* include/std/bit (__countl_zero, __countr_zero, __popcount): Use
local variables for number of digits instead of type aliases.
(__log2p1): Remove redundant branch also checked in __countl_zero.
Tested powerpc64le-linux, committed to trunk.
commit b5cb477ecf9e98d10f4608bd2d94f57ee3bd48e5
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Tue Jul 24 14:10:01 2018 +0100
Minor refactoring in <bit> header
* include/std/bit (__countl_zero, __countr_zero, __popcount): Use
local variables for number of digits instead of type aliases.
(__log2p1): Remove redundant branch also checked in __countl_zero.
diff --git a/libstdc++-v3/include/std/bit b/libstdc++-v3/include/std/bit
index a23f2ba60d1..0aebac28758 100644
--- a/libstdc++-v3/include/std/bit
+++ b/libstdc++-v3/include/std/bit
@@ -62,45 +62,44 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
constexpr int
__countl_zero(_Tp __x) noexcept
{
- using __limits = numeric_limits<_Tp>;
+ constexpr auto _Nd = numeric_limits<_Tp>::digits;
if (__x == 0)
- return __limits::digits;
+ return _Nd;
- using __limits_ull = numeric_limits<unsigned long long>;
- using __limits_ul = numeric_limits<unsigned long>;
- using __limits_u = numeric_limits<unsigned>;
+ constexpr auto _Nd_ull = numeric_limits<unsigned long long>::digits;
+ constexpr auto _Nd_ul = numeric_limits<unsigned long>::digits;
+ constexpr auto _Nd_u = numeric_limits<unsigned>::digits;
- if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_u::digits)
+ if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_u)
{
- constexpr int __diff = __limits_u::digits - __limits::digits;
+ constexpr int __diff = _Nd_u - _Nd;
return __builtin_clz(__x) - __diff;
}
- else if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_ul::digits)
+ else if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_ul)
{
- constexpr int __diff = __limits_ul::digits - __limits::digits;
+ constexpr int __diff = _Nd_ul - _Nd;
return __builtin_clzl(__x) - __diff;
}
- else if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_ull::digits)
+ else if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_ull)
{
- constexpr int __diff = __limits_ull::digits - __limits::digits;
+ constexpr int __diff = _Nd_ull - _Nd;
return __builtin_clzll(__x) - __diff;
}
- else // (__limits::digits > __limits_ull::digits)
+ else // (_Nd > _Nd_ull)
{
- static_assert(__limits::digits <= (2 * __limits_ull::digits),
+ static_assert(_Nd <= (2 * _Nd_ull),
"Maximum supported integer size is 128-bit");
- unsigned long long __high = __x >> __limits_ull::digits;
+ unsigned long long __high = __x >> _Nd_ull;
if (__high != 0)
{
- constexpr int __diff
- = (2 * __limits_ull::digits) - __limits::digits;
+ constexpr int __diff = (2 * _Nd_ull) - _Nd;
return __builtin_clzll(__high) - __diff;
}
- unsigned long long __low = __x & __limits_ull::max();
- return (__limits::digits - __limits_ull::digits)
- + __builtin_clzll(__low);
+ constexpr auto __max_ull = numeric_limits<unsigned long long>::max();
+ unsigned long long __low = __x & __max_ull;
+ return (_Nd - _Nd_ull) + __builtin_clzll(__low);
}
}
@@ -117,31 +116,32 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
constexpr int
__countr_zero(_Tp __x) noexcept
{
- using __limits = numeric_limits<_Tp>;
+ constexpr auto _Nd = numeric_limits<_Tp>::digits;
if (__x == 0)
- return __limits::digits;
+ return _Nd;
- using __limits_ull = numeric_limits<unsigned long long>;
- using __limits_ul = numeric_limits<unsigned long>;
- using __limits_u = numeric_limits<unsigned>;
+ constexpr auto _Nd_ull = numeric_limits<unsigned long long>::digits;
+ constexpr auto _Nd_ul = numeric_limits<unsigned long>::digits;
+ constexpr auto _Nd_u = numeric_limits<unsigned>::digits;
- if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_u::digits)
+ if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_u)
return __builtin_ctz(__x);
- else if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_ul::digits)
+ else if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_ul)
return __builtin_ctzl(__x);
- else if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_ull::digits)
+ else if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_ull)
return __builtin_ctzll(__x);
- else // (__limits::digits > __limits_ull::digits)
+ else // (_Nd > _Nd_ull)
{
- static_assert(__limits::digits <= (2 * __limits_ull::digits),
+ static_assert(_Nd <= (2 * _Nd_ull),
"Maximum supported integer size is 128-bit");
- unsigned long long __low = __x & __limits_ull::max();
+ constexpr auto __max_ull = numeric_limits<unsigned long long>::max();
+ unsigned long long __low = __x & __max_ull;
if (__low != 0)
return __builtin_ctzll(__low);
- unsigned long long __high = __x >> __limits_ull::digits;
- return __builtin_ctzll(__high) + __limits_ull::digits;
+ unsigned long long __high = __x >> _Nd_ull;
+ return __builtin_ctzll(__high) + _Nd_ull;
}
}
@@ -158,28 +158,29 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
constexpr int
__popcount(_Tp __x) noexcept
{
- using __limits = numeric_limits<_Tp>;
+ constexpr auto _Nd = numeric_limits<_Tp>::digits;
if (__x == 0)
return 0;
- using __limits_ull = numeric_limits<unsigned long long>;
- using __limits_ul = numeric_limits<unsigned long>;
- using __limits_u = numeric_limits<unsigned>;
+ constexpr auto _Nd_ull = numeric_limits<unsigned long long>::digits;
+ constexpr auto _Nd_ul = numeric_limits<unsigned long>::digits;
+ constexpr auto _Nd_u = numeric_limits<unsigned>::digits;
- if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_u::digits)
+ if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_u)
return __builtin_popcount(__x);
- else if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_ul::digits)
+ else if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_ul)
return __builtin_popcountl(__x);
- else if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_ull::digits)
+ else if _GLIBCXX17_CONSTEXPR (_Nd <= _Nd_ull)
return __builtin_popcountll(__x);
- else // (__limits::digits > __limits_ull::digits)
+ else // (_Nd > _Nd_ull)
{
- static_assert(__limits::digits <= (2 * __limits_ull::digits),
+ static_assert(_Nd <= (2 * _Nd_ull),
"Maximum supported integer size is 128-bit");
- unsigned long long __low = __x & __limits_ull::max();
- unsigned long long __high = __x >> __limits_ull::digits;
+ constexpr auto __max_ull = numeric_limits<unsigned long long>::max();
+ unsigned long long __low = __x & __max_ull;
+ unsigned long long __high = __x >> _Nd_ull;
return __builtin_popcountll(__low) + __builtin_popcountll(__high);
}
}
@@ -214,8 +215,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__log2p1(_Tp __x) noexcept
{
constexpr auto _Nd = numeric_limits<_Tp>::digits;
- if (__x == 0)
- return 0;
return _Nd - std::__countl_zero(__x);
}
