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Compile with Clang.

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This bug surfaced after we switched Mac over to use
clang's libstdc++, which has __builtin_popcount but
does not mark it as constexpr.

Change-Id: I4260af48b00c6db3322e52fb113075d305b1e1ec
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>
This commit is contained in:
Morten Johan Sørvig 2013-04-18 07:19:03 +02:00 committed by The Qt Project
parent 94758589fe
commit c5a3cfa488
1 changed files with 17 additions and 4 deletions
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21
src/corelib/tools/qalgorithms.h
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@ -516,9 +516,17 @@ Q_OUTOFLINE_TEMPLATE RandomAccessIterator qBinaryFindHelper(RandomAccessIterator
} //namespace QAlgorithmsPrivate
// Use __builtin_popcount on gcc. Clang claims to be gcc
// but has a bug where __builtin_popcount is not marked as
// constexpr.
#if defined(Q_CC_GNU) && !defined(Q_CC_CLANG)
#define QALGORITHMS_USE_BUILTIN_POPCOUNT
#endif
Q_DECL_CONSTEXPR inline uint qPopulationCount(quint32 v)
{
#ifdef Q_CC_GNU
#ifdef QALGORITHMS_USE_BUILTIN_POPCOUNT
return __builtin_popcount(v);
#else
// See http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel
@ -531,7 +539,7 @@ Q_DECL_CONSTEXPR inline uint qPopulationCount(quint32 v)
Q_DECL_CONSTEXPR inline uint qPopulationCount(quint8 v)
{
#ifdef Q_CC_GNU
#ifdef QALGORITHMS_USE_BUILTIN_POPCOUNT
return __builtin_popcount(v);
#else
return
@ -541,7 +549,7 @@ Q_DECL_CONSTEXPR inline uint qPopulationCount(quint8 v)
Q_DECL_CONSTEXPR inline uint qPopulationCount(quint16 v)
{
#ifdef Q_CC_GNU
#ifdef QALGORITHMS_USE_BUILTIN_POPCOUNT
return __builtin_popcount(v);
#else
return
@ -552,7 +560,7 @@ Q_DECL_CONSTEXPR inline uint qPopulationCount(quint16 v)
Q_DECL_CONSTEXPR inline uint qPopulationCount(quint64 v)
{
#ifdef Q_CC_GNU
#ifdef QALGORITHMS_USE_BUILTIN_POPCOUNT
return __builtin_popcountll(v);
#else
return
@ -570,6 +578,11 @@ Q_DECL_CONSTEXPR inline uint qPopulationCount(long unsigned int v)
return qPopulationCount(static_cast<quint64>(v));
}
#if defined(Q_CC_GNU) && !defined(Q_CC_CLANG)
#undef QALGORITHMS_USE_BUILTIN_POPCOUNT
#endif
QT_END_NAMESPACE
#endif // QALGORITHMS_H