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| author | Marc Mutz <marc.mutz@kdab.com> | 2012-05-20 13:10:27 +0200 |
|---|---|---|
| committer | The Qt Project <gerrit-noreply@qt-project.org> | 2013-04-03 11:38:35 +0200 |
| commit | 52ebf1f1914cea563b52baffc607407dbc6a7313 (patch) | |
| tree | b968c5e5b0196a55b201015db8401b56fe8a00a1 /src/corelib/tools/qalgorithms.h | |
| parent | 76e0223619da02911d02813961ef631a5e02d826 (diff) | |
With GCC, use __builtin_popcount{,l,ll} for qPopulationCount()
Change-Id: Ied7a98fa17404f1d9678bfbc1ced4817ab52f40e
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>
Diffstat (limited to 'src/corelib/tools/qalgorithms.h')
| -rw-r--r-- | src/corelib/tools/qalgorithms.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/src/corelib/tools/qalgorithms.h b/src/corelib/tools/qalgorithms.h index 2658cfc2c2..fecb9120eb 100644 --- a/src/corelib/tools/qalgorithms.h +++ b/src/corelib/tools/qalgorithms.h @@ -518,28 +518,43 @@ Q_OUTOFLINE_TEMPLATE RandomAccessIterator qBinaryFindHelper(RandomAccessIterator Q_DECL_CONSTEXPR inline uint qPopulationCount(quint32 v) { +#ifdef Q_CC_GNU + return __builtin_popcount(v); +#else // See http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel return (((v ) & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f + (((v >> 12) & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f + (((v >> 24) & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f; +#endif } Q_DECL_CONSTEXPR inline uint qPopulationCount(quint8 v) { +#ifdef Q_CC_GNU + return __builtin_popcount(v); +#else return (((v ) & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f; +#endif } Q_DECL_CONSTEXPR inline uint qPopulationCount(quint16 v) { +#ifdef Q_CC_GNU + return __builtin_popcount(v); +#else return (((v ) & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f + (((v >> 12) & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f; +#endif } Q_DECL_CONSTEXPR inline uint qPopulationCount(quint64 v) { +#ifdef Q_CC_GNU + return __builtin_popcountll(v); +#else return (((v ) & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f + (((v >> 12) & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f + @@ -547,6 +562,7 @@ Q_DECL_CONSTEXPR inline uint qPopulationCount(quint64 v) (((v >> 36) & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f + (((v >> 48) & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f + (((v >> 60) & 0xfff) * Q_UINT64_C(0x1001001001001) & Q_UINT64_C(0x84210842108421)) % 0x1f; +#endif } Q_DECL_CONSTEXPR inline uint qPopulationCount(long unsigned int v) |