ErrorHandling.cpp:108:5
#9 0x00007fdb397c2daa combineInstructionsOverFunction(llvm::Function&,
llvm::InstCombineWorklist&, llvm::AAResults*, llvm::AssumptionCache&,
llvm::TargetLibraryInfo&, llvm::TargetTransformInfo&, llvm::DominatorTree&,
llvm::OptimizationRemarkEmitter&, llvm::BlockFrequencyInfo*,
llvm::ProfileSummaryInfo*, unsigned int, llvm::LoopInfo*)
/home/luismarques/llvm-project/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp:3879:9
#10 0x00007fdb397c3358
llvm::InstructionCombiningPass::runOnFunction(llvm::Function&)
/home/luismarques/llvm-project/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp:3978:3
#11 0x00007fdb369f144d llvm::FPPassManager::runOnFunction(llvm::Function&)
/home/luismarques/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1519:23
#12 0x00007fdb369f694f llvm::FPPassManager::runOnModule(llvm::Module&)
/home/luismarques/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1565:16
#13 0x00007fdb369f1dfa (anonymous
namespace)::MPPassManager::runOnModule(llvm::Module&)
/home/luismarques/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1634:23
#14 0x00007fdb369f190d llvm::legacy::PassManagerImpl::run(llvm::Module&)
/home/luismarques/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:615:16
#15 0x00007fdb369f6c51 llvm::legacy::PassManager::run(llvm::Module&)
/home/luismarques/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1761:3
#16 0x00007fdb3c73c4a2 (anonymous
namespace)::EmitAssemblyHelper::EmitAssembly(clang::BackendAction,
std::unique_ptr<llvm::raw_pwrite_stream,
std::default_delete<llvm::raw_pwrite_stream> >)
/home/luismarques/llvm-project/clang/lib/CodeGen/BackendUtil.cpp:981:3
#17 0x00007fdb3c738b49 clang::EmitBackendOutput(clang::DiagnosticsEngine&,
clang::HeaderSearchOptions const&, clang::CodeGenOptions const&,
clang::TargetOptions const&, clang::LangOptions const&, llvm::DataLayout
const&, llvm::Module*, clang::BackendAction,
std::unique_ptr<llvm::raw_pwrite_stream,
std::default_delete<llvm::raw_pwrite_stream> >)
/home/luismarques/llvm-project/clang/lib/CodeGen/BackendUtil.cpp:1670:5
#18 0x00007fdb3cda0a5f
clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&)
/home/luismarques/llvm-project/clang/lib/CodeGen/CodeGenAction.cpp:341:7
#19 0x00007fdb308535df clang::ParseAST(clang::Sema&, bool, bool)
/home/luismarques/llvm-project/clang/lib/Parse/ParseAST.cpp:178:12
#20 0x00007fdb3956eb0c clang::ASTFrontendAction::ExecuteAction()
/home/luismarques/llvm-project/clang/lib/Frontend/FrontendAction.cpp:1058:1
#21 0x00007fdb3cd9acc7 clang::CodeGenAction::ExecuteAction()
/home/luismarques/llvm-project/clang/lib/CodeGen/CodeGenAction.cpp:0:28
#22 0x00007fdb3956e439 clang::FrontendAction::Execute()
/home/luismarques/llvm-project/clang/lib/Frontend/FrontendAction.cpp:953:7
#23 0x00007fdb394d8827
clang::CompilerInstance::ExecuteAction(clang::FrontendAction&)
/home/luismarques/llvm-project/clang/lib/Frontend/CompilerInstance.cpp:989:23
#24 0x00007fdb3dd54e6e
clang::ExecuteCompilerInvocation(clang::CompilerInstance*)
/home/luismarques/llvm-project/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:278:8
#25 0x000055b8ed41d075 cc1_main(llvm::ArrayRef<char const*>, char const*,
void*) /home/luismarques/llvm-project/clang/tools/driver/cc1_main.cpp:240:13
#26 0x000055b8ed40ff9f ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&)
/home/luismarques/llvm-project/clang/tools/driver/driver.cpp:330:5
#27 0x00007fdb38f46115
clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef>
<span class="quote">>, std::__cxx11::basic_string<char, std::char_traits<char>,</span >
std::allocator<char> >*, bool*) const::$_1::operator()() const
/home/luismarques/llvm-project/clang/lib/Driver/Job.cpp:404:34
#28 0x00007fdb38f460e5 void llvm::function_ref<void
()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef>
<span class="quote">>, std::__cxx11::basic_string<char, std::char_traits<char>,</span >
std::allocator<char> >*, bool*) const::$_1>(long)
/home/luismarques/llvm-project/llvm/include/llvm/ADT/STLExtras.h:185:5
#29 0x00007fdb35e27a99 llvm::function_ref<void ()>::operator()() const
/home/luismarques/llvm-project/llvm/include/llvm/ADT/STLExtras.h:209:5
#30 0x00007fdb35e3a187
llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>)
/home/luismarques/llvm-project/llvm/lib/Support/CrashRecoveryContext.cpp:425:3
#31 0x00007fdb38f45354
clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef>
<span class="quote">>, std::__cxx11::basic_string<char, std::char_traits<char>,</span >
std::allocator<char> >*, bool*) const
/home/luismarques/llvm-project/clang/lib/Driver/Job.cpp:404:7
#32 0x00007fdb38edb25c
clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&,
clang::driver::Command const*&) const
/home/luismarques/llvm-project/clang/lib/Driver/Compilation.cpp:195:7
#33 0x00007fdb38edb455
clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&,
llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*> >&) const
/home/luismarques/llvm-project/clang/lib/Driver/Compilation.cpp:246:13
#34 0x00007fdb38efb8dc
clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&,
llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*> >&)
/home/luismarques/llvm-project/clang/lib/Driver/Driver.cpp:1513:7
#35 0x000055b8ed40f8e9 main
/home/luismarques/llvm-project/clang/tools/driver/driver.cpp:502:9
#36 0x00007fdb356a8b25 __libc_start_main (/usr/lib/libc.so.6+0x27b25)
#37 0x000055b8ed40e8ce _start
(/home/luismarques/llvm-project/build/debug-all/bin/clang+0x3a8ce)
clang-12: error: clang frontend command failed with exit code 70 (use -v to see
invocation)
clang version 12.0.0
Target: riscv32
Thread model: posix
InstalledDir: /home/luismarques/llvm-project/build/debug-all/bin</pre>
</div>
</p>
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