X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FBlockFrequencyInfoImpl.cpp;h=278073cd6c52d433c684d882190ad3ef3f2d5052;hb=92602ea18e3d3b1fb6b780a2aa0301004f2c7285;hp=d8e633c47cef573a819510dbfa5c3a26475fa2ca;hpb=6ecab5a5b18a38512f685c059017ad6464643b96;p=oota-llvm.git diff --git a/lib/Analysis/BlockFrequencyInfoImpl.cpp b/lib/Analysis/BlockFrequencyInfoImpl.cpp index d8e633c47ce..278073cd6c5 100644 --- a/lib/Analysis/BlockFrequencyInfoImpl.cpp +++ b/lib/Analysis/BlockFrequencyInfoImpl.cpp @@ -12,210 +12,15 @@ //===----------------------------------------------------------------------===// #include "llvm/Analysis/BlockFrequencyInfoImpl.h" -#include "llvm/ADT/APFloat.h" #include "llvm/ADT/SCCIterator.h" #include "llvm/Support/raw_ostream.h" -#include +#include using namespace llvm; using namespace llvm::bfi_detail; #define DEBUG_TYPE "block-freq" -//===----------------------------------------------------------------------===// -// -// ScaledNumber implementation. -// -//===----------------------------------------------------------------------===// -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 >= ScaledNumbers::MinScale); - assert(E <= ScaledNumbers::MaxScale); - - // Find a new E, but don't let it increase past MaxScale. - int LeadingZeros = ScaledNumberBase::countLeadingZeros64(D); - int NewE = std::min(ScaledNumbers::MaxScale, E + 63 - LeadingZeros); - int Shift = 63 - (NewE - E); - assert(Shift <= LeadingZeros); - assert(Shift == LeadingZeros || NewE == ScaledNumbers::MaxScale); - D <<= Shift; - E = NewE; - - // Check for a denormal. - unsigned AdjustedE = E + 16383; - if (!(D >> 63)) { - assert(E == ScaledNumbers::MaxScale); - 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 ScaledNumberBase::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 &ScaledNumberBase::print(raw_ostream &OS, uint64_t D, int16_t E, - int Width, unsigned Precision) { - return OS << toString(D, E, Width, Precision); -} - -void ScaledNumberBase::dump(uint64_t D, int16_t E, int Width) { - print(dbgs(), D, E, Width, 0) << "[" << Width << ":" << D << "*2^" << E - << "]"; -} - -//===----------------------------------------------------------------------===// -// -// BlockMass implementation. -// -//===----------------------------------------------------------------------===// ScaledNumber BlockMass::toScaled() const { if (isFull()) return ScaledNumber(1, 0); @@ -236,11 +41,6 @@ raw_ostream &BlockMass::print(raw_ostream &OS) const { return OS; } -//===----------------------------------------------------------------------===// -// -// BlockFrequencyInfoImpl implementation. -// -//===----------------------------------------------------------------------===// namespace { typedef BlockFrequencyInfoImplBase::BlockNode BlockNode; @@ -277,7 +77,8 @@ struct DitheringDistributer { BlockMass takeMass(uint32_t Weight); }; -} + +} // end namespace DitheringDistributer::DitheringDistributer(Distribution &Dist, const BlockMass &Mass) { @@ -311,11 +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) { @@ -326,8 +123,12 @@ static void combineWeight(Weight &W, const Weight &OtherW) { } assert(W.Type == OtherW.Type); assert(W.TargetNode == OtherW.TargetNode); - assert(W.Amount < W.Amount + OtherW.Amount && "Unexpected overflow"); - W.Amount += OtherW.Amount; + assert(OtherW.Amount && "Expected non-zero weight"); + if (W.Amount > W.Amount + OtherW.Amount) + // Saturate on overflow. + W.Amount = UINT64_MAX; + else + W.Amount += OtherW.Amount; } static void combineWeightsBySorting(WeightList &Weights) { // Sort so edges to the same node are adjacent. @@ -410,11 +211,19 @@ void Distribution::normalize() { Shift = 33 - countLeadingZeros(Total); // Early exit if nothing needs to be scaled. - if (!Shift) + if (!Shift) { + // If we didn't overflow then combineWeights() shouldn't have changed the + // sum of the weights, but let's double-check. + assert(Total == std::accumulate(Weights.begin(), Weights.end(), UINT64_C(0), + [](uint64_t Sum, const Weight &W) { + return Sum + W.Amount; + }) && + "Expected total to be correct"); return; + } // Recompute the total through accumulation (rather than shifting it) so that - // it's accurate after shifting. + // it's accurate after shifting and any changes combineWeights() made above. Total = 0; // Sum the weights to each node and shift right if necessary. @@ -805,7 +614,8 @@ static void findIrreducibleHeaders( break; } } - assert(Headers.size() >= 2 && "Should be irreducible"); + assert(Headers.size() >= 2 && + "Expected irreducible CFG; -loop-info is likely invalid"); if (Headers.size() == InSCC.size()) { // Every block is a header. std::sort(Headers.begin(), Headers.end());