Method udiv

ext/src/llvm/APInt.cpp:1599–1635

}

APInt APInt::udiv(const APInt &RHS) const {
  assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");

  // First, deal with the easy case
  if (isSingleWord()) {
    assert(RHS.U.VAL != 0 && "Divide by zero?");
    return APInt(BitWidth, U.VAL / RHS.U.VAL);
  }

  // Get some facts about the LHS and RHS number of bits and words
  unsigned lhsWords = getNumWords(getActiveBits());
  unsigned rhsBits  = RHS.getActiveBits();
  unsigned rhsWords = getNumWords(rhsBits);
  assert(rhsWords && "Divided by zero???");

  // Deal with some degenerate cases
  if (!lhsWords)
    // 0 / X ===> 0
    return APInt(BitWidth, 0);
  if (rhsBits == 1)
    // X / 1 ===> X
    return *this;
  if (lhsWords < rhsWords || this->ult(RHS))
    // X / Y ===> 0, iff X < Y
    return APInt(BitWidth, 0);
  if (*this == RHS)
    // X / X ===> 1
    return APInt(BitWidth, 1);
  if (lhsWords == 1) // rhsWords is 1 if lhsWords is 1.
    // All high words are zero, just use native divide
    return APInt(BitWidth, this->U.pVal[0] / RHS.U.pVal[0]);

  // We have to compute it the hard way. Invoke the Knuth divide algorithm.
  APInt Quotient(BitWidth, 0); // to hold result.
  divide(U.pVal, lhsWords, RHS.U.pVal, rhsWords, Quotient.U.pVal, nullptr);
  return Quotient;
}

APInt APInt::udiv(uint64_t RHS) const {
  assert(RHS != 0 && "Divide by zero?");