C++ APInt::isNegative方法代码示例

ConstantRange
ConstantRange::makeGuaranteedNoWrapRegion(Instruction::BinaryOps BinOp,
                                          const ConstantRange &Other,
                                          unsigned NoWrapKind) {
  typedef OverflowingBinaryOperator OBO;

  // Computes the intersection of CR0 and CR1.  It is different from
  // intersectWith in that the ConstantRange returned will only contain elements
  // in both CR0 and CR1 (i.e. SubsetIntersect(X, Y) is a *subset*, proper or
  // not, of both X and Y).
  auto SubsetIntersect =
      [](const ConstantRange &CR0, const ConstantRange &CR1) {
    return CR0.inverse().unionWith(CR1.inverse()).inverse();
  };

  assert(BinOp >= Instruction::BinaryOpsBegin &&
         BinOp < Instruction::BinaryOpsEnd && "Binary operators only!");

  assert((NoWrapKind == OBO::NoSignedWrap ||
          NoWrapKind == OBO::NoUnsignedWrap ||
          NoWrapKind == (OBO::NoUnsignedWrap | OBO::NoSignedWrap)) &&
         "NoWrapKind invalid!");

  unsigned BitWidth = Other.getBitWidth();
  if (BinOp != Instruction::Add)
    // Conservative answer: empty set
    return ConstantRange(BitWidth, false);

  if (auto *C = Other.getSingleElement())
    if (C->isMinValue())
      // Full set: nothing signed / unsigned wraps when added to 0.
      return ConstantRange(BitWidth);

  ConstantRange Result(BitWidth);

  if (NoWrapKind & OBO::NoUnsignedWrap)
    Result =
        SubsetIntersect(Result, ConstantRange(APInt::getNullValue(BitWidth),
                                              -Other.getUnsignedMax()));

  if (NoWrapKind & OBO::NoSignedWrap) {
    APInt SignedMin = Other.getSignedMin();
    APInt SignedMax = Other.getSignedMax();

    if (SignedMax.isStrictlyPositive())
      Result = SubsetIntersect(
          Result,
          ConstantRange(APInt::getSignedMinValue(BitWidth),
                        APInt::getSignedMinValue(BitWidth) - SignedMax));

    if (SignedMin.isNegative())
      Result = SubsetIntersect(
          Result, ConstantRange(APInt::getSignedMinValue(BitWidth) - SignedMin,
                                APInt::getSignedMinValue(BitWidth)));
  }

  return Result;
}

    /** Converts v to mpz_class. Assumes that v is signed */
  inline mpz_class toMpz (const APInt &v)
  {
    // Based on:
    // https://llvm.org/svn/llvm-project/polly/trunk/lib/Support/GICHelper.cpp
    // return v.getSExtValue ();

    APInt abs;
    abs = v.isNegative () ? v.abs () : v;
    
    const uint64_t *rawdata = abs.getRawData ();
    unsigned numWords = abs.getNumWords ();

    // TODO: Check if this is true for all platforms.
    mpz_class res;
    mpz_import(res.get_mpz_t (), numWords, 1, sizeof (uint64_t), 0, 0, rawdata);

    return v.isNegative () ? mpz_class(-res) : res;
  }

/// lowerSDIV - Given an SDiv expressing a divide by constant,
/// replace it by multiplying by a magic number.  See:
/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
bool lowerSDiv(Instruction *inst) const {
  ConstantInt *Op1 = dyn_cast<ConstantInt>(inst->getOperand(1));
  // check if dividing by a constant and not by a power of 2
  if (!Op1 || inst->getType()->getPrimitiveSizeInBits() != 32 ||
          Op1->getValue().isPowerOf2()) {
      return false;
  }

  BasicBlock::iterator ii(inst);
  Value *Op0 = inst->getOperand(0);
  APInt d = Op1->getValue();

  APInt::ms magics = Op1->getValue().magic();

  IntegerType * type64 = IntegerType::get(Mod->getContext(), 64);

  Instruction *sext = CastInst::CreateSExtOrBitCast(Op0, type64, "", inst);
  APInt m = APInt(64, magics.m.getSExtValue());
  Constant *magicNum = ConstantInt::get(type64, m);

  Instruction *magInst = BinaryOperator::CreateNSWMul(sext, magicNum, "", inst);

  APInt ap = APInt(64, 32);
  Constant *movHiConst = ConstantInt::get(type64, ap);
  Instruction *movHi = BinaryOperator::Create(Instruction::AShr, magInst, 
    movHiConst, "", inst);
  Instruction *trunc = CastInst::CreateTruncOrBitCast(movHi, inst->getType(),
    "", inst);
  if (d.isStrictlyPositive() && magics.m.isNegative()) {
    trunc = BinaryOperator::Create(Instruction::Add, trunc, Op0, "", inst);
  } else if (d.isNegative() && magics.m.isStrictlyPositive()) {
    trunc = BinaryOperator::Create(Instruction::Sub, trunc, Op0, "", inst);
  }
  if (magics.s > 0) {
    APInt apS = APInt(32, magics.s);
    Constant *magicShift = ConstantInt::get(inst->getType(), apS);
    trunc = BinaryOperator::Create(Instruction::AShr, trunc,
      magicShift, "", inst);
  }

  APInt ap31 = APInt(32, 31);
  Constant *thirtyOne = ConstantInt::get(inst->getType(), ap31);
  // get sign bit
  Instruction *sign = BinaryOperator::Create(Instruction::LShr, trunc,
    thirtyOne, "", inst);
  
  Instruction *result = BinaryOperator::Create(Instruction::Add, trunc, sign,
    "");
  ReplaceInstWithInst(inst->getParent()->getInstList(), ii, result);
  return true;
}

int ARMTTIImpl::getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
                              Type *Ty) {
  // Division by a constant can be turned into multiplication, but only if we
  // know it's constant. So it's not so much that the immediate is cheap (it's
  // not), but that the alternative is worse.
  // FIXME: this is probably unneeded with GlobalISel.
  if ((Opcode == Instruction::SDiv || Opcode == Instruction::UDiv ||
       Opcode == Instruction::SRem || Opcode == Instruction::URem) &&
      Idx == 1)
    return 0;

  if (Opcode == Instruction::And) {
    // UXTB/UXTH
    if (Imm == 255 || Imm == 65535)
      return 0;
    // Conversion to BIC is free, and means we can use ~Imm instead.
    return std::min(getIntImmCost(Imm, Ty), getIntImmCost(~Imm, Ty));
  }

  if (Opcode == Instruction::Add)
    // Conversion to SUB is free, and means we can use -Imm instead.
    return std::min(getIntImmCost(Imm, Ty), getIntImmCost(-Imm, Ty));

  if (Opcode == Instruction::ICmp && Imm.isNegative() &&
      Ty->getIntegerBitWidth() == 32) {
    int64_t NegImm = -Imm.getSExtValue();
    if (ST->isThumb2() && NegImm < 1<<12)
      // icmp X, #-C -> cmn X, #C
      return 0;
    if (ST->isThumb() && NegImm < 1<<8)
      // icmp X, #-C -> adds X, #C
      return 0;
  }

  // xor a, -1 can always be folded to MVN
  if (Opcode == Instruction::Xor && Imm.isAllOnesValue())
    return 0;

  return getIntImmCost(Imm, Ty);
}

static std::string toString(const APFloat &FP) {
  // Print NaNs with custom payloads specially.
  if (FP.isNaN() &&
      !FP.bitwiseIsEqual(APFloat::getQNaN(FP.getSemantics())) &&
      !FP.bitwiseIsEqual(APFloat::getQNaN(FP.getSemantics(), /*Negative=*/true))) {
    APInt AI = FP.bitcastToAPInt();
    return
        std::string(AI.isNegative() ? "-" : "") + "nan:0x" +
        utohexstr(AI.getZExtValue() &
                  (AI.getBitWidth() == 32 ? INT64_C(0x007fffff) :
                                            INT64_C(0x000fffffffffffff)),
                  /*LowerCase=*/true);
  }

  // Use C99's hexadecimal floating-point representation.
  static const size_t BufBytes = 128;
  char buf[BufBytes];
  auto Written = FP.convertToHexString(
      buf, /*hexDigits=*/0, /*upperCase=*/false, APFloat::rmNearestTiesToEven);
  (void)Written;
  assert(Written != 0);
  assert(Written < BufBytes);
  return buf;
}

//.........这里部分代码省略.........

    APInt CastResV = constantFoldCast(V->getValue(), Builtin);

    // Add the literal instruction to represent the result of the cast.
    SILBuilderWithScope B(BI);
    return B.createIntegerLiteral(BI->getLoc(), BI->getType(), CastResV);
  }

  // Process special builtins that are designed to check for overflows in
  // integer conversions.
  case BuiltinValueKind::SToSCheckedTrunc:
  case BuiltinValueKind::UToUCheckedTrunc:
  case BuiltinValueKind::SToUCheckedTrunc:
  case BuiltinValueKind::UToSCheckedTrunc:
  case BuiltinValueKind::SUCheckedConversion:
  case BuiltinValueKind::USCheckedConversion: {
    return constantFoldAndCheckIntegerConversions(BI, Builtin, ResultsInError);
  }

  case BuiltinValueKind::IntToFPWithOverflow: {
    // Get the value. It should be a constant in most cases.
    // Note, this will not always be a constant, for example, when analyzing
    // _convertFromBuiltinIntegerLiteral function itself.
    auto *V = dyn_cast<IntegerLiteralInst>(Args[0]);
    if (!V)
      return nullptr;
    APInt SrcVal = V->getValue();
    Type DestTy = Builtin.Types[1];

    APFloat TruncVal(
        DestTy->castTo<BuiltinFloatType>()->getAPFloatSemantics());
    APFloat::opStatus ConversionStatus = TruncVal.convertFromAPInt(
        SrcVal, /*isSigned=*/true, APFloat::rmNearestTiesToEven);

    SILLocation Loc = BI->getLoc();
    const ApplyExpr *CE = Loc.getAsASTNode<ApplyExpr>();

    // Check for overflow.
    if (ConversionStatus & APFloat::opOverflow) {
      // If we overflow and are not asked for diagnostics, just return nullptr.
      if (!ResultsInError.hasValue())
        return nullptr;

      SmallString<10> SrcAsString;
      SrcVal.toString(SrcAsString, /*radix*/10, true /*isSigned*/);
      
      // Otherwise emit our diagnostics and then return nullptr.
      diagnose(M.getASTContext(), Loc.getSourceLoc(),
               diag::integer_literal_overflow,
               CE ? CE->getType() : DestTy, SrcAsString);
      ResultsInError = Optional<bool>(true);
      return nullptr;
    }

    // The call to the builtin should be replaced with the constant value.
    SILBuilderWithScope B(BI);
    return B.createFloatLiteral(Loc, BI->getType(), TruncVal);
  }

  case BuiltinValueKind::FPTrunc: {
    // Get the value. It should be a constant in most cases.
    auto *V = dyn_cast<FloatLiteralInst>(Args[0]);
    if (!V)
      return nullptr;
    APFloat TruncVal = V->getValue();
    Type DestTy = Builtin.Types[1];
    bool losesInfo;
    APFloat::opStatus ConversionStatus = TruncVal.convert(
        DestTy->castTo<BuiltinFloatType>()->getAPFloatSemantics(),
        APFloat::rmNearestTiesToEven, &losesInfo);
    SILLocation Loc = BI->getLoc();

    // Check if conversion was successful.
    if (ConversionStatus != APFloat::opStatus::opOK &&
        ConversionStatus != APFloat::opStatus::opInexact) {
      return nullptr;
    }

    // The call to the builtin should be replaced with the constant value.
    SILBuilderWithScope B(BI);
    return B.createFloatLiteral(Loc, BI->getType(), TruncVal);
  }

  case BuiltinValueKind::AssumeNonNegative: {
    auto *V = dyn_cast<IntegerLiteralInst>(Args[0]);
    if (!V)
      return nullptr;

    APInt VInt = V->getValue();
    if (VInt.isNegative() && ResultsInError.hasValue()) {
      diagnose(M.getASTContext(), BI->getLoc().getSourceLoc(),
               diag::wrong_non_negative_assumption,
               VInt.toString(/*Radix*/ 10, /*Signed*/ true));
      ResultsInError = Optional<bool>(true);
    }
    return V;
  }
  }
  return nullptr;
}

static SILInstruction *
constantFoldAndCheckIntegerConversions(BuiltinInst *BI,
                                       const BuiltinInfo &Builtin,
                                       Optional<bool> &ResultsInError) {
  assert(Builtin.ID == BuiltinValueKind::SToSCheckedTrunc ||
         Builtin.ID == BuiltinValueKind::UToUCheckedTrunc ||
         Builtin.ID == BuiltinValueKind::SToUCheckedTrunc ||
         Builtin.ID == BuiltinValueKind::UToSCheckedTrunc ||
         Builtin.ID == BuiltinValueKind::SUCheckedConversion ||
         Builtin.ID == BuiltinValueKind::USCheckedConversion);

  // Check if we are converting a constant integer.
  OperandValueArrayRef Args = BI->getArguments();
  auto *V = dyn_cast<IntegerLiteralInst>(Args[0]);
  if (!V)
    return nullptr;
  APInt SrcVal = V->getValue();

  // Get source type and bit width.
  Type SrcTy = Builtin.Types[0];
  uint32_t SrcBitWidth =
    Builtin.Types[0]->castTo<BuiltinIntegerType>()->getGreatestWidth();

  // Compute the destination (for SrcBitWidth < DestBitWidth) and enough info
  // to check for overflow.
  APInt Result;
  bool OverflowError;
  Type DstTy;

  // Process conversions signed <-> unsigned for same size integers.
  if (Builtin.ID == BuiltinValueKind::SUCheckedConversion ||
      Builtin.ID == BuiltinValueKind::USCheckedConversion) {
    DstTy = SrcTy;
    Result = SrcVal;
    // Report an error if the sign bit is set.
    OverflowError = SrcVal.isNegative();

  // Process truncation from unsigned to signed.
  } else if (Builtin.ID != BuiltinValueKind::UToSCheckedTrunc) {
    assert(Builtin.Types.size() == 2);
    DstTy = Builtin.Types[1];
    uint32_t DstBitWidth =
      DstTy->castTo<BuiltinIntegerType>()->getGreatestWidth();
    //     Result = trunc_IntFrom_IntTo(Val)
    //   For signed destination:
    //     sext_IntFrom(Result) == Val ? Result : overflow_error
    //   For signed destination:
    //     zext_IntFrom(Result) == Val ? Result : overflow_error
    Result = SrcVal.trunc(DstBitWidth);
    // Get the signedness of the destination.
    bool Signed = (Builtin.ID == BuiltinValueKind::SToSCheckedTrunc);
    APInt Ext = Signed ? Result.sext(SrcBitWidth) : Result.zext(SrcBitWidth);
    OverflowError = (SrcVal != Ext);

  // Process the rest of truncations.
  } else {
    assert(Builtin.Types.size() == 2);
    DstTy = Builtin.Types[1];
    uint32_t DstBitWidth =
      Builtin.Types[1]->castTo<BuiltinIntegerType>()->getGreatestWidth();
    // Compute the destination (for SrcBitWidth < DestBitWidth):
    //   Result = trunc_IntTo(Val)
    //   Trunc  = trunc_'IntTo-1bit'(Val)
    //   zext_IntFrom(Trunc) == Val ? Result : overflow_error
    Result = SrcVal.trunc(DstBitWidth);
    APInt TruncVal = SrcVal.trunc(DstBitWidth - 1);
    OverflowError = (SrcVal != TruncVal.zext(SrcBitWidth));
  }

  // Check for overflow.
  if (OverflowError) {
    // If we are not asked to emit overflow diagnostics, just return nullptr on
    // overflow.
    if (!ResultsInError.hasValue())
      return nullptr;

    SILLocation Loc = BI->getLoc();
    SILModule &M = BI->getModule();
    const ApplyExpr *CE = Loc.getAsASTNode<ApplyExpr>();
    Type UserSrcTy;
    Type UserDstTy;
    // Primitive heuristics to get the user-written type.
    // Eventually we might be able to use SILLocation (when it contains info
    // about inlined call chains).
    if (CE) {
      if (const TupleType *RTy = CE->getArg()->getType()->getAs<TupleType>()) {
        if (RTy->getNumElements() == 1) {
          UserSrcTy = RTy->getElementType(0);
          UserDstTy = CE->getType();
        }
      } else {
        UserSrcTy = CE->getArg()->getType();
        UserDstTy = CE->getType();
      }
    }
    
 
    // Assume that we are converting from a literal if the Source size is
    // 2048. Is there a better way to identify conversions from literals?
    bool Literal = (SrcBitWidth == 2048);
//.........这里部分代码省略.........