QStringList: use a functor instead of a function pointer for std::sort

A function pointer requires aggressive optimization to inline. A function object
otoh is inlined by compilers two decades old.

Even shaves off 544B in text size off of a -O3 GCC 4.7 QtCore build.

Change-Id: Ibfd41654257360fa0f118701f502e6c23a6c28b3
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>

1 files changed, 9 insertions, 4 deletions

diff --git a/src/corelib/tools/qstringlist.cpp b/src/corelib/tools/qstringlist.cpp
index a47af4adbd..30be41a4bd 100644
--- a/src/corelib/tools/qstringlist.cpp
+++ b/src/corelib/tools/qstringlist.cpp
@@ -221,9 +221,14 @@ QT_BEGIN_NAMESPACE
     integer index.
 */
 
-static inline bool caseInsensitiveLessThan(const QString &s1, const QString &s2)
-{
-   return s1.compare(s2, Qt::CaseInsensitive) < 0;
+namespace {
+struct CaseInsensitiveLessThan {
+    typedef bool result_type;
+    result_type operator()(const QString &s1, const QString &s2) const
+    {
+        return s1.compare(s2, Qt::CaseInsensitive) < 0;
+    }
+};
 }
 
 void QtPrivate::QStringList_sort(QStringList *that, Qt::CaseSensitivity cs)
@@ -231,7 +236,7 @@ void QtPrivate::QStringList_sort(QStringList *that, Qt::CaseSensitivity cs)
     if (cs == Qt::CaseSensitive)
         std::sort(that->begin(), that->end());
     else
-        std::sort(that->begin(), that->end(), caseInsensitiveLessThan);
+        std::sort(that->begin(), that->end(), CaseInsensitiveLessThan());
 }