From e41b45f1aedf1b3fe0ca4b22226ccc23bc71ab7c Mon Sep 17 00:00:00 2001 From: Marc Mutz Date: Fri, 8 Aug 2014 10:31:36 +0200 Subject: QPair: add constexpr liberally MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On templates, adding constexpr makes a given instantiation constexpr if it can be. This turns qMakePair(0,0), say, into a compile-time constant. The effects on existing code are small, but exist: $ size lib/*{-baseline,-paircexp} | sort -nr 6516727 211192 2608 6730527 66b31f lib/libQt5Widgets.so.5.4.0-baseline 6516711 211192 2608 6730511 66b30f lib/libQt5Widgets.so.5.4.0-paircexp 5373720 44492 15976 5434188 52eb4c lib/libQt5Core.so.5.4.0-baseline 5373504 44492 15976 5433972 52ea74 lib/libQt5Core.so.5.4.0-paircexp 5107206 125072 6080 5238358 4fee56 lib/libQt5Gui.so.5.4.0-baseline 5107030 125072 6080 5238182 4feda6 lib/libQt5Gui.so.5.4.0-paircexp 1341290 30180 2600 1374070 14f776 lib/libQt5Network.so.5.4.0-baseline 1341210 30180 2600 1373990 14f726 lib/libQt5Network.so.5.4.0-paircexp # no other libraries benefit [ChangeLog][QtCore][QPair] Can now be used in C++11 constexpr contexts. Change-Id: I3872e6aa33a7d02a168516f4dfa7119efcac8c40 Reviewed-by: Olivier Goffart Reviewed-by: Jędrzej Nowacki --- src/corelib/tools/qpair.h | 22 +++++++++++----------- tests/auto/corelib/tools/qpair/tst_qpair.cpp | 17 ++++++++++++++++- 2 files changed, 27 insertions(+), 12 deletions(-) diff --git a/src/corelib/tools/qpair.h b/src/corelib/tools/qpair.h index 9b8691a3d8..cfc8035a48 100644 --- a/src/corelib/tools/qpair.h +++ b/src/corelib/tools/qpair.h @@ -53,18 +53,18 @@ struct QPair typedef T1 first_type; typedef T2 second_type; - QPair() : first(), second() {} - QPair(const T1 &t1, const T2 &t2) : first(t1), second(t2) {} + Q_DECL_CONSTEXPR QPair() : first(), second() {} + Q_DECL_CONSTEXPR QPair(const T1 &t1, const T2 &t2) : first(t1), second(t2) {} // compiler-generated copy/move ctor/assignment operators are fine! template - QPair(const QPair &p) : first(p.first), second(p.second) {} + Q_DECL_CONSTEXPR QPair(const QPair &p) : first(p.first), second(p.second) {} template QPair &operator=(const QPair &p) { first = p.first; second = p.second; return *this; } #ifdef Q_COMPILER_RVALUE_REFS template - QPair(QPair &&p) : first(std::move(p.first)), second(std::move(p.second)) {} + Q_DECL_CONSTEXPR QPair(QPair &&p) : first(std::move(p.first)), second(std::move(p.second)) {} template QPair &operator=(QPair &&p) { first = std::move(p.first); second = std::move(p.second); return *this; } @@ -80,39 +80,39 @@ template class QTypeInfo > : public QTypeInfoMerger, T1, T2> {}; // Q_DECLARE_TYPEINFO template -Q_INLINE_TEMPLATE bool operator==(const QPair &p1, const QPair &p2) +Q_DECL_CONSTEXPR Q_INLINE_TEMPLATE bool operator==(const QPair &p1, const QPair &p2) { return p1.first == p2.first && p1.second == p2.second; } template -Q_INLINE_TEMPLATE bool operator!=(const QPair &p1, const QPair &p2) +Q_DECL_CONSTEXPR Q_INLINE_TEMPLATE bool operator!=(const QPair &p1, const QPair &p2) { return !(p1 == p2); } template -Q_INLINE_TEMPLATE bool operator<(const QPair &p1, const QPair &p2) +Q_DECL_CONSTEXPR Q_INLINE_TEMPLATE bool operator<(const QPair &p1, const QPair &p2) { return p1.first < p2.first || (!(p2.first < p1.first) && p1.second < p2.second); } template -Q_INLINE_TEMPLATE bool operator>(const QPair &p1, const QPair &p2) +Q_DECL_CONSTEXPR Q_INLINE_TEMPLATE bool operator>(const QPair &p1, const QPair &p2) { return p2 < p1; } template -Q_INLINE_TEMPLATE bool operator<=(const QPair &p1, const QPair &p2) +Q_DECL_CONSTEXPR Q_INLINE_TEMPLATE bool operator<=(const QPair &p1, const QPair &p2) { return !(p2 < p1); } template -Q_INLINE_TEMPLATE bool operator>=(const QPair &p1, const QPair &p2) +Q_DECL_CONSTEXPR Q_INLINE_TEMPLATE bool operator>=(const QPair &p1, const QPair &p2) { return !(p1 < p2); } template -Q_OUTOFLINE_TEMPLATE QPair qMakePair(const T1 &x, const T2 &y) +Q_DECL_CONSTEXPR Q_OUTOFLINE_TEMPLATE QPair qMakePair(const T1 &x, const T2 &y) { return QPair(x, y); } diff --git a/tests/auto/corelib/tools/qpair/tst_qpair.cpp b/tests/auto/corelib/tools/qpair/tst_qpair.cpp index 05031dbbf8..59b0ffb95e 100644 --- a/tests/auto/corelib/tools/qpair/tst_qpair.cpp +++ b/tests/auto/corelib/tools/qpair/tst_qpair.cpp @@ -42,12 +42,13 @@ #include #include +#include class tst_QPair : public QObject { Q_OBJECT private Q_SLOTS: - void dummy() {} + void testConstexpr(); }; class C { char _[4]; }; @@ -101,5 +102,19 @@ Q_STATIC_ASSERT(!QTypeInfo::isDummy ); Q_STATIC_ASSERT(!QTypeInfo::isPointer); +void tst_QPair::testConstexpr() +{ + Q_CONSTEXPR QPair pID = qMakePair(0, 0.0); + Q_UNUSED(pID); + + Q_CONSTEXPR QPair pDD = qMakePair(0.0, 0.0); + Q_CONSTEXPR QPair pDD2 = qMakePair(0, 0.0); // involes (rvalue) conversion ctor + Q_CONSTEXPR bool equal = pDD2 == pDD; + QVERIFY(equal); + + Q_CONSTEXPR QPair pSI = qMakePair(QSize(4, 5), 6); + Q_UNUSED(pSI); +} + QTEST_APPLESS_MAIN(tst_QPair) #include "tst_qpair.moc" -- cgit v1.2.3