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Introduce always constexpr variants of qNextPowerOfTwo

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Amends e464e1eb8eb63c631fb0916c3ea4540a88d8aad3. qNextPowerOfTwo has the
same issue as qCountTrailingZeroBits.

Change-Id: Ib1905986e932ac130bce7a1d98f4f7b5ef73991f
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
This commit is contained in:
Fabian Kosmale 2020-03-17 09:02:03 +01:00
parent f66a5c2d61
commit 7ef3826497
1 changed files with 35 additions and 18 deletions
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53
src/corelib/kernel/qmath.h
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@ -243,14 +243,8 @@ Q_DECL_CONSTEXPR inline double qRadiansToDegrees(double radians)
return radians * (180 / M_PI); return radians * (180 / M_PI);
} }
namespace QtPrivate {
Q_DECL_RELAXED_CONSTEXPR inline quint32 qNextPowerOfTwo(quint32 v) constexpr inline quint32 qConstexprNextPowerOfTwo(quint32 v) {
{
#if defined(QT_HAS_BUILTIN_CLZ)
if (v == 0)
return 1;
return 2U << (31 ^ QAlgorithmsPrivate::qt_builtin_clz(v));
#else
v |= v >> 1; v |= v >> 1;
v |= v >> 2; v |= v >> 2;
v |= v >> 4; v |= v >> 4;
@ -258,16 +252,9 @@ Q_DECL_RELAXED_CONSTEXPR inline quint32 qNextPowerOfTwo(quint32 v)
v |= v >> 16; v |= v >> 16;
++v; ++v;
return v; return v;
#endif
} }
Q_DECL_RELAXED_CONSTEXPR inline quint64 qNextPowerOfTwo(quint64 v) constexpr inline quint64 qConstexprNextPowerOfTwo(quint64 v) {
{
#if defined(QT_HAS_BUILTIN_CLZLL)
if (v == 0)
return 1;
return Q_UINT64_C(2) << (63 ^ QAlgorithmsPrivate::qt_builtin_clzll(v));
#else
v |= v >> 1; v |= v >> 1;
v |= v >> 2; v |= v >> 2;
v |= v >> 4; v |= v >> 4;
@ -276,15 +263,45 @@ Q_DECL_RELAXED_CONSTEXPR inline quint64 qNextPowerOfTwo(quint64 v)
v |= v >> 32; v |= v >> 32;
++v; ++v;
return v; return v;
}
constexpr inline quint32 qConstexprNextPowerOfTwo(qint32 v) {
return qConstexprNextPowerOfTwo(quint32(v));
}
constexpr inline quint32 qConstexprNextPowerOfTwo(qint64 v) {
return qConstexprNextPowerOfTwo(quint64(v));
}
}
constexpr inline quint32 qNextPowerOfTwo(quint32 v)
{
#if defined(QT_HAS_BUILTIN_CLZ)
if (v == 0)
return 1;
return 2U << (31 ^ QAlgorithmsPrivate::qt_builtin_clz(v));
#else
return QtPrivate::qConstexprNextPowerOfTwo(v);
#endif #endif
} }
Q_DECL_RELAXED_CONSTEXPR inline quint32 qNextPowerOfTwo(qint32 v) constexpr inline quint64 qNextPowerOfTwo(quint64 v)
{
#if defined(QT_HAS_BUILTIN_CLZLL)
if (v == 0)
return 1;
return Q_UINT64_C(2) << (63 ^ QAlgorithmsPrivate::qt_builtin_clzll(v));
#else
return QtPrivate::qConstexprNextPowerOfTwo(v);
#endif
}
constexpr inline quint32 qNextPowerOfTwo(qint32 v)
{ {
return qNextPowerOfTwo(quint32(v)); return qNextPowerOfTwo(quint32(v));
} }
Q_DECL_RELAXED_CONSTEXPR inline quint64 qNextPowerOfTwo(qint64 v) constexpr inline quint64 qNextPowerOfTwo(qint64 v)
{ {
return qNextPowerOfTwo(quint64(v)); return qNextPowerOfTwo(quint64(v));
} }