[llvm-bugs] [Bug 46139] New: A/F: `(UserVF || isPowerOf2_32(MaxVF)) && "MaxVF must be a power of 2"' failed

via llvm-bugs llvm-bugs at lists.llvm.org
Fri May 29 18:56:52 PDT 2020 

https://bugs.llvm.org/show_bug.cgi?id=46139

            Bug ID: 46139
           Summary: A/F: `(UserVF || isPowerOf2_32(MaxVF)) && "MaxVF must
                    be a power of 2"' failed
           Product: new-bugs
           Version: trunk
          Hardware: PC
                OS: Windows NT
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: new bugs
          Assignee: unassignedbugs at nondot.org
          Reporter: douglas_yung at playstation.sony.com
                CC: htmldeveloper at gmail.com, llvm-bugs at lists.llvm.org

After upstream change 840450549c9199150cbdee29acef756c19660ca1, the compiler
started hitting the assertion failure added in that commit when compiling one
of our internal tests. The assertion that is hit is:

clang-11:
/home/dyung/src/upstream/llvm_clean_git/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:5011:
llvm::Optional<unsigned int>
llvm::LoopVectorizationCostModel::computeMaxVF(unsigned int, unsigned int):
Assertion `(UserVF || isPowerOf2_32(MaxVF)) && "MaxVF must be a power of 2"'
failed.

To reproduce, compile the following code with "clang-c -O2 -mavx test.c"

/* test.c */
long double table [] = {
  0.0L,
};
long double
foo(long double x, long int n)
{
  for (; n < 0; n++) {
    x /= 2;
  }
  for (; n > 0; n--) {
    x *= 2;
  }
  return x;
}
int main()
{
  long int j;

  for (j = 0; j < 8; j++) {
    if( 0.0L == foo(table[0], j)) { return 1; }
  }

  return 0;
}
/* test.c */

When compiled with a compiler built from
02f6f1ebb1f16e7e324df5201ce7003a4d9f2570, the assertion failure happens and
gives the following stack trace:

clang-11:
/home/dyung/src/upstream/llvm_clean_git/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:5011:
llvm::Optional<unsigned int>
llvm::LoopVectorizationCostModel::computeMaxVF(unsigned int, unsigned int):
Assertion `(UserVF || isPowerOf2_32(MaxVF)) && "MaxVF must be a power of 2"'
failed.
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash
backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments:
/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11
-c -O2 -mavx test3a.c 
1.      <eof> parser at end of file
2.      Per-module optimization passes
3.      Running pass 'Function Pass Manager' on module 'test3a.c'.
4.      Running pass 'Loop Vectorization' on function '@main'
 #0 0x000055945c01f27e llvm::sys::PrintStackTrace(llvm::raw_ostream&)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x59e627e)
 #1 0x000055945c01cfd4 llvm::sys::RunSignalHandlers()
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x59e3fd4)
 #2 0x000055945c01d251 llvm::sys::CleanupOnSignal(unsigned long)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x59e4251)
 #3 0x000055945bf83f88 CrashRecoverySignalHandler(int)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x594af88)
 #4 0x00007f170fbd53c0 __restore_rt
(/lib/x86_64-linux-gnu/libpthread.so.0+0x153c0)
 #5 0x00007f170e0f118b raise
/build/glibc-YYA7BZ/glibc-2.31/signal/../sysdeps/unix/sysv/linux/raise.c:51:1
 #6 0x00007f170e0d0859 abort /build/glibc-YYA7BZ/glibc-2.31/stdlib/abort.c:81:7
 #7 0x00007f170e0d0729 get_sysdep_segment_value
/build/glibc-YYA7BZ/glibc-2.31/intl/loadmsgcat.c:509:8
 #8 0x00007f170e0d0729 _nl_load_domain
/build/glibc-YYA7BZ/glibc-2.31/intl/loadmsgcat.c:970:34
 #9 0x00007f170e0e1f36 (/lib/x86_64-linux-gnu/libc.so.6+0x36f36)
#10 0x000055945c1efb4b llvm::LoopVectorizationCostModel::computeMaxVF(unsigned
int, unsigned int)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x5bb6b4b)
#11 0x000055945c1efe54 llvm::LoopVectorizationPlanner::plan(unsigned int,
unsigned int)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x5bb6e54)
#12 0x000055945c1f281e llvm::LoopVectorizePass::processLoop(llvm::Loop*)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x5bb981e)
#13 0x000055945c1f5120 llvm::LoopVectorizePass::runImpl(llvm::Function&,
llvm::ScalarEvolution&, llvm::LoopInfo&, llvm::TargetTransformInfo&,
llvm::DominatorTree&, llvm::BlockFrequencyInfo&, llvm::TargetLibraryInfo*,
llvm::DemandedBits&, llvm::AAResults&, llvm::AssumptionCache&,
std::function<llvm::LoopAccessInfo const& (llvm::Loop&)>&,
llvm::OptimizationRemarkEmitter&, llvm::ProfileSummaryInfo*)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x5bbc120)
#14 0x000055945c1f55b7 (anonymous
namespace)::LoopVectorize::runOnFunction(llvm::Function&)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x5bbc5b7)
#15 0x000055945b834a2c llvm::FPPassManager::runOnFunction(llvm::Function&)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x51fba2c)
#16 0x000055945b8350d9 llvm::FPPassManager::runOnModule(llvm::Module&)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x51fc0d9)
#17 0x000055945b835487 llvm::legacy::PassManagerImpl::run(llvm::Module&)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x51fc487)
#18 0x000055945c75a86c 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/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x612186c)
#19 0x000055945cb46ea9
clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x650dea9)
#20 0x000055945dd62669 clang::ParseAST(clang::Sema&, bool, bool)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x7729669)
#21 0x000055945cb45918 clang::CodeGenAction::ExecuteAction()
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x650c918)
#22 0x000055945ca3b389 clang::FrontendAction::Execute()
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x6402389)
#23 0x000055945c99773e
clang::CompilerInstance::ExecuteAction(clang::FrontendAction&)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x635e73e)
#24 0x000055945cb10403
clang::ExecuteCompilerInvocation(clang::CompilerInstance*)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x64d7403)
#25 0x0000559459d454af cc1_main(llvm::ArrayRef<char const*>, char const*,
void*)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x370c4af)
#26 0x0000559459d3f2f8 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x37062f8)
#27 0x000055945c8595d9 void llvm::function_ref<void
()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef>
>, std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> >*, bool*) const::'lambda'()>(long)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x62205d9)
#28 0x000055945bf8410c
llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x594b10c)
#29 0x000055945c85a096
clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef>
>, std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> >*, bool*) const (.part.0)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x6221096)
#30 0x000055945c83003c
clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&,
clang::driver::Command const*&) const
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x61f703c)
#31 0x000055945c830976
clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&,
llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*> >&) const
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x61f7976)
#32 0x000055945c839c29
clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&,
llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*> >&)
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x6200c29)
#33 0x0000559459d42989 main
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x3709989)
#34 0x00007f170e0d20b3 __libc_start_main
/build/glibc-YYA7BZ/glibc-2.31/csu/../csu/libc-start.c:342:3
#35 0x0000559459d3ee4e _start
(/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin/clang-11+0x3705e4e)
clang-11: error: clang frontend command failed due to signal (use -v to see
invocation)
clang version 11.0.0 (https://github.com/llvm/llvm-project.git
02f6f1ebb1f16e7e324df5201ce7003a4d9f2570)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir:
/home/dyung/src/upstream/02f6f1ebb1f16e7e324df5201ce7003a4d9f2570-linux/bin

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