Linux: Assertion `BitWidth == RHS.BitWidth && "Comparison requires equal bit widths"' failed

[nickdesaulniers]

while confirming #1181 on mainline, I hit a new assertion failure:

$ ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- make CC=clang -j71 fs/cifs/smb2ops.o
...
clang-12: ../include/llvm/ADT/APInt.h:1151: bool llvm::APInt::operator==(const llvm::APInt &) const: Assertion `BitWidth == RHS.BitWidth && "Comparison requires equal bit widths"' 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: /android0/llvm-project/llvm/build/bin/clang-12 -cc1 -triple s390x-unknown-linux-gnu -S -disable-free -main-file-name smb2ops.c -mrelocation-model pic -pic-level 2 -fno-delete-null-pointer-checks -mllvm -warn-stack-size=1024 -mframe-pointer=none -relaxed-aliasing -fmath-errno -fno-rounding-math -no-integrated-as -mconstructor-aliases -target-cpu z196 -target-feature +soft-float -mbackchain -mpacked-stack -msoft-float -mfloat-abi soft -fno-split-dwarf-inlining -debug-info-kind=limited -dwarf-version=4 -debugger-tuning=gdb -nostdsysteminc -nobuiltininc -resource-dir /android0/llvm-project/llvm/build/lib/clang/12.0.0 -dependency-file fs/cifs/.smb2ops.o.d -MT fs/cifs/smb2ops.o -isystem /android0/llvm-project/llvm/build/lib/clang/12.0.0/include -include ./include/linux/kconfig.h -include ./include/linux/compiler_types.h -I ./arch/s390/include -I ./arch/s390/include/generated -I ./include -I ./arch/s390/include/uapi -I ./arch/s390/include/generated/uapi -I ./include/uapi -I ./include/generated/uapi -D __KERNEL__ -D __PACK_STACK -D CONFIG_AS_CFI_VAL_OFFSET=1 -D CC_USING_NOP_MCOUNT -D CC_USING_FENTRY -I fs/cifs -D MODULE -D KBUILD_BASENAME="smb2ops" -D KBUILD_MODNAME="cifs" -fmacro-prefix-map=./= -O2 -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs -Werror=implicit-function-declaration -Werror=implicit-int -Wno-format-security -Werror=unknown-warning-option -Wno-sign-compare -Wno-frame-address -Wno-address-of-packed-member -Wno-format-invalid-specifier -Wno-gnu -Wno-unused-const-variable -Wdeclaration-after-statement -Wvla -Wno-pointer-sign -Wno-array-bounds -Werror=date-time -Werror=incompatible-pointer-types -Wno-initializer-overrides -Wno-format -Wno-sign-compare -Wno-format-zero-length -Wno-pointer-to-enum-cast -Wno-tautological-constant-out-of-range-compare -std=gnu89 -fno-dwarf-directory-asm -fdebug-compilation-dir /android0/kernel-all -ferror-limit 19 -pg -mfentry -mnop-mcount -mrecord-mcount -fwrapv -fno-signed-char -fwchar-type=short -fno-signed-wchar -fgnuc-version=4.2.1 -fcolor-diagnostics -vectorize-loops -vectorize-slp -o /tmp/smb2ops-7c0051.s -x c fs/cifs/smb2ops.c 

1.      <eof> parser at end of file
2.      Per-module optimization passes
3.      Running pass 'CallGraph Pass Manager' on module 'fs/cifs/smb2ops.c'.
4.      Running pass 'Combine redundant instructions' on function '@smb2_query_symlink'

 #0 0x0000000003f65713 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/android0/llvm-project/llvm/build/bin/clang-12+0x3f65713)
 #1 0x0000000003f6346e llvm::sys::RunSignalHandlers() (/android0/llvm-project/llvm/build/bin/clang-12+0x3f6346e)
 #2 0x0000000003f65bd5 SignalHandler(int) (/android0/llvm-project/llvm/build/bin/clang-12+0x3f65bd5)
 #3 0x00007fc85d091140 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14140)
 #4 0x00007fc85cb69db1 raise ./signal/../sysdeps/unix/sysv/linux/raise.c:51:1
 #5 0x00007fc85cb53537 abort ./stdlib/abort.c:81:7
 #6 0x00007fc85cb5340f get_sysdep_segment_value ./intl/loadmsgcat.c:509:8
 #7 0x00007fc85cb5340f _nl_load_domain ./intl/loadmsgcat.c:970:34
 #8 0x00007fc85cb625b2 (/lib/x86_64-linux-gnu/libc.so.6+0x345b2)
 #9 0x0000000003abcdad llvm::InstCombinerImpl::foldOrOfICmps(llvm::ICmpInst*, llvm::ICmpInst*, llvm::BinaryOperator&) (/android0/llvm-project/llvm/build/bin/clang-12+0x3abcdad)
#10 0x0000000003ac3205 llvm::InstCombinerImpl::visitOr(llvm::BinaryOperator&) (/android0/llvm-project/llvm/build/bin/clang-12+0x3ac3205)
#11 0x0000000003a9b09d llvm::InstCombinerImpl::run() (/android0/llvm-project/llvm/build/bin/clang-12+0x3a9b09d)
#12 0x0000000003a9d328 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*) (/android0/llvm-project/llvm/build/bin/clang-12+0x3a9d328)
#13 0x0000000003a9ec51 llvm::InstructionCombiningPass::runOnFunction(llvm::Function&) (/android0/llvm-project/llvm/build/bin/clang-12+0x3a9ec51)
#14 0x000000000389ad18 llvm::FPPassManager::runOnFunction(llvm::Function&) (/android0/llvm-project/llvm/build/bin/clang-12+0x389ad18)
#15 0x000000000362da23 (anonymous namespace)::CGPassManager::runOnModule(llvm::Module&) (/android0/llvm-project/llvm/build/bin/clang-12+0x362da23)
#16 0x000000000389b3c7 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/android0/llvm-project/llvm/build/bin/clang-12+0x389b3c7)
#17 0x000000000418c7ba 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> >) (/android0/llvm-project/llvm/build/bin/clang-12+0x418c7ba)
#18 0x00000000049cb1ec clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/android0/llvm-project/llvm/build/bin/clang-12+0x49cb1ec)
#19 0x00000000059f4bc3 clang::ParseAST(clang::Sema&, bool, bool) (/android0/llvm-project/llvm/build/bin/clang-12+0x59f4bc3)
#20 0x00000000049163e3 clang::FrontendAction::Execute() (/android0/llvm-project/llvm/build/bin/clang-12+0x49163e3)
#21 0x000000000486c8c2 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/android0/llvm-project/llvm/build/bin/clang-12+0x486c8c2)
#22 0x00000000049c4ec2 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/android0/llvm-project/llvm/build/bin/clang-12+0x49c4ec2)
#23 0x00000000027e58f3 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/android0/llvm-project/llvm/build/bin/clang-12+0x27e58f3)
#24 0x00000000027e39bc ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) (/android0/llvm-project/llvm/build/bin/clang-12+0x27e39bc)
#25 0x00000000027e3717 main (/android0/llvm-project/llvm/build/bin/clang-12+0x27e3717)
#26 0x00007fc85cb54cca __libc_start_main ./csu/../csu/libc-start.c:308:16
#27 0x00000000027e05ea _start (/android0/llvm-project/llvm/build/bin/clang-12+0x27e05ea)

let me see if I can bisect this quickly, and get a reproducer. cc @uweigand

[nickdesaulniers]

$ git bisect log
# bad: [b3ccfa1e0ce74041a76ce802e3be7944eea57c41] [hwasan] Increase max allocation size to 1Tb.
# good: [e0567582b8b1def8656f4a5addce0909fa51c86e] [NFCI][SCEV] Always refer to enum SCEVTypes as enum, not integer
git bisect start 'HEAD' 'e0567582b8b1'
# good: [3be2b0d1a1e0b94e8586f695e8174f139f7a84d8] [yaml2obj][NFCI] - Address post commit comments for "[yaml2obj][ELF] - Simplify the code that performs sections validation."
git bisect good 3be2b0d1a1e0b94e8586f695e8174f139f7a84d8
# bad: [234c47ae2a8e1877de8c661d5bb862ba952eabf9] [clang][Basic] Make SourceLocation usable as key in hash maps, NFCI
git bisect bad 234c47ae2a8e1877de8c661d5bb862ba952eabf9
# bad: [e372a5f86f6488bb0c2593a665d51fdd3a97c6e4] [InstCombine] Add or((icmp ult/ule (A + C1), C3), (icmp ult/ule (A + C2), C3)) uniform vector support
git bisect bad e372a5f86f6488bb0c2593a665d51fdd3a97c6e4
# good: [e346ea990528d93758ed216c53b2ef86ea82ff72] [InstCombine] SimplifyDemandedUseBits - pass APInt by const reference. NFCI.
git bisect good e346ea990528d93758ed216c53b2ef86ea82ff72
# good: [29d1a494477d78f9c86564b851891702456ddffb] [flang] Document and use intrinsic subroutine argument intents
git bisect good 29d1a494477d78f9c86564b851891702456ddffb
# good: [229db3647491ed2b2706a9b9ce13a97e38be6fa0] [libc++] Make __shared_weak_count vtable consistent across all build configurations
git bisect good 229db3647491ed2b2706a9b9ce13a97e38be6fa0
# good: [db915f296f58cb28493356118e8f033c8daecc89] Revert "Revert "[gn build] (manually) port d09b08919ca""
git bisect good db915f296f58cb28493356118e8f033c8daecc89
# first bad commit: [e372a5f86f6488bb0c2593a665d51fdd3a97c6e4] [InstCombine] Add or((icmp ult/ule (A + C1), C3), (icmp ult/ule (A + C2), C3)) uniform vector support

e372a5f86f6488bb0c2593a665d51fdd3a97c6e4 is the first bad commit
commit e372a5f86f6488bb0c2593a665d51fdd3a97c6e4
Author: Simon Pilgrim <[email protected]>
Date:   Tue Oct 20 13:27:43 2020 +0100

    [InstCombine] Add or((icmp ult/ule (A + C1), C3), (icmp ult/ule (A + C2), C3)) uniform vector support

    Reapplied rGa704d8238c86 with a check for integer/integervector types to prevent matching with pointer types

 .../Transforms/InstCombine/InstCombineAndOrXor.cpp | 53 +++++++++++-----------
 llvm/test/Transforms/InstCombine/or.ll             | 10 ++--

[nickdesaulniers]

cc @rksimon https://github.com/llvm/llvm-project/commit/e372a5f86f6488bb0c2593a665d51fdd3a97c6e4

[nickdesaulniers]

test case:

// clang -O2 foo.c
int b;
long c;
int a(void);
void smb2_query_symlink(void) {
  if (a() < sizeof(int) || c < sizeof(int)) b;
}

[nickdesaulniers]

it's not a clean revert for e372a5f, some other patches will also need to be backed out unless we can fix-forward quickly.

[nickdesaulniers]

Looks like it should be reverted in 4de215ff187746ff02ffdc6bd56bb54d42cbfdca (TODO): confirm

[nickdesaulniers]

1000th bug closed 🥳