C++ ConstantInt::getName方法代码示例

//.........这里部分代码省略.........
    Match = match(In, m_And(m_Shl(m_Value(BF), m_ConstantInt(CSL)),
                      m_ConstantInt(CM)));
    if (Match && NoSR0)
      return false;
  }
  if (!Match) {
    // (and (lshr x, #sr), #m)
    LogicalSR = true;
    CSL = ConstantInt::get(Type::getInt32Ty(Ctx), 0);
    Match = match(In, m_And(m_LShr(m_Value(BF), m_ConstantInt(CSR)),
                            m_ConstantInt(CM)));
  }
  if (!Match) {
    // (and (ashr x, #sr), #m)
    LogicalSR = false;
    CSL = ConstantInt::get(Type::getInt32Ty(Ctx), 0);
    Match = match(In, m_And(m_AShr(m_Value(BF), m_ConstantInt(CSR)),
                            m_ConstantInt(CM)));
  }
  if (!Match) {
    CM = nullptr;
    // (shl (lshr x, #sr), #sl)
    LogicalSR = true;
    Match = match(In, m_Shl(m_LShr(m_Value(BF), m_ConstantInt(CSR)),
                            m_ConstantInt(CSL)));
  }
  if (!Match) {
    CM = nullptr;
    // (shl (ashr x, #sr), #sl)
    LogicalSR = false;
    Match = match(In, m_Shl(m_AShr(m_Value(BF), m_ConstantInt(CSR)),
                            m_ConstantInt(CSL)));
  }
  if (!Match)
    return false;

  Type *Ty = BF->getType();
  if (!Ty->isIntegerTy())
    return false;
  unsigned BW = Ty->getPrimitiveSizeInBits();
  if (BW != 32 && BW != 64)
    return false;

  uint32_t SR = CSR->getZExtValue();
  uint32_t SL = CSL->getZExtValue();

  if (!CM) {
    // If there was no and, and the shift left did not remove all potential
    // sign bits created by the shift right, then extractu cannot reproduce
    // this value.
    if (!LogicalSR && (SR > SL))
      return false;
    APInt A = APInt(BW, ~0ULL).lshr(SR).shl(SL);
    CM = ConstantInt::get(Ctx, A);
  }

  // CM is the shifted-left mask. Shift it back right to remove the zero
  // bits on least-significant positions.
  APInt M = CM->getValue().lshr(SL);
  uint32_t T = M.countTrailingOnes();

  // During the shifts some of the bits will be lost. Calculate how many
  // of the original value will remain after shift right and then left.
  uint32_t U = BW - std::max(SL, SR);
  // The width of the extracted field is the minimum of the original bits
  // that remain after the shifts and the number of contiguous 1s in the mask.
  uint32_t W = std::min(U, T);
  if (W == 0)
    return false;

  // Check if the extracted bits are contained within the mask that it is
  // and-ed with. The extract operation will copy these bits, and so the
  // mask cannot any holes in it that would clear any of the bits of the
  // extracted field.
  if (!LogicalSR) {
    // If the shift right was arithmetic, it could have included some 1 bits.
    // It is still ok to generate extract, but only if the mask eliminates
    // those bits (i.e. M does not have any bits set beyond U).
    APInt C = APInt::getHighBitsSet(BW, BW-U);
    if (M.intersects(C) || !M.isMask(W))
      return false;
  } else {
    // Check if M starts with a contiguous sequence of W times 1 bits. Get
    // the low U bits of M (which eliminates the 0 bits shifted in on the
    // left), and check if the result is APInt's "mask":
    if (!M.getLoBits(U).isMask(W))
      return false;
  }

  IRBuilder<> IRB(In);
  Intrinsic::ID IntId = (BW == 32) ? Intrinsic::hexagon_S2_extractu
                                   : Intrinsic::hexagon_S2_extractup;
  Module *Mod = BB->getParent()->getParent();
  Value *ExtF = Intrinsic::getDeclaration(Mod, IntId);
  Value *NewIn = IRB.CreateCall(ExtF, {BF, IRB.getInt32(W), IRB.getInt32(SR)});
  if (SL != 0)
    NewIn = IRB.CreateShl(NewIn, SL, CSL->getName());
  In->replaceAllUsesWith(NewIn);
  return true;
}