[llvm] r359879 - [CodeGenPrepare] limit overflow intrinsic matching to a single basic block

Sanjay Patel via llvm-commits llvm-commits at lists.llvm.org
Fri May 3 10:41:14 PDT 2019


Thank you for the revert and test. Sorry about the bug.

On Fri, May 3, 2019 at 11:36 AM Evgenii Stepanov <eugeni.stepanov at gmail.com>
wrote:

> $ bin/llc 2.bc
>
> attempting to delete unknown value kind
> UNREACHABLE executed at ../llvm-project/llvm/lib/IR/Value.cpp:120!
> Stack dump:
> 0. Program arguments: bin/llc 2.bc
> 1. Running pass 'Function Pass Manager' on module '2.bc'.
> 2. Running pass 'CodeGen Prepare' on function
>
> '@_ZN12_GLOBAL__N_117CommandLineParser23ParseCommandLineOptionsEiPKPKcN4llvm9StringRefEPNS5_11raw_ostreamE'
>  #0 0x0000000002218c9d PrintStackTraceSignalHandler(void*)
> (bin/llc+0x2218c9d)
>  #1 0x00000000022169ce llvm::sys::RunSignalHandlers() (bin/llc+0x22169ce)
>  #2 0x0000000002218e58 SignalHandler(int) (bin/llc+0x2218e58)
>  #3 0x00007f7b98c1b0c0 __restore_rt
> (/lib/x86_64-linux-gnu/libpthread.so.0+0x110c0)
>  #4 0x00007f7b97ddefcf raise (/lib/x86_64-linux-gnu/libc.so.6+0x32fcf)
>  #5 0x00007f7b97de03fa abort (/lib/x86_64-linux-gnu/libc.so.6+0x343fa)
>  #6 0x00000000021b31c7 (bin/llc+0x21b31c7)
>  #7 0x00000000020df85a (bin/llc+0x20df85a)
>  #8 0x00000000018f75bc (anonymous
> namespace)::CodeGenPrepare::runOnFunction(llvm::Function&)
> (bin/llc+0x18f75bc)
>  #9 0x0000000002097496
> llvm::FPPassManager::runOnFunction(llvm::Function&)
> (bin/llc+0x2097496)
> #10 0x00000000020977a3 llvm::FPPassManager::runOnModule(llvm::Module&)
> (bin/llc+0x20977a3)
> #11 0x0000000002097dec
> llvm::legacy::PassManagerImpl::run(llvm::Module&) (bin/llc+0x2097dec)
> #12 0x000000000174a9a6 compileModule(char**, llvm::LLVMContext&)
> (bin/llc+0x174a9a6)
> #13 0x000000000174845d main (bin/llc+0x174845d)
> #14 0x00007f7b97dcc2b1 __libc_start_main
> (/lib/x86_64-linux-gnu/libc.so.6+0x202b1)
> #15 0x000000000174802a _start (bin/llc+0x174802a)
> Aborted
>
> On Fri, May 3, 2019 at 10:28 AM Evgenii Stepanov
> <eugeni.stepanov at gmail.com> wrote:
> >
> > Confirmed in a local build. Reverting. I'll prepare a test case later.
> >
> > On Fri, May 3, 2019 at 10:13 AM Evgenii Stepanov
> > <eugeni.stepanov at gmail.com> wrote:
> > >
> > > Hi,
> > >
> > > this crash might be caused by this commit:
> > >
> > >
> http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap-ubsan/builds/12660/steps/build%20clang%2Fubsan/logs/stdio
> > >
> > > 0. Program arguments:
> > > /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9
> > > -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -disable-free
> > > -main-file-name CommandLine.cpp -mrelocation-model pic -pic-level 2
> > > -mthread-model posix -mdisable-fp-elim -fmath-errno -masm-verbose
> > > -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu
> > > x86-64 -dwarf-column-info -debug-info-kind=line-tables-only
> > > -dwarf-version=4 -debugger-tuning=gdb -momit-leaf-frame-pointer
> > > -ffunction-sections -fdata-sections -coverage-notes-file
> > >
> /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/lib/Support/CMakeFiles/LLVMSupport.dir/CommandLine.cpp.gcno
> > > -resource-dir
> /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/lib/clang/9.0.0
> > > -dependency-file
> > > lib/Support/CMakeFiles/LLVMSupport.dir/CommandLine.cpp.o.d
> > > -sys-header-deps -MT
> > > lib/Support/CMakeFiles/LLVMSupport.dir/CommandLine.cpp.o -D
> > > GTEST_HAS_RTTI=0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D
> > > __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I lib/Support -I
> > > /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm/lib/Support -I
> > > /usr/include/libxml2 -I include -I
> > > /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm/include -U NDEBUG
> > > -internal-isystem
> > > /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0
> > > -internal-isystem
> > >
> /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0
> > > -internal-isystem
> > >
> /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0
> > > -internal-isystem
> > >
> /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward
> > > -internal-isystem /usr/local/include -internal-isystem
> > >
> /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/lib/clang/9.0.0/include
> > > -internal-externc-isystem /usr/include/x86_64-linux-gnu
> > > -internal-externc-isystem /include -internal-externc-isystem
> > > /usr/include -O3 -Werror=date-time -Werror=unguarded-availability-new
> > > -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual
> > > -Wmissing-field-initializers -Wno-long-long -Wimplicit-fallthrough
> > > -Wcovered-switch-default -Wno-class-memaccess -Wno-noexcept-type
> > > -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wstring-conversion
> > > -pedantic -w -std=c++11 -fdeprecated-macro -fdebug-compilation-dir
> > > /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan
> > > -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden
> > >
> -fsanitize=alignment,array-bounds,bool,builtin,enum,float-cast-overflow,float-divide-by-zero,integer-divide-by-zero,nonnull-attribute,null,object-size,pointer-overflow,return,returns-nonnull-attribute,shift-base,shift-exponent,signed-integer-overflow,unreachable,vla-bound
> > >
> -fsanitize-blacklist=/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm/utils/sanitizers/ubsan_blacklist.txt
> > >
> -fdepfile-entry=/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm/utils/sanitizers/ubsan_blacklist.txt
> > > -fno-rtti -fobjc-runtime=gcc -fdiagnostics-show-option
> > > -fcolor-diagnostics -vectorize-loops -vectorize-slp -o
> > > lib/Support/CMakeFiles/LLVMSupport.dir/CommandLine.cpp.o -x c++
> > >
> /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm/lib/Support/CommandLine.cpp
> > > -faddrsig
> > > 1. <eof> parser at end of file
> > > 2. Code generation
> > > 3. Running pass 'Function Pass Manager' on module
> > >
> '/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm/lib/Support/CommandLine.cpp'.
> > > 4. Running pass 'CodeGen Prepare' on function
> > >
> '@_ZN12_GLOBAL__N_117CommandLineParser23ParseCommandLineOptionsEiPKPKcN4llvm9StringRefEPNS5_11raw_ostreamE'
> > >  #0 0x000055d2f954521a llvm::sys::PrintStackTrace(llvm::raw_ostream&)
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x298521a)
> > >  #1 0x000055d2f9543175 llvm::sys::RunSignalHandlers()
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x2983175)
> > >  #2 0x000055d2f954328c SignalHandler(int)
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x298328c)
> > >  #3 0x00007f0bd09f40e0 __restore_rt
> > > (/lib/x86_64-linux-gnu/libpthread.so.0+0x110e0)
> > >  #4 0x000055d2f8fb84f0
> > > llvm::ReplaceableMetadataImpl::getIfExists(llvm::Metadata&)
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x23f84f0)
> > >  #5 0x000055d2f8fb8569 llvm::MetadataTracking::untrack(void*,
> > > llvm::Metadata&)
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x23f8569)
> > >  #6 0x000055d2f8f742b4 llvm::Instruction::~Instruction()
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x23b42b4)
> > >  #7 0x000055d2f8fef140 llvm::Value::deleteValue()
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x242f140)
> > >  #8 0x000055d2f8b53944 (anonymous
> > > namespace)::CodeGenPrepare::runOnFunction(llvm::Function&)
> > > (.part.1278)
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x1f93944)
> > >  #9 0x000055d2f8fa8710
> > > llvm::FPPassManager::runOnFunction(llvm::Function&)
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x23e8710)
> > > #10 0x000055d2f8fa892c llvm::FPPassManager::runOnModule(llvm::Module&)
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x23e892c)
> > > #11 0x000055d2f8fa9454
> > > llvm::legacy::PassManagerImpl::run(llvm::Module&)
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x23e9454)
> > > #12 0x000055d2f973ed37 (anonymous
> > > namespace)::EmitAssemblyHelper::EmitAssembly(clang::BackendAction,
> > > std::unique_ptr<llvm::raw_pwrite_stream,
> > > std::default_delete<llvm::raw_pwrite_stream> >)
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x2b7ed37)
> > > #13 0x000055d2f974063c
> > > 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> >)
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x2b8063c)
> > > #14 0x000055d2fa11f628
> > > clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&)
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x355f628)
> > > #15 0x000055d2fa982319 clang::ParseAST(clang::Sema&, bool, bool)
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x3dc2319)
> > > #16 0x000055d2fa11e8b9 clang::CodeGenAction::ExecuteAction()
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x355e8b9)
> > > #17 0x000055d2f9bcfbbe clang::FrontendAction::Execute()
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x300fbbe)
> > > #18 0x000055d2f9b97b96
> > > clang::CompilerInstance::ExecuteAction(clang::FrontendAction&)
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x2fd7b96)
> > > #19 0x000055d2f9c73271
> > > clang::ExecuteCompilerInvocation(clang::CompilerInstance*)
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0x30b3271)
> > > #20 0x000055d2f7a5db77 cc1_main(llvm::ArrayRef<char const*>, char
> > > const*, void*)
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0xe9db77)
> > > #21 0x000055d2f79c812d main
> > >
> (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build0/bin/clang-9+0xe0812d)
> > >
> > >
> > > On Fri, May 3, 2019 at 6:06 AM Sanjay Patel via llvm-commits
> > > <llvm-commits at lists.llvm.org> wrote:
> > > >
> > > > Author: spatel
> > > > Date: Fri May  3 06:09:18 2019
> > > > New Revision: 359879
> > > >
> > > > URL: http://llvm.org/viewvc/llvm-project?rev=359879&view=rev
> > > > Log:
> > > > [CodeGenPrepare] limit overflow intrinsic matching to a single basic
> block
> > > >
> > > > Using/updating a dominator tree to match math overflow patterns may
> be very
> > > > expensive in compile-time (because of the way CGP uses a DT), so
> just handle
> > > > the single-block case.
> > > >
> > > > Also, we were restarting the iterator loops when doing the overflow
> intrinsic
> > > > transforms by marking the dominator tree for update. That was done
> to prevent
> > > > iterating over a removed instruction. But we can postpone the
> deletion using
> > > > the existing "RemovedInsts" structure, and that means we don't need
> to update
> > > > the DT.
> > > >
> > > > See post-commit thread for rL354298 for more details:
> > > >
> http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190422/646276.html
> > > >
> > > > Differential Revision: https://reviews.llvm.org/D61075
> > > >
> > > > Modified:
> > > >     llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp
> > > >     llvm/trunk/test/CodeGen/X86/cgp-usubo.ll
> > > >
>  llvm/trunk/test/Transforms/CodeGenPrepare/X86/optimizeSelect-DT.ll
> > > >
>  llvm/trunk/test/Transforms/CodeGenPrepare/X86/overflow-intrinsics.ll
> > > >
> > > > Modified: llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp
> > > > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp?rev=359879&r1=359878&r2=359879&view=diff
> > > >
> ==============================================================================
> > > > --- llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp (original)
> > > > +++ llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp Fri May  3 06:09:18
> 2019
> > > > @@ -388,9 +388,9 @@ class TypePromotionTransaction;
> > > >      bool tryToSinkFreeOperands(Instruction *I);
> > > >      bool replaceMathCmpWithIntrinsic(BinaryOperator *BO, CmpInst
> *Cmp,
> > > >                                       Intrinsic::ID IID);
> > > > -    bool optimizeCmp(CmpInst *Cmp, bool &ModifiedDT);
> > > > -    bool combineToUSubWithOverflow(CmpInst *Cmp, bool &ModifiedDT);
> > > > -    bool combineToUAddWithOverflow(CmpInst *Cmp, bool &ModifiedDT);
> > > > +    bool optimizeCmp(CmpInst *Cmp);
> > > > +    bool combineToUSubWithOverflow(CmpInst *Cmp);
> > > > +    bool combineToUAddWithOverflow(CmpInst *Cmp);
> > > >    };
> > > >
> > > >  } // end anonymous namespace
> > > > @@ -484,9 +484,13 @@ bool CodeGenPrepare::runOnFunction(Funct
> > > >      if (!LargeOffsetGEPMap.empty())
> > > >        MadeChange |= splitLargeGEPOffsets();
> > > >
> > > > -    // Really free removed instructions during promotion.
> > > > -    for (Instruction *I : RemovedInsts)
> > > > +    // Really free instructions removed during promotion or kept
> around to
> > > > +    // improve efficiency (see comments in overflow intrinsic
> transforms).
> > > > +    for (Instruction *I : RemovedInsts) {
> > > > +      if (I->getParent())
> > > > +        I->removeFromParent();
> > > >        I->deleteValue();
> > > > +    }
> > > >
> > > >      EverMadeChange |= MadeChange;
> > > >      SeenChainsForSExt.clear();
> > > > @@ -1177,6 +1181,20 @@ static bool OptimizeNoopCopyExpression(C
> > > >  bool CodeGenPrepare::replaceMathCmpWithIntrinsic(BinaryOperator *BO,
> > > >                                                   CmpInst *Cmp,
> > > >                                                   Intrinsic::ID IID)
> {
> > > > +  if (BO->getParent() != Cmp->getParent()) {
> > > > +    // We used to use a dominator tree here to allow multi-block
> optimization.
> > > > +    // But that was problematic because:
> > > > +    // 1. It could cause a perf regression by hoisting the math op
> into the
> > > > +    //    critical path.
> > > > +    // 2. It could cause a perf regression by creating a value that
> was live
> > > > +    //    across multiple blocks and increasing register pressure.
> > > > +    // 3. Use of a dominator tree could cause large compile-time
> regression.
> > > > +    //    This is because we recompute the DT on every change in
> the main CGP
> > > > +    //    run-loop. The recomputing is probably unnecessary in many
> cases, so if
> > > > +    //    that was fixed, using a DT here would be ok.
> > > > +    return false;
> > > > +  }
> > > > +
> > > >    // We allow matching the canonical IR (add X, C) back to (usubo
> X, -C).
> > > >    Value *Arg0 = BO->getOperand(0);
> > > >    Value *Arg1 = BO->getOperand(1);
> > > > @@ -1186,45 +1204,28 @@ bool CodeGenPrepare::replaceMathCmpWithI
> > > >      Arg1 = ConstantExpr::getNeg(cast<Constant>(Arg1));
> > > >    }
> > > >
> > > > -  Instruction *InsertPt;
> > > > -  if (BO->hasOneUse() && BO->user_back() == Cmp) {
> > > > -    // If the math is only used by the compare, insert at the
> compare to keep
> > > > -    // the condition in the same block as its users. (CGP
> aggressively sinks
> > > > -    // compares to help out SDAG.)
> > > > -    InsertPt = Cmp;
> > > > -  } else {
> > > > -    // The math and compare may be independent instructions. Check
> dominance to
> > > > -    // determine the insertion point for the intrinsic.
> > > > -    bool MathDominates = getDT(*BO->getFunction()).dominates(BO,
> Cmp);
> > > > -    if (!MathDominates && !getDT(*BO->getFunction()).dominates(Cmp,
> BO))
> > > > -      return false;
> > > > -
> > > > -    BasicBlock *MathBB = BO->getParent(), *CmpBB = Cmp->getParent();
> > > > -    if (MathBB != CmpBB) {
> > > > -      // Avoid hoisting an extra op into a dominating block and
> creating a
> > > > -      // potentially longer critical path.
> > > > -      if (!MathDominates)
> > > > -        return false;
> > > > -      // Check that the insertion doesn't create a value that is
> live across
> > > > -      // more than two blocks, so to minimise the increase in
> register pressure.
> > > > -      BasicBlock *Dominator = MathDominates ? MathBB : CmpBB;
> > > > -      BasicBlock *Dominated = MathDominates ? CmpBB : MathBB;
> > > > -      auto Successors = successors(Dominator);
> > > > -      if (llvm::find(Successors, Dominated) == Successors.end())
> > > > -        return false;
> > > > +  // Insert at the first instruction of the pair.
> > > > +  Instruction *InsertPt = nullptr;
> > > > +  for (Instruction &Iter : *Cmp->getParent()) {
> > > > +    if (&Iter == BO || &Iter == Cmp) {
> > > > +      InsertPt = &Iter;
> > > > +      break;
> > > >      }
> > > > -
> > > > -    InsertPt = MathDominates ? cast<Instruction>(BO) :
> cast<Instruction>(Cmp);
> > > >    }
> > > > +  assert(InsertPt != nullptr && "Parent block did not contain cmp
> or binop");
> > > >
> > > >    IRBuilder<> Builder(InsertPt);
> > > >    Value *MathOV = Builder.CreateBinaryIntrinsic(IID, Arg0, Arg1);
> > > >    Value *Math = Builder.CreateExtractValue(MathOV, 0, "math");
> > > >    Value *OV = Builder.CreateExtractValue(MathOV, 1, "ov");
> > > > +
> > > > +  // Delay the actual removal/deletion of the binop and compare for
> efficiency.
> > > > +  // If we delete those now, we would invalidate the instruction
> iterator and
> > > > +  // trigger dominator tree updates.
> > > >    BO->replaceAllUsesWith(Math);
> > > >    Cmp->replaceAllUsesWith(OV);
> > > > -  BO->eraseFromParent();
> > > > -  Cmp->eraseFromParent();
> > > > +  RemovedInsts.insert(BO);
> > > > +  RemovedInsts.insert(Cmp);
> > > >    return true;
> > > >  }
> > > >
> > > > @@ -1260,8 +1261,7 @@ static bool matchUAddWithOverflowConstan
> > > >
> > > >  /// Try to combine the compare into a call to the
> llvm.uadd.with.overflow
> > > >  /// intrinsic. Return true if any changes were made.
> > > > -bool CodeGenPrepare::combineToUAddWithOverflow(CmpInst *Cmp,
> > > > -                                               bool &ModifiedDT) {
> > > > +bool CodeGenPrepare::combineToUAddWithOverflow(CmpInst *Cmp) {
> > > >    Value *A, *B;
> > > >    BinaryOperator *Add;
> > > >    if (!match(Cmp, m_UAddWithOverflow(m_Value(A), m_Value(B),
> m_BinOp(Add))))
> > > > @@ -1281,13 +1281,10 @@ bool CodeGenPrepare::combineToUAddWithOv
> > > >    if (!replaceMathCmpWithIntrinsic(Add, Cmp,
> Intrinsic::uadd_with_overflow))
> > > >      return false;
> > > >
> > > > -  // Reset callers - do not crash by iterating over a dead
> instruction.
> > > > -  ModifiedDT = true;
> > > >    return true;
> > > >  }
> > > >
> > > > -bool CodeGenPrepare::combineToUSubWithOverflow(CmpInst *Cmp,
> > > > -                                               bool &ModifiedDT) {
> > > > +bool CodeGenPrepare::combineToUSubWithOverflow(CmpInst *Cmp) {
> > > >    // We are not expecting non-canonical/degenerate code. Just bail
> out.
> > > >    Value *A = Cmp->getOperand(0), *B = Cmp->getOperand(1);
> > > >    if (isa<Constant>(A) && isa<Constant>(B))
> > > > @@ -1342,8 +1339,6 @@ bool CodeGenPrepare::combineToUSubWithOv
> > > >    if (!replaceMathCmpWithIntrinsic(Sub, Cmp,
> Intrinsic::usub_with_overflow))
> > > >      return false;
> > > >
> > > > -  // Reset callers - do not crash by iterating over a dead
> instruction.
> > > > -  ModifiedDT = true;
> > > >    return true;
> > > >  }
> > > >
> > > > @@ -1413,14 +1408,14 @@ static bool sinkCmpExpression(CmpInst *C
> > > >    return MadeChange;
> > > >  }
> > > >
> > > > -bool CodeGenPrepare::optimizeCmp(CmpInst *Cmp, bool &ModifiedDT) {
> > > > +bool CodeGenPrepare::optimizeCmp(CmpInst *Cmp) {
> > > >    if (sinkCmpExpression(Cmp, *TLI))
> > > >      return true;
> > > >
> > > > -  if (combineToUAddWithOverflow(Cmp, ModifiedDT))
> > > > +  if (combineToUAddWithOverflow(Cmp))
> > > >      return true;
> > > >
> > > > -  if (combineToUSubWithOverflow(Cmp, ModifiedDT))
> > > > +  if (combineToUSubWithOverflow(Cmp))
> > > >      return true;
> > > >
> > > >    return false;
> > > > @@ -6945,7 +6940,7 @@ bool CodeGenPrepare::optimizeInst(Instru
> > > >    }
> > > >
> > > >    if (auto *Cmp = dyn_cast<CmpInst>(I))
> > > > -    if (TLI && optimizeCmp(Cmp, ModifiedDT))
> > > > +    if (TLI && optimizeCmp(Cmp))
> > > >        return true;
> > > >
> > > >    if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
> > > >
> > > > Modified: llvm/trunk/test/CodeGen/X86/cgp-usubo.ll
> > > > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/cgp-usubo.ll?rev=359879&r1=359878&r2=359879&view=diff
> > > >
> ==============================================================================
> > > > --- llvm/trunk/test/CodeGen/X86/cgp-usubo.ll (original)
> > > > +++ llvm/trunk/test/CodeGen/X86/cgp-usubo.ll Fri May  3 06:09:18 2019
> > > > @@ -121,7 +121,7 @@ define i1 @usubo_ne_constant0_op1_i32(i3
> > > >    ret i1 %ov
> > > >  }
> > > >
> > > > -; Verify insertion point for multi-BB.
> > > > +; This used to verify insertion point for multi-BB, but now we just
> bail out.
> > > >
> > > >  declare void @call(i1)
> > > >
> > > > @@ -131,14 +131,17 @@ define i1 @usubo_ult_sub_dominates_i64(i
> > > >  ; CHECK-NEXT:    testb $1, %cl
> > > >  ; CHECK-NEXT:    je .LBB8_2
> > > >  ; CHECK-NEXT:  # %bb.1: # %t
> > > > -; CHECK-NEXT:    subq %rsi, %rdi
> > > > -; CHECK-NEXT:    setb %al
> > > > -; CHECK-NEXT:    movq %rdi, (%rdx)
> > > > +; CHECK-NEXT:    movq %rdi, %rax
> > > > +; CHECK-NEXT:    subq %rsi, %rax
> > > > +; CHECK-NEXT:    movq %rax, (%rdx)
> > > >  ; CHECK-NEXT:    testb $1, %cl
> > > > -; CHECK-NEXT:    jne .LBB8_3
> > > > +; CHECK-NEXT:    je .LBB8_2
> > > > +; CHECK-NEXT:  # %bb.3: # %end
> > > > +; CHECK-NEXT:    cmpq %rsi, %rdi
> > > > +; CHECK-NEXT:    setb %al
> > > > +; CHECK-NEXT:    retq
> > > >  ; CHECK-NEXT:  .LBB8_2: # %f
> > > >  ; CHECK-NEXT:    movl %ecx, %eax
> > > > -; CHECK-NEXT:  .LBB8_3: # %end
> > > >  ; CHECK-NEXT:    retq
> > > >  entry:
> > > >    br i1 %cond, label %t, label %f
> > > >
> > > > Modified:
> llvm/trunk/test/Transforms/CodeGenPrepare/X86/optimizeSelect-DT.ll
> > > > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/CodeGenPrepare/X86/optimizeSelect-DT.ll?rev=359879&r1=359878&r2=359879&view=diff
> > > >
> ==============================================================================
> > > > ---
> llvm/trunk/test/Transforms/CodeGenPrepare/X86/optimizeSelect-DT.ll
> (original)
> > > > +++
> llvm/trunk/test/Transforms/CodeGenPrepare/X86/optimizeSelect-DT.ll Fri May
> 3 06:09:18 2019
> > > > @@ -14,11 +14,10 @@ define i1 @PR41004(i32 %x, i32 %y, i32 %
> > > >  ; CHECK-NEXT:    br label [[SELECT_END]]
> > > >  ; CHECK:       select.end:
> > > >  ; CHECK-NEXT:    [[MUL:%.*]] = phi i32 [ [[REM]],
> [[SELECT_TRUE_SINK]] ], [ 0, [[ENTRY:%.*]] ]
> > > > -; CHECK-NEXT:    [[TMP0:%.*]] = call { i32, i1 }
> @llvm.usub.with.overflow.i32(i32 [[T1:%.*]], i32 1)
> > > > -; CHECK-NEXT:    [[MATH:%.*]] = extractvalue { i32, i1 } [[TMP0]], 0
> > > > -; CHECK-NEXT:    [[OV:%.*]] = extractvalue { i32, i1 } [[TMP0]], 1
> > > > -; CHECK-NEXT:    [[ADD:%.*]] = add i32 [[MATH]], [[MUL]]
> > > > -; CHECK-NEXT:    ret i1 [[OV]]
> > > > +; CHECK-NEXT:    [[NEG:%.*]] = add i32 [[T1:%.*]], -1
> > > > +; CHECK-NEXT:    [[ADD:%.*]] = add i32 [[NEG]], [[MUL]]
> > > > +; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i32 [[T1]], 0
> > > > +; CHECK-NEXT:    ret i1 [[TOBOOL]]
> > > >  ;
> > > >  entry:
> > > >    %rem = srem i32 %x, 2
> > > >
> > > > Modified:
> llvm/trunk/test/Transforms/CodeGenPrepare/X86/overflow-intrinsics.ll
> > > > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/CodeGenPrepare/X86/overflow-intrinsics.ll?rev=359879&r1=359878&r2=359879&view=diff
> > > >
> ==============================================================================
> > > > ---
> llvm/trunk/test/Transforms/CodeGenPrepare/X86/overflow-intrinsics.ll
> (original)
> > > > +++
> llvm/trunk/test/Transforms/CodeGenPrepare/X86/overflow-intrinsics.ll Fri
> May  3 06:09:18 2019
> > > > @@ -47,15 +47,16 @@ define i64 @uaddo3(i64 %a, i64 %b) nounw
> > > >    ret i64 %Q
> > > >  }
> > > >
> > > > +; TODO? CGP sinks the compare before we have a chance to form the
> overflow intrinsic.
> > > > +
> > > >  define i64 @uaddo4(i64 %a, i64 %b, i1 %c) nounwind ssp {
> > > >  ; CHECK-LABEL: @uaddo4(
> > > >  ; CHECK-NEXT:  entry:
> > > > +; CHECK-NEXT:    [[ADD:%.*]] = add i64 [[B:%.*]], [[A:%.*]]
> > > >  ; CHECK-NEXT:    br i1 [[C:%.*]], label [[NEXT:%.*]], label
> [[EXIT:%.*]]
> > > >  ; CHECK:       next:
> > > > -; CHECK-NEXT:    [[TMP0:%.*]] = call { i64, i1 }
> @llvm.uadd.with.overflow.i64(i64 [[B:%.*]], i64 [[A:%.*]])
> > > > -; CHECK-NEXT:    [[MATH:%.*]] = extractvalue { i64, i1 } [[TMP0]], 0
> > > > -; CHECK-NEXT:    [[OV:%.*]] = extractvalue { i64, i1 } [[TMP0]], 1
> > > > -; CHECK-NEXT:    [[Q:%.*]] = select i1 [[OV]], i64 [[B]], i64 42
> > > > +; CHECK-NEXT:    [[TMP0:%.*]] = icmp ugt i64 [[B]], [[ADD]]
> > > > +; CHECK-NEXT:    [[Q:%.*]] = select i1 [[TMP0]], i64 [[B]], i64 42
> > > >  ; CHECK-NEXT:    ret i64 [[Q]]
> > > >  ; CHECK:       exit:
> > > >  ; CHECK-NEXT:    ret i64 0
> > > > @@ -362,7 +363,7 @@ define i1 @usubo_ne_constant0_op1_i32(i3
> > > >    ret i1 %ov
> > > >  }
> > > >
> > > > -; Verify insertion point for multi-BB.
> > > > +; This used to verify insertion point for multi-BB, but now we just
> bail out.
> > > >
> > > >  declare void @call(i1)
> > > >
> > > > @@ -371,15 +372,14 @@ define i1 @usubo_ult_sub_dominates_i64(i
> > > >  ; CHECK-NEXT:  entry:
> > > >  ; CHECK-NEXT:    br i1 [[COND:%.*]], label [[T:%.*]], label
> [[F:%.*]]
> > > >  ; CHECK:       t:
> > > > -; CHECK-NEXT:    [[TMP0:%.*]] = call { i64, i1 }
> @llvm.usub.with.overflow.i64(i64 [[X:%.*]], i64 [[Y:%.*]])
> > > > -; CHECK-NEXT:    [[MATH:%.*]] = extractvalue { i64, i1 } [[TMP0]], 0
> > > > -; CHECK-NEXT:    [[OV1:%.*]] = extractvalue { i64, i1 } [[TMP0]], 1
> > > > -; CHECK-NEXT:    store i64 [[MATH]], i64* [[P:%.*]]
> > > > +; CHECK-NEXT:    [[S:%.*]] = sub i64 [[X:%.*]], [[Y:%.*]]
> > > > +; CHECK-NEXT:    store i64 [[S]], i64* [[P:%.*]]
> > > >  ; CHECK-NEXT:    br i1 [[COND]], label [[END:%.*]], label [[F]]
> > > >  ; CHECK:       f:
> > > >  ; CHECK-NEXT:    ret i1 [[COND]]
> > > >  ; CHECK:       end:
> > > > -; CHECK-NEXT:    ret i1 [[OV1]]
> > > > +; CHECK-NEXT:    [[OV:%.*]] = icmp ult i64 [[X]], [[Y]]
> > > > +; CHECK-NEXT:    ret i1 [[OV]]
> > > >  ;
> > > >  entry:
> > > >    br i1 %cond, label %t, label %f
> > > >
> > > >
> > > > _______________________________________________
> > > > llvm-commits mailing list
> > > > llvm-commits at lists.llvm.org
> > > > https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
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