From 3b61cd6ad738b8479bf216dcf736bb935e8812df Mon Sep 17 00:00:00 2001 From: Thiago Macieira Date: Sun, 20 Aug 2017 14:22:44 -0700 Subject: QStringView: De-inline the length calculation so we can use SSE2 Performance is more important in this case than the theoretical benefit of constexpr. This commit implements the SSE2 search for 16-bit null and it might be possible to implement the equivalent for AArch64 (investigation required). It also adds a fallback to wcslen() for systems where wchar_t is short (non-x86 Windows or 32-bit x86 build with -no-sse2). We can re-add the constexpr loop once the C++ language has a way of overloading constexpr and non-constexpr. GCC has a non-standard way to do that with __builtin_constant_p, which is also implemented in this commit, but note that the inline function is still not constexpr. Change-Id: I6e9274c1e7444ad48c81fffd14dcaacafda5ebdc Reviewed-by: Oswald Buddenhagen Reviewed-by: Thiago Macieira --- src/corelib/tools/qstringalgorithms.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'src/corelib/tools/qstringalgorithms.h') diff --git a/src/corelib/tools/qstringalgorithms.h b/src/corelib/tools/qstringalgorithms.h index e1b8b90428..eaa7207bec 100644 --- a/src/corelib/tools/qstringalgorithms.h +++ b/src/corelib/tools/qstringalgorithms.h @@ -53,6 +53,8 @@ class QLatin1String; class QStringView; template class QVector; +Q_REQUIRED_RESULT Q_CORE_EXPORT Q_DECL_PURE_FUNCTION qssize_t qustrlen(const ushort *str) Q_DECL_NOTHROW; + Q_REQUIRED_RESULT Q_CORE_EXPORT Q_DECL_PURE_FUNCTION int qCompareStrings(QStringView lhs, QStringView rhs, Qt::CaseSensitivity cs = Qt::CaseSensitive) Q_DECL_NOTHROW; Q_REQUIRED_RESULT Q_CORE_EXPORT Q_DECL_PURE_FUNCTION int qCompareStrings(QStringView lhs, QLatin1String rhs, Qt::CaseSensitivity cs = Qt::CaseSensitive) Q_DECL_NOTHROW; Q_REQUIRED_RESULT Q_CORE_EXPORT Q_DECL_PURE_FUNCTION int qCompareStrings(QLatin1String lhs, QStringView rhs, Qt::CaseSensitivity cs = Qt::CaseSensitive) Q_DECL_NOTHROW; -- cgit v1.2.3