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Simplify conversions around arithmetic operators #270

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merged 4 commits into from
May 24, 2022
Merged

Simplify conversions around arithmetic operators #270

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24cce06
Simplify conversions for operator+
chfast May 5, 2022
efe920e
Simplify conversions for operator-
chfast May 16, 2022
bc88cb8
Simplify conversions for operator*
chfast May 16, 2022
1c3c141
Simplify conversions for operator/ and operator%
chfast May 16, 2022
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212 changes: 53 additions & 159 deletions include/intx/intx.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1068,6 +1068,58 @@ struct uint
static_assert(sizeof(Int) <= sizeof(uint64_t));
return static_cast<Int>(words_[0]);
}

friend inline constexpr uint operator+(const uint& x, const uint& y) noexcept
{
return addc(x, y).value;
}

inline constexpr uint& operator+=(const uint& y) noexcept { return *this = *this + y; }

inline constexpr uint operator-() const noexcept { return ~*this + uint{1}; }

friend inline constexpr uint operator-(const uint& x, const uint& y) noexcept
{
return subc(x, y).value;
}

inline constexpr uint& operator-=(const uint& y) noexcept { return *this = *this - y; }

/// Multiplication implementation using word access
/// and discarding the high part of the result product.
friend inline constexpr uint operator*(const uint& x, const uint& y) noexcept
{
uint<N> p;
for (size_t j = 0; j < num_words; j++)
{
uint64_t k = 0;
for (size_t i = 0; i < (num_words - j - 1); i++)
{
const auto a = addc(p[i + j], k);
const auto t = umul(x[i], y[j]) + uint128{a.value, a.carry};
p[i + j] = t[0];
k = t[1];
}
p[num_words - 1] += x[num_words - j - 1] * y[j] + k;
}
return p;
}

inline constexpr uint& operator*=(const uint& y) noexcept { return *this = *this * y; }

friend inline constexpr uint operator/(const uint& x, const uint& y) noexcept
{
return udivrem(x, y).quot;
}

friend inline constexpr uint operator%(const uint& x, const uint& y) noexcept
{
return udivrem(x, y).rem;
}

inline constexpr uint& operator/=(const uint& y) noexcept { return *this = *this / y; }

inline constexpr uint& operator%=(const uint& y) noexcept { return *this = *this % y; }
};

using uint192 = uint<192>;
Expand Down Expand Up @@ -1458,38 +1510,6 @@ inline const uint8_t* as_bytes(const T& x) noexcept
return reinterpret_cast<const uint8_t*>(&x);
}

template <unsigned N>
inline constexpr uint<N> operator+(const uint<N>& x, const uint<N>& y) noexcept
{
return addc(x, y).value;
}

template <unsigned N>
inline constexpr uint<N> operator-(const uint<N>& x) noexcept
{
return ~x + uint<N>{1};
}

template <unsigned N>
inline constexpr uint<N> operator-(const uint<N>& x, const uint<N>& y) noexcept
{
return subc(x, y).value;
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N>& operator+=(uint<N>& x, const T& y) noexcept
{
return x = x + y;
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N>& operator-=(uint<N>& x, const T& y) noexcept
{
return x = x - y;
}

template <unsigned N>
inline constexpr uint<2 * N> umul(const uint<N>& x, const uint<N>& y) noexcept
{
Expand All @@ -1511,36 +1531,6 @@ inline constexpr uint<2 * N> umul(const uint<N>& x, const uint<N>& y) noexcept
return p;
}

/// Multiplication implementation using word access
/// and discarding the high part of the result product.
template <unsigned N>
inline constexpr uint<N> operator*(const uint<N>& x, const uint<N>& y) noexcept
{
constexpr auto num_words = uint<N>::num_words;

uint<N> p;
for (size_t j = 0; j < num_words; j++)
{
uint64_t k = 0;
for (size_t i = 0; i < (num_words - j - 1); i++)
{
const auto a = addc(p[i + j], k);
const auto t = umul(x[i], y[j]) + uint128{a.value, a.carry};
p[i + j] = t[0];
k = t[1];
}
p[num_words - 1] += x[num_words - j - 1] * y[j] + k;
}
return p;
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N>& operator*=(uint<N>& x, const T& y) noexcept
{
return x = x * y;
}

template <unsigned N>
inline constexpr uint<N> exp(uint<N> base, uint<N> exponent) noexcept
{
Expand Down Expand Up @@ -1785,7 +1775,7 @@ inline void udivrem_knuth(
} // namespace internal

template <unsigned M, unsigned N>
div_result<uint<M>, uint<N>> udivrem(const uint<M>& u, const uint<N>& v) noexcept
constexpr div_result<uint<M>, uint<N>> udivrem(const uint<M>& u, const uint<N>& v) noexcept
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Was this constexpr just missed?

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Owner Author

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Yes. Maybe we never used it in constexpr context but now compiler is not happy as we removed one level of templates and maybe it is obviously wrong now.

{
auto na = internal::normalize(u, v);

Expand Down Expand Up @@ -1839,32 +1829,6 @@ inline constexpr div_result<uint<N>> sdivrem(const uint<N>& u, const uint<N>& v)
return {q_is_neg ? -res.quot : res.quot, u_is_neg ? -res.rem : res.rem};
}

template <unsigned N>
inline constexpr uint<N> operator/(const uint<N>& x, const uint<N>& y) noexcept
{
return udivrem(x, y).quot;
}

template <unsigned N>
inline constexpr uint<N> operator%(const uint<N>& x, const uint<N>& y) noexcept
{
return udivrem(x, y).rem;
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N>& operator/=(uint<N>& x, const T& y) noexcept
{
return x = x / y;
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N>& operator%=(uint<N>& x, const T& y) noexcept
{
return x = x % y;
}

template <unsigned N>
inline constexpr uint<N> bswap(const uint<N>& x) noexcept
{
Expand All @@ -1878,76 +1842,6 @@ inline constexpr uint<N> bswap(const uint<N>& x) noexcept

// Support for type conversions for binary operators.

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N> operator+(const uint<N>& x, const T& y) noexcept
{
return x + uint<N>(y);
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N> operator+(const T& x, const uint<N>& y) noexcept
{
return uint<N>(x) + y;
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N> operator-(const uint<N>& x, const T& y) noexcept
{
return x - uint<N>(y);
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N> operator-(const T& x, const uint<N>& y) noexcept
{
return uint<N>(x) - y;
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N> operator*(const uint<N>& x, const T& y) noexcept
{
return x * uint<N>(y);
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N> operator*(const T& x, const uint<N>& y) noexcept
{
return uint<N>(x) * y;
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N> operator/(const uint<N>& x, const T& y) noexcept
{
return x / uint<N>(y);
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N> operator/(const T& x, const uint<N>& y) noexcept
{
return uint<N>(x) / y;
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N> operator%(const uint<N>& x, const T& y) noexcept
{
return x % uint<N>(y);
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N> operator%(const T& x, const uint<N>& y) noexcept
{
return uint<N>(x) % y;
}

template <unsigned N, typename T,
typename = typename std::enable_if<std::is_convertible<T, uint<N>>::value>::type>
inline constexpr uint<N> operator|(const uint<N>& x, const T& y) noexcept
Expand Down