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📄 AliasAnalysis.cpp(33.55 KB)
📄 AliasAnalysisEvaluator.cpp(15.64 KB)
📄 AliasAnalysisSummary.cpp(3.49 KB)
📄 AliasAnalysisSummary.h(10.17 KB)
📄 AliasSetTracker.cpp(25.86 KB)
📄 Analysis.cpp(5.29 KB)
📄 AssumeBundleQueries.cpp(7.96 KB)
📄 AssumptionCache.cpp(10.94 KB)
📄 BasicAliasAnalysis.cpp(85.81 KB)
📄 BlockFrequencyInfo.cpp(12.39 KB)
📄 BlockFrequencyInfoImpl.cpp(28.6 KB)
📄 BranchProbabilityInfo.cpp(43.48 KB)
📄 CFG.cpp(9.9 KB)
📄 CFGPrinter.cpp(11.2 KB)
📄 CFLAndersAliasAnalysis.cpp(33.01 KB)
📄 CFLGraph.h(21.23 KB)
📄 CFLSteensAliasAnalysis.cpp(13.24 KB)
📄 CGSCCPassManager.cpp(31.2 KB)
📄 CallGraph.cpp(12.86 KB)
📄 CallGraphSCCPass.cpp(26.31 KB)
📄 CallPrinter.cpp(9.48 KB)
📄 CaptureTracking.cpp(15.38 KB)
📄 CmpInstAnalysis.cpp(4.63 KB)
📄 CodeMetrics.cpp(6.99 KB)
📄 ConstantFolding.cpp(105.15 KB)
📄 CostModel.cpp(3.87 KB)
📄 DDG.cpp(11.29 KB)
📄 Delinearization.cpp(4.49 KB)
📄 DemandedBits.cpp(16.27 KB)
📄 DependenceAnalysis.cpp(150.78 KB)
📄 DependenceGraphBuilder.cpp(19.24 KB)
📄 DivergenceAnalysis.cpp(15.59 KB)
📄 DomPrinter.cpp(9.67 KB)
📄 DomTreeUpdater.cpp(15.21 KB)
📄 DominanceFrontier.cpp(3.2 KB)
📄 EHPersonalities.cpp(5.89 KB)
📄 GlobalsModRef.cpp(41 KB)
📄 GuardUtils.cpp(3.27 KB)
📄 HeatUtils.cpp(2.85 KB)
📄 IVDescriptors.cpp(42.28 KB)
📄 IVUsers.cpp(16.12 KB)
📄 IndirectCallPromotionAnalysis.cpp(4.33 KB)
📄 InlineAdvisor.cpp(15.28 KB)
📄 InlineCost.cpp(99.47 KB)
📄 InlineFeaturesAnalysis.cpp(1.59 KB)
📄 InlineSizeEstimatorAnalysis.cpp(10.95 KB)
📄 InstCount.cpp(2.45 KB)
📄 InstructionPrecedenceTracking.cpp(4.8 KB)
📄 InstructionSimplify.cpp(216.91 KB)
📄 Interval.cpp(1.78 KB)
📄 IntervalPartition.cpp(4.5 KB)
📄 LazyBlockFrequencyInfo.cpp(2.81 KB)
📄 LazyBranchProbabilityInfo.cpp(2.96 KB)
📄 LazyCallGraph.cpp(67.33 KB)
📄 LazyValueInfo.cpp(76.38 KB)
📄 LegacyDivergenceAnalysis.cpp(14.82 KB)
📄 Lint.cpp(29.07 KB)
📄 Loads.cpp(20.6 KB)
📄 LoopAccessAnalysis.cpp(88.02 KB)
📄 LoopAnalysisManager.cpp(6.6 KB)
📄 LoopCacheAnalysis.cpp(23.53 KB)
📄 LoopInfo.cpp(37.15 KB)
📄 LoopNestAnalysis.cpp(10.62 KB)
📄 LoopPass.cpp(12.89 KB)
📄 LoopUnrollAnalyzer.cpp(7.26 KB)
📄 MLInlineAdvisor.cpp(11.36 KB)
📄 MemDepPrinter.cpp(5.13 KB)
📄 MemDerefPrinter.cpp(2.53 KB)
📄 MemoryBuiltins.cpp(41.14 KB)
📄 MemoryDependenceAnalysis.cpp(69.89 KB)
📄 MemoryLocation.cpp(7.92 KB)
📄 MemorySSA.cpp(90.16 KB)
📄 MemorySSAUpdater.cpp(57.9 KB)
📄 ModuleDebugInfoPrinter.cpp(4.02 KB)
📄 ModuleSummaryAnalysis.cpp(38.13 KB)
📄 MustExecute.cpp(31.18 KB)
📄 ObjCARCAliasAnalysis.cpp(5.81 KB)
📄 ObjCARCAnalysisUtils.cpp(1.07 KB)
📄 ObjCARCInstKind.cpp(23.15 KB)
📄 OptimizationRemarkEmitter.cpp(4.23 KB)
📄 PHITransAddr.cpp(16.05 KB)
📄 PhiValues.cpp(8.4 KB)
📄 PostDominators.cpp(3.59 KB)
📄 ProfileSummaryInfo.cpp(18.07 KB)
📄 PtrUseVisitor.cpp(1.28 KB)
📄 RegionInfo.cpp(6.5 KB)
📄 RegionPass.cpp(9.23 KB)
📄 RegionPrinter.cpp(8.61 KB)
📄 ReleaseModeModelRunner.cpp(2.83 KB)
📄 ScalarEvolution.cpp(475.26 KB)
📄 ScalarEvolutionAliasAnalysis.cpp(5.96 KB)
📄 ScalarEvolutionDivision.cpp(7.51 KB)
📄 ScalarEvolutionNormalization.cpp(4.59 KB)
📄 ScopedNoAliasAA.cpp(7.38 KB)
📄 StackLifetime.cpp(12.22 KB)
📄 StackSafetyAnalysis.cpp(31.81 KB)
📄 StratifiedSets.h(18.67 KB)
📄 SyncDependenceAnalysis.cpp(12.97 KB)
📄 SyntheticCountsUtils.cpp(3.81 KB)
📄 TFUtils.cpp(8.99 KB)
📄 TargetLibraryInfo.cpp(58.98 KB)
📄 TargetTransformInfo.cpp(48.15 KB)
📄 Trace.cpp(1.8 KB)
📄 TypeBasedAliasAnalysis.cpp(26.04 KB)
📄 TypeMetadataUtils.cpp(5.93 KB)
📄 VFABIDemangling.cpp(16.46 KB)
📄 ValueLattice.cpp(1.19 KB)
📄 ValueLatticeUtils.cpp(1.53 KB)
📄 ValueTracking.cpp(243.08 KB)
📄 VectorUtils.cpp(48.57 KB)
📁 models

Editing: LoopUnrollAnalyzer.cpp

//===- LoopUnrollAnalyzer.cpp - Unrolling Effect Estimation -----*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements UnrolledInstAnalyzer class. It's used for predicting
// potential effects that loop unrolling might have, such as enabling constant
// propagation and other optimizations.
//
//===----------------------------------------------------------------------===//

#include "llvm/Analysis/LoopUnrollAnalyzer.h"
#include "llvm/Analysis/LoopInfo.h"

using namespace llvm;

/// Try to simplify instruction \param I using its SCEV expression.
///
/// The idea is that some AddRec expressions become constants, which then
/// could trigger folding of other instructions. However, that only happens
/// for expressions whose start value is also constant, which isn't always the
/// case. In another common and important case the start value is just some
/// address (i.e. SCEVUnknown) - in this case we compute the offset and save
/// it along with the base address instead.
bool UnrolledInstAnalyzer::simplifyInstWithSCEV(Instruction *I) {
  if (!SE.isSCEVable(I->getType()))
    return false;

const SCEV *S = SE.getSCEV(I);
  if (auto *SC = dyn_cast<SCEVConstant>(S)) {
    SimplifiedValues[I] = SC->getValue();
    return true;
  }

auto *AR = dyn_cast<SCEVAddRecExpr>(S);
  if (!AR || AR->getLoop() != L)
    return false;

const SCEV *ValueAtIteration = AR->evaluateAtIteration(IterationNumber, SE);
  // Check if the AddRec expression becomes a constant.
  if (auto *SC = dyn_cast<SCEVConstant>(ValueAtIteration)) {
    SimplifiedValues[I] = SC->getValue();
    return true;
  }

// Check if the offset from the base address becomes a constant.
  auto *Base = dyn_cast<SCEVUnknown>(SE.getPointerBase(S));
  if (!Base)
    return false;
  auto *Offset =
      dyn_cast<SCEVConstant>(SE.getMinusSCEV(ValueAtIteration, Base));
  if (!Offset)
    return false;
  SimplifiedAddress Address;
  Address.Base = Base->getValue();
  Address.Offset = Offset->getValue();
  SimplifiedAddresses[I] = Address;
  return false;
}

/// Try to simplify binary operator I.
///
/// TODO: Probably it's worth to hoist the code for estimating the
/// simplifications effects to a separate class, since we have a very similar
/// code in InlineCost already.
bool UnrolledInstAnalyzer::visitBinaryOperator(BinaryOperator &I) {
  Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
  if (!isa<Constant>(LHS))
    if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS))
      LHS = SimpleLHS;
  if (!isa<Constant>(RHS))
    if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS))
      RHS = SimpleRHS;

Value *SimpleV = nullptr;
  const DataLayout &DL = I.getModule()->getDataLayout();
  if (auto FI = dyn_cast<FPMathOperator>(&I))
    SimpleV =
        SimplifyBinOp(I.getOpcode(), LHS, RHS, FI->getFastMathFlags(), DL);
  else
    SimpleV = SimplifyBinOp(I.getOpcode(), LHS, RHS, DL);

if (Constant *C = dyn_cast_or_null<Constant>(SimpleV))
    SimplifiedValues[&I] = C;

if (SimpleV)
    return true;
  return Base::visitBinaryOperator(I);
}

/// Try to fold load I.
bool UnrolledInstAnalyzer::visitLoad(LoadInst &I) {
  Value *AddrOp = I.getPointerOperand();

auto AddressIt = SimplifiedAddresses.find(AddrOp);
  if (AddressIt == SimplifiedAddresses.end())
    return false;
  ConstantInt *SimplifiedAddrOp = AddressIt->second.Offset;

auto *GV = dyn_cast<GlobalVariable>(AddressIt->second.Base);
  // We're only interested in loads that can be completely folded to a
  // constant.
  if (!GV || !GV->hasDefinitiveInitializer() || !GV->isConstant())
    return false;

ConstantDataSequential *CDS =
      dyn_cast<ConstantDataSequential>(GV->getInitializer());
  if (!CDS)
    return false;

// We might have a vector load from an array. FIXME: for now we just bail
  // out in this case, but we should be able to resolve and simplify such
  // loads.
  if (CDS->getElementType() != I.getType())
    return false;

unsigned ElemSize = CDS->getElementType()->getPrimitiveSizeInBits() / 8U;
  if (SimplifiedAddrOp->getValue().getActiveBits() > 64)
    return false;
  int64_t SimplifiedAddrOpV = SimplifiedAddrOp->getSExtValue();
  if (SimplifiedAddrOpV < 0) {
    // FIXME: For now we conservatively ignore out of bound accesses, but
    // we're allowed to perform the optimization in this case.
    return false;
  }
  uint64_t Index = static_cast<uint64_t>(SimplifiedAddrOpV) / ElemSize;
  if (Index >= CDS->getNumElements()) {
    // FIXME: For now we conservatively ignore out of bound accesses, but
    // we're allowed to perform the optimization in this case.
    return false;
  }

Constant *CV = CDS->getElementAsConstant(Index);
  assert(CV && "Constant expected.");
  SimplifiedValues[&I] = CV;

return true;
}

/// Try to simplify cast instruction.
bool UnrolledInstAnalyzer::visitCastInst(CastInst &I) {
  // Propagate constants through casts.
  Constant *COp = dyn_cast<Constant>(I.getOperand(0));
  if (!COp)
    COp = SimplifiedValues.lookup(I.getOperand(0));

// If we know a simplified value for this operand and cast is valid, save the
  // result to SimplifiedValues.
  // The cast can be invalid, because SimplifiedValues contains results of SCEV
  // analysis, which operates on integers (and, e.g., might convert i8* null to
  // i32 0).
  if (COp && CastInst::castIsValid(I.getOpcode(), COp, I.getType())) {
    if (Constant *C =
            ConstantExpr::getCast(I.getOpcode(), COp, I.getType())) {
      SimplifiedValues[&I] = C;
      return true;
    }
  }

return Base::visitCastInst(I);
}

/// Try to simplify cmp instruction.
bool UnrolledInstAnalyzer::visitCmpInst(CmpInst &I) {
  Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);

// First try to handle simplified comparisons.
  if (!isa<Constant>(LHS))
    if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS))
      LHS = SimpleLHS;
  if (!isa<Constant>(RHS))
    if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS))
      RHS = SimpleRHS;

if (!isa<Constant>(LHS) && !isa<Constant>(RHS)) {
    auto SimplifiedLHS = SimplifiedAddresses.find(LHS);
    if (SimplifiedLHS != SimplifiedAddresses.end()) {
      auto SimplifiedRHS = SimplifiedAddresses.find(RHS);
      if (SimplifiedRHS != SimplifiedAddresses.end()) {
        SimplifiedAddress &LHSAddr = SimplifiedLHS->second;
        SimplifiedAddress &RHSAddr = SimplifiedRHS->second;
        if (LHSAddr.Base == RHSAddr.Base) {
          LHS = LHSAddr.Offset;
          RHS = RHSAddr.Offset;
        }
      }
    }
  }

if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
    if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
      if (CLHS->getType() == CRHS->getType()) {
        if (Constant *C = ConstantExpr::getCompare(I.getPredicate(), CLHS, CRHS)) {
          SimplifiedValues[&I] = C;
          return true;
        }
      }
    }
  }

return Base::visitCmpInst(I);
}

bool UnrolledInstAnalyzer::visitPHINode(PHINode &PN) {
  // Run base visitor first. This way we can gather some useful for later
  // analysis information.
  if (Base::visitPHINode(PN))
    return true;

// The loop induction PHI nodes are definitionally free.
  return PN.getParent() == L->getHeader();
}

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Editing: LoopUnrollAnalyzer.cpp

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