[PATCH] D92431: [SROA] Remove Dead Instructions while creating speculative instructions

Fri Dec 4 06:55:54 PST 2020

arnamoy10 added a comment.

Hello @lebedev.ri ;

Thanks for the suggestion, as per your suggestion, I did the modification in the `deleteDeadInstructions()` function as follows:

  bool SROA::deleteDeadInstructions( SmallPtrSetImpl<AllocaInst *> &DeletedAllocas) {
    bool Changed = false;
    while (!DeadInsts.empty()) {
      Instruction *I = dyn_cast_or_null<Instruction>(DeadInsts.pop_back_val());

      if (I == NULL) continue;

      LLVM_DEBUG(dbgs() << "Deleting dead instruction: " << *I << "\n");

      // If the instruction is an alloca, find the possible dbg.declare connected
      // to it, and remove it too. We must do this before calling RAUW or we will
      // not be able to find it.
      if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
        DeletedAllocas.insert(AI);
        for (DbgVariableIntrinsic *OldDII : FindDbgAddrUses(AI))
          OldDII->eraseFromParent();
      }
      I->replaceAllUsesWith(UndefValue::get(I->getType()));

      for (Use &Operand : I->operands())
        if (Instruction *U = dyn_cast<Instruction>(Operand)) {
          // Zero out the operand and see if it becomes trivially dead.
         Operand = nullptr;
          if (isInstructionTriviallyDead(U))
            DeadInsts.insert(U);
        }
      ++NumDeleted;

      I->eraseFromParent();
      Changed = true;
    }
    return Changed;
  }

Where I modified the definition of `DeadInsts` to use `WeakVH`

But I am getting the following error:

  clang-10: /home/a00567935/for_upload/llvm-project_1141/llvm/include/llvm/ADT/DenseMap.h:378: void llvm::DenseMapBase<DerivedT, KeyT, ValueT, KeyInfoT, BucketT>::moveFromOldBuckets(BucketT*, BucketT*) [with DerivedT = llvm::DenseMap<llvm::WeakVH, llvm::detail::DenseSetEmpty, llvm::DenseMapInfo<llvm::WeakVH>, llvm::detail::DenseSetPair<llvm::WeakVH> >; KeyT = llvm::WeakVH; ValueT = llvm::detail::DenseSetEmpty; KeyInfoT = llvm::DenseMapInfo<llvm::WeakVH>; BucketT = llvm::detail::DenseSetPair<llvm::WeakVH>]: Assertion `!FoundVal && "Key already in new map?"' failed.

  Stack dump:

  0.      Program arguments: /home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10 -cc1 -triple aarch64-unknown-linux-gnu -emit-obj -disable-free -main-file-name test.c -mrelocation-model static -mthread-model posix -mllvm -pass-remarks= -mllvm -pass-remarks-missed= -mllvm -pass-remarks-analysis= -mframe-pointer=non-leaf -fmath-errno -ffp-contract=fast -fno-rounding-math -masm-verbose -mconstructor-aliases -target-cpu tsv110 -target-feature +v8.2a -target-feature +fp-armv8 -target-feature +neon -target-feature +crc -target-feature +crypto -target-feature +dotprod -target-feature +fp16fml -target-feature +spe -target-feature +ras -target-feature +lse -target-feature +rdm -target-feature +complxnum -target-feature +fullfp16 -target-feature +sha2 -target-feature +aes -target-abi aapcs -fallow-half-arguments-and-returns -dwarf-column-info -fno-split-dwarf-inlining -debugger-tuning=gdb -resource-dir /home/a00567935/for_upload/llvm-project_1141/install/lib/clang/10.0.1 -internal-isystem /usr/local/include -internal-isystem /home/a00567935/for_upload/llvm-project_1141/install/lib/clang/10.0.1/include -internal-externc-isystem /include -internal-externc-isystem /usr/include -O3 -w -fdebug-compilation-dir /home/a00567935/bug/1141 -ferror-limit 19 -fmessage-length 0 -fno-signed-char -fgnuc-version=4.2.1 -fobjc-runtime=gcc -fdiagnostics-show-option -fcolor-diagnostics -vectorize-loops -vectorize-slp -faddrsig -o /tmp/test-2538e6.o -x c test.c

  1.      <eof> parser at end of file
  2.      Per-module optimization passes
  3.      Running pass 'CallGraph Pass Manager' on module 'test.c'.
  4.      Running pass 'SROA' on function '@g'

  #0 0x0000aaaabb35fd18 llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x2045d18)
  #1 0x0000aaaabb35dee0 llvm::sys::RunSignalHandlers() (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x2043ee0)
  #2 0x0000aaaabb35e6b0 SignalHandler(int) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x20446b0)
  #3 0x0000ffffb778c698 (linux-vdso.so.1+0x698)
  #4 0x0000ffffb7451140 raise (/lib64/libc.so.6+0x33140)
  #5 0x0000ffffb74524ec abort (/lib64/libc.so.6+0x344ec)
  #6 0x0000ffffb744a54c __assert_fail_base (/lib64/libc.so.6+0x2c54c)
  #7 0x0000ffffb744a5cc (/lib64/libc.so.6+0x2c5cc)
  #8 0x0000aaaabb25ffc0 llvm::DenseMap<llvm::WeakVH, llvm::detail::DenseSetEmpty, llvm::DenseMapInfo<llvm::WeakVH>, llvm::detail::DenseSetPair<llvm::WeakVH> >::grow(unsigned int) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x1f45fc0)
  #9 0x0000aaaabb260178 llvm::SetVector<llvm::WeakVH, llvm::SmallVector<llvm::WeakVH, 8u>, llvm::DenseSet<llvm::WeakVH, llvm::DenseMapInfo<llvm::WeakVH> > >::insert(llvm::WeakVH const&) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x1f46178)
  #10 0x0000aaaabb2624fc llvm::SROA::deleteDeadInstructions(llvm::SmallPtrSetImpl<llvm::AllocaInst*>&) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x1f484fc)
  #11 0x0000aaaabb26d3f8 llvm::SROA::runImpl(llvm::Function&, llvm::DominatorTree&, llvm::AssumptionCache&) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x1f533f8)
  #12 0x0000aaaabb26dcbc llvm::sroa::SROALegacyPass::runOnFunction(llvm::Function&) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x1f53cbc)
  #13 0x0000aaaabad26a6c llvm::FPPassManager::runOnFunction(llvm::Function&) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x1a0ca6c)
  #14 0x0000aaaabd46f164 (anonymous namespace)::CGPassManager::runOnModule(llvm::Module&) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x4155164)
  #15 0x0000aaaabad27730 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x1a0d730)
  #16 0x0000aaaabb55ddc8 (anonymous namespace)::EmitAssemblyHelper::EmitAssembly(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream> >) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x2243dc8)
  #17 0x0000aaaabb55efe4 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/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x2244fe4)
  #18 0x0000aaaabbf3e5d4 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x2c245d4)
  #19 0x0000aaaabc8953d4 clang::ParseAST(clang::Sema&, bool, bool) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x357b3d4)
  #20 0x0000aaaabbf3d670 clang::CodeGenAction::ExecuteAction() (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x2c23670)
  #21 0x0000aaaabba0de00 clang::FrontendAction::Execute() (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x26f3e00)
  #22 0x0000aaaabb9da140 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x26c0140
  #23 0x0000aaaabbac0d80 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0x27a6d80)
  #24 0x0000aaaab9edafbc cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0xbc0fbc)
  #25 0x0000aaaab9ed79f0 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0xbbd9f0)
  #26 0x0000aaaab9e7aad8 main (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0xb60ad8)
  #27 0x0000ffffb743eb20 __libc_start_main (/lib64/libc.so.6+0x20b20)
  #28 0x0000aaaab9ed74ec _start (/home/a00567935/for_upload/llvm-project_1141/install/bin/clang-10+0xbbd4ec)
  clang-10: error: unable to execute command: Aborted (core dumped)
  clang-10: error: clang frontend command failed due to signal (use -v to see invocation)

I think it is failing in the line `DeadInsts.insert(U);`

Could you please advise how to fix this?

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D92431/new/

https://reviews.llvm.org/D92431