X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FBlockFrequencyInfoImpl.cpp;h=3203c371648d79822a56e192cc3572f85ef8469d;hb=594e4a1dd36fb69e1420c643b0f548c2bb79c76c;hp=744bbe2fe956a6524a4d6192b3cab43f4fb0c90c;hpb=39087bfbf0b33995b337b676e3c715b3e31a6c1a;p=oota-llvm.git diff --git a/lib/Analysis/BlockFrequencyInfoImpl.cpp b/lib/Analysis/BlockFrequencyInfoImpl.cpp index 744bbe2fe95..3203c371648 100644 --- a/lib/Analysis/BlockFrequencyInfoImpl.cpp +++ b/lib/Analysis/BlockFrequencyInfoImpl.cpp @@ -12,334 +12,19 @@ //===----------------------------------------------------------------------===// #include "llvm/Analysis/BlockFrequencyInfoImpl.h" -#include "llvm/ADT/APFloat.h" +#include "llvm/ADT/SCCIterator.h" #include "llvm/Support/raw_ostream.h" #include using namespace llvm; +using namespace llvm::bfi_detail; #define DEBUG_TYPE "block-freq" -//===----------------------------------------------------------------------===// -// -// UnsignedFloat implementation. -// -//===----------------------------------------------------------------------===// -#ifndef _MSC_VER -const int32_t UnsignedFloatBase::MaxExponent; -const int32_t UnsignedFloatBase::MinExponent; -#endif - -static void appendDigit(std::string &Str, unsigned D) { - assert(D < 10); - Str += '0' + D % 10; -} - -static void appendNumber(std::string &Str, uint64_t N) { - while (N) { - appendDigit(Str, N % 10); - N /= 10; - } -} - -static bool doesRoundUp(char Digit) { - switch (Digit) { - case '5': - case '6': - case '7': - case '8': - case '9': - return true; - default: - return false; - } -} - -static std::string toStringAPFloat(uint64_t D, int E, unsigned Precision) { - assert(E >= UnsignedFloatBase::MinExponent); - assert(E <= UnsignedFloatBase::MaxExponent); - - // Find a new E, but don't let it increase past MaxExponent. - int LeadingZeros = UnsignedFloatBase::countLeadingZeros64(D); - int NewE = std::min(UnsignedFloatBase::MaxExponent, E + 63 - LeadingZeros); - int Shift = 63 - (NewE - E); - assert(Shift <= LeadingZeros); - assert(Shift == LeadingZeros || NewE == UnsignedFloatBase::MaxExponent); - D <<= Shift; - E = NewE; - - // Check for a denormal. - unsigned AdjustedE = E + 16383; - if (!(D >> 63)) { - assert(E == UnsignedFloatBase::MaxExponent); - AdjustedE = 0; - } - - // Build the float and print it. - uint64_t RawBits[2] = {D, AdjustedE}; - APFloat Float(APFloat::x87DoubleExtended, APInt(80, RawBits)); - SmallVector Chars; - Float.toString(Chars, Precision, 0); - return std::string(Chars.begin(), Chars.end()); -} - -static std::string stripTrailingZeros(const std::string &Float) { - size_t NonZero = Float.find_last_not_of('0'); - assert(NonZero != std::string::npos && "no . in floating point string"); - - if (Float[NonZero] == '.') - ++NonZero; - - return Float.substr(0, NonZero + 1); -} - -std::string UnsignedFloatBase::toString(uint64_t D, int16_t E, int Width, - unsigned Precision) { - if (!D) - return "0.0"; - - // Canonicalize exponent and digits. - uint64_t Above0 = 0; - uint64_t Below0 = 0; - uint64_t Extra = 0; - int ExtraShift = 0; - if (E == 0) { - Above0 = D; - } else if (E > 0) { - if (int Shift = std::min(int16_t(countLeadingZeros64(D)), E)) { - D <<= Shift; - E -= Shift; - - if (!E) - Above0 = D; - } - } else if (E > -64) { - Above0 = D >> -E; - Below0 = D << (64 + E); - } else if (E > -120) { - Below0 = D >> (-E - 64); - Extra = D << (128 + E); - ExtraShift = -64 - E; - } - - // Fall back on APFloat for very small and very large numbers. - if (!Above0 && !Below0) - return toStringAPFloat(D, E, Precision); - - // Append the digits before the decimal. - std::string Str; - size_t DigitsOut = 0; - if (Above0) { - appendNumber(Str, Above0); - DigitsOut = Str.size(); - } else - appendDigit(Str, 0); - std::reverse(Str.begin(), Str.end()); - - // Return early if there's nothing after the decimal. - if (!Below0) - return Str + ".0"; - - // Append the decimal and beyond. - Str += '.'; - uint64_t Error = UINT64_C(1) << (64 - Width); - - // We need to shift Below0 to the right to make space for calculating - // digits. Save the precision we're losing in Extra. - Extra = (Below0 & 0xf) << 56 | (Extra >> 8); - Below0 >>= 4; - size_t SinceDot = 0; - size_t AfterDot = Str.size(); - do { - if (ExtraShift) { - --ExtraShift; - Error *= 5; - } else - Error *= 10; - - Below0 *= 10; - Extra *= 10; - Below0 += (Extra >> 60); - Extra = Extra & (UINT64_MAX >> 4); - appendDigit(Str, Below0 >> 60); - Below0 = Below0 & (UINT64_MAX >> 4); - if (DigitsOut || Str.back() != '0') - ++DigitsOut; - ++SinceDot; - } while (Error && (Below0 << 4 | Extra >> 60) >= Error / 2 && - (!Precision || DigitsOut <= Precision || SinceDot < 2)); - - // Return early for maximum precision. - if (!Precision || DigitsOut <= Precision) - return stripTrailingZeros(Str); - - // Find where to truncate. - size_t Truncate = - std::max(Str.size() - (DigitsOut - Precision), AfterDot + 1); - - // Check if there's anything to truncate. - if (Truncate >= Str.size()) - return stripTrailingZeros(Str); - - bool Carry = doesRoundUp(Str[Truncate]); - if (!Carry) - return stripTrailingZeros(Str.substr(0, Truncate)); - - // Round with the first truncated digit. - for (std::string::reverse_iterator I(Str.begin() + Truncate), E = Str.rend(); - I != E; ++I) { - if (*I == '.') - continue; - if (*I == '9') { - *I = '0'; - continue; - } - - ++*I; - Carry = false; - break; - } - - // Add "1" in front if we still need to carry. - return stripTrailingZeros(std::string(Carry, '1') + Str.substr(0, Truncate)); -} - -raw_ostream &UnsignedFloatBase::print(raw_ostream &OS, uint64_t D, int16_t E, - int Width, unsigned Precision) { - return OS << toString(D, E, Width, Precision); -} - -void UnsignedFloatBase::dump(uint64_t D, int16_t E, int Width) { - print(dbgs(), D, E, Width, 0) << "[" << Width << ":" << D << "*2^" << E - << "]"; -} - -static std::pair -getRoundedFloat(uint64_t N, bool ShouldRound, int64_t Shift) { - if (ShouldRound) - if (!++N) - // Rounding caused an overflow. - return std::make_pair(UINT64_C(1), Shift + 64); - return std::make_pair(N, Shift); -} - -std::pair UnsignedFloatBase::divide64(uint64_t Dividend, - uint64_t Divisor) { - // Input should be sanitized. - assert(Divisor); - assert(Dividend); - - // Minimize size of divisor. - int16_t Shift = 0; - if (int Zeros = countTrailingZeros(Divisor)) { - Shift -= Zeros; - Divisor >>= Zeros; - } - - // Check for powers of two. - if (Divisor == 1) - return std::make_pair(Dividend, Shift); - - // Maximize size of dividend. - if (int Zeros = countLeadingZeros64(Dividend)) { - Shift -= Zeros; - Dividend <<= Zeros; - } - - // Start with the result of a divide. - uint64_t Quotient = Dividend / Divisor; - Dividend %= Divisor; - - // Continue building the quotient with long division. - // - // TODO: continue with largers digits. - while (!(Quotient >> 63) && Dividend) { - // Shift Dividend, and check for overflow. - bool IsOverflow = Dividend >> 63; - Dividend <<= 1; - --Shift; - - // Divide. - bool DoesDivide = IsOverflow || Divisor <= Dividend; - Quotient = (Quotient << 1) | uint64_t(DoesDivide); - Dividend -= DoesDivide ? Divisor : 0; - } - - // Round. - if (Dividend >= getHalf(Divisor)) - if (!++Quotient) - // Rounding caused an overflow in Quotient. - return std::make_pair(UINT64_C(1), Shift + 64); - - return getRoundedFloat(Quotient, Dividend >= getHalf(Divisor), Shift); -} - -std::pair UnsignedFloatBase::multiply64(uint64_t L, - uint64_t R) { - // Separate into two 32-bit digits (U.L). - uint64_t UL = L >> 32, LL = L & UINT32_MAX, UR = R >> 32, LR = R & UINT32_MAX; - - // Compute cross products. - uint64_t P1 = UL * UR, P2 = UL * LR, P3 = LL * UR, P4 = LL * LR; - - // Sum into two 64-bit digits. - uint64_t Upper = P1, Lower = P4; - auto addWithCarry = [&](uint64_t N) { - uint64_t NewLower = Lower + (N << 32); - Upper += (N >> 32) + (NewLower < Lower); - Lower = NewLower; - }; - addWithCarry(P2); - addWithCarry(P3); - - // Check whether the upper digit is empty. - if (!Upper) - return std::make_pair(Lower, 0); - - // Shift as little as possible to maximize precision. - unsigned LeadingZeros = countLeadingZeros64(Upper); - int16_t Shift = 64 - LeadingZeros; - if (LeadingZeros) - Upper = Upper << LeadingZeros | Lower >> Shift; - bool ShouldRound = Shift && (Lower & UINT64_C(1) << (Shift - 1)); - return getRoundedFloat(Upper, ShouldRound, Shift); -} - -//===----------------------------------------------------------------------===// -// -// BlockMass implementation. -// -//===----------------------------------------------------------------------===// -BlockMass &BlockMass::operator*=(const BranchProbability &P) { - uint32_t N = P.getNumerator(), D = P.getDenominator(); - assert(D && "divide by 0"); - assert(N <= D && "fraction greater than 1"); - - // Fast path for multiplying by 1.0. - if (!Mass || N == D) - return *this; - - // Get as much precision as we can. - int Shift = countLeadingZeros(Mass); - uint64_t ShiftedQuotient = (Mass << Shift) / D; - uint64_t Product = ShiftedQuotient * N >> Shift; - - // Now check for what's lost. - uint64_t Left = ShiftedQuotient * (D - N) >> Shift; - uint64_t Lost = Mass - Product - Left; - - // TODO: prove this assertion. - assert(Lost <= UINT32_MAX); - - // Take the product plus a portion of the spoils. - Mass = Product + Lost * N / D; - return *this; -} - -UnsignedFloat BlockMass::toFloat() const { +ScaledNumber BlockMass::toScaled() const { if (isFull()) - return UnsignedFloat(1, 0); - return UnsignedFloat(getMass() + 1, -64); + return ScaledNumber(1, 0); + return ScaledNumber(getMass() + 1, -64); } void BlockMass::dump() const { print(dbgs()); } @@ -356,17 +41,12 @@ raw_ostream &BlockMass::print(raw_ostream &OS) const { return OS; } -//===----------------------------------------------------------------------===// -// -// BlockFrequencyInfoImpl implementation. -// -//===----------------------------------------------------------------------===// namespace { typedef BlockFrequencyInfoImplBase::BlockNode BlockNode; typedef BlockFrequencyInfoImplBase::Distribution Distribution; typedef BlockFrequencyInfoImplBase::Distribution::WeightList WeightList; -typedef BlockFrequencyInfoImplBase::Float Float; +typedef BlockFrequencyInfoImplBase::Scaled64 Scaled64; typedef BlockFrequencyInfoImplBase::LoopData LoopData; typedef BlockFrequencyInfoImplBase::Weight Weight; typedef BlockFrequencyInfoImplBase::FrequencyData FrequencyData; @@ -397,7 +77,8 @@ struct DitheringDistributer { BlockMass takeMass(uint32_t Weight); }; -} + +} // end namespace DitheringDistributer::DitheringDistributer(Distribution &Dist, const BlockMass &Mass) { @@ -431,11 +112,7 @@ void Distribution::add(const BlockNode &Node, uint64_t Amount, Total = NewTotal; // Save the weight. - Weight W; - W.TargetNode = Node; - W.Amount = Amount; - W.Type = Type; - Weights.push_back(W); + Weights.push_back(Weight(Type, Node, Amount)); } static void combineWeight(Weight &W, const Weight &OtherW) { @@ -568,22 +245,7 @@ static void cleanup(BlockFrequencyInfoImplBase &BFI) { BFI.Freqs = std::move(SavedFreqs); } -/// \brief Get the appropriate mass for a possible pseudo-node loop package. -/// -/// Get appropriate mass for Node. If Node is a loop-header (whose loop has -/// been packaged), returns the mass of its pseudo-node. If it's a node inside -/// a packaged loop, it returns the loop's pseudo-node. -static BlockMass &getPackageMass(BlockFrequencyInfoImplBase &BFI, - const BlockNode &Node) { - assert(Node.isValid()); - assert(!BFI.Working[Node.Index].isPackaged()); - if (!BFI.Working[Node.Index].isAPackage()) - return BFI.Working[Node.Index].Mass; - - return BFI.getLoopPackage(Node).Mass; -} - -void BlockFrequencyInfoImplBase::addToDist(Distribution &Dist, +bool BlockFrequencyInfoImplBase::addToDist(Distribution &Dist, const LoopData *OuterLoop, const BlockNode &Pred, const BlockNode &Succ, @@ -595,11 +257,13 @@ void BlockFrequencyInfoImplBase::addToDist(Distribution &Dist, return OuterLoop && OuterLoop->isHeader(Node); }; + BlockNode Resolved = Working[Succ.Index].getResolvedNode(); + #ifndef NDEBUG - auto debugSuccessor = [&](const char *Type, const BlockNode &Resolved) { + auto debugSuccessor = [&](const char *Type) { dbgs() << " =>" << " [" << Type << "] weight = " << Weight; - if (!isLoopHeader(Succ)) + if (!isLoopHeader(Resolved)) dbgs() << ", succ = " << getBlockName(Succ); if (Resolved != Succ) dbgs() << ", resolved = " << getBlockName(Resolved); @@ -608,59 +272,70 @@ void BlockFrequencyInfoImplBase::addToDist(Distribution &Dist, (void)debugSuccessor; #endif - if (isLoopHeader(Succ)) { - DEBUG(debugSuccessor("backedge", Succ)); + if (isLoopHeader(Resolved)) { + DEBUG(debugSuccessor("backedge")); Dist.addBackedge(OuterLoop->getHeader(), Weight); - return; + return true; } - BlockNode Resolved = getPackagedNode(Succ); - assert(!isLoopHeader(Resolved)); if (Working[Resolved.Index].getContainingLoop() != OuterLoop) { - DEBUG(debugSuccessor(" exit ", Resolved)); + DEBUG(debugSuccessor(" exit ")); Dist.addExit(Resolved, Weight); - return; + return true; } if (Resolved < Pred) { - // Irreducible backedge. Skip this edge in the distribution. - DEBUG(debugSuccessor("skipped ", Resolved)); - return; + if (!isLoopHeader(Pred)) { + // If OuterLoop is an irreducible loop, we can't actually handle this. + assert((!OuterLoop || !OuterLoop->isIrreducible()) && + "unhandled irreducible control flow"); + + // Irreducible backedge. Abort. + DEBUG(debugSuccessor("abort!!!")); + return false; + } + + // If "Pred" is a loop header, then this isn't really a backedge; rather, + // OuterLoop must be irreducible. These false backedges can come only from + // secondary loop headers. + assert(OuterLoop && OuterLoop->isIrreducible() && !isLoopHeader(Resolved) && + "unhandled irreducible control flow"); } - DEBUG(debugSuccessor(" local ", Resolved)); + DEBUG(debugSuccessor(" local ")); Dist.addLocal(Resolved, Weight); + return true; } -void BlockFrequencyInfoImplBase::addLoopSuccessorsToDist( +bool BlockFrequencyInfoImplBase::addLoopSuccessorsToDist( const LoopData *OuterLoop, LoopData &Loop, Distribution &Dist) { // Copy the exit map into Dist. for (const auto &I : Loop.Exits) - addToDist(Dist, OuterLoop, Loop.getHeader(), I.first, I.second.getMass()); + if (!addToDist(Dist, OuterLoop, Loop.getHeader(), I.first, + I.second.getMass())) + // Irreducible backedge. + return false; - // We don't need this map any more. Clear it to prevent quadratic memory - // usage in deeply nested loops with irreducible control flow. - Loop.Exits.clear(); + return true; } /// \brief Get the maximum allowed loop scale. /// /// Gives the maximum number of estimated iterations allowed for a loop. Very /// large numbers cause problems downstream (even within 64-bits). -static Float getMaxLoopScale() { return Float(1, 12); } +static Scaled64 getMaxLoopScale() { return Scaled64(1, 12); } /// \brief Compute the loop scale for a loop. void BlockFrequencyInfoImplBase::computeLoopScale(LoopData &Loop) { // Compute loop scale. - DEBUG(dbgs() << "compute-loop-scale: " << getBlockName(Loop.getHeader()) - << "\n"); + DEBUG(dbgs() << "compute-loop-scale: " << getLoopName(Loop) << "\n"); // LoopScale == 1 / ExitMass // ExitMass == HeadMass - BackedgeMass BlockMass ExitMass = BlockMass::getFull() - Loop.BackedgeMass; // Block scale stores the inverse of the scale. - Loop.Scale = ExitMass.toFloat().inverse(); + Loop.Scale = ExitMass.toScaled().inverse(); DEBUG(dbgs() << " - exit-mass = " << ExitMass << " (" << BlockMass::getFull() << " - " << Loop.BackedgeMass << ")\n" @@ -674,18 +349,21 @@ void BlockFrequencyInfoImplBase::computeLoopScale(LoopData &Loop) { /// \brief Package up a loop. void BlockFrequencyInfoImplBase::packageLoop(LoopData &Loop) { - DEBUG(dbgs() << "packaging-loop: " << getBlockName(Loop.getHeader()) << "\n"); + DEBUG(dbgs() << "packaging-loop: " << getLoopName(Loop) << "\n"); + + // Clear the subloop exits to prevent quadratic memory usage. + for (const BlockNode &M : Loop.Nodes) { + if (auto *Loop = Working[M.Index].getPackagedLoop()) + Loop->Exits.clear(); + DEBUG(dbgs() << " - node: " << getBlockName(M.Index) << "\n"); + } Loop.IsPackaged = true; - DEBUG(for (const BlockNode &M - : Loop.members()) { - dbgs() << " - node: " << getBlockName(M.Index) << "\n"; - }); } void BlockFrequencyInfoImplBase::distributeMass(const BlockNode &Source, LoopData *OuterLoop, Distribution &Dist) { - BlockMass Mass = getPackageMass(*this, Source); + BlockMass Mass = Working[Source.Index].getMass(); DEBUG(dbgs() << " => mass: " << Mass << "\n"); // Distribute mass to successors as laid out in Dist. @@ -708,7 +386,7 @@ void BlockFrequencyInfoImplBase::distributeMass(const BlockNode &Source, // Check for a local edge (non-backedge and non-exit). BlockMass Taken = D.takeMass(W.Amount); if (W.Type == Weight::Local) { - getPackageMass(*this, W.TargetNode) += Taken; + Working[W.TargetNode.Index].getMass() += Taken; DEBUG(debugAssign(W.TargetNode, Taken, nullptr)); continue; } @@ -731,15 +409,16 @@ void BlockFrequencyInfoImplBase::distributeMass(const BlockNode &Source, } static void convertFloatingToInteger(BlockFrequencyInfoImplBase &BFI, - const Float &Min, const Float &Max) { + const Scaled64 &Min, const Scaled64 &Max) { // Scale the Factor to a size that creates integers. Ideally, integers would // be scaled so that Max == UINT64_MAX so that they can be best // differentiated. However, the register allocator currently deals poorly // with large numbers. Instead, push Min up a little from 1 to give some // room to differentiate small, unequal numbers. // - // TODO: fix issues downstream so that ScalingFactor can be Float(1,64)/Max. - Float ScalingFactor = Min.inverse(); + // TODO: fix issues downstream so that ScalingFactor can be + // Scaled64(1,64)/Max. + Scaled64 ScalingFactor = Min.inverse(); if ((Max / Min).lg() < 60) ScalingFactor <<= 3; @@ -747,10 +426,10 @@ static void convertFloatingToInteger(BlockFrequencyInfoImplBase &BFI, DEBUG(dbgs() << "float-to-int: min = " << Min << ", max = " << Max << ", factor = " << ScalingFactor << "\n"); for (size_t Index = 0; Index < BFI.Freqs.size(); ++Index) { - Float Scaled = BFI.Freqs[Index].Floating * ScalingFactor; + Scaled64 Scaled = BFI.Freqs[Index].Scaled * ScalingFactor; BFI.Freqs[Index].Integer = std::max(UINT64_C(1), Scaled.toInt()); DEBUG(dbgs() << " - " << BFI.getBlockName(Index) << ": float = " - << BFI.Freqs[Index].Floating << ", scaled = " << Scaled + << BFI.Freqs[Index].Scaled << ", scaled = " << Scaled << ", int = " << BFI.Freqs[Index].Integer << "\n"); } } @@ -760,10 +439,10 @@ static void convertFloatingToInteger(BlockFrequencyInfoImplBase &BFI, /// Visits all the members of a loop, adjusting their BlockData according to /// the loop's pseudo-node. static void unwrapLoop(BlockFrequencyInfoImplBase &BFI, LoopData &Loop) { - DEBUG(dbgs() << "unwrap-loop-package: " << BFI.getBlockName(Loop.getHeader()) + DEBUG(dbgs() << "unwrap-loop-package: " << BFI.getLoopName(Loop) << ": mass = " << Loop.Mass << ", scale = " << Loop.Scale << "\n"); - Loop.Scale *= Loop.Mass.toFloat(); + Loop.Scale *= Loop.Mass.toScaled(); Loop.IsPackaged = false; DEBUG(dbgs() << " => combined-scale = " << Loop.Scale << "\n"); @@ -772,9 +451,9 @@ static void unwrapLoop(BlockFrequencyInfoImplBase &BFI, LoopData &Loop) { // final head scale will be used for updated the rest of the members. for (const BlockNode &N : Loop.Nodes) { const auto &Working = BFI.Working[N.Index]; - Float &F = Working.isAPackage() ? BFI.getLoopPackage(N).Scale - : BFI.Freqs[N.Index].Floating; - Float New = Loop.Scale * F; + Scaled64 &F = Working.isAPackage() ? Working.getPackagedLoop()->Scale + : BFI.Freqs[N.Index].Scaled; + Scaled64 New = Loop.Scale * F; DEBUG(dbgs() << " - " << BFI.getBlockName(N) << ": " << F << " => " << New << "\n"); F = New; @@ -784,7 +463,7 @@ static void unwrapLoop(BlockFrequencyInfoImplBase &BFI, LoopData &Loop) { void BlockFrequencyInfoImplBase::unwrapLoops() { // Set initial frequencies from loop-local masses. for (size_t Index = 0; Index < Working.size(); ++Index) - Freqs[Index].Floating = Working[Index].Mass.toFloat(); + Freqs[Index].Scaled = Working[Index].Mass.toScaled(); for (LoopData &Loop : Loops) unwrapLoop(*this, Loop); @@ -793,12 +472,12 @@ void BlockFrequencyInfoImplBase::unwrapLoops() { void BlockFrequencyInfoImplBase::finalizeMetrics() { // Unwrap loop packages in reverse post-order, tracking min and max // frequencies. - auto Min = Float::getLargest(); - auto Max = Float::getZero(); + auto Min = Scaled64::getLargest(); + auto Max = Scaled64::getZero(); for (size_t Index = 0; Index < Working.size(); ++Index) { // Update min/max scale. - Min = std::min(Min, Freqs[Index].Floating); - Max = std::max(Max, Freqs[Index].Floating); + Min = std::min(Min, Freqs[Index].Scaled); + Max = std::max(Max, Freqs[Index].Scaled); } // Convert to integers. @@ -817,17 +496,21 @@ BlockFrequencyInfoImplBase::getBlockFreq(const BlockNode &Node) const { return 0; return Freqs[Node.Index].Integer; } -Float +Scaled64 BlockFrequencyInfoImplBase::getFloatingBlockFreq(const BlockNode &Node) const { if (!Node.isValid()) - return Float::getZero(); - return Freqs[Node.Index].Floating; + return Scaled64::getZero(); + return Freqs[Node.Index].Scaled; } std::string BlockFrequencyInfoImplBase::getBlockName(const BlockNode &Node) const { return std::string(); } +std::string +BlockFrequencyInfoImplBase::getLoopName(const LoopData &Loop) const { + return getBlockName(Loop.getHeader()) + (Loop.isIrreducible() ? "**" : "*"); +} raw_ostream & BlockFrequencyInfoImplBase::printBlockFreq(raw_ostream &OS, @@ -838,8 +521,177 @@ BlockFrequencyInfoImplBase::printBlockFreq(raw_ostream &OS, raw_ostream & BlockFrequencyInfoImplBase::printBlockFreq(raw_ostream &OS, const BlockFrequency &Freq) const { - Float Block(Freq.getFrequency(), 0); - Float Entry(getEntryFreq(), 0); + Scaled64 Block(Freq.getFrequency(), 0); + Scaled64 Entry(getEntryFreq(), 0); return OS << Block / Entry; } + +void IrreducibleGraph::addNodesInLoop(const BFIBase::LoopData &OuterLoop) { + Start = OuterLoop.getHeader(); + Nodes.reserve(OuterLoop.Nodes.size()); + for (auto N : OuterLoop.Nodes) + addNode(N); + indexNodes(); +} +void IrreducibleGraph::addNodesInFunction() { + Start = 0; + for (uint32_t Index = 0; Index < BFI.Working.size(); ++Index) + if (!BFI.Working[Index].isPackaged()) + addNode(Index); + indexNodes(); +} +void IrreducibleGraph::indexNodes() { + for (auto &I : Nodes) + Lookup[I.Node.Index] = &I; +} +void IrreducibleGraph::addEdge(IrrNode &Irr, const BlockNode &Succ, + const BFIBase::LoopData *OuterLoop) { + if (OuterLoop && OuterLoop->isHeader(Succ)) + return; + auto L = Lookup.find(Succ.Index); + if (L == Lookup.end()) + return; + IrrNode &SuccIrr = *L->second; + Irr.Edges.push_back(&SuccIrr); + SuccIrr.Edges.push_front(&Irr); + ++SuccIrr.NumIn; +} + +namespace llvm { +template <> struct GraphTraits { + typedef bfi_detail::IrreducibleGraph GraphT; + + typedef const GraphT::IrrNode NodeType; + typedef GraphT::IrrNode::iterator ChildIteratorType; + + static const NodeType *getEntryNode(const GraphT &G) { + return G.StartIrr; + } + static ChildIteratorType child_begin(NodeType *N) { return N->succ_begin(); } + static ChildIteratorType child_end(NodeType *N) { return N->succ_end(); } +}; +} + +/// \brief Find extra irreducible headers. +/// +/// Find entry blocks and other blocks with backedges, which exist when \c G +/// contains irreducible sub-SCCs. +static void findIrreducibleHeaders( + const BlockFrequencyInfoImplBase &BFI, + const IrreducibleGraph &G, + const std::vector &SCC, + LoopData::NodeList &Headers, LoopData::NodeList &Others) { + // Map from nodes in the SCC to whether it's an entry block. + SmallDenseMap InSCC; + + // InSCC also acts the set of nodes in the graph. Seed it. + for (const auto *I : SCC) + InSCC[I] = false; + + for (auto I = InSCC.begin(), E = InSCC.end(); I != E; ++I) { + auto &Irr = *I->first; + for (const auto *P : make_range(Irr.pred_begin(), Irr.pred_end())) { + if (InSCC.count(P)) + continue; + + // This is an entry block. + I->second = true; + Headers.push_back(Irr.Node); + DEBUG(dbgs() << " => entry = " << BFI.getBlockName(Irr.Node) << "\n"); + break; + } + } + assert(Headers.size() >= 2 && "Should be irreducible"); + if (Headers.size() == InSCC.size()) { + // Every block is a header. + std::sort(Headers.begin(), Headers.end()); + return; + } + + // Look for extra headers from irreducible sub-SCCs. + for (const auto &I : InSCC) { + // Entry blocks are already headers. + if (I.second) + continue; + + auto &Irr = *I.first; + for (const auto *P : make_range(Irr.pred_begin(), Irr.pred_end())) { + // Skip forward edges. + if (P->Node < Irr.Node) + continue; + + // Skip predecessors from entry blocks. These can have inverted + // ordering. + if (InSCC.lookup(P)) + continue; + + // Store the extra header. + Headers.push_back(Irr.Node); + DEBUG(dbgs() << " => extra = " << BFI.getBlockName(Irr.Node) << "\n"); + break; + } + if (Headers.back() == Irr.Node) + // Added this as a header. + continue; + + // This is not a header. + Others.push_back(Irr.Node); + DEBUG(dbgs() << " => other = " << BFI.getBlockName(Irr.Node) << "\n"); + } + std::sort(Headers.begin(), Headers.end()); + std::sort(Others.begin(), Others.end()); +} + +static void createIrreducibleLoop( + BlockFrequencyInfoImplBase &BFI, const IrreducibleGraph &G, + LoopData *OuterLoop, std::list::iterator Insert, + const std::vector &SCC) { + // Translate the SCC into RPO. + DEBUG(dbgs() << " - found-scc\n"); + + LoopData::NodeList Headers; + LoopData::NodeList Others; + findIrreducibleHeaders(BFI, G, SCC, Headers, Others); + + auto Loop = BFI.Loops.emplace(Insert, OuterLoop, Headers.begin(), + Headers.end(), Others.begin(), Others.end()); + + // Update loop hierarchy. + for (const auto &N : Loop->Nodes) + if (BFI.Working[N.Index].isLoopHeader()) + BFI.Working[N.Index].Loop->Parent = &*Loop; + else + BFI.Working[N.Index].Loop = &*Loop; +} + +iterator_range::iterator> +BlockFrequencyInfoImplBase::analyzeIrreducible( + const IrreducibleGraph &G, LoopData *OuterLoop, + std::list::iterator Insert) { + assert((OuterLoop == nullptr) == (Insert == Loops.begin())); + auto Prev = OuterLoop ? std::prev(Insert) : Loops.end(); + + for (auto I = scc_begin(G); !I.isAtEnd(); ++I) { + if (I->size() < 2) + continue; + + // Translate the SCC into RPO. + createIrreducibleLoop(*this, G, OuterLoop, Insert, *I); + } + + if (OuterLoop) + return make_range(std::next(Prev), Insert); + return make_range(Loops.begin(), Insert); +} + +void +BlockFrequencyInfoImplBase::updateLoopWithIrreducible(LoopData &OuterLoop) { + OuterLoop.Exits.clear(); + OuterLoop.BackedgeMass = BlockMass::getEmpty(); + auto O = OuterLoop.Nodes.begin() + 1; + for (auto I = O, E = OuterLoop.Nodes.end(); I != E; ++I) + if (!Working[I->Index].isPackaged()) + *O++ = *I; + OuterLoop.Nodes.erase(O, OuterLoop.Nodes.end()); +}